WorldWideScience

Sample records for celestial navigation

  1. Celestial navigation in a nutshell

    CERN Document Server

    Schlereth, Hewitt

    2000-01-01

    Celestial Navigation in a Nutshell demonstrates how to take sights by the sun, moon, stars, and planets, discussing the advantages and disadvantages of each method. The reader is taken carefully through several examples and situational illustrations, making this a most effective self-teaching guide. Common errors are reviewed and several tips on how to improve accuracy are given.

  2. Celestial Navigation in the USA, Fiji, and Tunisia

    Science.gov (United States)

    Holbrook, Jarita C.

    2015-05-01

    Today there are many coastal communities that are home to navigators who use stars for position finding at night; I was, however, unaware of this fact when I began researching celestial navigation practices in 1997. My project focused on three communities: the Moce Islanders of Fiji, the Kerkennah Islanders in Tunisia, and the U.S. Navy officers and students at the United States Naval Academy, Annapolis, Maryland. My goal was to answer the question of why people continue to navigate by the stars, but also to understand the role of technology in their navigation practices. Using anthropology techniques of ethnography including participant observation, formal and informal interviews, audio and videotaping, I gathered data over five years at the three communities. I began by learning the details of how they use the stars for navigation. Next, I learned about who did the navigation and where they learned to navigate. I gathered opinions on various navigation aids and instruments, and opinions about the future of using the stars for navigation. I listened to the stories that they told about navigating. In the United States I worked in English, in Fiji, in Fijian and English, and in Tunisia, French and English. For the formal interviews I worked with translators. The navigators use stars for navigating today but the future of their techniques is not certain. Though practiced today, these celestial navigation traditions have undergone and continue to undergo changes. New navigational technologies are part of the stimulation for change, thus 'a meeting of different worlds' is symbolized by peoples encounters with these technologies.

  3. Spacecraft autonomous navigation using unscented particle filter-based celestial/Doppler information fusion

    International Nuclear Information System (INIS)

    With the development of space missions, especially manned space missions, a reliable and secure navigation system, and assured autonomous capability in case of emergencies in space, is needed. In order to compensate for the insufficiency of ground station tracking and control, a new autonomous celestial/Doppler-integrated navigation method for a spacecraft is proposed. Celestial navigation is a fully autonomous navigation method, but in some situations the navigation accuracy of this method is subject to the inaccuracies of the measuring devices. Doppler navigation can serve as a good complement to celestial navigation. Because both the state and the measurement models of a celestial/Doppler- integrated navigation system are nonlinear and non-Gaussian, the unscented particle filter (UPF) based information fusion method is proposed here to fuse the position signals from the celestial navigation and Doppler navigation subsystems, and to enhance the navigation accuracy. The performance of this new method is tested and examined using actual spacecraft-orbit data. Simulations show that the position and velocity accuracies are estimated to within 300 m and 0.5 m s−1 respectively, which demonstrate the feasibility and effectiveness of this method. Moreover, it can be used as a backup system to provide redundancy

  4. Principles of Celestial Navigation: An Online Resource for Introducing Practical Astronomy to the Public

    Science.gov (United States)

    Urban, Sean E.

    2015-08-01

    Astronomy is often called a "gateway" science because it inspires appreciation and awe among children and non-scientists. Applied astronomy, with practical, real-world applications, can entice even the most utilitarian people to take notice and learn about the subject. Traditional celestial navigation is an astronomy topic that captures the attention of the public. The U.S. Naval Observatory has led the development of a publicly available online celestial navigation educational module titled, "Principles of Celestial Navigation". It can be used world-wide to introduce people to astronomy. This poster describes some of the aspects of this teaching module.

  5. Advanced Spacecraft Navigation and Timing Using Celestial Gamma-Ray Sources Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed novel program will use measurements of the high-energy photon output from gamma-ray celestial sources to design a new, unique navigation system. This...

  6. IN-FLIGHT ALIGNMENT OF INERTIAL NAVIGATION SYSTEM BY CELESTIAL OBSERVATION TECHNIQUE

    Institute of Scientific and Technical Information of China (English)

    ALlJamshaid; FANGJian-cheng

    2005-01-01

    This paper presents an in-flight alignment technique for a strapdown inertial navigation system (SINS) and employs a star pattern recognition procedure for identifying stars sensed by a CCD electrooptical star sensor.Collinearity equations are used to estimate sensor frame star coordinates and the conventional least square differential correction method is used to estimate the unknown orientation angles. A comparison of this attitude with the attitude estimated by the SINS provides axis misalignment angles. Simulations using a Kalman filter are carried out for an SINS and the system employs a local level navigation frame. The space stabilized SINS is discussed in conjunction with the celestial aiding. Based on the observation of the Kalman filter, the estimating and compensating gyro errors, as well as the position and velocity errors caused by the SINS misalignments are calibrated by celestial attitute information.

  7. Reclaiming Celestial Navigation Using a Contemporary Hawaiian Worldview of the Heavens

    Science.gov (United States)

    Dye, Ahia G.; Ha`o, Celeste; Slater, Timothy F.; Slater, Stephanie J.

    2015-08-01

    The immense challenges of successfully navigating the vast Pacific basin without modern instruments are well-known. At the same time, the precise methods used by ancient Polynesian wayfinders are largely undocumented, the strategies being wholly unfamiliar to early European navigators from higher latitudes with formal training in charts and tables. Leading the wave of a Hawaiian-Renaissance, contemporary Hawaiian seafarers are boldly reclaiming their heritage by recreating and sailing double hulled canoes by instrument-free, navigation techniques. Many of these navigational techniques are probably reminiscent of earlier strategies, and are proving to be highly successful. The result is that numerous canoes are now making repeated trips throughout the Polynesian Triangle, and reaching beyond to soon circumnavigate the globe. Not surprisingly, a vital component of any navigational system far from terrestrial landmarks is based on the changing positions and predictable motions of the Sun and stars. Although many of the indigenous star names are lost to history, some of the most important star names for celestial navigation have been painstakingly re-claimed. Other critically important navigational stars are being named by the respected Hawaiian Guild Navigators and their teams of educators who are conducting navigation training for Hawaiian sailing crews. The authors are collecting and documenting these new star names along-with their identifiable asterisms-in the service of educating both the public and the next generation of navigators.

  8. Using Time Zones and Celestial Navigation to Teach the Phases of the Moon

    Science.gov (United States)

    O'Donoghue, A.

    2011-09-01

    The phases of the moon are typically presented to introductory astronomy classes in a diagram showing the position of the moon, its appearance and elongation at each phase, and the time of each phase's transit. Though wonderfully compact and efficient at conveying information, I have found it to be overwhelming to non-science major students. Much of their difficulty arises from their vague definition of time, which must be broadened for them to understand the different rising, transit, and setting times for the phases of the moon. Working with time zones helps them recognize that the time on their watch is relative to a particular longitude and the transit of the sun at that longitude. Celestial Navigation extends this to the transit of all celestial objects and helps them re-define "time of day" to a position on Earth relative to the Earth-Sun line in a practical way. Once they understand why a given object transits at the same time for all time zones, extending this to the moon is much simpler. My students are quickly able to identify the transit times of the various phases of the moon, and with some additional instruction, quickly learn how to figure out their rising and setting times as well. On this poster, I will include images from PowerPoint animations and the student exercises I use to help them understand the concepts. Though I have too small a sample for statistical analysis (24 students/semester), I have found that student scores on moon phase questions on exams have improved since I incorporated time zones and celestial navigation into my course.

  9. Dual-EKF-Based Real-Time Celestial Navigation for Lunar Rover

    Directory of Open Access Journals (Sweden)

    Li Xie

    2012-01-01

    Full Text Available A key requirement of lunar rover autonomous navigation is to acquire state information accurately in real-time during its motion and set up a gradual parameter-based nonlinear kinematics model for the rover. In this paper, we propose a dual-extended-Kalman-filter- (dual-EKF- based real-time celestial navigation (RCN method. The proposed method considers the rover position and velocity on the lunar surface as the system parameters and establishes a constant velocity (CV model. In addition, the attitude quaternion is considered as the system state, and the quaternion differential equation is established as the state equation, which incorporates the output of angular rate gyroscope. Therefore, the measurement equation can be established with sun direction vector from the sun sensor and speed observation from the speedometer. The gyro continuous output ensures the algorithm real-time operation. Finally, we use the dual-EKF method to solve the system equations. Simulation results show that the proposed method can acquire the rover position and heading information in real time and greatly improve the navigation accuracy. Our method overcomes the disadvantage of the cumulative error in inertial navigation.

  10. Autonomous navigation method of high elliptical orbit satellite based on celestial navigation and GPS%基于天文/GPS的HEO卫星自主导航方法

    Institute of Scientific and Technical Information of China (English)

    王鹏; 张迎春

    2015-01-01

    为了实现大椭圆轨道(HEO)卫星高精度自主导航,提出一种将直接敏感地平天文导航与全球定位系统(GPS)相结合的组合导航方法.首先,分析卫星轨道��2运动模型及其所受空间摄动,建立卫星轨道动力学模型;然后,分析单一使用天文导航和GPS的优缺点,根据HEO卫星对GPS的可见性,提出在远地点只采用天文导航,而在近地点采用以天文导航为主、适时引入GPS信号进行位速测量辅助修正的方法.通过计算机仿真和结果分析表明了所提出的设计方法导航精度比单一天文导航提高72.4%∼85.6%.%In order to realize autonomous and continuous navigation information outputs for high elliptical orbit(HEO) satellite, new integrated navigation system is proposed based on celestial navigation of directly sensing stellar and global positioning system(GPS) navigation. Firstly, satellite orbit motion model is established on the satellite orbit dynamics��2 model and suffered space perturbation. Moreover, performances of single-use celestial navigation or GPS are analyzed. When the satellite is near the apogee, observation system is established by using only celestial navigation. When the satellite is near the perigee, the estimate covariance is revised through incoming GPS signal to improve the celestial navigation estimate. The autonomous navigation system is designed and simulating. The results of computer simulation show that the navigation accuracy is improved by 72.4%∼85.6%compared with the celestial navigation method.

  11. Automatic Solar and Celestial Navigation on the Moon and Mars Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Micro-Space proposes to develop a low mass, automated form of the classic navigator's bubble sextant, with no moving parts, for rapid localization and reliable...

  12. Celestial X-ray Source Modeling and Catalogues for Spacecraft Navigation and Timing Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Microcosm X-ray pulsar-based navigation and timing (XNAV) team will provide the software and modeling infrastructure for NASA to support XNAV operations,...

  13. 基于信息融合的自主天文导航方法%Method of autonomous celestial navigation based on information fusion

    Institute of Scientific and Technical Information of China (English)

    王鹏; 张迎春

    2012-01-01

    Direct sensing horizon and indirect sensing horizon are two typical kinds of autonomous celestial navigation method. Direct sensing horizon is simply and reliable, but the navigation precision that depends mainly on earth sensor is lower. Indirect sensing horizon gets horizon information by observing atmosphere refraction stellar using the star sensor. Because the numbers of refraction stellar and observing time are limited, the observed information is discontinuous. A new method of autonomous celestial navigation using both of the two methods based on information fusion is presented. The new information is imported when refraction stars cannot be observed. Simulation results show that the proposed method can improve the precision and reliability of the navigation system.%直接敏感地平和间接敏感地平是典型的两种自主天文导航方法,直接敏感地平简单可靠,但是由于地球敏感器精度较低,因此导航精度不高;利用星光折射的间接敏感地平精度较高,但是折射星数量有限并且观测时段较短.针对上述两种方法的缺点,提出一种基于信息融合的自主天文导航方法.当观测不到折射星时引入新信息,弥补间接敏感地平自主导航的不足.通过对多种导航模式进行数值仿真与分析,验证所设计方法提高了系统的导航精度和可靠性.

  14. 火星探测器自主天文导航方法研究%Research on autonomous celestials navigation method of Mars probe

    Institute of Scientific and Technical Information of China (English)

    金鸿

    2015-01-01

    This thesis suggests an autonomous celestial navigation method which is based on celestial observation,which uses the angle informa-tion of Mars and its satellites( starlight angular distance),combined with the movement model of Mars probe. Then we can figure out the precise position( real time)of Mars probe with Unscented Kalman filter. The result from computer simulation proved to be effective.%提出了一种基于天文观测的火星探测器自主天文导航方法,该方法利用由星敏感器视场内测量得到的火星及其卫星和某一恒星之间的星光角距,结合火星探测器的运动模型,通过Unscented卡尔曼滤波方法,即可获得高精度的火星探测器实时位置信息,计算机仿真结果证明了该方法的有效性。

  15. 机载天文导航系统中振动对导航精度的影响%Influence of vibration in the airborne celestial navigation system on navigation accuracy

    Institute of Scientific and Technical Information of China (English)

    董强; 马彩文; 李艳; 杨晓许; 袁辉

    2015-01-01

    针对平台式机载天文自主导航系统载体振动对导航系统定位精度的影响问题,理论分析了载体对导航平台影响的振动形式,给出振动角位移是主要影响量的结论。研究了天文导航系统的单星定位导航建模思路,根据振动角位移的特点给出了角位移补偿中近似坐标转换矩阵。设计了振动实验,建立了定位模型,给出了载体振动主要以角位移的形式将误差传递给导航系统平台。试验结果表明:振动角位移带来的误差为天文导航定位的主要影响因素,X、Y轴200″的轴向振动角位移带给天文导航系统的定位误差近似为600 m。%For the issue of the influence of aircraft vibration on the navigation system positioning accuracy based on airborne autonomous celestial navigation system, an analysis of navigation platform vibration influenced from aircraft was preceded.Furthermore, a conclusion was given that the main factor is vibration angular displacement.Next, a single stellar positioning model in the celestial navigation system was established.According to the characteristics of vibration angular displacement, the similar coordinate transformation matrix in the angular displacement compensa-tion was given.The results of vibration experiment and positioning model simulation validated that the angular vibra-tion is the main error propagation to navigation system platform.The positioning error of celestial navigation system is 600 m when vibration angular displacement is 200 s along the x and y axis.

  16. Celestial Treasury

    Science.gov (United States)

    Lachièze-Rey, Marc; Luminet, Jean-Pierre

    2001-07-01

    Throughout history, the mysterious dark skies have inspired our imaginations in countless ways, influencing our endeavors in science and philosophy, religion, literature, and art. Filled with 380 full-color illustrations, Celestial Treasury shows the influence of astronomical theories and the richness of illustrations in Western civilization through the ages. The authors explore the evolution of our understanding of astronomy and weave together ancient and modern theories in a fascinating narrative. They incorporate a wealth of detail from Greek verse, medieval manuscripts and Victorian poetry with contemporary spacecraft photographs and computer-generated star charts. Celestial Treasury is more than a beautiful book: it answers a variety of questions that have intrigued scientists and laymen for centuries. -- How did philosophers and scientists try to explain the order that governs celestial motion? -- How did geometers and artists measure and map the skies? -- How many different answers have been proposed for the most fundamental of all questions: When and how did Earth come about? -- Who inhabits the heavens--gods, angels or extraterrestrials? No other book recounts humankind's fascination with the heavens as compellingly as Celestial Treasury. Marc Lachièze-Rey is a director of research at the Centre National pour la Récherche Scientifique and astrophysicist at the Centre d'Etudes de Saclay. He is the author of The Cosmic Background Radiation (Cambridge, 1999), and and The Quest for Unity, (Oxford, 1999 ), as well as many books in French. Jean-Pierre Luminet is a research director of the Centre National pour la Rechérche Scientifique, based at the Paris-Meudon observatory. He is the author of Black Holes, (Cambridge 1992), as well as science documentaries for television.

  17. Celestial Burial Masters

    Institute of Scientific and Technical Information of China (English)

    YUQIAN

    2004-01-01

    Celestial burial is worshipped in Tibet as the highest pursuit of life. Of three elements indispensable for celestial burial-celestial rock (also known as altar), cinereous vultures, and masters of celestial burial, celestial burial masters are the most mysteriously important.

  18. Methods of celestial mechanics

    CERN Document Server

    Brouwer, Dirk

    2013-01-01

    Methods of Celestial Mechanics provides a comprehensive background of celestial mechanics for practical applications. Celestial mechanics is the branch of astronomy that is devoted to the motions of celestial bodies. This book is composed of 17 chapters, and begins with the concept of elliptic motion and its expansion. The subsequent chapters are devoted to other aspects of celestial mechanics, including gravity, numerical integration of orbit, stellar aberration, lunar theory, and celestial coordinates. Considerable chapters explore the principles and application of various mathematical metho

  19. Navigation systems

    OpenAIRE

    Ocepek, Marjan

    2013-01-01

    In this thesis we present different navigation systems which may be used also in surveying. Map as a basis of navigation is described at the beginning. Next, we focus on navigation based on celestial bodies. We present basic terms such as navigation and orientation and describe some primitive methods, which had been used for orientation without compass. We present two important time keeping instruments that facilitated the process of position determination, the chronometer and chronograph, an...

  20. 天文角度辅助的高超声速飞行器多信息融合导航算法%Multi-information fusion navigation algorithm assisted by celestial angle observation for hypersonic cruise vehicle

    Institute of Scientific and Technical Information of China (English)

    王融; 熊智; 刘建业; 钟丽娜

    2013-01-01

    The traditional inertial/celestial integrated navigation system (INS/CNS) is inapplicable for hypersonic vehicle, because it can’t work under the body coordinate accordance and single-star visible condition. In this paper, a tightly-coupled INS/GPS/CNS integrated navigation scheme for hypersonic vehicle is investigated. The new INS/CNS integrated model is built based on transformational relation between starlight elevation/azimuth and INS errors. The new model can stabilize the measurement noise characteristic and work under single-star visible condition, thus can improve the continuity and accuracy of INS/CNS integration. The simulation of hypersonic vehicle navigation indicates that, the system assisted by celestial angle observation shows 60%-70% improvement in attitude accuracy than the unassisted system.%常规惯性/天文组合导航方法难以直接应用于高超声速飞行器机载环境下以载体系为基准进行星光测量的情况,且在可见星只有一颗时无法连续组合。为此,构建了高超声速飞行器惯性/卫星/天文紧组合导航系统方案,通过分析载体系下星光仰角、方位角与惯导误差之间的转换关系,建立了载体系下惯性/天文角度组合模型。理论分析表明,该系统在只有一颗导航星时仍能辅助惯导工作,且可使观测噪声特性保持稳定,从而提高了天文对惯导辅助的连续性和组合滤波估计精度。仿真结果表明,在高超声速飞行器导航系统采用天文角度辅助后,姿态误差较无天文辅助情况的降低60%~70%。

  1. Burnham's celestial handbook

    CERN Document Server

    Burnham, Robert

    1978-01-01

    Volume II of a comprehensive three-part guide to celestial objects outside our solar system ranges from Chamaeleon to Orion. Features coordinates, classifications, physical descriptions, hundreds of visual aids. 1977 edition.

  2. Mesopotamian Celestial Divination

    Science.gov (United States)

    Verderame, Lorenzo

    Celestial divination was an important aspect of scholarly activity in Mesopotamia. Several hundred cuneiform tablets attest to its practice and provide details of the different types of omens that were drawn from observations of the sky. This chapter outlines the sources of celestial divination in Mesopotamia and traces the development of the divinatory tradition from the late third millennium BC down to the end of the first millennium BC.

  3. Burnham's celestial handbook

    CERN Document Server

    Burnham, Robert

    1978-01-01

    Volume III of this three-part comprehensive guide to the thousands of celestial objects outside our solar system concludes with listings from Pavo through Vulpecula. Objects are grouped according to constellation, and their definitions feature names, coordinates, classifications, and physical descriptions. Additional notes offer fascinating historical information. Hundreds of visual aids. 1977 edition.

  4. Burnham's celestial handbook

    CERN Document Server

    Burnham, Robert

    1978-01-01

    Volume I of this comprehensive three-part guide to the thousands of celestial objects outside our solar system ranges from Andromeda through Cetus. Objects are grouped according to constellation, and their definitions feature names, coordinates, classifications, and physical descriptions. Additional notes offer fascinating historical information. Hundreds of visual aids. 1977 edition.

  5. 基于非开普勒轨道的高超声速临近空间飞行器自主天文导航研究%Study on the Autonomous Celestial Navigation of Near Space Vehicles With Hypersonic Speed Based on Non-Keplerian Orbits

    Institute of Scientific and Technical Information of China (English)

    李海林; 吴德伟

    2012-01-01

    针对航天器自主导航方法不适合高超声速临近空间飞行器的问题,研究了基于非开普勒轨道的高超声速临近空间飞行器自主天文导航方案.论述了基于非开普勒轨道的自主天文导航机理,通过对高超声速临近空间飞行器受力分析,建立了动力学方程;利用矢量倒数法则推导出空间运动方程;设计了基于非开普勒轨道的状态模型和基于星光折射间接敏感地平的观测模型,采用卡尔曼滤波进行了仿真验证.仿真结果表明,基于非开普勒轨道的高超声速临近空间飞行器自主天文导航可达到较高的位置和速度精度.%In allusion to the problem that the aircraft autonomous celestial navigation is not suitable for the near space vehicles with hypersonic speed, an approach of the autonomous celestial navigation of near space vehicles with hypersonic speed based on non-Keplerian orbits is studied. Mechanism of the autonomous celestial navigation based on non-Keplerian is analyzed, and the dynamic equations are developed by analyzing the strength of near space vehicles with hypersonic speed. The space motion equation is educed using the vector derivatives rules. States model based on non-Keplerian orbits and measurement model using the concept of stellar horizon atmospheric refraction are de- signed, and the Kalman filter simulation is adopted. Results show that the autonomous celestial navigation of near space vehicles with hypersonic speed based on non-Keplerian orbits can meet the requirement of high precision for position and velocity, which is important for further research on the near space vehicles with hypersonic speed.

  6. A Snapshot-Based Mechanism for Celestial Orientation.

    Science.gov (United States)

    El Jundi, Basil; Foster, James J; Khaldy, Lana; Byrne, Marcus J; Dacke, Marie; Baird, Emily

    2016-06-01

    In order to protect their food from competitors, ball-rolling dung beetles detach a piece of dung from a pile, shape it into a ball, and roll it away along a straight path [1]. They appear to rely exclusively on celestial compass cues to maintain their bearing [2-8], but the mechanism that enables them to use these cues for orientation remains unknown. Here, we describe the orientation strategy that allows dung beetles to use celestial cues in a dynamic fashion. We tested the underlying orientation mechanism by presenting beetles with a combination of simulated celestial cues (sun, polarized light, and spectral cues). We show that these animals do not rely on an innate prediction of the natural geographical relationship between celestial cues, as other navigating insects seem to [9, 10]. Instead, they appear to form an internal representation of the prevailing celestial scene, a "celestial snapshot," even if that scene represents a physical impossibility for the real sky. We also find that the beetles are able to maintain their bearing with respect to the presented cues only if the cues are visible when the snapshot is taken. This happens during the "dance," a behavior in which the beetle climbs on top of its ball and rotates about its vertical axis [11]. This strategy for reading celestial signals is a simple but efficient mechanism for straight-line orientation. PMID:27185557

  7. Adventures in Celestial Mechanics

    CERN Document Server

    Szebehely, Victor G

    1998-01-01

    A fascinating introduction to the basic principles of orbital mechanics. It has been three hundred years since Isaac Newton first formulated laws to explain the orbits of the Moon and the planets of our solar system. In so doing he laid the groundwork for modern science's understanding of the workings of the cosmos and helped pave the way to the age of space exploration. Adventures in Celestial Mechanics offers students an enjoyable way to become acquainted with the basic principles involved in the motions of natural and human-made bodies in space. Packed with examples in which these principle

  8. Frontiers in relativistic celestial mechanics

    CERN Document Server

    2014-01-01

    Relativistic celestial mechanics – investigating the motion celestial bodies under the influence of general relativity – is a major tool of modern experimental gravitational physics. With a wide range of prominent authors from the field, this two-volume series consists of reviews on a multitude of advanced topics in the area of relativistic celestial mechanics – starting from more classical topics such as the regime of asymptotically-flat spacetime, light propagation and celestial ephemerides, but also including its role in cosmology and alternative theories of gravity as well as modern experiments in this area.

  9. The geometry of celestial mechanics

    CERN Document Server

    Geiges, Hansjörg

    2016-01-01

    Celestial mechanics is the branch of mathematical astronomy devoted to studying the motions of celestial bodies subject to the Newtonian law of gravitation. This mathematical introductory textbook reveals that even the most basic question in celestial mechanics, the Kepler problem, leads to a cornucopia of geometric concepts: conformal and projective transformations, spherical and hyperbolic geometry, notions of curvature, and the topology of geodesic flows. For advanced undergraduate and beginning graduate students, this book explores the geometric concepts underlying celestial mechanics and is an ideal companion for introductory courses. The focus on the history of geometric ideas makes it perfect supplementary reading for students in elementary geometry and topology. Numerous exercises, historical notes and an extensive bibliography provide all the contextual information required to gain a solid grounding in celestial mechanics.

  10. Celestial data routing network

    Science.gov (United States)

    Bordetsky, Alex

    2000-11-01

    Imagine that information processing human-machine network is threatened in a particular part of the world. Suppose that an anticipated threat of physical attacks could lead to disruption of telecommunications network management infrastructure and access capabilities for small geographically distributed groups engaged in collaborative operations. Suppose that small group of astronauts are exploring the solar planet and need to quickly configure orbital information network to support their collaborative work and local communications. The critical need in both scenarios would be a set of low-cost means of small team celestial networking. To the geographically distributed mobile collaborating groups such means would allow to maintain collaborative multipoint work, set up orbital local area network, and provide orbital intranet communications. This would be accomplished by dynamically assembling the network enabling infrastructure of the small satellite based router, satellite based Codec, and set of satellite based intelligent management agents. Cooperating single function pico satellites, acting as agents and personal switching devices together would represent self-organizing intelligent orbital network of cooperating mobile management nodes. Cooperative behavior of the pico satellite based agents would be achieved by comprising a small orbital artificial neural network capable of learning and restructing the networking resources in response to the anticipated threat.

  11. An introduction to celestial mechanics

    CERN Document Server

    Moulton, Forest Ray

    1984-01-01

    An unrivaled text in the field of celestial mechanics, Moulton's theoretical work on the prediction and interpretation of celestial phenomena has not been superseded. By providing a general account of all parts of celestial mechanics without an over-full treatment of any single aspect, by stating all the problems in advance, and, where the transformations are long, giving an outline of the steps which must be made, and by noting all the places where assumptions have been introduced or unjustified methods employed, Moulton has insured that his work will be valuable to all who are interested in

  12. The Principle and Application of Maser Navigation

    OpenAIRE

    Dong, Jiang

    2008-01-01

    The traditional celestial navigation system (CNS) is used the moon, stars, and planets as celestial guides. Then the star tracker (i.e. track one star or planet or angle between it) and star sensor (i.e. sense many star simultaneous) be used to determine the attitude of the spacecraft. Pulsar navigation also be introduced to CNS. Maser is another interested celestial in radio astronomy which has strong flux density as spectral line. Now we analysis the principle of maser navigation which base...

  13. Celestial mechanics with geometric algebra

    Science.gov (United States)

    Hestenes, D.

    1983-01-01

    Geometric algebra is introduced as a general tool for Celestial Mechanics. A general method for handling finite rotations and rotational kinematics is presented. The constants of Kepler motion are derived and manipulated in a new way. A new spinor formulation of perturbation theory is developed.

  14. The Inner Meaning of Outer Space: Human Nature and the Celestial Realm

    OpenAIRE

    Hubbard, Timothy L.

    2008-01-01

    Kant argued that humans possess a priori knowledge of space; although his argument focused on a physics of bodies, it also has implications for a psychology of beings. Many human cultures organize stars in the night sky into constellations (i.e., impose structure); attribute properties, behaviors, and abilities to objects in the celestial realm (i.e., impose meaning); and use perceived regularity in the celestial realms in development of calendars, long-range navigation, agriculture, and astr...

  15. Modern Questions of Celestial Mechanics

    CERN Document Server

    Colombo, Giovanni

    2011-01-01

    C. Agostinelli: Sul problema delle aurore boreali e il moto di un corpuscolo elettrizzato in presenza di un dipolo magnetico.- G. Colombo: Introduction to the theory of earth's motion about its center of mass.- E.M. Gaposchkin: The motion of the pole and the earth's elasticity as studied from the gravity field of the earth by means of artificial earth satellites.- I.I. Shapiro: Radar astronomy, general relativity, and celestial mechanics.- V. Szebehely: Applications of the restricted problem of three bodies in space research.- G.A. Wilkins: The analysis of the observation of the satellites of

  16. Observation of Celestial Phenomena in Ancient China

    Science.gov (United States)

    Sun, Xiaochun

    Because of the need for calendar-making and portent astrology, the Chinese were diligent and meticulous observers of celestial phenomena. China has maintained the longest continuous historical records of celestial phenomena in the world. Extraordinary or abnormal celestial events were particularly noted because of their astrological significance. The historical records cover various types of celestial phenomena, which include solar and lunar eclipses, sunspots, "guest stars" (novae or supernovae as we understand today), comets and meteors, and all kinds of planetary phenomena. These records provide valuable historical data for astronomical studies today.

  17. COMMISSION 7: Celestial Mechanics and Dynamical Astronomy

    Czech Academy of Sciences Publication Activity Database

    Milani, A.; Burns, J.A.; Hadjidemetriou, J.; Kneževic, Z.; Beaugé, C.; Erdi, B.; Fukushima, T.; Heggie, D. C.; Lemaitre, A.; Maciejewski, A.; Morbidelli, A.; Šidlichovský, Miloš; Vokrouhlický, D.; Zhou, J.-L.

    Cambridge: Cambridge University Press, 2007 - (Engvold, O.), s. 7-16. (Proceedings of the IAU. IAU Transactions. 26A). ISBN 978-0-521-85604-1 Institutional research plan: CEZ:AV0Z10030501 Keywords : celestial mechanics * resonances * exoplanets Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics

  18. Commission 7: Celestial Mechanics and Dynamical Astronomy

    Czech Academy of Sciences Publication Activity Database

    Burns, J.A.; Kneževic, Z.; Milani, A.; Athanassoula, E.; Beaugé, C.; Bálint, E.; Lematre, A.; Maciejewski, A.; Malhotra, R.; Morbidelli, A.; Peale, S.J.; Šidlichovský, Miloš; Vokrouhlický, D.; Zhou, J.

    Cambridge: Cambridge University Press, 2010 - (Corbett, I.), s. 120-122. (Proceedings of the International Astronomical Union. IAU Transactions. 27B). ISBN 978-0-521-76831-3 Institutional research plan: CEZ:AV0Z10030501 Keywords : celestial mechanics * resonances * exoplanets Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics

  19. Celestial mechanics and astrodynamics theory and practice

    CERN Document Server

    Gurfil, Pini

    2016-01-01

    This volume is designed as an introductory text and reference book for graduate students, researchers and practitioners in the fields of astronomy, astrodynamics, satellite systems, space sciences and astrophysics. The purpose of the book is to emphasize the similarities between celestial mechanics and astrodynamics, and to present recent advances in these two fields so that the reader can understand the inter-relations and mutual influences. The juxtaposition of celestial mechanics and astrodynamics is a unique approach that is expected to be a refreshing attempt to discuss both the mechanics of space flight and the dynamics of celestial objects. “Celestial Mechanics and Astrodynamics: Theory and Practice” also presents the main challenges and future prospects for the two fields in an elaborate, comprehensive and rigorous manner. The book presents homogenous and fluent discussions of the key problems, rendering a portrayal of recent advances in the field together with some basic concepts and essential in...

  20. Celestial mechanics of planet shells

    Science.gov (United States)

    Barkin, Yu V.; Vilke, V. G.

    2004-06-01

    The motion of a planet consisting of an external shell (mantle) and a core (rigid body), which are connected by a visco-elastic layer and mutually gravitationally interact with each other and with an external celestial body (considered as a material point), is studied (Barkin, 1999, 2002a,b; Vilke, 2004). Relative motions of the core and mantle are studied on the assumption that the centres of mass of the planet and external body move on unperturbed Keplerian orbits around the general centre of mass of the system. The core and mantle of the planet have axial symmetry and have different principal moments of inertia. The differential action of the external body on the core and mantle cause the periodic relative displacements of their centres of mass and their relative turns. An approximate solution of the problem was obtained on the basis of the linearization, averaging and small-parameter methods. The obtained analytical results are applied to the study of the possible relative displacements of the core and mantle of the Earth under the gravitational action of the Moon. For the suggested two-body Earth model and in the simple case of a circular (model) lunar orbit the new phenomenon of periodic translatory-rotary oscillations of the core with a fortnightly period the mantle was observed. The more remarkable phenomenon is the cyclic rotation with the same period (13.7 days) of the core relative to the mantle with a ‘large’ amplitude of 152 m (at the core surface).The results obtained confirm the general concept described by Barkin (1999, 2002a,b) that induced relative shell oscillations can control and dictate the cyclic and secular processes of energization of the planets and satellites in definite rhythms and on different time scales.The results obtained mean that giant moments and forces produce energy which causes in particular deformations of the viscoelastic layer between planet shells. This process is realized with different intensities on different time

  1. The Inner Meaning of Outer Space: Human Nature and the Celestial Realm

    Directory of Open Access Journals (Sweden)

    Timothy L. Hubbard

    2008-06-01

    Full Text Available Kant argued that humans possess a priori knowledge of space; although his argument focused on a physics of bodies, it also has implications for a psychology of beings. Many human cultures organize stars in the night sky into constellations (i.e., impose structure; attribute properties, behaviors, and abilities to objects in the celestial realm (i.e., impose meaning; and use perceived regularity in the celestial realms in development of calendars, long-range navigation, agriculture, and astrology (i.e., seek predictability and control. The physical inaccessibility of the celestial realm allows a potent source of metaphor, and also allows projection of myths regarding origin and ascension, places of power, and dwelling places of gods, immortals, and other souls. Developments in astronomy and cosmology infl uenced views of human nature and the place of humanity in the universe, and these changes parallel declines in egocentrism with human development. Views regarding alleged beings (e.g., angels, extraterrestrials from the celestial realm (and to how communicate with such beings are anthropocentric and ignore evolutionary factors in physical and cognitive development. It is suggested that in considering views and uses of the celestial realm, we learn not just about the universe, but also about ourselves. *

  2. Relativistic Celestial Mechanics of the Solar System

    Science.gov (United States)

    Kopeikin, Sergei; Efroimsky, Michael; Kaplan, George

    2011-09-01

    The general theory of relativity was developed by Einstein a century ago. Since then, it has become the standard theory of gravity, especially important to the fields of fundamental astronomy, astrophysics, cosmology, and experimental gravitational physics. Today, the application of general relativity is also essential for many practical purposes involving astrometry, navigation, geodesy, and time synchronization. Numerous experiments have successfully tested general relativity to a remarkable level of precision. Exploring relativistic gravity in the solar system now involves a variety of high-accuracy techniques, for example, very long baseline radio interferometry, pulsar timing, spacecraft Doppler tracking, planetary radio ranging, lunar laser ranging, the global positioning system (GPS), torsion balances and atomic clocks. Over the last few decades, various groups within the International Astronomical Union have been active in exploring the application of the general theory of relativity to the modeling and interpretation of high-accuracy astronomical observations in the solar system and beyond. A Working Group on Relativity in Celestial Mechanics and Astrometry was formed in 1994 to define and implement a relativistic theory of reference frames and time scales. This task was successfully completed with the adoption of a series of resolutions on astronomical reference systems, time scales, and Earth rotation models by the 24th General Assembly of the IAU, held in Manchester, UK, in 2000. However, these resolutions only form a framework for the practical application of relativity theory, and there have been continuing questions on the details of the proper application of relativity theory to many common astronomical problems. To ensure that these questions are properly addressed, the 26th General Assembly of the IAU, held in Prague in August 2006, established the IAU Commission 52, "Relativity in Fundamental Astronomy". The general scientific goals of the new

  3. Relativistic Celestial Mechanics of the Solar System

    CERN Document Server

    Kopeikin, Sergei; Kaplan, George

    2011-01-01

    This authoritative book presents the theoretical development of gravitational physics as it applies to the dynamics of celestial bodies and the analysis of precise astronomical observations. In so doing, it fills the need for a textbook that teaches modern dynamical astronomy with a strong emphasis on the relativistic aspects of the subject produced by the curved geometry of four-dimensional spacetime. The first three chapters review the fundamental principles of celestial mechanics and of special and general relativity. This background material forms the basis for understanding relativistic r

  4. The Celestial Vault: The Magic of Astrology

    Science.gov (United States)

    McGaha, J.

    2004-11-01

    Astrology is a "Geocentric System" that supports the "Astrological Principle". This principle, that human beings and their actions are influenced by the positions of celestial objects, is not objectively supported. The "planetary gods" found in the heavens provided order to help explain the chaotic events in life on earth. Is this why many people think their horoscopes are correct, with the "stars" taking credit? Do "celestial movements" foretell the future? What is the evidence for Astrology? The historical, psychological and physical foundations of astrology will be discussed.

  5. Dynamics of Natural and Artificial Celestial Bodies

    Science.gov (United States)

    Pretka-Ziomek, Halina; Wnuk, Edwin; Seidelmann, P. Kenneth; Richardson, David.

    2002-01-01

    This volume contains papers presented at the US/European Celestial Mechanics Workshop organized by the Astronomical Observatory of Adam Mickiewicz University in Poznan, Poland and held in Poznan, from 3 to 7 July 2000. The purpose of the workshop was to identify future research in celestial mechanics and astrometry and encourage collaboration among scientists from eastern and western countries. Also an emphasis was placed on attracting young members of the fields from around the world and encouraging them to undertake new research efforts needed for advancements in those fields. There was a full program of invited and contributed presentations on selected subjects and each day ended with a discussion period on a general subject in celestial mechanics. The discussion topics and the leaders were: Resonances and Chaos -- A. Morbidelli; Artificial Satellite Orbits -- K.T. Alfriend; Near Earth Objects -- K. Muinonen; Small Solar System Bodies -- I. Williams; and Summary -- P.K. Seidelmann. The goal of the discussions was to identify what we did not know and how we might further our knowledge. It was felt, in addition, that Poznan, Poland, with a core of scientists covering a range of ages, would provide an example of how a research and educational group could be developed elsewhere. Also, Poznan is a central location convenient to eastern and western countries. Thus, the gathering of people and the papers presented are to be the bases for building the future of astrometry and celestial mechanics. Link: http://www.wkap.nl/prod/b/1-4020-0115-0

  6. Orientation and navigation in birds

    OpenAIRE

    Bouwman, H.

    1998-01-01

    How birds orientate and navigate over long distances, remains one of the subjects of ornithology eliciting much interest. Birds use combinations of different sources of information to find direction and position. Some of these are the geomagnetic field, celestial bodies, mosaic and gradient maps, sound, smell, idiotetic information and others. Different species use different combinations of sources. This ability is partially inherent and partially learned.

  7. Orientation and navigation in birds

    Directory of Open Access Journals (Sweden)

    H. Bouwman

    1998-07-01

    Full Text Available How birds orientate and navigate over long distances, remains one of the subjects of ornithology eliciting much interest. Birds use combinations of different sources of information to find direction and position. Some of these are the geomagnetic field, celestial bodies, mosaic and gradient maps, sound, smell, idiotetic information and others. Different species use different combinations of sources. This ability is partially inherent and partially learned.

  8. Recent advances in celestial and space mechanics

    CERN Document Server

    Chyba, Monique

    2016-01-01

    This book presents recent advances in space and celestial mechanics, with a focus on the N-body problem and astrodynamics, and explores the development and application of computational techniques in both areas. It highlights the design of space transfers with various modes of propulsion, like solar sailing and low-thrust transfers between libration point orbits, as well as a broad range of targets and applications, like rendezvous with near Earth objects. Additionally, it includes contributions on the non-integrability properties of the collinear three- and four-body problem, and on general conditions for the existence of stable, minimum energy configurations in the full N-body problem. A valuable resource for physicists and mathematicians with research interests in celestial mechanics, astrodynamics and optimal control as applied to space transfers, as well as for professionals and companies in the industry.

  9. Celestial Ephemerides in an Expanding Universe

    CERN Document Server

    Kopeikin, Sergei

    2012-01-01

    Post-Newtonian theory was instrumental in conducting the critical experimental tests of general relativity and in building the astronomical ephemerides of celestial bodies in the solar system with an unparalleled precision. The cornerstone of the theory is the postulate that the solar system is gravitationally isolated from the rest of the universe and the background spacetime is asymptotically flat. The present article extends this theoretical concept and formulates the principles of celestial dynamics of particles and light moving in gravitational field of a localized astronomical system embedded to the expanding Friedmann-Lemaitre-Robertson-Walker (FLRW) universe. We formulate the precise mathematical concept of the Newtonian limit of Einstein's field equations in the conformally-flat FLRW spacetime and analyze the geodesic motion of massive particles and light in this limit. We prove that by doing conformal spacetime transformations, one can reduce the equations of motion of particles and light to the cla...

  10. GAOUA realizations of the Celestial Reference Frame

    Science.gov (United States)

    Yatskiv, Ya.; Bolotin, S.; Kur'yanova, A.

    2005-09-01

    Short overview of the activity of the Main Astronomical observatory of National Academy of Science of Ukraine for maintenance and extension of the International Celestial Reference Frame (ICRF) is presented. Special attention is paid on the time stabilities of positions of radio sources (RS) and on the selection of a subset of RS to be used for maintenance of the ICRF. It is shown that seven RS qualified by the IERS as defining sources are unstable.

  11. Use of Reference Frames for Interplanetary Navigation at JPL

    Science.gov (United States)

    Heflin, Michael; Jacobs, Chris; Sovers, Ojars; Moore, Angelyn; Owen, Sue

    2010-01-01

    Navigation of interplanetary spacecraft is typically based on range, Doppler, and differential interferometric measurements made by ground-based telescopes. Acquisition and interpretation of these observations requires accurate knowledge of the terrestrial reference frame and its orientation with respect to the celestial frame. Work is underway at JPL to reprocess historical VLBI and GPS data to improve realizations of the terrestrial and celestial frames. Improvements include minimal constraint alignment, improved tropospheric modeling, better orbit determination, and corrections for antenna phase center patterns.

  12. A novel navigation method used in a ballistic missile

    International Nuclear Information System (INIS)

    The traditional strapdown inertial/celestial integrated navigation method used in a ballistic missile cannot accurately estimate the accelerometer bias. It might cause a divergence of navigation errors. To solve this problem, a new navigation method named strapdown inertial/starlight refractive celestial integrated navigation is proposed. To verify the feasibility of the proposed method, a simulated program of a ballistic missile is presented. The simulation results indicated that, when multiple refraction stars are used, the proposed method can accurately estimate the accelerometer bias, and suppress the divergence of navigation errors completely. Specifically, in order to apply this method to a ballistic missile, a novel measurement equation based on stellar refraction was developed. Furthermore a method to calculate the number of refraction stars observed by the stellar sensor was given. Finally, the relationship between the number of refraction stars used and the navigation accuracy is analysed. (paper)

  13. Deep Space CubeSat Gamma-ray Navigation Technology Demonstration Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed novel program will use measurements of high-energy photon output from celestial gamma-ray sources to design a new, unique navigation system for a deep...

  14. Gravitation and celestial mechanics investigations with Galileo

    Science.gov (United States)

    Anderson, J. D.; Armstrong, J. W.; Campbell, J. K.; Estabrook, F. B.; Krisher, T. P.; Lau, E. L.

    1992-01-01

    The gravitation and celestial mechanics investigations that are to be conducted during the cruise and Orbiter phases of the Galileo Mission cover four investigation categories: (1) the gravity fields of Jupiter and its four major satellites; (2) a search for gravitational radiation; (3) mathematical modeling of general relativistic effects on Doppler ranging data; and (4) improvements of the Jupiter ephemeris via Orbiter ranging. Also noted are two secondary objectives, involving a range fix during Venus flyby and the determination of the earth's mass on the bases of the two earth gravity assists used by the mission.

  15. Research career of an astronomer who has studied celestial mechanics

    Science.gov (United States)

    Kozai, Yoshihide

    2016-09-01

    Celestial mechanics has been a classical field of astronomy. Only a few astronomers were in this field and not so many papers on this subject had been published during the first half of the 20th century. However, as the beauty of classical dynamics and celestial mechanics attracted me very much, I decided to take celestial mechanics as my research subject and entered university, where a very famous professor of celestial mechanics was a member of the faculty. Then as artificial satellites were launched starting from October 1958, new topics were investigated in the field of celestial mechanics. Moreover, planetary rings, asteroids with moderate values of eccentricity, inclination and so on have become new fields of celestial mechanics. In fact I have tried to solve such problems in an analytical way. Finally, to understand what gravitation is I joined the TAMA300 gravitational wave detector group.

  16. MASER Navigation in the Milk Way and Intergalatic

    CERN Document Server

    Dong, Jiang

    2009-01-01

    The traditional celestial navigation system(CNS) is used the moon, stars, and planets as celestial guides. Then the star tracker(i.e. track one star or planet or angle between it) and star sensor(i.e. sense many star simultaneous) be used to determine the attitude of the spacecraft. Pulsar navigation also be introduced to CNS. Maser is another interested celestial in radio astronomy which has strong flux density as spectral line. Now I analysis the principle of maser navigation which base measure Doppler shift frequency spectra and the feasibility that use the exist instrument, and discuss the integrated navigation use maser, then give the perspective in the Milk Way and the intergalatic. Maser navigation can give the continuous position in deep space, that means we can freedom fly successfully in the Milk Way use celestial navigation that include maser, pulsar and traditional star sensor. Maser as nature beacon in the universe will make human freely fly in the space of the Milk Way, even outer of it. That is...

  17. The stratification of regolith on celestial objects

    CERN Document Server

    Schräpler, Rainer; von Borstel, Ingo; Güttler, Carsten

    2015-01-01

    All atmosphere-less planetary bodies are covered with a dust layer, the so-called regolith, which determines the optical, mechanical and thermal properties of their surface. These properties depend on the regolith material, the size distribution of the particles it consists of, and the porosity to which these particles are packed. We performed experiments in parabolic flights to determine the gravity dependency of the packing density of regolith for solid-particle sizes of 60 $\\mu$m and 1 mm as well as for 100-250 $\\mu$m-sized agglomerates of 1.5 $\\mu$m-sized solid grains. We utilized g-levels between 0.7 m s$^{-2}$ and 18 m s$^{-2}$ and completed our measurements with experiments under normal gravity conditions. Based on previous experimental and theoretical literature and supported by our new experiments, we developed an analytical model to calculate the regolith stratification of celestial rocky and icy bodies and estimated the mechanical yields of the regolith under the weight of an astronaut and a spacec...

  18. Celestial Reference Frames at Multiple Radio Wavelengths

    Science.gov (United States)

    Jacobs, Christopher S.

    2012-01-01

    In 1997 the IAU adopted the International Celestial Reference Frame (ICRF) built from S/X VLBI data. In response to IAU resolutions encouraging the extension of the ICRF to additional frequency bands, VLBI frames have been made at 24, 32, and 43 gigahertz. Meanwhile, the 8.4 gigahertz work has been greatly improved with the 2009 release of the ICRF-2. This paper discusses the motivations for extending the ICRF to these higher radio bands. Results to date will be summarized including evidence that the high frequency frames are rapidly approaching the accuracy of the 8.4 gigahertz ICRF-2. We discuss current limiting errors and prospects for the future accuracy of radio reference frames. We note that comparison of multiple radio frames is characterizing the frequency dependent systematic noise floor from extended source morphology and core shift. Finally, given Gaia's potential for high accuracy optical astrometry, we have simulated the precision of a radio-optical frame tie to be approximately10-15 microarcseconds ((1-sigma) (1-standard deviation), per component).

  19. Celestial shadows eclipses, transits, and occultations

    CERN Document Server

    Westfall, John

    2015-01-01

    Much of what is known about the universe comes from the study of celestial shadows—eclipses, transits, and occultations.  The most dramatic are total eclipses of the Sun, which constitute one of the most dramatic and awe-inspiring events of nature.  Though once a source of consternation or dread, solar eclipses now lead thousands of amateur astronomers and eclipse-chasers to travel to remote points on the globe to savor their beauty and the adrenaline-rush of experiencing totality, and were long the only source of information about the hauntingly beautiful chromosphere and corona of the Sun.   Long before Columbus, the curved shadow of the Earth on the Moon during a lunar eclipse revealed that we inhabit a round world. The rare and wonderful transits of Venus, which occur as it passes between the Earth and the Sun, inspired eighteenth century expeditions to measure the distance from the Earth to the Sun, while the recent transits of 2004 and 2012 were the most widely observed ever--and still produced re...

  20. Industrial Scale Production of Celestial Body Simulants Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The technical objectives of this program are to develop a cost-effective process to deliver Celestial body simulants for the foreseeable future. Specifically, the...

  1. Ancient Greek Tradition in Arabic and Christian Celestial Globes

    Czech Academy of Sciences Publication Activity Database

    Hadrava, Petr; Hadravová, Alena

    Campobasso : University of Molise, 2012 - (Badolati, E.), s. 77-85 ISBN 9788867350285. [Conference on Cultural Astronomy /3./. Campobasso (IT), 08.11.2011-08.11.2011] R&D Projects: GA ČR(CZ) GAP405/11/0034 Institutional support: RVO:67985815 ; RVO:68378114 Keywords : celestial globes * iconography of constellations Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics; AB - History (USD-C)

  2. Reconstruction of the celestial globe of the Ming Dynasty.

    Science.gov (United States)

    Xu, Zhengtao; Ling, Rongfu

    1997-09-01

    Four big bronze instruments were made in the seventh year of the Zhengtong reign of the Ming Dynasty (AD 1442). They are the Armillary Sphere, Abridged Armilla, Gnomon and Celestial Globe. The first three ones are well presented in the Purple Mountain Observatory. But the Celestial Globe was destroyed in the early period of the Qing Dynasty. According to the astronomical treatises of the Yuan and Ming Dynasty and related references the authors reconstructed this instrument in original size.

  3. NAVIGATOR (FER)

    International Nuclear Information System (INIS)

    The NAVIGATOR concept is based on the negative-ion-grounded 500 keV/20 MW neutral beam injection system (NBI system), which has been proposed and studied at JAERI. The NAVIGATOR concept contains two categories; one is the NAVIGATOR machine as a tokamak reactor, and the other is the NAVIGATOR philosphy as a quiding principle in fusion research. The NAVIGATOR concept should be applied in a phased approach to and beyond the operating goal for the FER (Fusion Experimental Reactor, the next generation tokamak machine in Japan). The mission of the FER is to realize self-ignition and a long controlled burn of about 800 seconds and to develop and test fusion technologies, including the tritiumfuel cycle, superconducting magnet, remote maintenance and breeding blanket test modules. The NAVIGATOR concept is composed of three major elements, that is, reliable operation scenarios, reliable maintenability and suffiecient flexibility of the reactor. The NAVIGATOR concept well supports the ideas of phased operation and phased construction of the FER, which will result in the reduction technological risk. (author). 4 refs.; 3 figs

  4. Ecodesign Navigator

    DEFF Research Database (Denmark)

    Simon, M; Evans, S.; McAloone, Timothy Charles; Sweatman, A.; Bhamra, T.; Poole, S.

    The Ecodesign Navigator is the product of a three-year research project called DEEDS - DEsign for Environment Decision Support. The initial partners were Manchester Metropolitan University, Cranfield University, Engineering 6 Physical Sciences Resaech Council, Electrolux, ICL, and the Industry...

  5. Dynamical Configurations of Celestial Systems Comprised of Multiple Irregular Bodies

    CERN Document Server

    Jiang, Yu; Baoyin, Hexi; Li, Junfeng

    2016-01-01

    This manuscript considers the main features of the nonlinear dynamics of multiple irregular celestial body systems. The gravitational potential, static electric potential, and magnetic potential are considered. Based on the three established potentials, we show that three conservative values exist for this system, including a Jacobi integral. The equilibrium conditions for the system are derived and their stability analyzed. The equilibrium conditions of a celestial system comprised of n irregular bodies are reduced to 12n minus 9 equations. The dynamical results are applied to simulate the motion of multiple-asteroid systems. The simulation is useful for the study of the stability of multiple irregular celestial body systems and for the design of spacecraft orbits to triple asteroid systems discovered in the solar system. The dynamical configurations of the five triple-asteroid systems 45 Eugenia, 87 Sylvia, 93 Minerva, 216 Kleopatra, and 136617 1994CC, and the six-body system 134340 Pluto are calculated and...

  6. Radio and optical realizations of celestial reference frames

    CERN Document Server

    Lambert, S B; Le Poncin-Lafitte, C; Barache, C; Souchay, J

    2006-01-01

    The International Celestial Reference Frame (ICRF, Ma et al. 1998) is currently the best realization of a quasi-inertial reference system. It is based on more than 10 years of cumulated geodetic and astrometric VLBI observations of compact extragalactic objects at centimetric wavelengths. In the perspective of the realization of an accurate optical counterpart of the ICRF using future space astrometry missions like GAIA or SIM, this paper investigates the consistency of celestial reference frames realized through the same subset of compact extragalactic radio sources at optical wavelengths. Celestial reference frames realized in radio wavelengths with the VLBA Calibrator Survey (VCS) data and in optical wavelengths with the Sloan Digital Sky Survey (SDSS) data (DR3 quasar catalogue and DR5) are compared in terms of radio-optical distances between the common sources, global rotation of the axes and offset of the equator.

  7. Pulsar Navigation in the Solar System

    CERN Document Server

    Dong, Jiang

    2008-01-01

    The X-ray Pulsar-based Autonomous Navigation(XNAV) were recently tested which use the Crab pulsar (PSR B0531+21) in the USA Experiment on flown by the Navy on the Air Force Advanced Research and Global Observation Satellite (ARGOS) under the Space Test Program. It provide the way that the spacecraft could autonomously determine its position with respect to an inertial origin. Now I analysis the sensitivity of the exist instrument and the signal process to use radio pulsar navigation and discuss the integrated navigation use pulsar,then give the different navigation mission analysis and design process basically which include the space, the airborne, the ship and the land of the planet or the lunar.So the pulsar navigation can give the continuous position in deep spaces, that means we can freedom fly successfully in the solar system use celestial navigation that include pulsar and traditional star sensor.It also can less or abolish the depend of Global Navigation Satellite System which include GPS, GRONSS, Gali...

  8. The GAOUA series of compiled celestial reference frames

    Science.gov (United States)

    Molotaj, O.; Tel'Nyuk-Adamchuk, V.; Yatskiv, Ya.

    2000-09-01

    The GAOUA series of compiled celestial reference frames is obtained by using the original Kyiv arc length approach for combination of initial RSC solutions which are yearly submitted to the IERS CB by various VLBI Analysis Centers. The presentation is concerned with an analysis of accuracies of these individual and combined solutions and that of the ICRF.

  9. Bias Estimations for Ill-posed Problem of Celestial Positioning Using the Sun and Precision Analysis

    Directory of Open Access Journals (Sweden)

    ZHAN Yinhu

    2016-08-01

    Full Text Available Lunar/Mars rovers own sun sensors for navigation, however, long-time tracking for the sun impacts on the real-time activity of navigation. Absolute positioning method by observing the sun with a super short tracking period such as 1 or 2 minutes is researched in this paper. Linear least squares model of altitude positioning method is deduced, and the ill-posed problem of celestial positioning using the sun is brought out for the first time. Singular value decomposition method is used to diagnose the ill-posed problem, and different bias estimations are employed and compared by simulative calculations. Results of the calculations indicate the superiority of bias estimations which can effectively improve initial values. However, bias estimations are greatly impacted by initial values, because the initial values converge at a line which passes by the real value and is vertical relative to the orientation of the sun. The research of this paper is of some value to application.

  10. Division a Commission 7: Celestial Mechanics and Dynamical Astronomy

    Science.gov (United States)

    Morbidelli, Alessandro; Beaugé, Cristian; Knežević, Zoran; Celetti, Alessandra; Haghighipour, Nader; Hut, Piet; Laskar, Jacques; Mikkola, Seppo; Roig, Fernando

    2016-04-01

    In order to mark a distinction with the traditional triennial reports, for this legacy issue we have asked our present and past OC members, as well as a few other outstanding members of the Celestial Mechanics community, to write a short essay on ``recent highlights and the future of Celestial Mechanics''. Below we collect the contributions of the people who responded to our invitation. As it is natural, each of them interpreted their task differently. Some produced a dissertation on broad and general aspects, others focused on a specific topic of their interest. Some considered that their role was to provide a detailed review, with a list of key references, others preferred to mention the topics for which progress has been significant but without quoting any references, implicitly considering that this progress was possible thanks to the collective efforts of many scientists, and not just a few. This is great, as we appreciate the diversity of attitudes and opinions.

  11. Arrival Directions of UHECR on the Celestial Sphere

    International Nuclear Information System (INIS)

    The arrival directions of ultrahigh energy extensive air showers (EAS) by Yakutsk, AGASA, P. Auger array data are analyzed. For the first time, the maps of equal exposition of celestial sphere for the distribution of particles by AGASA and P. Auger arrays data have been constructed. The large-scale anisotropy of cosmic particles at E >4.1019 eV by Yakutsk, AGASA and P. Auger array data has been detected. The problem of cosmic particle origin is discussed. (authors)

  12. The IAA Cosmic Study 'Protecting the Environment of Celestial Bodies'

    Science.gov (United States)

    Rettberg, Petra; Hofmann, Mahulena; Williamson, Mark

    The study group tasked with producing this International Academy of Astronautics (IAA) `Cosmic Study' on Protecting the Environment of Celestial Bodies was formed under the aus-pices of IAA Commission V (Space Policy, Law Economy). The members of the international, multidisciplinary team assembled to undertake the Study accept, as a premise, the Planetary Protection Policy guidelines developed by COSPAR, which differentiate the degree of protec-tion according to the type of space activity and the celestial body under investigation (such that fly-by missions have less stringent requirements than lander missions, while Mars is `better protected' than the Moon). However, this Study goes deliberately beyond the interpretation of `Planetary Protection' as a set of methods for protecting the planets from biological con-tamination and extends consideration to the geophysical, industrial and cultural realms. The Study concludes that, from the perspective of current and future activities in outer space, present measures aimed at protecting the space environment are insufficient. Deficiencies in-clude a lack of suitable in-situ methods of chemical and biological detection and the absence of a systematic record of radioactive contaminants. Other issues identified by the Study include an insufficient legal framework, a shortage of effective economic tools and a lack of political will to address these concerns. It is expected that new detection methods under development, and the resultant increase in microbiological knowledge of the planetary surfaces, will lead to changes in the COSPAR planetary protection guidelines and bioburden limits. It is important, however, that any new approaches should not hamper future exploration and exploitation of celestial bodies more than absolutely necessary. The Study addresses the need to find a balance between protection and freedom of action. From a legal perspective, the Study concludes that a general consensus on protection of the

  13. Electromagnetic spacecraft used for magnetic navigation within asteroid belt, mining concepts and asteroid magnetic classification

    Czech Academy of Sciences Publication Activity Database

    Kletetschka, Günther; Adachi, T.; Mikula, V.

    League City: Lunar and Planetary Institute, 2007 - (Mackwell, S.). Art. 1093-Art. 1093 [Lunar and Planetary Science /38./. 12.03.2007-16.03.2007, League City] Institutional research plan: CEZ:AV0Z30130516 Keywords : magnetic navigation * mining concepts * asteroid classification Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics

  14. Autonomous Spacecraft Navigation Based on Pulsar Timing Information

    CERN Document Server

    Bernhardt, Mike Georg; Prinz, Tobias; Breithuth, Ferdinand Maximilian; Walter, Ulrich

    2011-01-01

    We discuss the possibility of an autonomous navigation system for spacecraft that is based on pulsar timing data. Pulsars are rapidly rotating neutron stars that are observable as variable celestial sources of electromagnetic radiation. Their periodic signals have timing stabilities comparable to atomic clocks and provide characteristic temporal signatures that can be used as natural navigation beacons, quite similar to the use of GPS satellites for navigation on Earth. By comparing pulse arrival times measured on-board the spacecraft with predicted pulse arrivals at some reference location, the spacecraft position can be determined autonomously with accuracies on the order of 5 kilometres. For a spacecraft at a distance of 10 astronomical units from Earth (e.g., Earth-Saturn), this means an improvement by a factor of 8 compared to conventional methods. Therefore this new technology is an alternative to standard navigation based on radio tracking by ground stations, without the disadvantages of uncertainty in...

  15. Stability study of realization of the celestial reference frame

    Science.gov (United States)

    Yatskiv, Ya. S.; Bolotin, S. L.; Kur'yanova, A. N.

    2004-09-01

    We present a short overview of the activity of the IERS as well as the Main Astronomical Observatory (MAO) of the National Academy of Sciences of Ukraine for maintenance and extention of the International Celestial Reference Frame (ICRF). Special attention is given to the time stabilities of positions of radio sources (RS) and to the selection of a subset of RS to be used for maintenance of the ICRF. It is shown that seven RS qualified by the IERS as defining sources are unstable.

  16. Celestial reference frame RSC (GAOUA) 98 C 01.

    Science.gov (United States)

    Molotaj, O. A.; Tel'Nyuk-Adamchuk, V. V.; Yatskiv, Ya. S.

    The celestial reference frame RSC (GAOUA) 98 C 01 was constructed by applying the Kiev arc method to five initial frames submitted to the IERS during 1997. The frame comprises positions of 631 radio sources. The frame axes are aligned to those of the ICRF with an accuracy of 0.02 mas using all 212 defining common radio sources. The internal standard errors of right ascension and declination for the defining sources are equal to 0.11 and 0.13 mas, respectively. Results of intercomparison between the ICRF, five initial frames, and the compiled frame are discussed.

  17. Kepler-16 Circumbinary System Validates Quantum Celestial Mechanics

    Directory of Open Access Journals (Sweden)

    Potter F.

    2012-01-01

    Full Text Available We report the application of quantum celestial mechanics (QCM to the Kepler-16 cir- cumbinary system which has a single planet orbiting binary stars with the important system parameters known to within one percent. Other gravitationally bound systems such as the Solar System of planets and the Jovian satellite systems have large uncertain- ties in their total angular momentum. Therefore, Kepler-16 allows us for the first time to determine whether the QCM predicted angular momentum per mass quantization is valid.

  18. The Power of Stars How Celestial Observations Have Shaped Civilization

    CERN Document Server

    Penprase, Bryan E

    2011-01-01

    What are some of the connections that bind us to the stars? How have these connections been established? And how have people all around the world and throughout time reacted to the night sky, the sun and moon, in their poetry, mythology, rituals, and temples? This book explores the influence of the sky on both ancient and modern civilization, by providing a clear overview of the many ways in which humans have used the stars as an ordering principle in their cultures, and which today still inspire us intellectually, emotionally, and spiritually. The book explores constellation lore from around the world, celestial alignments of monuments and temples, both from ancient and modern civilizations, and the role the sky has played in the cultures of the Greek, Egyptian, Babylonian, Native American, Chinese, Mayan, Aztec, and Inca. Models of the universe from each of these cultures are described clearly, and each culture’s explanation of the stars, planets, and other celestial objects are described. The roots of as...

  19. GRAIL gravity field determination using the Celestial Mechanics Approach

    Science.gov (United States)

    Arnold, Daniel; Bertone, Stefano; Jäggi, Adrian; Beutler, Gerhard; Mervart, Leos

    2015-11-01

    The NASA mission GRAIL (Gravity Recovery and Interior Laboratory) inherited its concept from the GRACE (Gravity Recovery and Climate Experiment) mission to determine the gravity field of the Moon. We present lunar gravity fields based on the data of GRAIL's primary mission phase. Gravity field recovery is realized in the framework of the Celestial Mechanics Approach, using a development version of the Bernese GNSS Software along with Ka-band range-rate data series as observations and the GNI1B positions provided by NASA JPL as pseudo-observations. By comparing our results with the official level-2 GRAIL gravity field models we show that the lunar gravity field can be recovered with a high quality by adapting the Celestial Mechanics Approach, even when using pre-GRAIL gravity field models as a priori fields and when replacing sophisticated models of non-gravitational accelerations by appropriately spaced pseudo-stochastic pulses (i.e., instantaneous velocity changes). We present and evaluate two lunar gravity field solutions up to degree and order 200 - AIUB-GRL200A and AIUB-GRL200B. While the first solution uses no gravity field information beyond degree 200, the second is obtained by using the official GRAIL field GRGM900C up to degree and order 660 as a priori information. This reduces the omission errors and demonstrates the potential quality of our solution if we resolved the gravity field to higher degree.

  20. Navigation Lights - USACE IENC

    Data.gov (United States)

    Department of Homeland Security — These inland electronic Navigational charts (IENCs) were developed from available data used in maintenance of Navigation channels. Users of these IENCs should be...

  1. Surface Motion Relative to the Irregular Celestial Bodies

    CERN Document Server

    Jiang, Yu; Baoyin, Hexi

    2016-01-01

    We study the motion and equilibria of the grains on the surface of the irregular celestial body (hereafter called irregular bodies). Motions for the grains on the smooth and unsmooth surfaces are discussed, respectively. The linearized equations of motion relative to a surface equilibrium point and its characteristic equations are presented. Considering the stick-slip effect, the damping forces and the spring forces for the grain are calculated, then the linearized equations of motion and the characteristic equations relative to the surface equilibrium points are derived. The number of non-degenerate surface equilibria is an even number. We compute the motion of a grain released above three different regions relative to the irregular asteroid 6489 Golevka, including the flat surface, the concave region, and the convex region. Following the grain release and initial bounce, three kinds of motions exist, the orbital motion, the impact motion and the surface motion. We find that the maximum height of the next ho...

  2. Incontri celesti, vita del padre Clavio in cinque atti

    CERN Document Server

    Sigismondi, Costantino

    2011-01-01

    The year 2012 will be the fourth centennial year of the Jesuit Christopher Clavius (1535-1612), known as the Euclid of XVI century and the collaborator of the Pope Gregory XIII for the calendar reformation. In the occasion of the year of astronomy I wrote a short theatre pi\\`ece "Celestial encounters" dedicated to the life of Ft. Clavius. He observed two total eclipses from centreline in 1560 in Coimbra and in 1567 in Rome, a fact which is remarkable even for contemporary astronomers. The story is developed around those trips: scientific and religious motivations are put in evidence with historical and fantasy, but realistic, facts. An interregional project between Switzerland and Italy, dedicated to the development of high resolution CMOS camera for astronomy and medical sciences has been entitled to Clavius and will produce high resolution measurements of solar diameter.

  3. The Pleiades: the celestial herd of ancient timekeepers

    CERN Document Server

    Sparavigna, Amelia

    2008-01-01

    In the ancient Egypt seven goddesses, represented by seven cows, composed the celestial herd that provides the nourishment to her worshippers. This herd is observed in the sky as a group of stars, the Pleiades, close to Aldebaran, the main star in the Taurus constellation. For many ancient populations, Pleiades were relevant stars and their rising was marked as a special time of the year. In this paper, we will discuss the presence of these stars in ancient cultures. Moreover, we will report some results of archeoastronomy on the role for timekeeping of these stars, results which show that for hunter-gatherers at Palaeolithic times, they were linked to the seasonal cycles of aurochs.

  4. Commission 7: Celestial Mechanics and Dynamical Astronomy. Triennial Report 2006-2009

    Czech Academy of Sciences Publication Activity Database

    Burns, J.A.; Kneževic, Z.; Milani, A.; Vokrouhlický, D.; Athanassoula, E.; Beaugé, C.; Erdi, B.; Lemaitre, A.; Maciejewski, A.; Malhotra, R.; Morbidelli, A.; Peale, S.J.; Šidlichovský, Miloš; Zhou, J.-L.

    Cambridge: Cambridge University Press, 2009 - (van der Hucht, K.), s. 12-22. (Proceedings of the IAU. IAU Transactions. 27A). ISBN 978-0-521-85605-8 Institutional research plan: CEZ:AV0Z10030501 Keywords : celestial mechanics * resonances * exoplanets Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics

  5. Universal navigation on smartphones

    CERN Document Server

    Karimi, Hassan A

    2011-01-01

    Universal navigation is accessible primarily through smart phones providing users with navigation information regardless of the environment (i.e., outdoor or indoor). ""Universal Navigation for Smart Phones"" provide the most up-to-date navigation technologies and systems for both outdoor and indoor navigation. It also provides a comparison of the similarities and differences between outdoor and indoor navigation systems from both a technological stand point and user's perspective. All aspects of navigation systems including geo-positioning, wireless communication, databases, and functions wil

  6. Navigation in surgery

    OpenAIRE

    Mezger, Uli; Jendrewski, Claudia; Bartels, Michael

    2013-01-01

    Introduction “Navigation in surgery” spans a broad area, which, depending on the clinical challenge, can have different meanings. Over the past decade, navigation in surgery has evolved beyond imaging modalities and bulky systems into the rich networking of the cloud or devices that are pocket-sized. Discussion This article will review various aspects of navigation in the operating room and beyond. This includes a short history of navigation, the evolution of surgical navigation, as well as t...

  7. Apollo Onboard Navigation Techniques

    Science.gov (United States)

    Interbartolo, Michael

    2009-01-01

    This viewgraph presentation reviews basic navigation concepts, describes coordinate systems and identifies attitude determination techniques including Primary Guidance, Navigation and Control System (PGNCS) IMU management and Command and Service Module Stabilization and Control System/Lunar Module (LM) Abort Guidance System (AGS) attitude management. The presentation also identifies state vector determination techniques, including PGNCS coasting flight navigation, PGNCS powered flight navigation and LM AGS navigation.

  8. Infrasound and the avian navigational map

    Science.gov (United States)

    Hagstrum, J.T.

    2001-01-01

    Birds can accurately navigate over hundreds to thousands of kilometres, and use celestial and magnetic compass senses to orient their flight. How birds determine their location in order to select the correct homeward bearing (map sense) remains controversial, and has been attributed to their olfactory or magnetic senses. Pigeons can hear infrasound down to 0??05 Hz, and an acoustic avian map is proposed consisting of infrasonic cues radiated from steep-sided topographic features. The source of these infrasonic signals is microseisms continuously generated by interfering oceanic waves. Atmospheric processes affecting the infrasonic map cues can explain perplexing experimental results from pigeon releases. Moreover, four recent disrupted pigeon races in Europe and the north-eastern USA intersected infrasonic shock waves from the Concorde supersonic transport. Having an acoustic map might also allow clock-shifted birds to test their homeward progress and select between their magnetic and solar compasses.

  9. On transformation between international celestial and terrestrial reference systems

    Science.gov (United States)

    Bretagnon, P.; Brumberg, V. A.

    2003-09-01

    Based on the current IAU hierarchy of the relativistic reference systems, practical formulae for the transformation between barycentric (BCRS) and geocentric (GCRS) celestial reference systems are derived. BCRS is used to refer to ICRS, International Celestial Reference System. This transformation is given in four versions, dependent on the time arguments used for BCRS (TCB or TDB) and for GCRS (TCG or TT). All quantities involved in these formulae have been tabulated with the use of the VSOP theories (IMCCE theories of motion of the major planets). In particular, these formulae may be applied to account for the indirect relativistic third-body perturbations in motion of Earth's satellites and Earth's rotation problem. We propose to use the SMART theory (IMCCE theory of Earth's rotation) in constructing the Newtonian three-dimensional spatial rotation transformation between GCRS and ITRS, the International Terrestrial Reference System. This transformation is compared with two other versions involving extra angular variables currently used by IERS, the International Earth Rotation Service. It is shown that the comparison of these three forms of the same transformation may be greatly simplified by using the proposed composite rotation formula. Tables 1-20 of Appendix B containing the initial terms of the VSOP-based series for the BCRSGCRS transformation are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/408/387. The work on ICRSGCRS transformation with the use of VSOP theories was done in February-March 2002 during the stay of the second author in IMCCE. The authors hoped to complete the second part concerning GCRSITRS transformation with the use of SMART theory in September 2002 during the visit of the first author to IAA. The grave disease of Pierre Bretagnon which tragically resulted in his death on November 17, 2002, did not permit us to complete this work

  10. Numeric calculation of celestial bodies with spreadsheet analysis

    Science.gov (United States)

    Koch, Alexander

    2016-04-01

    The motion of the planets and moons in our solar system can easily be calculated for any time by the Kepler laws of planetary motion. The Kepler laws are a special case of the gravitational law of Newton, especially if you consider more than two celestial bodies. Therefore it is more basic to calculate the motion by using the gravitational law. But the problem is, that by gravitational law it is not possible to calculate the state of motion with only one step of calculation. The motion has to be numerical calculated for many time intervalls. For this reason, spreadsheet analysis is helpful for students. Skills in programmes like Excel, Calc or Gnumeric are important in professional life and can easily be learnt by students. These programmes can help to calculate the complex motions with many intervalls. The more intervalls are used, the more exact are the calculated orbits. The sutdents will first get a quick course in Excel. After that they calculate with instructions the 2-D-coordinates of the orbits of Moon and Mars. Step by step the students are coding the formulae for calculating physical parameters like coordinates, force, acceleration and velocity. The project is limited to 4 weeks or 8 lessons. So the calcualtion will only include the calculation of one body around the central mass like Earth or Sun. The three-body problem can only be shortly discussed at the end of the project.

  11. Transit of Venus Culture: A Celestial Phenomenon Intrigues the Public

    Science.gov (United States)

    Bueter, Chuck

    2012-01-01

    When Jeremiah Horrocks first observed it in 1639, the transit of Venus was a desirable telescopic target because of its scientific value. By the next transit of Venus in 1761, though, the enlightened public also embraced it as a popular celestial phenomenon. Its stature elevated over the centuries, the transit of Venus has been featured in music, poetry, stamps, plays, books, and art. The June 2004 transit emerged as a surprising global sensation, as suggested by the search queries it generated. Google's Zeitgeist deemed Venus Transit to be the #1 Most Popular Event in the world for that month. New priorities, technologies, and media have brought new audiences to the rare alignment. As the 2012 transit of Venus approaches, the trend continues with publicly accessible capabilities that did not exist only eight years prior. For example, sites from which historic observations have been made are plotted and readily available on Google Earth. A transit of Venus phone app in development will, if fully funded, facilitate a global effort to recreate historic expeditions by allowing smartphone users to submit their observed transit timings to a database for quantifying the Astronomical Unit. While maintaining relevance in modern scientific applications, the transit of Venus has emerged as a cultural attraction that briefly intrigues the mainstream public and inspires their active participation in the spectacle.

  12. Interaction Between the Celestial and the Terrestrial Reference Frames

    Science.gov (United States)

    Gordon, David; MacMillan, Dan; Bolotin, Sergei; Le Bail, Karine; Gipson, John; Ma, Chopo

    2010-01-01

    Effects of International Celestial Reference Frame (ICRF2) on the Terrestrial Reference Frames (TRF), CRF and EOP's, The ICRF2 became official on Jan. 1, 2010. It includes positions of 3414 compact radio astronomical sources observed with VLBI, a fivefold increase from the first ICRF. Numerous new VLBI models were used and the most unstable sources were treated as arc parameters to avoid distortions of the frame. The ICRF2 has a noise floor of 40 micro-arc-seconds and an axis stability of 10 micro-arc-seconds. It was aligned with the ICRS using 138 stable sources common to ICRF2 and ICRF-Ext2. Maintenance of ICRF2 is to be made using 295 defining sources chosen for their historical positional stability, minimal source structure, and sky distribution. Their stability and their more uniform sky distribution eliminate the two largest weaknesses of ICRF I. The switchover to ICRF2 has some small effects on the TRF, CRF and Earth Orientation Parameters (EOP). A CRF based on ICRF2 shows a relative rotation of 40 micro-arc-seconds, mostly about the Y-axis. Small shifts are also seen in the EOP's, the largest being 11 micro-arc-seconds in X-pole. Some small but insignificant differences are also seen in the TRF. These results will be presented and discussed.

  13. X/Ka Celestial Frame Improvements: Vision to Reality

    Science.gov (United States)

    Jacobs, C. S.; Bagri, D. S.; Britcliffe, M. J.; Clark, J. E.; Franco, M. M.; Garcia-Miro, C.; Goodhart, C. E.; Horiuchi, S.; Lowe, S. T.; Moll, V. E.; Navarro, R.; Rogstad, S. P.; Proctor, R. C.; Sigman, E. H.; Skjerve, L. J.; Soriano, M. A.; Sovers, O. J.; Tucker, B. C.; Wang, D.; White, L. A.

    2010-01-01

    In order to extend the International Celestial Reference Frame from its S/X-band (2.3/8.4 GHz) basis to a complementary frame at X/Ka-band (8.4/32 GHz), we began in mid-2005 an ongoing series of X/Ka observations using NASA s Deep Space Network (DSN) radio telescopes. Over the course of 47 sessions, we have detected 351 extra-galactic radio sources covering the full 24 hours of right ascension and declinations down to -45 degrees. Angular source position accuracy is at the part-per-billion level. We developed an error budget which shows that the main errors arise from limited sensitivity, mismodeling of the troposphere, uncalibrated instrumental effects, and the lack of a southern baseline. Recent work has improved sensitivity by improving pointing calibrations and by increasing the data rate four-fold. Troposphere calibration has been demonstrated at the mm-level. Construction of instrumental phase calibrators and new digital baseband filtering electronics began in recent months. We will discuss the expected effect of these improvements on the X/Ka frame.

  14. Optical Navigation System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposal is for a flexible navigation system for deep space operations that does not require GPS measurements. The navigation solution is computed using an...

  15. Dynamics of a Tether System Connected to an Irregularly Shaped Celestial Body

    Science.gov (United States)

    Jalali Mashayekhi, Mohammad; K. Misra, Arun; Keshmiri, Mehdi

    2016-04-01

    The problem of pendular oscillations of a tether attached to an irregularly shaped celestial body is studied in this paper. The dynamic analysis of the system is performed by examining the phase plane trajectories. The effect of the tether length as well as the higher order terms in the gravitational potential of the celestial body on the tether dynamics is investigated. It is demonstrated that consideration of the finite size of the celestial body can have significant effects on the tether dynamics, while the effect of the asphericity of the celestial body on the tether dynamics is negligible. This study is of practical relevance for asteroid deflection using tethers, as well as for the development of space elevators on small planets/moons.

  16. On the nomenclature of celestial objects - not to build the Tower of Babel.

    Science.gov (United States)

    Nishimura, S.

    In order to accumulate and retrieve data relating to celestial objects, it is essential to designate names of objects correctly. The recommendation by the IAU Working Group on the Nomenclature is described.

  17. Radar and electronic navigation

    CERN Document Server

    Sonnenberg, G J

    2013-01-01

    Radar and Electronic Navigation, Sixth Edition discusses radar in marine navigation, underwater navigational aids, direction finding, the Decca navigator system, and the Omega system. The book also describes the Loran system for position fixing, the navy navigation satellite system, and the global positioning system (GPS). It reviews the principles, operation, presentations, specifications, and uses of radar. It also describes GPS, a real time position-fixing system in three dimensions (longitude, latitude, altitude), plus velocity information with Universal Time Coordinated (UTC). It is accur

  18. Research on Web Navigations

    Directory of Open Access Journals (Sweden)

    Qian Zhongsheng

    2011-10-01

    Full Text Available Web applications employ various new languages, technologies, and programming models to implement applications with very high quality requirements. In building Web applications, three types of models must be considered, which are conceptual model, navigation model and presentation model. Navigation problems are significant among them that must be confronted. This work illuminates three different classifications of Web navigations as well as their feature, analyzes and compares various popular Web navigation models. Moreover, it also presents and suggests some guidelines for Web navigation design based on Web development design pattern experiences.

  19. SINS/CNS Nonlinear Integrated Navigation Algorithm for Hypersonic Vehicle

    Directory of Open Access Journals (Sweden)

    Yong-jun Yu

    2015-01-01

    Full Text Available Celestial Navigation System (CNS has characteristics of accurate orientation and strong autonomy and has been widely used in Hypersonic Vehicle. Since the CNS location and orientation mainly depend upon the inertial reference that contains errors caused by gyro drifts and other error factors, traditional Strap-down Inertial Navigation System (SINS/CNS positioning algorithm setting the position error between SINS and CNS as measurement is not effective. The model of altitude azimuth, platform error angles, and horizontal position is designed, and the SINS/CNS tightly integrated algorithm is designed, in which CNS altitude azimuth is set as measurement information. GPF (Gaussian particle filter is introduced to solve the problem of nonlinear filtering. The results of simulation show that the precision of SINS/CNS algorithm which reaches 130 m using three stars is improved effectively.

  20. Dawes Review 5: Australian Aboriginal Astronomy and Navigation

    CERN Document Server

    Norris, Ray P

    2016-01-01

    The traditional cultures of Aboriginal Australians include a significant astronomical component, perpetuated through oral tradition, ceremony, and art. This astronomical knowledge includes a deep understanding of the motion of objects in the sky, which was used for practical purposes such as constructing calendars and for navigation. There is also evidence that traditional Aboriginal Australians made careful records and measurements of cyclical phenomena, recorded unexpected phenomena such as eclipses and meteorite impacts, and could determine the cardinal points to an accuracy of a few degrees. Putative explanations of celestial phenomena appear throughout the oral record, suggesting traditional Aborig- inal Australians sought to understand the natural world around them, in the same way as modern scientists, but within their own cultural context. There is also a growing body of evidence for sophisticated navigational skills, including the use of astronomically based songlines. Songlines are effectively oral ...

  1. Kilohoku Ho`okele Wa`a : Astronomy of the Hawaiian Navigators

    Science.gov (United States)

    Slater, Stephanie; Slater, Timothy F.; Baybayan, Kalepa C.

    2016-01-01

    This poster provides an introduction to the astronomy of the Hawaiian wayfinders, Kilohoku Ho`okele Wa`a. Rooted in a legacy of navigation across the Polynesian triangle, wayfinding astronomy has been part of a suite of skills that allows navigators to deliberately hop between the small islands of the Pacific, for thousands of years. Forty years ago, in one manifestation of the Hawaiian Renaissance, our teachers demonstrated that ancient Hawaiians were capable of traversing the wide Pacific to settle and trade on islands separated by thousands of miles. Today those same mentors train a new generation of navigators, making Hawaiian voyaging a living, evolving, sustainable endeavor. This poster presents two components of astronomical knowledge that all crewmen, but particularly those in training to become navigators, learn early in their training. Na Ohana Hoku, the Hawaiian Star Families constitute the basic units of the Hawaiian sky. In contrast to the Western system of 88 constellations, Na Ohana Hoku divides the sky into four sections that each run from the northern to the southern poles. This configuration reduces cognitive load, allowing the navigator to preserve working memory for other complex tasks. In addition, these configurations of stars support the navigator in finding and generatively using hundreds of individual, and navigationally important pairs of stars. The Hawaiian Star Compass divides the celestial sphere into a directional system that uses 32 rather than 8 cardinal points. Within the tropics, the rising and setting of celestial objects are consistent within the Hawaiian Star Compass, providing for extremely reliable direction finding. Together, Na Ohana Hoku and the Hawaiian Star Compass provide the tropical navigator with astronomical assistance that is not available to, and would have been unknown to Western navigators trained at higher latitudes.

  2. Navigating the Internet.

    OpenAIRE

    Powsner, S M; Roderer, N K

    1994-01-01

    Navigating any complex set of information resources requires tools for both browsing and searching. A number of tools are available today for using Internet resources, and more are being developed. This article reviews existing navigational tools, including two developed at the Yale University School of Medicine, and points out their strengths and weaknesses. A major shortcoming of the present Internet navigation methods is the lack of controlled descriptions of the available resources. As a ...

  3. Indoor wayfinding and navigation

    CERN Document Server

    2015-01-01

    Due to the widespread use of navigation systems for wayfinding and navigation in the outdoors, researchers have devoted their efforts in recent years to designing navigation systems that can be used indoors. This book is a comprehensive guide to designing and building indoor wayfinding and navigation systems. It covers all types of feasible sensors (for example, Wi-Fi, A-GPS), discussing the level of accuracy, the types of map data needed, the data sources, and the techniques for providing routes and directions within structures.

  4. Quaternion regularization and trajectory motion control in celestial mechanics and astrodynamics: II

    Science.gov (United States)

    Chelnokov, Yu. N.

    2014-07-01

    Problems of regularization in celestial mechanics and astrodynamics are considered, and basic regular quaternion models for celestial mechanics and astrodynamics are presented. It is shown that the effectiveness of analytical studies and numerical solutions to boundary value problems of controlling the trajectory motion of spacecraft can be improved by using quaternion models of astrodynamics. In this second part of the paper, specific singularity-type features (division by zero) are considered. They result from using classical equations in angular variables (particularly in Euler variables) in celestial mechanics and astrodynamics and can be eliminated by using Euler (Rodrigues-Hamilton) parameters and Hamilton quaternions. Basic regular (in the above sense) quaternion models of celestial mechanics and astrodynamics are considered; these include equations of trajectory motion written in nonholonomic, orbital, and ideal moving trihedrals whose rotational motions are described by Euler parameters and quaternions of turn; and quaternion equations of instantaneous orbit orientation of a celestial body (spacecraft). New quaternion regular equations are derived for the perturbed three-dimensional two-body problem (spacecraft trajectory motion). These equations are constructed using ideal rectangular Hansen coordinates and quaternion variables, and they have additional advantages over those known for regular Kustaanheimo-Stiefel equations.

  5. Navigation Using Inertial Sensors

    OpenAIRE

    Groves, P. D.

    2015-01-01

    This tutorial provides an introduction to navigation using inertial sensors, explaining the underlying principles. Topics covered include accelerometer and gyro technology and their characteristics, strapdown inertial navigation, attitude determination, integration and alignment, zero updates, motion constraints, pedestrian dead reckoning using step detection, and fault detection.

  6. Methods of Celestial Mechanics Volume I: Physical, Mathematical, and Numerical Principles

    CERN Document Server

    Beutler, Gerhard

    2005-01-01

    G. Beutler's Methods of Celestial Mechanics is a coherent textbook for students in physics, mathematics and engineering as well as an excellent reference for practitioners. This Volume I gives a thorough treatment of celestial mechanics and presents all the necessary mathematical details that a professional would need. After a brief review of the history of celestial mechanics, the equations of motion (Newtonian and relativistic versions) are developed for planetary systems (N-body-problem), for artificial Earth satellites, and for extended bodies (which includes the problem of Earth and lunar rotation). Perturbation theory is outlined in an elementary way from generally known mathematical principles without making use of the advanced tools of analytical mechanics. The variational equations associated with orbital motion - of fundamental importance for parameter estimation (e.g., orbit determination), numerical error propagation, and stability considerations - are introduced and their properties discussed in ...

  7. Forecasting scenarios of collision catastrophes produced by celestial body falls

    Science.gov (United States)

    Shor, V.; Kochetova, O.; Chernetenko, Y.; Zheleznov, N.; Deryugin, V.; Zaitsev, A.

    2014-07-01

    The subject under discussion arose in the course of developing a computer program, which gives the possibility for numerical and graphical modeling of the scenarios of catastrophes caused by collisions of cosmic bodies with the Earth. It is expected that this program can be used for computer-assisted training of the personnel of units of the Ministry for Emergency Situations in the case of a situation caused by the fall of a celestial body on the Earth. Also, it is anticipated that the program can be used in real situations when a dangerous body is discovered on an orbit leading to an imminent collision with the Earth. From the scientific point of view, both variants of use require solving of analogous tasks. In what follows, we discuss both variants. 1. The computation of the circumstances for a fall on the Earth (or approach within short distance) of a real body begins with the determination of its orbit from the observations available using the least-squares method. The mean square error of the representation of the observations on the base of the initial values of the coordinates and the velocities is computed, as well as their covariance matrix. Then, the trajectory of the body's motion is followed by numerical integration starting from the osculating epoch to the collision with the Earth or to its flyby. The computer program takes into account the various cases: at the initial moment, the body can move away from or approach the Earth, it can be outside the sphere of action or inside it. At the moment, when the body enters the sphere of action, the coordinates of the center of the dispersion ellipse on the target plane are computed as well as the dimensions of its axes. Using these data, the probability of collision with the Earth is calculated. Then, the point of penetration of the body into the Earth's atmosphere at a given height above the level of the Earth geoid is determined. In case the body is passing by the Earth, the minimum distance of the body from

  8. Algorithms for vehicle navigation

    OpenAIRE

    Storandt, Sabine

    2012-01-01

    Nowadays, navigation systems are integral parts of most cars. They allow the user to drive to a preselected destination on the shortest or quickest path by giving turn-by-turn directions. To fulfil this task the navigation system must be aware of the current position of the vehicle at any time, and has to compute the optimal route to the destination on that basis. Both of these subproblems have to be solved frequently, because the navigation system must react immediately if the vehicle leaves...

  9. Restricted Navigation Areas - USACE IENC

    Data.gov (United States)

    Department of Homeland Security — These inland electronic Navigational charts (IENCs) were developed from available data used in maintenance of Navigation channels. Users of these IENCs should be...

  10. Spatial cognition and navigation

    Science.gov (United States)

    Aretz, Anthony J.

    1989-01-01

    An experiment that provides data for the development of a cognitive model of pilot flight navigation is described. The experiment characterizes navigational awareness as the mental alignment of two frames of reference: (1) the ego centered reference frame that is established by the forward view out of the cockpit and (2) the world centered reference frame that is established by the aircraft's location on a map. The data support a model involving at least two components: (1) the perceptual encoding of the navigational landmarks and (2) the mental rotation of the map's world reference frame into alignment with the ego centered reference frame. The quantitative relationships of these two factors are provided as possible inputs for a computational model of spatial cognition during flight navigation.

  11. Illustrating the phaenomena celestial cartography in antiquity and the Middle Ages

    CERN Document Server

    Dekker, Elly

    2013-01-01

    In this volume all extant celestial maps and globes made before 1500 are described and analysed. It also discusses the astronomical sources involved in making these artefacts in antiquity, the Middle Ages, the Islamic world and the European Renaissance before 1500.

  12. Vladimir I Arnold - Collected Works Representations of Functions, Celestial Mechanics, and KAM Theory 1957-1965

    CERN Document Server

    Arnold, Vladimir I; Khesin, Boris

    2010-01-01

    Vladimir Arnold is one of the great mathematical scientists of our time. He is famous for both the breadth and the depth of his work. At the same time he is one of the most prolific and outstanding mathematical authors. This first volume of his Collected Works focuses on representations of functions, celestial mechanics, and KAM theory.

  13. The arrival direction of (4/3)e-lepton candidates in celestial coordinates

    International Nuclear Information System (INIS)

    A cosmic-ray counter telescope (OKAYAMA telescope) has been operated at several zenith angles at sea level. Several millions of clean single events have been analysed. About thirty candidates of (4/3)e charged leptons were found at around 40 zenith angles. The distribution of the arrival directions of these candidates in the celestial sphere was found to be anisotropic

  14. Quaternion regularization in celestial mechanics and astrodynamics and trajectory motion control. I

    Science.gov (United States)

    Chelnokov, Yu. N.

    2013-09-01

    Regularization problems in celestial mechanics and astrodynamics are considered. The fundamental regular quaternion models of celestial mechanics and astrodynamics are presented. It is shown that the efficiency of analytical investigation and numerical solution of boundary problems of optimal trajectory motion control of spacecraft may be increased using quaternion astrodynamics models. The regularization problem of celestial mechanics and astrodynamics that implies eliminating the feature, which arises in the equations of the two-body problem in case of impact of the second body with the central body, is considered in the first section of the paper. The quaternion method for regularizing the equations of the perturbed spatial two-body problem suggested by the author is presented; the method is compared with Kustaanheimo-Stiefel (KS) regularization. Demonstrative geometric and kinematic interpretations of regularizing transformations are provided. Regular quaternion equations for the two-body problem, which generalize the regular Kustaanheimo-Stiefel equations, as well as regular equations in quaternion osculating elements and quaternion regular equations for perturbed central motion of a material point, are considered. The papers on quaternion regularization in celestial mechanics and astrodynamics are briefly analyzed.

  15. The Gravitational Effects of a Celestial Body with Magnetic Charge and Moment

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The gravitational effects (precession of charge-less particles and deflection of light) in the gravitational field of a celestial body with magnetic charge and moment (CM)are investigated. We found that the magnetic charge always weakens the pure Schwarzschild effects, while the magnetic dipole moment deforms the effects in a more complicated way.

  16. Symmetric Synchronous Collaborative Navigation

    OpenAIRE

    Gerosa, Luca; Giordani, Alessandra; Ronchetti, Marco

    2004-01-01

    Synchronous collaborative navigation is a form of social navigation where users virtually share a web browser. In this paper, we present a symmetric, proxy-based architecture where each user can take the lead and guide others in visiting web sites, without the need for a special browser or other software. We show how we have applied this scheme to a problem-solving-oriented e-learning system.

  17. Processing Images of Craters for Spacecraft Navigation

    Science.gov (United States)

    Cheng, Yang; Johnson, Andrew E.; Matthies, Larry H.

    2009-01-01

    A crater-detection algorithm has been conceived to enable automation of what, heretofore, have been manual processes for utilizing images of craters on a celestial body as landmarks for navigating a spacecraft flying near or landing on that body. The images are acquired by an electronic camera aboard the spacecraft, then digitized, then processed by the algorithm, which consists mainly of the following steps: 1. Edges in an image detected and placed in a database. 2. Crater rim edges are selected from the edge database. 3. Edges that belong to the same crater are grouped together. 4. An ellipse is fitted to each group of crater edges. 5. Ellipses are refined directly in the image domain to reduce errors introduced in the detection of edges and fitting of ellipses. 6. The quality of each detected crater is evaluated. It is planned to utilize this algorithm as the basis of a computer program for automated, real-time, onboard processing of crater-image data. Experimental studies have led to the conclusion that this algorithm is capable of a detection rate >93 percent, a false-alarm rate <5 percent, a geometric error <0.5 pixel, and a position error <0.3 pixel.

  18. Beginnings of Satellite Navigation

    Directory of Open Access Journals (Sweden)

    Miljenko Solarić

    2008-05-01

    Full Text Available The first satellite navigation system called the Navy Navigation Satellite System (NNSS or TRANSIT was planned in the USA in 1958. It consisted of 5-6 artificial Earth satellites, was set in motion for the USA military in 1964, and in 1967 for civilian purposes. The frequency shift of received radio waves emitted from the satellite and caused by the Doppler effect was measured. The TRANSIT satellite speed of approaching or moving away was derived from that; the TRANSIT satellites emmited also their own coordinates. Then the ship's position was determined by an intersection of three hyperboloids, which were determined from differences of distances in three time intervals. Maintenance of this navigation system was stopped in 1996, but it is still being used in the USA Navy for exploring the ionosphere. Furthermore, results of Doppler measurements in international projects at the Hvar Observatory from 1982 and 1983. This was the first time in Croatia and the former country that the coordinates of the Hvar Observatory were determined in the unique world coordinate system WGS'72. The paper ends with a brief representation of the Tsiklon Doppler navigation system produced in the former Soviet Union, and there is a list of some of numerous produced and designed satellite navigation systems.Ključne riječi

  19. Coordinating sensing and local navigation

    Science.gov (United States)

    Slack, Marc G.

    1991-07-01

    Based on Navigation Templates (or NaTs), this work presents a new paradigm for local navigation which addresses the noisy and uncertain nature of sensor data. Rather than creating a new navigation plan each time the robot's perception of the world changes, the technique incorporates perceptual changes directly into the existing navigation plan. In this way, the robot's navigation plan is quickly and continuously modified, resulting in actions that remain coordinated with its changing perception of the world.

  20. Dawes Review 5: Australian Aboriginal Astronomy and Navigation

    Science.gov (United States)

    Norris, Ray P.

    2016-08-01

    The traditional cultures of Aboriginal Australians include a significant astronomical component, perpetuated through oral tradition, ceremony, and art. This astronomical knowledge includes a deep understanding of the motion of objects in the sky, which was used for practical purposes such as constructing calendars and for navigation. There is also evidence that traditional Aboriginal Australians made careful records and measurements of cyclical phenomena, recorded unexpected phenomena such as eclipses and meteorite impacts, and could determine the cardinal points to an accuracy of a few degrees. Putative explanations of celestial phenomena appear throughout the oral record, suggesting traditional Aboriginal Australians sought to understand the natural world around them, in the same way as modern scientists, but within their own cultural context. There is also a growing body of evidence for sophisticated navigational skills, including the use of astronomically based songlines. Songlines are effectively oral maps of the landscape, and are an efficient way of transmitting oral navigational skills in cultures that do not have a written language. The study of Aboriginal astronomy has had an impact extending beyond mere academic curiosity, facilitating cross-cultural understanding, demonstrating the intimate links between science and culture, and helping students to engage with science.

  1. Mobile Robot Navigation

    DEFF Research Database (Denmark)

    Andersen, Jens Christian

    2007-01-01

    . The research is now progressing towards autonomous robots which will be able to assist us in our daily life. One of the enabling technologies is navigation, and navigation is the subject of this thesis. Navigation of an autonomous robot is concerned with the ability of the robot to direct itself from...... validation of the implemented solutions and the ability of the methods to solve real world problems. The amount of software needed by an autonomous robot can be overwhelming. Software reuse and distributed development are therefore important issues. The thesis describes a new component architecture......Abstract Robots will soon take part in everyone’s daily life. In industrial production this has been the case for many years, but up to now the use of mobile robots has been limited to a few and isolated applications like lawn mowing, surveillance, agricultural production and military applications...

  2. Navigating Distributed Services

    DEFF Research Database (Denmark)

    Beute, Berco

    2002-01-01

    , to a situation where they are distributedacross the Internet. The second trend is the shift from a virtual environment that solelyconsists of distributed documents to a virtual environment that consists of bothdistributed documents and distributed services. The third and final trend is theincreasing...... diversity of devices used to access information on the Internet.The focal point of the thesis is an initial exploration of the effects of the trends onusers as they navigate the virtual environment of distributed documents and services.To begin the thesis uses scenarios as a heuristic device to identify and...... analyse themain effects of the trends. This is followed by an exploration of theory of navigationInformation Spaces, which is in turn followed by an overview of theories, and the stateof the art in navigating distributed services. These explorations of both theory andpractice resulted in a large number of...

  3. Mariner 9 navigation

    Science.gov (United States)

    Neil, W. J.; Jordan, J. F.; Zielenbach, J. W.; Wong, S. K.; Mitchell, R. T.; Webb, W. A.; Koskela, P. E.

    1973-01-01

    A final, comprehensive description of the navigation of Mariner 9-the first U.S. spacecraft to orbit another planet is provided. The Mariner 9 navigation function included not only precision flight path control but also pointing of the spacecraft's scientific instruments mounted on a two degree of freedom scan platform. To the extent appropriate, each section describes the perflight analyses on which the operational strategies and performance predictions were based. Inflight results are then discussed and compared with the preflight predictions. Postflight analyses, which were primarily concerned with developing a thorough understanding of unexpected in-flight results, are also presented.

  4. The attack navigator

    DEFF Research Database (Denmark)

    Probst, Christian W.; Willemson, Jan; Pieters, Wolter

    2016-01-01

    The need to assess security and take protection decisions is at least as old as our civilisation. However, the complexity and development speed of our interconnected technical systems have surpassed our capacity to imagine and evaluate risk scenarios. This holds in particular for risks that are...... caused by the strategic behaviour of adversaries. Therefore, technology-supported methods are needed to help us identify and manage these risks. In this paper, we describe the attack navigator: a graph-based approach to security risk assessment inspired by navigation systems. Based on maps of a socio...

  5. Kaluza-Klein bubble like structure and celestial sphere in inflationary universe

    CERN Document Server

    Shiromizu, T; Uchida, Y; Mukohyama, S; Shiromizu, Tetsuya; Tomizawa, Shinya; Uchida, Yuki; Mukohyama, Shinji

    2004-01-01

    We consider five dimensional deSitter spacetimes with a deficit angle due to the presence of a closed 2-brane and identify one dimension as an extra dimension. From the four dimensional viewpoint we can see that the spacetime has a structure similar to a Kaluza-Klein bubble of nothing, that is, four dimensional spacetime ends at the 2-brane. Since a spatial section of the full deSitter spacetime has the topology of a sphere, the boundary surface surrounds the remaining four dimensional spacetime, and can be considered as the celestial sphere. After the spacetime is created from nothing via an instanton which we describe, some four dimensional observers in it see the celestial sphere falling down, and will be in contact with a 2-brane attached on it.

  6. [The celestial phenomena in A. Dürer's engraving Melancholia I].

    Science.gov (United States)

    Weitzel, Hans

    2009-01-01

    The celestial body of Dürer's engraving Melencolia I is connected with his painting of a meteor, the Raveningham-painting; it is shown that the origin of this painting owns to the impact of the meteor of Ensisheim in 1492. Until now the celestial body, the balance, and the magic square are nearly consistently interpreted as the planet Saturn, the zodiac sign Libra, and the planet Jupiter, and the melancholy woman is subject to these heavenly bodies. Consequently, neoplatonic astrology has been the main focus of the engraving; including the rainbow, the engraving has also been interpreted biblically. The present paper, however, places emphasis on problems of the geometry as the reason of melancholy. Any astronomical meaning of the configuration of the numbers of the magic square is discarded. PMID:20336927

  7. Teaching Celestial Motions in Astronomy 101 using the Digital Fulldome Planetarium Environment

    Science.gov (United States)

    Balonek, Thomas J.; Eakin, J.

    2012-01-01

    We utilize the immersive fulldome digital planetarium capabilities of the Colgate University Ho Tung Visualization Laboratory (VisLab) in introductory astronomy courses to teach students about observable celestial motions. We are developing demonstrations and exercises in which students conduct realistic "observations" in the VisLab that complement observations that they make outside on clear nights. From these observations students determine the characteristics and time scales of motions of the various solar system objects. Using the VisLab it is possible for the students to observe the daily, monthly, annual and peculiar motions of the stars, Sun, Moon and planets that they would otherwise be unable to witness during the semester. Our "observation first" approach is to have students observe the various cycles of the sky early in the semester, and later explain the reasons for these motions when they learn about the historical developments in our understanding of the celestial motions.

  8. The use of small x-ray detectors for deep space relative navigation

    Science.gov (United States)

    Doyle, Patrick T.; Gebre-Egziabher, Demoz; Sheikh, Suneel I.

    2012-10-01

    Currently, there is considerable interest in developing technologies that will allow the use of high-energy photon measurements from celestial X-ray sources for deep space relative navigation. The impetus for this is to reduce operational costs in the number of envisioned space missions that will require spacecraft to have autonomous, or semiautonomous, navigation capabilities. For missions close to Earth, Global Navigation Satellite Systems (GNSS), such as the U.S. Global Positioning System (GPS), are readily available for use and provide high accuracy navigation solutions that can be used for autonomous vehicle operation. However, for missions far from Earth, currently only a few navigation options exist and most do not allow autonomous operation. While the radio telemetry based solutions with proven high performance such as NASA's Deep Space Network (DSN) can be used for these class of missions, latencies associated with servicing a fleet of vehicles, such as a constellation of communication or science observation spacecraft, may not be compatible with autonomous operations which require timely updates of navigation solutions. Thus, new alternative solutions are sought with DSN-like accuracy. Because of their highly predictable pulsations, pulsars emitting X-radiation are ideal candidates for this task. These stars are ubiquitous celestial sources that can be used to provide time, attitude, range, and range-rate measurements — key parameters for navigation. Laboratory modeling of pulsar signals and operational aspects such as identifying pulsar-spacecraft geometry and performing cooperative observations with data communication are addressed in this paper. Algorithms and simulation tools that will enable designing and analyzing X-ray navigation concepts for a cis-lunar operational scenario are presented. In this situation, a space vehicle with a large-sized X-ray detector will work cooperatively with a number of smaller vehicles with smaller-sized detectors to

  9. A Renaissance celestial globe as an analogue computer for determination of the coordinates on the heaven

    Science.gov (United States)

    Bartha, Lajos

    Around 1480 the Dominican astronomer and instrument maker Hans Dorn in Castle Buda (Budapest) built a copper celestial globe. This globe is a composite instrument, suited to mark the position of celestial bodies - - i.e. comets, planets, etc. - directly on the star-globe, and to locate the stars represented on the globe in the sky. The globe has a diameter of 39.5 cm and gives the fixed stars according to Ptolemy. The main circles are set in for the celestial equator and ecliptic. On the top of the vertical meridian circle (divided into 4 x 90^o) is a planispheric astrolabe on a strong perpendicular axis. On the reverse side of the astrolabe the altitude arcs can be set by a diopter. Two quadrants with arc-scales protrude downward in horseshoe shape, parallel to the globe, from the bottom of the astrolabe. The divided quadrants parallel to the disk of the astrolabe point to the horizontal 'calendar' disk of the globe and can be turned with the astrolabe to indicate the azimuth. When the globe is adjusted to a given instant of time, the position of a celestial body can be determined by turning the astrolabe and the diopter to the object. The quadrant then shows - with the 'calendar' disk and the quadrant's graduation seen parallel to the mater - the position on the globe either for a planet, a comet, or even a fixed star. Both globe and astrolabe enable one to fix the position of the heavenly bodies directly without the necessity of coordinate transformation. Father Dorn (Saxonia, ca.1425 - Vienna, after 1509) built the combined `analogue computer globe' for the court astrologer of the Hungarian King Matthias Corvinus, magister Martinus Olkusz z Bylica (also called Martinus Ilkusz). Today the globe is in the Museum of Collegium Maius at Cracow.

  10. OPTICAL SPECTRA OF CANDIDATE INTERNATIONAL CELESTIAL REFERENCE FRAME (ICRF) FLAT-SPECTRUM RADIO SOURCES

    Energy Technology Data Exchange (ETDEWEB)

    Titov, O.; Stanford, Laura M. [Geoscience Australia, P.O. Box 378, Canberra, ACT 2601 (Australia); Johnston, Helen M.; Hunstead, Richard W. [Sydney Institute for Astronomy, School of Physics, University of Sydney, NSW 2006 (Australia); Pursimo, T. [Nordic Optical Telescope, Nordic Optical Telescope Apartado 474E-38700 Santa Cruz de La Palma, Santa Cruz de Tenerife (Spain); Jauncey, David L. [CSIRO Astronomy and Space Science, ATNF and Research School of Astronomy and Astrophysics, Australian National University, Canberra, ACT 2611 (Australia); Maslennikov, K. [Central Astronomical Observatory at Pulkovo, Pulkovskoye Shosse, 65/1, 196140, St. Petersburg (Russian Federation); Boldycheva, A., E-mail: oleg.titov@ga.gov.au [Ioffe Physical Technical Institute, 26 Polytekhnicheskaya, St. Petersburg, 194021 (Russian Federation)

    2013-07-01

    Continuing our program of spectroscopic observations of International Celestial Reference Frame (ICRF) sources, we present redshifts for 120 quasars and radio galaxies. Data were obtained with five telescopes: the 3.58 m European Southern Observatory New Technology Telescope, the two 8.2 m Gemini telescopes, the 2.5 m Nordic Optical Telescope (NOT), and the 6.0 m Big Azimuthal Telescope of the Special Astrophysical Observatory in Russia. The targets were selected from the International VLBI Service for Geodesy and Astrometry candidate International Celestial Reference Catalog which forms part of an observational very long baseline interferometry (VLBI) program to strengthen the celestial reference frame. We obtained spectra of the potential optical counterparts of more than 150 compact flat-spectrum radio sources, and measured redshifts of 120 emission-line objects, together with 19 BL Lac objects. These identifications add significantly to the precise radio-optical frame tie to be undertaken by Gaia, due to be launched in 2013, and to the existing data available for analyzing source proper motions over the celestial sphere. We show that the distribution of redshifts for ICRF sources is consistent with the much larger sample drawn from Faint Images of the Radio Sky at Twenty cm (FIRST) and Sloan Digital Sky Survey, implying that the ultra-compact VLBI sources are not distinguished from the overall radio-loud quasar population. In addition, we obtained NOT spectra for five radio sources from the FIRST and NRAO VLA Sky Survey catalogs, selected on the basis of their red colors, which yielded three quasars with z > 4.

  11. From Celestial Empire to Nation State: Sport and the Origins of Chinese Nationalism (1840–1927)

    OpenAIRE

    Zhouxiang, Lu

    2010-01-01

    The history of the late Qing Dynasty and the early Republic clearly showed the close relationship between sport, nationalism and politics, and reflected the changes in Chinese society and Chinese people’s view of their identity as well as their way of thinking. Sport had a great importance, not only for the construction of Chinese nationalism and national consciousness, but also for the eventual transformation of China from a celestial empire into a modern nation state. It play...

  12. GPS INTEGRATED NAVIGATION SYSTEM

    Directory of Open Access Journals (Sweden)

    Swati R. Dhabarde

    2012-06-01

    Full Text Available In my project I am developing a computer program that willsimulate and explain the need of technology and advance systemfor any person moving or navigating in a car (or any vehicle.Every person in day to day life requires some navigation for theproper working of his work .it is the human nature that ever mantakes some guidance about some or another work without guidancethe job taken by a human being will be completed properly or notis not known. So, for a proper working of your decided scheduleyou should know everything about the place where you live. Youdo know and if you ought to know then you can use “EmergencyNavigation System”.‘Emergency Navigation System’ is specialized softwarewhich is able to track the current position (of any person drivingvehicles and tell the path and other detailed information aboutyour destination. If there are occurrences of multiple paths to thesame destination then it can show the shortest one among them.

  13. Influence of celestial light on lunar surface brightness determinations: Application to earthshine studies

    Science.gov (United States)

    Thejll, P.; Gleisner, H.; Flynn, C.

    2015-01-01

    Aims: We consider the influence of celestial-sphere brightness on determinations of terrestrial albedo from earthshine intensity measurements. In particular, the contributions from zodiacal light and starlight are considered. Methods: Using published data for the zodiacal light (ZL) and stellar brightness distribution across the sky, we calculate the expected contribution to the sky at the position of the Moon in typical earthshine observations, and the magnitude relative to typical earthshine intensities. We derive terrestrial albedo with and without the ZL correction in order to gauge the magnitude of the effect. Results: We find that celestial-sphere surface brightness can be so large that a considerable and unacceptable error level would have an impact on half of typical earthshine-based albedo-determinations if left unaccounted for. Considering the empirical uncertainty on ZL, we show that almost all our earthshine data can be used if a sky correction is made. In real observations we find up to a 1% effect on albedo results of correcting for the celestial brightness. Conclusions: Correction for ZL and starlight brightness is essential to earthshine measurements if climate-science relevant levels of terrestrial albedo accuracy are to be achieved, something that has not yet been realized. With ZL and starlight corrections the earthshine method can potentially yield accurate terrestrial albedo values.

  14. The Hands of the Pleiades: The Celestial Clock in the Classical Arabic Poetry of Dhū al-Rumma

    Science.gov (United States)

    Adams, W. B.

    2011-06-01

    In the desert poetry of Dhū al-Rumma (d. 117 AH/735 CE), astronomical phenomena sometimes function as familiar celestial timepieces that indicate the poetic timeframe literally and accurately. The literary, lexical, floral and astronomical analyses of a selection from this poetry illustrate the role of the Pleiades star cluster as a celestial clock and illuminate the utility of naked-eye astronomy in interpreting Arabic poetry of the early Islamic period.

  15. Inland Electronic Navigational Charts (IENC)

    Data.gov (United States)

    Army Corps of Engineers, Department of the Army, Department of Defense — These Inland Electronic Navigational Charts (IENCs) were developed from available data used in maintenance of Navigation channels. Users of these IENCs should be...

  16. Nautical Navigation Aids (NAVAID) Locations

    Data.gov (United States)

    Department of Homeland Security — Structures intended to assist a navigator to determine position or safe course, or to warn of dangers or obstructions to navigation. This dataset includes lights,...

  17. Risk of Adverse Health and Performance Effects of Celestial Dust Exposure

    Science.gov (United States)

    Scully, Robert R.; Meyers, Valerie E.

    2015-01-01

    Crew members can be directly exposed to celestial dust in several ways. After crew members perform extravehicular activities (EVAs), they may introduce into the habitat dust that will have collected on spacesuits and boots. Cleaning of the suits between EVAs and changing of the Environmental Control Life Support System filters are other operations that could result in direct exposure to celestial dusts. In addition, if the spacesuits used in exploration missions abrade the skin, as current EVA suits have, then contact with these wounds would provide a source of exposure. Further, if celestial dusts gain access to a suit's interior, as was the case during the Apollo missions, the dust could serve as an additional source of abrasions or enhance suit-induced injuries. When a crew leaves the surface of a celestial body and returns to microgravity, the dust that is introduced into the return vehicle will "float," thus increasing the opportunity for ocular and respiratory injury. Because the features of the respirable fraction of lunar dusts indicate they could be toxic to humans, NASA conducted several studies utilizing lunar dust simulants and authentic lunar dust to determine the unique properties of lunar dust that affect physiology, assess the dermal and ocular irritancy of the dust, and establish a permissible exposure limit for episodic exposure to airborne lunar dust during missions that would involve no more than 6 months stay on the lunar surface. Studies, with authentic lunar soils from both highland (Apollo 16) and mare (Apollo17) regions demonstrated that the lunar soil is highly abrasive to a high fidelity model of human skin. Studies of lunar dust returned during the Apollo 14 mission from an area of the moon in which the soils were comprised of mineral constituents from both major geological regions (highlands and mares regions) demonstrated only minimal ocular irritancy, and pulmonary toxicity that was less than the highly toxic terrestrial crystalline

  18. Navigation in Virtual Environment

    Czech Academy of Sciences Publication Activity Database

    Mikeš, Stanislav; Haindl, Michal; Holub, Radek

    Vienna: Austrian Computer Society, 2008 - (R. Sablatnig and J. Hemsley and P. Krammerer and E. Zolda and J. Stockinger), s. 111-118 ISBN 978-3-85403-238-0. [2nd International Conference EVA. Vienna (AT), 25.08.2008-28.08.2008] R&D Projects: GA AV ČR 1ET400750407; GA MŠk 1M0572; GA ČR GA102/08/0593 Grant ostatní: GA MŠk(CZ) 2C06019 Institutional research plan: CEZ:AV0Z10750506 Keywords : Virtual Reality * Navigation Subject RIV: BD - Theory of Information http://library.utia.cas.cz/separaty/2008/RO/mikes-haindl-holub-navigation%20in%20virtual%20environment.pdf

  19. Mobile Robot Navigation

    OpenAIRE

    Andersen, Jens Christian; Ravn, Ole; Andersen, Nils Axel

    2007-01-01

    Robotter vil om få år blive en del af vores daglige liv. Inden for produktionsindustrien har det allerede være tilfældet i mange år, men anvendelsen af mobile robotter har hidtil været henvist til isolerede områder som græsslåning, overvågning, landbrugsproduktion og militære funktioner. Fremskridt i forskningen gør, at robotter vil kunne assistere os i mange af vore daglige gøremål i en ikke så fjern fremtid. En af de teknologier, der skal gøre dette muligt, er navigation, og navigation er e...

  20. Self-navigating robot

    Science.gov (United States)

    Thompson, A. M.

    1978-01-01

    Rangefinding equipment and onboard navigation system determine best route from point to point. Research robot has two TV cameras and laser for scanning and mapping its environment. Path planner finds most direct, unobstructed route that requires minimum expenditure of energy. Distance is used as measure of energy expense, although other measures such as time or power consumption (which would depend on the topography of the path) may be used.

  1. Navigating stories in films

    OpenAIRE

    Salway, Andrew; Xu, Yan

    2005-01-01

    This report describes the transformation of feature films into hypervideo by representing their story structures using plot unties. Plot units represent cause-effect relationships between characters’ affect states and the events in a story. We use plot units to structure hypervideo links between intervals of video data. We have manually analysed two full-length feature films in terms of plot units. A system was developed to store and edit data about plot units and to navigate films by followi...

  2. Invisible Navigation (or Impossible?).

    OpenAIRE

    Özcan, Oğuzhan; O'Neil, Mary Lou

    2013-01-01

    Abstract: This article introduces an experimental artwork on moving mobile interfaces. It aims to answer the question: Is it possible to navigate a part of a large image composition, moving a smaller interface of a mobile device in a certain direction such as left and right, back and forth or up and down? The article then outlines the new concept of “Invisible (or impossible) Navigation” and discusses the output of artistic practices which address the “Labyrinth of Art”.

  3. Navigational Query Languages

    OpenAIRE

    Surinx, Dimitri

    2013-01-01

    In this thesis we introduce navigational query languages on graphs. Path queries in our languages are built over several operators: identity, union, composition, projection, coprojection, converse, transitive closure, diversity, intersection and difference. The smallest language we will consider only contains the first 3 operators, while the largest language contains all operators. For these query languages we will characterize their complete relative expressive power, i.e., we will compare t...

  4. Multisensor robot navigation system

    Science.gov (United States)

    Persa, Stelian; Jonker, Pieter P.

    2002-02-01

    Almost all robot navigation systems work indoors. Outdoor robot navigation systems offer the potential for new application areas. The biggest single obstacle to building effective robot navigation systems is the lack of accurate wide-area sensors for trackers that report the locations and orientations of objects in an environment. Active (sensor-emitter) tracking technologies require powered-device installation, limiting their use to prepared areas that are relative free of natural or man-made interference sources. The hybrid tracker combines rate gyros and accelerometers with compass and tilt orientation sensor and DGPS system. Sensor distortions, delays and drift required compensation to achieve good results. The measurements from sensors are fused together to compensate for each other's limitations. Analysis and experimental results demonstrate the system effectiveness. The paper presents a field experiment for a low-cost strapdown-IMU (Inertial Measurement Unit)/DGPS combination, with data processing for the determination of 2-D components of position (trajectory), velocity and heading. In the present approach we have neglected earth rotation and gravity variations, because of the poor gyroscope sensitivities of our low-cost ISA (Inertial Sensor Assembly) and because of the relatively small area of the trajectory. The scope of this experiment was to test the feasibility of an integrated DGPS/IMU system of this type and to develop a field evaluation procedure for such a combination.

  5. Navigation in virtual environments

    Science.gov (United States)

    Arthur, Erik; Hancock, Peter A.; Telke, Susan

    1996-06-01

    Virtual environments show great promise in the area of training. ALthough such synthetic environments project homeomorphic physical representations of real- world layouts, it is not known how individuals develop models to match such environments. To evaluate this process, the present experiment examined the accuracy of triadic representations of objects having learned them previously under different conditions. The layout consisted of four different colored spheres arranged on a flat plane. These objects could be viewed in either a free navigation virtual environment condition (NAV) or a single body position virtual environment condition. The first condition allowed active exploration of the environment while the latter condition allowed the participant only a passive opportunity to observe form a single viewpoint. These viewing conditions were a between-subject variable with ten participants randomly assigned to each condition. Performance was assessed by the response latency to judge the accuracy of a layout of three objects over different rotations. Results showed linear increases in response latency as the rotation angle increased from the initial perspective in SBP condition. The NAV condition did not show a similar effect of rotation angle. These results suggest that the spatial knowledge acquisition from virtual environments through navigation is similar to actual navigation.

  6. Integrated navigation method based on inertial navigation system and Lidar

    Science.gov (United States)

    Zhang, Xiaoyue; Shi, Haitao; Pan, Jianye; Zhang, Chunxi

    2016-04-01

    An integrated navigation method based on the inertial navigational system (INS) and Lidar was proposed for land navigation. Compared with the traditional integrated navigational method and dead reckoning (DR) method, the influence of the inertial measurement unit (IMU) scale factor and misalignment was considered in the new method. First, the influence of the IMU scale factor and misalignment on navigation accuracy was analyzed. Based on the analysis, the integrated system error model of INS and Lidar was established, in which the IMU scale factor and misalignment error states were included. Then the observability of IMU error states was analyzed. According to the results of the observability analysis, the integrated system was optimized. Finally, numerical simulation and a vehicle test were carried out to validate the availability and utility of the proposed INS/Lidar integrated navigational method. Compared with the test result of a traditional integrated navigation method and DR method, the proposed integrated navigational method could result in a higher navigation precision. Consequently, the IMU scale factor and misalignment error were effectively compensated by the proposed method and the new integrated navigational method is valid.

  7. On a celestial occurrence recorded in the hagiography of St. Vladimir

    Science.gov (United States)

    Banjević, Boris

    2002-04-01

    There were recorded a number of celestial occurrences in Serbian early history. Amongst them are a few appearances of comets. One except from Bible bearing on life of king David, relating to a phenomenon that might be interpreted as a comet, is in some way similar to the quotation from the hagiography of St. Vladimir. There is possibility that Halley's comet was observed at some time. This affects the chronology of the reign of St. Vladimir by about 11 years. This author thinks that it was in the summer 989 AD.

  8. The ICRF-3: Status, plans, and progress on the next generation International Celestial Reference Frame

    CERN Document Server

    Malkin, Z; Arias, F; Boboltz, D; Boehm, J; Bolotin, S; Bourda, G; Charlot, P; De Witt, A; Fey, A; Gaume, R; Heinkelmann, R; Lambert, S; Ma, C; Nothnagel, A; Seitz, M; Gordon, D; Skurikhina, E; Souchay, J; Titov, O

    2015-01-01

    The goal of this presentation is to report the latest progress in creation of the next generation of VLBI-based International Celestial Reference Frame, ICRF3. Two main directions of ICRF3 development are improvement of the S/X-band frame and extension of the ICRF to higher frequencies. Another important task of this work is the preparation for comparison of ICRF3 with the new generation optical frame GCRF expected by the end of the decade as a result of the Gaia mission.

  9. Micro-arcsecond Celestial Reference Frames: definition and realization — Impact of the recent IAU Resolutions

    International Nuclear Information System (INIS)

    The adoption of the International Celestial Reference System (ICRS), based on Very Long Baseline Interferometry (VLBI) observations of extragalactic radiosources by the International Astronomical Union (IAU) since 1998 January 1, opened a new era for astronomy. The ICRS and the corresponding frame, the International Celestial Reference Frame (ICRF), replaced the Fundamental Catalog (FK5) based on positions and proper motions of bright stars, with the Hipparcos catalog being adopted as the primary realization of the ICRS in optical wavelengths. According to its definition, the ICRS is such that the barycentric directions of distant extragalactic objects show no global rotation with respect to these objects; this provides a quasi-inertial reference for measuring the positions and angular motions of the celestial objects. Other resolutions on reference systems were passed by the IAU in 2000 and 2006 and endorsed by the International Union of Geodesy and Geophysics (IUGG) in 2003 and 2007, respectively. These especially concern the definition and realization of the astronomical reference systems in the framework of general relativity and transformations between them. First, the IAU 2000 resolutions refined the concepts and definition of the astronomical reference systems and parameters for Earth's rotation, and adopted the IAU 2000 precession-nutation. Then, the IAU 2006 resolutions adopted a new precession model that is consistent with dynamical theories; they also addressed definition, terminology or orientation issues relative to reference systems and time scales that needed to be specified after the adoption of the IAU 2000 resolutions. An additional IUGG 2007 resolution defined the International Terrestrial Reference System (ITRS) so that it strictly complies with the IAU recommendations. Finally, the IAU 2009 resolutions adopted a new system of astronomical constants and an improved realization of the ICRF. These fundamental changes have led to significant

  10. Micro-arcsecond Celestial Reference Frames: definition and realization - Impact of the recent IAU Resolutions

    Institute of Scientific and Technical Information of China (English)

    Nicole Capitaine

    2012-01-01

    The adoption of the International Celestial Reference System (ICRS),based on Very Long Baseline Interferometry (VLBI) observations of extragalactic radiosources by the International Astronomical Union (IAU) since 1998 January 1,opened a new era for astronomy.The ICRS and the corresponding frame,the International Celestial Reference Frame (ICRF),replaced the Fundamental Catalog (FK5) based on positions and proper motions of bright stars,with the Hipparcos catalog being adopted as the primary realization of the ICRS in optical wavelengths.According to its definition,the ICRS is such that the barycentric directions of distant extragalactic objects show no global rotation with respect to these objects; this provides a quasi-inertial reference for measuring the positions and angular motions of the celestial objects.Other resolutions on reference systems were passed by the IAU in 2000 and 2006 and endorsed by the International Union of Geodesy and Geophysics (IUGG) in 2003 and 2007,respectively.These especially concern the definition and realization of the astronomical reference systems in the framework of general relativity and transformations between them.First,the IAU 2000 resolutions refined the concepts and definition of the astronomical reference systems and parameters for Earth's rotation,and adopted the IAU 2000 precession-nutation.Then,the IAU 2006 resolutions adopted a new precession model that is consistent with dynamical theories; they also addressed definition,terminology or orientation issues relative to reference systems and time scales that needed to be specified after the adoption of the IAU 2000 resolutions.An additional IUGG 2007 resolution defined the International Terrestrial Reference System (ITRS) so that it strictly complies with the IAU recommendations.Finally,the IAU 2009 resolutions adopted a new system of astronomical constants and an improved realization of the ICRF.These fundamental changes have led to significant improvements in the fields

  11. Celestial Mechanics: from the bases of the past to the challenges of the future

    Science.gov (United States)

    de Melo, C. F.; Prado, A. F. B. A.; Macau, E. E. N.; Winter, O. C.; Gomes, V. M.

    2015-10-01

    This special issue of Journal of Physics: Conference Series brings a set of 31 papers presented in the Brazilian Colloquium on Orbital Dynamics (CBDO), held on December 1 - 5, 2014, in the city of Águas de Lindoia, Brazil. CBDO is a traditional and important scientific meeting in the areas of Theoretical and Applied Celestial Mechanics. The meeting takes place every two years, when researchers from South America and also guests from other continents present their works and discuss the paths trodden by the space sciences.

  12. 33 CFR 401.53 - Obstructing navigation.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Obstructing navigation. 401.53 Section 401.53 Navigation and Navigable Waters SAINT LAWRENCE SEAWAY DEVELOPMENT CORPORATION, DEPARTMENT OF TRANSPORTATION SEAWAY REGULATIONS AND RULES Regulations Seaway Navigation § 401.53...

  13. Control algorithms for autonomous robot navigation

    International Nuclear Information System (INIS)

    This paper examines control algorithm requirements for autonomous robot navigation outside laboratory environments. Three aspects of navigation are considered: navigation control in explored terrain, environment interactions with robot sensors, and navigation control in unanticipated situations. Major navigation methods are presented and relevance of traditional human learning theory is discussed. A new navigation technique linking graph theory and incidental learning is introduced

  14. Control algorithms for autonomous robot navigation

    Energy Technology Data Exchange (ETDEWEB)

    Jorgensen, C.C.

    1985-09-20

    This paper examines control algorithm requirements for autonomous robot navigation outside laboratory environments. Three aspects of navigation are considered: navigation control in explored terrain, environment interactions with robot sensors, and navigation control in unanticipated situations. Major navigation methods are presented and relevance of traditional human learning theory is discussed. A new navigation technique linking graph theory and incidental learning is introduced.

  15. Understanding satellite navigation

    CERN Document Server

    Acharya, Rajat

    2014-01-01

    This book explains the basic principles of satellite navigation technology with the bare minimum of mathematics and without complex equations. It helps you to conceptualize the underlying theory from first principles, building up your knowledge gradually using practical demonstrations and worked examples. A full range of MATLAB simulations is used to visualize concepts and solve problems, allowing you to see what happens to signals and systems with different configurations. Implementation and applications are discussed, along with some special topics such as Kalman Filter and Ionosphere. W

  16. Navigating Hypermasculine Terrains

    DEFF Research Database (Denmark)

    Henriksen, Ann-Karina Eske

    2015-01-01

    The study addresses how young women navigate urban terrains that are characterized by high levels of interpersonal aggression and crime. It is argued that young women apply a range of gendered tactics to establish safety and social mastery, and that these are framed by the limits and possibilities...... imposed by a street-based hypermasculine script. The analysis rests on an ethnographic study among 25 young Danish women aged 13 to 23 experienced in engaging in street-based physical violence. The study suggests that explorations of female tactics can provide a useful method of analysis for understanding...

  17. China Satellite Navigation Conference

    CERN Document Server

    Liu, Jingnan; Fan, Shiwei; Wang, Feixue

    2016-01-01

    These Proceedings present selected research papers from CSNC2016, held during 18th-20th May in Changsha, China. The theme of CSNC2016 is Smart Sensing, Smart Perception. These papers discuss the technologies and applications of the Global Navigation Satellite System (GNSS), and the latest progress made in the China BeiDou System (BDS) especially. They are divided into 12 topics to match the corresponding sessions in CSNC2016, which broadly covered key topics in GNSS. Readers can learn about the BDS and keep abreast of the latest advances in GNSS techniques and applications.

  18. Integrated Navigation System Design for Micro Planetary Rovers: Comparison of Absolute Heading Estimation Algorithms and Nonlinear Filtering

    Directory of Open Access Journals (Sweden)

    Muhammad Ilyas

    2016-05-01

    Full Text Available This paper provides algorithms to fuse relative and absolute microelectromechanical systems (MEMS navigation sensors, suitable for micro planetary rovers, to provide a more accurate estimation of navigation information, specifically, attitude and position. Planetary rovers have extremely slow speed (~1 cm/s and lack conventional navigation sensors/systems, hence the general methods of terrestrial navigation may not be applicable to these applications. While relative attitude and position can be tracked in a way similar to those for ground robots, absolute navigation information is hard to achieve on a remote celestial body, like Moon or Mars, in contrast to terrestrial applications. In this study, two absolute attitude estimation algorithms were developed and compared for accuracy and robustness. The estimated absolute attitude was fused with the relative attitude sensors in a framework of nonlinear filters. The nonlinear Extended Kalman filter (EKF and Unscented Kalman filter (UKF were compared in pursuit of better accuracy and reliability in this nonlinear estimation problem, using only on-board low cost MEMS sensors. Experimental results confirmed the viability of the proposed algorithms and the sensor suite, for low cost and low weight micro planetary rovers. It is demonstrated that integrating the relative and absolute navigation MEMS sensors reduces the navigation errors to the desired level.

  19. Integrated Navigation System Design for Micro Planetary Rovers: Comparison of Absolute Heading Estimation Algorithms and Nonlinear Filtering.

    Science.gov (United States)

    Ilyas, Muhammad; Hong, Beomjin; Cho, Kuk; Baeg, Seung-Ho; Park, Sangdeok

    2016-01-01

    This paper provides algorithms to fuse relative and absolute microelectromechanical systems (MEMS) navigation sensors, suitable for micro planetary rovers, to provide a more accurate estimation of navigation information, specifically, attitude and position. Planetary rovers have extremely slow speed (~1 cm/s) and lack conventional navigation sensors/systems, hence the general methods of terrestrial navigation may not be applicable to these applications. While relative attitude and position can be tracked in a way similar to those for ground robots, absolute navigation information is hard to achieve on a remote celestial body, like Moon or Mars, in contrast to terrestrial applications. In this study, two absolute attitude estimation algorithms were developed and compared for accuracy and robustness. The estimated absolute attitude was fused with the relative attitude sensors in a framework of nonlinear filters. The nonlinear Extended Kalman filter (EKF) and Unscented Kalman filter (UKF) were compared in pursuit of better accuracy and reliability in this nonlinear estimation problem, using only on-board low cost MEMS sensors. Experimental results confirmed the viability of the proposed algorithms and the sensor suite, for low cost and low weight micro planetary rovers. It is demonstrated that integrating the relative and absolute navigation MEMS sensors reduces the navigation errors to the desired level. PMID:27223293

  20. Integrated Navigation System Design for Micro Planetary Rovers: Comparison of Absolute Heading Estimation Algorithms and Nonlinear Filtering

    Science.gov (United States)

    Ilyas, Muhammad; Hong, Beomjin; Cho, Kuk; Baeg, Seung-Ho; Park, Sangdeok

    2016-01-01

    This paper provides algorithms to fuse relative and absolute microelectromechanical systems (MEMS) navigation sensors, suitable for micro planetary rovers, to provide a more accurate estimation of navigation information, specifically, attitude and position. Planetary rovers have extremely slow speed (~1 cm/s) and lack conventional navigation sensors/systems, hence the general methods of terrestrial navigation may not be applicable to these applications. While relative attitude and position can be tracked in a way similar to those for ground robots, absolute navigation information is hard to achieve on a remote celestial body, like Moon or Mars, in contrast to terrestrial applications. In this study, two absolute attitude estimation algorithms were developed and compared for accuracy and robustness. The estimated absolute attitude was fused with the relative attitude sensors in a framework of nonlinear filters. The nonlinear Extended Kalman filter (EKF) and Unscented Kalman filter (UKF) were compared in pursuit of better accuracy and reliability in this nonlinear estimation problem, using only on-board low cost MEMS sensors. Experimental results confirmed the viability of the proposed algorithms and the sensor suite, for low cost and low weight micro planetary rovers. It is demonstrated that integrating the relative and absolute navigation MEMS sensors reduces the navigation errors to the desired level. PMID:27223293

  1. A linguistic and navigational knowledge approach to text navigation

    OpenAIRE

    Couto, Javier; Minel, Jean-Luc

    2008-01-01

    We present an approach to text navigation conceived as a cognitive process exploiting linguistic information present in texts. We claim that the navigational knowledge in-volved in this process can be modeled in a declarative way with the Sextant language. Since Sextant refers exhaustively to specific linguistic phenomena, we have defined a customized text representation. These dif-ferent components are implemented in the text navigation system NaviTexte. Two ap-plications of NaviTexte are de...

  2. Learning for Autonomous Navigation

    Science.gov (United States)

    Angelova, Anelia; Howard, Andrew; Matthies, Larry; Tang, Benyang; Turmon, Michael; Mjolsness, Eric

    2005-01-01

    Robotic ground vehicles for outdoor applications have achieved some remarkable successes, notably in autonomous highway following (Dickmanns, 1987), planetary exploration (1), and off-road navigation on Earth (1). Nevertheless, major challenges remain to enable reliable, high-speed, autonomous navigation in a wide variety of complex, off-road terrain. 3-D perception of terrain geometry with imaging range sensors is the mainstay of off-road driving systems. However, the stopping distance at high speed exceeds the effective lookahead distance of existing range sensors. Prospects for extending the range of 3-D sensors is strongly limited by sensor physics, eye safety of lasers, and related issues. Range sensor limitations also allow vehicles to enter large cul-de-sacs even at low speed, leading to long detours. Moreover, sensing only terrain geometry fails to reveal mechanical properties of terrain that are critical to assessing its traversability, such as potential for slippage, sinkage, and the degree of compliance of potential obstacles. Rovers in the Mars Exploration Rover (MER) mission have got stuck in sand dunes and experienced significant downhill slippage in the vicinity of large rock hazards. Earth-based off-road robots today have very limited ability to discriminate traversable vegetation from non-traversable vegetation or rough ground. It is impossible today to preprogram a system with knowledge of these properties for all types of terrain and weather conditions that might be encountered.

  3. 33 CFR 207.185 - Taylors Bayou, Tex., Beaumont Navigation District Lock; use, administration, and navigation.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Taylors Bayou, Tex., Beaumont Navigation District Lock; use, administration, and navigation. 207.185 Section 207.185 Navigation and Navigable Waters CORPS OF ENGINEERS, DEPARTMENT OF THE ARMY, DEPARTMENT OF DEFENSE NAVIGATION...

  4. Reflection of Ancient Greek Tradition in the 13th c. Premyslid Celestial Globe Saved in Bernkastel-Kues

    Czech Academy of Sciences Publication Activity Database

    Hadravová, Alena; Hadrava, Petr

    Athens : Institute of Historical Research/National Hellenic Research Foundation, 2012 - (Katsiampoura, G.) ISBN 978-960-9538-13-8. [International Conference of the European Society for the History of Science, Scientific Cosmopolitanism and Local Cultures: Religions, Ideologies, Societies /5./. 01.11.2012-03.11.2012, Atény] R&D Projects: GA ČR(CZ) GAP405/11/0034 Institutional support: RVO:68378114 ; RVO:67985815 Keywords : ancient Greek astronomical tradition * celestial globes * Ptolemaic constellations Subject RIV: AB - History; BN - Astronomy, Celestial Mechanics, Astrophysics (ASU-R)

  5. Introductory Course on Satellite Navigation

    Science.gov (United States)

    Giger, Kaspar; Knogl, J. Sebastian

    2012-01-01

    Satellite navigation is widely used for personal navigation and more and more in precise and safety-critical applications. Thus, the subject is suited for attracting the interest of young people in science and engineering. The practical applications allow catching the students' attention for the theoretical background. Educational material on the…

  6. Autonomous Spacecraft Navigation With Pulsars

    CERN Document Server

    Becker, Werner; Jessner, Axel

    2013-01-01

    An external reference system suitable for deep space navigation can be defined by fast spinning and strongly magnetized neutron stars, called pulsars. Their beamed periodic signals have timing stabilities comparable to atomic clocks and provide characteristic temporal signatures that can be used as natural navigation beacons, quite similar to the use of GPS satellites for navigation on Earth. By comparing pulse arrival times measured on-board a spacecraft with predicted pulse arrivals at a reference location, the spacecraft position can be determined autonomously and with high accuracy everywhere in the solar system and beyond. The unique properties of pulsars make clear already today that such a navigation system will have its application in future astronautics. In this paper we describe the basic principle of spacecraft navigation using pulsars and report on the current development status of this novel technology.

  7. Densification of the International Celestial Reference Frame: Results of EVN Observations

    CERN Document Server

    Charlot, P; Jacobs, C S; Ma, C; Sovers, O J; Baudry, A

    2004-01-01

    The current realization of the International Celestial Reference Frame (ICRF) comprises a total of 717 extragalactic radio sources distributed over the entire sky. An observing program has been developed to densify the ICRF in the northern sky using the European VLBI network (EVN) and other radio telescopes in Spitsbergen, Canada and USA. Altogether, 150 new sources selected from the Jodrell Bank-VLA Astrometric Survey were observed during three such EVN+ experiments conducted in 2000, 2002 and 2003. The sources were selected on the basis of their sky location in order to fill the "empty" regions of the frame. A secondary criterion was based on source compactness to limit structural effects in the astrometric measurements. All 150 new sources have been successfully detected and the precision of the estimated coordinates in right ascension and declination is better than 1 milliarcsecond (mas) for most of them. A comparison with the astrometric positions from the Very Long baseline Array Calibrator Survey for 1...

  8. Signature of the celestial spheres discovering order in the solar system

    CERN Document Server

    Warm, Harmut

    2010-01-01

    "A milestone in modern research on the the harmony of the spheres." - Novalis magazine "This book reignites the debate on the harmony of the spheres." - Das Goetheanum Is the solar system ordered, or is it simply the result of random and chaotic accidents? This book takes us on a powerful and compelling journey of discovery, revealing the celestial spheres' astonishingly complex patterns. The movements of the planets are found to correspond accurately with simple geometric figures and musical intervals, pointing to an exciting new perspective on the ancient idea of a "harmony of the spheres". Hartmut Warm's detailed presentation incorporates the distances, velocities and periods of conjunction of the planets, as well as the rotations of the Sun, Moon and Venus. Numerous graphics - including colour plates - illustrate the extraordinary beauty of the geometrical forms that result when the movements of several planets are viewed in relation to one another. In addition, the author describes and analyses the conce...

  9. On the impact of correlation information on the orientation parameters between celestial reference frame realizations

    CERN Document Server

    Sokolova, Yulia

    2014-01-01

    In this study, we compared results of determination of the orientation angles between celestial reference frames realized by radio source position catalogues using three methods of accounting for correlation information: using the position errors only, using additionally the correlations be-tween the right ascension and declination (RA/DE correlations) reported in radio source position catalogues published in the IERS format, and using the full covariance matrix. The computations were performed with nine catalogues computed at eight analysis centres. Our analysis has shown that using the RA/DE correlations only slightly influences the computed rotational angles, whereas using the full correlation matrices leads to substantial change in the orientation parameters be-tween the compared catalogues.

  10. The Lens-Thirring effect in the anomalistic period of celestial bodies

    CERN Document Server

    Haranas, Ioannis; Gkigkitzis, Ioannis

    2013-01-01

    In the weak field and slow motion approximation, the general relativistic field equations are linearized, resembling those of the electromagnetic theory. In a way analogous to that of a moving charge generating a magnetic field, a mass energy current can produce a gravitomagnetic field. In this contribution, the motion of a secondary celestial body is studied under the influence of the gravitomagnetic force generated by a spherical primary. More specifically, two equations are derived to approximate the periastron time rate of change and its total variation over one revolution (i.e., the difference between the anomalistic period and the Keplerian period). Kinematically, this influence results to an apsidal motion. The aforementioned quantities are numerically estimated for Mercury, the companion star of the pulsar PSR 1913 plus 16, the companion planet of the star HD 80606 and the artificial Earth satellite GRACE A. The case of the artificial Earth satellite GRACE A is also considered, but the results present...

  11. On the implications of the Galactic aberration in proper motions for celestial reference frame

    CERN Document Server

    Malkin, Zinovy

    2014-01-01

    During the last years, much attention has been paid to the astrometric implications of the galactic aberration in proper motions (GA). This effect causes systematic errors in astrometric measurements at a microarcsecond level. Some authors consider it so serious that it requires redefinition of the celestial reference system (CRF). We argue that such attention to the GA is too much exaggerated. It is just a small astrometric correction that must be taken into account during highly accurate astrometric and geodetic data processing. The accuracy of this correction depends on accuracy of the Galactic rotation parameters and, for most application, on the accuracy of the rotation matrix between Galactic and equatorial systems. Our analysis has shown that our today knowledge of these two factors is sufficient to compute the GA correction with accuracy of better than 10%. The remaining effect at a level of few tenths microarcsecond/yr is negligible nowadays. Another consequence of introducing the GA correction is ne...

  12. New developments for modern celestial mechanics. I. General coplanar three-body systems. Application to exoplanets

    CERN Document Server

    Mardling, Rosemary A

    2013-01-01

    Modern applications of celestial mechanics include the study of closely packed systems of exoplanets, circumbinary planetary systems, binary-binary interactions in star clusters, and the dynamics of stars near the galactic centre. While developments have historically been guided by the architecture of the Solar System, the need for more general formulations with as few restrictions on the parameters as possible is obvious. Here we present clear and concise generalisations of two classic expansions of the three-body disturbing function, simplifying considerably their original form and making them accessible to the non-specialist. Governing the interaction between the inner and outer orbits of a hierarchical triple, the disturbing function in its general form is the conduit for energy and angular momentum exchange and as such, governs the secular and resonant evolution of the system and its stability characteristics. Focusing here on coplanar systems, the first expansion is one in the ratio of inner to outer se...

  13. Feasibility study of scanning celestial Attitude System (SCADS) for Earth Resources Technology Satellite (ERTS)

    Science.gov (United States)

    1971-01-01

    The feasibility of using the Scanning Celestial Attitude Determination System (SCADS) during Earth Resources Technology Satellite (ERTS) missions to compute an accurate spacecraft attitude by use of stellar measurements is considered. The spacecraft is local-vertical-stabilized. A heuristic discussion of the SCADS concept is first given. Two concepts are introduced: a passive system which contains no moving parts, and an active system in which the reticle is caused to rotate about the sensor's axis. A quite complete development of the equations of attitude motions is then given. These equations are used to generate the true attitude which in turn is used to compute the transit times of detectable stars and to determine the errors associated with the SCADS attitude. A more complete discussion of the analytical foundation of SCADS concept and its use for the geometries particular to this study, as well as salient design parameters for the passive and active systems are included.

  14. El origen de los rangos de la jerarquía celestial

    OpenAIRE

    Almirall Arnal, Juan

    2013-01-01

    [spa]"El origen de los rangos de la jerarquía celestial" es un estudio sobre las clasificaciones y ordenaciones de los rangos del intelecto divino inspiradas en el diálogo “Parménides” de Platón. Por tanto, no se trata de una obra teológica, sino de la influencia de la dialéctica de dicho diálogo en la teología, primero pagana y después cristiana. El presente estudio se enmarcaría en la disciplina denominada noética, que estudia los desarrollos del concepto de intelecto o “noûs” en la filosof...

  15. SAS-2 observations of celestial diffuse gamma radiation above 30 MeV

    Science.gov (United States)

    Thompson, D. J.; Fichtel, C. E.; Kniffen, D. A.; Hartman, R. C.

    1974-01-01

    The small astronomy satellite, SAS-2, used a 32-deck magnetic core digitized spark chamber to study gamma rays with energies above 30 MeV. Data for four regions of the sky away from the galactic plane were analyzed. These regions show a finite, diffuse flux of gamma rays with a steep energy spectrum, and the flux is uniform over all the regions. Represented by a power law, the differential energy spectrum shows an index of 2.5 + or - 0.4. The steep SAS-2 spectrum and the lower energy data are reasonably consistent with a neutral pion gamma-ray spectrum which was red-shifted (such as that proposed by some cosmological theories). It is concluded that the diffuse celestial gamma ray spectrum observed presents the possibility of cosmological studies and possible evidence for a residual cosmic ray density, and supports the galactic superclusters of matter and antimatter remaining from baryon-symmetric big bang.

  16. Observation of celestial high energy gamma rays from SAS-II

    Science.gov (United States)

    Fichtel, C. E.; Hartman, R. C.; Kniffen, D. A.

    1974-01-01

    The Small Astronomy Satellite (SAS)-II, launched on Nov. 15, 1973, carried into orbit a 32-deck magnetic-core digitized-spark-chamber gamma-ray telescope to study celestial gamma radiation in the energy range above 30 MeV. As of May 21, 1973, SAS-II had viewed approximately half the sky, including the galactic center region, the galactic anti-center, and several regions off the galactic plane, and about one-third of the data from eight weeks of viewing has been analyzed. A finite diffuse flux for regions with galactic latitudes greater than 20 deg has been detected with a very steep energy spectrum. Combining this result with low-energy gamma-ray data yields a picture suggesting a cosmological origin for this radiation.

  17. GRAIL gravity field determination using the Celestial Mechanics Approach - status report

    Science.gov (United States)

    Bertone, S.; Arnold, D.; Jäggi, A.; Beutler, G.; Mervart, L.

    2015-10-01

    The NASA mission GRAIL (Gravity Recovery And Interior Laboratory [1]) inherits its concept from the GRACE (Gravity Recovery And Climate Experiment)mission to determine the gravity field of the Moon. The use of inter-satellite Ka-band range-rate (KBRR) observations enables data aquisition even when the spacecraft are not tracked from the Earth [2]. The data allows for a highly accurate estimation of the lunar gravity field on both sides of the Moon, which is crucial to improve the understanding of its internal structure and thermal evolution. In this presentation we dis- cuss our latest GRAIL-based lunar gravity fields generated with the Celestial Mechanics Approach using the Bernese Software.

  18. International Celestial Reference Frame (ICRF): mantenimiento y extensión

    Science.gov (United States)

    Ma, C.; Arias, E. F.; Eubanks, T.; Fey, A. L.; Gontier, A.-M.; Jacobs, C. S.; Sovers, O. J.; Archinal, B. A.; Charlot, P.

    A partir de enero de 1998 el sistema de referencia celeste convencional está representado por el International Celestial Reference System (ICRS) y materializado a través de las coordenadas VLBI del conjunto de radiofuentes extragalácticas que conforman el International Celestial Reference Frame (ICRF). La primera realización del ICRF, fue elaborada en 1995 por un grupo de expertos designado por la IAU, la que encomendó al International Earth Rotation Service el mantenimiento del ICRS, del ICRF y del vínculo con marcos de referencia en otras frecuencias. Una primera extensión del ICRF se realizó entre abril y junio de 1999, con el objetivo primario de proveer posiciones de radiofuentes extragalácticas observadas a partir de julio de 1995 y de mejorar las posiciones de las fuentes ``candidatas" con la inclusión de observaciones adicionales. Objetivos secundarios fueron monitorear a las radiofuentes para verificar que siguen siendo adecuadas para realizar al ICRF y mejorar las técnicas de análisis de datos. Como resultado del nuevo análisis se obtuvo una solución a partir de la cual se construyó la primera extensión del ICRF, denominada ICRF - Ext.1. Ella representa al ICRS, sus fuentes de definición se mantienen con las mismas posiciones y errores que en la primera realización del ICRF; las demás radiofuentes tienen coordenadas mejor determinadas que en ICRF; el marco de referencia se densificó con el agregado de 59 nuevas radiofuentes.

  19. Interaction between celestial and terrestrial reference frames and some considerations for the next VLBI-based ICRF

    CERN Document Server

    Malkin, Zinovy; Ma, Chopo; Lambert, Sebastien

    2014-01-01

    In this paper we outline several problems related to the realization of the international celestial and terrestrial reference frames ICRF and ITRF at the millimeter level of accuracy, with emphasis on ICRF issues. The main topics considered are: analysis of the current status of the ICRF, mutual impact of ICRF and ITRF, and some considerations for future ICRF realizations.

  20. Lunar Navigation Architecture Design Considerations

    Science.gov (United States)

    D'Souza, Christopher; Getchius, Joel; Holt, Greg; Moreau, Michael

    2009-01-01

    The NASA Constellation Program is aiming to establish a long-term presence on the lunar surface. The Constellation elements (Orion, Altair, Earth Departure Stage, and Ares launch vehicles) will require a lunar navigation architecture for navigation state updates during lunar-class missions. Orion in particular has baselined earth-based ground direct tracking as the primary source for much of its absolute navigation needs. However, due to the uncertainty in the lunar navigation architecture, the Orion program has had to make certain assumptions on the capabilities of such architectures in order to adequately scale the vehicle design trade space. The following paper outlines lunar navigation requirements, the Orion program assumptions, and the impacts of these assumptions to the lunar navigation architecture design. The selection of potential sites was based upon geometric baselines, logistical feasibility, redundancy, and abort support capability. Simulated navigation covariances mapped to entry interface flightpath- angle uncertainties were used to evaluate knowledge errors. A minimum ground station architecture was identified consisting of Goldstone, Madrid, Canberra, Santiago, Hartebeeshoek, Dongora, Hawaii, Guam, and Ascension Island (or the geometric equivalent).

  1. Navigable networks as Nash equilibria of navigation games

    Science.gov (United States)

    Gulyás, András; Bíró, József J.; Kőrösi, Attila; Rétvári, Gábor; Krioukov, Dmitri

    2015-07-01

    Common sense suggests that networks are not random mazes of purposeless connections, but that these connections are organized so that networks can perform their functions well. One function common to many networks is targeted transport or navigation. Here, using game theory, we show that minimalistic networks designed to maximize the navigation efficiency at minimal cost share basic structural properties with real networks. These idealistic networks are Nash equilibria of a network construction game whose purpose is to find an optimal trade-off between the network cost and navigability. We show that these skeletons are present in the Internet, metabolic, English word, US airport, Hungarian road networks, and in a structural network of the human brain. The knowledge of these skeletons allows one to identify the minimal number of edges, by altering which one can efficiently improve or paralyse navigation in the network.

  2. A greedy-navigator approach to navigable city plans

    CERN Document Server

    Lee, Sang Hoon

    2012-01-01

    We use a set of four theoretical navigability indices for street maps to investigate the shape of the resulting street networks, if they are grown by optimizing these indices. The indices compare the performance of simulated navigators (having a partial information about the surroundings, like humans in many real situations) to the performance of optimally navigating individuals. We show that our simple greedy shortcut construction strategy generates the emerging structures that are different from real road network, but not inconceivable. The resulting city plans, for all navigation indices, share common qualitative properties such as the tendency for triangular blocks to appear, while the more quantitative features, such as degree distributions and clustering, are characteristically different depending on the type of metrics and routing strategies. We show that it is the type of metrics used which determines the overall shapes characterized by structural heterogeneity, but the routing schemes contribute to m...

  3. Navigation/Prop Software Suite

    Science.gov (United States)

    Bruchmiller, Tomas; Tran, Sanh; Lee, Mathew; Bucker, Scott; Bupane, Catherine; Bennett, Charles; Cantu, Sergio; Kwong, Ping; Propst, Carolyn

    2012-01-01

    Navigation (Nav)/Prop software is used to support shuttle mission analysis, production, and some operations tasks. The Nav/Prop suite containing configuration items (CIs) resides on IPS/Linux workstations. It features lifecycle documents, and data files used for shuttle navigation and propellant analysis for all flight segments. This suite also includes trajectory server, archive server, and RAT software residing on MCC/Linux workstations. Navigation/Prop represents tool versions established during or after IPS Equipment Rehost-3 or after the MCC Rehost.

  4. Discovery of Individual User Navigation Styles

    OpenAIRE

    Herder, E.; Juvina, I.

    2004-01-01

    Individual differences have been shown to lead to different navigation styles. In this paper we present a pilot study that aims at finding predictors for users’ vulnerability to experience disorientation that can be gathered unobtrusively and in real-time. We identified two navigation styles that we called flimsy navigation and laborious navigation that together predict users’ perceived disorientation. Our findings suggest that adaptive navigation support that addresses these navigation style...

  5. Navigating "Assisted Dying".

    Science.gov (United States)

    Schipper, Harvey

    2016-02-01

    Carter is a bellwether decision, an adjudication on a narrow point of law whose implications are vast across society, and whose impact may not be realized for years. Coupled with Quebec's Act Respecting End-of-life Care it has sharply changed the legal landscape with respect to actively ending a person's life. "Medically assisted dying" will be permitted under circumstances, and through processes, which have yet to be operationally defined. This decision carries with it moral assumptions, which mean that it will be difficult to reach a unifying consensus. For some, the decision and Act reflect a modern acknowledgement of individual autonomy. For others, allowing such acts is morally unspeakable. Having opened the Pandora's Box, the question becomes one of navigating a tolerable societal path. I believe it is possible to achieve a workable solution based on the core principle that "medically assisted dying" should be a very rarely employed last option, subject to transparent ongoing review, specifically as to why it was deemed necessary. My analysis is based on 1. The societal conditions in which have fostered demand for "assisted dying", 2. Actions in other jurisdictions, 3. Carter and Quebec Bill 52, 4. Political considerations, 5. Current medical practice. Leading to a series of recommendations regarding. 1. Legislation and regulation, 2. The role of professional regulatory agencies, 3. Medical professions education and practice, 4. Public education, 5. Health care delivery and palliative care. Given the burden of public opinion, and the legal steps already taken, a process for assisted-dying is required. However, those legal and regulatory steps should only be considered a necessary and defensive first step in a two stage process. The larger goal, the second step, is to drive the improvement of care, and thus minimize assisted-dying. PMID:27169205

  6. Navigation System of Marks Areas - USACE IENC

    Data.gov (United States)

    Department of Homeland Security — These inland electronic Navigational charts (IENCs) were developed from available data used in maintenance of Navigation channels. Users of these IENCs should be...

  7. Radio Navigation Waveform Experiment Project

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA is installing the Communications, Navigation, and Networking reConfigurable Testbed (CoNNeCT) onto the truss of the International Space Station to demonstrate...

  8. NOAA Electronic Navigational Charts (ENC)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Office of Coast Survey (OCS) has been involved in the development of a NOAA Electronic Navigational Chart (NOAA ENC) suite to support the marine transportation...

  9. FLASH LIDAR Based Relative Navigation

    Science.gov (United States)

    Brazzel, Jack; Clark, Fred; Milenkovic, Zoran

    2014-01-01

    Relative navigation remains the most challenging part of spacecraft rendezvous and docking. In recent years, flash LIDARs, have been increasingly selected as the go-to sensors for proximity operations and docking. Flash LIDARS are generally lighter and require less power that scanning Lidars. Flash LIDARs do not have moving parts, and they are capable of tracking multiple targets as well as generating a 3D map of a given target. However, there are some significant drawbacks of Flash Lidars that must be resolved if their use is to be of long-term significance. Overcoming the challenges of Flash LIDARs for navigation-namely, low technology readiness level, lack of historical performance data, target identification, existence of false positives, and performance of vision processing algorithms as intermediaries between the raw sensor data and the Kalman filter-requires a world-class testing facility, such as the Lockheed Martin Space Operations Simulation Center (SOSC). Ground-based testing is a critical step for maturing the next-generation flash LIDAR-based spacecraft relative navigation. This paper will focus on the tests of an integrated relative navigation system conducted at the SOSC in January 2014. The intent of the tests was to characterize and then improve the performance of relative navigation, while addressing many of the flash LIDAR challenges mentioned above. A section on navigation performance and future recommendation completes the discussion.

  10. SEVEN-YEAR WILKINSON MICROWAVE ANISOTROPY PROBE (WMAP ) OBSERVATIONS: PLANETS AND CELESTIAL CALIBRATION SOURCES

    International Nuclear Information System (INIS)

    We present WMAP seven-year observations of bright sources which are often used as calibrators at microwave frequencies. Ten objects are studied in five frequency bands (23-94 GHz): the outer planets (Mars, Jupiter, Saturn, Uranus, and Neptune) and five fixed celestial sources (Cas A, Tau A, Cyg A, 3C274, and 3C58). The seven-year analysis of Jupiter provides temperatures which are within 1σ of the previously published WMAP five-year values, with slightly tighter constraints on variability with orbital phase (0.2% ± 0.4%), and limits (but no detections) on linear polarization. Observed temperatures for both Mars and Saturn vary significantly with viewing geometry. Scaling factors are provided which, when multiplied by the Wright Mars thermal model predictions at 350 μm, reproduce WMAP seasonally averaged observations of Mars within ∼2%. An empirical model is described which fits brightness variations of Saturn due to geometrical effects and can be used to predict the WMAP observations to within 3%. Seven-year mean temperatures for Uranus and Neptune are also tabulated. Uncertainties in Uranus temperatures are 3%-4% in the 41, 61, and 94 GHz bands; the smallest uncertainty for Neptune is 8% for the 94 GHz band. Intriguingly, the spectrum of Uranus appears to show a dip at ∼30 GHz of unidentified origin, although the feature is not of high statistical significance. Flux densities for the five selected fixed celestial sources are derived from the seven-year WMAP sky maps and are tabulated for Stokes I, Q, and U, along with polarization fraction and position angle. Fractional uncertainties for the Stokes I fluxes are typically 1% to 3%. Source variability over the seven-year baseline is also estimated. Significant secular decrease is seen for Cas A and Tau A: our results are consistent with a frequency-independent decrease of about 0.53% per year for Cas A and 0.22% per year for Tau A. We present WMAP polarization data with uncertainties of a few percent for Tau

  11. Research on CNS/SINS Integrated Navigation by Simulation%基于星敏感器的天文/惯导组合导航仿真研究

    Institute of Scientific and Technical Information of China (English)

    罗宁; 周磊; 张锐; 樊建文

    2014-01-01

    本文通过仿真实验,研究了基于星敏感器的天文/惯导组合导航系统的导航性能和特点。首先分析了天文导航的基本原理,并给出了天文/惯导组合导航算法的理论模型。在此基础上,建立了天文导航和捷联惯性导航的仿真模型,实现了天文/惯导组合导航系统仿真。仿真结果表明:基于星敏感器的天文/惯导组合导航能够有效抑制惯导的长时漂移累积误差,有利于实现机载远程长航时的高精度导航。%According to the simulation experiments, the performance and characteristic of CNS/INS integrated navigation are analyzed in this paper. Firstly, the basic theory of celestial navigation is discussed, and the algorithm of CNS/INS integrated navigation is presented. Then, the celestial navigation and inertial navigation simulation models are set up. What’s more, the CNS/INS integrated navigation simulation system is realized. The simulation results show that the accumulative errors of inertial navigation are checked effectively by the CNS/INS integrated navigation, which is benefit to realize the high precision airborne navigation with long-distance and long-endurance.

  12. Periodic, Quasi-Periodic and Chaotic Motions in Celestial Mechanics: Theory and Applications Selected papers from the Fourth Meeting on Celestial Mechanics, CELMEC IV San Martino al Cimino (Italy), 11–16 September 2005

    CERN Document Server

    Celletti, A

    2006-01-01

    The book provides the most recent advances of Celestial Mechanics, as provided by high-level scientists working in this field. It covers theoretical investigations as well as applications to concrete problems. Outstanding review papers are included in the book and they introduce the reader to leading subjects, like the variational approaches to find periodic orbits, the stability theory of the N-body problem, the spin-orbit resonances and chaotic dynamics, the space debris polluting the circumterrestrial space.

  13. ASTEP South: An Antarctic Search for Transiting Planets around the celestial South pole

    CERN Document Server

    Crouzet, Nicolas; Blazit, Alain; Bonhomme, Serge; Fanteï-Caujolle, Yan; Fressin, François; Guillot, Tristan; Schmider, François-Xavier; Valbousquet, Franck; Bondoux, Erick; Challita, Zalpha; Abe, Lyu; Daban, Jean-Baptiste; Gouvret, Carole

    2008-01-01

    ASTEP South is the first phase of the ASTEP project that aims to determine the quality of Dome C as a site for future photometric searches for transiting exoplanets and discover extrasolar planets from the Concordia base in Antarctica. ASTEP South consists of a front-illuminated 4k x 4k CCD camera, a 10 cm refractor, and a simple mount in a thermalized enclosure. A double-glass window is used to reduce temperature variations and its accompanying turbulence on the optical path. The telescope is fixed and observes a 4 x 4 square degrees field of view centered on the celestial South pole. With this design, A STEP South is very stable and observes with low and constant airmass, both being important issues for photometric precision. We present the project, we show that enough stars are present in our field of view to allow the detection of one to a few transiting giant planets, and that the photometric precision of the instrument should be a few mmag for stars brighter than magnitude 12 and better than 10 mmag for...

  14. Astropol: Russian pilot project on coordinated observations of hazardous celestial objects

    Science.gov (United States)

    Ibrahimov, Mansur

    Cooperative graund-based ASTROPOL (ASTeRoid and cOmet POLice) project had been started in June 2012. ASTROPOL was initiated and currently advised by the Institute of Astronomy RAS (INASAN). It is believed to be a long-term dedicated Russian pilot project on coordinated observations of hazardous celestial objects - potentially hazardous asteroids, comets, and meteoroids. Basic facility of ASTROPOL is its (permanently enlarged) observational network which presently incorporates 12 academical and university observatories. Network includes all the largest Russian optical telescopes (SAO RAS 6m, INASAN TB 2m, ISTP SSO 1.6m) and a number of 1-1.5m telescopes located around Russia (Uzbek UBAI MAO 1.5m, Russian-Turkish 1.5m RTT150 in Antalya, Turkey, Latvian IAUL BAO 1.2m Schmidt, and Ukrainian CrAO Simeiz 1m). All mentioned telescopes together with a number of 0.4-0.6m ones have been using to get low-resolution spectroscopy, photometry, and astrometry of hazardous objects. By the end of 2013 two successful coordinated sessions had been undertaken by ASTROPOL cooperation: observations of Apophis in Jan13-Feb28 and 2010 CF19 in Aug16-Sep02 2013. Observation and reduction methods and results obtained during the both coordinated sessions as well as some current problem and prospects of the ASTROPOL cooperation are analysed and discussed in the talk.

  15. Quantum Celestial Mechanics: Large-scale Gravitational Quantization States in Galaxies and the Universe

    Science.gov (United States)

    Preston, Howard G.; Potter, Franklin

    2006-03-01

    We report a new theory of celestial mechanics for gravitationally bound systems based upon a gravitational wave equation derived from the general relativistic Hamilton-Jacobi equation. The single ad hoc assumption is that the large-scale physical properties depend only on the ratio of the bound system's total angular momentum to its total mass. The theory predicts quantization states for the Solar System and for galaxies. The galactic quantization determines the energy and angular momentum eigenstates without requiring dark matter, and predicts expressions for the galactic disk rotation velocity, the baryonic Tully-Fisher relation, the MOND acceleration parameter, the large-angle gravitational lensing, and the shape, stability and number of arms in spiral galaxies. Applied to the universe, the theory has a repulsive effective gravitational potential that predicts a new Hubble relation and explains the observed apparent acceleration of distant supernovae with the matter/energy density of the universe at the critical density with only about 5% matter content. We suggest a laboratory experiment with a torsion bar near a rotating mass. This theory is not quantum gravity.

  16. The norm of the position shift of a celestial body upon variation of its orbit

    Science.gov (United States)

    Batmunkh, N.; Sannikova, T. N.; Kholshevnikov, K. V.; Shaidulin, V. Sh.

    2016-03-01

    A precise estimate of the variation of the position of a celestial body in the case of small variations of the elements of its orbit is obtained using an Euclidean (mean-square) norm for the deviation in the position. A relatively simple expression for the mean-square deviation of the radius vector d r in terms of the deviations of the elements is derived. These are taken to be first-order small quantitites, with second-order quantities neglected. This relation is applied to estimate the norm || d r|| in two problems. In the first one, small and constant differences between six orbital elements (including the mean anomaly) are considered for two orbits. In the second one, a zero-mass point moves under the gravitation of a central body and a small perturbing acceleration F. The vector F is taken to be constant in a co-moving coordinate system with axes directed along the radius vector, the transversal, and the binormal vector. In this latter problem, d r is the difference between the position vectors in the osculating and mean orbit. The norm || d r||2 is the weighted sum of the squares of the components of F, neglecting higher-order small quantities. The coefficients of the quadratic form depend only on the semi-major axis and the eccentricity of the mean orbit. The results are applied to the motion of a small asteroid under the action of a low-thrust engine imparting a small force.

  17. The effects of frequency-dependent quasar evolution on the celestial reference frame

    CERN Document Server

    Shabala, Stanislav; McCallum, Jamie; Titov, Oleg; Blanchard, Jay; Lovell, Jim; Watson, Christopher

    2013-01-01

    We examine the relationship between source position stability and astrophysical properties of radio-loud quasars making up the International Celestial Reference Frame. We construct light curves for 95 most frequently observed ICRF2 quasars at both the geodetic VLBI observing bands. Because the appearance of new quasar components corresponds to an increase in quasar flux density, these light curves allow us to probe source structure on sub-100 microarcsecond scales, much smaller than conventional VLBI imaging. Flux density monitoring also allows us to trace the evolution of quasar structure. We test how source position stability depends on three astrophysical parameters: (1) Flux density variability at X-band; (2) Time lag between S and X-band light curves; (3) Spectral index rms, defined as the variability in the ratio between S and X-band flux densities. We find that small (<0.15 years) time lags between S and X-band light curves and low (<0.10) spectral index variability are excellent indicators of po...

  18. Initial deep LOFAR observations of Epoch of Reionization windows: I. The North Celestial Pole

    CERN Document Server

    Yatawatta, S; Brentjens, M A; Labropoulos, P; Pandey, V N; Kazemi, S; Zaroubi, S; Koopmans, L V E; Offringa, A R; Jelic, V; Rubi, O Martinez; Veligatla, V; Wijnholds, S J; Brouw, W N; Bernardi, G; Ciardi, B; Daiboo, S; Harker, G; Mellema, G; Schaye, J; Thomas, R; Vedantham, H; Chapman, E; Abdalla, F B; Alexov, A; Anderson, J; Avruch, I M; Batejat, F; Bell, M E; Bell, M R; Bentum, M; Best, P; Bonafede, A; Bregman, J; Breitling, F; van de Brink, R H; Broderick, J W; Bruggen, M; Conway, J; de Gasperin, F; de Geus, E; Duscha, S; Falcke, H; Fallows, R A; Ferrari, C; Frieswijk, W; Garrett, M A; Griessmeier, J M; Gunst, A W; Hassall, T E; Hessels, J W T; Hoeft, M; Iacobelli, M; Juette, E; Karastergiou, A; Kondratiev, V I; Kramer, M; Kuniyoshi, M; Kuper, G; van Leeuwen, J; Maat, P; Mann, G; McKean, J P; Mevius, M; Mol, J D; Munk, H; Nijboer, R; Noordam, J E; Norden, M J; Orru, E; Paas, H; Pandey-Pommier, M; Pizzo, R; Polatidis, A G; Reich, W; Rottgering, H J A; Sluman, J; Smirnov, O; Stappers, B; Tagger, M; Tang, Y; Tasse, C; ter Veen, S; Vermeulen, R; van Weeren, R J; Wise, M; Wucknitz, O; Zarka, P

    2013-01-01

    The aim of the LOFAR Epoch of Reionization (EoR) project is to detect the spectral fluctuations of the redshifted HI 21cm signal. This signal is weaker by several orders of magnitude than the astrophysical foreground signals and hence, in order to achieve this, very long integrations, accurate calibration for stations and ionosphere and reliable foreground removal are essential. One of the prospective observing windows for the LOFAR EoR project will be centered at the North Celestial Pole (NCP). We present results from observations of the NCP window using the LOFAR highband antenna (HBA) array in the frequency range 115 MHz to 163 MHz. The data were obtained in April 2011 during the commissioning phase of LOFAR. We used baselines up to about 30 km. With about 3 nights, of 6 hours each, effective integration we have achieved a noise level of about 100 microJy/PSF in the NCP window. Close to the NCP, the noise level increases to about 180 microJy/PSF, mainly due to additional contamination from unsubtracted nea...

  19. Optical identifications of celestial high energy sources with the Telescopio Nazionale Galileo

    International Nuclear Information System (INIS)

    To ascertain the nature of celestial high energy sources, it is crucial to identify their optical counterparts. However, the currently available astronomical public optical databases do not provide an adequate support for a systematic high energy sources identification work. In particular, the optical limiting magnitude represents a severe limitation since the deepest flux limits reached by X-ray surveys require of course similarly deeper optical catalogs to homogeneously sample the available parameter space. Nonetheless, dedicated spectroscopic campaigns are being carried out successfully with the Telescopio Nazionale Galileo (TNG), a 4-m class telescope. To set up a winning observational campaign, the first and most important step is to define a strong science case, as it will allow for selections of good targets for observations: the key is to increase the identification efficiency while keeping down the required telescope time. In this context, as the Principal Investigator, I will give an overview of the first spectroscopic campaign carried out at the TNG to identify Swift X-ray serendipitous sources, and I will show the valuable results achieved with only one night of observations. As a second example, I will review the strategy for the northern-sky classification of candidate blazars associated to unidentified Fermi γ-ray sources, and I will show the results coming from the related observational campaign at TNG I have been involved during the last two years.

  20. A Two-Colour CCD Survey of the North Celestial Cap: I. The Method

    CERN Document Server

    Gorbikov, Evgeny; Afonso, Cristina

    2009-01-01

    We describe technical aspects of an astrometric and photometric survey of the North Celestial Cap (NCC), from the Pole (DEC=90 deg) to DEC=80 deg, in support of the TAUVEX mission. This region, at galactic latitudes from ~ 17 deg to ~ 37 deg, has poor coverage in modern CCD-based surveys. The observations are performed with the Wise Observatory one-meter reflector and with a new mosaic CCD camera (LAIWO) that images in the Johnson-Cousins R and I bands a one-square-degree field with subarcsec pixels. The images are treated using IRAF and SExtractor to produce a final catalogue of sources. The astrometry, based on the USNO-A2.0 catalogue, is good to ~ 1 arcsec and the photometry is good to ~ 0.1 mag for point sources brighter than R=20.0 or I=19.1 mag. The limiting magnitudes of the survey, defined at photometric errors smaller than 0.15 mag, are 20.6 mag (R) and 19.6 (I). We separate stars from non-stellar objects based on the object shapes in the R and I bands, attempting to reproduce the SDSS star/galaxy di...

  1. Seven-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Planets and Celestial Calibration Sources

    CERN Document Server

    Weiland, J L; Hill, R S; Wollack, E; Hinshaw, G; Greason, M R; Jarosik, N; Page, L; Bennett, C L; Dunkley, J; Gold, B; Halpern, M; Kogut, A; Komatsu, E; Larson, D; Limon, M; Meyer, S S; Nolta, M R; Smith, K M; Spergel, D N; Tucker, G S; Wright, E L

    2010-01-01

    We present WMAP seven-year observations of bright sources which are often used as calibrators at microwave frequencies. Ten objects are studied in five frequency bands (23 - 94 GHz): the outer planets (Mars, Jupiter, Saturn, Uranus and Neptune) and five fixed celestial sources (Cas A, Tau A, Cyg A, 3C274 and 3C58). The seven-year analysis of Jupiter provides temperatures which are within 1-sigma of the previously published WMAP five-year values, with slightly tighter constraints on variability with orbital phase, and limits (but no detections) on linear polarization. Scaling factors are provided which, when multiplied by the Wright Mars thermal model predictions at 350 micron, reproduce WMAP seasonally averaged observations of Mars within ~2%. An empirical model is described which fits brightness variations of Saturn due to geometrical effects and can be used to predict the WMAP observations to within 3%. Seven-year mean temperatures for Uranus and Neptune are also tabulated. Uncertainties in Uranus temperatu...

  2. 33 CFR 66.10-15 - Aids to navigation.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Aids to navigation. 66.10-15 Section 66.10-15 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY AIDS TO NAVIGATION PRIVATE AIDS TO NAVIGATION Uniform State Waterway Marking System § 66.10-15 Aids to navigation....

  3. Modelling group navigation: transitive social structures improve navigational performance.

    Science.gov (United States)

    Flack, Andrea; Biro, Dora; Guilford, Tim; Freeman, Robin

    2015-07-01

    Collective navigation demands that group members reach consensus on which path to follow, a task that might become more challenging when the group's members have different social connections. Group decision-making mechanisms have been studied successfully in the past using individual-based modelling, although many of these studies have neglected the role of social connections between the group's interacting members. Nevertheless, empirical studies have demonstrated that individual recognition, previous shared experiences and inter-individual familiarity can influence the cohesion and the dynamics of the group as well as the relative spatial positions of specific individuals within it. Here, we use models of collective motion to study the impact of social relationships on group navigation by introducing social network structures into a model of collective motion. Our results show that groups consisting of equally informed individuals achieve the highest level of accuracy when they are hierarchically organized with the minimum number of preferred connections per individual. We also observe that the navigational accuracy of a group will depend strongly on detailed aspects of its social organization. More specifically, group navigation does not only depend on the underlying social relationships, but also on how much weight leading individuals put on following others. Also, we show that groups with certain social structures can compensate better for an increased level of navigational error. The results have broader implications for studies on collective navigation and motion because they show that only by considering a group's social system can we fully elucidate the dynamics and advantages of joint movements. PMID:26063820

  4. Application of X-Ray Pulsar Navigation: A Characterization of the Earth Orbit Trade Space

    Science.gov (United States)

    Yu, Wayne

    2016-01-01

    The potential for pulsars as a navigation source has been studied since their discovery in 1967. X-ray pulsar navigation (XNAV) is a celestial navigation system that uses the consistent timing nature of x-ray photons from milli-second pulsars (MSP) to perform space navigation. By comparing the detected arrival of x-ray photons to a reference database of expected pulsar lightcurve timing models, one can infer a range and range rate measurement based on light time delay. Much of the challenge of XNAV comes from the faint signal, availability, and distant nature of pulsars. This is a study of potential pulsar XNAV measurements to measure extended Kalman filter (EKF) tracking performance with a wide trade space of bounded Earth orbits, using a simulation of existing x-ray detector space hardware. An example of an x-ray detector for XNAV is the NASA Station Explorer for X-ray Timing and Navigation (SEXTANT) mission, a technology demonstration of XNAV set to perform on the International Space Station (ISS) in late 2016early 2017. XNAV hardware implementation is driven by trajectory and environmental influences which add noise to the x-ray pulse signal. In a closed Earth orbit, the radiation environment can exponentially increase the signal noise from x-ray pulsar sources, decreasing the quality and frequency of measurements. The SEXTANT mission in particular improves on the signal to noise ratio by focusing an array of 56 x-ray silicon drift detectors at one pulsar target at a time. This reduces timing glitches and other timing noise contributions from ambient x-ray sources to within a 100 nanosecond resolution. This study also considers the SEXTANT scheduling challenges inherent in a single target observation. Finally, as the navigation sources are now relatively inertial targets, XNAV measurements are also subject to periods of occultation from various celestial bodies. This study focuses on the characterization of these drivers in closed Earth orbits and is not a

  5. Exploring requirements for indoor navigation systems

    OpenAIRE

    Ni, Chunxiao

    2013-01-01

    Indoor navigation has been a subject in ubiquitous computing domain in the past decade. Recently many studies focus on exploring user requirements for indoor navigation systems and make effort in developing effective interactive systems to support indoor navigation. This study aims to find which kind of spatial representation and what orientation cues common users prefer to use for indoor navigation. An experiment was performed to examine the navigation effectiveness and user satisfaction wit...

  6. Conference on Hamiltonian Systems and Celestial Mechanics 2014 & Workshop on Virus Dynamics and Evolution : Extended Abstracts Spring 2014

    CERN Document Server

    Cors, Josep; Llibre, Jaume; Korobeinikov, Andrei

    2015-01-01

    The two parts of the present volume contain extended conference abstracts corresponding to selected talks given by participants at the "Conference on Hamiltonian Systems and Celestial Mechanics 2014" (HAMSYS2014) (15 abstracts) and at the "Workshop on Virus Dynamics and Evolution" (12 abstracts), both held at the Centre de Recerca Matemàtica (CRM) in Barcelona from June 2nd to 6th, 2014, and from June 23th to 27th, 2014, respectively. Most of them are brief articles, containing preliminary presentations of new results not yet published in regular research journals. The articles are the result of a direct collaboration between active researchers in the area after working in a dynamic and productive atmosphere. The first part is about Central Configurations, Periodic Orbits and Hamiltonian Systems with applications to Celestial Mechanics – a very modern and active field of research. The second part is dedicated to mathematical methods applied to viral dynamics and evolution. Mathematical modelling of biologi...

  7. Chaos in navigation satellite orbits caused by the perturbed motion of the Moon

    Science.gov (United States)

    Rosengren, Aaron J.; Alessi, Elisa Maria; Rossi, Alessandro; Valsecchi, Giovanni B.

    2015-06-01

    Numerical simulations carried out over the past decade suggest that the orbits of the Global Navigation Satellite Systems are unstable, resulting in an apparent chaotic growth of the eccentricity. Here, we show that the irregular and haphazard character of these orbits reflects a similar irregularity in the orbits of many celestial bodies in our Solar system. We find that secular resonances, involving linear combinations of the frequencies of nodal and apsidal precession and the rate of regression of lunar nodes, occur in profusion so that the phase space is threaded by a devious stochastic web. As in all cases in the Solar system, chaos ensues where resonances overlap. These results may be significant for the analysis of disposal strategies for the four constellations in this precarious region of space.

  8. Chaos in navigation satellite orbits caused by the perturbed motion of the Moon

    CERN Document Server

    Rosengren, Aaron J; Rossi, Alessandro; Valsecchi, Giovanni B

    2015-01-01

    Numerical simulations carried out over the past decade suggest that the orbits of the Global Navigation Satellite Systems are unstable, resulting in an apparent chaotic growth of the eccentricity. Here we show that the irregular and haphazard character of these orbits reflects a similar irregularity in the orbits of many celestial bodies in our Solar System. We find that secular resonances, involving linear combinations of the frequencies of nodal and apsidal precession and the rate of regression of lunar nodes, occur in profusion so that the phase space is threaded by a devious stochastic web. As in all cases in the Solar System, chaos ensues where resonances overlap. These results may be significant for the analysis of disposal strategies for the four constellations in this precarious region of space.

  9. Multi-Planet Exosystems All Obey Orbital Angular Momentum Quantization per Unit Mass predicted by Quantum Celestial Mechanics (QCM

    Directory of Open Access Journals (Sweden)

    Potter F.

    2013-07-01

    Full Text Available Quantum celestial mechanics (QCM predicts that all orbiting bodies in gravitationally bound systems exhibit the quantization of orbital angular momentum per unit mass. I show that the 15 known multi-planet systems with four or more planets obey this QCM prediction. This angular momentum constraint could be the explanation for their orbital stability for billions of years, suggesting that viable models of the formation and evolution of gravitational systems must include QCM.

  10. On the Astronomical Collection of the Przemyslid Royal Court. I. The Celestial Globe now in Bernkastel-Kues

    Czech Academy of Sciences Publication Activity Database

    Hadravová, Alena; Hadrava, Petr

    Wien : Fassbaender, 2012 - (Simek, R.; Klein, M.), s. 111-121, 274-281 ISBN 978-3-902575-47-0. [Johannes von Gmunden (ca. 1385-1442). Zwischen Astronomie und Astrologie. Gmunden (AT), 17.06.2012-19.06.2012] R&D Projects: GA ČR(CZ) GAP405/11/0034 Institutional support: RVO:68378114 ; RVO:67985815 Keywords : history of medieval astronomy * celestial globes * Ptolemaic constellations Subject RIV: AB - History

  11. On the Astronomical Collection of the Przemyslid Royal Court. II. Digital Facsimile of the Bernkastel-Kues Celestial Globe

    Czech Academy of Sciences Publication Activity Database

    Hadrava, Petr; Hadravová, Alena

    Wien : Fassbaender, 2012 - (Simek, R.; Klein, M.), s. 123-130, 282-284 ISBN 978-3-902575-47-0. [Johannes von Gmunden (ca. 1385-1442). Zwischen Astronomie und Astrologie. Gmunden (AT), 17.06.2012-19.06.2012] R&D Projects: GA ČR(CZ) GAP405/11/0034 Institutional support: RVO:67985815 ; RVO:68378114 Keywords : history of medieval astronomy * celestial globes * Ptolemaic constellations Subject RIV: AB - History

  12. Søgning og navigation

    DEFF Research Database (Denmark)

    Grauballe, Henning; Strunck, Kirsten Marie

    6 udvalgte testposter undersøges i 97 danske folkebibliotekers webkataloger med henblik på at afdække, hvordan disse testposters kontrollerede data udnyttes som hyperlinks til navigation og til videresøgning på ”Noget der ligner”. Undersøgelsen viser, at webkatalogerne især fokuserer på at udnytte...... opstillingsdata og udvalgte emnedata til navigation. Dermed udnyttes det samlede potentiale i de kontrollerede data ikke til at imødekomme brugernes forventninger til navigation ved hjælp af hyperlinks på Web’en. Undersøgelsen indikerer desuden, at der er en tæt sammenhæng mellem det konkrete bibliotekssystem...

  13. GPS Navigation and Tracking Device

    Directory of Open Access Journals (Sweden)

    Yahya Salameh Khraisat

    2011-10-01

    Full Text Available Since the introduction of GPS Navigation systems in the marketplace, consumers and businesses have been coming up with innovative ways to use the technology in their everyday life. GPS Navigation and Tracking systems keep us from getting lost when we are in strange locations, they monitor children when they are away from home, keep track of business vehicles and can even let us know where a philandering partner is at all times. Because of this we attend to build a GPS tracking device to solve the mentioned problems. Our work consists of the GPS module that collects data from satellites and calculates the position information before transmitting them to the user’s PC (of Navigation system or observers (of Tracking System using wireless technology (GSM.

  14. Surgical navigation in oral implantology.

    Science.gov (United States)

    Miller, Robert J; Bier, Jurgen

    2006-03-01

    The ability to generate 3-dimensional volumetric images of the maxillofacial area has allowed surgeons to evaluate anatomy before surgery and plan for the placement of implants in ideal positions. However, the ability to transfer that information to surgical reality has been the most challenging part of implant dentistry. With the advent of computer-assisted surgery, the surgeon may now navigate through the entire implant procedure with extremely high accuracy. A new portable laptop navigated system for oral implantology is discussed as an adjunct for complex implant cases. PMID:16569960

  15. Observability of Inertial Navigation System

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    To improve the observability of strapdown inertial navigation system and the effectiveness of Kalman filter in the navigation system, the method of estimating the observability is analyzed based on eigenvalues and eigenvectors which are proved to be availabe, on this basis two-position alignment technigue is applied. The simulation shows that two-position alignment really makes the system's observability change from being incomplete to being complete, and the test method based on eigenvalues and eigenvectors is available to determine the observability of every state vector.

  16. Navigation with a visual memory

    OpenAIRE

    Remazeilles, Anthony

    2004-01-01

    This work deals with autonomous robotic navigation. A robotic system that moves on its own must be able to localise itself in the environment, so as to define a path to follow, and also to control its motion in order to reach a desired position. A vision based-approach is chosen, by onsidering robotic systems with an on-board camera. The navigation space is represented in a topological way by an image database acquired during a learning step. Thus, the robot localisation is directly related t...

  17. The constructional conception of the effectiveness of navigational service rising for navigation on inland water routes

    OpenAIRE

    I. V. Tykhonov

    2010-01-01

    Constructional conception of rising of the effectiveness of navigational service on inland water routes is described. The article demonstrates that using of this conception and informational recourses permit to raise the effectiveness of navigational service of safety of navigation

  18. Non-parametric PSF estimation from celestial transit solar images using blind deconvolution

    Science.gov (United States)

    González, Adriana; Delouille, Véronique; Jacques, Laurent

    2016-01-01

    Context: Characterization of instrumental effects in astronomical imaging is important in order to extract accurate physical information from the observations. The measured image in a real optical instrument is usually represented by the convolution of an ideal image with a Point Spread Function (PSF). Additionally, the image acquisition process is also contaminated by other sources of noise (read-out, photon-counting). The problem of estimating both the PSF and a denoised image is called blind deconvolution and is ill-posed. Aims: We propose a blind deconvolution scheme that relies on image regularization. Contrarily to most methods presented in the literature, our method does not assume a parametric model of the PSF and can thus be applied to any telescope. Methods: Our scheme uses a wavelet analysis prior model on the image and weak assumptions on the PSF. We use observations from a celestial transit, where the occulting body can be assumed to be a black disk. These constraints allow us to retain meaningful solutions for the filter and the image, eliminating trivial, translated, and interchanged solutions. Under an additive Gaussian noise assumption, they also enforce noise canceling and avoid reconstruction artifacts by promoting the whiteness of the residual between the blurred observations and the cleaned data. Results: Our method is applied to synthetic and experimental data. The PSF is estimated for the SECCHI/EUVI instrument using the 2007 Lunar transit, and for SDO/AIA using the 2012 Venus transit. Results show that the proposed non-parametric blind deconvolution method is able to estimate the core of the PSF with a similar quality to parametric methods proposed in the literature. We also show that, if these parametric estimations are incorporated in the acquisition model, the resulting PSF outperforms both the parametric and non-parametric methods.

  19. Latest Moon gravity field solutions from GRAIL data using the Celestial Mechanics Approach

    Science.gov (United States)

    Bertone, Stefano; Arnold, Daniel; Jäggi, Adrian; Beutler, Gerhard; Mervart, Leos; Meyer, Ulrich

    2016-04-01

    The NASA mission GRAIL inherits its concept from the GRACE mission to determine the gravity field of the Moon. The use of inter-satellite Ka-band range-rate (KBRR) observations enables data acquisition even when the spacecraft are not tracked from the Earth. The data allows for a highly accurate estimation of the lunar gravity field on both sides of the Moon, which is leading to huge improvements in our understanding of its internal structure and thermal evolution. In this presentation we discuss the latest GRAIL-based lunar gravity fields generated with the Celestial Mechanics Approach using the Bernese GNSS Software. We recently presented our solutions up to d/o 200, where KBRR observations and position data (GNI1B products) were used to solve for the lunar gravity field parameters in a generalized orbit determination problem. As a further extension of our processing, the GNI1B positions are now replaced by the original Doppler observations of the Deep Space Network (DSN) to allow for a completely independent determination of the lunar gravity field. Based on Doppler data, we perform orbit determination by solving six initial orbital elements, dynamical parameters, and stochastic parameters in daily arcs using least-squares adjustment. The pseudo-stochastic parameters are estimated to absorb deficiencies in our dynamical modeling (e.g. due to non-gravitational forces). Doppler and KBRR data are then used together with an appropriate weighting for a combined orbit determination process. We present our latest results in the orbit determination of GRAIL over the primary mission phase (PM, March-May 2012) and our first lunar gravity fields based on Doppler and KBRR observations. We compare all of our results from the PM with the most recent lunar gravity field models released by other groups, as well as their consistency with topography-induced gravity.

  20. Conceptual Grounds of Navigation Safety

    Directory of Open Access Journals (Sweden)

    Vladimir Torskiy

    2016-04-01

    Full Text Available The most important global problem being solved by the whole world community nowadays is to provide sustainable mankind development. Recent research in the field of sustainable development states that civilization safety is impossible without transfer sustainable development. At the same time, sustainable development (i.e. preservation of human culture and biosphere is impossible as a system that serves to meet economical, cultural, scientific, recreational and other human needs without safety. Safety plays an important role in sustainable development goals achievement. An essential condition of effective navigation functioning is to provide its safety. The “prescriptive” approach to the navigation safety, which is currently used in the world maritime field, is based on long-term experience and ship accidents investigation results. Thus this approach acted as an the great fact in reduction of number of accidents at sea. Having adopted the International Safety Management Code all the activities connected with navigation safety problems solution were transferred to the higher qualitative level. Search and development of new approaches and methods of ship accidents prevention during their operation have obtained greater importance. However, the maritime safety concept (i.e. the different points on ways, means and methods that should be used to achieve this goal hasn't been formed and described yet. The article contains a brief review of the main provisions of Navigation Safety Conceptions, which contribute to the number of accidents and incidents at sea reduction.

  1. Navigation system for interstitial brachytherapy

    International Nuclear Information System (INIS)

    The purpose of the stud was to develop a computed tomography (CT) based electromagnetic navigation system for interstitial brachytherapy. This is especially designed for situations when needles have to be positioned adjacent to or within critical anatomical structures. In such instances interactive 3D visualisation of the needle positions is essential. The material consisted of a Polhemus electromagnetic 3D digitizer, a Pentium 200 MHz laptop and a voice recognition for continuous speech. In addition, we developed an external reference system constructed of Perspex which could be positioned above the tumour region and attached to the patient using a non-invasive fixation method. A specially designed needle holder and patient bed were also developed. Measurements were made on a series of phantoms in order to study the efficacy and accuracy of the navigation system. The mean navigation accuracy of positioning the 20.0 cm length metallic needles within the phantoms was in the range 2.0-4.1 mm with a maximum of 5.4 mm. This is an improvement on the accuracy of a CT-guided technique which was in the range 6.1-11.3 mm with a maximum of 19.4 mm. The mean reconstruction accuracy of the implant geometry was 3.2 mm within a non-ferromagnetic environment. We found that although the needles were metallic this did not have a significant influence. We also found for our experimental setups that the CT table and operation table non-ferromagnetic parts had no significant influence on the navigation accuracy. This navigation system will be a very useful clinical tool for interstitial brachytherapy applications, particularly when critical structures have to be avoided. It also should provide a significant improvement on our existing technique

  2. Relativistic navigation a theoretical foundation

    CERN Document Server

    Turyshev, S G

    1996-01-01

    We present a theoretical foundation for relativistic astronomical measurements in curved space-time. In particular, we discuss a new iterative approach for describing the dynamics of an astronomical N-body system. To do this, we generalize the Fock-Chandrasekhar method of the weak-field and slow-motion approximation (WFSMA) and develop a theory of relativistic reference frames (RF) for a gravitationally bounded many-extended-body problem. In any proper RF constructed in the immediate vicinity of an arbitrary body, the N-body solutions of the gravitational field equations are presented as a sum of the Riemann-flat inertial space-time, the gravitational field generated by the body itself, the unperturbed solutions for each body in the system transformed to the coordinates of this proper RF, and the gravitational interaction term. We develop the basic concept of a general theory of the celestial RFs applicable to a wide class of metric theories of gravity with an arbitrary model of matter distribution. We apply ...

  3. 33 CFR 401.54 - Interference with navigation aids.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Interference with navigation aids. 401.54 Section 401.54 Navigation and Navigable Waters SAINT LAWRENCE SEAWAY DEVELOPMENT CORPORATION... with navigation aids. (a) Aids to navigation shall not be interfered with or used as moorings. (b)...

  4. 33 CFR 67.35-10 - Private aids to navigation.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Private aids to navigation. 67.35-10 Section 67.35-10 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY AIDS TO NAVIGATION AIDS TO NAVIGATION ON ARTIFICIAL ISLANDS AND FIXED STRUCTURES Applications §...

  5. 33 CFR 100.45 - Establishment of aids to navigation.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Establishment of aids to navigation. 100.45 Section 100.45 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND... navigation. The District Commander will establish and maintain only those aids to navigation necessary...

  6. Navigation in Cross-cultural business relationships

    DEFF Research Database (Denmark)

    Andersen, Poul Houman

    2001-01-01

    Cross-cultural business navigation concerns the process of handling the complexity of several interacting cultural spheres of influence......Cross-cultural business navigation concerns the process of handling the complexity of several interacting cultural spheres of influence...

  7. Indirect assessment of web navigation success

    OpenAIRE

    Gwizdka, Jacek; Spence, Ian

    2005-01-01

    Despite much research on hypertext and web navigation, relatively little is known about the relationship between web navigation strategies and success. We present two exploratory studies designed to explore the relationships between several web navigation metrics that are based on similarity to an optimal path to predict task success. The data suggest that the relationships between these measures depend on the particular web navigation task.

  8. Sniffing Around for Providing Navigation Assistance

    OpenAIRE

    Herder, E.

    2004-01-01

    In this paper we describe an approach to adaptive navigation assistance that is meant to enhance a user’s information scent. The navigation assistance is composed of a combination of predictive user navigation modeling and common information retrieval methods. Besides assistance in forward browsing, the assistant helps users in deciding when to switch to searching or backtracking, while taking their navigation preferences into account.

  9. Novel Environmental Features for Robust Multisensor Navigation

    OpenAIRE

    Walter, D. J.; Groves, P. D.; Mason, R J; Harrison, J.; J. Woodward; Wright, P

    2013-01-01

    Many navigation techniques have now become so reliant on GNSS that there is no back up when there is limited or no signal reception. If there is interference, intentional or otherwise, with the signal, navigation could be lost or become misleading [1]. Other navigation techniques harness different technologies such as Wi-Fi [2], eLoran and inertial navigation. However, each of these techniques has its own limitations, such as coverage, degradation in urban areas or solution drift [3]. Therefo...

  10. Navigation based on symbolic space models

    OpenAIRE

    Baras, Karolina; Moreira, Adriano; Meneses, Filipe

    2010-01-01

    Existing navigation systems are very appropriate for car navigation, but lack support for convenient pedestrian navigation and cannot be used indoors due to GPS limitations. In addition, the creation and the maintenance of the required models are costly and time consuming, and are usually based on proprietary data structures. In this paper we describe a navigation system based on a human inspired symbolic space model. We argue that symbolic space models are much easier...

  11. Advances in GRAIL Gravity Field Determination Using the Celestial Mechanics Approach

    Science.gov (United States)

    Bertone, S.; Arnold, D.; Jaeggi, A.; Beutler, G.; Mervart, L.

    2015-12-01

    The NASA mission GRAIL inherits its concept from the GRACE mission to determine the gravity field of the Moon. The use of inter-satellite Ka-band range-rate (KBRR) observations enables data acquisition even when the spacecraft are not tracked from the Earth. The data allows for a highly accurate estimation of the lunar gravity field on both sides of the Moon, which is leading to huge improvements in our understanding of its internal structure and thermal evolution. In this presentation we discuss the latest GRAIL-based lunar gravity fields generated with the Celestial Mechanics Approach using the Bernese GNSS Software. We present our recent solutions up to d/o 200, where KBRR observations and position data (GNI1B products) were used to solve for the lunar gravity field parameters in a generalized orbit determination problem. We detail our parametrization in terms of pseudo-stochastic pulses and empirical accelerations, which allows for high quality results even while using a simple model of non-gravitational forces and pre-GRAIL a priori fields. Moreover, we present our latest advances towards the computation of a lunar gravity field with improved spatial resolution.As a further extension of our processing, the GNI1B positions are replaced by the original Doppler observations of the Deep Space Network (DSN) to allow for a completely independent determination of the lunar gravity field. Based on Doppler data, we perform orbit determination by solving six initial orbital elements, dynamical parameters, and stochastic parameters in daily arcs using least squares-adjustment. The pseudo-stochastic parameters are estimated to absorb deficiencies in our dynamical modeling (e.g. due to non-gravitational forces). DSN Doppler and KBRR data are then used together with an appropriate weighting for a combined orbit determination process. We present our latest results in the orbit determination of GRAIL over the primary mission phase (PM, March-May 2012) and eventually present

  12. Observability during planetary approach navigation

    Science.gov (United States)

    Bishop, Robert H.; Burkhart, P. Daniel; Thurman, Sam W.

    1993-01-01

    The objective of the research is to develop an analytic technique to predict the relative navigation capability of different Earth-based radio navigation measurements. In particular, the problem is to determine the relative ability of geocentric range and Doppler measurements to detect the effects of the target planet gravitational attraction on the spacecraft during the planetary approach and near-encounter mission phases. A complete solution to the two-dimensional problem has been developed. Relatively simple analytic formulas are obtained for range and Doppler measurements which describe the observability content of the measurement data along the approach trajectories. An observability measure is defined which is based on the observability matrix for nonlinear systems. The results show good agreement between the analytic observability analysis and the computational batch processing method.

  13. 06421 Abstracts Collection -- Robot Navigation

    OpenAIRE

    Fekete, Sándor; Fleischer, Rudolf; Klein, Rolf; Lopez-Ortiz, Alejandro

    2007-01-01

    From 15.10.06 to 20.10.06, the Dagstuhl Seminar 06421 ``Robot Navigation''generate automatically was held in the International Conference and Research Center (IBFI), Schloss Dagstuhl. During the seminar, several participants presented their current research, and ongoing work and open problems were discussed. Abstracts of the presentations given during the seminar as well as abstracts of seminar results and ideas are put together in this paper. The first section describes the...

  14. Interplanetary spacecraft navigation using pulsars

    OpenAIRE

    Deng, X. P.; Hobbs, G.; You, X. P.; M. T. Li; Keith, M. J.; Shannon, R. M.; Coles, W.; Manchester, R. N.; J.H. Zheng; Yu, X. Z.; Gao, D.; Wu, X; Chen, D.

    2013-01-01

    We demonstrate how observations of pulsars can be used to help navigate a spacecraft travelling in the solar system. We make use of archival observations of millisecond pulsars from the Parkes radio telescope in order to demonstrate the effectiveness of the method and highlight issues, such as pulsar spin irregularities, which need to be accounted for. We show that observations of four millisecond pulsars every seven days using a realistic X-ray telescope on the spacecraft throughout a journe...

  15. Safety effects of navigation systems.

    OpenAIRE

    2009-01-01

    Increasing numbers of drivers are using navigation systems in their cars. The advantages to the user are obvious: you can get to your destination via the fastest and shortest route. This reduces stress and exposure to other traffic. However, there are also some (unintended) negative effects. For example, using the system while driving can distract your attention from other traffic. The system sometimes directs traffic through small centres of habitation or along unsuitable roads. Moreover, ti...

  16. Robotic perception for autonomous navigation

    OpenAIRE

    Furlan,

    2014-01-01

    This thesis presents the research work the author carried on during his PhD on the topic of robotic perception for autonomous navigation. In particular, the efforts focus on the Self-Localization, Scene Understanding and Object Detection and Tracking problems, proposing for each of these three topics one or more approaches that present an improvement over the state-of-the-art. In some cases the proposed approaches mutually exploit the generated information to improve the quality of the final ...

  17. 06421 Executive Summary -- Robot Navigation

    OpenAIRE

    Fekete, Sándor; Fleischer, Rudolf; Klein, Rolf; Lopez-Ortiz, Alejandro

    2007-01-01

    For quite a number of years, researchers from various fields have studied problems motivated by Robot Navigation. People in Online Algorithms have developed strategies that can deal with the inherent lack of information an autonomous robot encounters, as it sets out to perform a task in an unknown environment. Computational Geometers have obtained many results on the efficient planning of collision-free motions, and on visibility problems. Scientists and engineers in Robotics have perfected r...

  18. Navigation in diagnosis and therapy

    International Nuclear Information System (INIS)

    Image-guided navigation for surgery and other therapeutic interventions has grown in importance in recent years. During image-guided navigation a target is detected, localized and characterized for diagnosis and therapy. Thus, images are used to select, plan, guide and evaluate therapy, thereby reducing invasiveness and improving outcomes. A shift from traditional open surgery to less-invasive image-guided surgery will continue to impact the surgical marketplace. Increases in the speed and capacity of computers and computer networks have enabled image-guided interventions. Key elements in image navigation systems are pre-operative 3D imaging (or real-time image acquisition), a graphical display and interactive input devices, such as surgical instruments with light emitting diodes (LEDs). CT and MRI, 3D imaging devices, are commonplace today and 3D images are useful in complex interventions such as radiation oncology and surgery. For example, integrated surgical imaging workstations can be used for frameless stereotaxy during neurosurgical interventions. In addition, imaging systems are being expanded to include decision aids in diagnosis and treatment. Electronic atlases, such as Voxel Man or others derived from the Visible Human Project, combine a set of image data with non-image knowledge such as anatomic labels. Robot assistants and magnetic guidance technology are being developed for minimally invasive surgery and other therapeutic interventions. Major progress is expected at the interface between the disciplines of radiology and surgery where imaging, intervention and informatics converge

  19. Quantum and Post-Newtonian Effects in the Anomalistic Period and the Mean Motion of Celestial Bodies

    CERN Document Server

    Haranas, Ioannis; Gkigkitzis, Ioannis; Kotsireas, Ilias

    2015-01-01

    We study the motion of a secondary celestial body under the influence of the corrected gravitational force of a primary. We study the effect of quantum and relativistic corrections to the gravitational potential of a primary body acting on the orbiting body. More specifically, two equations are derived to approximate the perigee/perihelion/periastron time rate of change and its total variation over one revolution (i.e., the difference between the anomalistic period and the Keplerian period) under the influence of the quantum as well as post- Newtonian accelerations. Numerical results have been obtained for the artificial Earth satellite Molnya, Mercury, and, finally, the for the HW Vir c, planetary companion.

  20. Gaia, Helios, Selene and Ouranos: the three principal celestial bodies and the sky in the ancient Greek cosmogony

    Science.gov (United States)

    Theodossiou, Efstratios; Manimanis, Vassilios N.; Dimitrijević, Milan S.; Mantarakis, Petros

    In this article we consider the role of the three principal celestial bodies, the Earth (Gaia), the Sun (Helios) and the Moon (Selene), as well as the Sky (Ouranos) in the ancient Greek cosmogony. This is done by the analysis of antique Greek texts like Orphic Hymns and the literary remains of the writers and philosophers like Aeschylus, (Pseudo) Apollodorus, Apollonius Rhodius, Aristotle, Euripides, Hesiod, Homer, Hyginus, Nonnus, Pausanias, Pindar and Sophocles, as well as by the analysis of texts of Roman writers like Cicero, Ovid and Pliny.

  1. Effect of a large-scale distance variation of gravitational constant on the orbital elements of celestial bodies

    International Nuclear Information System (INIS)

    The effects of the variation of the gravitational constant with distance on the variation of the orbital elements of celestial objects are examined. The theoretical results show clearly that the large distance variation of the gravitational constant results in the periodic variation of the semi-major axis, eccentricity, longitude of the perihelion and the mean longitude, but it results in the secular variation of the longitude of the perihelion and the mean longitude, no secular variation for other orbital elements. As an example, the effects on four planets are estimated. Discussion and conclusion are drawn.

  2. Navigation.

    Science.gov (United States)

    Wellman, Bruce; Lipton, Laura

    2000-01-01

    Teachers' quests for more data-based planning, problem solving, and decision making often stumble against limited capacities for engaging in thoughtful interactions, with groups typically lacking process tools, collaborative communication skills, and reflective habits. This article presents a three-phase model for guiding data-driven dialogue in…

  3. Relativistic Navigation: A Theoretical Foundation

    Science.gov (United States)

    Turyshev, Slava G.

    1996-01-01

    We present a theoretical foundation for relativistic astronomical measurements in curved space-time. In particular, we discuss a new iterative approach for describing the dynamics of an isolated astronomical N-body system in metric theories of gravity. To do this, we generalize the Fock-Chandrasekhar method of the weak-field and slow-motion approximation (WFSMA) and develop a theory of relativistic reference frames (RF's) for a gravitationally bounded many-extended-body problem. In any proper RF constructed in the immediate vicinity of an arbitrary body, the N-body solutions of the gravitational field equations are formally presented as a sum of the Riemann-flat inertial space-time, the gravitational field generated by the body itself, the unperturbed solutions for each body in the system transformed to the coordinates of this proper RF, and the gravitational interaction term. We develop the basic concept of a general WFSMA theory of the celestial RF's applicable to a wide class of metric theories of gravity and an arbitrary model of matter distribution. We apply the proposed method to general relativity. Celestial bodies are described using a perfect fluid model; as such, they possess any number of internal mass and current multipole moments that explicitly characterize their internal structures. The obtained relativistic corrections to the geodetic equations of motion arise because of a coupling of the bodies' multiple moments to the surrounding gravitational field. The resulting relativistic transformations between the different RF's extend the Poincare group to the motion of deformable self-gravitating bodies. Within the present accuracy of astronomical measurements we discuss the properties of the Fermi-normal-like proper RF that is defined in the immediate vicinity of the extended compact bodies. We further generalize the proposed approximation method and include two Eddington parameters (gamma, Beta). This generalized approach was used to derive the

  4. Cooperative navigation and localization for multiple UUVs

    Science.gov (United States)

    Zhang, Li-Chuan; Xu, De-Min; Liu, Ming-Yong; Yan, Wei-Sheng

    2009-09-01

    The authors proposed a moving long baseline algorithm based on the extended Kalman filter (EKF) for cooperative navigation and localization of multi-unmanned underwater vehicles (UUVs). Research on cooperative navigation and localization for multi-UUVs is important to solve navigation problems that restrict long and deep excursions. The authors investigated improvements in navigation accuracy. In the moving long base line (MLBL) structure, the master UUV is equipped with a high precision navigation system as a node of the moving long baseline, and the slave UUV is equipped with a low precision navigation system. They are both equipped with acoustic devices to measure relative location. Using traditional triangulation methods to calculate the position of the slave UUV may cause a faulty solution. An EKF was designed to solve this, combining the proprioceptive and exteroceptive sensors. Research results proved that the navigational accuracy is improved significantly with the MLBL method based on EKF.

  5. Spatial navigation in young versus older adults

    Directory of Open Access Journals (Sweden)

    Ivana Gazova

    2013-12-01

    Full Text Available Older age is associated with changes in the brain, including the medial temporal lobe, which may result in mild spatial navigation deficits, especially in allocentric navigation. The aim of the study was to characterize the profile of real-space allocentric (world-centered, hippocampus dependent and egocentric (body-centered, parietal lobe dependent navigation and learning in young vs. older adults, and to assess a possible influence of gender. We recruited healthy participants without cognitive deficits on standard neuropsychological testing, white matter lesions or pronounced hippocampal atrophy: 24 young participants (18-26 years old and 44 older participants stratified as participants 60-70 years old (n=24 and participants 71-84 years old (n=20. All underwent spatial navigation testing in the real-space human analog of the Morris Water Maze, which has the advantage of assessing separately allocentric and egocentric navigation and learning. Of the 8 consecutive trials, trials 2-8 were used to reduce bias by a rebound effect (more dramatic changes in performance between trials 1 and 2 relative to subsequent trials. The participants who were 71-84 years old (p< .001, but not those 60-70 years old, showed deficit in allocentric navigation compared to the young participants. There were no differences in egocentric navigation. All three groups showed spatial learning effect (p´s ≤.01. There were no gender differences in spatial navigation and learning. The linear regression limited to older participants showed linear (β=0.30, p=.045 and quadratic (β=0.30, p=.046 effect of age on allocentric navigation. There was no effect of age on egocentric navigation. These results demonstrate that navigation deficits in older age may be limited to allocentric navigation, whereas egocentric navigation and learning may remain preserved. This specific pattern of spatial navigation impairment may help differentiate normal aging from prodromal Alzheimer

  6. Honeybees as a model for the study of visually guided flight, navigation, and biologically inspired robotics.

    Science.gov (United States)

    Srinivasan, Mandyam V

    2011-04-01

    Research over the past century has revealed the impressive capacities of the honeybee, Apis mellifera, in relation to visual perception, flight guidance, navigation, and learning and memory. These observations, coupled with the relative ease with which these creatures can be trained, and the relative simplicity of their nervous systems, have made honeybees an attractive model in which to pursue general principles of sensorimotor function in a variety of contexts, many of which pertain not just to honeybees, but several other animal species, including humans. This review begins by describing the principles of visual guidance that underlie perception of the world in three dimensions, obstacle avoidance, control of flight speed, and orchestrating smooth landings. We then consider how navigation over long distances is accomplished, with particular reference to how bees use information from the celestial compass to determine their flight bearing, and information from the movement of the environment in their eyes to gauge how far they have flown. Finally, we illustrate how some of the principles gleaned from these studies are now being used to design novel, biologically inspired algorithms for the guidance of unmanned aerial vehicles. PMID:21527730

  7. The Sun, the Moon and Firmament in Chukchi Mythology and on the Relations of Celestial Bodies and Sacrifices

    Directory of Open Access Journals (Sweden)

    Ülo Siimets

    2006-01-01

    Full Text Available This article gives a brief overview of the most common Chukchi myths, notions and beliefs related to celestial bodies at the end of the 19th and during the 20th century. The firmament of Chukchi world view is connected with their main source of subsistence – reindeer herding. Chukchis are one of the very few Siberian indigenous people who have preserved their religion. Similarly to many other nations, the peoples of the Far North as well as Chukchis personify the Sun, the Moon and stars. The article also points out thesimilarities between Chukchi notions and these of other peoples. Till now Chukchi reindeer herders seek the supposed help or influence of a constellation or planet when making important sacrifices (for example, offering sacrifices in a full moon. According to the Chukchi religion the most important celestial character is the Sun. It is spoken of as an individual being (vaśrgśn. In addition to the Sun, the Creator, Dawn, Zenith, Midday and the North Star also belong to the ranks of special (superior beings. The Moon in Chukchi mythology is a man and a being in one person. It is as the ketlja (evil spiritof the Sun. Chukchi myths about several stars (such as the North Star and Betelgeuse resemble to a great extent these of other peoples.

  8. Manifestation of central symmetry of the celestial sphere in the mutual disposition and luminosity of the Quasars

    CERN Document Server

    Kudriavtcev, Iurii

    2010-01-01

    We performed the check of supposition about the possibility of manifestation of the previously observed phenomenon of central symmetry of the celestial sphere through existence of the opposite quasars. We discovered the existence of some pairs of quasars located opposite each other with close by form profiles magnitudes of luminosity in the ranges u, g, r, i, z, when correlation coefficient close to 1. We discovered that the percentage of the pairs with correlation coefficients Rxy>0.98 for the opposite located quasars is significantly higher than that for the random pairs. The analysis of the dependence of this exceedance from the artificial breaking of the central symmetry has shown, that it practically disappears with symmetry breaking by more than 0.05 degrees. Thus we can confirmed the manifestation of the central symmetry of celestial sphere through existence of the central symmetrical pairs of quasars, which can be interpreted as the pairs of images of the same object. We shown the possibility of a the...

  9. An analytical model for the celestial distribution of polarized light, accounting for polarization singularities, wavelength and atmospheric turbidity

    Science.gov (United States)

    Wang, Xin; Gao, Jun; Fan, Zhiguo; Roberts, Nicholas W.

    2016-06-01

    We present a computationally inexpensive analytical model for simulating celestial polarization patterns in variable conditions. We combine both the singularity theory of Berry et al (2004 New J. Phys. 6 162) and the intensity model of Perez et al (1993 Sol. Energy 50 235–245) such that our single model describes three key sets of data: (1) the overhead distribution of the degree of polarization as well as the existence of neutral points in the sky; (2) the change in sky polarization as a function of the turbidity of the atmosphere; and (3) sky polarization patterns as a function of wavelength, calculated in this work from the ultra-violet to the near infra-red. To verify the performance of our model we generate accurate reference data using a numerical radiative transfer model and statistical comparisons between these two methods demonstrate no significant difference in almost all situations. The development of our analytical model provides a novel method for efficiently calculating the overhead skylight polarization pattern. This provides a new tool of particular relevance for our understanding of animals that use the celestial polarization pattern as a source of visual information.

  10. Emergency Navigation without an Infrastructure

    Directory of Open Access Journals (Sweden)

    Erol Gelenbe

    2014-08-01

    Full Text Available Emergency navigation systems for buildings and other built environments, such as sport arenas or shopping centres, typically rely on simple sensor networks to detect emergencies and, then, provide automatic signs to direct the evacuees. The major drawbacks of such static wireless sensor network (WSN-based emergency navigation systems are the very limited computing capacity, which makes adaptivity very difficult, and the restricted battery power, due to the low cost of sensor nodes for unattended operation. If static wireless sensor networks and cloud-computing can be integrated, then intensive computations that are needed to determine optimal evacuation routes in the presence of time-varying hazards can be offloaded to the cloud, but the disadvantages of limited battery life-time at the client side, as well as the high likelihood of system malfunction during an emergency still remain. By making use of the powerful sensing ability of smart phones, which are increasingly ubiquitous, this paper presents a cloud-enabled indoor emergency navigation framework to direct evacuees in a coordinated fashion and to improve the reliability and resilience for both communication and localization. By combining social potential fields (SPF and a cognitive packet network (CPN-based algorithm, evacuees are guided to exits in dynamic loose clusters. Rather than relying on a conventional telecommunications infrastructure, we suggest an ad hoc cognitive packet network (AHCPN-based protocol to adaptively search optimal communication routes between portable devices and the network egress nodes that provide access to cloud servers, in a manner that spares the remaining battery power of smart phones and minimizes the time latency. Experimental results through detailed simulations indicate that smart human motion and smart network management can increase the survival rate of evacuees and reduce the number of drained smart phones in an evacuation process.

  11. 33 CFR 162.240 - Tongass Narrows, Alaska; navigation.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Tongass Narrows, Alaska; navigation. 162.240 Section 162.240 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY INLAND WATERWAYS NAVIGATION REGULATIONS § 162.240...

  12. 33 CFR 401.97 - Closing procedures and ice navigation.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Closing procedures and ice navigation. 401.97 Section 401.97 Navigation and Navigable Waters SAINT LAWRENCE SEAWAY DEVELOPMENT CORPORATION, DEPARTMENT OF TRANSPORTATION SEAWAY REGULATIONS AND RULES Regulations Navigation...

  13. Youth Mobilisation as Social Navigation

    DEFF Research Database (Denmark)

    Vigh, Henrik Erdman

    2010-01-01

    This article sheds light on the mobilisation of young people into conflict. It argues that warfare constitutes a terrain of possibility for urban youth in Guinea‑Bissau, and shows how they navigate war as an event by tactically manoeuvring within the social ties and options that arise in such sit...

  14. PNP: mining of profile navigational patterns

    Science.gov (United States)

    Li, Hua-Fu; Shan, Man-Kwan

    2002-03-01

    Web usage mining is a key knowledge discovery research and as such has been well researched. So far, this research has focused mainly on databases containing access log data only. However, many real-world databases contain users profile data and current solutions for this situation are still insufficient. In this paper we have a large database containing of user profile information together with user web-pages navigation patterns. The user profile data includes quantitative attributes, such as salary or age, and categorical attributes, such as sex or marital status. We introduce the concept of profile navigation patterns, which discusses the problem of relating user profile information to navigational behavior. An example of such profile navigation pattern might be 20% of married people between age 25 and 30 have the similar navigational behavior , where a, c, h, i, l are web pages in a web site. The navigation patterns may contain the generic traversal behavior, e.g. trend to backward moves, cycles etc. The objective of mining profile navigation patterns is to identify browser profile for web personalization. We give an algorithm for mining such profile navigation patterns. Our method (algorithm PNP) can discover profile navigation patterns efficiently. We also present new inclination measurements to identify the interesting profile navigational patterns. Experimental results show the efficiency and scalability of PNP.

  15. 33 CFR 207.169 - Oklawaha River, navigation lock and dam at Moss Bluff, Fla.; use, administration, and navigation.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Oklawaha River, navigation lock and dam at Moss Bluff, Fla.; use, administration, and navigation. 207.169 Section 207.169 Navigation and Navigable Waters CORPS OF ENGINEERS, DEPARTMENT OF THE ARMY, DEPARTMENT OF DEFENSE...

  16. Intelligent navigation and multivehicle coordination

    Science.gov (United States)

    McKay, Mark D.; Anderson, Matthew O.; Kinoshita, Robert A.; Flann, Nicholas S.

    1999-07-01

    The Idaho National Engineering and Environmental Laboratory (INEEL) and Utah State University's Center for Self-Organizing and Intelligent Systems have developed a team of autonomous robotic vehicles. This paper discusses the development of a strategy that uses a sophisticated, highly intelligent sensor platform to allow centralized coordination between smaller and inexpensive robots. The three components of the multi-agent cooperative scheme are small-scale robots, large-scale robots, and the central control station running a mission and path- planning software. The smaller robots are used for activities where the probability of loss increases, such as Unexploded Ordnance (UXO) or mine detonation. The research is aimed at building simple, inexpensive multi-agent vehicles and an intelligent navigation and multi-vehicle coordination system suitable for UXO, environmental remediation or mine detection. These simplified robots are capable of conducting hunting missions using low-cost positioning sensors and intelligent algorithms. Additionally, a larger sensor-rich intelligent system capable of transporting smaller units to outlying remote sites has been developed. The larger system interfaces to the central control station and provides navigation assistance to multiple low-cost vehicles. Finally, mission and path-planning software serves as the operator control unit, allowing central data collection, map creation and tracking, and an interface to the larger system as well as each smaller unit. The power of this scheme is the ability to scale to the appropriate level for the complexity of the mission.

  17. Optic flow and autonomous navigation.

    Science.gov (United States)

    Campani, M; Giachetti, A; Torre, V

    1995-01-01

    Many animals, especially insects, compute and use optic flow to control their motion direction and to avoid obstacles. Recent advances in computer vision have shown that an adequate optic flow can be computed from image sequences. Therefore studying whether artificial systems, such as robots, can use optic flow for similar purposes is of particular interest. Experiments are reviewed that suggest the possible use of optic flow for the navigation of a robot moving in indoor and outdoor environments. The optic flow is used to detect and localise obstacles in indoor scenes, such as corridors, offices, and laboratories. These routines are based on the computation of a reduced optic flow. The robot is usually able to avoid large obstacles such as a chair or a person. The avoidance performances of the proposed algorithm critically depend on the optomotor reaction of the robot. The optic flow can be used to understand the ego-motion in outdoor scenes, that is, to obtain information on the absolute velocity of the moving vehicle and to detect the presence of other moving objects. A critical step is the correction of the optic flow for shocks and vibrations present during image acquisition. The results obtained suggest that optic flow can be successfully used by biological and artificial systems to control their navigation. Moreover, both systems require fast and accurate optomotor reactions and need to compensate for the instability of the viewed world. PMID:7617428

  18. Station Explorer X-Ray Timing and Navigation (SEXTANT) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Because of their predictable pulsations, pulsars are highly reliable celestial clocks that can provide the same high-precision timing as the atomic clock signals...

  19. Spatial Database Modeling for Indoor Navigation Systems

    Science.gov (United States)

    Gotlib, Dariusz; Gnat, Miłosz

    2013-12-01

    For many years, cartographers are involved in designing GIS and navigation systems. Most GIS applications use the outdoor data. Increasingly, similar applications are used inside buildings. Therefore it is important to find the proper model of indoor spatial database. The development of indoor navigation systems should utilize advanced teleinformation, geoinformatics, geodetic and cartographical knowledge. The authors present the fundamental requirements for the indoor data model for navigation purposes. Presenting some of the solutions adopted in the world they emphasize that navigation applications require specific data to present the navigation routes in the right way. There is presented original solution for indoor data model created by authors on the basis of BISDM model. Its purpose is to expand the opportunities for use in indoor navigation.

  20. Autonomous Robot Navigation based on Visual Landmarks

    DEFF Research Database (Denmark)

    Livatino, Salvatore

    2005-01-01

    autonomous navigation and self-localization using automatically selected landmarks. The thesis investigates autonomous robot navigation and proposes a new method which benefits from the potential of the visual sensor to provide accuracy and reliability to the navigation process while relying on naturally...... update of the estimated robot position while the robot is moving. In order to make the system autonomous, both acquisition and observation of landmarks have to be carried out automatically. The thesis consequently proposes a method for learning and navigation of a working environment and it explores......The use of landmarks for robot navigation is a popular alternative to having a geometrical model of the environment through which to navigate and monitor self-localization. If the landmarks are defined as special visual structures already in the environment then we have the possibility of fully...

  1. INS/CNS/GNSS integrated navigation technology

    CERN Document Server

    Quan, Wei; Gong, Xiaolin; Fang, Jiancheng

    2015-01-01

    This book not only introduces the principles of INS, CNS and GNSS, the related filters and semi-physical simulation, but also systematically discusses the key technologies needed for integrated navigations of INS/GNSS, INS/CNS, and INS/CNS/GNSS, respectively. INS/CNS/GNSS integrated navigation technology has established itself as an effective tool for precise positioning navigation, which can make full use of the complementary characteristics of different navigation sub-systems and greatly improve the accuracy and reliability of the integrated navigation system. The book offers a valuable reference guide for graduate students, engineers and researchers in the fields of navigation and its control. Dr. Wei Quan, Dr. Jianli Li, Dr. Xiaolin Gong and Dr. Jiancheng Fang are all researchers at the Beijing University of Aeronautics and Astronautics.

  2. Indoor inertial waypoint navigation for the blind.

    Science.gov (United States)

    Riehle, Timothy H; Anderson, Shane M; Lichter, Patrick A; Whalen, William E; Giudice, Nicholas A

    2013-01-01

    Indoor navigation technology is needed to support seamless mobility for the visually impaired. This paper describes the construction and evaluation of an inertial dead reckoning navigation system that provides real-time auditory guidance along mapped routes. Inertial dead reckoning is a navigation technique coupling step counting together with heading estimation to compute changes in position at each step. The research described here outlines the development and evaluation of a novel navigation system that utilizes information from the mapped route to limit the problematic error accumulation inherent in traditional dead reckoning approaches. The prototype system consists of a wireless inertial sensor unit, placed at the users' hip, which streams readings to a smartphone processing a navigation algorithm. Pilot human trials were conducted assessing system efficacy by studying route-following performance with blind and sighted subjects using the navigation system with real-time guidance, versus offline verbal directions. PMID:24110904

  3. [Laser navigation guided cleft lip repair].

    Science.gov (United States)

    Bing, Shi

    2016-06-01

    A new method using the ideal mid-facial line as the navigating reference was introduced to improve the outcome of cleft lip repair. Using the verticle coordinate crossing the middle point of the intercanthus line, surgeons could observe and correct the distortion of the fine structures in labial-nasal area. This laser projecting mid-facial-line navigation was repeatable, while not interfere the operating. In conclusion, generalizing laser navigation is a valuable supplementary for cleft lip repair. PMID:27526442

  4. Konzeption und Implementierung eines Quellcode-Navigators

    OpenAIRE

    Lu, Leiqin

    2004-01-01

    The Bauhaus project supports program understanding on both architectural level and source code level, which requires a graphical user interface tool for source code navigation. In this thesis a source code navigator is designed and implemented as part of the Bauhaus toolkit. The source code navigator cooperates with other tools in the Bauhaus toolkit. In particular, it is fully integrated with Gravis, the tool for architectural view, to provide an integrated environment for program unders...

  5. Global navigation satellite systems and their applications

    CERN Document Server

    Madry, Scott

    2015-01-01

    Dr. Madry, one of the world's leading experts in the field, provides in a condensed form a quick yet comprehensive overview of satellite navigation. This book concisely addresses the latest technology, the applications, the regulatory issues, and the strategic implications of satellite navigation systems. This assesses the strengths and weaknesses of satellite navigation networks and review of all the various national systems now being deployed and the motivation behind the proliferation of these systems.

  6. Research on integrated navigation method for AUV

    Institute of Scientific and Technical Information of China (English)

    GUO Zhen; SUN Feng

    2005-01-01

    The principles of the SINS/DVL integrated navigation system are introduced, and the compass status accuracy is compared. When the heading is changed, the dead reckoning algorithm using the heading information of the SINS (Strapdown inertial navigation systems) and DVL (doppler velocity log) is adopted to substitute the SINS/DVL integrated system. The simulation results show that the method can improve the accuracy of integrated navigation system when AUV (autonomous underwater vehicle) is in motion.

  7. Memory consolidation of landmarks in good navigators.

    Science.gov (United States)

    Janzen, Gabriele; Jansen, Clemens; van Turennout, Miranda

    2008-01-01

    Landmarks play an important role in successful navigation. To successfully find your way around an environment, navigationally relevant information needs to be stored and become available at later moments in time. Evidence from functional magnetic resonance imaging (fMRI) studies shows that the human parahippocampal gyrus encodes the navigational relevance of landmarks. In the present event-related fMRI experiment, we investigated memory consolidation of navigationally relevant landmarks in the medial temporal lobe after route learning. Sixteen right-handed volunteers viewed two film sequences through a virtual museum with objects placed at locations relevant (decision points) or irrelevant (nondecision points) for navigation. To investigate consolidation effects, one film sequence was seen in the evening before scanning, the other one was seen the following morning, directly before scanning. Event-related fMRI data were acquired during an object recognition task. Participants decided whether they had seen the objects in the previously shown films. After scanning, participants answered standardized questions about their navigational skills, and were divided into groups of good and bad navigators, based on their scores. An effect of memory consolidation was obtained in the hippocampus: Objects that were seen the evening before scanning (remote objects) elicited more activity than objects seen directly before scanning (recent objects). This increase in activity in bilateral hippocampus for remote objects was observed in good navigators only. In addition, a spatial-specific effect of memory consolidation for navigationally relevant objects was observed in the parahippocampal gyrus. Remote decision point objects induced increased activity as compared with recent decision point objects, again in good navigators only. The results provide initial evidence for a connection between memory consolidation and navigational ability that can provide a basis for successful

  8. Robotics_MobileRobot Navigation Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Robots and rovers exploring planets need to autonomously navigate to specified locations. Advanced Scientific Concepts, Inc. (ASC) and the University of Minnesota...

  9. Lunar Autonomous Automatic Surface Navigation System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — To address the NASA GRC Laboratory need for navigation capabilities to provide location awareness, precision position fixing, best heading, and traverse path...

  10. Navigation and Ancillary Information Facility's SPICE

    Data.gov (United States)

    National Aeronautics and Space Administration — The Navigation and Ancillary Information Facility (NAIF), acting under the directions of NASA's Planetary Science Division, has built an information system named...

  11. Hybrid Guidance System for Relative Navigation Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Future NASA architectures and missions will involve many distributed platforms that must work together. This in turn requires guidance, navigation and control...

  12. Autonomous integrated navigation method based on the strapdown inertial navigation system and Lidar

    Science.gov (United States)

    Zhang, Xiaoyue; Lin, Zhili; Zhang, Chunxi

    2014-07-01

    An integrated navigation method based on the strapdown inertial navigation system (SINS) and Doppler Lidar was presented and its validity is demonstrated by practical experiments. A very effective and independent integrated navigation mode is realized that both an inertial navigation system (INS) and Lidar are not interfered with or screened by electromagnetic waves. In our work, the SINS error model was first introduced, and the velocity error model was transformed into body reference coordinates. Then the expression for measurement model of SINS/Lidar integrated navigation was deduced under Lidar reference coordinates. For application of land or vehicle navigation, the expression for the measurement model was simplified, and observation analysis was carried out. Finally, numerical simulation and vehicle test results were carried out to validate the availability and utility of the proposed SINS/Lidar integrated navigation method for land navigation.

  13. Autonomous navigation system and method

    Science.gov (United States)

    Bruemmer, David J. [Idaho Falls, ID; Few, Douglas A. [Idaho Falls, ID

    2009-09-08

    A robot platform includes perceptors, locomotors, and a system controller, which executes instructions for autonomously navigating a robot. The instructions repeat, on each iteration through an event timing loop, the acts of defining an event horizon based on the robot's current velocity, detecting a range to obstacles around the robot, testing for an event horizon intrusion by determining if any range to the obstacles is within the event horizon, and adjusting rotational and translational velocity of the robot accordingly. If the event horizon intrusion occurs, rotational velocity is modified by a proportion of the current rotational velocity reduced by a proportion of the range to the nearest obstacle and translational velocity is modified by a proportion of the range to the nearest obstacle. If no event horizon intrusion occurs, translational velocity is set as a ratio of a speed factor relative to a maximum speed.

  14. Chemical compass for bird navigation

    DEFF Research Database (Denmark)

    Solov'yov, Ilia; Hore, Peter J.; Ritz, Thorsten;

    2014-01-01

    Migratory birds travel spectacular distances each year, navigating and orienting by a variety of means, most of which are poorly understood. Among them is a remarkable ability to perceive the intensity and direction of the Earth's magnetic field. Biologically credible mechanisms for the detection...... other relies on the quantum spin dynamics of transient photoinduced radical pairs. Originally suggested by Schulten in 1978 as the basis of the avian magnetic compass sensor, this mechanism gained support from the subsequent observation that the compass is light-dependent. The radical pair hypothesis...... began to attract increased interest following the proposal in 2000 that free radical chemistry could occur in the bird's retina initiated by photoexcitation of cryptochrome, a specialized photoreceptor protein. In the present paper we review the important physical and chemical constraints on a possible...

  15. TARGET RELATIVE NAVIGATION PERFORMANCE RESULTS FROM SINPLEX: A MINIATURIZED NAVIGATION SYSTEM

    OpenAIRE

    Steffes, Stephen; Theil, Stephan; Dumke, Michael; Heise, David; Krüger, Hans; Sagliano, Marco; Samaan, Malak; Oosterling, Han; Boslooper, Erik; Duivenvoorde, Tom; Schulte, Jan; Söderholm, S.; Skaborn, Daniel; Yanson, Yuriy; Esposito, Marco

    2014-01-01

    The goal of the SINPLEX project is to develop an innovative solution to significantly reduce the mass of the navigation subsystem for exploration missions which include landing and/or rendezvous and capture phases. The system mass is reduced by functionally integrating the navigation sensors, using micro- and nanotechnology to miniaturize electronics and fusing the sensor data within a navigation filter to improve navigation performance. A breadboard system was built and includes ...

  16. The Discovery of the Regular Movements of Celestial Bodies and the Development of Monotheism in the Ancient Near East

    Science.gov (United States)

    Lanfranchi, G. B.

    2011-06-01

    For Ancient Mesopotamians, astronomical phenomena were signs signifying the gods' judgment on human behaviour. Mesopotamian scholars studied celestial phenomena for understanding the gods' will, and strongly developed astrology. From the 8th to the 6th century BC Assyrian and Babylonian astronomers achieved the ability to predict solar and lunar eclipses, and the planets' movements through mathematical calculations. Predictability of astral phenomena solicited the awareness that they are all regular, and that the universe is governed by an eternal, immutable order fixed at its very beginning. This finally favoured the idea that the cosmic order depended on the will of one god only, displacing polytheism in favour of monotheism; and astrology lost its religious importance as a mean to know the divine will.

  17. Zero initial partial derivatives of satellite orbits with respect to force parameters violate the physics of motion of celestial bodies

    Institute of Scientific and Technical Information of China (English)

    XU PeiLiang

    2009-01-01

    Satellite orbits have been routinely used to produce models of the Earth's gravity field. In connection with such productions, the partial derivatives of a satellite orbit with respect to the force parameters to be determined, namely, the unknown harmonic coefficients of the gravitational model, have been first computed by setting the initial values of partial derivatives to zero. In this note, we first design some simple mathematical examples to show that setting the initial values of partial derivatives to zero is generally erroneous mathematically. We then prove that it is prohibited physically. In other words, set-ting the initial values of partial derivatives to zero violates the physics of motion of celestial bodies.

  18. Zero initial partial derivatives of satellite orbits with respect to force parameters violate the physics of motion of celestial bodies

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Satellite orbits have been routinely used to produce models of the Earth’s gravity field. In connection with such productions, the partial derivatives of a satellite orbit with respect to the force parameters to be determined, namely, the unknown harmonic coefficients of the gravitational model, have been first computed by setting the initial values of partial derivatives to zero. In this note, we first design some simple mathematical examples to show that setting the initial values of partial derivatives to zero is generally erroneous mathematically. We then prove that it is prohibited physically. In other words, set-ting the initial values of partial derivatives to zero violates the physics of motion of celestial bodies.

  19. Waypoint navigation with a vibrotactile waist belt

    NARCIS (Netherlands)

    Erp, J.B.F. van; Veen, H.A.H.C. van; Jansen, C.; Dobbins, T.

    2005-01-01

    Presenting waypoint navigation on a visual display is not suited for all situations. The present experiments investigate if it is feasible to present the navigation information on a tactile display. Important design issue of the display is how direction and distance information must be coded. Import

  20. Blavigator: a navigation aid for blind persons

    OpenAIRE

    José, João; MORENO, M; Pinilla-Dutoit, J.; Rodrigues, J. M. F.; du Buf, J. M. H.

    2012-01-01

    Blavigator (blind navigator) is a vision aid for blind and visuaIIy impaired persons. It supports local navigation by detecting waIkable paths in the immediate vicinity of the user. It guides the user for centering on the path.

  1. Rosetta Star Tracker and Navigation Camera

    DEFF Research Database (Denmark)

    Thuesen, Gøsta

    1998-01-01

    Proposal in response to the Invitation to Tender (ITT) issued by Matra Marconi Space (MSS) for the procurement of the ROSETTA Star Tracker and Navigation Camera.......Proposal in response to the Invitation to Tender (ITT) issued by Matra Marconi Space (MSS) for the procurement of the ROSETTA Star Tracker and Navigation Camera....

  2. Understanding the Social Navigation User Experience

    Science.gov (United States)

    Goecks, Jeremy

    2009-01-01

    A social navigation system collects data from its users--its community--about what they are doing, their opinions, and their decisions, aggregates this data, and provides the aggregated data--community data--back to individuals so that they can use it to guide behavior and decisions. Social navigation systems empower users with the ability to…

  3. Validation of principles for tactile navigation displays

    NARCIS (Netherlands)

    Erp, J.B.F. van; Werkhoven, P.J.

    2006-01-01

    Access to navigation information rapidly becomes standard in many situations, for example through GPS receivers and collision avoidance systems in cars. However, perceiving and processing the information may result in overloading the userÆs visual sense and cognitive resources. Intuitive navigation

  4. Evolved Navigation Theory and Horizontal Visual Illusions

    Science.gov (United States)

    Jackson, Russell E.; Willey, Chela R.

    2011-01-01

    Environmental perception is prerequisite to most vertebrate behavior and its modern investigation initiated the founding of experimental psychology. Navigation costs may affect environmental perception, such as overestimating distances while encumbered (Solomon, 1949). However, little is known about how this occurs in real-world navigation or how…

  5. Center of Mass of Two or More Celestial Bodies as a Basis of Comets and «Black Holes» Mechanism

    OpenAIRE

    Eugeny F. Orlov

    2012-01-01

    The article considers the questions, arising during rendezvous of two celestial bodies with equal mass, one of which is the Earth and the consequences of such rendezvous to modern civilization, suggests the idea of centers of galaxies mass with anomalously large values of the gravitational fields, which allows to divide them into two types – material filled and hollow.

  6. Center of Mass of Two or More Celestial Bodies as a Basis of Comets and «Black Holes» Mechanism

    Directory of Open Access Journals (Sweden)

    Eugeny F. Orlov

    2012-04-01

    Full Text Available The article considers the questions, arising during rendezvous of two celestial bodies with equal mass, one of which is the Earth and the consequences of such rendezvous to modern civilization, suggests the idea of centers of galaxies mass with anomalously large values of the gravitational fields, which allows to divide them into two types – material filled and hollow.

  7. Enhancing Navigation on Wikipedia with Social Tags

    CERN Document Server

    Zubiaga, Arkaitz

    2012-01-01

    Social tagging has become an interesting approach to improve search and navigation over the actual Web, since it aggregates the tags added by different users to the same resource in a collaborative way. This way, it results in a list of weighted tags describing its resource. Combined to a classical taxonomic classification system such as that by Wikipedia, social tags can enhance document navigation and search. On the one hand, social tags suggest alternative navigation ways, including pivot-browsing, popularity-driven navigation, and filtering. On the other hand, it provides new metadata, sometimes uncovered by documents' content, that can substantially improve document search. In this work, the inclusion of an interface to add user-defined tags describing Wikipedia articles is proposed, as a way to improve article navigation and retrieval. As a result, a prototype on applying tags over Wikipedia is proposed in order to evaluate its effectiveness.

  8. GPS-based navigation for space applications

    Science.gov (United States)

    Champetier, C.; Duhamel, T.; Frezet, M.

    1995-03-01

    We present in this paper a survey of the applications of the GPS (global positioning system) system for spacecraft navigation. The use of the GPS techniques for space missions is a striking example of dual-use of military technology; it can bring vast improvements in performances and, in some cases, for a reduced cost. We only deal in this paper with the functional aspects and performances of GPS uses without addressing the issues of hardware implementation where current developments are leading to an increased miniaturization of the GPS receiver hardware. We start this paper with a general overview of the GPS system and its various uses for space missions. We then focus on four areas where MATRA MARCONI Space has conducted detailed analyses of performances: autonomous navigation for geostationary spacecraft, relative navigation for space rendezvous, differential navigation for landing vehicles, absolute navigation for launchers and reentry vehicles.

  9. Navigation aided surgery for facial fractures

    International Nuclear Information System (INIS)

    A navigation system that has been developed in neurosurgery has recently been applied in the maxillofacial region. We introduced a navigation system (Stealth Station, Medtronic) in the maxillofacial region. As preoperative preparation, CT scanning was performed with a slice of 1 mm. Navigation aided surgery was performed in 11 patients with facial fractures between April 2005 and July 2006. Navigation aided reduction of the bone segment was performed by comparing with the sound site on the screen. Facial symmetry was recovered in 10 of 11 cases. Facial asymmetry in 1 case (midfacial multiple fractures) remained, because the system did not work after the surgeon contacted the reference frame during the operation. The navigation system is useful for repairing facial fractures, especially for verifying facial symmetry. (author)

  10. Risk management model of winter navigation operations.

    Science.gov (United States)

    Valdez Banda, Osiris A; Goerlandt, Floris; Kuzmin, Vladimir; Kujala, Pentti; Montewka, Jakub

    2016-07-15

    The wintertime maritime traffic operations in the Gulf of Finland are managed through the Finnish-Swedish Winter Navigation System. This establishes the requirements and limitations for the vessels navigating when ice covers this area. During winter navigation in the Gulf of Finland, the largest risk stems from accidental ship collisions which may also trigger oil spills. In this article, a model for managing the risk of winter navigation operations is presented. The model analyses the probability of oil spills derived from collisions involving oil tanker vessels and other vessel types. The model structure is based on the steps provided in the Formal Safety Assessment (FSA) by the International Maritime Organization (IMO) and adapted into a Bayesian Network model. The results indicate that ship independent navigation and convoys are the operations with higher probability of oil spills. Minor spills are most probable, while major oil spills found very unlikely but possible. PMID:27207023

  11. New bionic navigation algorithm based on the visual navigation mechanism of bees

    Science.gov (United States)

    Huang, Yufeng; Liu, Yi; Liu, Jianguo

    2015-04-01

    Through some research on visual navigation mechanisms of flying insects especially honeybees, a novel navigation algorithm integrating entropy flow with Kalman filter has been introduced in this paper. Concepts of entropy image and entropy flow are also introduced, which can characterize topographic features and measure changes of the image respectively. To characterize texture feature and spatial distribution of an image, a new concept of contrast entropy image has been presented in this paper. Applying the contrast entropy image to the navigation algorithm to test its' performance of navigation and comparing with simulation results of intensity entropy image, a conclusion that contrast entropy image performs better and more robust in navigation has been made.

  12. Venous catheterization with ultrasound navigation

    Energy Technology Data Exchange (ETDEWEB)

    Kasatkin, A. A., E-mail: ant-kasatkin@yandex.ru; Nigmatullina, A. R. [Izhevsk State Medical Academy, Kommunarov street, 281, Izhevsk, Russia, 426034 (Russian Federation); Urakov, A. L., E-mail: ant-kasatkin@yandex.ru [Institute of Mechanics Ural Branch of Russian Academy of Sciences, T.Baramzinoy street 34, Izhevsk, Russia, 426067, Izhevsk (Russian Federation); Izhevsk State Medical Academy, Kommunarov street, 281, Izhevsk, Russia, 426034 (Russian Federation)

    2015-11-17

    By ultrasound scanning it was determined that respiratory movements made by chest of healthy and sick person are accompanied by respiratory chest rise of internal jugular veins. During the exhalation of an individual diameter of his veins increases and during the breath it decreases down to the complete disappearing if their lumen. Change of the diameter of internal jugular veins in different phases can influence significantly the results of vein puncture and cauterization in patients. The purpose of this research is development of the method increasing the efficiency and safety of cannulation of internal jugular veins by the ultrasound visualization. We suggested the method of catheterization of internal jugular veins by the ultrasound navigation during the execution of which the puncture of venous wall by puncture needle and the following conduction of J-guide is carried out at the moment of patient’s exhalation. This method decreases the risk of complications development during catheterization of internal jugular vein due to exclusion of perforating wound of vein and subjacent tissues and anatomical structures.

  13. Inertial sensors for smartphones navigation.

    Science.gov (United States)

    Dabove, P; Ghinamo, G; Lingua, A M

    2015-01-01

    The advent of smartphones and tablets, means that we can constantly get information on our current geographical location. These devices include not only GPS/GNSS chipsets but also mass-market inertial platforms that can be used to plan activities, share locations on social networks, and also to perform positioning in indoor and outdoor scenarios. This paper shows the performance of smartphones and their inertial sensors in terms of gaining information about the user's current geographical locatio n considering an indoor navigation scenario. Tests were carried out to determine the accuracy and precision obtainable with internal and external sensors. In terms of the attitude and drift estimation with an updating interval equal to 1 s, 2D accuracies of about 15 cm were obtained with the images. Residual benefits were also obtained, however, for large intervals, e.g. 2 and 5 s, where the accuracies decreased to 50 cm and 2.2 m, respectively. PMID:26753121

  14. Venous catheterization with ultrasound navigation

    Science.gov (United States)

    Kasatkin, A. A.; Urakov, A. L.; Nigmatullina, A. R.

    2015-11-01

    By ultrasound scanning it was determined that respiratory movements made by chest of healthy and sick person are accompanied by respiratory chest rise of internal jugular veins. During the exhalation of an individual diameter of his veins increases and during the breath it decreases down to the complete disappearing if their lumen. Change of the diameter of internal jugular veins in different phases can influence significantly the results of vein puncture and cauterization in patients. The purpose of this research is development of the method increasing the efficiency and safety of cannulation of internal jugular veins by the ultrasound visualization. We suggested the method of catheterization of internal jugular veins by the ultrasound navigation during the execution of which the puncture of venous wall by puncture needle and the following conduction of J-guide is carried out at the moment of patient's exhalation. This method decreases the risk of complications development during catheterization of internal jugular vein due to exclusion of perforating wound of vein and subjacent tissues and anatomical structures.

  15. Space optical navigation techniques: an overview

    Science.gov (United States)

    Rebordão, J. M.

    2013-11-01

    Optical or vision-based navigation is an enabling technology for satellite autonomous navigation associated to different navigation approaches such as cruising, fly-by, terrain relative navigation, landing, rendezvous and docking between spacecrafts, rigidity of multi-satellite constellations. Since 2001, in many different ESA projects, the author and his team (at INETI and currently at FCUL) have been associated to most of the developments of the optical components of autonomous navigation, in cooperation with space primes or GNC subsystems suppliers. A unique experience related to seemingly simple photonic concepts associated to computational vision, photonic noises, camera tradeoffs and system concepts has emerged, and deserves a synthesis especially because some of these concepts are being implemented in the ESA Proba 3 mission and ESA is currently updating the technology in view of forthcoming planetary missions to Jupiter, Jupiter moons and asteroids. It is important to note that the US have already flown several missions relying on autonomous navigation and that NASA experience is at least one decade old. System approaches, sources of difficulty, some tradeoffs in both (and between) hardware and software, critical interface issues between the imaging and GNC (Guidance, Navigation and Control) subsystems, image processing techniques, utilization of apriori or to be estimated information, uncertainties, simulation of the imaging chain and non-cooperative environments will be addressed synthetically for both passive (optical) and active (lidar) systems.

  16. Nuclear burst detection information transfers system based on BD Navigation

    International Nuclear Information System (INIS)

    The article introduces the character of BD Navigation System.The feasibility of using BD Navigation System is analyzed. Nuclear explosion information transmission system based on BD Navigation System is designed and implemented. (authors)

  17. Navigated minimally invasive unicompartmental knee arthroplasty.

    Science.gov (United States)

    Jenny, Jean-Yves; Müller, Peter E; Weyer, R; John, Michael; Weber, Patrick; Ciobanu, Eugène; Schmitz, Andreas; Bacher, Thomas; Neumann, Wolfram; Jansson, Volkmar

    2006-10-01

    Unicompartmental knee arthroplasty (UKA) is an alternative procedure to high tibial osteotomy. This study assessed the procedure using computer navigation to improve implantation accuracy and presents early radiological results of a group of patients implanted with the univation UKA (B. Braun Aesculap, Tuttlingen, Germany) with navigation instrumentation and a minimally invasive approach. The authors concluded that navigated implantation of a UKA using a nonimage-based system improved radiologic accuracy implantation without significant inconvenience and minimal change in the conventional operating technique. PMID:17407935

  18. Navigational Use of Cassini Delta V Telemetry

    Science.gov (United States)

    Roth, Duane C.; Antreasian, Peter G.; Ardalan, Shadan M.; Criddle, Kevin E.; Goodson, Troy; Ionasescu, Rodica; Jones, Jeremy B.; Parcher, Daniel W.; Pelletier, Frederic J.; Thompson, Paul F.; Vaughan, Andrew T.

    2008-01-01

    Telemetry data are used to improve navigation of the Saturn orbiting Cassini spacecraft. Thrust induced delta V's are computed on-board the spacecraft, recorded in telemetry, and downlinked to Earth. This paper discusses how and why the Cassini Navigation team utilizes spacecraft delta V telemetry. Operational changes making this information attractive to the Navigation Team will be briefly discussed, as will spacecraft hardware and software algorithms responsible for the on-board computation. An analysis of past delta V telemetry, providing calibrations and accuracies that can be applied to the estimation of future delta V activity, is described.

  19. INTERACTION SPECIFICITY IN AIR NAVIGATION COMMUNICATION

    Directory of Open Access Journals (Sweden)

    Kateryna Povoroznyk

    2012-09-01

    Full Text Available  The article is about a problem of air navigation communication and the positive influence of interpersonal communication for air navigation specialists. The ability of organizing a dialogue with subject – subject relationship substantially increase professional interaction efficiency. As scientific surveys show a dialogue is not just the form of communication, but an organizing phenomenon that directly influences the quality of air navigation communication, but there is still a gap in the aviation English teaching technics, mainly due to lack of psycho – pedagogical knowledge concerning human factor peculiarities within dialogical relationship framework. The article highlights the possible ways of the problem solution.

  20. Navigating nuclear science: Enhancing analysis through visualization

    Energy Technology Data Exchange (ETDEWEB)

    Irwin, N.H.; Berkel, J. van; Johnson, D.K.; Wylie, B.N.

    1997-09-01

    Data visualization is an emerging technology with high potential for addressing the information overload problem. This project extends the data visualization work of the Navigating Science project by coupling it with more traditional information retrieval methods. A citation-derived landscape was augmented with documents using a text-based similarity measure to show viability of extension into datasets where citation lists do not exist. Landscapes, showing hills where clusters of similar documents occur, can be navigated, manipulated and queried in this environment. The capabilities of this tool provide users with an intuitive explore-by-navigation method not currently available in today`s retrieval systems.

  1. Integration of Omega and satellite navigation systems

    Science.gov (United States)

    Schlachta, Henry B.

    An extensive series of laboratory tests and flight trials has established that the hybrid Omega/VLF/GPS system effectively applies GPS to the enhancement of Omega with a cost-effective operator installation. The accuracy enhancement thus achieved also increases the reliability of navigation and furnishes aviation fuel savings superior to those of Omega, as a result of reduced flight-path wavering. The prospective GPS/GLONASS navigation system currently undergoing definition will be the first certifiable as a sole means on navigation; the Omega/VLF/GPS hybrid can serve as a transitional system.

  2. Mars Rover Local Navigation And Hazard Avoidance

    Science.gov (United States)

    Wilcox, B. H.; Gennery, D. B.; Mishkin, A. H.

    1989-03-01

    A Mars rover sample return mission has been proposed for the late 1990's. Due to the long speed-of-light delays between Earth and Mars, some autonomy on the rover is highly desirable. JPL has been conducting research in two possible modes of rover operation, Computer-Aided Remote Driving and Semiautonomous Navigation. A recently-completed research program used a half-scale testbed vehicle to explore several of the concepts in semiautonomous navigation. A new, full-scale vehicle with all computational and power resources on-board will be used in the coming year to demonstrate relatively fast semiautonomous navigation. The computational and power requirements for Mars rover local navigation and hazard avoidance are discussed.

  3. Analysis of Ares 1 Ascent Navigation Options

    Science.gov (United States)

    Norris, Lee; Tao, Yee-Chee; Hall, Robert; Chuang, Jason; Whorton, Mark

    2008-01-01

    The paper documents a collaborative analysis of ascent Navigation options for the Ares 1 launch vehicle by the NASA Marshall Space Flight Center (MSFC) and the C. S. Draper Laboratory. The objective of the work was the development of a Navigation concept and supporting requirements which meet the Ares 1 accuracy specification in a manner which is straightforward, reliable, and cost effective. Six primary Navigation architectures were considered. In each case analysis was performed to determine under what conditions the required accuracy at second stage cutoff could be achieved. Those architectures which met the accuracy requirements were then assessed in terms of cost, complexity, and reliability to determine a baseline Navigation approach and the primary supporting requirements.

  4. 5th China Satellite Navigation Conference

    CERN Document Server

    Jiao, Wenhai; Wu, Haitao; Lu, Mingquan

    2014-01-01

    China Satellite Navigation Conference (CSNC) 2014 Proceedings presents selected research papers from CSNC2014, held on 21-23 May in Nanjing, China. The theme of CSNC2014 is 'BDS Application: Innovation, Integration and Sharing'. These papers discuss the technologies and applications of the Global Navigation Satellite System (GNSS), and the latest progress made in the China BeiDou System (BDS) especially. They are divided into 9 topics to match the corresponding sessions in CSNC2014, which broadly covered key topics in GNSS. Readers can learn about the BDS and keep abreast of the latest advances in GNSS techniques and applications.  SUN Jiadong is the Chief Designer of the Compass/ BDS, and the Academician of Chinese Academy of Sciences (CAS); JIAO Wenhai is a researcher at China Satellite Navigation Office; WU Haitao is a professor at Navigation Headquarters, CAS; LU Mingquan is a professor at Department of Electronic Engineering of Tsinghua University.

  5. Indoor magnetic navigation for the blind.

    Science.gov (United States)

    Riehle, Timothy H; Anderson, Shane M; Lichter, Patrick A; Giudice, Nicholas A; Sheikh, Suneel I; Knuesel, Robert J; Kollmann, Daniel T; Hedin, Daniel S

    2012-01-01

    Indoor navigation technology is needed to support seamless mobility for the visually impaired. This paper describes the construction of and evaluation of a navigation system that infers the users' location using only magnetic sensing. It is well known that the environments within steel frame structures are subject to significant magnetic distortions. Many of these distortions are persistent and have sufficient strength and spatial characteristics to allow their use as the basis for a location technology. This paper describes the development and evaluation of a prototype magnetic navigation system consisting of a wireless magnetometer placed at the users' hip streaming magnetic readings to a smartphone processing location algorithms. Human trials were conducted to assess the efficacy of the system by studying route-following performance with blind and sighted subjects using the navigation system for real-time guidance. PMID:23366303

  6. Plenoptic Imager for Automated Surface Navigation Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Autonomous and semi-autonomous robotic systems require information about their surroundings in order to navigate properly. A video camera machine vision system can...

  7. NOAA Seamless Raster Navigational Charts (RNC)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NOAA Seamless Raster Chart Server provides a seamless collarless mosaic of the NOAA Raster Navigational Charts (RNC). The RNC are a collection of approximately...

  8. Observability analysis of Mars entry integrated navigation

    Science.gov (United States)

    Wang, Liansheng; Xia, Yuanqing

    2015-09-01

    This paper studies three schemes of Mars entry navigation: inertial measurement unit (IMU) based dead reckoning (DR), IMU/orbiter based integrated navigation, and IMU/orbiter/Mars surface beacon (MSB) based integrated navigation. We demonstrate through simulations that first scheme, IMU based DR, produces substantially large state estimation errors. Although these errors are reduced by adding two Mars orbiters, the system is only barely observable. However, by adding two MSBs in above configuration, the position and velocity estimation errors are reduced to the scope of 10 m and 0.5 m/s respectively and the navigation system becomes completely observable. Finally, the estimability of states is investigated; it is observed that velocity variables or velocity variables linear combinations can be estimated better than position variables.

  9. LEO AUTONOMOUS NAVIGATION BASED ON IMAGE MOTION

    Institute of Scientific and Technical Information of China (English)

    DUANFang; LIUJian-ye; YUFeng

    2005-01-01

    A method of LEO autonomous navigation is presented based on the nonlinear satellite velocity relative to the earth. The velocity is detected by a high-speed camera, with the attitude information detected by a star sensor. Compared with traditional autonomous navigation by landmark identification, the satellite velocity relarive to the earth is obtained by correlativity analysis of images. It does not need to recognize ground objects or views. Since it is not necessary to pre-store the database of ground marks, lots of memory space can be saved.The state and observation equations are constructed, and the filtering is processed by the Kalman filter. Simulation results show that the system has high autonomous navigation precision in LEO autonomous navigation.

  10. Navigation with a passive brain based interface

    NARCIS (Netherlands)

    Erp, J.B.F. van; Werkhoven, P.J.; Thurlings, M.E.; Brouwer, A.-M.

    2009-01-01

    In this paper, we describe a Brain Computer Interface (BCI) for navigation. The system is based on detecting brain signals that are elicited by tactile stimulation on the torso indicating the desired direction.

  11. Mars rover local navigation and hazard avoidance

    Science.gov (United States)

    Wilcox, B. H.; Gennery, D. B.; Mishkin, A. H.

    1989-01-01

    A Mars rover sample return mission has been proposed for the late 1990's. Due to the long speed-of-light delays between earth and Mars, some autonomy on the rover is highly desirable. JPL has been conducting research in two possible modes of rover operation, Computer-Aided Remote Driving and Semiautonomous Navigation. A recently-completed research program used a half-scale testbed vehicle to explore several of the concepts in semiautonomous navigation. A new, full-scale vehicle with all computational and power resources on-board will be used in the coming year to demonstrate relatively fast semiautonomous navigation. The computational and power requirements for Mars rover local navigation and hazard avoidance are discussed.

  12. Indoor Navigation Using an iPhone

    OpenAIRE

    Emilsson, André

    2010-01-01

    Indoor navigation could be used in many applications to enhance performance in its specific area. Anything from serious life critical tasks like aiding firefighters or coordinating military attacks to more simple every day use like finding a desired shop in a large supermarket could be considered. Smartphones of today introduce an interesting platform with capabilities like existing, more clumsy, indoor navigation systems. The iPhone 3GS is a powerful smartphone that lets the programmer use i...

  13. Inertial Navigation and Mapping for Autonomous Vehicles

    OpenAIRE

    Skoglund, Martin

    2014-01-01

    Navigation and mapping in unknown environments is an important building block for increased autonomy of unmanned vehicles, since external positioning systems can be susceptible to interference or simply being inaccessible. Navigation and mapping require signal processing of vehicle sensor data to estimate motion relative to the surrounding environment and to simultaneously estimate various properties of the surrounding environment. Physical models of sensors, vehicle motion and external influ...

  14. Electromagnetic tracking and steering for catheter navigation

    OpenAIRE

    O'Donoghue, Kilian

    2014-01-01

    This thesis explores the use of electromagnetics for both steering and tracking of medical instruments in minimally invasive surgeries. The end application is virtual navigation of the lung for biopsy of early stage cancer nodules. Navigation to the peripheral regions of the lung is difficult due to physical dimensions of the bronchi and current methods have low successes rates for accurate diagnosis. Firstly, the potential use of DC magnetic fields for the actuation of catheter devices with ...

  15. Precise laser gyroscope for autonomous inertial navigation

    International Nuclear Information System (INIS)

    Requirements to gyroscopes of strapdown inertial navigation systems for aircraft application are formulated. The construction of a ring helium – neon laser designed for autonomous navigation is described. The processes that determine the laser service life and the relation between the random error of the angular velocity measurement and the surface relief features of the cavity mirrors are analysed. The results of modelling one of the promising approaches to processing the laser gyroscope signals are presented. (laser gyroscopes)

  16. 19 CFR 4.98 - Navigation fees.

    Science.gov (United States)

    2010-04-01

    ... calculated in accordance with § 24.17(d) Customs Regulations (19 CFR 24.17(d)), and be based upon the amount... 19 Customs Duties 1 2010-04-01 2010-04-01 false Navigation fees. 4.98 Section 4.98 Customs Duties... VESSELS IN FOREIGN AND DOMESTIC TRADES General § 4.98 Navigation fees. (a)(1) The Customs Service...

  17. Applying AHP to Web Navigation Design

    OpenAIRE

    Su-Hua Wang; Che-Hung Lin

    2008-01-01

    Due to increasing popularity of the World Wide Web, web-based systems are widely used. Most corporate web sites try to enhance their usability by providing artistic web presentations. However, the design of web sites is not judged solely on an artistic basis. Two of the most important design criteria for web sites are access to web content and navigation architecture. This research proposes a platform for automatically evaluating the quality of web navigation architecture. Because of the hier...

  18. Sensory mechanisms of animal orientation and navigation

    OpenAIRE

    Muheim, R.; Boström, J.; Åkesson, S.; Liedvogel, M

    2014-01-01

    Although questions such as 'How do animals find their way, and how do they sense and process this information in the brain?' have been asked for centuries , the field of animal orientation and navigation has seen an immense leap forward in the past few decades. Moreover, our understanding has also expanded considerably regarding the molecular and physiological mechanisms of the different compasses and cues used by animals for orientation and navigation (Åkesson et al., Chapter 9, and Svensson...

  19. An integrated platform for inertial navigation systems

    Science.gov (United States)

    Dumitrascu, Ana; Tamas, Razvan D.; Caruntu, George; Bobirca, Daniel

    2015-02-01

    In this paper we propose a new configuration for an inertial navigation system (INS), type strap down, designed to be used onboard a ship. The system consists of an inertial navigation unit (IMU), using a 9-axis inertial sensor and pressure and temperature sensors, a GPS module, various interfaces for optimal communication and command, a microcontroller for data processing and computing and a power supply.

  20. VOR area navigation - Techniques and results

    Science.gov (United States)

    Ragsdale, W. A.

    1982-01-01

    Several methods for deriving position from VOR (without DME) have been developed and evaluated in this study. These methods permit navigation to arbitrary waypoints using either two VOR's or one VOR and a clock. These algorithms have been tested in computer simulations and in flight tests. The single VOR method appears to be the most practical and is a candidate for an automated light plane area navigation system, called VORNAV.

  1. Neurobiologically inspired mobile robot navigation and planning

    OpenAIRE

    Mathias Quoy

    2007-01-01

    After a short review of biologically inspired navigation architectures, mainly relying on modeling the hippocampal anatomy, or at least some of its functions, we present a navigation and planning model for mobile robots. This architecture is based on a model of the hippocampal and prefrontal interactions. In particular, the system relies on the definition of a new cell type “transition cells” that encompasses traditional “place cells”.

  2. Neurobiologically Inspired Mobile Robot Navigation and Planning

    OpenAIRE

    Cuperlier, Nicolas; Quoy, Mathias; Gaussier, Philippe

    2007-01-01

    After a short review of biologically inspired navigation architectures, mainly relying on modeling the hippocampal anatomy, or at least some of its functions, we present a navigation and planning model for mobile robots. This architecture is based on a model of the hippocampal and prefrontal interactions. In particular, the system relies on the definition of a new cell type “transition cells” that encompasses traditional “place cells”.

  3. Neurobiologically inspired mobile robot navigation and planning

    Directory of Open Access Journals (Sweden)

    Mathias Quoy

    2007-11-01

    Full Text Available After a short review of biologically inspired navigation architectures, mainly relying on modeling the hippocampal anatomy, or at least some of its functions, we present a navigation and planning model for mobile robots. This architecture is based on a model of the hippocampal and prefrontal interactions. In particular, the system relies on the definition of a new cell type “transition cells” that encompasses traditional “place cells”.

  4. A Real-Time Autonomous Navigation Architecture

    OpenAIRE

    Chen, Gang; Fraichard, Thierry; Martinez-Gomez, Luis

    2007-01-01

    This paper presents a novel navigation architecture for automated car-like vehicles in urban environments. Motion safety is a critical issue in such environments given that they are partially known and highly dynamic with moving objects (other vehicles, pedestrians...). The main feature of the navigation architecture proposed is its ability to make safe motion decisions in real-time, thus taking into account the harsh constraints imposed by the type of environments considered. The architectur...

  5. Autonomous navigation and sign detector learning

    OpenAIRE

    Ellis, Liam; Pugeault, Nicolas; Öfjäll, Kristoffer; Hedborg, Johan; Bowden, Richard; Felsberg, Michael

    2013-01-01

    This paper presents an autonomous robotic system that incorporates novel Computer Vision, Machine Learning and Data Mining algorithms in order to learn to navigate and discover important visual entities. This is achieved within a Learning from Demonstration (LfD) framework, where policies are derived from example state-to-action mappings. For autonomous navigation, a mapping is learnt from holistic image features (GIST) onto control parameters using Random Forest regression. Additionally, vis...

  6. Precise laser gyroscope for autonomous inertial navigation

    Energy Technology Data Exchange (ETDEWEB)

    Kuznetsov, A G; Molchanov, A V; Izmailov, E A [Joint Stock Company ' Moscow Institute of Electromechanics and Automatics' , Moscow (Russian Federation); Chirkin, M V [Ryazan State Radio Engineering University (Russian Federation)

    2015-01-31

    Requirements to gyroscopes of strapdown inertial navigation systems for aircraft application are formulated. The construction of a ring helium – neon laser designed for autonomous navigation is described. The processes that determine the laser service life and the relation between the random error of the angular velocity measurement and the surface relief features of the cavity mirrors are analysed. The results of modelling one of the promising approaches to processing the laser gyroscope signals are presented. (laser gyroscopes)

  7. Visual navigation for an autonomous mobile vehicle

    OpenAIRE

    Peterson, Kevin Robert

    1992-01-01

    Approved for public release; distribution is unlimited Image understanding for a mobile robotic vehicle is an important and complex task for ensuring safe navigation and extended autonomous operations. The goal of this work is to implement a working vision-based navigation control mechanism within a known environment onboard the autonomous mobile vehicle Yamabico-II. Although installing a working hardware system was not accomplished, the image processing, model description, pattern match...

  8. Effectiveness and Ergonomics of Integrated Navigation System

    OpenAIRE

    Vidan, Pero; Stanivuk, Tatjana; Bielić, Toni

    2012-01-01

    Ergonomics increases the efficiency of people and device interaction. Nowadays, modern navigation bridges are designed in accordance with the requirements of navigators, designers and shipowners, production costs etc. The bridge design, various layouts, instrument arrangements and their capacities etc. have not been fully regulated by the SOLAS convention. The Convention regulates manufacturers’ requirements which refer to accuracy, device sensitivity etc. However, factors that are important ...

  9. Mobility and Navigation among the Yucatec Maya

    OpenAIRE

    Cashdan, Elizabeth; Kramer, Karen L.; Davis, Helen E.; Padilla, Lace; Greaves, Russell D.

    2015-01-01

    Sex differences in range size and navigation are widely reported, with males traveling farther than females, being less spatially anxious, and in many studies navigating more effectively. One explanation holds that these differences are the result of sexual selection, with larger ranges conferring mating benefits on males, while another explanation focuses on greater parenting costs that large ranges impose on reproductive-aged females. We evaluated these arguments with data from a community ...

  10. Location Assurance and Privacy in GNSS Navigation

    OpenAIRE

    Chen, Xihui; Harpes, Carlo; Lenzini, Gabriele; Mauw, Sjouke; Pang, Jun

    2013-01-01

    The growing popularity of location-based services such as GNSS (Global Navigation Satellite System) navigation requires confidence in the reliability of the calculated locations. The exploration of a user’s location also gives rise to severe privacy concerns. Within an ESA (European Space Agency) funded project, we have developed a service that not only verifies the correctness of users’ locations but also enables users to control the accuracy of their revealed locations.

  11. Interactive learning of visual topological navigation

    OpenAIRE

    Filliat, David

    2008-01-01

    International audience We present a topological navigation system that is able to visually recognize the different rooms of an apartment and guide a robot between them. Specifically tailored for small entertainment robots, the system relies on vision only and learns its navigation capabilities incrementally by interacting with a user. This continuous learning strategy makes the system particularly adaptable to environmental lighting and structure modifications. From the computer vision poi...

  12. Target Relative Navigation Results from Hardware-in-the-Loop Tests Using the SINPLEX Navigation System

    OpenAIRE

    Steffes, Stephen; Dumke, Michael; Heise, David; Sagliano, Marco; Samaan, Malak; Theil, Stephan

    2014-01-01

    The goal of the SINPLEX project is to develop an innovative solution to significantly reduce the mass of the navigation subsystem for exploration missions which include landing and/or rendezvous and capture phases. The system mass is reduced while still maintaining good navigation performance as compared to a conventional modular system. This is done by functionally integrating the navigation sensors, using micro- and nanotechnology to miniaturize electronics and fusing the sen...

  13. Simulation-based validation of navigation filter software for a shallow water AUV navigation system (SANS)

    OpenAIRE

    Steven, Ruediger.

    1996-01-01

    Navigation filter software is currently being developed for an inertial navigation system without rotating gyros. This system shall replace the navigation system that is currently used in the Phoenix Autonomous Underwater Vehicle of the Naval Postgraduate School. The filter combines acceleration sensors, angular rate sensors, a water speed sensor, a magnetic compass and a GPS system. The harmonization of the sensors is performed by gain matrices. The filter code must be tested for correctness...

  14. The Mathematics of Navigating the Solar System

    Science.gov (United States)

    Hintz, Gerald

    2000-01-01

    In navigating spacecraft throughout the solar system, the space navigator relies on three academic disciplines - optimization, estimation, and control - that work on mathematical models of the real world. Thus, the navigator determines the flight path that will consume propellant and other resources in an efficient manner, determines where the craft is and predicts where it will go, and transfers it onto the optimal trajectory that meets operational and mission constraints. Mission requirements, for example, demand that observational measurements be made with sufficient precision that relativity must be modeled in collecting and fitting (the estimation process) the data, and propagating the trajectory. Thousands of parameters are now determined in near real-time to model the gravitational forces acting on a spacecraft in the vicinity of an irregularly shaped body. Completing these tasks requires mathematical models, analyses, and processing techniques. Newton, Gauss, Lambert, Legendre, and others are justly famous for their contributions to the mathematics of these tasks. More recently, graduate students participated in research to update the gravity model of the Saturnian system, including higher order gravity harmonics, tidal effects, and the influence of the rings. This investigation was conducted for the Cassini project to incorporate new trajectory modeling features in the navigation software. The resulting trajectory model will be used in navigating the 4-year tour of the Saturnian satellites. Also, undergraduate students are determining the ephemerides (locations versus time) of asteroids that will be used as reference objects in navigating the New Millennium's Deep Space 1 spacecraft autonomously.

  15. Sensor fusion for improved indoor navigation

    Science.gov (United States)

    Emilsson, Erika; Rydell, Joakim

    2012-09-01

    A reliable indoor positioning system providing high accuracy has the potential to increase the safety of first responders and military personnel significantly. To enable navigation in a broad range of environments and obtain more accurate and robust positioning results, we propose a multi-sensor fusion approach. We describe and evaluate a positioning system, based on sensor fusion between a foot-mounted inertial measurement unit (IMU) and a camera-based system for simultaneous localization and mapping (SLAM). The complete system provides accurate navigation in many relevant environments without depending on preinstalled infrastructure. The camera-based system uses both inertial measurements and visual data, thereby enabling navigation also in environments and scenarios where one of the sensors provides unreliable data during a few seconds. When sufficient light is available, the camera-based system generally provides good performance. The foot-mounted system provides accurate positioning when distinct steps can be detected, e.g., during walking and running, even in dark or smoke-filled environments. By combining the two systems, the integrated positioning system can be expected to enable accurate navigation in almost all kinds of environments and scenarios. In this paper we present results from initial tests, which show that the proposed sensor fusion improves the navigation solution considerably in scenarios where either the foot-mounted or camera-based system is unable to navigate on its own.

  16. NFC internal: an indoor navigation system.

    Science.gov (United States)

    Ozdenizci, Busra; Coskun, Vedat; Ok, Kerem

    2015-01-01

    Indoor navigation systems have recently become a popular research field due to the lack of GPS signals indoors. Several indoors navigation systems have already been proposed in order to eliminate deficiencies; however each of them has several technical and usability limitations. In this study, we propose NFC Internal, a Near Field Communication (NFC)-based indoor navigation system, which enables users to navigate through a building or a complex by enabling a simple location update, simply by touching NFC tags those are spread around and orient users to the destination. In this paper, we initially present the system requirements, give the design details and study the viability of NFC Internal with a prototype application and a case study. Moreover, we evaluate the performance of the system and compare it with existing indoor navigation systems. It is seen that NFC Internal has considerable advantages and significant contributions to existing indoor navigation systems in terms of security and privacy, cost, performance, robustness, complexity, user preference and commercial availability. PMID:25825976

  17. NFC Internal: An Indoor Navigation System

    Directory of Open Access Journals (Sweden)

    Busra Ozdenizci

    2015-03-01

    Full Text Available Indoor navigation systems have recently become a popular research field due to the lack of GPS signals indoors. Several indoors navigation systems have already been proposed in order to eliminate deficiencies; however each of them has several technical and usability limitations. In this study, we propose NFC Internal, a Near Field Communication (NFC-based indoor navigation system, which enables users to navigate through a building or a complex by enabling a simple location update, simply by touching NFC tags those are spread around and orient users to the destination. In this paper, we initially present the system requirements, give the design details and study the viability of NFC Internal with a prototype application and a case study. Moreover, we evaluate the performance of the system and compare it with existing indoor navigation systems. It is seen that NFC Internal has considerable advantages and significant contributions to existing indoor navigation systems in terms of security and privacy, cost, performance, robustness, complexity, user preference and commercial availability.

  18. LOFAR MSSS: detection of a low-frequency radio transient in 400 h of monitoring of the North Celestial Pole

    Science.gov (United States)

    Stewart, A. J.; Fender, R. P.; Broderick, J. W.; Hassall, T. E.; Muñoz-Darias, T.; Rowlinson, A.; Swinbank, J. D.; Staley, T. D.; Molenaar, G. J.; Scheers, B.; Grobler, T. L.; Pietka, M.; Heald, G.; McKean, J. P.; Bell, M. E.; Bonafede, A.; Breton, R. P.; Carbone, D.; Cendes, Y.; Clarke, A. O.; Corbel, S.; de Gasperin, F.; Eislöffel, J.; Falcke, H.; Ferrari, C.; Grießmeier, J.-M.; Hardcastle, M. J.; Heesen, V.; Hessels, J. W. T.; Horneffer, A.; Iacobelli, M.; Jonker, P.; Karastergiou, A.; Kokotanekov, G.; Kondratiev, V. I.; Kuniyoshi, M.; Law, C. J.; van Leeuwen, J.; Markoff, S.; Miller-Jones, J. C. A.; Mulcahy, D.; Orru, E.; Pandey-Pommier, M.; Pratley, L.; Rol, E.; Röttgering, H. J. A.; Scaife, A. M. M.; Shulevski, A.; Sobey, C. A.; Stappers, B. W.; Tasse, C.; van der Horst, A. J.; van Velzen, S.; van Weeren, R. J.; Wijers, R. A. M. J.; Wijnands, R.; Wise, M.; Zarka, P.; Alexov, A.; Anderson, J.; Asgekar, A.; Avruch, I. M.; Bentum, M. J.; Bernardi, G.; Best, P.; Breitling, F.; Brüggen, M.; Butcher, H. R.; Ciardi, B.; Conway, J. E.; Corstanje, A.; de Geus, E.; Deller, A.; Duscha, S.; Frieswijk, W.; Garrett, M. A.; Gunst, A. W.; van Haarlem, M. P.; Hoeft, M.; Hörandel, J.; Juette, E.; Kuper, G.; Loose, M.; Maat, P.; McFadden, R.; McKay-Bukowski, D.; Moldon, J.; Munk, H.; Norden, M. J.; Paas, H.; Polatidis, A. G.; Schwarz, D.; Sluman, J.; Smirnov, O.; Steinmetz, M.; Thoudam, S.; Toribio, M. C.; Vermeulen, R.; Vocks, C.; Wijnholds, S. J.; Wucknitz, O.; Yatawatta, S.

    2016-03-01

    We present the results of a four-month campaign searching for low-frequency radio transients near the North Celestial Pole with the Low-Frequency Array (LOFAR), as part of the Multifrequency Snapshot Sky Survey (MSSS). The data were recorded between 2011 December and 2012 April and comprised 2149 11-min snapshots, each covering 175 deg2. We have found one convincing candidate astrophysical transient, with a duration of a few minutes and a flux density at 60 MHz of 15-25 Jy. The transient does not repeat and has no obvious optical or high-energy counterpart, as a result of which its nature is unclear. The detection of this event implies a transient rate at 60 MHz of 3.9^{+14.7}_{-3.7}× 10^{-4} d-1 deg-2, and a transient surface density of 1.5 × 10-5 deg-2, at a 7.9-Jy limiting flux density and ˜10-min time-scale. The campaign data were also searched for transients at a range of other time-scales, from 0.5 to 297 min, which allowed us to place a range of limits on transient rates at 60 MHz as a function of observation duration.

  19. The Atacama Cosmology Telescope: Physical Properties of Sunyaev-Zel'dovich Effect Clusters on the Celestial Equator

    CERN Document Server

    Menanteau, Felipe; Barrientos, L Felipe; Battaglia, Nicholas; Bond, J Richard; Crichton, Devin; Das, Sudeep; Devlin, Mark J; Dünner, Rolando; Gralla, Megan; Hajian, Amir; Hasselfield, Matthew; Hilton, Matt; Hincks, Adam D; Hughes, John P; Infante, Leopoldo; Kosowsky, Arthur; Marriage, Tobias A; Marsden, Danica; Moodley, Kavilan; Niemack, Michael D; Nolta, Michael R; Page, Lyman A; Partridge, Bruce; Reese, Erik D; Schmitt, Benjamin L; Sievers, Jon; Spergel, David N; Staggs, Suzanne T; Switzer, Eric; Wollack, Edward J

    2012-01-01

    We present the optical and X-ray properties of 68 galaxy clusters selected via the Sunyaev-Zel'dovich Effect at 148 GHz by the Atacama Cosmology Telescope (ACT). Our sample, from an area of 504 square degrees centered on the celestial equator, is divided into two regions. The main region uses 270 square degrees of the ACT survey that overlaps with the co-added ugriz imaging from the Sloan Digital Sky Survey (SDSS) over Stripe 82 plus additional near-infrared pointed observations with the Apache Point Observatory 3.5-meter telescope. We confirm a total of 49 clusters to z~1.3, of which 22 (all at z>0.55) are new discoveries. For the second region the regular-depth SDSS imaging allows us to confirm 19 more clusters up to z~0.7, of which 10 systems are new. We present the optical richness, photometric redshifts, and separation between the SZ position and the brightest cluster galaxy (BCG). We find no significant offset between the cluster SZ centroid and BCG location and a weak correlation between optical richne...

  20. LOFAR MSSS: Detection of a low-frequency radio transient in 400 hrs of monitoring of the North Celestial Pole

    CERN Document Server

    Stewart, A J; Broderick, J W; Hassall, T E; Muñoz-Darias, T; Rowlinson, A; Swinbank, J D; Staley, T D; Molenaar, G J; Scheers, B; Grobler, T L; Pietka, M; Heald, G; McKean, J P; Bell, M E; Bonafede, A; Breton, R P; Carbone, D; Cendes, Y; Clarke, A O; Corbel, S; de Gasperin, F; Eislöffel, J; Falcke, H; Ferrari, C; Grießmeier, J -M; Hardcastle, M J; Heesen, V; Hessels, J W T; Horneffer, A; Iacobelli, M; Jonker, P; Karastergiou, A; Kokotanekov, G; Kondratiev, V I; Kuniyoshi, M; Law, C J; van Leeuwen, J; Markoff, S; Miller-Jones, J C A; Mulcahy, D; Orru, E; Pandey-Pommier, M; Pratley, L; Rol, E; Röttgering, H J A; Scaife, A M M; Shulevski, A; Sobey, C A; Stappers, B W; Tasse, C; van der Horst, A J; van Velzen, S; van Weeren, R J; Wijers, R A M J; Wijnands, R; Wise, M; Zarka, P; Alexov, A; Anderson, J; Asgekar, A; Avruch, I M; Bentum, M J; Bernardi, G; Best, P; Breitling, F; Brüggen, M; Butcher, H R; Ciardi, B; Conway, J E; Corstanje, A; de Geus, E; Deller, A; Duscha, S; Frieswijk, W; Garrett, M A; Gunst, A W; van Haarlem, M P; Hoeft, M; Hörandel, J; Juette, E; Kuper, G; Loose, M; Maat, P; McFadden, R; McKay-Bukowski, D; Moldon, J; Munk, H; Norden, M J; Paas, H; Polatidis, A G; Schwarz, D; Sluman, J; Smirnov, O; Steinmetz, M; Thoudam, S; Toribio, M C; Vermeulen, R; Vocks, C; Wijnholds, S J; Wucknitz, O; Yatawatta, S

    2015-01-01

    We present the results of a four-month campaign searching for low-frequency radio transients near the North Celestial Pole with the Low-Frequency Array (LOFAR), as part of the Multifrequency Snapshot Sky Survey (MSSS). The data were recorded between 2011 December and 2012 April and comprised 2149 11-minute snapshots, each covering 175 deg^2. We have found one convincing candidate astrophysical transient, with a duration of a few minutes and a flux density at 60 MHz of 15-25 Jy. The transient does not repeat and has no obvious optical or high-energy counterpart, as a result of which its nature is unclear. The detection of this event implies a transient rate at 60 MHz of 3.9 (+14.7, -3.7) x 10^-4 day^-1 deg^-2, and a transient surface density of 1.5 x 10^-5 deg^-2, at a 7.9-Jy limiting flux density and ~10-minute time-scale. The campaign data were also searched for transients at a range of other time-scales, from 0.5 to 297 min, which allowed us to place a range of limits on transient rates at 60 MHz as a funct...

  1. Update on Pluto and Its 5 Moons Obeying the Quantization of Angular Momentum per Unit Mass Constraint of Quantum Celestial Mechanics

    OpenAIRE

    Potter F.

    2016-01-01

    In July, 2015, the New Horizons spacecraft passing by Pluto did not discover any more moons. Therefore, we know the Pluto system total angular momentum to within 2.4%, more accurately than any other system with more than two orbiting bodies. We there- fore update our previous analysis to determine whether a definitive test of the quantum celestial mechanics (QCM) angular momentum constraint can now be achieved.

  2. Update on Pluto and Its 5 Moons Obeying the Quantization of Angular Momentum per Unit Mass Constraint of Quantum Celestial Mechanics

    Directory of Open Access Journals (Sweden)

    Potter F.

    2016-01-01

    Full Text Available In July, 2015, the New Horizons spacecraft passing by Pluto did not discover any more moons. Therefore, we know the Pluto system total angular momentum to within 2.4%, more accurately than any other system with more than two orbiting bodies. We there- fore update our previous analysis to determine whether a definitive test of the quantum celestial mechanics (QCM angular momentum constraint can now be achieved.

  3. El recurso a la intercesión celestial en la hora de la muerte. Un estudio sobre los testamentos navarros.

    OpenAIRE

    García-de-la-Borbolla, Á. (Ángeles)

    2005-01-01

    El recurso a la intercesión celestial en la hora de la muerte fue una constante en la actitud del hombre medieval con respecto a la muerte. Las donaciones de la alta Edad Media y los testamentos de la baja Edad Media muestran el activo papel de los santos, mártires y confesores, la Virgen María, madre de Dios, y Cristo, para la salvación eterna de los fieles.

  4. 33 CFR 245.20 - Determination of hazard to navigation.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Determination of hazard to..., DEPARTMENT OF DEFENSE REMOVAL OF WRECKS AND OTHER OBSTRUCTIONS § 245.20 Determination of hazard to navigation... Coast Guard district to jointly determine whether the obstruction poses a hazard to navigation....

  5. Cognitive Costs of Navigation Aids in Hypermedia Learning

    Science.gov (United States)

    Waniek, Jacqueline; Ewald, Karolin

    2008-01-01

    This study examines the cognitive costs of navigation aids in a hypermedia learning task. In a 2(navigable vs. non-navigable) x 2(map vs. content list) experimental design cognitive requirements were measured by users' eye movement data. Additionally, data from users' navigation operations, knowledge acquisition, and subjective evaluation of the…

  6. 33 CFR 66.01-50 - Protection of private aids to navigation.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Protection of private aids to navigation. 66.01-50 Section 66.01-50 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY AIDS TO NAVIGATION PRIVATE AIDS TO NAVIGATION Aids to Navigation Other Than Federal or State §...

  7. Speech Recognition Technology Applied to Intelligent Mobile Navigation System

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The capability of human-computer interaction reflects the intelligent degree of mobile navigation system.The navigation data and functions of mobile navigation system are divided into system commands and non-system commands in this paper.And then a group of speech commands are Abstracted.This paper applies speech recognition technology to intelligent mobile navigation system to process speech commands and does some deep research on the integration of speech recognition technology with mobile navigation system.The navigation operation can be performed by speech commands,which makes human-computer interaction easy during navigation.Speech command interface of navigation system is implemented by Dutty ++ Software,which is based on speech recognition system -Via Voice of IBM.Through navigation experiments,navigation can be done almost without keyboard,which proved that human-computer interaction is very convenient by speech commands and the reliability is also higher.

  8. Intelligent navigation to improve obstetrical sonography.

    Science.gov (United States)

    Yeo, Lami; Romero, Roberto

    2016-04-01

    'Manual navigation' by the operator is the standard method used to obtain information from two-dimensional and volumetric sonography. Two-dimensional sonography is highly operator dependent and requires extensive training and expertise to assess fetal anatomy properly. Most of the sonographic examination time is devoted to acquisition of images, while 'retrieval' and display of diagnostic planes occurs rapidly (essentially instantaneously). In contrast, volumetric sonography has a rapid acquisition phase, but the retrieval and display of relevant diagnostic planes is often time-consuming, tedious and challenging. We propose the term 'intelligent navigation' to refer to a new method of interrogation of a volume dataset whereby identification and selection of key anatomical landmarks allow the system to: 1) generate a geometrical reconstruction of the organ of interest; and 2) automatically navigate, find, extract and display specific diagnostic planes. This is accomplished using operator-independent algorithms that are both predictable and adaptive. Virtual Intelligent Sonographer Assistance (VIS-Assistance®) is a tool that allows operator-independent sonographic navigation and exploration of the surrounding structures in previously identified diagnostic planes. The advantage of intelligent (over manual) navigation in volumetric sonography is the short time required for both acquisition and retrieval and display of diagnostic planes. Intelligent navigation technology automatically realigns the volume, and reorients and standardizes the anatomical position, so that the fetus and the diagnostic planes are consistently displayed in the same manner each time, regardless of the fetal position or the initial orientation. Automatic labeling of anatomical structures, subject orientation and each of the diagnostic planes is also possible. Intelligent navigation technology can operate on conventional computers, and is not dependent on specific ultrasound platforms or on the

  9. Integrated navigation method of a marine strapdown inertial navigation system using a star sensor

    International Nuclear Information System (INIS)

    This paper presents an integrated navigation method of the strapdown inertial navigation system (SINS) using a star sensor. According to the principle of SINS, its own navigation information contains an error that increases with time. Hence, the inertial attitude matrix from the star sensor is introduced as the reference information to correct the SINS increases error. For the integrated navigation method, the vehicle’s attitude can be obtained in two ways: one is calculated from SINS; the other, which we have called star sensor attitude, is obtained as the product between the SINS position and the inertial attitude matrix from the star sensor. Therefore, the SINS position error is introduced in the star sensor attitude error. Based on the characteristics of star sensor attitude error and the mathematical derivation, the SINS navigation errors can be obtained by the coupling calculation between the SINS attitude and the star sensor attitude. Unlike several current techniques, the navigation process of this method is non-radiating and invulnerable to jamming. The effectiveness of this approach was demonstrated by simulation and experimental study. The results show that this integrated navigation method can estimate the attitude error and the position error of SINS. Therefore, the SINS navigation accuracy is improved. (paper)

  10. Peculiarities of future air navigation system based on inertial navigation systems/global positioning system

    OpenAIRE

    Sineglazov, V. M.; National Aviation University,; Zakharin, F. M.; National Aviation University

    2014-01-01

    Using an inertial navigation system and Global Positioning System together is preferable to using any of them separately. Derived benefits depend on the level of combining information. Inertial navigation systems/Global Positioning System integration architectures are defined as separate, loosely and tightly coupled, deeply integrated configurations.

  11. Does Navigation Always Predict Performance? Effects of Navigation on Digital Reading Are Moderated by Comprehension Skills

    Science.gov (United States)

    Naumann, Johannes; Salmerón, Ladislao

    2016-01-01

    This study investigated interactive effects of navigation and offline comprehension skill on digital reading performance. As indicators of navigation, relevant page selection and irrelevant page selection were considered. In 533 Spanish high school students aged 11-17 positive effects of offline comprehension skill and relevant page selection on…

  12. Target relative navigation results from hardware-in-the-loop tests using the sinplex navigation system

    NARCIS (Netherlands)

    Steffes, S.; Dumke, M.; Heise, D.; Sagliano, M.; Samaan, M.; Theil, S.; Boslooper, E.C.; Oosterling, J.A.J.; Schulte, J.; Skaborn, D.; Söderholm, S.; Conticello, S.; Esposito, M.; Yanson, Y.; Monna, B.; Stelwagen, F.; Visee, R.

    2014-01-01

    The goal of the SINPLEX project is to develop an innovative solution to significantly reduce the mass of the navigation subsystem for exploration missions which include landing and/or rendezvous and capture phases. The system mass is reduced while still maintaining good navigation performance as com

  13. Integrated navigation method of a marine strapdown inertial navigation system using a star sensor

    Science.gov (United States)

    Wang, Qiuying; Diao, Ming; Gao, Wei; Zhu, Minghong; Xiao, Shu

    2015-11-01

    This paper presents an integrated navigation method of the strapdown inertial navigation system (SINS) using a star sensor. According to the principle of SINS, its own navigation information contains an error that increases with time. Hence, the inertial attitude matrix from the star sensor is introduced as the reference information to correct the SINS increases error. For the integrated navigation method, the vehicle’s attitude can be obtained in two ways: one is calculated from SINS; the other, which we have called star sensor attitude, is obtained as the product between the SINS position and the inertial attitude matrix from the star sensor. Therefore, the SINS position error is introduced in the star sensor attitude error. Based on the characteristics of star sensor attitude error and the mathematical derivation, the SINS navigation errors can be obtained by the coupling calculation between the SINS attitude and the star sensor attitude. Unlike several current techniques, the navigation process of this method is non-radiating and invulnerable to jamming. The effectiveness of this approach was demonstrated by simulation and experimental study. The results show that this integrated navigation method can estimate the attitude error and the position error of SINS. Therefore, the SINS navigation accuracy is improved.

  14. Navigation Architecture for a Space Mobile Network

    Science.gov (United States)

    Valdez, Jennifer E.; Ashman, Benjamin; Gramling, Cheryl; Heckler, Gregory W.; Carpenter, Russell

    2016-01-01

    The Tracking and Data Relay Satellite System (TDRSS) Augmentation Service for Satellites (TASS) is a proposed beacon service to provide a global, space based GPS augmentation service based on the NASA Global Differential GPS (GDGPS) System. The TASS signal will be tied to the GPS time system and usable as an additional ranging and Doppler radiometric source. Additionally, it will provide data vital to autonomous navigation in the near Earth regime, including space weather information, TDRS ephemerides, Earth Orientation Parameters (EOP), and forward commanding capability. TASS benefits include enhancing situational awareness, enabling increased autonomy, and providing near real-time command access for user platforms. As NASA Headquarters' Space Communication and Navigation Office (SCaN) begins to move away from a centralized network architecture and towards a Space Mobile Network (SMN) that allows for user initiated services, autonomous navigation will be a key part of such a system. This paper explores how a TASS beacon service enables the Space Mobile Networking paradigm, what a typical user platform would require, and provides an in-depth analysis of several navigation scenarios and operations concepts. This paper provides an overview of the TASS beacon and its role within the SMN and user community. Supporting navigation analysis is presented for two user mission scenarios: an Earth observing spacecraft in low earth orbit (LEO), and a highly elliptical spacecraft in a lunar resonance orbit. These diverse flight scenarios indicate the breadth of applicability of the TASS beacon for upcoming users within the current network architecture and in the SMN.

  15. Fuzzy Behavior Modulation with Threshold Activation for Autonomous Vehicle Navigation

    Science.gov (United States)

    Tunstel, Edward

    2000-01-01

    This paper describes fuzzy logic techniques used in a hierarchical behavior-based architecture for robot navigation. An architectural feature for threshold activation of fuzzy-behaviors is emphasized, which is potentially useful for tuning navigation performance in real world applications. The target application is autonomous local navigation of a small planetary rover. Threshold activation of low-level navigation behaviors is the primary focus. A preliminary assessment of its impact on local navigation performance is provided based on computer simulations.

  16. Indoor navigation using Bluetooth Low Energy (BLE) beacons

    OpenAIRE

    Herrera Vargas, Milan

    2016-01-01

    The popularity of indoor navigation has significantly increased during the last decade. Nowadays, many studies aim to develop new indoor navigation systems and improve the accuracy of the already existing ones. Unfortunately, no definitive method for indoor navigation has been approved yet, which is why this type of systems are not as accessible as those used for outdoor navigation. The purpose of this thesis is to introduce the concept of indoor navigation and demonstrate how common elec...

  17. From translation to navigation of different discourses

    DEFF Research Database (Denmark)

    Livonen, Mirja; Sonnenwald, Diane H.

    1998-01-01

    We propose a model of the search term selection process based on our empirical study of professional searchers during the pre-online stage of the search process. The model characterizes the selection of search terms as the navigation of different discourses. Discourse refers to the ways of talking...... and thinking about a certain topic; there often exists multiple, diverse discourses on the same topic. When selecting search terms, searchers appear to navigate a variety of discourses, i.e., they view the topic of a client's search request from the perspective of multiple discourse communities, and...... the searchers' own search experience. Data further suggest that searchers navigate these discourses dynamically and have preferences for certain discourses. Conceptualizing the selection of search terms as a meeting place of different discourses provides new insights into the complex nature of the...

  18. Mobile Navigation for Sport’s Pilots

    Directory of Open Access Journals (Sweden)

    Dušan Fister

    2013-06-01

    Full Text Available Today, global object-positioning is accomplished very precisely by GPS satellite technology. Access to this information is provided globally by widespread mobile devices with integrated GPS receivers from everywhere also from airplane. This paper presents a mobile device using GPS receiver to be used by mobile navigation for sports pilots. In fact, the mobile navigation is a mobile application running on Android. Thus, the current position of the airplane is indicated on the GoogleMaps and compared with the planned direction of the flight by the pilot. In addition, this mobile application could also serve flight instructors when tracking student pilots by first independent flights. The proposed solution has shown in practice to be the cheapest substitute for expensive professional navigation devices.

  19. Cloud Absorption Radiometer Autonomous Navigation System - CANS

    Science.gov (United States)

    Kahle, Duncan; Gatebe, Charles; McCune, Bill; Hellwig, Dustan

    2013-01-01

    CAR (cloud absorption radiometer) acquires spatial reference data from host aircraft navigation systems. This poses various problems during CAR data reduction, including navigation data format, accuracy of position data, accuracy of airframe inertial data, and navigation data rate. Incorporating its own navigation system, which included GPS (Global Positioning System), roll axis inertia and rates, and three axis acceleration, CANS expedites data reduction and increases the accuracy of the CAR end data product. CANS provides a self-contained navigation system for the CAR, using inertial reference and GPS positional information. The intent of the software application was to correct the sensor with respect to aircraft roll in real time based upon inputs from a precision navigation sensor. In addition, the navigation information (including GPS position), attitude data, and sensor position details are all streamed to a remote system for recording and later analysis. CANS comprises a commercially available inertial navigation system with integral GPS capability (Attitude Heading Reference System AHRS) integrated into the CAR support structure and data system. The unit is attached to the bottom of the tripod support structure. The related GPS antenna is located on the P-3 radome immediately above the CAR. The AHRS unit provides a RS-232 data stream containing global position and inertial attitude and velocity data to the CAR, which is recorded concurrently with the CAR data. This independence from aircraft navigation input provides for position and inertial state data that accounts for very small changes in aircraft attitude and position, sensed at the CAR location as opposed to aircraft state sensors typically installed close to the aircraft center of gravity. More accurate positional data enables quicker CAR data reduction with better resolution. The CANS software operates in two modes: initialization/calibration and operational. In the initialization/calibration mode

  20. Foot mounted inertial system for pedestrian navigation

    International Nuclear Information System (INIS)

    This paper discusses algorithmic concepts, design and testing of a system based on a low-cost MEMS-based inertial measurement unit (IMU) and high-sensitivity global positioning system (HSGPS) receivers for seamless personal navigation in a GPS signal degraded environment. The system developed here is mounted on a pedestrian shoe/foot and uses measurements based on the dynamics experienced by the inertial sensors on the user's foot. The IMU measurements are processed through a conventional inertial navigation system (INS) algorithm and are then integrated with HSGPS receiver measurements and dynamics derived constraint measurements using a tightly coupled integration strategy. The ability of INS to bridge the navigation solution is evaluated through field tests conducted indoors and in severely signal degraded forest environments. The specific focus is on evaluating system performance under challenging GPS conditions

  1. Active-imaging-based underwater navigation

    Science.gov (United States)

    Monnin, David; Schmitt, Gwenaël.; Fischer, Colin; Laurenzis, Martin; Christnacher, Frank

    2015-10-01

    Global navigation satellite systems (GNSS) are widely used for the localization and the navigation of unmanned and remotely operated vehicles (ROV). In contrast to ground or aerial vehicles, GNSS cannot be employed for autonomous underwater vehicles (AUV) without the use of a communication link to the water surface, since satellite signals cannot be received underwater. However, underwater autonomous navigation is still possible using self-localization methods which determines the relative location of an AUV with respect to a reference location using inertial measurement units (IMU), depth sensors and even sometimes radar or sonar imaging. As an alternative or a complementary solution to common underwater reckoning techniques, we present the first results of a feasibility study of an active-imaging-based localization method which uses a range-gated active-imaging system and can yield radiometric and odometric information even in turbid water.

  2. Benchmark Framework for Mobile Robots Navigation Algorithms

    Directory of Open Access Journals (Sweden)

    Nelson David Muñoz-Ceballos

    2014-01-01

    Full Text Available Despite the wide variety of studies and research on mobile robot systems, performance metrics are not often examined. This makes difficult to establish an objective comparison of achievements. In this paper, the navigation of an autonomous mobile robot is evaluated. Several metrics are described. These metrics, collectively, provide an indication of navigation quality, useful for comparing and analyzing navigation algorithms of mobile robots. This method is suggested as an educational tool, which allows the student to optimize the algorithms quality, relating to important aspectsof science, technology and engineering teaching, as energy consumption, optimization and design.

  3. Website Optimization through Mining User Navigational Pattern

    CERN Document Server

    Biswal, Biswajit

    2008-01-01

    With the World Wide Web's ubiquity increase and the rapid development of various online businesses, the complexity of web sites grow. The analysis of web user's navigational pattern within a web site can provide useful information for server performance enhancements, restructuring a website and direct marketing in e-commerce etc. In this paper, an algorithm is proposed for mining such navigation patterns. The key insight is that users access information of interest and follow a certain path while navigating a web site. If they don't find it, they would backtrack and choose among the alternate paths till they reach the destination. The point they backtrack is the Intermediate Reference Location. Identifying such Intermediate locations and destinations out of the pattern will be the main endeavor in the rest of this report.

  4. Indoor waypoint navigation via magnetic anomalies.

    Science.gov (United States)

    Riehle, Timothy H; Anderson, Shane M; Lichter, Patrick A; Condon, John P; Sheikh, Suneel I; Hedin, Daniel S

    2011-01-01

    A wide assortment of technologies have been proposed to construct indoor navigation services for the blind and vision impaired. Proximity-based systems and multilateration systems have been successfully demonstrated and employed. Despite the technical success of these technologies, broad adoption has been limited due to their significant infrastructure and maintenance costs. An alternative approach utilizing the indoor magnetic signatures inherent to steel-frame buildings solves the infrastructure cost problem; in effect the existing building is the location system infrastructure. Although magnetic indoor navigation does not require the installation of dedicated hardware, the dedication of resources to produce precise survey maps of magnetic anomalies represents a further barrier to adoption. In the present work an alternative leader-follower form of waypoint-navigation system has been developed that works without surveyed magnetic maps of a site. Instead the wayfarer's magnetometer readings are compared to a pre-recorded magnetic "leader" trace containing magnetic data collected along a route and annotated with waypoint information. The goal of the navigation system is to correlate the follower's magnetometer data with the leader's to trigger audio cues at precise points along the route, thus providing location-based guidance to the user. The system should also provide early indications of off-route conditions. As part of the research effort a smartphone based application was created to record and annotate leader traces with audio and numeric data at waypoints of interest, and algorithms were developed to determine (1) when the follower reaches a waypoint and (2) when the follower goes off-route. A navigation system utilizing this technology would enable a low-cost indoor navigation system capable of replaying audio annotations at precise locations along pre-recorded routes. PMID:22255538

  5. Computer navigation versus fluoroscopy-guided navigation for thoracic pedicle screw placement: a meta-analysis.

    Science.gov (United States)

    Meng, Xiao-Tong; Guan, Xiao-Fei; Zhang, Hai-Long; He, Shi-Sheng

    2016-07-01

    Although application of intraoperative computer navigation technique had been integrated into placement of pedicle screws (PSs) in thoracic fusion for years, its security and practicability remain controversial. The aim of this study is to evaluate the accuracy, the operative time consumption, the amount of intraoperative blood loss, time of pedicle insertion and the incidence of complications of thoracic pedicle screw placement in patients with thoracic diseases such as scoliosis and kyphosis. Pubmed, Web of Knowledge, and Google scholar were searched to identify comparative studies of thoracic pedicle screw placement between intraoperative computer navigation and fluoroscopy-guided navigation. Outcomes of malposition rate, operative time consumption, insertion time, intraoperative blood loss, and the incidence of complications are evaluated. Fourteen articles including 1723 patients and 9019 PSs were identified matching inclusion criteria. The malposition rate was lower (RR: 0.33, 95 % CI: 0.28-0.38, P < 0.01) in computer navigation group than that in fluoroscopy-guided navigation group; the operative time was significantly longer [weighted mean difference (WMD) = 23.66, 95 % CI: 14.74-32.57, P < 0.01] in computer navigation group than that in fluoroscopy-guided navigation group. The time of insertion was shorter (WMD = -1.88, 95 % CI: -2.25- -1.52, P < 0.01) in computer navigation group than that in fluoroscopy-guided navigation group. The incidence of complications was lower (RR = 0. 23, 95 % CI: 0.12-0.46, P < 0.01) in computer navigation group than that in the other group. The intraoperative blood loss was fewer (WMD = -167.49, 95 % CI: -266.39- -68.58, P < 0.01) in computer navigation group than that in the other. In conclusion, the meta-analysis of thoracic pedicle screw placement studies clearly demonstrated lower malposition rate, less intraoperative blood loss, and fewer complications when using computer

  6. Navigating Art Therapy: A Therapists Companion

    OpenAIRE

    Jones, Kevin

    2010-01-01

    From Art-making as a Defence to Works of Art, this anthology will help you navigate your way through the ever growing world of art therapy. Art therapy is used in an increasing range of settings and is influenced by a range of disciplines, including psychotherapy, social psychiatry, social work and education. Navigating Art Therapy is an essential companion for both seasoned art therapists and those new to the field as it offers a comprehensive guide to key terms and concepts. With con...

  7. Navigering och styrning av ett autonomt markfordon

    OpenAIRE

    Johansson, Sixten

    2006-01-01

    I detta examensarbete har ett system för navigering och styrning av ett autonomt fordon implementerats. Syftet med detta arbete är att vidareutveckla fordonet som ska användas vid utvärdering av banplaneringsalgoritmer och studier av andra autonomifunktioner. Med hjälp av olika sensormodeller och sensorkonfigurationer går det även att utvärdera olika strategier för navigering. Arbetet har utförts utgående från en given plattform där fordonet endast använder sig av enkla ultraljudssensorer sam...

  8. Quartz angular rate sensor for automotive navigation

    Energy Technology Data Exchange (ETDEWEB)

    Nozoe, Toshiyuki; Ichinose, Toshihiko; Kawasaki, Syusaku; Hatanaka, Masakazu; Kuroda, Keisuke [Matsushita Electronic Components Co. Ltd. (Japan); Yamamoto, Kohji; Ogata, Motoki; Takeno, Shoichi [Fukui Matsushita Electric Co. Ltd. (Japan); Ishihara, Minoru; Ishii, Tadashi; Umeki, Mitoshi [Nihonn Denpa Kogyo Co. Ltd. (Japan)

    1999-07-01

    Many of the recent automotive navigation systems are introducing an angular rate sensor that detect vehicle yaw in their system due to the advantage of higher accuracy, in addition to a conventional GPS (Global Positioning System) and vehicle speed signals. Though there are a couple of other methods to get a vehicle direction information, the angular rate sensor is the most suitable device as a gyro in accuracy and reliability point of view. Matsushita developed a new compact angular rate sensor using quartz crystal for automotive navigation systems. The sensor's operation is based upon Coriolis force imposed on a vibrating quartz tuning fork. (orig.)

  9. Navigation and control of an autonomous vehicle

    Energy Technology Data Exchange (ETDEWEB)

    Simon, A.; Soehnitz, I.; Becker, J.C.; Schumacher, W. [Technical Univ. Braunschweig (Germany). Inst. of Control Engineering

    2000-07-01

    This paper describes the fusion of sensor data for the navigation of an autonomous vehicle as well as two lateral control concepts to track the vehicle along a desired path. The fusion of navigation data is based on information provided by multiple object-detecting sensors. The object data is fused to increase the accuracy and to obtain the vehicle's state from the relative movement w.r.t. the objects. The presented lateral control methods are an LQG/H{sub 2}-design and an input-output linearizing algorithm. These control schemes were both implemented on a test vehicle. (orig.)

  10. Evolutionary strategy for achieving autonomous navigation

    Science.gov (United States)

    Gage, Douglas W.

    1999-01-01

    An approach is presented for the evolutionary development of supervised autonomous navigation capabilities for small 'backpackable' ground robots, in the context of a DARPA- sponsored program to provide robotic support to small units of dismounted warfighters. This development approach relies on the implementation of a baseline visual serving navigation capability, including tools to support operator oversight and override, which is then enhanced with semantically referenced commands and a mission scripting structure. As current and future machine perception techniques are able to automatically designate visual serving goal points, this approach should provide a natural evolutionary pathway to higher levels of autonomous operation and reduced requirements for operator intervention.

  11. Navigation: Bat orientation using Earth's magnetic field

    DEFF Research Database (Denmark)

    Holland, Richard A.; Thorup, Kasper; Vonhof, Maarten J.;

    2006-01-01

    Bats famously orientate at night by echolocation 1 , but this works over only a short range, and little is known about how they navigate over longer distances 2 . Here we show that the homing behaviour of Eptesicus fuscus, known as the big brown bat, can be altered by artificially shifting the...... Earth's magnetic field, indicating that these bats rely on a magnetic compass to return to their home roost. This finding adds to the impressive array of sensory abilities possessed by this animal for navigation in the dark....

  12. Diffusive chaos in navigation satellites orbits

    CERN Document Server

    Daquin, J; Tsiganis, K

    2016-01-01

    The navigation satellite constellations in medium-Earth orbit exist in a background of third-body secular resonances stemming from the perturbing gravitational effects of the Moon and the Sun. The resulting chaotic motions, emanating from the overlapping of neighboring resonant harmonics, induce especially strong perturbations on the orbital eccentricity, which can be transported to large values, thereby increasing the collision risk to the constellations and possibly leading to a proliferation of space debris. We show here that this transport is of a diffusive nature and we present representative diffusion maps that are useful in obtaining a global comprehension of the dynamical structure of the navigation satellite orbits.

  13. Neural encoding of objects relevant for navigation and resting state correlations with navigational ability.

    Science.gov (United States)

    Wegman, Joost; Janzen, Gabriele

    2011-12-01

    Objects along a route can help us to successfully navigate through our surroundings. Previous neuroimaging research has shown that the parahippocampal gyrus (PHG) distinguishes between objects that were previously encountered at navigationally relevant locations (decision points) and irrelevant locations (nondecision points) during simple object recognition. This study aimed at unraveling how this neural marking of objects relevant for navigation is established during learning and postlearning rest. Twenty-four participants were scanned using fMRI while they were viewing a route through a virtual environment. Eye movements were measured, and brain responses were time-locked to viewing each object. The PHG showed increased responses to decision point objects compared with nondecision point objects during route learning. We compared functional connectivity between the PHG and the rest of the brain in a resting state scan postlearning with such a scan prelearning. Results show that functional connectivity between the PHG and the hippocampus is positively related to participants' self-reported navigational ability. On the other hand, connectivity with the caudate nucleus correlated negatively with navigational ability. These results are in line with a distinction between egocentric and allocentric spatial representations in the caudate nucleus and the hippocampus, respectively. Our results thus suggest a relation between navigational ability and a neural preference for a specific type of spatial representation. Together, these results show that the PHG is immediately involved in the encoding of navigationally relevant object information. Furthermore, they provide insight into the neural correlates of individual differences in spatial ability. PMID:21671733

  14. Bio-inspired polarized skylight navigation: a review

    Science.gov (United States)

    Zhang, Xi; Wan, Yongqin; Li, Lijing

    2015-12-01

    The idea of using skylight polarization in navigation is learned from animals such as desert ants and honeybees. Various research groups have been working on the development of novel navigation systems inspired by polarized skylight. The research of background in polarized skylight navigation is introduced, and basic principle of the insects navigation is expatiated. Then, the research progress status at home and abroad in skylight polarization pattern, three bio-inspired polarized skylight navigation sensors and polarized skylight navigation are reviewed. Finally, the research focuses in the field of polarized skylight navigation are analyzed. At the same time, the trend of development and prospect in the future are predicted. It is believed that the review is helpful to people understand polarized skylight navigation and polarized skylight navigation sensors.

  15. Tactile object exploration using cursor navigation sensors

    DEFF Research Database (Denmark)

    Kraft, Dirk; Bierbaum, Alexander; Kjaergaard, Morten; Ratkevicius, Jurgis; Kjær-Nielsen, Anders; Ryberg, Charlotte; Petersen, Henrik Gordon; Asfour, Tamim; Dillmann, Ruediger; Krüger, Norbert

    2009-01-01

    In robotic applications tactile sensor systems serve the purpose of localizing a contact point and measuring contact forces. We have investigated the applicability of a sensorial device commonly used in cursor navigation technology for tactile sensing in robotics. We show the potential of this...

  16. Navigation Architecture For A Space Mobile Network

    Science.gov (United States)

    Valdez, Jennifer E.; Ashman, Benjamin; Gramling, Cheryl; Heckler, Gregory W.; Carpenter, Russell

    2016-01-01

    The Tracking and Data Relay Satellite System (TDRSS) Augmentation Service for Satellites (TASS) is a proposed beacon service to provide a global, space-based GPS augmentation service based on the NASA Global Differential GPS (GDGPS) System. The TASS signal will be tied to the GPS time system and usable as an additional ranging and Doppler radiometric source. Additionally, it will provide data vital to autonomous navigation in the near Earth regime, including space weather information, TDRS ephemerides, Earth Orientation Parameters (EOP), and forward commanding capability. TASS benefits include enhancing situational awareness, enabling increased autonomy, and providing near real-time command access for user platforms. As NASA Headquarters Space Communication and Navigation Office (SCaN) begins to move away from a centralized network architecture and towards a Space Mobile Network (SMN) that allows for user initiated services, autonomous navigation will be a key part of such a system. This paper explores how a TASS beacon service enables the Space Mobile Networking paradigm, what a typical user platform would require, and provides an in-depth analysis of several navigation scenarios and operations concepts.

  17. Orchard navigation using derivative free Kalman filtering

    DEFF Research Database (Denmark)

    Hansen, Søren; Bayramoglu, Enis; Andersen, Jens Christian;

    2011-01-01

    This paper describes the use of derivative free filters for mobile robot localization and navigation in an orchard. The localization algorithm fuses odometry and gyro measurements with line features representing the surrounding fruit trees of the orchard. The line features are created on basis of...

  18. 46 CFR 120.420 - Navigation lights.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Navigation lights. 120.420 Section 120.420 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SMALL PASSENGER VESSELS CARRYING MORE THAN 150 PASSENGERS OR WITH OVERNIGHT ACCOMMODATIONS FOR MORE THAN 49 PASSENGERS ELECTRICAL INSTALLATION...

  19. Navigating the Bio-Politics of Childhood

    Science.gov (United States)

    Lee, Nick; Motzkau, Johanna

    2011-01-01

    Childhood research has long shared a bio-political terrain with state agencies in which children figure primarily as "human futures". In the 20th century bio-social dualism helped to make that terrain navigable by researchers, but, as life processes increasingly become key sites of bio-political action, bio-social dualism is becoming less useful…

  20. Indoor Autonomous Airship Control and Navigation System

    OpenAIRE

    Fedorenko Roman; Krukhmalev Victor

    2016-01-01

    The paper presents an automatic control system for autonomous airship. The system is designed to organize autonomous flight of the mini-airship performing flight mission defined from ground control station. Structure, hardware and software implementation of indoor autonomous airship and its navigation and control system as well as experiment results are described.

  1. Indoor Autonomous Airship Control and Navigation System

    Directory of Open Access Journals (Sweden)

    Fedorenko Roman

    2016-01-01

    Full Text Available The paper presents an automatic control system for autonomous airship. The system is designed to organize autonomous flight of the mini-airship performing flight mission defined from ground control station. Structure, hardware and software implementation of indoor autonomous airship and its navigation and control system as well as experiment results are described.

  2. Spatial abstraction for autonomous robot navigation.

    Science.gov (United States)

    Epstein, Susan L; Aroor, Anoop; Evanusa, Matthew; Sklar, Elizabeth I; Parsons, Simon

    2015-09-01

    Optimal navigation for a simulated robot relies on a detailed map and explicit path planning, an approach problematic for real-world robots that are subject to noise and error. This paper reports on autonomous robots that rely on local spatial perception, learning, and commonsense rationales instead. Despite realistic actuator error, learned spatial abstractions form a model that supports effective travel. PMID:26227680

  3. Autonomous system for cross-country navigation

    Science.gov (United States)

    Stentz, Anthony; Brumitt, Barry L.; Coulter, R. C.; Kelly, Alonzo

    1993-05-01

    Autonomous cross-country navigation is essential for outdoor robots moving about in unstructured environments. Most existing systems use range sensors to determine the shape of the terrain, plan a trajectory that avoids obstacles, and then drive the trajectory. Performance has been limited by the range and accuracy of sensors, insufficient vehicle-terrain interaction models, and the availability of high-speed computers. As these elements improve, higher- speed navigation on rougher terrain becomes possible. We have developed a software system for autonomous navigation that provides for greater capability. The perception system supports a large braking distance by fusing multiple range images to build a map of the terrain in front of the vehicle. The system identifies range shadows and interpolates undersamples regions to account for rough terrain effects. The motion planner reduces computational complexity by investigating a minimum number of trajectories. Speeds along the trajectory are set to provide for dynamic stability. The entire system was tested in simulation, and a subset of the capability was demonstrated on a real vehicle. Results to date include a continuous 5.1 kilometer run across moderate terrain with obstacles. This paper begins with the applications, prior work, limitations, and current paradigms for autonomous cross-country navigation, and then describes our contribution to the area.

  4. Spatial Navigation in Preclinical Alzheimer's Disease.

    Science.gov (United States)

    Allison, Samantha L; Fagan, Anne M; Morris, John C; Head, Denise

    2016-02-01

    Although several previous studies have demonstrated navigational deficits in early-stage symptomatic Alzheimer's disease (AD), navigational abilities in preclinical AD have not been examined. The present investigation examined the effects of preclinical AD and early-stage symptomatic AD on spatial navigation performance. Performance on tasks of wayfinding and route learning in a virtual reality environment were examined. Comparisons were made across the following three groups: Clinically normal without preclinical AD (n = 42), clinically normal with preclinical AD (n = 13), and early-stage symptomatic AD (n = 16) groups. Preclinical AD was defined based on cerebrospinal fluid Aβ42 levels below 500 pg/ml. Preclinical AD was associated with deficits in the use of a wayfinding strategy, but not a route learning strategy. Moreover, post-hoc analyses indicated that wayfinding performance had moderate sensitivity and specificity. Results also confirmed early-stage symptomatic AD-related deficits in the use of both wayfinding and route learning strategies. The results of this study suggest that aspects of spatial navigation may be particularly sensitive at detecting the earliest cognitive deficits of AD. PMID:26967209

  5. Imaging, Navigation, and Robotics in Spine Surgery.

    Science.gov (United States)

    Johnson, Norbert

    2016-04-01

    Spinal technology involves imaging, navigation, and robotics-collectively known as "image-guided therapy." Imaging coupled with navigation enhances visualization of irregular anatomy, enabling less invasive procedures. With robotics surgeons can perform quicker and safer hand movements with increased accuracy. In the 1890s, X-rays were invented by Roentgen. The first piece of X-ray equipment, the Cryptoscope, would take an image for 15 minutes, with the surgeon placing his hand in front of the beam to guide calibration; radiation exposure for both surgeon and patient was extreme. In the 1950s, fluoroscopy (C-arm) was invented. In the 1970s, computer-assisted tomography (CAT), known as CAT scan, became available; magnetic resonance imaging had its beginnings in the 1980s, and in 1985, the first robotic surgery was performed to obtain a neurosurgical biopsy specimen. The concept of navigation was introduced in the 1990s, and today's niche products for navigation came onto the market in the 2000s. PMID:27015071

  6. THE ATACAMA COSMOLOGY TELESCOPE: PHYSICAL PROPERTIES OF SUNYAEV-ZEL'DOVICH EFFECT CLUSTERS ON THE CELESTIAL EQUATOR ,

    International Nuclear Information System (INIS)

    We present the optical and X-ray properties of 68 galaxy clusters selected via the Sunyaev-Zel'dovich (SZ) effect at 148 GHz by the Atacama Cosmology Telescope (ACT). Our sample, from an area of 504 deg2 centered on the celestial equator, is divided into two regions. The main region uses 270 deg2 of the ACT survey that overlaps with the co-added ugriz imaging from the Sloan Digital Sky Survey (SDSS) over Stripe 82 plus additional near-infrared pointed observations with the Apache Point Observatory 3.5 m telescope. We confirm a total of 49 clusters to z ≈ 1.3, of which 22 (all at z > 0.55) are new discoveries. For the second region, the regular-depth SDSS imaging allows us to confirm 19 more clusters up to z ≈ 0.7, of which 10 systems are new. We present the optical richness, photometric redshifts, and separation between the SZ position and the brightest cluster galaxy (BCG). We find no significant offset between the cluster SZ centroid and BCG location and a weak correlation between optical richness and SZ-derived mass. We also present X-ray fluxes and luminosities from the ROSAT All Sky Survey which confirm that this is a massive sample. One of the newly discovered clusters, ACT-CL J0044.4+0113 at z = 1.1 (photometric), has an integrated XMM-Newton X-ray temperature of kTX = 7.9 ± 1.0 keV and combined mass of M 200a = 8.2+3.3–2.5 × 1014 h –170 M ☉, placing it among the most massive and X-ray-hot clusters known at redshifts beyond z = 1. We also highlight the optically rich cluster ACT-CL J2327.4–0204 (RCS2 2327) at z = 0.705 (spectroscopic) as the most significant detection of the whole equatorial sample with a Chandra-derived mass of M 200a = 1.9+0.6–0.4 × 1015 h –170 M ☉, placing it in the ranks of the most massive known clusters like El Gordo and the Bullet Cluster.

  7. THE ATACAMA COSMOLOGY TELESCOPE: PHYSICAL PROPERTIES OF SUNYAEV-ZEL'DOVICH EFFECT CLUSTERS ON THE CELESTIAL EQUATOR {sup ,}

    Energy Technology Data Exchange (ETDEWEB)

    Menanteau, Felipe; Hughes, John P. [Department of Physics and Astronomy, Rutgers University, 136 Frelinghuysen Road, Piscataway, NJ 08854 (United States); Sifon, Cristobal; Barrientos, L. Felipe; Duenner, Rolando; Infante, Leopoldo [Departamento de Astronomia y Astrofisica, Facultad de Fisica, Pontificia Universidad Catolica de Chile, Casilla 306, Santiago 22 (Chile); Battaglia, Nicholas [McWilliams Center for Cosmology, Department of Physics, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA 15213 (United States); Bond, J. Richard; Hajian, Amir; Hincks, Adam D. [Canadian Institute for Theoretical Astrophysics, University of Toronto, Toronto, ON M5S 3H8 (Canada); Crichton, Devin; Gralla, Megan; Marriage, Tobias A. [Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, MD 21218-2686 (United States); Das, Sudeep [High Energy Physics Division, Argonne National Laboratory, 9700 S Cass Avenue, Lemont, IL 60439 (United States); Devlin, Mark J.; Dicker, Simon [Department of Physics and Astronomy, University of Pennsylvania, 209 South 33rd Street, Philadelphia, PA 19104 (United States); Hasselfield, Matthew [Department of Physics and Astronomy, University of British Columbia, Vancouver, BC V6T 1Z4 (Canada); Hilton, Matt [Astrophysics and Cosmology Research Unit, School of Mathematics, Statistics and Computer Science, University of KwaZulu-Natal, Durban (South Africa); Kosowsky, Arthur [Physics and Astronomy Department, University of Pittsburgh, 100 Allen Hall, 3941 O' Hara Street, Pittsburgh, PA 15260 (United States); Marsden, Danica [Department of Physics, University of California Santa Barbara, CA 93106 (United States); and others

    2013-03-01

    We present the optical and X-ray properties of 68 galaxy clusters selected via the Sunyaev-Zel'dovich (SZ) effect at 148 GHz by the Atacama Cosmology Telescope (ACT). Our sample, from an area of 504 deg{sup 2} centered on the celestial equator, is divided into two regions. The main region uses 270 deg{sup 2} of the ACT survey that overlaps with the co-added ugriz imaging from the Sloan Digital Sky Survey (SDSS) over Stripe 82 plus additional near-infrared pointed observations with the Apache Point Observatory 3.5 m telescope. We confirm a total of 49 clusters to z Almost-Equal-To 1.3, of which 22 (all at z > 0.55) are new discoveries. For the second region, the regular-depth SDSS imaging allows us to confirm 19 more clusters up to z Almost-Equal-To 0.7, of which 10 systems are new. We present the optical richness, photometric redshifts, and separation between the SZ position and the brightest cluster galaxy (BCG). We find no significant offset between the cluster SZ centroid and BCG location and a weak correlation between optical richness and SZ-derived mass. We also present X-ray fluxes and luminosities from the ROSAT All Sky Survey which confirm that this is a massive sample. One of the newly discovered clusters, ACT-CL J0044.4+0113 at z = 1.1 (photometric), has an integrated XMM-Newton X-ray temperature of kT{sub X} = 7.9 {+-} 1.0 keV and combined mass of M {sub 200a} = 8.2{sup +3.3} {sub -2.5} Multiplication-Sign 10{sup 14} h {sup -1} {sub 70} M {sub Sun }, placing it among the most massive and X-ray-hot clusters known at redshifts beyond z = 1. We also highlight the optically rich cluster ACT-CL J2327.4-0204 (RCS2 2327) at z = 0.705 (spectroscopic) as the most significant detection of the whole equatorial sample with a Chandra-derived mass of M {sub 200a} = 1.9{sup +0.6} {sub -0.4} Multiplication-Sign 10{sup 15} h {sup -1} {sub 70} M {sub Sun }, placing it in the ranks of the most massive known clusters like El Gordo and the Bullet Cluster.

  8. Evaluation of navigation interfaces in virtual environments

    Science.gov (United States)

    Mestre, Daniel R.

    2014-02-01

    When users are immersed in cave-like virtual reality systems, navigational interfaces have to be used when the size of the virtual environment becomes larger than the physical extent of the cave floor. However, using navigation interfaces, physically static users experience self-motion (visually-induced vection). As a consequence, sensorial incoherence between vision (indicating self-motion) and other proprioceptive inputs (indicating immobility) can make them feel dizzy and disoriented. We tested, in two experimental studies, different locomotion interfaces. The objective was twofold: testing spatial learning and cybersickness. In a first experiment, using first-person navigation with a flystick ®, we tested the effect of sensorial aids, a spatialized sound or guiding arrows on the ground, attracting the user toward the goal of the navigation task. Results revealed that sensorial aids tended to impact negatively spatial learning. Moreover, subjects reported significant levels of cybersickness. In a second experiment, we tested whether such negative effects could be due to poorly controlled rotational motion during simulated self-motion. Subjects used a gamepad, in which rotational and translational displacements were independently controlled by two joysticks. Furthermore, we tested first- versus third-person navigation. No significant difference was observed between these two conditions. Overall, cybersickness tended to be lower, as compared to experiment 1, but the difference was not significant. Future research should evaluate further the hypothesis of the role of passively perceived optical flow in cybersickness, but manipulating the virtual environment'sperrot structure. It also seems that video-gaming experience might be involved in the user's sensitivity to cybersickness.

  9. Navigated Waterways of Louisiana, Geographic NAD83, LOSCO (1999) [navigated_waterways_LOSCO_1999

    Data.gov (United States)

    Louisiana Geographic Information Center — This is a line dataset of navigated waterways fitting the LOSCO definition: it has been traveled by vessels transporting 10,000 gallons of oil or fuel as determined...

  10. 33 CFR 2.36 - Navigable waters of the United States, navigable waters, and territorial waters.

    Science.gov (United States)

    2010-07-01

    ... GUARD, DEPARTMENT OF HOMELAND SECURITY GENERAL JURISDICTION Jurisdictional Terms § 2.36 Navigable waters... used in sections 311 and 312 of the Federal Water Pollution Control Act, as amended, 33 U.S.C. 1321...

  11. Wayfinding and Navigation for People with Disabilities Using Social Navigation Networks

    Directory of Open Access Journals (Sweden)

    Hassan A. Karimi

    2014-10-01

    Full Text Available To achieve safe and independent mobility, people usually depend on published information, prior experience, the knowledge of others, and/or technology to navigate unfamiliar outdoor and indoor environments. Today, due to advances in various technologies, wayfinding and navigation systems and services are commonplace and are accessible on desktop, laptop, and mobile devices. However, despite their popularity and widespread use, current wayfinding and navigation solutions often fail to address the needs of people with disabilities (PWDs. We argue that these shortcomings are primarily due to the ubiquity of the compute-centric approach adopted in these systems and services, where they do not benefit from the experience-centric approach. We propose that following a hybrid approach of combining experience-centric and compute-centric methods will overcome the shortcomings of current wayfinding and navigation solutions for PWDs.

  12. Lunar Navigator - A Miniature, Fully Autonomous, Lunar Navigation, Surveyor, and Range Finder System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Microcosm proposes to design and develop a fully autonomous Lunar Navigator based on our MicroMak miniature star sensor and a gravity gradiometer similar to one on...

  13. 77 FR 45991 - Regulated Navigation Area; Buzzard's Bay, MA; Navigable Waterways Within the First Coast Guard...

    Science.gov (United States)

    2012-08-02

    ...The Coast Guard announces the availability of a draft Environmental Assessment (EA) considering the reasonably foreseeable environmental impacts and socioeconomic effects of implementing a Regulated Navigation Area in Buzzard's Bay, MA. We request your comments on the draft...

  14. Lunar Navigator - A Miniature, Fully Autonomous, Lunar Navigation, Surveyor, and Range Finder System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Microcosm will use existing hardware and software from related programs to create a prototype Lunar Navigation Sensor (LNS) early in Phase II, such that most of the...

  15. Spinal navigation in combination with intraoperative computed tomography; Spinale Navigation in Kombination mit der intraoperativen Computertomographie

    Energy Technology Data Exchange (ETDEWEB)

    Haberland, N.; Ebmeier, K.; Hliscs, R.; Grunewald, J.P.; Kalff, R.L. [Neurochirurgische Klinik und Poliklinik, Klinikum der Friedrich-Schiller-Univ. Jena (Germany)

    2000-02-01

    Assisted by the mobile Tomoscan M CT system, titanium pedicle screw placement markers can be implanted into the vertebral segments prior to CT data acquisition for surgical navigation. This approach significantly enhances the spinal navigation accuracy. (orig./CB) [German] Mit Hilfe des mobilen CT-Systems Tomoscan M koennen Titanschraubmarker vor der CT-Datenakquisition in die Wirbelsegmente implantiert werden. Das fuehrt zu wesentlich hoeherer Applikationsgenauigkeit am Zielpunkt. (orig.)

  16. Zasnova mobilne multimodalne komunikacijske naprave - osebni navigator: The design of mobile multimodal communication device - personal navigator:

    OpenAIRE

    Horvat, Bogomir; Horvat, Boštjan; Kačič, Zdravko; Kotnik, Bojan; Kramberger, Iztok; Rotovnik, Tomaž

    2001-01-01

    In today's world there are increasing demands for products that would enable a palette of services and would be portable, light, small and ergonomically designed. Their handling, however, should be as simple as possible, e.g. voice driven. Demands like that have brought about an integration of different technologies. The concept of the device which we describe in this article is called personal navigator. Personal navigator presents a multimodal communication device. It enables the user visua...

  17. Science Benefits of Onboard Spacecraft Navigation

    Science.gov (United States)

    Cangahuala, Al; Bhaskaran, Shyam; Owen, Bill

    2012-01-01

    Primitive bodies (asteroids and comets), which have remained relatively unaltered since their formation, are important targets for scientific missions that seek to understand the evolution of the solar system. Often the first step is to fly by these bodies with robotic spacecraft. The key to maximizing data returns from these flybys is to determine the spacecraft trajectory relative to the target body-in short, navigate the spacecraft- with sufficient accuracy so that the target is guaranteed to be in the instruments' field of view. The most powerful navigation data in these scenarios are images taken by the spacecraft of the target against a known star field (onboard astrometry). Traditionally, the relative trajectory of the spacecraft must be estimated hours to days in advance using images collected by the spacecraft. This is because of (1)!the long round-trip light times between the spacecraft and the Earth and (2)!the time needed to downlink and process navigation data on the ground, make decisions based on the result, and build and uplink instrument pointing sequences from the results. The light time and processing time compromise navigation accuracy considerably, because there is not enough time to use more accurate data collected closer to the target-such data are more accurate because the angular capability of the onboard astrometry is essentially constant as the distance to the target decreases, resulting in better "plane-of- sky" knowledge of the target. Excellent examples of these timing limitations are high-speed comet encounters. Comets are difficult to observe up close; their orbits often limit scientists to brief, rapid flybys, and their coma further restricts viewers from seeing the nucleus in any detail, unless they can view the nucleus at close range. Comet nuclei details are typically discernable for much shorter durations than the roundtrip light time to Earth, so robotic spacecraft must be able to perform onboard navigation. This onboard

  18. Spinal navigation in combination with intraoperative computed tomography

    International Nuclear Information System (INIS)

    Assisted by the mobile Tomoscan M CT system, titanium pedicle screw placement markers can be implanted into the vertebral segments prior to CT data acquisition for surgical navigation. This approach significantly enhances the spinal navigation accuracy. (orig./CB)

  19. LiAISON: Linked, Autonomous Interplanetary Satellite Orbit Navigation Project

    Data.gov (United States)

    National Aeronautics and Space Administration — A new navigation technique known as LiAISON (Linked Autonomous Interplanetary Satellite Orbit Navigation) may be used to propel the benefits of GPS to new orbits,...

  20. Effects of active navigation on object recognition in virtual environments.

    Science.gov (United States)

    Hahm, Jinsun; Lee, Kanghee; Lim, Seung-Lark; Kim, Sei-Young; Kim, Hyun-Taek; Lee, Jang-Han

    2007-04-01

    We investigated the importance and efficiency of active and passive exploration on the recognition of objects in a variety of virtual environments (VEs). In this study, 54 participants were randomly allocated into one of active and passive navigation conditions. Active navigation was performed by allowing participants to self-pace and control their own navigation, but passive navigation was conducted by forced navigation. After navigating VEs, participants were asked to recognize the objects that had been in the VEs. Active navigation condition had a significantly higher percentage of hit responses (t (52) = 4.000, p object recognition than the passive condition. These results suggest that active navigation plays an important role in spatial cognition as well as providing an explanation for the efficiency of learning in a 3D-based program. PMID:17474852

  1. Complementary terrain/single beacon-based AUV navigation

    Digital Repository Service at National Institute of Oceanography (India)

    Maurya, P.; Curado, T.F.; António, P.

    This paper describes work done towards the development of advanced geophysical-based navigation systems for autonomous underwater vehicles (AUVs). The specific problem that we tackle is that of combining terrain-aided navigation (TAN) with single...

  2. Olfaction Contributes to Pelagic Navigation in a Coastal Shark

    OpenAIRE

    Nosal, Andrew P.; Chao, Yi; Farrara, John D.; Chai, Fei; Hastings, Philip A.

    2016-01-01

    How animals navigate the constantly moving and visually uniform pelagic realm, often along straight paths between distant sites, is an enduring mystery. The mechanisms enabling pelagic navigation in cartilaginous fishes are particularly understudied. We used shoreward navigation by leopard sharks (Triakis semifasciata) as a model system to test whether olfaction contributes to pelagic navigation. Leopard sharks were captured alongshore, transported 9 km offshore, released, and acoustically tr...

  3. Hybrid Navigation using Sensor Fusion in Hand-Held Devices

    OpenAIRE

    Calero Scanlan, David

    2013-01-01

    This thesis analyses the performance that can be obtained in navigation applications by using the camera and sensors embedded in a mobile phone (and GPS when available). The project includes the development of image processing algorithms to extract useful observations for navigation. Navigation is based on the determination of the trajectory, ie, time, position, velocity and altitude. For a good navigation experience a period of calibration and characterization of embedded mobile sensors such...

  4. INDOOR POSITIONING AND NAVIGATION BASED ON CONTROL SPHERECAL PANORAMIC IMAGES

    OpenAIRE

    Huang, Tsung-Che; Tseng, Yi-Hsing

    2016-01-01

    Continuous indoor and outdoor positioning and navigation is the goal to achieve in the field of mobile mapping technology. However, accuracy of positioning and navigation will be largely degraded in indoor or occluded areas, due to receiving weak or less GNSS signals. Targeting the need of high accuracy indoor and outdoor positioning and navigation for mobile mapping applications, the objective of this study is to develop a novel method of indoor positioning and navigation with the use of sph...

  5. Visibility Research of X-ray Pulsar-based Navigation for Interplanetary Explore%行星际探测X射线脉冲星导航可见性研究

    Institute of Scientific and Technical Information of China (English)

    薛舜; 张科; 吕梅柏

    2014-01-01

    X射线脉冲星能为行星际探测提供自主运营、高精度的导航服务。行星际探测过程中脉冲星并非随时可见,如何选择脉冲星关系到该导航方法的可行性。本文利用脉冲星、航天器及第三天体位置关系从几何角度研究脉冲星可见性问题,证明了在绝对定位导航中第三天体遮挡与干扰问题的解的等价性并给出了基于可见性的脉冲星优先选择准则;研究了X射线探测器姿态运动对脉冲星探测的影响,引入姿态转移矩阵解决了脉冲星实时可见性问题;研究了第三天体位置对两个航天器间通讯链路畅阻的影响,给出了基于X射线脉冲星的相对定位导航时机。有关可见性问题而建立的脉冲星选择准则,为行星际探测X射线脉冲星导航的工程应用提供了基础。%X-ray pulsar-based navigation as a complete independence and high precision navigation method could be used for interplanetary exploration. How to choose pulsars will ultimately decide its feasibility, because pulsars visibility is a problem. Firstly, the paper computed the angles among pulsars, space probes and celestial bodies to research the visibility ingeometry way, concluded a united pulsars visible solution for planets eclipse and the Sun jamming, and then built navigation pulsars choice priority criterion in the absolute localization. Secondly, state transition matrix was introduced to research real time visibility when space probe’s attitude moving disturbed detector pointing. Finally, the paper researched the situation of communication link affecting by celestial body location between two probes and concluded the feasibility time of using relative navigation. These researches on building navigation pulsars choice criterion in visibility will be a foundation of using X-ray pulsar-based navigation for interplanetary explore.

  6. 33 CFR 64.31 - Determination of hazard to navigation.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Determination of hazard to... Provisions § 64.31 Determination of hazard to navigation. In determining whether an obstruction is a hazard... vessel incidents involving the obstruction; and (k) Whether the obstruction is defined as a hazard...

  7. Private Graphs - Access Rights on Graphs for Seamless Navigation

    Science.gov (United States)

    Dorner, W.; Hau, F.; Pagany, R.

    2016-06-01

    After the success of GNSS (Global Navigational Satellite Systems) and navigation services for public streets, indoor seems to be the next big development in navigational services, relying on RTLS - Real Time Locating Services (e.g. WIFI) and allowing seamless navigation. In contrast to navigation and routing services on public streets, seamless navigation will cause an additional challenge: how to make routing data accessible to defined users or restrict access rights for defined areas or only to parts of the graph to a defined user group? The paper will present case studies and data from literature, where seamless and especially indoor navigation solutions are presented (hospitals, industrial complexes, building sites), but the problem of restricted access rights was only touched from a real world, but not a technical perspective. The analysis of case studies will show, that the objective of navigation and the different target groups for navigation solutions will demand well defined access rights and require solutions, how to make only parts of a graph to a user or application available to solve a navigational task. The paper will therefore introduce the concept of private graphs, which is defined as a graph for navigational purposes covering the street, road or floor network of an area behind a public street and suggest different approaches how to make graph data for navigational purposes available considering access rights and data protection, privacy and security issues as well.

  8. Flat-detector CT-based electromagnetic navigation

    International Nuclear Information System (INIS)

    Flat-detector CT coupled to an angiography device provides an imaging technique for interventions which can be used for electromagnetically navigated percutaneous punctures. This report explains the functionality of an electromagnetic navigation system and describes the course of an electromagnetically navigated puncture and the capabilities of such a system in the clinical routine. (orig.)

  9. A New Navigation Strategy in Hypermedia Integral Ware Authoring System

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    After analyzing the general navigation mechanisms and discussing the knowledge point card linking model which is the base of the navigation mechanism used in the Hypermedia Integral ware Authoring System(HIAS), the paper presents a new navigation strategy in HIAS. And the application trend of HIAS is discussed at last.

  10. 47 CFR 22.365 - Antenna structures; air navigation safety.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Antenna structures; air navigation safety. 22... Antenna structures; air navigation safety. Licensees that own their antenna structures must not allow these antenna structures to become a hazard to air navigation. In general, antenna structure owners...

  11. Time and Motion Study of a Community Patient Navigator

    Directory of Open Access Journals (Sweden)

    Sara S. Phillips

    2014-04-01

    Full Text Available Research on patient navigation has focused on validating the utility of navigators by defining their roles and analyzing their effects on patient outcomes, patient satisfaction, and cost effectiveness. Patient navigators are increasingly used outside the research context, and their roles without research responsibilities may look very different. This pilot study captured the activities of a community patient navigator for uninsured women with a positive screening test for breast cancer, using a time and motion approach over a period of three days. We followed the actions of this navigator minute by minute to assess the relative ratios of actions performed and to identify areas for time efficiency improvement to increase direct time with patients. This novel approach depicts the duties of a community patient navigator no longer fettered by navigation logs, research team meetings, surveys, and the consent process. We found that the community patient navigator was able to spend more time with patients in the clinical context relative to performing paperwork or logging communication with patients as a result of her lack of research responsibilities. By illuminating how community patient navigation functions as separate from the research setting, our results will inform future hiring and training of community patient navigators, system design and operations for improving the efficiency and efficacy of navigators, and our understanding of what community patient navigators do in the absence of research responsibilities.

  12. Fault-tolerant Sensor Fusion for Marine Navigation

    DEFF Research Database (Denmark)

    Blanke, Mogens

    2006-01-01

    Reliability of navigation data are critical for steering and manoeuvring control, and in particular so at high speed or in critical phases of a mission. Should faults occur, faulty instruments need be autonomously isolated and faulty information discarded. This paper designs a navigation solution...... events where the fault-tolerant sensor fusion provided uninterrupted navigation data despite temporal instrument defects...

  13. Robot navigation system using intrinsic evolvable hardware

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Recently there has been great interest in the idea that evolvable system based on the principle of ar tifcial intelligence can be used to continuously and autonomously adapt the behaviour of physically embedded systems such as autonomous mobile robots and intelligent home devices. Meanwhile, we have seen the introduc tion of evolvable hardware(EHW): new integrated electronic circuits that are able to continuously evolve to a dapt the chages in the environment implemented by evolutionary algorithms such as genetic algorithm(GA)and reinforcement learning. This paper concentrates on developing a robotic navigation system whose basic behav iours are obstacle avoidance and light source navigation. The results demonstrate that the intrinsic evolvable hardware system is able to create the stable robotiiuc behaviours as required in the real world instead of the tra ditional hardware systems.

  14. A wayfinding aid to increase navigator independence

    Directory of Open Access Journals (Sweden)

    Wilfred Waters

    2011-12-01

    Full Text Available Wayfinding aids are of great benefit because users do not have to rely on their learned geographic knowledge or orientation skills alone for successful navigation. Additionally, cognitive resources usually captured by this activity can be spent elsewhere. A challenge, however, remains for wayfinding aid developers. Due to the automation of wayfinding aids, navigator independence may be decreasing via the use of these aids. In order to address this, wayfinding aids might be improved additionally to perform a training role. Since the most versatile wayfinders appear to deploy a dual strategy for geographic orientation, it is proposed that wayfinding aids be improved to foster such an approach. This paper presents the results of an experimental study testing a portion of the suggested enhancement.

  15. Autonomous rough terrain navigation - Lessons learned

    Science.gov (United States)

    Miller, David P.

    1991-01-01

    Because of light-time delays, a planetary rover located on Mars or beyond will probably need to be able to navigate autonomously, in order to do significant exploration. Recent work at JPL has explored several different autonomous navigation strategies. This work includes highly deliberative methods that require large amounts of computation and internal storage but yield very planful behavior to more reactive systems that require less resources but whose behavior is more difficult to model. This paper briefly presents these methods, the results from experiments both in simulation and in the field, and some conclusions on the value of different approaches, and their possible impact on the structure of the robot and the mission architecture.

  16. Navigational mechanisms of migrating monarch butterflies.

    Science.gov (United States)

    Reppert, Steven M; Gegear, Robert J; Merlin, Christine

    2010-09-01

    Recent studies of the iconic fall migration of monarch butterflies have illuminated the mechanisms behind their southward navigation while using a time-compensated sun compass. Skylight cues, such as the sun itself and polarized light, are processed through both eyes and are probably integrated in the brain's central complex, the presumed site of the sun compass. Time compensation is provided by circadian clocks that have a distinctive molecular mechanism and that reside in the antennae. Monarchs might also use a magnetic compass because they possess two cryptochromes that have the molecular capability for light-dependent magnetoreception. Multiple genomic approaches are now being used with the aim of identifying navigation genes. Monarch butterflies are thus emerging as an excellent model organism in which to study the molecular and neural basis of long-distance migration. PMID:20627420

  17. Development of autonomous grasping and navigating robot

    Science.gov (United States)

    Kudoh, Hiroyuki; Fujimoto, Keisuke; Nakayama, Yasuichi

    2015-01-01

    The ability to find and grasp target items in an unknown environment is important for working robots. We developed an autonomous navigating and grasping robot. The operations are locating a requested item, moving to where the item is placed, finding the item on a shelf or table, and picking the item up from the shelf or the table. To achieve these operations, we designed the robot with three functions: an autonomous navigating function that generates a map and a route in an unknown environment, an item position recognizing function, and a grasping function. We tested this robot in an unknown environment. It achieved a series of operations: moving to a destination, recognizing the positions of items on a shelf, picking up an item, placing it on a cart with its hand, and returning to the starting location. The results of this experiment show the applicability of reducing the workforce with robots.

  18. An approximate model for pulsar navigation simulation

    Science.gov (United States)

    Jovanovic, Ilija; Enright, John

    2016-02-01

    This paper presents an approximate model for the simulation of pulsar aided navigation systems. High fidelity simulations of these systems are computationally intensive and impractical for simulating periods of a day or more. Simulation of yearlong missions is done by abstracting navigation errors as periodic Gaussian noise injections. This paper presents an intermediary approximate model to simulate position errors for periods of several weeks, useful for building more accurate Gaussian error models. This is done by abstracting photon detection and binning, replacing it with a simple deterministic process. The approximate model enables faster computation of error injection models, allowing the error model to be inexpensively updated throughout a simulation. Testing of the approximate model revealed an optimistic performance prediction for non-millisecond pulsars with more accurate predictions for pulsars in the millisecond spectrum. This performance gap was attributed to noise which is not present in the approximate model but can be predicted and added to improve accuracy.

  19. Design of Evolvable Hardware for Robotic Navigation

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    This paper presents an integrated on-line learning system toevolve programmabl e logic array (PLA) controllers for navigating an autonomous robot in a two-dime n sional environment. The integrated on-line learning system consists of two lear n ing modules: one is the module of reinforcement learning based on temporal-diff e rence learning based on genetic algorithms, and the other is the module of evolu tionary learning based on genetic algorithms. The control rules extracted from t he module of reinforcement learning can be used as input to the module of evolut ionary learning, and quickly implemented by the PLA through on-line evolution. T he on-line evolution has shown promise as a method of learning systems in compl e x environment. The evolved PLA controllers can successfully navigate the robot t o a target in the two-dimensional environment while avoiding collisions with ra ndomly positioned obstacles.

  20. Automatic document navigation for digital content remastering

    Science.gov (United States)

    Lin, Xiaofan; Simske, Steven J.

    2003-12-01

    This paper presents a novel method of automatically adding navigation capabilities to re-mastered electronic books. We first analyze the need for a generic and robust system to automatically construct navigation links into re-mastered books. We then introduce the core algorithm based on text matching for building the links. The proposed method utilizes the tree-structured dictionary and directional graph of the table of contents to efficiently conduct the text matching. Information fusion further increases the robustness of the algorithm. The experimental results on the MIT Press digital library project are discussed and the key functional features of the system are illustrated. We have also investigated how the quality of the OCR engine affects the linking algorithm. In addition, the analogy between this work and Web link mining has been pointed out.

  1. Reactive navigational controller for autonomous mobile robots

    Science.gov (United States)

    Hawkins, Scott

    1993-12-01

    Autonomous mobile robots must respond to external challenges and threats in real time. One way to satisfy this requirement is to use a fast low level intelligence to react to local environment changes. A fast reactive controller has been implemented which performs the task of real time local navigation by integrating primitive elements of perception, planning, and control. Competing achievement and constraint behaviors are used to allow abstract qualitative specification of navigation goals. An interface is provided to allow a higher level deliberative intelligence with a more global perspective to set local goals for the reactive controller. The reactive controller's simplistic strategies may not always succeed, so a means to monitor and redirect the reactive controller is provided.

  2. Advanced Bayesian Method for Planetary Surface Navigation

    Science.gov (United States)

    Center, Julian

    2015-01-01

    Autonomous Exploration, Inc., has developed an advanced Bayesian statistical inference method that leverages current computing technology to produce a highly accurate surface navigation system. The method combines dense stereo vision and high-speed optical flow to implement visual odometry (VO) to track faster rover movements. The Bayesian VO technique improves performance by using all image information rather than corner features only. The method determines what can be learned from each image pixel and weighs the information accordingly. This capability improves performance in shadowed areas that yield only low-contrast images. The error characteristics of the visual processing are complementary to those of a low-cost inertial measurement unit (IMU), so the combination of the two capabilities provides highly accurate navigation. The method increases NASA mission productivity by enabling faster rover speed and accuracy. On Earth, the technology will permit operation of robots and autonomous vehicles in areas where the Global Positioning System (GPS) is degraded or unavailable.

  3. Visual SLAM for Autonomous Navigation of MAVs

    OpenAIRE

    Yang, Shaowu

    2014-01-01

    This thesis focuses on developing onboard visual simultaneous localization and mapping (SLAM) systems to enable autonomous navigation of micro aerial vehicles (MAVs), which is still a challenging topic considering the limited payload and computational capability that an MAV normally has. In MAV applications, the visual SLAM systems are required to be very efficient, especially when other visual tasks have to be done in parallel. Furthermore, robustness in pose tracking is highly desired in or...

  4. Mobile Screens: The Visual Regime of Navigation

    OpenAIRE

    Verhoeff, N.

    2012-01-01

    In this book on screen media, space, and mobility I compare synchronically, as well as diachronically, diverse and variegated screen media - their technologies and practices – as sites for virtual mobility and navigation. Mobility as a central trope can be found on the multiple levels that are investigated. First, the representation of mobility in audiovisual media is concerned with the virtual mobility of media technology in general, and of the change in their possibilities. I analyze the wa...

  5. Pigeon navigation : different routes lead to Frankfurt

    OpenAIRE

    Schiffner, Ingo; Wiltschko, Roswitha

    2014-01-01

    Background: Tracks of pigeons homing to the Frankfurt loft revealed an odd phenomenon: whereas birds returning from the North approach their loft more or less directly in a broad front, pigeons returning from the South choose, from 25 km from home onward, either of two corridors, a direct one and one with a considerable detour to the West. This implies differences in the navigational process. Methodology/Principle Findings: Pigeons released at sites at the beginning of the westerly corrido...

  6. Particle Filters for Positioning, Navigation and Tracking

    OpenAIRE

    Gustafsson, Fredrik; Gunnarsson, Fredrik; Bergman, Niclas; Forssell, Urban; Jansson, Jonas; Karlsson, Rickard; Nordlund, Per-Johan

    2001-01-01

    A framework for positioning, navigation and tracking problems using particle filters (sequential Monte Carlo methods) is developed. It consists of a class of motion models and a general non-linear measurement equation in position. A general algorithm is presented, which is parsimonious with the particle dimension. It is based on marginalization, enabling a Kalman filter to estimate all position derivatives, and the particle filter becomes low-dimensional. This is of utmost importance for high...

  7. Distributed parallel computing using navigational programming

    OpenAIRE

    Pan, Lei; Lai, M. K.; Noguchi, K; Huseynov, J J; L. F. Bic; Dillencourt, M B

    2004-01-01

    Message Passing ( MP) and Distributed Shared Memory (DSM) are the two most common approaches to distributed parallel computing. MP is difficult to use, whereas DSM is not scalable. Performance scalability and ease of programming can be achieved at the same time by using navigational programming (NavP). This approach combines the advantages of MP and DSM, and it balances convenience and flexibility. Similar to MP, NavP suggests to its programmers the principle of pivot-computes and hence is ef...

  8. Interior Design and Navigation in Virtual Reality

    OpenAIRE

    Tingvall, Jesper

    2015-01-01

    This thesis examined how virtual reality could be used in interior design. The thesis was limited to virtual reality experienced using a head mounted display. The Method was to integrate virtual reality into an existing interior design software called CET Designer. After investigating the available commercial virtual reality hardware and software Oculus SDK and OpenVR was chosen. Unity 3D was used as a prototyping tool for experimenting with different interaction and navigation methods. An use...

  9. Pedestrian navigation using the sense of touch

    OpenAIRE

    Jacob, Ricky; Winstanley, Adam; Togher, Naomi; Roche, Richard; Mooney, Peter

    2012-01-01

    Haptics is a feedback technology that takes advantage of the human sense of touch by applying forces, vibrations, and/or motions to a haptic-enabled user device such as a mobile phone. Historically, human–computer interaction has been visual, data, or images on a screen. Haptic feedback can be an important modality in Mobile Location-Based Services like – knowledge discovery, pedestrian navigation and notification systems. In this paper we describe a methodology for the implementa...

  10. Tag trails: Navigating with context and history

    OpenAIRE

    Gwizdka, Jacek; Bakelaar, Philip

    2009-01-01

    We describe a technique for preserving and presenting context and history while navigating web resources described by keywords. We use tagging and tag clouds as an application area for our technique. The technique is illustrated by employing it in a prototype that interfaces data from a social tagging website used to bookmark academic articles. The prototype displays a “tag trail” which can reveal contextual connections between web resources and the associated tags. We argue that the user’s u...

  11. Navigational Mechanisms of Migrating Monarch Butterflies

    OpenAIRE

    Reppert, Steven M.; Gegear, Robert J; Merlin, Christine

    2010-01-01

    Recent studies of the iconic fall migration of monarch butterflies have illuminated the mechanisms behind the navigation south, using a time-compensated sun compass. Skylight cues, such as the sun itself and polarized light, are processed through both eyes and likely integrated in the brain’s central complex, the presumed site of the sun compass. Time compensation is provided by circadian clocks that have a distinctive molecular mechanism and that reside in the antennae. Monarchs may also use...

  12. Identifying Nonstationary Clock Noises in Navigation Systems

    OpenAIRE

    Patrizia Tavella; Lorenzo Galleani

    2008-01-01

    The stability of the atomic clocks on board the satellites of a navigation system should remain constant with time. In reality there are numerous physical phenomena that make the behavior of the clocks a function of time, and for this reason we have recently introduced the dynamic Allan variance (DAVAR), a measure of the time-varying stability of an atomic clock. In this paper we discuss the dynamic Allan variance for phase and frequency jumps, two common nonstationarities of atomic clocks. T...

  13. Navigation of an underwater industrial autonomous vehicle

    Energy Technology Data Exchange (ETDEWEB)

    Korotchentsev, V.I.; Rozenbaum, A.N.; Deshner, A.I. [Rossijskaya Akademiya Nauk, Vladivostok (Russian Federation). Inst. Avtomatiki i Protsessov Upravleniya

    2000-07-01

    This paper suggests a new approach to solving the problem of navigation of an underwater vehicle using arbitrary seafloor relief data. The known methods of building seafloor acoustic maps are not effective for correction of coordinates in areas of smooth relief and in shallow water. The suggested algorithm allows making maps using acoustic sectional view of the seafloor layers. The sectional view is of various forms in different areas of the smooth relief. (orig.)

  14. Simultaneous Navigation and Synthetic Aperture Radar Focusing

    OpenAIRE

    Sjanic, Zoran; Gustafsson, Fredrik

    2015-01-01

    Synthetic aperture radar (SAR) equipment is a radar imaging system that can be used to create high-resolution images of a scene by utilizing the movement of a flying platform. Knowledge of the platforms trajectory is essential to get good and focused images. An emerging application field is real-time SAR imaging using small and cheap platforms where estimation errors in navigation systems imply unfocused images. This contribution investigates a joint estimation of the trajectory and SAR image...

  15. Reactive Robot Navigation Utilizing Nonlinear Control

    OpenAIRE

    Lei Ting; Macnab, Chris J.B.; Sebastian Magierowski

    2014-01-01

    In this paper, we propose a computationally efficient heuristic solution to choosing a path around obstacles in the face of limited sensor information. Specifically, we propose a navigation algorithm for a mobile robot that reaches a measured target position while avoiding obstacles, making decisions in real-time (without stopping) and relying strictly on information obtained from limited and noisy robot-mounted sensors to determine the location and severity of obstacles. The solution utilize...

  16. Biologically Inspired Vision for Indoor Robot Navigation

    OpenAIRE

    Saleiro, Mário; Tersic, K.; Lobato, D.; Rodrigues, J. M. F.; du Buf, J. M. H.

    2014-01-01

    Ultrasonic, infrared, laser and other sensors are being applied in robotics. Although combinations of these have allowed robots to navigate, they are only suited for specific scenarios, depending on their limitations. Recent advances in computer vision are turning cameras into useful low-cost sensors that can operate in most types of environments. Cameras enable robots to detect obstacles, recognize objects, obtain visual odometry, detect and recognize people and gestures, a...

  17. Navigation, perception et apprentissage pour la robotique

    OpenAIRE

    Filliat, David

    2011-01-01

    We conducted research mainly in the areas of navigation, perception and learning for mobile robots. These studies, oriented toward a cognitive approach to robotics have the overall goal of allowing robots to adapt to their environment, providing ba- sic primitives such as open space, position, or the presence of objects necessary to choose actions. A large part of this work is inspired by capabilities found in nature, but without trying to reproduce exactly the biological systems inner functi...

  18. Laboratory experiments in mobile robot navigation

    International Nuclear Information System (INIS)

    Mobile robots have potential applications in remote surveillance and operation in hazardous areas. To be effective, they must have the ability to navigate on their own to desired locations. Several experimental navigational runs of a mobile robot developed have been conducted. The robot has three wheels of which the front wheel is steered and the hind wheels are driven. The robot is equipped with an ultrasonic range sensor, which is turned around to get range data in all directions. The range data is fed to the input of a neural net, whose output steers the robot towards the goal. The robot is powered by batteries (12V 10Ah). It has an onboard stepper motor controller for driving the wheels and the ultrasonic setup. It also has an onboard computer which runs the navigation program NAV. This program sends the range data and configuration parameters to the operator''s console program OCP, running on a stationary PC, through radio communication on a serial line. Through OCP, an operator can monitor the progress of the robot from a distant control room and intervene if necessary. In this paper the control modules of the mobile robot, its ways of operation and also results of some of the experimental runs recorded are reported. It is seen that the trained net guides the mobile robot through gaps of 1m and above to its destination with about 84% success measured over a small sample of 38 runs

  19. Cues indicating location in pigeon navigation.

    Science.gov (United States)

    Beason, Robert C; Wiltschko, Wolfgang

    2015-10-01

    Domesticated Rock Pigeons (Columba livia f. domestica) have been selected for returning home after being displaced. They appear to use many of the physical cue sources available in the natural environment for Map-and-Compass navigation. Two compass mechanisms that have been well documented in pigeons are a time-compensated sun compass and a magnetic inclination compass. Location-finding, or map, mechanisms have been more elusive. Visual landmarks, magnetic fields, odors, gravity and now also infrasound have been proposed as sources of information on location. Even in highly familiar locations, pigeons appear to neither use nor need landmarks and can even return to the loft while wearing frosted lenses. Direct and indirect evidence indicates magnetic field information influences pigeon navigation in ways that are consistent with magnetic map components. The role of odors is unclear; it might be motivational in nature rather than navigational. The influence of gravity must be further analyzed. Experiments with infrasound have been interpreted in the sense that they provide information on the home direction, but this hypothesis is inconsistent with the Map-and-Compass Model. All these factors appear to be components of a multifactorial system, with the pigeons being opportunistic, preferring those cues that prove most suitable in their home region. This has made understanding the roles of individual cues challenging. PMID:26149606

  20. Optimal Intermittent Reorientation in Insect Navigation

    Science.gov (United States)

    Peleg, Orit; Mahadevan, Lakshminarayanan; Applied Math Lab Team

    2015-03-01

    The process of navigation is often accompanied by several cognitive demanding activities, such as motor control, locomotion planning, and multi-sensory acquisition and integration. Organisms with limited cognitive resources must therefore multitask and develop optimal schemes to dynamically allocate resources to the different tasks. An extreme example of task alternations during navigation is the hallmark of ball rolling dung beetles. The beetles need to roll their dung-ball along a straight path away from the dung pile where intense competition occurs. Before initiating a roll, dung beetles climb on top of the ball and rotate about their vertical axis. This action serves as an orientation mechanism that allows them to set an initial bearing, and to regain this bearing if they experience an unintentional disturbance along the way. We developed a model inspired by the beetle's navigational scheme, where an agent performs a random walk intermittent by reorientation events, in which its heading direction is corrected. We show that the resultant paths are a characteristic of correlated diffusion in short time scale, and biased diffusion in the long time scale. We identify optimal alternation schemes and characterize their robustness upon introducing noisy sensory acquisition and rough environmental conditions.

  1. Geomagnetic storm effects on GPS based navigation

    Directory of Open Access Journals (Sweden)

    P. V. S. Rama Rao

    2009-05-01

    Full Text Available The energetic events on the sun, solar wind and subsequent effects on the Earth's geomagnetic field and upper atmosphere (ionosphere comprise space weather. Modern navigation systems that use radio-wave signals, reflecting from or propagating through the ionosphere as a means of determining range or distance, are vulnerable to a variety of effects that can degrade the performance of the navigational systems. In particular, the Global Positioning System (GPS that uses a constellation of earth orbiting satellites are affected due to the space weather phenomena.

    Studies made during two successive geomagnetic storms that occurred during the period from 8 to 12 November 2004, have clearly revealed the adverse affects on the GPS range delay as inferred from the Total Electron Content (TEC measurements made from a chain of seven dual frequency GPS receivers installed in the Indian sector. Significant increases in TEC at the Equatorial Ionization anomaly crest region are observed, resulting in increased range delay during the periods of the storm activity. Further, the storm time rapid changes occurring in TEC resulted in a number of phase slips in the GPS signal compared to those on quiet days. These phase slips often result in the loss of lock of the GPS receivers, similar to those that occur during strong(>10 dB L-band scintillation events, adversely affecting the GPS based navigation.

  2. Improving Independent Student Navigation of Complex Educational Web Sites: An Analysis of Two Navigation Design Changes in LibGuides

    OpenAIRE

    Pittsley, Kate A; Memmott, Sara

    2012-01-01

    Can the navigation of complex research web sites be improved so that users more often find their way without intermediation or instruction?  Librarians at Eastern Michigan University discovered that students were not recognizing navigational elements on web based research guides and tested possible solutions. In this study, two types of navigation improvements were applied to separate sets of online guides. Both sets of experimental guides showed an increase in use of navigation to secondary ...

  3. Free-segment Celestial Navigation of Ballistic Missile Based on the Stellar Refraction Measurement%基于星光跟踪器的弹道导弹自由段天文导航

    Institute of Scientific and Technical Information of China (English)

    李留建; 王明海

    2005-01-01

    研究了基于星光折射测量进行弹道导弹自由段导航的一种方法.这种导航方案利用高精度的CCD星敏感器,结合星光穿越大气的较精确的数学模型,来确定导弹质心位置的地心矢径.根据椭圆理论确定导弹自由段的轨道参数,进而进行导航、制导控制.

  4. 14 CFR 121.349 - Communication and navigation equipment for operations under VFR over routes not navigated by...

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Communication and navigation equipment for... § 121.349 Communication and navigation equipment for operations under VFR over routes not navigated by... receiver providing visual and aural signals; and (iii) One ILS receiver; and (3) Any RNAV system used...

  5. Cancer Patient Navigation Case Studies in Hawai‘i: The Complimentary Role of Clinical and Community Navigators

    OpenAIRE

    Domingo, Jermy B; Davis, Elise L; Allison, Amanda L; Braun, Kathryn L.

    2011-01-01

    This article describes the activities performed by cancer patient navigators in community-based and hospital settings. The case study demonstrates the depth and breadth of navigation activities and illustrates how hospital-based and community-based navigators work together to help individuals access cancer care and complete cancer treatment.

  6. Principles of X-ray Navigation

    Energy Technology Data Exchange (ETDEWEB)

    Hanson, John Eric; /SLAC

    2006-03-17

    X-ray navigation is a new concept in satellite navigation in which orientation, position and time are measured by observing stellar emissions in x-ray wavelengths. X-ray navigation offers the opportunity for a single instrument to be used to measure these parameters autonomously. Furthermore, this concept is not limited to missions in close proximity to the earth. X-ray navigation can be used on a variety of missions from satellites in low earth orbit to spacecraft on interplanetary missions. In 1997 the Unconventional Stellar Aspect Experiment (USA) will be launched as part of the Advanced Research and Global Observation Satellite (ARGOS). USA will provide the first platform for real-time experimentation in the field of x-ray navigation and also serves as an excellent case study for the design and manufacturing of space qualified systems in small, autonomous groups. Current techniques for determining the orientation of a satellite rely on observations of the earth, sun and stars in infrared, visible or ultraviolet wavelengths. It is possible to use x-ray imaging devices to provide arcsecond level measurement of attitude based on star patterns in the x-ray sky. This technique is explored with a simple simulation. Collimated x-ray detectors can be used on spinning satellites to provide a cheap and reliable measure of orientation. This is demonstrated using observations of the Crab Pulsar taken by the high Energy Astronomy Observatory (HEAO-1) in 1977. A single instrument concept is shown to be effective, but dependent on an a priori estimate of the guide star intensity and thus susceptible to errors in that estimate. A star scanner based on a differential measurement from two x-ray detectors eliminates the need for an a priori estimate of the guide star intensity. A first order model and a second order model of the two star scanner concepts are considered. Many of the stars that emit in the x-ray regime are also x-ray pulsars with frequency stability approaching a

  7. Integration of global poisoning system with internal navigation system

    International Nuclear Information System (INIS)

    The Global Positioning System (GPS), Inertial Navigation System (INS), and Integrated INS/GPS System are used in navigation. This project report gives the brief description of above three navigation techniques. The GPS system is a satellite based radio-navigation system that provides precise position, velocity and time information on land, at sea and in the air. On the other hand, the INS system determines the position by the double integration of the output of the accelerometers mounted on the gyroscopically stable platform. GPS system can augment INS system accuracy through Kalman filtering techniques. The integrated INS/GPS system is successfully applied in aerial navigation and missile guidance. (author)

  8. An integrated GPS/DR navigation system for AUV

    Institute of Scientific and Technical Information of China (English)

    PANG Yong-jie; SUN Yu-shan; GAN Yong; WAN Lei

    2006-01-01

    GPS/Dead-reckoning navigation system for autonomous underwater vehicle (AUV) is introduced, which includes navigation overall architecture, hardware and software structure.Dead-reckoning theory is presented in details. And the strong tracking Kalman filter and Singer model are applied to handle the imprecise navigation mode, which can improve the navigation system's precision and reliability. Finally, the sea experiments which include autonomous search mission in an unknown area and long distance motion are conducted to demonstrate the reliability and feasibility of the navigation system.

  9. Indoor inertial navigation application for smartphones with Android

    Science.gov (United States)

    Kamiński, Ł.; Tarapata, G.

    2015-09-01

    Inertial navigation is widely used by the military, in logistics and sailing. In mobile devices, inertial sensors are mostly used as a support for GPS and Wi-Fi-based navigation systems. Inertial-based navigation might prove useful on mobile devices running Android OS. At present, in spite of the accelerometer sensor's precision having been greatly improved, as well as the devices' computing power continuously rising, inertial navigation's precision still suffers. For smartphones, the key solution seems to be the usage of sensor fusion and signal smart filtering, both discussed in this paper. The paper also describes implementation of inertial navigation in Android devices, their analysis as well as test results.

  10. Navigation Performance of Global Navigation Satellite Systems in the Space Service Volume

    Science.gov (United States)

    Force, Dale A.

    2013-01-01

    GPS has been used for spacecraft navigation for many years center dot In support of this, the US has committed that future GPS satellites will continue to provide signals in the Space Service Volume center dot NASA is working with international agencies to obtain similar commitments from other providers center dot In support of this effort, I simulated multi-constellation navigation in the Space Service Volume In this presentation, I extend the work to examine the navigational benefits and drawbacks of the new constellations center dot A major benefit is the reduced geometric dilution of precision (GDOP). I show that there is a substantial reduction in GDOP by using all of the GNSS constellations center dot The increased number of GNSS satellites broadcasting does produce mutual interference, raising the noise floor. A near/far signal problem can also occur where a nearby satellite drowns out satellites that are far away. - In these simulations, no major effect was observed Typically, the use of multi-constellation GNSS navigation improves GDOP by a factor of two or more over GPS alone center dot In addition, at the higher altitudes, four satellite solutions can be obtained much more often center dot This show the value of having commitments to provide signals in the Space Service Volume Besides a commitment to provide a minimum signal in the Space Service Volume, detailed signal gain information is useful for mission planning center dot Knowledge of group and phase delay over the pattern would also reduce the navigational uncertainty

  11. Reference frames in learning from maps and navigation.

    Science.gov (United States)

    Meilinger, Tobias; Frankenstein, Julia; Watanabe, Katsumi; Bülthoff, Heinrich H; Hölscher, Christoph

    2015-11-01

    In everyday life, navigators often consult a map before they navigate to a destination (e.g., a hotel, a room, etc.). However, not much is known about how humans gain spatial knowledge from seeing a map and direct navigation together. In the present experiments, participants learned a simple multiple corridor space either from a map only, only from walking through the virtual environment, first from the map and then from navigation, or first from navigation and then from the map. Afterwards, they conducted a pointing task from multiple body orientations to infer the underlying reference frames. We constructed the learning experiences in a way such that map-only learning and navigation-only learning triggered spatial memory organized along different reference frame orientations. When learning from maps before and during navigation, participants employed a map- rather than a navigation-based reference frame in the subsequent pointing task. Consequently, maps caused the employment of a map-oriented reference frame found in memory for highly familiar urban environments ruling out explanations from environmental structure or north preference. When learning from navigation first and then from the map, the pattern of results reversed and participants employed a navigation-based reference frame. The priority of learning order suggests that despite considerable difference between map and navigation learning participants did not use the more salient or in general more useful information, but relied on the reference frame established first. PMID:25416007

  12. Biologically inspired autonomous agent navigation using an integrated polarization analyzing CMOS image sensor

    NARCIS (Netherlands)

    Sarkaer, M.; San Segundo Bello, D.; Van Hoof, C.; Theuwissen, A.

    2010-01-01

    The navigational strategies of insects using skylight polarization are interesting for applications in autonomous agent navigation because they rely on very little information for navigation. A polarization navigation sensor using the Stokes parameters to determine the orientation is presented. The

  13. Magnetic navigation versus mobile C-Arm

    International Nuclear Information System (INIS)

    The aim of this study was to demonstrate differences in radiation protection aspects between the use of a digital cardio angiography system with magnetic navigation (Artis Axiom dFcM + Stereotaxis NIOBE (registered) Magnetic Navigation System) and a standard mobile X-ray device with C-arm for electrophysiological procedures. Radiation exposure to staff and patients were analyzed and used for comparison. The time distribution of cardiology procedures for one physician is shown to introduce work of electrophysiology section. The records of procedures were used as information and as a data source for this study. These records include written operation as well as printed exam protocols. This study shows time course of procedures using the electro anatomical mapping system 'CARTO'. A single physicians performance has been used for this comparison to avoid possible differences between operators. The exposure time and air kerma product (PKA) values have been compared for both devices. Median value of exposure time, for each group of 20 patients, was reduced from 27.1 minutes to 20.0 minutes and radiation exposure from 12468 cGycm2 to 9078 cGycm2 PKA values. There is also scattered radiation in the operation area for C-Arm and the new technology presented. Magnetic navigation and replacing C-Arm by cardio angiography system reduces the personal dose by nearly one third, this fact was traced from personal monitoring reports. The main reason for saving time is the necessity to operate the catheter by joystick on a control panel from an adjacent room. These new technologies bring more effectiveness into interventional procedures, especially in cases of complicated examination, and reduce radiation exposure to patients and staff significantly. (author)

  14. 33 CFR 162.30 - Channel of Tuckerton Creek, N.J.; navigation.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Channel of Tuckerton Creek, N.J.; navigation. 162.30 Section 162.30 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY INLAND WATERWAYS NAVIGATION REGULATIONS § 162.30 Channel...

  15. 33 CFR 209.180 - Temporary closure of waterway to navigation.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Temporary closure of waterway to navigation. 209.180 Section 209.180 Navigation and Navigable Waters CORPS OF ENGINEERS, DEPARTMENT OF THE... navigation. (a) When an application is received for the temporary closure of a waterway for the...

  16. 33 CFR 162.35 - Channel of Christina River, Del.; navigation.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Channel of Christina River, Del.; navigation. 162.35 Section 162.35 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY INLAND WATERWAYS NAVIGATION REGULATIONS § 162.35 Channel...

  17. 33 CFR 207.580 - Buffalo Harbor, N.Y.; use, administration, and navigation.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Buffalo Harbor, N.Y.; use, administration, and navigation. 207.580 Section 207.580 Navigation and Navigable Waters CORPS OF ENGINEERS, DEPARTMENT OF THE ARMY, DEPARTMENT OF DEFENSE NAVIGATION REGULATIONS § 207.580 Buffalo Harbor, N.Y.;...

  18. Interaction Effects of Hypervideo Navigation Variables in College Students' Self-Regulated Learning

    Science.gov (United States)

    Azmy, Nabil

    2013-01-01

    The purpose of this study is to investigate the question of whether the interaction effects of hypervideo navigation variables (navigation control and navigation links) would affect college students' self-regulated learning just after their learning from instructional hypervideo programs. Navigation control (free navigation or free navigation with…

  19. Development of A Plant Navigation System

    International Nuclear Information System (INIS)

    A 'Plant Navigation System (PNS)' is under development to assist nuclear power plant (NPP) operators by automatically displaying the plant situation and plant operational procedures on a CRT screen when abnormalities occur. The operation procedures given in a symptom-oriented manual are expressed in a tree - type flowchart (modified PAD). The optimum operation procedure for an NPP is selected automatically using built-in diagnostic logics based on the current status of the NPP. Concerning the plant situation, the PNS displays important information only on the current status of the NPP. A prototype PNS system is being constructed. (authors)

  20. Calibration of vector navigation in desert ants.

    OpenAIRE

    Collett, M; Collett, T. S.; Wehner, R

    1999-01-01

    Desert ants (Cataglyphis sp.) monitor their position relative to the nest using a form of dead reckoning [1] [2] [3] known as path integration (PI) [4]. They do this with a sun compass and an odometer to update an accumulator that records their current position [1]. Ants can use PI to return to the nest [2] [3]. Here, we report that desert ants, like honeybees [5] and hamsters [6], can also use PI to approach a previously visited food source. To navigate to a goal using only PI information, a...

  1. Indoor Navigation using Direction Sensor and Beacons

    Science.gov (United States)

    Shields, Joel; Jeganathan, Muthu

    2004-01-01

    A system for indoor navigation of a mobile robot includes (1) modulated infrared beacons at known positions on the walls and ceiling of a room and (2) a cameralike sensor, comprising a wide-angle lens with a position-sensitive photodetector at the focal plane, mounted in a known position and orientation on the robot. The system also includes a computer running special-purpose software that processes the sensor readings to obtain the position and orientation of the robot in all six degrees of freedom in a coordinate system embedded in the room.

  2. Predictive Navigation by Understanding Human Motion Patterns

    Directory of Open Access Journals (Sweden)

    Shu-Yun Chung

    2011-03-01

    Full Text Available To make robots coexist and share the environments with humans, robots should understand the behaviors or the intentions of humans and further predict their motions. In this paper, an A*-based predictive motion planner is represented for navigation tasks. A generalized pedestrian motion model is proposed and trained by the statistical learning method. To deal with the uncertainty, a localization, tracking and prediction framework is also introduced. The corresponding recursive Bayesian formula represented as DBNs (Dynamic Bayesian Networks is derived for real time operation. Finally, the simulations and experiments are shown to validate the idea of this paper.

  3. Image matching navigation based on fuzzy information

    Institute of Scientific and Technical Information of China (English)

    田玉龙; 吴伟仁; 田金文; 柳健

    2003-01-01

    In conventional image matching methods, the image matching process is mostly based on image statistic information. One aspect neglected by all these methods is that there is much fuzzy information contained in these images. A new fuzzy matching algorithm based on fuzzy similarity for navigation is presented in this paper. Because the fuzzy theory is of the ability of making good description of the fuzzy information contained in images, the image matching method based on fuzzy similarity would look forward to producing good performance results. Experimental results using matching algorithm based on fuzzy information also demonstrate its reliability and practicability.

  4. Forecasting Social Navigation in Crowded Complex Scenes

    OpenAIRE

    Robicquet, Alexandre; Alahi, Alexandre; Sadeghian, Amir; Anenberg, Bryan; Doherty, John; Wu, Eli; Savarese, Silvio

    2016-01-01

    When humans navigate a crowed space such as a university campus or the sidewalks of a busy street, they follow common sense rules based on social etiquette. In this paper, we argue that in order to enable the design of new algorithms that can take fully advantage of these rules to better solve tasks such as target tracking or trajectory forecasting, we need to have access to better data in the first place. To that end, we contribute the very first large scale dataset (to the best of our knowl...

  5. Autonomous Rule Based Robot Navigation In Orchards

    DEFF Research Database (Denmark)

    Andersen, Jens Christian; Ravn, Ole; Andersen, Nils Axel

    2010-01-01

    Orchard navigation using sensor-based localization and exible mission management facilitates successful missions independent of the Global Positioning System (GPS). This is especially important while driving between tight tree rows where the GPS coverage is poor. This paper suggests localization ......, obstacle avoidance, path planning and drive control. The system is tested successfully using a Hako 20 kW tractor during autonomous missions in both cherry and apple orchards with mission length of up to 2.3 km including the headland turns....

  6. Orchard navigation using derivative free Kalman filtering

    DEFF Research Database (Denmark)

    Hansen, Søren; Bayramoglu, Enis; Andersen, Jens Christian;

    2011-01-01

    This paper describes the use of derivative free filters for mobile robot localization and navigation in an orchard. The localization algorithm fuses odometry and gyro measurements with line features representing the surrounding fruit trees of the orchard. The line features are created on basis of 2......D laser scanner data by a least square algorithm. The three derivative free filters are compared to an EKF based localization method on a typical run covering four rows in the orchard. The Matlab R toolbox Kalmtool is used for easy switching between different filter implementations without the need...

  7. ROBERT autonomous navigation robot with artificial vision

    International Nuclear Information System (INIS)

    This work, a joint research between ENEA (the Italian National Agency for Energy, New Technologies and the Environment) and DIGlTAL, presents the layout of the ROBERT project, ROBot with Environmental Recognizing Tools, under development in ENEA laboratories. This project aims at the development of an autonomous mobile vehicle able to navigate in a known indoor environment through the use of artificial vision. The general architecture of the robot is shown together with the data and control flow among the various subsystems. Also the inner structure of the latter complete with the functionalities are given in detail

  8. Autonomous underwater pipeline monitoring navigation system

    Science.gov (United States)

    Mitchell, Byrel; Mahmoudian, Nina; Meadows, Guy

    2014-06-01

    This paper details the development of an autonomous motion-control and navigation algorithm for an underwater autonomous vehicle, the Ocean Server IVER3, to track long linear features such as underwater pipelines. As part of this work, the Nonlinear and Autonomous Systems Laboratory (NAS Lab) developed an algorithm that utilizes inputs from the vehicles state of the art sensor package, which includes digital imaging, digital 3-D Sidescan Sonar, and Acoustic Doppler Current Profilers. The resulting algorithms should tolerate real-world waterway with episodic strong currents, low visibility, high sediment content, and a variety of small and large vessel traffic.

  9. Road vehicle navigation through virtual world simulation

    OpenAIRE

    Yung, NHC; Ye, C; Fong, FP

    1997-01-01

    In this paper, an integrated virtual world simulator for road vehicles and networks is presented. The structure of the simulator is modular and object-oriented, where the virtual world is hierarchically constructed. It supports 2D/3D real-time graphic rendering of objects which can be visualized on multiple X-windows, and a direct `plug-and-play' of algorithms written in C/C++. The simulator provides a test bed for automated driving, driving assistance, collision avoidance and navigation stra...

  10. Visual Navigation of an autonomous drone

    OpenAIRE

    Møst, Pål Moen

    2014-01-01

    In this thesis we have implemented and developed the necessary hardware and software solutions to transform a radio controlled quad copter into an autonomous drone. The main goal for this thesis was to safely land the drone by visual navigation on a given landing spot. To make this possible the we started with the assembly of a radio controlled quad copter from a almost-ready-to-fly kit (ARF) from AeroQuad. We then applied the necessary hardware to the drone by adding a web camera for visual ...

  11. Fiber optic gyroscopes for vehicle navigation systems

    Science.gov (United States)

    Kumagai, Tatsuya; Soekawa, Hirokazu; Yuhara, Toshiya; Kajioka, Hiroshi; Oho, Shigeru; Sonobe, Hisao

    1994-03-01

    Fiber optic gyroscopes (FOGs) have been developed for vehicle navigation systems and are used in Toyota Motor Corporation models Mark II, Chaser and Cresta in Japan. Use of FOGs in these systems requires high reliability under a wide range of conditions, especially in a temperature range between -40 and 85 degree(s)C. In addition, a high cost-performance ratio is needed. We have developed optical and electrical systems that are inexpensive and can perform well. They are ready to be mass-produced. FOGs have already been installed in luxury automobiles, and will soon be included in more basic vehicles. We have developed more inexpensive FOGs for this purpose.

  12. Navigation, immersion og interaktion i videoinstallationen

    DEFF Research Database (Denmark)

    Petersen, Anne Ring

    2008-01-01

    Artiklen diskuterer, hvilken rolle videoinstallationen har spillet i de seneste årtiers radikale receptionsæstetiske omstillinger inden for samtidskunsten i almindelighed og installationskunsten i særdeleshed. I fokus for diskussionen står beskuerens krop og spørgsmålet om på hvilke måder videoin...... receptionsformer lige fra genrens undfangelse i 1960’erne. I forlængelse heraf påvises det, at videoinstallationer kan invitere til en vifte af forskellige receptionsformer, hvoraf artiklen særligt koncentrerer sig om at redegøre for tre: navigation, immersion og interaktion....

  13. Another point of view on proportional navigation

    Directory of Open Access Journals (Sweden)

    E. Duflos

    1998-01-01

    Full Text Available Proportional navigation is one of the most popular and one of the most used of the guidance laws. But the way it is studied is always the same: the acceleration needed to reach a known target is derived or analyzed. This way of studying guidance laws is called “the direct problem” by the authors. On the contrary, the problem considered here is to find, from the knowledge of a part of the trajectory of a maneuvering object, the target of this object. The authors call this way of studying guidance laws “the inverse problem”.

  14. A Novel Dynamic Physical Storage Model for Vehicle Navigation Maps

    Directory of Open Access Journals (Sweden)

    Shaohua Wang

    2016-04-01

    Full Text Available The physical storage model is one of the key technologies for vehicle navigation maps used in a navigation system. However, the performance of most traditional storage models is limited in dynamic navigation due to the static storage format they use. In this paper, we proposed a new physical storage model, China Navigation Data Format (CNDF, which helped access and update the navigation data. The CNDF model used the reach-based hierarchy method to build a road hierarchal network, which enhanced the efficiency of data compression. It also adopted the Linear Link Coding method, in which the start position was combined with the end position as the identification code for multi-level links, and each link traced up-level links consistently without recording the array of identifications. The navigation map of East China (including Beijing, Tianjin, Shandong, Hebei, and Jiangsu at 1:10,000, generated using the CNDF model, and the real time traffic information in Beijing were combined to test the performance of a navigation system using an embedded navigation device. Results showed that it cost less than 1 second each time to refresh the navigation map, and the accuracy of the hierarchal shortest-path algorithm was 99.9%. Our work implied that the CNDF model is efficient in vehicle navigation applications.

  15. Olfaction, navigation, and the origin of isocortex

    Science.gov (United States)

    Aboitiz, Francisco; Montiel, Juan F.

    2015-01-01

    There are remarkable similarities between the brains of mammals and birds in terms of microcircuit architecture, despite obvious differences in gross morphology and development. While in reptiles and birds the most expanding component (the dorsal ventricular ridge) displays an overall nuclear shape and derives from the lateral and ventral pallium, in mammals a dorsal pallial, six-layered isocortex shows the most remarkable elaboration. Regardless of discussions about possible homologies between mammalian and avian brains, a main question remains in explaining the emergence of the mammalian isocortex, because it represents a unique phenotype across amniotes. In this article, we propose that the origin of the isocortex was driven by behavioral adaptations involving olfactory driven goal-directed and navigating behaviors. These adaptations were linked with increasing sensory development, which provided selective pressure for the expansion of the dorsal pallium. The latter appeared as an interface in olfactory-hippocampal networks, contributing somatosensory information for navigating behavior. Sensory input from other modalities like vision and audition were subsequently recruited into this expanding region, contributing to multimodal associative networks. PMID:26578863

  16. Navigating mazes in a virtual environment

    Science.gov (United States)

    Browse, Roger A.; Skillicorn, David B.; Middleman, Darren

    2003-06-01

    In this research we are concerned with computer interfaces with which subjects navigate through maze simulations which are essentially buildings, with corridors and intersections, such as frequently encountered in computer games and simulations. We wish to determine if virtual reality interfaces introduce a performance enhancement that might be expected for display configurations which mimic natural perceptual experiences. We have experimented primarily with two display conditions for presentation of and navigation through the mazes. Subjects either view the maze on a desktop computer monitor, turning and moving within the maze with the mouse in a way that is similar to the configurations used in most first-person role playing computer games, or they viewed the maze from a standing position with a head-mounted display, being free to direct the view of the maze through body and head movements, and using the depression of a mouse button to effect movement in the direction that they were facing. Head-tracking was required for this latter condition. As expected there are striking individual differences in subjects" abilities to learn to traverse the mazes. Across a variety of maze configuration parameters which significantly do influence performance, the results indicate that the virtual reality enhancements have no effect subjects' ability to learn the mazes, either as route knowledge or as cognitive maps.

  17. Interplanetary navigation or the cosmic flipper

    Science.gov (United States)

    Tien Khang, U.

    1983-04-01

    Various navigational factors involved in guidance of an asteroid mineral survey probe if launched on the Ariane 4 are considered. Any flyby of an asteroid will be subject to solar gravity, the velocity of the probe relative to the sun and the asteroid, and the orbit and the velocity of the asteroid relative to the sun. Use of a gravity assist by the earth or Mars is a way to gain added inertial forces, therefore the 'cosmic flipper' effect; more asteroid groups can be visited in this manner. The navigational coordinates must be plotted in a heliocentric coordinate system to account for the sun's gravitational sphere of influence. Candidate asteroid groups which can be visited were studied using the travelling salesman problem, which generated astronomical numbers of possible trajectories. Considering a minimal distance and maximum number of asteroids, a total of 14,000 missions were identified. A mission to survey the asteroid Ceres in 1987 with a 400 kg instrument payload is recommended.

  18. Basal ganglia contributions to adaptive navigation.

    Science.gov (United States)

    Mizumori, Sheri J Y; Puryear, Corey B; Martig, Adria K

    2009-04-12

    The striatum has long been considered to be selectively important for nondeclarative, procedural types of memory. This stands in contrast with spatial context processing that is typically attributed to hippocampus. Neurophysiological evidence from studies of the neural mechanisms of adaptive navigation reveals that distinct neural systems such as the striatum and hippocampus continuously process task relevant information regardless of the current cognitive strategy. For example, both striatal and hippocampal neural representations reflect spatial location, directional heading, reward, and egocentric movement features of a test situation in an experience-dependent way, and independent of task demands. Thus, continual parallel processing across memory systems may be the norm rather than the exception. It is suggested that neuromodulators, such as dopamine, may serve to differentially regulate learning-induced neural plasticity mechanisms within these memory systems such that the most successful form of neural processing exerts the strongest control over response selection functions. In this way, dopamine may serve to optimize behavioral choices in the face of changing environmental demands during navigation. PMID:19056429

  19. Olfaction, navigation, and the origin of isocortex.

    Science.gov (United States)

    Aboitiz, Francisco; Montiel, Juan F

    2015-01-01

    There are remarkable similarities between the brains of mammals and birds in terms of microcircuit architecture, despite obvious differences in gross morphology and development. While in reptiles and birds the most expanding component (the dorsal ventricular ridge) displays an overall nuclear shape and derives from the lateral and ventral pallium, in mammals a dorsal pallial, six-layered isocortex shows the most remarkable elaboration. Regardless of discussions about possible homologies between mammalian and avian brains, a main question remains in explaining the emergence of the mammalian isocortex, because it represents a unique phenotype across amniotes. In this article, we propose that the origin of the isocortex was driven by behavioral adaptations involving olfactory driven goal-directed and navigating behaviors. These adaptations were linked with increasing sensory development, which provided selective pressure for the expansion of the dorsal pallium. The latter appeared as an interface in olfactory-hippocampal networks, contributing somatosensory information for navigating behavior. Sensory input from other modalities like vision and audition were subsequently recruited into this expanding region, contributing to multimodal associative networks. PMID:26578863

  20. Structure and navigation for electronic publishing

    Science.gov (United States)

    Tillinghast, John; Beretta, Giordano B.

    1998-01-01

    The sudden explosion of the World Wide Web as a new publication medium has given a dramatic boost to the electronic publishing industry, which previously was a limited market centered around CD-ROMs and on-line databases. While the phenomenon has parallels to the advent of the tabloid press in the middle of last century, the electronic nature of the medium brings with it the typical characteristic of 4th wave media, namely the acceleration in its propagation speed and the volume of information. Consequently, e-publications are even flatter than print media; Shakespeare's Romeo and Juliet share the same computer screen with a home-made plagiarized copy of Deep Throat. The most touted tool for locating useful information on the World Wide Web is the search engine. However, due to the medium's flatness, sought information is drowned in a sea of useless information. A better solution is to build tools that allow authors to structure information so that it can easily be navigated. We experimented with the use of ontologies as a tool to formulate structures for information about a specific topic, so that related concepts are placed in adjacent locations and can easily be navigated using simple and ergonomic user models. We describe our effort in building a World Wide Web based photo album that is shared among a small network of people.

  1. Visual measurement estimation for autonomous vehicle navigation

    Science.gov (United States)

    Campos, Mario F.; Chaimowicz, Luiz

    1999-07-01

    The autonomous navigation of a mobile vehicle can be described as the task it undertakes to move itself in the environment through a series of positions based on information based on information gathered by its sensors. In order to accomplish this task, the vehicle has to cope with two main subtasks namely obstacle avoidance and self localization. The latter implies in the ability to determine its position and orientation with respect to the environment. This work describes a simple but efficient method that performs pose estimation for a mobile vehicle based on visual information from artificial landmarks using a sequence of frames from an uncalibrated camera. The landmark is segmented from image sequences and the vehicle's localization is computed using landmark geometric properties and vehicle's motion vector. This methodology can be easily extended to be used by different types of mobile agents. One of the key advantages is that it is computationally, efficient making it suitable for real time navigation. Experiments conducted with a Nomad 200 mobile robot equipped with a color camera systems have shown the method to be repeatable and very robust to noise. Visual measurements were compared with readings for other on-board sensors such as ultrasound with excellent consistency.

  2. The European Satellite Navigation System Galileo

    Institute of Scientific and Technical Information of China (English)

    G.W. Hein; T. Pany

    2003-01-01

    This paper starts with a brief discussion of the Galileo project status and with a description of the present Galileo architecture (space segment, ground segment, user segment). It focuses on explaining special features compared to the American GPS system. The presentation of the user segment comprises a discussion of the actual Galileo signal structure. The Galileo carrier frequency, modulation scheme and data rate of all 10 navigation signals are described as well as parameters of the search and rescue service. The navigation signals are used to realize three types of open services, the safety of life service, two types of commercial services and the public regulated service. The signal performance in terms of the pseudorange code error due to thermal noise and multipath is discussed as well as interference to and from other radionavigation services broadcasting in the E5 and E6 frequency band. The interoperability and compatibility of Galileo and GPS is realized by a properly chosen signal structures in E5a/L5 and E2-L1-E1 and compatible geodetic and time reference frames. Some new results on reciprocal GPS/Galileo signal degradation due to signal overlay are presented as well as basic requirements on the Galileo code sequences.

  3. Herschel celestial calibration sources: Four large main-belt asteroids as prime flux calibrators for the far-IR/sub-mm range

    CERN Document Server

    Mueller, T G; Nielbock, M; Lim, T; Teyssier, D; Olberg, M; Klaas, U; Linz, H; Altieri, B; Pearson, C; Bendo, G; Vilenius, E

    2013-01-01

    Celestial standards play a major role in observational astrophysics. They are needed to characterise the performance of instruments and are paramount for photometric calibration. During the Herschel Calibration Asteroid Preparatory Programme approximately 50 asteroids have been established as far-IR/sub-mm/mm calibrators for Herschel. The selected asteroids fill the flux gap between the sub-mm/mm calibrators Mars, Uranus and Neptune, and the mid-IR bright calibration stars. All three Herschel instruments observed asteroids for various calibration purposes, including pointing tests, absolute flux calibration, relative spectral response function, observing mode validation, and cross-calibration aspects. Here we present newly established models for the four large and well characterized main-belt asteroids (1) Ceres, (2) Pallas, (4) Vesta, and (21) Lutetia which can be considered as new prime flux calibrators. The relevant object-specific properties (size, shape, spin-properties, albedo, thermal properties) are w...

  4. Development of a GPS/INS/MAG navigation system and waypoint navigator for a VTOL UAV

    Science.gov (United States)

    Meister, Oliver; Mönikes, Ralf; Wendel, Jan; Frietsch, Natalie; Schlaile, Christian; Trommer, Gert F.

    2007-04-01

    Unmanned aerial vehicles (UAV) can be used for versatile surveillance and reconnaissance missions. If a UAV is capable of flying automatically on a predefined path the range of possible applications is widened significantly. This paper addresses the development of the integrated GPS/INS/MAG navigation system and a waypoint navigator for a small vertical take-off and landing (VTOL) unmanned four-rotor helicopter with a take-off weight below 1 kg. The core of the navigation system consists of low cost inertial sensors which are continuously aided with GPS, magnetometer compass, and a barometric height information. Due to the fact, that the yaw angle becomes unobservable during hovering flight, the integration with a magnetic compass is mandatory. This integration must be robust with respect to errors caused by the terrestrial magnetic field deviation and interferences from surrounding electronic devices as well as ferrite metals. The described integration concept with a Kalman filter overcomes the problem that erroneous magnetic measurements yield to an attitude error in the roll and pitch axis. The algorithm provides long-term stable navigation information even during GPS outages which is mandatory for the flight control of the UAV. In the second part of the paper the guidance algorithms are discussed in detail. These algorithms allow the UAV to operate in a semi-autonomous mode position hold as well an complete autonomous waypoint mode. In the position hold mode the helicopter maintains its position regardless of wind disturbances which ease the pilot job during hold-and-stare missions. The autonomous waypoint navigator enable the flight outside the range of vision and beyond the range of the radio link. Flight test results of the implemented modes of operation are shown.

  5. A fuzzy logic based navigation for mobile robot

    International Nuclear Information System (INIS)

    The main issue of intelligent robot is how to reach its goal safely in real time when it moves in unknown environment. The navigational planning is becoming the central issue in development of real-time autonomous mobile robots. Behaviour based robots have been successful in reacting with dynamic environment but still there are some complexity and challenging problems. Fuzzy based behaviours present as powerful method to solve the real time reactive navigation problems in unknown environment. We shall classify the navigation generation methods, five some characteristics of these methods, explain why fuzzy logic is suitable for the navigation of mobile robot and automated guided vehicle, and describe a reactive navigation that is flexible to react through their behaviours to the change of the environment. Some simulation results will be presented to show the navigation of the robot. (Author)

  6. Basal electric and magnetic fields of celestial bodies come from positive-negative charge separation caused by gravitation of quasi-Casimir pressure in weak interaction

    Science.gov (United States)

    Chen, Shao-Guang

    falling and till reach the equilibrium of stable spatial charge distribution, which is just the cause of the geomagnetic field and the geo-electric field (the observational value on the earth surface is about 120 V/m downward equivalent to 500000 Coulomb negative charges in the earth surface). All celestial bodies are gravitation sources and attract the molecules and ions in space to its circumference by the gravitation of own and other celestial bodies, e.g., all planets in the solar system have their own atmospheres. Therefore, the origin mechanism of geo-electric and geomagnetic fields caused by gravitation is very universal, at least it is appli-cable to all the planets in the solar system. For planets, the joint result of the gravitations of the planets and the sun makes the negative charges and dipolar charges distributed in the surfaces of the celestial bodies. The quicker the rotation is, the larger the angular momentum U is, then larger the accompanying current and magnetic moment P, it accord a experiential law found by subsistent observational data of all celestial bodies in solar system: P = -G 1/2 U cos θ / c (1), θ is the angle between the net ν 0 flux direction (mark by CMB) and the rotational axis of celestial body (Chen Shao-Guang, Chinese Science Bulletin, 26,233,1981). Uranian and Neptunian P predicted with Eq.(1) in 1981 are about -3.4•1028 Gs•cm3 and 1.9•1028 Gs•cm3 respectively (use new rotate speed measured by Voyager 2). The P measured by Voyager 2 in 1986 and 1989 are about -1.9 •1028 Gs•cm3 and 1.5•1028 Gs•cm3 respectively (the contribution of quadrupole P is converted into the contribution of dipole P alone). The neutron star pos-sesses much high density and rotational speed because of the conservation of the mass and the angular momentum during the course of the formation, then has strong gravity and largerU. From Eq.(1) there is a larger P and extremely strong surface magnetic field in neutron star. The origin mechanism of

  7. Optical Navigation Preparations for New Horizons Pluto Flyby

    Science.gov (United States)

    Owen, William M., Jr.; Dumont, Philip J.; Jackman, Coralie D.

    2012-01-01

    The New Horizons spacecraft will encounter Pluto and its satellites in July 2015. As was the case for the Voyager encounters with Jupiter, Saturn, Uranus and Neptune, mission success will depend heavily on accurate spacecraft navigation, and accurate navigation will be impossible without the use of pictures of the Pluto system taken by the onboard cameras. We describe the preparations made by the New Horizons optical navigators: picture planning, image processing algorithms, software development and testing, and results from in-flight imaging.

  8. Error Analysis of Inertial Navigation Systems Using Test Algorithms

    OpenAIRE

    Vaispacher, Tomáš; Bréda, Róbert; Adamčík, František

    2015-01-01

    Content of this contribution is an issue of inertial sensors errors, specification of inertial measurement units and generating of test signals for Inertial Navigation System (INS). Given the different levels of navigation tasks, part of this contribution is comparison of the actual types of Inertial Measurement Units. Considering this comparison, there is proposed the way of solving inertial sensors errors and their modelling for low – cost inertial navigation applications. The last part is ...

  9. Optimal switching strategies for stochastic geocentric/egocentric navigation

    OpenAIRE

    Peleg, O.; Mahadevan, L.

    2015-01-01

    Animals use a combination of egocentric navigation driven by the internal integration of environmental cues, interspersed with geocentric course correction and reorientation, often with uncertainty in sensory acquisition of information, planning and execution. Inspired directly by observations of dung beetle navigational strategies that show switching between geocentric and egocentric strategies, we consider the question of optimal strategies for the navigation of an agent along a preferred d...

  10. The SmartVision navigation prototype for the blind

    OpenAIRE

    du Buf, J. M. H.; Barroso, João; J.M.F. Rodrigues; Paredes, Hugo; Farrajota, Miguel; Fernandes, Hugo; José, João; Teixeira, Victor; Saleiro, Mário

    2010-01-01

    The goal of the project "SmartVision: active vision for the blind" is to develop a small and portable but intelligent and reliable system for assisting the blind and visually impaired while navigating autonomously, both outdoor and indoor. In this paper we present an overview of the prototype, design issues, and its different modules which integrate a GIS with GPS, Wi-Fi, RFID tags and computer vision. The prototype addresses global navigation by following known landmarks, local navigation wi...

  11. Vision-based absolute navigation for the Martian landing

    OpenAIRE

    Martínez Torío, Alexandra

    2013-01-01

    Future European missions aspire to bring soil samples from Mars back to Earth. The precise identification of the site from which samples are taken leads to major constraints as to the landing accuracy of the lander. Vision-based absolute navigation now appears to be the most promising navigation method for correcting errors originated from the interplanetary voyage at the point of re-entry. The thesis has consisted in improving the vision-based absolute navigation simulator developed for the ...

  12. Information measures and cognitive limits in multilayer navigation

    OpenAIRE

    Gallotti, Riccardo; Porter, Mason A.; Barthelemy, Marc

    2015-01-01

    Cities and their transportation systems become increasingly complex and multimodal as they grow, and it is natural to wonder if it is possible to quantitatively characterize our difficulty to navigate in them and whether such navigation exceeds our cognitive limits. A transition between different searching strategies for navigating in metropolitan maps has been observed for large, complex metropolitan networks. This evidence suggests the existence of another limit associated to the cognitive ...

  13. Sensor-based navigation applied to intelligent electric vehicles

    OpenAIRE

    Alves De Lima, Danilo

    2015-01-01

    Autonomous navigation of car-like robots is a large domain with several techniques and applications working in cooperation. It ranges from low-level control to global navigation, passing by environment perception, robot localization, and many others in asensor-based approach. Although there are very advanced works, they still presenting problems and limitations related to the environment where the car is inserted and the sensors used. This work addresses the navigation problem of car-like rob...

  14. Cancer Patient Navigator Tasks across the Cancer Care Continuum

    OpenAIRE

    Braun, Kathryn L; Kagawa-Singer, Marjorie; Holden, Alan E. C.; Burhansstipanov, Linda; Tran, Jacqueline H.; Seals, Brenda F.; Corbie-Smith, Giselle; Tsark, JoAnn U.; Harjo, Lisa; Foo, Mary Anne; Ramirez, Amelie G.

    2012-01-01

    Cancer patient navigation (PN) programs have been shown to increase access to and utilization of cancer care for poor and underserved individuals. Despite mounting evidence of its value, cancer patient navigation is not universally understood or provided. We describe five PN programs and the range of tasks their navigators provide across the cancer care continuum (education and outreach, screening, diagnosis and staging, treatment, survivorship, and end-of-life). Tasks are organized by their ...

  15. Software framework for off-road autonomous robot navigation system

    Institute of Scientific and Technical Information of China (English)

    WU Er-yong; ZHOU Wen-hui; ZHANG Li; DAI Guo-jun

    2009-01-01

    This paper presents a software framework for off-road autonomous robot navigation system. With the requirements of accurate terrain perception and instantaneous obstacles detection, one navigation software framework was advanced based on the principles of "three layer architecture" of intelligence system. Utilized the technologies of distributed system, machine learning and multiple sensor fusion, individual functional module was discussed. This paper aims to provide a framework reference for autonomous robot navigation system design.

  16. A Bionic Camera-Based Polarization Navigation Sensor

    OpenAIRE

    Daobin Wang; Huawei Liang; Hui Zhu; Shuai Zhang

    2014-01-01

    Navigation and positioning technology is closely related to our routine life activities, from travel to aerospace. Recently it has been found that Cataglyphis (a kind of desert ant) is able to detect the polarization direction of skylight and navigate according to this information. This paper presents a real-time bionic camera-based polarization navigation sensor. This sensor has two work modes: one is a single-point measurement mode and the other is a multi-point measurement mode. An indoor ...

  17. Navigation systems for approach and landing of VTOL aircraft

    Science.gov (United States)

    Schmidt, S. F.; Mohr, R. L.

    1979-01-01

    The formulation and implementation of navigation systems used for research investigations in the V/STOLAND avionics system are described. The navigation systems prove position and velocity in a cartestian reference frame aligned with the runway. They use filtering techniques to combine the raw position data from navaids (e.g., TACAN, MLS) with data from onboard inertial sensors. The filtering techniques which use both complementary and Kalman filters, are described. The software for the navigation systems is also described.

  18. External Navigation Control and Guidance for Learning with Spatial Hypermedia

    OpenAIRE

    Verhoeven, Antoon; Warendorf, Kai

    1999-01-01

    Abstract: The World Wide Web has become a widely available platform for learning with hypermedia. However, WWW hypermedia is often limited in both guidance and navigation support. To improve hypermedia in these aspects, we propose a spatial hypermedia browser for educational purposes. A prototype browser, named HyperMap, has been designed to integrate guided explorative browsing with external control over a learnerís navigation. The flexible control by authors over navigation allows the inte...

  19. Using landmarks to support older people in navigation

    OpenAIRE

    Goodman, J.; Gray, P.D.G.; Khammampad, K.; Brewster, S.

    2004-01-01

    Although landmarks are an integral aspect of navigation, they have rarely been used within electronic navigation aids. This paper describes the design of a pedestrian navigation aid for a handheld computer, which guides the user along a route using photographs of landmarks, together with audio and text instructions that reference these landmarks. This aid was designed with older users in mind who often find their mobility hampered by declines in sensory, cognitive and motor abilities. It was ...

  20. A Low-Cost, High-Precision Navigator Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Toyon Research Corporation proposes to develop and demonstrate a prototype low-cost precision navigation system using commercial-grade gyroscopes and...