Sample records for gyrocompasses

  1. A Gyrocompass for Maritime Applications Based Upon Multivariable Control Theory

    Olav Egeland


    Full Text Available A gyrocompass is designed using multivariable control theory. The compass can be implemented with an inertial platform or as a strap-down system. Measurement noise caused by vessel acceleration is modeled and feedforward is taken from vessel speed. Though the model is of order 9, it has only three unknown parameters of which one can be chosen a priori. Parameter estimation is discussed. For simulation of the compass, a non-linear surface vessel model with 6 degrees of freedom and wave excitation is used.

  2. Error Analysis and Compensation of Gyrocompass Alignment for SINS on Moving Base

    Bo Xu


    Full Text Available An improved method of gyrocompass alignment for strap-down inertial navigation system (SINS on moving base assisted with Doppler velocity log (DVL is proposed in this paper. After analyzing the classical gyrocompass alignment principle on static base, implementation of compass alignment on moving base is given in detail. Furthermore, based on analysis of velocity error, latitude error, and acceleration error on moving base, two improvements are introduced to ensure alignment accuracy and speed: (1 the system parameters are redesigned to decrease the acceleration interference and (2 a data repeated calculation algorithm is used in order to shorten the prolonged alignment time caused by changes in parameters. Simulation and test results indicate that the improved method can realize the alignment on moving base quickly and effectively.


    Gennady I. Emelyantsev


    Full Text Available The paper presents operation algorithms of ESG-based strapdown stabilized gyrocompass (SSGC located onboard a mobile vehicle. Initial alignment mode and calibration of drift model coefficients onboard a vehicle is aided by reference attitude (heading, pitch and roll angles and position data. The required reference attitude parameters can be generated by joint processing of data from MEMS IMU with gyros and accelerometers and GPS compass. Depending on the vehicle dynamics and required accuracy of generated heading, the system may use IMU based on the fiber-optic gyros and accelerometers instead of MEMS to construct the place vertical. Specific features of SSGC algorithms in heading generation are considered. Calibration and corrected operation modes of the system are described. The SSGC uses two ESGs with orthogonal angular momentum vectors, where one gyro is the reference (unit vector of its angular momentum is aligned with the celestial axis and the other one is virtual (with zero misalignments with respect to the inertial frame, and zero drift model coefficients. Joint processing of SSGC data and external position aiding is realized by extended Kalman filter with full-state feedback control. Simulation modeling results of the system operation algorithms are presented. Simulation modeling has confirmed the system compass effect and determined the time required for calibration of ESG with solid-rotor. The results have been applied at «Concern CSRI “Elektropribor”», JSC

  4. Using a MEMS gyroscope to measure the Earth’s rotation for gyrocompassing applications

    Iozan, L. I.; Kirkko-Jaakkola, M.; Collin, J.; Takala, J.; Rusu, C.


    In this paper, a method and system for gyrocompassing based on a low-cost micro-electro-mechanical (MEMS) gyroscope are described. The proposed setup is based on the choice of a gyroscope with specified bias instability better than 2 deg h-1 and on careful error compensation. The gyroscope is aligned parallel to the local level, which helps to eliminate the g-sensitivity effect but also sacrifices a fraction of the Earth’s rotation rate that can be observed. The additive bias is compensated for by rotating the sensor mechanically and by extended Kalman filtering. In this paper, it is demonstrated that the proposed system is capable of observing the Earth’s rotation, and the north finding results show that a two-sigma accuracy of 4.03° was attained at latitude 61°N. With current MEMS gyroscopes, the system requires hours of time to achieve this accuracy, but the results demonstrate the theoretical accuracy potential of these small self-contained, low-cost sensors.

  5. An Adaptive Damping Network Designed for Strapdown Fiber Optic Gyrocompass System for Ships

    Jin Sun


    Full Text Available The strapdown fiber optic gyrocompass (strapdown FOGC system for ships primarily works on external horizontal damping and undamping statuses. When there are large sea condition changes, the system will switch frequently between the external horizontal damping status and the undamping status. This means that the system is always in an adjustment status and influences the dynamic accuracy of the system. Aiming at the limitations of the conventional damping method, a new design idea is proposed, where the adaptive control method is used to design the horizontal damping network of the strapdown FOGC system. According to the size of acceleration, the parameters of the damping network are changed to make the system error caused by the ship’s maneuvering to a minimum. Furthermore, the jump in damping coefficient was transformed into gradual change to make a smooth system status switch. The adaptive damping network was applied for strapdown FOGC under the static and dynamic condition, and its performance was compared with the conventional damping, and undamping means. Experimental results showed that the adaptive damping network was effective in improving the dynamic performance of the strapdown FOGC.

  6. Development of a Self-Calibrated MEMS Gyrocompass for North-Finding and Tracking

    Prikhodko, Igor P.

    This Ph.D. dissertation presents development of a microelectromechanical (MEMS) gyrocompass for north-finding and north-tracking applications. The central part of this work enabling these applications is control and self-calibration architectures for drift mitigation over thermal environments, validated using a MEMS quadruple mass gyroscope. The thesis contributions are the following: • Adapted and implemented bias and scale-factor drifts compensation algorithm relying on temperature self-sensing for MEMS gyroscopes with high quality factors. The real-time self-compensation reduced a total bias error to 2 °/hr and a scale-factor error to 500 ppm over temperature range of 25 °C to 55 °C (on par with the state-of-the-art). • Adapted and implemented a scale-factor self-calibration algorithm previously employed for macroscale hemispherical resonator gyroscope to MEMS Coriolis vibratory gyroscopes. An accuracy of 100 ppm was demonstrated by simultaneously measuring the true and estimated scale-factors over temperature variations (on par with the state-of-the art). • Demonstrated north-finding accuracy satisfying a typical mission requirement of 4 meter target location error at 1 kilometer stand-off distance (on par with a GPS accuracy). Analyzed north-finding mechanizations trade-offs for MEMS vibratory gyroscopes and demonstrated measurements of the Earth's rotation (15 °/hr). • Demonstrated, for the first time, an angle measuring MEMS gyroscope operation for north-tracking applications in a +/-500 °/s rate range and 100 Hz bandwidth, eliminating both bandwidth and range constraints of conventional open-loop Coriolis vibratory gyroscopes. • Investigated hypothesis that surface-tension driven glass-blowing microfabrication can create highly spherical shells for 3-D MEMS. Without any trimming or tuning of the natural frequencies, a 1 MHz glass-blown 3-D microshell resonator demonstrated a 0.63 % frequency mismatch between two degenerate 4-node wineglass

  7. 航向大失准角下的罗经法对准研究%Research of gyro-compassing alignment for large azimuth misalignment

    郝燕玲; 张义; 孙枫


    船舶在系泊状态下由于风浪和浪涌的干扰,常会致使捷联惯导系统航向粗对准的精度达不到精对准的要求.为了能够使惯导系统在此种情况下也可以快速的完成精确对准,文中首先分析了罗经法对准在航向失准角大的情况下所受的影响,随后对解决该问题的方法进行了研究,深入分析了该系统在对准过程中参数变化的影响形式,最终提出了一种基于时变参数的罗经法对准方案.仿真和实验的结果表明,与传统的罗经法对准相比,使用这种基于时变参数的罗经法对准在航向大失准角的情况下也能够快速的完成精确对准.%As ships may be disturbed by stormy waves in mooring status, the accuracy of SINS azimuth coarse alignment may not be high enough for fine alignment. Aiming at this problem, the influence of large azimuth misalignment angle on gyro-compassing alignment is studied. Then, the solution to the problem is discussed, and the influence of gyro-compassing parameter change is analyzed. Finally, a gyro-compassing alignment method on the basis of time-varying parameters is described. Simulation and experimental results show that, compared with traditional gyro-compass alignment method, this time-varying parameter alignment method is faster in alignment speed and more accurate in precision in the case of large heading uncertainty.

  8. 捷联惯导系统罗经对准仿真研究%Simulation and research on gyrocompass alignment of SINS

    郜福全; 陈丽容; 丁传红; 刘建锋


    The thoery foundation and control diagram of traditional platform inertial navigation system is introduced. On this basis , the idea of PINS compass alignment is applied to the alignment of SINS. Gyrocompass alignment of SINS is investigatd. The the control parameter's formula and theortical alignment errors is given. The contious system model is structed. Due to the reality that in real system design, gyrocompass can only be applied to system via the serial execuation of program, the contius system model is discreted, move forward a step, the discrete control system is transform to equivalent program. Simuliation results show that alignment of SINS by gyrocompass is effective, the theortical error and simulation result's error is consistent, and the three way of SINS gyrocompass alignment realation is equivalent.%分析了传统的平台式惯导的理论基础、给出了控制框图,在此基础上,将平台罗经对准的思想应用到捷联惯导系统的罗经对准,研究了捷联式惯导系统罗经自对准技术,给出了根据捷联罗经对准的指标求罗经控制参数的公式和罗经对准的理论对准误差,建立捷联罗经对准的连续控制系统模型,并将该连续控制系统的模型离散化,得到捷联惯导系统罗经对准的离散控制系统模型,由于实际应用中,罗经对准只能通过程序的形式串行实现,将捷联惯导系统罗经对准的离散控制系统模型转化为等效的程序实现.通过对连续控制系统、离散系统和等价的串行程序3种实现方式进行仿真,仿真结果表明了捷联惯导罗经对准的有效性,罗经对准实际误差和理论误差的一致性,以及3种对准方式的等价性.

  9. Active disturbance rejection control technique to gyrocompass alignment of SINS%基于自抗扰控制技术的捷联罗经对准算法

    周琪; 杨鹏翔; 秦永元


    在大失准角条件下,研究了自抗扰捷联罗经对准算法.基于欧拉平台误差角概念建立了适用于自抗扰控制的二阶水平通道状态空间模型.以水平速度误差作为量测实现水平姿态对准,从稳定的水平通道指令角速度中提取方位失准角信息,完成方位自对准.仿真结果表明,该对准算法可较快地实现大失准角的自对准且对准精度与经典罗经对准法相当.%The problems associated with large initial misalignment angles for the so called gyrocompass alignment of strapdown inertial navigation system(SINS) is considered. In this work, the analysis of gyrocompass alignment is approached from active disturbance rejection control (ADRC) theory point of view, which is called ADRC gyrocompass alignment. Based on Euler platform error angles nonlinear error model, the two-order state space model which is applicable to ADRC for level loop alignment is developed. The level loop command rate obtained from the level velocity error is fed into transformation matrix for integration driving the level misalignment angles to zero. When the system is leveled, the level command rate for leveling the transformation matrix is in the steady state which can be used to calculate the azimuth misalignment angle. The numerical simulation results show that the ADRC gyrocompass alignment can quickly achieve alignment independent on initial misalignment angles but with the same accuracy as the classical gyrocompass alignment.

  10. Low Cost Gyrocompass.


    the presence of tilt, oni lman fi- ter design. 7i’RFOR:ANCE U:CDE O𔄁RATIC-AL z ;ViDc""--TS (1) Low frequency (,I Hz.) wind-induced motion (trailer...0015" peak to peak. The new rectilinear flexure suspension and gyro mass will have a natural frequency of about .01 7! z . due to the relatively high...horizor.tal and vertical cross-sections through pairs of flexures to illustrate both the problem geerated by the pendulous suspensior. and the elegant

  11. 基于大失准角时变参数罗经初始对准算法%Variable parameter gyrocompass alignment algorithm based on large error angle model

    翁浚; 严恭敏; 秦永元; 张金红


    To solve the initial self-alignment problem of strapdown inertial navigation system(SINS) under large error angle condition, a new gyrocompass alignment scheme is put forward by analyzing SINS large error angle model and based on the principle of compass effect in platform inertial navigation system(PINS). The scheme can be divided into three steps: horizontal alignment with azimuth angle uncertainty; time-vary parameter gyrocompass alignment for large error angle; fixed parameter gyrocompass alignment. Converge time can be shorten by adjusting gyrocompass parameter in real time in this scheme. A more accurate error transfer mode in strapdown inertial navigation system(SINS) is depicted by large azimuth error angle model instead of small error angle model. At last, a simulation is made using this scheme which shows that the gyro bias is stabilized at 0.01 (°)/h, and azimuth precision can reach 1° in 60 s and 3' at end of alignment.%为了解决大失准角条件下的捷联惯导初始自对准问题,通过分析捷联惯导系统大失准角误差模型,利用平台惯导系统罗经对准原理,提出了一种新的捷联惯导系统罗经对准方案.该方案的具体实现划分为三个阶段:方位角未知情况下的水平对准;大失准角时变参数罗经方位对准;定参数罗经对准.该方案通过实时调节罗经参数缩短了对准时间;利用大方位失准角模型代替小失准角模型,在算法收敛阶段更加准确地描述了捷联惯导系统的误差传递方式.仿真试验表明,使用陀螺随机漂移稳定性为0.01(°)/h的捷联惯导系统,该对准方案能在60 s内方位精度到达1°,并能在对准结束时达到3′的方位对准精度.

  12. 准直误差对磁浮寻北仪寻北精度的影响分析%Influence Analysis of Collimation Error on North-Seeking Precision About Magnetic Levitation Gyrocompass

    谭立龙; 仲启媛; 黄先祥; 王姣; 王亮


    From the north-seeking principle of the magnetic levitation gyrocompass north-seeking instrument, the earth’s rotation angular velocity is decomposed to the gyro coordinate system. The north-seeking error is analyzed under the existing of collimation error and the relational expression between the collimation error and the north-seeking error is derived which be used for north-seeking accuracy compensation calculation. By this way, the problem of the precise collimation consume time resulting in the total north seeking time extended is avoided. The actual application shows that collimating range from 3" expand to 1', can shorten the magnetic levitation closed time about 60 s, by measuring the collimation error and compensating calculation, but the total north-seeking accuracy has not changed.%  从磁悬浮陀螺寻北仪的寻北原理出发,将地球自转角速度分解到陀螺坐标系上,分析了存在准直误差的情况下所引起的寻北误差,推导出了用于补偿运算的准直误差与寻北误差之间的关系表达式,避免了精确准直消耗时间造成总寻北时间延长的问题。实际应用结果表明:准直范围由3″扩大到1′,可缩短磁浮闭路时间约60 s,通过测量准直误差并补偿,仪器总寻北精度没有改变。

  13. 46 CFR 169.807 - Notice of casualty.


    ... 46 Shipping 7 2010-10-01 2010-10-01 false Notice of casualty. 169.807 Section 169.807 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL VESSELS..., navigation charts, navigation work books, compass deviation cards, gyrocompass records, record of draft,...

  14. Rate Gyroscopic Wellbore Survey System

    Sheng Limin


    @@ The rate gyroscopic wellbore survey system as a new type of survey instruments adopts the inertial-grade rate gyro and quartz flexible accelerometers to compose a gyrocompassing system, transiting data to surface instrument by single core cable. The azimuth, inclination and tool-face angle can be computed from these data by surface computer.

  15. A marine direction finding system based on global positioning system

    Dǎnişor, Alin; Izet-Ünsalan, Kunsel-Özel; Ünsalan, Deniz; Tamaş, Razvan; Dǎnişor, Cosmin


    Direction finding and attitude determination is of utmost importance for marine, aerial, spatial and land-based navigation [1], as well as control of vehicles, in surveying and in target acquisition of tracking radars. These problems can be solved using dedicated sensors commonly named as compasses and rate gyros. Unfortunately, the classical means of attitude determination both by magnetic and gyrocompasses become unusable at extreme latitudes. Furthermore, gyrocompasses inherently yield erroneous results on high speed craft. Three-axis attitude of a vehicle can be determined using a GPS receiver with multiple antennas, by measuring carrier phases [2], signal strength [3], or integrated INS/GPS systems [4]. This paper proposes a new method of attitude determination using two low-cost GPS receivers.

  16. Multiple IMU system test plan, volume 4. [subroutines for space shuttle requirements

    Landey, M.; Vincent, K. T., Jr.; Whittredge, R. S.


    Operating procedures for this redundant system are described. A test plan is developed with two objectives. First, performance of the hardware and software delivered is demonstrated. Second, applicability of multiple IMU systems to the space shuttle mission is shown through detailed experiments with FDI algorithms and other multiple IMU software: gyrocompassing, calibration, and navigation. Gimbal flip is examined in light of its possible detrimental effects on FDI and navigation. For Vol. 3, see N74-10296.

  17. The Coriolis field

    Costa, L Filipe


    We present a pedagogical discussion of the Coriolis field, emphasizing its not-so-well-understood aspects. We show that this field satisfies the field equations of the so-called Newton-Cartan theory, a generalization of Newtonian gravity that is covariant under changes of arbitrarily rotating and accelerated frames. Examples of solutions of this theory are given, including the Newtonian analogue of the G\\"odel universe. We discuss how to detect the Coriolis field by its effect on gyroscopes, of which the gyrocompass is an example. Finally, using a similar framework, we discuss the Coriolis field generated by mass currents in general relativity, and its measurement by the Gravity Probe B and LAGEOS/LARES experiments.

  18. The Coriolis field

    Costa, L. Filipe; Natário, José


    We present a pedagogical discussion of the Coriolis field, emphasizing its not-so-well-understood aspects. We show that this field satisfies the field equations of the so-called Newton-Cartan theory, a generalization of Newtonian gravity that is covariant under changes of arbitrarily rotating and accelerated frames. Examples of solutions of this theory are given, including the Newtonian analogue of the Gödel universe. We discuss how to detect the Coriolis field by its effect on gyroscopes, of which the gyrocompass is an example. Finally, using a similar framework, we discuss the Coriolis field generated by mass currents in general relativity, and its measurement by the gravity probe B and LAGEOS/LARES experiments.

  19. Quantum imaging for underwater arctic navigation

    Lanzagorta, Marco


    The precise navigation of underwater vehicles is a difficult task due to the challenges imposed by the variable oceanic environment. It is particularly difficult if the underwater vehicle is trying to navigate under the Arctic ice shelf. Indeed, in this scenario traditional navigation devices such as GPS, compasses and gyrocompasses are unavailable or unreliable. In addition, the shape and thickness of the ice shelf is variable throughout the year. Current Arctic underwater navigation systems include sonar arrays to detect the proximity to the ice. However, these systems are undesirable in a wartime environment, as the sound gives away the position of the underwater vehicle. In this paper we briefly describe the theoretical design of a quantum imaging system that could allow the safe and stealthy navigation of underwater Arctic vehicles.

  20. 硬件在环船舶模拟器的设计与实现%Design and Implementation of Hardware in Loop Ship Simulator

    李向阳; 黄健


    Aiming at the problem of lacking ship simulation object and marine standard signal in development process of ship electronic equipment, the hardware in loop ( HIL) ship simulator is designed. The ARM SCM LM3S1958 is selected as the main control chip, the design ideas for rudder angle measurement circuit, communication interface circuit and output circuit of gyrocompass are introduced in detail, and the data flow of the system t block diagram of the main program as well as the main software algorithms are given. This simulator can emulate operational state of different types of ships, as well as output standard signals of gyrocompass, rudder angle and GPS, and also create step and sine disturbing signals. The simulator has been successfully applied in the development process of ship electronic equipment, e. g. , steering controller and repeater, etc.%针对在船舶电子设备开发过程中缺乏船舶模拟对象和船用标准信号的问题,设计了硬件在环船舶模拟器.选用ARM单片机LM3S1958作为模拟器的主控芯片,洋细设计了舵角测量电路、通信接口电路和步进电罗经输出电路,分别给出了系统数据流图、主程序框图和主要软件算法.该模拟器可以模拟不同类型的船舶运行状况,输出电罗经、舵角和GPS标准信号,产生阶跃和正弦等扰动信号.该模拟器已成功应用于航向控制器和复示器等船舶电子设备的开发过程中.

  1. Fiber optic gyro development at Fibernetics

    Bergh, Ralph A.; Arnesen, Leif; Herdman, Craig


    Fiber optic gyroscope based inertial sensors are being used within increasingly severe environments, enabling unmanned systems to sense and navigate in areas where GPS satellite navigation is unavailable or jammed. A need exists for smaller, lighter, lower power inertial sensors for the most demanding land, sea, air, and space applications. Fibernetics is developing a family of inertial sensor systems based on our closed-loop navigation-grade fiber optic gyroscope (FOG). We are making use of the packaging flexibility of the fiber to create a navigation grade inertial measurement unit (IMU) (3 gyroscopes and 3 accelerometers) that has a volume of 102 cubic inches. We are also planning a gyrocompass and an inertial navigation system (INS) having roughly the same size. In this paper we provide an update on our development progress and describe our modulation scheme for the Sagnac interferometers. We also present a novel multiplexed design that efficiently delivers source light to each of the three detectors. In our future development section we discuss our work to improve FOG performance per unit volume, specifically detailing our focus in utilizing a multicore optical fiber.

  2. The practical Einstein experiments, patents, inventions

    Illy, József


    Albert Einstein may be best known as the wire-haired whacky physicist who gave us the theory of relativity, but that's just one facet of this genius' contribution to human knowledge and modern science. As Jozsef Illy expertly shows in this book, Einstein had an eminently practical side as well. As a youth, Einstein was an inveterate tinkerer in the electrical supply factory his father and uncle owned and operated. His first paid job was as a patent examiner. Later in life, Einstein contributed to many inventions, including refrigerators, microphones, and instruments for aviation. In published papers, Einstein often provided ways to test his theories and fundamental problems of the scientific community of his times. He delved deeply into a variety of technological innovations, most notably the gyrocompass, and consulted for industry in patent cases and on other legal matters. Einstein also provided explanations for common and mundane phenomena, such as the meandering of rivers. In these and other hands-on exam...

  3. Compact, highly sensitive optical gyros and sensors with fast-light

    Christensen, Caleb A.; Zavriyev, Anton; Cummings, Malcolm; Beal, A. C.; Lucas, Mark; Lagasse, Michael


    Fast-light phenomena can enhance the sensitivity of an optical gyroscope of a given size by several orders of magnitude, and could be applied to other optical sensors as well. MagiQ Technologies has been developing a compact fiber-based fast light Inertial Measurement Unit (IMU) using Stimulated Brillouin Scattering in optical fibers with commercially mature technologies. We will report on our findings, including repeatable fast-light effects in the lab, numerical analysis of noise and stability given realistic optical specs, and methods for optimizing efficiency, size, and reliability with current technologies. The technology could benefit inertial navigation units, gyrocompasses, and stabilization techniques, and could allow high grade IMUs in spacecraft, unmanned aerial vehicles or sensors, where the current size and weight of precision gyros are prohibitive. By using photonic integrated circuits and telecom-grade components along with specialty fibers, we also believe that our design is appropriate for development without further advances in the state of the art of components.

  4. A practical approach to fast-light enhanced fiber sensing: experiments and modeling

    Christensen, Caleb A.; Zavriyev, Anton; Cummings, Malcolm; Beal, A. Craig; Lucas, Mark; Lagasse, Michael


    It has been proposed that fast-light optical phenomena can increase the sensitivity of an optical gyroscope of a given size by several orders of magnitude. MagiQ Technologies is developing a compact fiber-based fast light Inertial Measurement Unit (IMU) using Stimulated Brillouin Scattering (SBS) in optical fibers with commercially mature technologies. We have demonstrated repeatable fast-light effects in the lab using off-the shelf optical components. Numerical analysis has revealed the requirements for stable, sensitive operation of gyroscopes, accelerometers or other sensors, as well as identified methods for optimizing efficiency, size, and reliability with known optical technologies. By using photonic integrated circuits and telecom-grade components along with specialty fibers, our design would be appropriate for mass production. We have eliminated all free-space optical elements or wavelength dependent elements such as atomic vapor cells in order to enable a compact, high sensitivity IMU stable against environmental disturbances. Results of this effort will have benefits in existing applications of IMUs (such as inertial navigation units, gyrocompasses, and stabilization techniques), and will allow wider use of RLGs in spacecraft, unmanned aerial vehicles or sensors, where the current size and weight of optical IMUs are prohibitive.


    A. Witayangkurn


    Full Text Available The Unmanned Aerial Vehicle (UAV is an emerging technology being adapted for a wide range of applications. Real-time monitoring is essential to enhance the effectiveness of UAV applications. Sensor networks are networks constructed from various sensor nodes. International standard such as OGC's SOS (Sensor Observation Service makes it possible to share sensor data with other systems as well as to provide accessibility to globally distributed users. In this paper, we propose a system combining UAV technology and sensor network technology to use an UAV as a mobile node of sensor network so that the sensor data from UAV is published and shared real-time. A UAV can extend the observation range of a sensor network to remote areas where it is usually difficult to access such as disaster area. We constructed a UAV system using remote-controlled helicopter and various sensors such as GPS, gyrocompass, laser range finder, Digital camera and Thermometer. Furthermore, we extended the Sensor Observation Service (SOS and Sensor Service Grid (SSG to support mobile sensor nodes. Then, we conducted experiments of flying the helicopter over an area of the interest. During the flight, the system measured environmental data using its sensors and captured images of the ground. The data was sent to a SOS node as the ground station via Wi-Fi which was published using SSG to give real- time access to globally distributed users.

  6. Local positioning system

    Kyker, R.


    Navigation systems have been vital to transportation ever since man took to the air and sea. Early navigation systems utilized the sextant to navigate by starlight as well as the magnetic needle compass. As electronics and communication technologies improved, inertial navigation systems were developed for use in ships and missile delivery. These systems consisted of electronic compasses, gyro-compasses, accelerometers, and various other sensors. Recently, systems such as LORAN and the Global Positioning System (GPS) have utilized the properties of radio wave propagation to triangulate position. The Local Positioning System (LPS), described in this paper, is an implementation of a limited inertial navigation system designed to be used on a bicycle. LPS displays a cyclist`s current position relative to a starting location. This information is displayed in Cartesian-like coordinates. To accomplish this, LPS relies upon two sensors, an electronic compass sensor and a distance sensor. The compass sensor provides directional information while the distance sensor provides the distance traveled. This information yields a distance vector for each point in time which when summed produces the cyclist`s current position. LPS is microprocessor controlled and is designed for a range of less than 90 miles.

  7. Advanced Navigation System for Aircraft Applications

    G. Satheesh Reddy


    Full Text Available Various forms of navigation are present in today’s world, leading from satellite based navigation to several archaic forms of navigation like star gazing. Now, lots of technologies are available to achieve this but with certain limitations. For example, FOG based navigation provides accuracy with in 0.10-100 range which is not sufficient for various military applications. Therefore, there is a need to design a system which will have better accuracy and thus requires development of ring laser gyro-based inertial systems. This paper concentrates on the aided navigation system based on ring laser gyro of 0.01 deg/hr class and GPS - GLONASS to further enhance the capability of system in terms of accuracy. The usage of such systems not only provides accurate results momentarily but it also persists for longer duration with the aid of GPS - GLONASS for applications like aircraft, ship and long range missiles. The system provides accuracy of the level of 1 Nm/hr in pure navigation and 30 m with the aid of GPS - GLONASS. Apart from this, the availability of gyro-compass and baro-inertial algorithms further enhances the system capabilities and made them self dependent to the major extent.Defence Science Journal, 2013, 63(2, pp.131-137, DOI:

  8. 基于正逆向与降噪的捷联惯导改进快速对准方法%Improved fast alignment method of strapdown INS using bidirectional processes and denoising

    覃方君; 李安; 许江宁


    针对捷联惯性导航系统(INS)的快速对准问题,基于双向过程和惯性传感器的降噪方法,提出了一种改进的对准方法。利用双向过程(前向和逆向)反复处理保存的惯性测量单元(IMU)的数据序列实现快速对准,推导了一种新的前向与逆向对准关系。为了减少角随机游走误差的影响,基于小波变换的降噪方法抑制光纤陀螺(FOGs)和加速度计噪声,给出陀螺罗经回路的改进方法的整个流程,并在自研的光纤陀螺捷联惯导系统上进行测试。实测数据实验结果表明,经正逆向与降噪改进后的快速对准方法具有更快的收敛速度,能在不到3 min内完成对准任务,同时也具有更好的对准精度。%To solve fast alignment problem for strapdown inertial navigation system(INS), an improved alignment method is proposed using bidirectional processes and inertial sensors denoising. It is proved that repeatedly making use of the bidirectional processes(forward and backward ) to process the saved inertial measurement unit(IMU) data sequence could help fast alignment. A new relationship between forward and backward processes for alignment is deviated. In order to reduce the effect of angular random walk error, a wavelet-based demoising method is adopted to suppress the noises of fiber optical gyroscopes(FOGs) and accelerometers. And the whole procedure of the improved method based on gyrocompassing loop is given. The fast alignment method has been tested on a self-made FOG strapdown INS. The experiment results show that the improved method has great advantage in alignment speed, which costs less than 3 min to complete the alignment mission, and also has higher alignment accuracy after offline denoising the inertial sensors.

  9. 舰载机大失准角的快速二次传递对准方法%Rapid second time transfer alignment of large misalignment for carrier aircrafts

    孙枫; 吴旭; 王根


    针对舰载机传递对准特点,直接利用主惯导的导航信息进行一次装订,引入了大失准角对准问题.为了解决舰载机传递对准问题,提出利用子惯导自主对准进行一次装订减小子惯导中间坐标系与主惯导间的失准角.分析Wahba问题提出统计意义的Quaternion(四元数)对准方法替换传统的Triad(双矢定姿)对准方法,提高了多信息冗余度和对准精度.基于分级修正思想,提出二次传递对准方法,第一次传递基于非线性模型和自适应渐消扩展卡尔曼滤波,并给出简化的渐消因子计算方法;第二次传递对准基于线性误差模型,采用速度+航向匹配,在补偿失准角的基础上,估计陀螺漂移.仿真结果表明二次传递方法能够满足舰载机传递对准需求.%Using the master inertial navigation system(MINS) navigation information,the slave inertial navigation system(SINS) was introduce to solve the large misalignment problem of the carrier aircraft transfer.The self-alignment was adopted before the transfer alignment to reduce the misalignment between the MINS and SINS.Then the Triad alignment method was replaced by statistical Quaternion method based on the solution of Wahba problem,which improved the alignment accuracy and redundancy.Then based on the cascaded calibration method,a second time transfer alignment was presented.The first alignment was based on the nonlinear error model and adaptive fading extended Kalman filter(AFEKF),and a new method of calculating fading factor was presented.The second alignment based on the linear error model,adopting velocity-yaw matching method not only estimate and compensate the misalignment angles,but also estimated the gyrocompass drift.The simulation results show that this method can satisfy the requirement for the carrier aircraft transfer alignment.

  10. Preliminary Polar Sea Trials of Nereid-UI: A Remotely Operated Underwater Vehicle for Oceanographic Access Under Ice

    Whitcomb, L. L.; Jakuba, M.; German, C. R.; Bowen, A.; Yoerger, D.; Kinsey, J. C.; Mayer, L.; McFarland, C.; Suman, S.; Bailey, J.; Judge, C.; Elliott, S.; Gomez-Ibanez, D.; Taylor, C. L.; Machado, C.; Howland, J. C.; Kaiser, C.; Heintz, M.; Pontbriand, C.; O'Hara, L.; McDonald, G.; Boetius, A.


    We report the development and deployment of a remotely-controlled underwater robotic vehicle capable of being teleoperated under ice under real-time human supervision. The Nereid Under-Ice (Nereid-UI or NUI) vehicle enables exploration and detailed examination of biological and physical environments including the ice-ocean interface in marginal ice zones, in the water column of ice-covered seas, at glacial ice-tongues, and ice-shelf margins, delivering realtime high definition video in addition to survey data from on board acoustic, optical, chemical, and biological sensors. The vehicle employs a novel lightweight fiber-optic tether that will enable it to be deployed from a ship to attain standoff distances of up to 20 km from an ice-edge boundary. We conducted NUI's first under-ice deployments during the July 2014 F/V Polarstern PS86 expedition at 86° N 6 W° in the Arctic Ocean - near the Aurora hydrothermal vent site on the Gakkel Ridge approximately 200 km NE of Greenland. We conducted 4 dives to evaluate and develop NUI's overall functioning and its individual engineered subsystems. On each dive, dead-reckoning (Ice-locked Doppler sonar and north-seeking gyrocompass) complemented by acoustic ranging provided navigation, supporting closed-loop control of heading, depth, and XY position relative to the ice. Science operations included multibeam transects of under-ice topography, precision vertical profiles for the bio-sensor suite and IR/radiance sensor suite, IR/radiance/multibeam transects at constant depth interlaced with vertical profiles and upward-looking digital still-camera surveys of the ice, including areas rich with algal material. The fiber-optic tether remained intact throughout most of all 4 dives. Consistent with the NUI concept of operations, in 3 of 4 dives the fiber-optic tether eventually failed, and the vehicle was then commanded acoustically in a series of short-duration maneuvers to return to Polarstern for recovery. These preliminary

  11. First Gravity Traverse on the Martian Surface from the Curiosity Rover

    Lewis, K. W.; Peters, S. F.; Gonter, K. A.; Vasavada, A. R.


    Orbital gravity surveys have been a key tool in understanding planetary interiors and shallow crustal structure, exemplified by recent missions such as GRAIL and Juno. However, due to the loss of spatial resolution with altitude, airborne and ground-based survey methods are typically employed on the Earth. Previously, the Lunar Traverse Gravimeter experiment on the Apollo 17 mission has been the only attempt to collect surface gravity measurements on another planetary body. We will describe the results of the first gravity survey on the Martian surface, using data from the Curiosity rover over its >10 km traverse across the floor of Gale crater and lower slopes of Mount Sharp. These results enable us to estimate bulk rock density, and to search for potential subsurface density anomalies. To measure local gravitational acceleration, we use one of the two onboard Rover Inertial Measurement Units (RIMU-A), designed for rover position and fine attitude determination. The IMU contains three-axis micro-electromechanical (MEMS) accelerometers and fiber-optic gyros, and is used for gyrocompassing by integrating data for several minutes on sols with no drive or arm motions (roughly 50% of sols to date). Raw acceleration data are calibrated for biases induced by temperature effects and rover orientation, along with rover elevation over the course of the mission using multiple regression. We use the best fit linear relationship between topographic height and gravitational acceleration to estimate a Bouguer correction for the observed change in magnitude over the mission as the rover has ascended over 100 meters up the lower slopes of Mount Sharp. We find a relatively low best-fit density of 1600 +/- 500 kg/m^3 for the rocks of Mount Sharp, consistent with rover-based measurements of thermal inertial, and potentially indicating pervasive fracturing, high porosity and/or low compaction within the original sediments at least to depths of order 100 meters. Future measurements

  12. Constraining calving front processes on W Greenland outlet glaciers using inertial-corrected laser scanning & swath-bathymetry

    Bates, R.; Hubbard, A.; Neale, M.; Woodward, J.; Box, J. E.; Nick, F.


    Calving and submarine melt account for the majority of loss from the Antarctic and over 50% of that from the Greenland Ice Sheet. These ice-ocean processes are highly efficient mass-loss mechanisms, providing a rapid link between terrestrial ice (storage) and the oceanic sink (sea level/freshwater flux) which renders the ocean-outlet-ice sheet system potentially highly non-linear. Despite this, the controls on tidewater processes are poorly understood and a process based description of them is lacking from the present generation of coupled ice sheet models. We present details from an innovative study where two survey techniques are integrated to enable the construction of accurate, ~m resolution 3d digital terrain models (DTMs) of the aerial and submarine ice front of calving outlet glaciers. A 2km range terrestrial laser scanner was combined with a 416KHz swath-interferometric system and corrected via an inertial motion unit stabilized by RTK GPS and gyro-compass data. The system was mounted aboard a heavy displacement (20,000kg) yacht in addition to a light displacement (100kg) semi-autonomous boat and used to image the aerial and submarine calving fronts of two large outlet glaciers in W Greenland. Six daily surveys, each 2.5km long were repeated across Lille Glacier during which significant ice flow, melt and calving events were observed and captured from on-ice GPS stations and time-lapse sequences. A curtain of CTD and velocity casts were also conducted to constrain the fresh and oceanic mass and energy fluxes within the fjord. The residual of successive DTMs yield the spatial pattern of frontal change enabling the processes of aerial and submarine calving and melt to be quantified and constrained in unprecedented detail. These observed frontal changes are tentatively related to local dynamic, atmospheric and oceanographic processes that drive them. A partial survey of Store Glacier (~7km calving front & W Greenland 2nd largest outlet after Jakobshavn Isbrae

  13. Shipboard Satellite TV and Remote Sensing Receiving System%船载卫星电视/遥感接收系统

    刘晓明; 艾文光


    A shipboard satellite TV and remote sensing receiving system (SSTV/RSRS) is developed to acquire global remote sensing data for scientific study and weather forecast to increase the ocean voyage safety, and to enrich the entertainment of ship’s crew. The system adopts stability scheme of two-axis stability platform and two-axis servo. The two-axis stability platform overcomes the impacts of ship swing. Two-axis antenna system implements the accurate tracking of the antenna to polar orbit satellites or geostationary satellites, and the receiving of remote sensing data or satellite TV programs. Using dual GPS attitude measurement system and auxiliary precision gyrocompass provided the course information. The ship orientation is compensated by antenna control unit. The influence of ship orientation change on orbit tracking is solved. Use tracking scheme of orbit prediction-based step-track. The system has been used for 3 years on a ship. The results show that the system can receive and process the remote sensing data of polar orbit satellites such as US NOAA, ORBVIEW and Chinese FENGYUN, etc. When a polar orbit pass is over, it receives TV signals from geostationary satellite automatically.%  为了获取全球卫星遥感数据进行科学研究,并利用遥感数据进行气象预报,提高远洋船的航行安全;同时,为了丰富船员的业余文化生活,研制了船载卫星电视/遥感接收系统(shipboard satellite TV and remote sensing receiving system,SSTV-RSRS)。系统采用二轴稳定平台加二轴伺服的稳定方案。二轴稳定平台克服船的摇摆对跟踪的影响;二轴天线系统精确跟踪极轨卫星和同步卫星,完成船载条件下的遥感数据接收和卫星电视接收。双GPS姿态测量系统及辅助的精密电罗经提供航向信息,由天线控制单元提供补偿,解决舰船的航向变化对轨道跟踪的影响。采用轨道预报程序跟踪加步进跟踪方案

  14. Fast alignment algorithm of inertial fixed frame in quasi-static environment%伪静态环境凝固惯性系快速对准算法

    刘学俊; 李永涛


    惯性导航系统在开始工作时需要进行初始对准从而确定初始姿态。提出了一种与经典的对准算法如陀螺罗经或卡尔曼滤波技术不同的凝固惯性系快速(IF3)对准算法。可在任意初始误差条件下进行对准,且能适应高频扰动环境。将姿态矩阵分解成地球自转、惯性速率和对准矩阵三个部分。对准矩阵依靠两组分别处于不同惯性系里的观测向量确定。通过采用前置平滑滤波、层叠采样和二重积分技术,对准精度显著改善。在载车发动机怠速运行和人员上下车扰动条件下,60 s对准误差优于1 mil (1),180 s对准误差优于0.6 mil(1),300 s对准误差优于0.4 mil(1)。实验结果证明了IF3对准算法的快速性、准确性和鲁棒性。%An initial alignment is needed to determine the initial attitude when inertial navigation system(INS) start to work. In this paper, an inertial fixed frame fast(IF3) alignment algorithm is devised, in contrast to the classic alignment algorithms, such as gyrocompassing and Kalman filtering techniques. Unlike classic techniques, the IF3 alignment is effective with any initial attitude error, as well as high frequency vibrations. The estimator is based on decomposing the attitude matrix into separate earth motion, inertial rate, and alignment matrix. And the alignment matrix is determined by two sets of observation vectors in different inertial fixed frames. By smooth pre-filtering, interleaved sampling and double integrating the observation vectors, it is shown that the precision of attitude estimates is improved. The IF3 alignment heading error is less than 1 mil(1) within 60 s, 0.6 mil(1) within 180 s, and 0.4 mil(1) within 300 s under the condition that the vehicle engine is running at idle and intended introducing the perturbation caused by a person’s getting on and off the vehicle. Experiment tests favorably demonstrate its rapidness, accuracy and