WorldWideScience

Sample records for satellite multibeam phased

  1. Robust Precoding Design for Multibeam Downlink Satellite Channel with Phase Uncertainty

    OpenAIRE

    Gharanjik, Ahmad; Shankar, Bhavani; Arapoglou, Pantelis-Daniel; Bengtsson, Mats

    2015-01-01

    In this work, we study the design of a precoder on the user downlink of a multibeam satellite channel. The variations in channel due to phase noise introduced by on-board oscillators and the long round trip delay result in outdated channel information at the transmitter. The phase uncertainty is modelled and a robust design framework is formulated based on availability and power constraints. The optimization problem is cast into the convex paradigm after approximations and the benefits of the...

  2. Advanced Communication Technology Satellite (ACTS) multibeam antenna technology verification experiments

    Science.gov (United States)

    Acosta, Roberto J.; Larko, Jeffrey M.; Lagin, Alan R.

    1992-01-01

    The Advanced Communication Technology Satellite (ACTS) is a key to reaching NASA's goal of developing high-risk, advanced communications technology using multiple frequency bands to support the nation's future communication needs. Using the multiple, dynamic hopping spot beams, and advanced on board switching and processing systems, ACTS will open a new era in communications satellite technology. One of the key technologies to be validated as part of the ACTS program is the multibeam antenna with rapidly reconfigurable hopping and fixed spot beam to serve users equipped with small-aperature terminals within the coverage areas. The proposed antenna technology experiments are designed to evaluate in-orbit ACTS multibeam antenna performance (radiation pattern, gain, cross pol levels, etc.).

  3. On intermodulation beams of satellite DBF transmitting multibeam array antenna

    Science.gov (United States)

    Zhao, Hongmei; Wang, Huali; Mu, Shanxiang

    2007-11-01

    Digital beamforming (DBF) transmitting multibeam planar array antenna with nonlinear behaviors of solid-state power amplifiers (SSPA) is discussed. This paper investigates the intermodulation beams produced by the nonlinearity characteristics of the SSPA with multiple carrier components. The Shimbo model is simplified to describe the nonlinear behaviors of SSPA. The optimal SSPA input back-off (IBO) point which is given the desired the carrier and the intermodulatin ratio (C/IM) is simulated. And the tradeoffs between linearity and efficiency of the power amplifier which influence this IBO is also discussed, helping to selecting suitable SSPA device and reducing the dc power consumption in satellite array antenna system.

  4. Mosaic of gridded multibeam bathymetry and bathymetry derived from multispectral IKONOS satellite imagery of Tutuila Island, American Samoa, USA

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Gridded multibeam bathymetry is integrated with bathymetry derived from multispectral IKONOS satellite data. Gridded (5 m cell size) multibeam bathymetry collected...

  5. Mosaic of gridded multibeam bathymetry and bathymetry derived from multispectral IKONOS satellite imagery of Rose Atoll, American Samoa, USA

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Gridded multibeam bathymetry is integrated with bathymetry derived from multispectral IKONOS satellite data. Gridded (5 m cell size) multibeam bathymetry were...

  6. Frequency Estimation in Iterative Interference Cancellation Applied to Multibeam Satellite Systems

    Directory of Open Access Journals (Sweden)

    Ducasse A

    2007-01-01

    Full Text Available This paper deals with interference cancellation techniques to mitigate cochannel interference on the reverse link of multibeam satellite communication systems. The considered system takes as a starting point the DVB-RCS standard with the use of convolutional coding. The considered algorithm consists of an iterative parallel interference cancellation scheme which includes estimation of beamforming coefficients. This algorithm is first derived in the case of a symbol asynchronous channel with time-invariant carrier phases. The aim of this article is then to study possible extensions of this algorithm to the case of frequency offsets affecting user terminals. The two main approaches evaluated and discussed here are based on (1 the use of block processing for estimation of beamforming coefficients in order to follow carrier phase variations and (2 the use of single-user frequency offset estimations.

  7. Performance Analysis of Integrated Wireless Sensor and Multibeam Satellite Networks Under Terrestrial Interference

    Directory of Open Access Journals (Sweden)

    Hongjun Li

    2016-10-01

    Full Text Available This paper investigates the performance of integrated wireless sensor and multibeam satellite networks (IWSMSNs under terrestrial interference. The IWSMSNs constitute sensor nodes (SNs, satellite sinks (SSs, multibeam satellite and remote monitoring hosts (RMHs. The multibeam satellite covers multiple beams and multiple SSs in each beam. The SSs can be directly used as SNs to transmit sensing data to RMHs via the satellite, and they can also be used to collect the sensing data from other SNs to transmit to the RMHs. We propose the hybrid one-dimensional (1D and 2D beam models including the equivalent intra-beam interference factor β from terrestrial communication networks (TCNs and the equivalent inter-beam interference factor α from adjacent beams. The terrestrial interference is possibly due to the signals from the TCNs or the signals of sinks being transmitted to other satellite networks. The closed-form approximations of capacity per beam are derived for the return link of IWSMSNs under terrestrial interference by using the Haar approximations where the IWSMSNs experience the Rician fading channel. The optimal joint decoding capacity can be considered as the upper bound where all of the SSs’ signals can be jointly decoded by a super-receiver on board the multibeam satellite or a gateway station that knows all of the code books. While the linear minimum mean square error (MMSE capacity is where all of the signals of SSs are decoded singularly by a multibeam satellite or a gateway station. The simulations show that the optimal capacities are obviously higher than the MMSE capacities under the same conditions, while the capacities are lowered by Rician fading and converge as the Rician factor increases. α and β jointly affect the performance of hybrid 1D and 2D beam models, and the number of SSs also contributes different effects on the optimal capacity and MMSE capacity of the IWSMSNs.

  8. Performance Analysis of Integrated Wireless Sensor and Multibeam Satellite Networks Under Terrestrial Interference.

    Science.gov (United States)

    Li, Hongjun; Yin, Hao; Gong, Xiangwu; Dong, Feihong; Ren, Baoquan; He, Yuanzhi; Wang, Jingchao

    2016-10-14

    This paper investigates the performance of integrated wireless sensor and multibeam satellite networks (IWSMSNs) under terrestrial interference. The IWSMSNs constitute sensor nodes (SNs), satellite sinks (SSs), multibeam satellite and remote monitoring hosts (RMHs). The multibeam satellite covers multiple beams and multiple SSs in each beam. The SSs can be directly used as SNs to transmit sensing data to RMHs via the satellite, and they can also be used to collect the sensing data from other SNs to transmit to the RMHs. We propose the hybrid one-dimensional (1D) and 2D beam models including the equivalent intra-beam interference factor β from terrestrial communication networks (TCNs) and the equivalent inter-beam interference factor α from adjacent beams. The terrestrial interference is possibly due to the signals from the TCNs or the signals of sinks being transmitted to other satellite networks. The closed-form approximations of capacity per beam are derived for the return link of IWSMSNs under terrestrial interference by using the Haar approximations where the IWSMSNs experience the Rician fading channel. The optimal joint decoding capacity can be considered as the upper bound where all of the SSs' signals can be jointly decoded by a super-receiver on board the multibeam satellite or a gateway station that knows all of the code books. While the linear minimum mean square error (MMSE) capacity is where all of the signals of SSs are decoded singularly by a multibeam satellite or a gateway station. The simulations show that the optimal capacities are obviously higher than the MMSE capacities under the same conditions, while the capacities are lowered by Rician fading and converge as the Rician factor increases. α and β jointly affect the performance of hybrid 1D and 2D beam models, and the number of SSs also contributes different effects on the optimal capacity and MMSE capacity of the IWSMSNs.

  9. Adaptive multibeam antennas for spacelab. Phase A: Feasibility study

    Science.gov (United States)

    Allen, C. C.; Applebaum, S. P.; Popowsky, W. J.; Wouch, G.

    1976-01-01

    The feasibility was studied of using adaptive multibeam multi-frequency antennas on the spacelab, and to define the experiment configuration and program plan needed for a demonstration to prove the concept. Three applications missions were selected, and requirements were defined for an L band communications experiment, an L band radiometer experiment, and a Ku band communications experiment. Reflector, passive lens, and phased array antenna systems were considered, and the Adaptive Multibeam Phased Array (AMPA) was chosen. Array configuration and beamforming network tradeoffs resulted in a single 3m x 3m L band array with 576 elements for high radiometer beam efficiency. Separate 0.4m x 0.4 m arrays are used to transmit and receive at Ku band with either 576 elements or thinned apertures. Each array has two independently steerable 5 deg beams, which are adaptively controlled.

  10. Mosaic of gridded multibeam bathymetry and bathymetry derived from multispectral IKONOS satellite imagery of Tau Island, Territory of American Samoa, USA

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Gridded multibeam bathymetry is integrated with bathymetry derived from multispectral IKONOS satellite data. Gridded (10 m cell size) multibeam bathymetry collected...

  11. Mosaic of gridded multibeam bathymetry and bathymetry derived from multispectral IKONOS satellite imagery of Kingman Reef, Pacific Remote Island Area, USA

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Gridded multibeam bathymetry is integrated with bathymetry derived from multispectral IKONOS satellite data. Gridded (5 m cell size) multibeam bathymetry collected...

  12. Mosaic of gridded multibeam bathymetry and bathymetry derived from multispectral IKONOS satellite imagery of Johnston Atoll, Pacific Remote Island Area, USA

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Gridded multibeam bathymetry is integrated with bathymetry derived from multispectral IKONOS satellite data. Gridded (5 m cell size) multibeam bathymetry collected...

  13. Mosaic of 10 m gridded multibeam bathymetry and bathymetry derived from multispectral IKONOS satellite imagery of Maug Island, Commonwealth of the Northern Marianas Islands, USA

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Gridded multibeam bathymetry is integrated with bathymetry derived from multpectral IKONOS satellite data. Gridded (5m and 10 m cell size) multibeam bathymetry...

  14. Mosaic of 5 m gridded multibeam bathymetry and bathymetry derived from multispectral IKONOS satellite imagery of Maug Island, Commonwealth of the Northern Marianas Islands, USA

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Gridded multibeam bathymetry is integrated with bathymetry derived from multpectral IKONOS satellite data. Gridded (5m and 10 m cell size) multibeam bathymetry...

  15. Mosaic of gridded multibeam bathymetry and bathymetry derived from multispectral IKONOS satellite imagery of Ofu and Olosega Islands, Territory of American Samoa, USA

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Gridded multibeam bathymetry is integrated with bathymetry derived from multipectral IKONOS satellite data. Gridded (5 m cell size) multibeam bathymetry collected...

  16. Mosaic of 10 m gridded multibeam bathymetry and bathymetry derived from multispectral IKONOS satellite imagery of Asuncion Island, Commonwealth of the Northern Marianas Islands, USA

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Gridded multibeam bathymetry is integrated with bathymetry derived from multpectral IKONOS satellite data. Gridded (10 m cell size) multibeam bathymetry collected...

  17. Mosaic of 5 m gridded multibeam bathymetry and bathymetry derived from multispectral IKONOS satellite imagery of Asuncion Island, Commonwealth of the Northern Marianas Islands, USA

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Gridded multibeam bathymetry is integrated with bathymetry derived from multpectral IKONOS satellite data. Gridded (5 m cell size) multibeam bathymetry collected...

  18. Mosaic of 10 m gridded multibeam bathymetry and bathymetry derived from multispectral IKONOS satellite imagery of Alamagan Island, Commonwealth of Northern Mariana Islands, USA

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Gridded multibeam bathymetry is integrated with bathymetry derived from multispectral IKONOS satellite data. Gridded (10 m cell size) multibeam bathymetry collected...

  19. Mosaic of 5 m gridded multibeam bathymetry and bathymetry derived from multispectral IKONOS satellite imagery of Alamagan Island, Commonwealth of Northern Mariana Islands, USA

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Gridded multibeam bathymetry is integrated with bathymetry derived from multispectral IKONOS satellite data. Gridded (5 m cell size) multibeam bathymetry collected...

  20. Mosaic of gridded multibeam bathymetry and bathymetry derived from multispectral World View-2 satellite imagery of Baker Island, Pacific Remote Island Areas, Central Pacific.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Gridded multibeam bathymetry is integrated with bathymetry derived from multpectral World View-2 satellite data. Gridded (10 m cell size) multibeam bathymetry...

  1. Mosaic of gridded multibeam bathymetry and bathymetry derived from multispectral World View-2 satellite imagery of Sarigan Island, Territory of Mariana, USA.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Gridded multibeam bathymetry is integrated with bathymetry derived from multpectral World View-2 satellite data. Gridded (10 m cell size) multibeam bathymetry...

  2. Mosaic of 5m gridded multibeam bathymetry and bathymetry derived from multispectral World View-2 satellite imagery of Swains Island, Territory of American Samoa, South Pacific, USA

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Gridded multibeam bathymetry is integrated with bathymetry derived from multpectral World View-2 satellite data. Gridded (5 m cell size) multibeam bathymetry...

  3. Mosaic of gridded multibeam bathymetry and bathymetry derived from multispectral World View-2 satellite imagery of Ni'ihau Island, Territory of Main Hawaiian Islands, USA

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Gridded multibeam bathymetry is integrated with bathymetry derived from multpectral World View-2 satellite data. Gridded (5 m cell size) multibeam bathymetry...

  4. Mosaic of gridded multibeam bathymetry and bathymetry derived from multispectral World View-2 satellite imagery of Rota Island, Territory of Mariana, USA

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Gridded multibeam bathymetry is integrated with bathymetry derived from multpectral World View-2 satellite data. Gridded (5 m cell size) multibeam bathymetry...

  5. Mosaic of gridded multibeam bathymetry and bathymetry derived from multispectral IKONOS satellite imagery of Palmyra Atoll, Pacific Remote Island Area, USA

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Gridded multibeam bathymetry is integrated with bathymetry derived from multispectral IKONOS satellite data. Gridded (5 m cell size) multibeam bathymetry collected...

  6. A Multibeam Dual-Band Orthogonal Linearly Polarized Antenna Array for Satellite Communication on the Move

    Directory of Open Access Journals (Sweden)

    Yi Liu

    2015-01-01

    Full Text Available The design and simulation of a 10 × 8 multibeam dual-band orthogonal linearly polarized antenna array operating at Ku-band are presented for transmit-receive applications. By using patches with different coupling methods as elements, both perpendicular polarization in 12.25–12.75 GHz band and horizontal polarization in 14.0–14.5 GHz band are realized in a shared antenna aperture. A microstrip Rotman lens is employed as the beamforming network with 7 input ports, which can generate a corresponding number of beams to cover −30°–30° with 5 dB beamwidth along one dimension. This type of multibeam orthogonal linearly polarized planar antenna is a good candidate for satellite communication (SatCom.

  7. Sunflower array antenna for multi-beam satellite applications

    NARCIS (Netherlands)

    Vigano, M.C.

    2011-01-01

    Saving space on board, reducing costs and improving the antenna performances are tasks of outmost importance in the field of satellite communication. In this work it is shown how a non-uniformly spaced, direct radiating array designed according to the so called ‘sunflower’ law is able to satisfy str

  8. Narrow multibeam satellite ground station antenna employing a linear array with a geosynchronous arc coverage of 60 deg. I - Theory

    Science.gov (United States)

    Amitay, N.; Gans, M. J.

    1982-11-01

    The feasibility of using an appropriately squinted linear scan in narrow multibeam satellite ground station antennas employing phased arrays is demonstrated. This linear scan has the potential of reducing the complexity of a narrow-beam planar array to that of a linear array. Calculations for such antennas placed at cities throughout the U.S. show that the peak beam pointing error in covering the 70 deg W to 130 deg W geosynchronous equatorial arc (GEA) is under 5/1000th of a degree. Communication at a 300 MBd rate in the 12/14 GHz band can be made feasible, for a grating lobe-free scan and 0.5 deg beamwidth antenna, by using a relatively simple time equalization.

  9. NASA ACTS Multibeam Antenna (MBA) System. [Advanced Communications Technology Satellite

    Science.gov (United States)

    Choung, Youn H.; Stiles, W. Herschel; Wu, Joseph; Wong, William C.; Chen, C. Harry

    1986-01-01

    The design of the Advanced Communications Technology Satellite MBA system, which provides both spot beam and scanning beam coverage to both high and low burst rates data-users is examined. The MBA consists of receive and transmit antennas installed on a common precision mounting platform that is integrated to the bus through three flexures; a lightweight system with low thermal distortion is obtained by using composite materials for the MBA structures. The RF design, which is a Cassegrain reflector with a large equivalent focal length/aperture size, is described. Consideration is given to the position of the feed in order to minimize scan loss and sidelobe levels, the size of the subreflector in order to minimize feed spillover, and antenna performance degradation caused by reflector surface distortion. Breadbroad model test result reveal that the maximum sidelobe level outside the 2.5 HPBW region is -30 dB or lower relative to the power.

  10. 30/20 GHz communications satellite multibeam antenna

    Science.gov (United States)

    Scott, W. G.; Luh, H. S.; Smoll, A. E.; Matthews, E. W.

    1982-01-01

    A 20 GHz downlink satellite antenna design is described. The aperture simultaneously radiates 18 fixed, 0.3 deg width pencil beams directed at 18 cities distributed over CONUS for Trunking Service. All beams use the same trunk frequency allocation for 18 reuses of the band. The same aperture also radiates six additional 0.3 deg spot beams for Customer Premises Service (CPS) for TDMA beam hopping operation to small terminals anywhere in CONUS. Each CPS beam scans one sector of CONUS and all six beams are frequency reused in a CPS band. Offset dual reflector optics are used with a feed array and multiport beam forming network (BFN). For so many frequency reuses, sidelobes per beam must be 30 to 40 dB down over CONUS. Novel dual reflector optics were devised with shaped surfaces providing low aberrations for all beam positions over CONUS (+ or - 12 BW by + or - 5 BW). Scan loss under 1 dB is calculated with nearly constant sidelobes. For each beam position, a 7-element cluster of feeds is activated in the feed array with coefficients adjusted by the BFN to maintain low sidelobes and thus high beam isolation for frequency reuse.

  11. Multibeam Satellite Frequency/Time Duality Study and Capacity Optimization

    CERN Document Server

    Lei, Jiang

    2011-01-01

    In this paper, we investigate two new candidate transmission schemes, Non-Orthogonal Frequency Reuse (NOFR) and Beam-Hoping (BH). They operate in different domains (frequency and time/space, respectively), and we want to know which domain shows overall best performance. We propose a novel formulation of the Signal-to-Interference plus Noise Ratio (SINR) which allows us to prove the frequency/time duality of these schemes. Further, we propose two novel capacity optimization approaches assuming per-beam SINR constraints in order to use the satellite resources (e.g. power and bandwidth) more efficiently. Moreover, we develop a general methodology to include technological constraints due to realistic implementations, and obtain the main factors that prevent the two technologies dual of each other in practice, and formulate the technological gap between them. The Shannon capacity (upper bound) and current state-of-the-art coding and modulations are analyzed in order to quantify the gap and to evaluate the performa...

  12. Development of Ray Tracing Algorithms for Scanning Plane and Transverse Plane Analysis for Satellite Multibeam Application

    Directory of Open Access Journals (Sweden)

    N. H. Abd Rahman

    2014-01-01

    Full Text Available Reflector antennas have been widely used in many areas. In the implementation of parabolic reflector antenna for broadcasting satellite applications, it is essential for the spacecraft antenna to provide precise contoured beam to effectively serve the required region. For this purpose, combinations of more than one beam are required. Therefore, a tool utilizing ray tracing method is developed to calculate precise off-axis beams for multibeam antenna system. In the multibeam system, each beam will be fed from different feed positions to allow the main beam to be radiated at the exact direction on the coverage area. Thus, detailed study on caustics of a parabolic reflector antenna is performed and presented in this paper, which is to investigate the behaviour of the rays and its relation to various antenna parameters. In order to produce accurate data for the analysis, the caustic behaviours are investigated in two distinctive modes: scanning plane and transverse plane. This paper presents the detailed discussions on the derivation of the ray tracing algorithms, the establishment of the equations of caustic loci, and the verification of the method through calculation of radiation pattern.

  13. An Optimal Beamforming Algorithm for Phased-Array Antennas Used in Multi-Beam Spaceborne Radiometers

    DEFF Research Database (Denmark)

    Iupikov, O. A.; Ivashina, M. V.; Pontoppidan, K.;

    2015-01-01

    Strict requirements for future spaceborne ocean missions using multi-beam radiometers call for new antenna technologies, such as digital beamforming phased arrays. In this paper, we present an optimal beamforming algorithm for phased-array antenna systems designed to operate as focal plane arrays...

  14. Power Allocation Algorithm for IDMA-based Multi-Beam Satellite Communication Systems

    Directory of Open Access Journals (Sweden)

    Gongliang Liu

    2012-08-01

    Full Text Available Rain attenuation is one of the most dominant impairment factors that degrade the performance of satellite communications at Ka band and above. In order to solve the technical bottlenecks in the existing Ka-band satellite communication schemes, the authors has introduced the emerging Interleave Division Multiple Access (IDMA technology into multi-beam satellite communication systems, and consequently, a novel power allocation algorithm is proposed for the emerging and promising system in this paper. The main goal of the proposed scheme is to provide sufficient transmission quality to as many mobiles as possible, even for the users suffering heavy rain attenuation. Analysis and simulation results show that compared to the traditional power allocation schemes, the proposed scheme can guarantee high power efficiency even in heavy rain attenuation conditions, illustrating the high efficiency of the Chip-by-Chip (CBC Multi-user Detection (MUD technique in IDMA. Furthermore, in virtue of the Signal to Interference plus Noise Ratio (SINR evolution technique, the proposed scheme can make accurate estimation of available resource on considering the effect of MUD, leading to low outage probability.

  15. Mosaic of gridded multibeam bathymetry, LiDAR bathymetry and bathymetry derived from multispectral IKONOS satellite imagery of Saipan Island, Commonwealth of Northern Maraina Islands, USA

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Gridded multibeam bathymetry is integrated with gridded LiDAR bathymetry and bathymetry derived from multispectral IKONOS satellite data. Gridded (5 m cell size)...

  16. Mosaic of gridded multibeam bathymetry, gridded LiDAR bathymetry and bathymetry derived from multispectral IKONOS satellite imagery of Tinian Island, Commonwealth of the Northern Marianas Islands, USA

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Gridded multibeam bathymetry is integrated with gridded LiDAR bathymetry and bathymetry derived from multispectral IKONOS satellite data. Gridded (5 m cell size)...

  17. 星载多波束天线设计%Design of Multi-beam Satellite Antennas

    Institute of Scientific and Technical Information of China (English)

    段玉虎

    2011-01-01

    给出了星栽多波束天线的设计方法、步骤和参数选择原则,给出了2个区域多点波束天线和赋形波束的设计实例,并用物理光学法计算了覆盖区域的天线方向图、覆盖区增益和频率复用时的同极化波束隔离.%The design method, procedure and principle of parameter choice for design of multi-beam satellite antennas are presented. Furthermore, the paper offers specific design examples of two-region multi-beam antennas and shaped beam. Finally, the radiation pattern and co-polarization isolation against gain and with frequency reuse of coverage area are calculated with physical-optics method.

  18. Advanced Communication Technology Satellite (ACTS) Multibeam Antenna On-Orbit Performance

    Science.gov (United States)

    1995-01-01

    The NASA Lewis Research Center's Advanced Communication Technology Satellite (ACTS) was launched in September 1993. ACTS introduced several new technologies, including a multibeam antenna (MBA) operating at extremely short wavelengths never before used in communications. This antenna, which has both fixed and rapidly reconfigurable high-energy spot beams (150 miles in diameter), serves users equipped with small antenna terminals. Extensive structural and thermal analyses have been performed for simulating the ACTS MBA on-orbit performance. The results show that the reflector surfaces (mainly the front subreflector), antenna support assembly, and metallic surfaces on the spacecraft body will be distorted because of the thermal effects of varying solar heating, which degrade the ACTS MBA performance. Since ACTS was launched, a number of evaluations have been performed to assess MBA performance in the space environment. For example, the on-orbit performance measurements found systematic environmental disturbances to the MBA beam pointing. These disturbances were found to be imposed by the attitude control system, antenna and spacecraft mechanical alignments, and on-orbit thermal effects. As a result, the MBA may not always exactly cover the intended service area. In addition, the on-orbit measurements showed that antenna pointing accuracy is the performance parameter most sensitive to thermal distortions on the front subreflector surface and antenna support assemblies. Several compensation approaches were tested and evaluated to restore on-orbit pointing stability. A combination of autotrack (75 percent of the time) and Earth sensor control (25 percent of the time) was found to be the best way to compensate for antenna pointing error during orbit. This approach greatly minimizes the effects of thermal distortions on antenna beam pointing.

  19. Symbol-Level Precoding with Per-antenna Power Constraints for the Multi-beam Satellite Downlink

    OpenAIRE

    Spano, Danilo; Chatzinotas, Symeon; Krause, Jens; Ottersten, Björn

    2016-01-01

    This paper tackles the problem of multi-user interference in the forward downlink channel of a multi-beam satellite system. A symbol-level precoding scheme is considered, where the data information is used, along with the channel state information, in order to exploit the multi-user interference and transform it into useful power at the receiver side. In this framework, the max-min fair problem for constructive interference is formulated and solved, under per-antenna power constraints. The co...

  20. An Optimal Beamforming Algorithm for Phased-Array Antennas Used in Multi-Beam Spaceborne Radiometers

    DEFF Research Database (Denmark)

    Iupikov, O. A.; Ivashina, M. V.; Pontoppidan, K.

    2015-01-01

    Strict requirements for future spaceborne ocean missions using multi-beam radiometers call for new antenna technologies, such as digital beamforming phased arrays. In this paper, we present an optimal beamforming algorithm for phased-array antenna systems designed to operate as focal plane arrays...... (FPA) in push-broom radiometers. This algorithm is formulated as an optimization procedure that maximizes the beam efficiency, while minimizing the side-lobe and cross-polarization power in the area of Earth, subject to a constraint on the beamformer dynamic range. The proposed algorithm is applied...

  1. Leaky wave enhanced feeds for multibeam reflectors to be used for telecom satellite based links

    NARCIS (Netherlands)

    Neto, A.; Ettorre, M.; Gerini, G.; Maagt, P. de

    2012-01-01

    The use of dielectric super-layers for shaping the radiation pattern of focal plane feeds of a multibeam reflector system is discussed. Using the super-layers, it is possible to reduce the spillover from the reflectors without increasing the dimension of each aperture. The effect has been demonstrat

  2. Calibration and performance analysis on channel mismatch of multi-beam antenna on satellites%星载多波束天线通道误差特性分析及校准

    Institute of Scientific and Technical Information of China (English)

    赵星惟; 龚文斌; 梁旭文

    2012-01-01

    针对星载多波束天线幅相误差对天线性能影响较大的问题,通过对多波束发射天线的射频通道在不同温度下的幅相特性进行试验测定,得到了通道幅相特性与温度的对应关系,发现不同通道的幅相特性与通道温度的关系曲线在给定温度区间内基本呈线性关系,且斜率基本一致,从而确定了对不同通道的幅相特性进行固定值补偿的校准策略.通过固定值补偿后,各通道的幅相特性曲线基本重合,从而消除了通道间幅相误差.进一步给出了提升温度一致性的措施,并设计了多波束发射天线的校准原理框图和校准流程图.结果表明:新的星载多波束天线幅相误差校准方法是有效的.%To solve the mismatch effect of amplitude-and-phase errors on multi-beam antenna performance , the radio frequency channel amplitude and phase errors of multi-beam transmitting antenna on satellite were experimentally measured to obtain the corresponding relations of channel amplitude-and-phase mismatch and temperature, and to compensate the mismatch. The shell temperatures are almost same after temperature stabilization, which effectively results in channel consistency. Some methods were used to improve temperature consistency. Calibration of channel is the key to guarantee the performance indexes of multi-beam antenna on satellites. The calibration principle block diagram and flow chart of multi-beam transmitting antenna were designed. The theoretical analysis and simulation results show that the proposed calibration method is effective for calibration of multi-beam antenna on satellites.

  3. Investigation of the phase stability of an X-band long pulse multibeam relativistic klystron amplifier

    Science.gov (United States)

    Liu, Zhenbang; Huang, Hua; Jin, Xiao; Lei, Lurong; Zhu, Lei; Li, Lele; Li, Shifeng; Yan, Wenkang; He, Hu

    2016-09-01

    To realize coherent high power microwave combining, an X-band long pulse multibeam relativistic klystron amplifier is designed, and the relative phase stability is investigated by three dimensions particle in cell simulation and high power microwave experiment. The simulation shows that the relative phase difference can be stabilized at gigawatt level radiation power. But the relative phase jitter increases in the experiment, then some measures are proposed to improve the stability of relative phase difference and avoid pulse shortening. A 0.98 GW radiation power with pulse duration of 160 ns is obtained in the experiment, the pulse shortening is avoided. The relative phase difference fluctuation between output microwave and input RF signal is less than ±25° in a single shot with duration of 100 ns. Then, the experiment of pulse repetition is carried out, and an output microwave with 0.98 GW radiation power at 25 Hz repetition rate is obtained. The power conversion efficiency is about 35% with pulse duration of 160 ns. The relative phase difference is less than ±30° at 25 Hz repetition rate in 100 ns.

  4. SYSTEM MODELLING OF DTH BROADCASTING AT KA BAND MULTIBEAM SATELLITE SYSTEM OVER INDIA

    Directory of Open Access Journals (Sweden)

    Swastik Sahoo

    2015-12-01

    Full Text Available A major application of satellite is broadcasting and in India this is done at Ku band. But with the increase of demand of number of channels Ku band is getting saturated. So, to satisfy this requirement an approach is to go to higher frequency band, i.e. Ka band. As India is allocated with seven fixed GEO locations, so the purpose is to calculate what is the suitable satellite position for India at Ka band, what is the best EIRP available at that position and what will be the smallest ground antenna diameter and satellite antenna diameter at Ka band. Broadcasting is done at 20GHz Ka band downlink frequency. At this frequency, as the signal will face lots of impairments during propagation, so the attenuation caused by variety of factors are discussed here. To overcome the attenuation maximum EIRP is given. The link equation is taken as a reference to calculate quality of the signal, G/T ratio and EIRP of the satellite. The extreme west region of India is being taken as earth station and after some brief calculations all the results are discussed. Out of seven allocated GEO locations, 74⁰E gives best output in terms of minimum loss & small antenna diameters.

  5. Spatial Prediction of Coastal Bathymetry Based on Multispectral Satellite Imagery and Multibeam Data

    Directory of Open Access Journals (Sweden)

    Xavier Monteys

    2015-10-01

    Full Text Available The coastal shallow water zone can be a challenging and costly environment in which to acquire bathymetry and other oceanographic data using traditional survey methods. Much of the coastal shallow water zone worldwide remains unmapped using recent techniques and is, therefore, poorly understood. Optical satellite imagery is proving to be a useful tool in predicting water depth in coastal zones, particularly in conjunction with other standard datasets, though its quality and accuracy remains largely unconstrained. A common challenge in any prediction study is to choose a small but representative group of predictors, one of which can be determined as the best. In this respect, exploratory analyses are used to guide the make-up of this group, where we choose to compare a basic non-spatial model versus four spatial alternatives, each catering for a variety of spatial effects. Using one instance of RapidEye satellite imagery, we show that all four spatial models show better adjustments than the non-spatial model in the water depth predictions, with the best predictor yielding a correlation coefficient of actual versus predicted at 0.985. All five predictors also factor in the influence of bottom type in explaining water depth variation. However, the prediction ranges are too large to be used in high accuracy bathymetry products such as navigation charts; nevertheless, they are considered beneficial in a variety of other applications in sensitive disciplines such as environmental monitoring, seabed mapping, or coastal zone management.

  6. Low Complexity Multiuser Detection Algorithm for Multi-Beam Satellite Systems

    Institute of Scientific and Technical Information of China (English)

    Yang Wang; Danfeng Zhao; Xi Liao

    2015-01-01

    The minimum mean square error⁃successive interference cancellation ( MMSE⁃SIC ) multiuser detection algorithm has high complexity and long processing latency. A multiuser detection algorithm is proposed for multi⁃beam satellite systems in order to decrease the complexity and latency. The spot beams are grouped base on the distance between them in the proposed algorithm. Some groups are detected in parallel after a crucial group⁃wise interference cancellation. Furthermore, the multi⁃stage structure is introduced to improve the performance. Simulation results show that the proposed algorithm can achieve better performance with less complexity compared with the existing group detection algorithm. Moreover, the proposed algorithm using one stage can reduce the complexity over the fast MMSE⁃SIC and existing group detection algorithm by 9% and 20�9%. The processing latency is reduced significantly compared with the MMSE⁃SIC.

  7. Design on configurations of multi-beam antenna of LEO communication satellite%LEO通信卫星多波束天线构型方案设计

    Institute of Scientific and Technical Information of China (English)

    赵星惟; 吕源; 刘会杰; 梁旭文

    2011-01-01

    We present systematic analysis and planning of multi-beam antenna based on the features of LEO communication satellite. First, the reasons for adopting multi-beam antenna system are analyzed. Calculations of system parameters within the satellite coverage range are performed based on 7-beam equal-coverage-area scheme. System parameters, like beam width and beam angle, are given. Then, the scheme of array antenna is elaborated and analyzed. Some beamforming and multiplexing schemes are designed and analyzed.%针对低轨道(LEO)通信卫星的特点,进行星载多波束天线的系统级分析和规划.首先,对天线体制选择多波束天线的原因进行了论述.基于卫星覆盖范围的指标,进行了7波束等覆盖面积方案下波束指标的计算,给出了波束宽度、夹角等系统指标.然后对阵列天线方案进行了详细论述.最后对波束形成方案以及复用方案进行了设计和分析.

  8. Phased Array Transmit Antenna for a Satellite

    Science.gov (United States)

    Huggins, R. W.; Heisen, P. T.; Miller, G. E.; McMeen, D. J.; Perko, K. L.

    1999-01-01

    Active phased array antennas with electronically scanned beams offer advantages over high gain parabolic dish antennas currently used on spacecraft. Benefits include the elimination of deployable structures, no moving parts, and no torque disturbances that moving antennas impart to the spacecraft. The latter results in the conservation of spacecraft power, and the ability to take precision optical data while transmitting data. Such an antenna has been built under a contract from NASA Goddard Space Flight Center for the New Millennium Program EO- 1 satellite where it will act as the primary highspeed scientific data communication link. The antenna operates at X-band, has an integral controller and power conditioner, communicates with the spacecraft over a 1773 optical data bus, and is space qualified for low earth orbit (705 Km altitude). The nominal mission length is one year, and the operational requirement is for one 10 minute transmission a day over Spitsbergen, Norway. Details of the antenna and its performance will be described in the following paper.

  9. Optimizing Satellite Communications With Adaptive and Phased Array Antennas

    Science.gov (United States)

    Ingram, Mary Ann; Romanofsky, Robert; Lee, Richard Q.; Miranda, Felix; Popovic, Zoya; Langley, John; Barott, William C.; Ahmed, M. Usman; Mandl, Dan

    2004-01-01

    A new adaptive antenna array architecture for low-earth-orbiting satellite ground stations is being investigated. These ground stations are intended to have no moving parts and could potentially be operated in populated areas, where terrestrial interference is likely. The architecture includes multiple, moderately directive phased arrays. The phased arrays, each steered in the approximate direction of the satellite, are adaptively combined to enhance the Signal-to-Noise and Interference-Ratio (SNIR) of the desired satellite. The size of each phased array is to be traded-off with the number of phased arrays, to optimize cost, while meeting a bit-error-rate threshold. Also, two phased array architectures are being prototyped: a spacefed lens array and a reflect-array. If two co-channel satellites are in the field of view of the phased arrays, then multi-user detection techniques may enable simultaneous demodulation of the satellite signals, also known as Space Division Multiple Access (SDMA). We report on Phase I of the project, in which fixed directional elements are adaptively combined in a prototype to demodulate the S-band downlink of the EO-1 satellite, which is part of the New Millennium Program at NASA.

  10. EQUIVALENT BASELINE AND INTERFEROMETRIC PHASE OF CLUSTER SATELLITE SAR

    Institute of Scientific and Technical Information of China (English)

    Gong Min; Zhang Chuanwu; Huang Shunji

    2005-01-01

    The change of the equivalent baseline and interferometric phase of cluster SAR satellites is analyzed when the constellation circles around the Earth and the satellites rotate around the center at the same time. The letter provides assessment of baseline error and phase error which influence the precision of height measurement in the across-track interferometric mode. The mathematical model of cluster satellite movement is built, simulation analyses and the curve of height error are presented. The simulation results show that height measurement error can be compensated by the formulae derived in this letter, therefore, the Digital Elevation Models (DEM's) are recovered accurately.

  11. Multibeam Antennas Array Pattern Synthesis Using a Variational Method

    Directory of Open Access Journals (Sweden)

    F. T. Bendimerad

    2007-06-01

    Full Text Available In this paper a new method is described for multibeam antennas synthesis where both the amplitude and phase of each radiating element is a design variable. The developed optimization method made possible to solve the synthesis problem and to answer all the constraints imposed by the radiation pattern. Two approaches for visualizing satellite antenna radiation patterns are presented. Gain-level contours drawn over a geographical map gives clearest qualitative information. A three-dimensional (3D surface plot displays the qualitative shape of the radiation pattern more naturally. The simulations results have shown power, precision and speed of the variational method with respect to the constraints imposed on radiation pattern of the of multibeam antennas network.

  12. Demonstration Results of the Triband, Multi-Beam Airborne Telemetry Phased Array (AirPA) System

    Science.gov (United States)

    2015-03-01

    Phased Array, antenna , digital beam-forming, beamforming, DBF, L-band, S-band, C-band, CTEIP, NAVAIR 16. SECURITY CLASSIFICATION OF...Outback BER After the flight test completed, the AirPA system was reconfigured to support the L-band flight test, Flight 171. At the request of the

  13. The ACTS multibeam antenna

    Science.gov (United States)

    Regier, Frank A.

    1992-01-01

    The Advanced Communications Technology Satellite (ACTS) to be launched in 1993 is briefly introduced. Its multibeam antenna, consisting of electrically similar 30 GHz receive and 20 GHz transmit offset Cassegrain systems, both utilizing orthogonal polarizations, is described. Dual polarization is achieved by using one feed assembly for each polarization in conjunction with nested front and back subreflectors, the gridded front subreflector acting as a window for one polarization and a reflector for the other. The antennas produce spot beams with approximately 0.3 degree beamwidth and gains of approximately 50 dbi. High surface accuracy and high edge taper produce low sidelobe levels and high cross-polarization isolation. A brief description is given of several Ka-band components fabricated for ACTS. These include multiflare antenna feedhorns, beam-forming networks utilizing latching ferrite waveguide switches, a 30 GHz HEMT low-noise amplifier and a 20 GHz TWT power amplifier.

  14. The ACTS multibeam antenna

    Science.gov (United States)

    Regier, Frank A.

    1992-06-01

    The Advanced Communications Technology Satellite (ACTS) to be launched in 1993 is briefly introduced. Its multibeam antenna, consisting of electrically similar 30 GHz receive and 20 GHz transmit offset Cassegrain systems, both utilizing orthogonal polarizations, is described. Dual polarization is achieved by using one feed assembly for each polarization in conjunction with nested front and back subreflectors, the gridded front subreflector acting as a window for one polarization and a reflector for the other. The antennas produce spot beams with approximately 0.3 degree beamwidth and gains of approximately 50 dbi. High surface accuracy and high edge taper produce low sidelobe levels and high cross-polarization isolation. A brief description is given of several Ka-band components fabricated for ACTS. These include multiflare antenna feedhorns, beam-forming networks utilizing latching ferrite waveguide switches, a 30 GHz HEMT low-noise amplifier and a 20 GHz TWT power amplifier.

  15. Phase control system concepts and simulations. [solar power satellite system

    Science.gov (United States)

    Lindsay, V. C.

    1980-01-01

    A phase control system concept for a solar power satellite is proposed which partitions the system into three major levels. The first level of phase control consists of a reference phase distribution system implemented in the form of phase distribution tree structure. The major purpose of the tree structure is to electronically compensate for the phase shift due to the transition path lengths from the center of the spacetenna to each phase control center located in each subarray. In the reference system, this is accomplished using the master slave returnable timing system technique. The second level of phase control consists of the beam steering and microwave power generating system which houses the power transponders. This transponder consists of a set of phase conjugation multipliers driven by the reference phase distribution system output and the output of a pilot spread spectrum receiver which accepts the received pilot via a diplexer connected to a separate receive horn or the subarray itself. The output of the phase conjugation circuits serve as inputs to the third level of the phase control system. The third level of phase control is associated with maintaining an equal and constant phase shift through the microwave power amplifier devices while minimizing the associated phase noise effects on the generated power beam. This is accomplished by providing a phase locked loop around each high power amplifier.

  16. Estimation of satellite antenna phase center offsets for Galileo

    Science.gov (United States)

    Steigenberger, P.; Fritsche, M.; Dach, R.; Schmid, R.; Montenbruck, O.; Uhlemann, M.; Prange, L.

    2016-08-01

    Satellite antenna phase center offsets for the Galileo In-Orbit Validation (IOV) and Full Operational Capability (FOC) satellites are estimated by two different analysis centers based on tracking data of a global GNSS network. The mean x- and y-offsets could be determined with a precision of a few centimeters. However, daily estimates of the x-offsets of the IOV satellites show pronounced systematic effects with a peak-to-peak amplitude of up to 70 cm that depend on the orbit model and the elevation of the Sun above the orbital plane. For the IOV y-offsets, no dependence on the orbit model exists but the scatter strongly depends on the elevation of the Sun above the orbital plane. In general, these systematic effects are significantly smaller for the FOC satellites. The z-offsets of the two analysis centers agree within the 10-15 cm level, and the time series do not show systematic effects. The application of an averaged Galileo satellite antenna model obtained from the two solutions results in a reduction of orbit day boundary discontinuities by up to one third—even if an independent software package is used.

  17. Considerations of digital phase modulation for narrowband satellite mobile communication

    Science.gov (United States)

    Grythe, Knut

    1990-01-01

    The Inmarsat-M system for mobile satellite communication is specified as a frequency division multiple access (FDMA) system, applying Offset Quadrature Phase Shift Keying (QPSK) for transmitting 8 kbit/sec in 10 kHz user channel bandwidth. We consider Digital Phase Modulation (DPM) as an alternative modulation format for INMARSAT-M. DPM is similar to Continuous Phase Modulation (CPM) except that DPM has a finite memory in the premodular filter with a continuous varying modulation index. It is shown that DPM with 64 states in the VA obtains a lower bit error rate (BER). Results for a 5 kHz system, with the same 8 kbit/sec transmitted bitstream, is also presented.

  18. Multibeam Bathymetry Database (MBBDB)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Originally designed for military use, the multibeam echosounder has proved very useful for nautical charting, oceanographic research and modeling, habitat...

  19. An algorithm for signal processing in multibeam antenna arrays

    Science.gov (United States)

    Danilevskii, L. N.; Domanov, Iu. A.; Korobko, O. V.

    1980-09-01

    A signal processing method for multibeam antenna arrays is presented which can be used to effectively reduce discrete-phasing sidelobes. Calculations of an 11-element array are presented as an example.

  20. Multi-Beam Optical Tweezers

    OpenAIRE

    Glückstad, Jesper; Eriksen, Rene Lynge; Hanson, Steen Grüner

    2003-01-01

    A set of multi-beam electromagnetic tweezers is provided comprising a multi-beam generator for emission of a plurality of electromagnetic beams, at least some of the electromagnetic beams intersecting each other, or, having an individually controlled polarization whereby the position and/or angular orientation of a plurality of micro-objects may be individually controlled.A set of multi-beam electromagnetic tweezers is provided comprising a multi-beam generator for emission of a plurality of ...

  1. Conformal phased array with beam forming for airborne satellite communication

    NARCIS (Netherlands)

    Schippers, H.; Verpoorte, J.; Jorna, P.; Hulzinga, A.; Meijerink, A.; Roeloffzen, C.G.H.; Heideman, R.G.; Leinse, A.; Wintels, M.

    2008-01-01

    For enhanced communication on board of aircraft novel antenna systems with broadband satellite-based capabilities are required. The installation of such systems on board of aircraft requires the development of a very low-profile aircraft antenna, which can point to satellites anywhere in the upper h

  2. Micro-Satellite Attitude Determination Using GPS Carrier Phases

    Institute of Scientific and Technical Information of China (English)

    He Xiu-feng; Ling Keck-voon

    2003-01-01

    GPS is an attractive attitude sensor for micro-satellites due to small package and advantage for cost savings. However, the major difficulty in attitude determination for a micro-satellite is that baseline lengths are short (less than a meter) . Thus , to obtain precise accuracy of attitudes for a micro-satellite, the algorithm selection and error source calibration are important. In this paper, a technique based on the attitude cost function is proposed. To verify the method proposed, the experiments have been conducted. The results indicate that attitude errors are less than 1 deg.

  3. Designing the next phase domestic satellites - A step to communication satellites as intelligent network nodes

    Science.gov (United States)

    Majus, J.

    1982-09-01

    Applications of satellite systems for telecommunication networks are discussed in terms of harmonizing the satellite capabilities with ground-based equipment, and design for the satellites are discussed. Modern network services are becoming increasingly digitized and use optic fiber switching and information transfer. Spaceborne nodes can be used for telephony, television, packet switching, leased lines, and teletex, with reserved sectors for point-to-point communications. Space systems are capable of 100% coverage, while terrestrial systems frequently have utilization rates near 5%, implying that demand-oriented satellite expansion of local systems is the suitable methodology. Technological requirements are explored, including exclusive use of digital processing, flexible flow rates, signal transmission times, and short time availability.

  4. SPS-ALPHA: The First Practical Solar Power Satellite via Arbitrarily Large PHased Array Project

    Data.gov (United States)

    National Aeronautics and Space Administration — SPS-ALPHA (Solar Power Satellite via Arbitrarily Large Phased Array) is a novel, bio-mimetic approach to the challenge of space solar power. If successful, this...

  5. Automatic phase control in solar power satellite systems

    Science.gov (United States)

    Lindsey, W. C.; Kantak, A. V.

    1978-01-01

    Various approaches to the problem of generating, maintaining and distributing a coherent, reference phase signal over a large area are suggested, mathematically modeled and analyzed with respect to their ability to minimize: phase build-up, beam diffusion and beam steering phase jitter, cable length, and maximize power transfer efficiency. In addition, phase control configurations are suggested which alleviate the need for layout symmetry.

  6. Multi-Beam Optical Tweezers

    DEFF Research Database (Denmark)

    2003-01-01

    A set of multi-beam electromagnetic tweezers is provided comprising a multi-beam generator for emission of a plurality of electromagnetic beams, at least some of the electromagnetic beams intersecting each other, or, having an individually controlled polarization whereby the position and/or angular...... orientation of a plurality of micro-objects may be individually controlled.A set of multi-beam electromagnetic tweezers is provided comprising a multi-beam generator for emission of a plurality of electromagnetic beams, at least some of the electromagnetic beams intersecting each other, or, having...

  7. Solid-state retrodirective phased array concepts for microwave power transmission from Solar Power Satellite

    Science.gov (United States)

    Schroeder, K. G.; Petroff, I. K.

    1980-01-01

    Two prototype solid-state phased array systems concepts for potential use in the Solar Power Satellite are described. In both concepts, the beam is centered on the rectenna by means of phase conjugation of a pilot signal emanating from the ground. Also discussed is on-going solid-state amplifier development.

  8. Phased Antenna Array for Global Navigation Satellite System Signals

    Science.gov (United States)

    Turbiner, Dmitry (Inventor)

    2015-01-01

    Systems and methods for phased array antennas are described. Supports for phased array antennas can be constructed by 3D printing. The array elements and combiner network can be constructed by conducting wire. Different parameters of the antenna, like the gain and directivity, can be controlled by selection of the appropriate design, and by electrical steering. Phased array antennas may be used for radio occultation measurements.

  9. Phase Compensation Sensor for Ranging Consistency in Inter-Satellite Links of Navigation Constellation

    Science.gov (United States)

    Meng, Zhijun; Yang, Jun; Guo, Xiye; Hu, Mei

    2017-01-01

    The performance of the global navigation satellite system (GNSS) can be enhanced significantly by introducing the inter-satellite links (ISL) of a navigation constellation. In particular, the improvement of the position, velocity, and time accuracy, and the realization of autonomous functions require the ISL distance measurement data as the original input. For building a high-performance ISL, the ranging consistency between navigation satellites becomes a crucial problem to be addressed. Considering the frequency aging drift and the relativistic effect of the navigation satellite, the frequency and phase adjustment (FPA) instructions for the 10.23 MHz must be injected from the ground station to ensure the time synchronization of the navigation constellation. Moreover, the uncertainty of the initial phase each time the onboard clock equipment boots also results in a pseudo-range offset. In this Ref., we focus on the influence of the frequency and phase characteristics of the onboard clock equipment on the ranging consistency of the ISL and propose a phase compensation sensor design method for the phase offset. The simulation and experimental results show that the proposed method not only realized a phase compensation for the pseudo-range jitter, but, when the 1 PPS (1 pulse per second) falls in the 10.23 MHz skip area, also overcomes the problem of compensating the ambiguous phase by directly tracking the 10.23 MHz to ensure consistency in the ranging. PMID:28245572

  10. Spaceborne GPS receiver antenna phase center offset and variation estimation for the Shiyan 3 satellite

    Directory of Open Access Journals (Sweden)

    Gu Defeng

    2016-10-01

    Full Text Available In determining the orbits of low Earth orbit (LEO satellites using spaceborne GPS, the errors caused by receiver antenna phase center offset (PCO and phase center variations (PCVs are gradually becoming a major limiting factor for continued improvements to accuracy. Shiyan 3, a small satellite mission for space technology experimentation and climate exploration, was developed by China and launched on November 5, 2008. The dual-frequency GPS receiver payload delivers 1 Hz data and provides the basis for precise orbit determination within the range of a few centimeters. The antenna PCO and PCV error characteristics and the principles influencing orbit determination are analyzed. The feasibility of PCO and PCV estimation and compensation in different directions is demonstrated through simulation and in-flight tests. The values of receiver antenna PCO and PCVs for Gravity Recovery and Climate Experiment (GRACE and Shiyan 3 satellites are estimated from one month of data. A large and stable antenna PCO error, reaching up to 10.34 cm in the z-direction, is found with the Shiyan 3 satellite. The PCVs on the Shiyan 3 satellite are estimated and reach up to 3.0 cm, which is slightly larger than that of GRACE satellites. Orbit validation clearly improved with independent k-band ranging (KBR and satellite laser ranging (SLR measurements. For GRACE satellites, the average root mean square (RMS of KBR residuals improved from 1.01 cm to 0.88 cm. For the Shiyan 3 satellite, the average RMS of SLR residuals improved from 4.95 cm to 4.06 cm.

  11. Spaceborne GPS receiver antenna phase center offset and variation estimation for the Shiyan 3 satellite

    Institute of Scientific and Technical Information of China (English)

    Gu Defeng; Lai Yuwang; Liu Junhong; Ju Bing; Tu Jia

    2016-01-01

    In determining the orbits of low Earth orbit (LEO) satellites using spaceborne GPS, the errors caused by receiver antenna phase center offset (PCO) and phase center variations (PCVs) are gradually becoming a major limiting factor for continued improvements to accuracy. Shiyan 3, a small satellite mission for space technology experimentation and climate exploration, was developed by China and launched on November 5, 2008. The dual-frequency GPS receiver payload delivers 1 Hz data and provides the basis for precise orbit determination within the range of a few centime-ters. The antenna PCO and PCV error characteristics and the principles influencing orbit determi-nation are analyzed. The feasibility of PCO and PCV estimation and compensation in different directions is demonstrated through simulation and in-flight tests. The values of receiver antenna PCO and PCVs for Gravity Recovery and Climate Experiment (GRACE) and Shiyan 3 satellites are estimated from one month of data. A large and stable antenna PCO error, reaching up to 10.34 cm in the z-direction, is found with the Shiyan 3 satellite. The PCVs on the Shiyan 3 satellite are estimated and reach up to 3.0 cm, which is slightly larger than that of GRACE satellites. Orbit validation clearly improved with independent k-band ranging (KBR) and satellite laser ranging (SLR) measurements. For GRACE satellites, the average root mean square (RMS) of KBR resid-uals improved from 1.01 cm to 0.88 cm. For the Shiyan 3 satellite, the average RMS of SLR resid-uals improved from 4.95 cm to 4.06 cm.

  12. Analysis of L5 phase variations in GPS IIF satellites by the raw observation PPP approach

    Science.gov (United States)

    Liu, Sha; Becker, Matthias

    2015-04-01

    GPS modernization along with Glonass modernization and the emerging Galileo and Compass system has been highly anticipated by every GNSS user since several years. The third civilian L5 signal transmitted by the modernized GPS satellites brings us to the GNSS multi-frequency era. The first GPS IIF satellite was launched in May 2010, until now there are eight block IIF satellites in service and the remaining four IIF satellites are planned to be launched by 2016. The introduction of the third frequency to GPS and the usage of advanced atomic clocks not only provide the users more possibilities but also enable higher positioning accuracy. Nevertheless phase variations are found on the new L5 observation of GPS SVN62. Further investigations suggest that the variations of this satellite are strongly dependent on the satellite inner temperature variation caused by sun illumination. Besides achieving precise positioning accuracy, PPP is also frequently used as a tool to analyze and evaluate various GNSS errors, for instance, tropospheric delays and receiver clock errors. Other than with differential GNSS, it is possible to separate different errors and to identify the error sources with PPP. Conventional PPP is based on the ionosphere-free linear combination, in order to eliminate the first-order ionospheric delays. However only dual frequencies can be used to build ionosphere-free linear combination, which leads to the waste of the information on the third frequency. Furthermore, the frequency dependent errors can not be separated and traced. A new PPP approach that avoids using any linear combination is proposed recently, which is called the raw observation PPP. One advantage of the raw observation PPP approach is that data of all frequencies and all GNSS systems can be jointly used. In addition, the frequency dependent errors are possible to be separated, identified and analyzed. In this paper the raw observation PPP is utilized to analyze the phase variations on L5

  13. Phase Compensation Sensor for Ranging Consistency in Inter-Satellite Links of Navigation Constellation.

    Science.gov (United States)

    Meng, Zhijun; Yang, Jun; Guo, Xiye; Hu, Mei

    2017-02-24

    Theperformanceoftheglobalnavigationsatellitesystem(GNSS)canbeenhancedsignificantly by introducing the inter-satellite links (ISL) of a navigation constellation. In particular, the improvement of the position, velocity, and time accuracy, and the realization of autonomous functions require the ISL distance measurement data as the original input. For building a high-performance ISL, the ranging consistency between navigation satellites becomes a crucial problem to be addressed. Considering the frequency aging drift and the relativistic effect of the navigation satellite, the frequency and phase adjustment (FPA) instructions for the 10.23 MHz must be injected from the ground station to ensure the time synchronization of the navigation constellation. Moreover, the uncertainty of the initial phase each time the onboard clock equipment boots also results in a pseudo-range offset. In this Ref., we focus on the influence of the frequency and phase characteristics of the onboard clock equipment on the ranging consistency of the ISL and propose a phase compensation sensor design method for the phase offset. The simulation and experimental results show that the proposed method not only realized a phase compensation for the pseudo-range jitter, but, when the 1 PPS (1 pulse per second) falls in the 10.23 MHz skip area, also overcomes the problem of compensating the ambiguous phase by directly tracking the 10.23 MHz to ensure consistency in the ranging.

  14. Trans-Pacific HDR Satellite Communications Experiment Phase-2 Project Plan and Experimental Network

    Science.gov (United States)

    Hsu, Eddie; Kadowaki, Naoto; Yoshimura, Naoko; Takahashi, Takashi; Yoshikawa, Makoto; Bergman, Larry; Bhasin, Kul

    2000-01-01

    The trans-Pacific high data rate (TP-HDR) satellite communications experiment was proposed at the Japan-U.S. Cooperation in Space (JUCS) Program Workshop held in Hawaii in 1993 and remote high definition video post-production was demonstrated as the first phase trial. ATM-based 45 Mbps trans-Pacific link was established in the first phase, and the following experiments with 155 Mbps was planned as the phase 2. This paper describes the experimental network configuration and project plan of TP-HDR experiment phase 2. Additional information is provided in the original.

  15. AFSC/ABL: Multibeam Database

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Seafloor habitat maps have been created using high resolution multibeam sonar with co-registered backscatter at various locations throughout the Alaska Region. Most...

  16. Positioning reduction in the real-time phase of Chang'E-2 satellite

    Science.gov (United States)

    Li, JinLing; Liu, Li; Zheng, WeiMin; Sun, ZhongMiao

    2012-02-01

    The precision of VLBI tracking delays and the positioning reduction results during the real-time tracking phase of the Chang'E-2 satellite are statistically analyzed. The application of the positioning reduction to the real-time monitoring of pivotal arcs of the Chang'E-2 satellite is discussed. The technical specifications of the tests of tracking and control systems in X-band are estimated and evaluated via the positioning reduction method. Useful methodology and software are prepared and practical experience in engineering and technology is accumulated for the follow-up lunar and deep space explorations of China.

  17. Multibeam fiber laser cutting

    DEFF Research Database (Denmark)

    Olsen, Flemming Ove; Hansen, Klaus Schütt; Nielsen, Jakob Skov

    2009-01-01

    The appearance of the high power high brilliance fiber laser has opened for new possibilities in laser materials processing. In laser cutting this laser has demonstrated high cutting performance compared to the dominating Cutting laser, the CO2 laser. However, quality problems in fiber-laser...... cutting have until now limited its application to metal cutting. In this paper the first results of proof-of-principle Studies applying a new approach (patent pending) for laser cutting with high brightness and short wavelength lasers will be presented. In the approach, multibeam patterns are applied...... to control the melt flow out of the cut kerf resulting in improved cut quality in metal cutting. The beam patterns in this study are created by splitting up beams from two single mode fiber lasers and combining these beams into a pattern in the cut kerf. The results are obtained with a total of 550 W...

  18. Turbulent phase noise on asymmetric two-way ground-satellite coherent optical links

    Science.gov (United States)

    Robert, Clélia; Conan, Jean-Marc; Wolf, Peter

    2015-10-01

    Bidirectional ground-satellite laser links suffer from turbulence-induced scintillation and phase distortion. We study how turbulence impacts on coherent detection capacity and on the associated phase noise that restricts clock transfer precision. We evaluate the capacity to obtain a two-way cancellation of atmospheric effects despite the asymmetry between up and down link that limits the link reciprocity. For ground-satellite links, the asymmetry is induced by point-ahead angle and possibly the use, for the ground terminal, of different transceiver diameters, in reception and emission. The quantitative analysis is obtained thanks to refined end-to-end simulations under realistic turbulence and wind conditions as well as satellite cinematic. Simulations make use of the reciprocity principle to estimate both down and up link performance from wave-optics propagation of descending plane waves. These temporally resolved simulations allow characterising the coherent detection in terms of time series of heterodyne efficiency for different system parameters. We show Tip/Tilt correction on ground is mandatory at reception for the down link and as a pre-compensation of the up link. Good correlation between up and down phase noise is obtained even with asymmetric apertures of the ground transceiver and in spite of pointing ahead angle. The reduction to less than 1 rad2 of the two-way differential phase noise is very promising for clock transfer.

  19. 新型宽带数字多波束相控阵天线设计*%Design of a Novel Wideband Digital Multi-beam Phased Array Antenna

    Institute of Scientific and Technical Information of China (English)

    任燕飞; 张云; 曾浩; 郝黎宏; 唐洪军

    2013-01-01

    With the increasing numbers of beamforming,the weight,size,power consumption of traditional digi-tal multi-beam phased array antennas may increase significantly,and the system′s basic reliability will decrease significantly. Based on software radio theory,a new method is presented. Superheterodyne is used to realize wideband signal frequency changing,and A/D or D/A converter of signals is realized in instantaneous band-width simultaneously.According to the azimuth angle,pitch angle and frequence supported by series port,the multi-beam is formed in the baseband. An S-band digital multi-beam phased array antenna with 100 MHz in-stantaneous bandwidth is designed. The experimental results show that the T/R antennas can form three inde-pendent beams simultaneously. In the azimuthal omnidirectional scanning range of pitch angle 0°~70°,the EIRP is not less than 40 dBm,and G/T is not less than -20 dB/K. The design can retrench a lot of hardware devices,and reduce the complexity of the system.%  传统相控阵天线系统为实现多波束,在重量、体积、功耗等方面会有明显的增加,系统的基本可靠性也显著降低。基于软件无线电思想,利用超外差结构实现宽带信号变频,并对瞬时带宽内的信号同时进行模/数或数/模变换,再根据串口提供的每个波束方位、俯仰和频率等信息,在基带实现数字多波束形成。设计了一套S频段、瞬时宽带100 MHz的数字多波束相控阵天线系统。测试结果表明,该天线可收发同时形成3个独立波束,每个波束在俯仰面0°~70°、方位面全向的扫描范围内实现EIRP值不小于40 dBm,G/T值不小于-20 dB/K的优良指标。该设计可以有效提高系统灵活性,降低系统的复杂度。

  20. Demonstration of Two-Way Extremely High Frequency (EHF) Satellite Communication (SATCOM) Using Submarine-Survivable Phased Arrays

    Science.gov (United States)

    2009-01-01

    successfully using both the Military Strategic and Tactical Relay (MILSTAR) and Ultra High Frequency Follow-On ( UFO ) military satellites. The antennas...a Navy-qualified submarine FOT and High Power Amplifier (HPA) system, toward a MILSTAR or UFO EHF satellite. FULL-DUPLEX STATIC TESTING...both the K & Q band phased arrays. Both the MILSTAR and UFO satellites were used for this testing, based on availability. Using the Type 8 Mod 3

  1. Consistent Long-Time Series of GPS Satellite Antenna Phase Center Corrections

    Science.gov (United States)

    Steigenberger, P.; Schmid, R.; Rothacher, M.

    2004-12-01

    The current IGS processing strategy disregards satellite antenna phase center variations (pcvs) depending on the nadir angle and applies block-specific phase center offsets only. However, the transition from relative to absolute receiver antenna corrections presently under discussion necessitates the consideration of satellite antenna pcvs. Moreover, studies of several groups have shown that the offsets are not homogeneous within a satellite block. Manufacturer specifications seem to confirm this assumption. In order to get best possible antenna corrections, consistent ten-year time series (1994-2004) of satellite-specific pcvs and offsets were generated. This challenging effort became possible as part of the reprocessing of a global GPS network currently performed by the Technical Universities of Munich and Dresden. The data of about 160 stations since the official start of the IGS in 1994 have been reprocessed, as today's GPS time series are mostly inhomogeneous and inconsistent due to continuous improvements in the processing strategies and modeling of global GPS solutions. An analysis of the signals contained in the time series of the phase center offsets demonstrates amplitudes on the decimeter level, at least one order of magnitude worse than the desired accuracy. The periods partly arise from the GPS orbit configuration, as the orientation of the orbit planes with regard to the inertial system repeats after about 350 days due to the rotation of the ascending nodes. In addition, the rms values of the X- and Y-offsets show a high correlation with the angle between the orbit plane and the direction to the sun. The time series of the pcvs mainly point at the correlation with the global terrestrial scale. Solutions with relative and absolute phase center corrections, with block- and satellite-specific satellite antenna corrections demonstrate the effect of this parameter group on other global GPS parameters such as the terrestrial scale, station velocities, the

  2. Advanced two-way satellite frequency transfer by carrier-phase and carrier-frequency measurements

    Science.gov (United States)

    Fujieda, Miho; Gotoh, Tadahiro; Amagai, Jun

    2016-06-01

    Carrier-phase measurement is one of the ways to improve the measurement resolution of two-way satellite frequency transfer. We introduce two possible methods for carrier-phase measurement: direct carrier-phase detection identified by Two-Way Carrier-Phase (TWCP) and the use of carrier-frequency information identified by Two-Way Carrier Frequency (TWCF). We performed the former using an arbitrary waveform generator and an analog-to-digital sampler and the latter using a conventional modem. The TWCF measurement using the modem had a resolution of 10-13 and the result agreed with that obtained by GPS carrier-phase frequency transfer in a 1500 km baseline. The measurement accuracy may have been limited by the poor frequency resolution of the modem; however, the TWCF measurement was able to improve the stability of conventional two-way satellite frequency transfer. Additionally, we show that the TWCP measurement system has the potential to achieve a frequency stability of 10-17.

  3. Design for the Assessment and Policy Analysis of the Education Satellite Communications Demonstration. Phase 2 Final Report.

    Science.gov (United States)

    Syracuse Univ. Research Corp., NY. Educational Policy Research Center.

    The overall goal of the Education Satellite Communications Demonstration is to design a framework for the analysis of the potential utility of satellites to education in this country. Within this framework, Phase 2 sought to identify research which would be clearly related to educational goals that might be worthy of attainment. The entire…

  4. Phase Error Modeling and Its Impact on Precise Orbit Determination of GRACE Satellites

    Directory of Open Access Journals (Sweden)

    Jia Tu

    2012-01-01

    Full Text Available Limiting factors for the precise orbit determination (POD of low-earth orbit (LEO satellite using dual-frequency GPS are nowadays mainly encountered with the in-flight phase error modeling. The phase error is modeled as a systematic and a random component each depending on the direction of GPS signal reception. The systematic part and standard deviation of random part in phase error model are, respectively, estimated by bin-wise mean and standard deviation values of phase postfit residuals computed by orbit determination. By removing the systematic component and adjusting the weight of phase observation data according to standard deviation of random component, the orbit can be further improved by POD approach. The GRACE data of 1–31 January 2006 are processed, and three types of orbit solutions, POD without phase error model correction, POD with mean value correction of phase error model, and POD with phase error model correction, are obtained. The three-dimensional (3D orbit improvements derived from phase error model correction are 0.0153 m for GRACE A and 0.0131 m for GRACE B, and the 3D influences arisen from random part of phase error model are 0.0068 m and 0.0075 m for GRACE A and GRACE B, respectively. Thus the random part of phase error model cannot be neglected for POD. It is also demonstrated by phase postfit residual analysis, orbit comparison with JPL precise science orbit, and orbit validation with KBR data that the results derived from POD with phase error model correction are better than another two types of orbit solutions generated in this paper.

  5. Berry phases and profiles of line wings and rainbow satellites induced by optical collisions

    Science.gov (United States)

    Ciuryło, R.; Szudy, J.; Baylis, W. E.

    2015-09-01

    The concept of Berry phase is included in an analysis of the intensity distribution in far wings of pressure-broadened spectral lines emitted or absorbed by atoms placed in an external cone-rotating electric field. Particular attention is focused on frequency regions where rainbow satellite bands appear. A classical-path treatment that employs the time-dependent Schrödinger equation is used to derive an expression for the line shape, and it uses a dipole transition moment calculated with quasimolecular wave functions given by the Berry version of the adiabatic approximation. It is found that in the presence of an external rotating electric field, the intensity distribution in far wings can be expressed in terms of the universal line shape function of the unified Franck-Condon theory once energy shifts due to Stark and Berry effects are taken into account. We show that the influence of Berry phase in the profiles of the far wings can be manifested either in the form of deviations of observed profiles from the quasistatic distribution or the appearance of additional features in the vicinity of the maximum of the rainbow satellite band. As an example, the modification of the rainbow satellite at 162.3 nm in the red wing of the self-broadened Lyman-α line of hydrogen, caused by an external rotating electric field, is considered.

  6. Phase calibration of the EISCAT Svalbard Radar interferometer using optical satellite signatures

    Directory of Open Access Journals (Sweden)

    J. M. Sullivan

    2006-09-01

    Full Text Available The link between natural ion-line enhancements in radar spectra and auroral activity has been the subject of recent studies but conclusions have been limited by the spatial and temporal resolution previously available. The next challenge is to use shorter sub-second integration times in combination with interferometric programmes to resolve spatial structure within the main radar beam, and so relate enhanced filaments to individual auroral rays. This paper presents initial studies of a technique, using optical and spectral satellite signatures, to calibrate the received phase of a signal with the position of the scattering source along the interferometric baseline of the EISCAT Svalbard Radar. It is shown that a consistent relationship can be found only if the satellite passage through the phase fringes is adjusted from the passage predicted by optical tracking. This required adjustment is interpreted as being due to the vector between the theoretical focusing points of the two antennae, i.e. the true radar baseline, differing from the baseline obtained by survey between the antenna foot points. A method to obtain a measurement of the true interferometric baseline using multiple satellite passes is outlined.

  7. Plan of advanced satellite communication experiments using ETS-6

    Science.gov (United States)

    Ikegami, Tetsushi

    1989-01-01

    In 1992, an Engineering Test Satellite 6 is scheduled to be launched by an H-2 rocket. The missions of ETS-6 are to establish basic technologies of inter-satellite communications using S-band, millimeter waves and optical beams and of fixed and mobile satellite communications using multibeam antenna on board the satellite. A plan of the experiments is introduced.

  8. Design of a Push-Broom Multi-Beam Radiometer for Future Ocean Observations

    DEFF Research Database (Denmark)

    Cappellin, C.; Pontoppidan, K.; Nielsen, P. H.

    2015-01-01

    The design of a push-broom multi-beam radiometer for future ocean observations is described. The radiometer provides a sensitivity one order of magnitude higher than a traditional conical scanning radiometer, and has the big advantage of being fully stationary relative to the satellite platform...

  9. Space debris proximity analysis in powered and orbital phases during satellite launch

    Science.gov (United States)

    Bandyopadhyay, Priyankar; Sharma, R. K.; Adimurthy, V.

    2004-01-01

    This paper describes the methodology of the space debris proximity analysis in powered and orbital phase at the time of a satellite launch. The details of the SPADEPRO analysis package, developed for this purpose, are presented. It consists of modules which provide the functions related to ephemeris generation and reconstruction of primary object (launch vehicle or its payload upon insertion), determination of close approaches with resident space objects, computation of the state vector variance of the primary and the secondary objects to represent the knowledge uncertainty, and computation of the collision risk given the variance. This has been successfully applied during the recent launches of the Indian Space Research Organization.

  10. ACTS Multibeam Antenna On-Orbit Performance

    Science.gov (United States)

    Acosta, R.; Wright, D.; Mitchell, Kenneth

    1996-01-01

    The Advanced Communications Technology Satellite (ACTS) launched in September 1993 introduces several new technologies including a multibeam antenna (MBA) operating at Ka-band. The MBA with fixed and rapidly reconfigurable spot beams serves users equipped with small aperture terminals within the coverage area. The antenna produces spot beams with approximately 0.3 degrees beamwidth and gains of approximately 50 dBi. A number of MBA performance evaluations have been performed since the ACTS launch. These evaluations were designed to assess MBA performance (e.g., beam pointing stability, beam shape, gain, etc.) in the space environment. The on-orbit measurements found systematic environmental perturbation to the MBA beam pointing. These perturbations were found to be imposed by satellite attitude control system, antenna and spacecraft mechanical alignments, on-orbit thermal effects, etc. As a result, the footprint coverage of the MBA may not exactly cover the intended service area at all times. This report describes the space environment effects on the ACTS MBA performance as a function of time of the day and time of the year and compensation approaches for these effects.

  11. An application of the multibeam sounder for seabed backscattering analysis

    Digital Repository Service at National Institute of Oceanography (India)

    Chakraborty, B.; Raju, Y.S.N.

    A theoretical analysis of vertical farfield pattern for a multibeam sounder is performed. The farfield pattern for different steered angles establish the usefulness of present multibeam arrays. An interaction effect of different steered multibeam...

  12. Subpixel Accuracy Analysis of Phase Correlation Shift Measurement Methods Applied to Satellite Imagery

    Directory of Open Access Journals (Sweden)

    S.M. Badwai

    2013-01-01

    Full Text Available the key point of super resolution process is the accurate measuring of sub-pixel shift. Any tiny error in measuring such shift leads to an incorrect image focusing. In this paper, methodology of measuring sub-pixel shift using Phase correlation (PC are evaluated using different window functions, then modified version of (PC method using high pass filter (HPF is introduced . Comprehensive analysis and assessment of (PC methods shows that different natural features yield different shift measurements. It is concluded that there is no universal window function for measuring shift; it mainly depends on the features in the satellite images. Even the question of which window is optimal of particular feature is generally remains open. This paper presents the design of a method for obtaining high accuracy sub pixel shift phase correlation using (HPF.The proposed method makes the change in the different locations that lack of edges easy.

  13. Galactic Halo Stars in Phase Space A Hint of Satellite Accretion?

    CERN Document Server

    Brook, C B; Gibson, B K; Flynn, C; Brook, Chris B.; Kawata, Daisuke; Gibson, Brad K.; Flynn, Chris

    2003-01-01

    The present day chemical and dynamical properties of the Milky Way bear the imprint of the Galaxy's formation and evolutionary history. One of the most enduring and critical debates surrounding Galactic evolution is that regarding the competition between ``satellite accretion'' and ``monolithic collapse''; the apparent strong correlation between orbital eccentricity and metallicity of halo stars was originally used as supporting evidence for the latter. While modern-day unbiased samples no longer support the claims for a significant correlation, recent evidence has been presented by Chiba & Beers (2000,AJ,119,2843) for the existence of a minor population of high-eccentricity metal-deficient halo stars. It has been suggested that these stars represent the signature of a rapid (if minor) collapse phase in the Galaxy's history. Employing velocity- and integrals of motion-phase space projections of these stars, coupled with a series of N-body/Smoothed Particle Hydrodynamic (SPH) chemodynamical simulations, we...

  14. Modeling and Simulation of Phased Array Antennas to Support Next-Generation Satellite Design

    Science.gov (United States)

    Tchorowski, Nicole; Murawski, Robert; Manning, Robert; Fuentes, Michael

    2016-01-01

    Developing enhanced simulation capabilities has become a significant priority for the Space Communications and Navigation (SCaN) project at NASA as new space communications technologies are proposed to replace aging NASA communications assets, such as the Tracking and Data Relay Satellite System (TDRSS). When developing the architecture for these new space communications assets, it is important to develop updated modeling and simulation methodologies, such that competing architectures can be weighed against one another and the optimal path forward can be determined. There have been many simulation tools developed here at NASA for the simulation of single RF link budgets, or for the modeling and simulation of an entire network of spacecraft and their supporting SCaN network elements. However, the modeling capabilities are never fully complete and as new technologies are proposed, gaps are identified. One such gap is the ability to rapidly develop high fidelity simulation models of electronically steerable phased array systems. As future relay satellite architectures are proposed that include optical communications links, electronically steerable antennas will become more desirable due to the reduction in platform vibration introduced by mechanically steerable devices. In this research, we investigate how modeling of these antennas can be introduced into out overall simulation and modeling structure. The ultimate goal of this research is two-fold. First, to enable NASA engineers to model various proposed simulation architectures and determine which proposed architecture meets the given architectural requirements. Second, given a set of communications link requirements for a proposed satellite architecture, determine the optimal configuration for a phased array antenna. There is a variety of tools available that can be used to model phased array antennas. To meet our stated goals, the first objective of this research is to compare the subset of tools available to us

  15. Multi-beam linear accelerator EVT

    Energy Technology Data Exchange (ETDEWEB)

    Teryaev, Vladimir E., E-mail: vladimir_teryaev@mail.ru [Omega-P, Inc., New Haven, CT 06510 (United States); Kazakov, Sergey Yu. [Fermilab, Batavia, IL 60510 (United States); Hirshfield, Jay L. [Omega-P, Inc., New Haven, CT 06510 (United States); Yale University, New Haven, CT 06511 (United States)

    2016-09-01

    A novel electron multi-beam accelerator is presented. The accelerator, short-named EVT (Electron Voltage Transformer) belongs to the class of two-beam accelerators. It combines an RF generator and essentially an accelerator within the same vacuum envelope. Drive beam-lets and an accelerated beam are modulated in RF modulators and then bunches pass into an accelerating structure, comprising uncoupled with each other and inductive tuned cavities, where the energy transfer from the drive beams to the accelerated beam occurs. A phasing of bunches is solved by choice correspond distances between gaps of the adjacent cavities. Preliminary results of numerical simulations and the initial specification of EVT operating in S-band, with a 60 kV gun and generating a 2.7 A, 1.1 MV beam at its output is presented. A relatively high efficiency of 67% and high design average power suggest that EVT can find its use in industrial applications.

  16. Effects of the Number of Active Receiver Channels on the Sensitivity of a Reflector Antenna System with a Multi-Beam Wideband Phased Array Feed

    CERN Document Server

    Iupikov, O

    2016-01-01

    A method for accurate modeling of a reflector antenna system with a wideband phased array feed is presented and used to study the effects of the number of active antenna elements and associated receiving channels on the receiving sensitivity of the antenna system. Numerical results are shown for a practical design named APERTIF that is currently under developed at The Netherlands Institute for Radio Astronomy (ASTRON).

  17. Phase 2 Final Report. IAEA Safeguards: Implementation blueprint of commercial satellite imagery

    Energy Technology Data Exchange (ETDEWEB)

    Andersson, Christer [SSC Satellitbild AB, Solna (Sweden)

    2000-01-01

    This document - IAEA Safeguards: Implementation Blueprint of Commercial Satellite Imagery - constitutes the second report from SSC Satellitbild giving a structured view and solid guidelines on how to proceed with a conceivable implementation of satellite imagery to support Safeguards activities of the Agency. This Phase 2 report presents a large number of concrete recommendations regarding suggested management issues, work organisation, imagery purchasing and team building. The study has also resulted in several lists of actions and preliminary project plans with GANT schedules concerning training, hardware and software, as well as for the initial pilot studies. In both the Phase 1 and Phase 2 studies it is confirmed that the proposed concept of a relatively small Imagery Unit using high-resolution data will be a sound and feasible undertaking. Such a unit capable of performing advanced image processing as a tool for various safeguard tasks will give the Agency an effective instrument for reference, monitoring, verification, and detection of declared and undeclared activities. The total cost for implementing commercial satellite imagery at the Department for Safeguards, as simulated in these studies, is approximately MUSD 1,5 per year. This cost is founded on an activity scenario with a staff of 4 experts working in an IAEA Imagery Unit with a workload of three dossiers or issues per week. The imagery unit is built around an advanced PC image processing system capable of handling several hundreds of pre-processed images per year. Alternatively a Reduced Scenario with a staff of 3 would need a budget of approximately MUSD 0,9 per year, whereas an Enhanced Imagery Unit including 5 experts and a considerably enlarged capacity would cost MUSD 1,7 per year. The Imagery Unit should be organised so it clearly reflects the objectives and role as set by the Member States and the management of the Agency. We recommend the Imagery Unit to be organised into four main work

  18. Earth's gravity field modelling based on satellite accelerations derived from onboard GPS phase measurements

    Science.gov (United States)

    Guo, X.; Ditmar, P.; Zhao, Q.; Klees, R.; Farahani, H. H.

    2017-09-01

    GPS data collected by satellite gravity missions can be used for extracting the long-wavelength part of the Earth's gravity field. We propose a new data processing method which makes use of the `average acceleration' approach to gravity field modelling. In this method, satellite accelerations are directly derived from GPS carrier phase measurements with an epoch-differenced scheme. As a result, no ambiguity solutions are needed and the systematic errors that do not change much from epoch to epoch are largely eliminated. The GPS data collected by the Gravity Field and Steady-State Ocean Circulation Explorer (GOCE) satellite mission are used to demonstrate the added value of the proposed method. An analysis of the residual accelerations shows that accelerations derived in this way are more precise, with noise being reduced by about 20 and 5% at the cross-track component and the other two components, respectively, as compared to those based on kinematic orbits. The accelerations obtained in this way allow the recovery of the gravity field to a slightly higher maximum degree compared to the solution based on kinematic orbits. Furthermore, the gravity field solution has an overall better performance. Errors in spherical harmonic coefficients are smaller, especially at low degrees. The cumulative geoid height error is reduced by about 15 and 5% up to degree 50 and 150, respectively. An analysis in the spatial domain shows that large errors along the geomagnetic equator, which are caused by a high electron density coupled with large short-term variations, are substantially reduced. Finally, the new method allows for a better observation of mass transport signals. In particular, sufficiently realistic signatures of regional mass anomalies in North America and south-west Africa are obtained.

  19. Earth's gravity field modelling based on satellite accelerations derived from onboard GPS phase measurements

    Science.gov (United States)

    Guo, X.; Ditmar, P.; Zhao, Q.; Klees, R.; Farahani, H. H.

    2017-02-01

    GPS data collected by satellite gravity missions can be used for extracting the long-wavelength part of the Earth's gravity field. We propose a new data processing method which makes use of the `average acceleration' approach to gravity field modelling. In this method, satellite accelerations are directly derived from GPS carrier phase measurements with an epoch-differenced scheme. As a result, no ambiguity solutions are needed and the systematic errors that do not change much from epoch to epoch are largely eliminated. The GPS data collected by the Gravity Field and Steady-State Ocean Circulation Explorer (GOCE) satellite mission are used to demonstrate the added value of the proposed method. An analysis of the residual accelerations shows that accelerations derived in this way are more precise, with noise being reduced by about 20 and 5% at the cross-track component and the other two components, respectively, as compared to those based on kinematic orbits. The accelerations obtained in this way allow the recovery of the gravity field to a slightly higher maximum degree compared to the solution based on kinematic orbits. Furthermore, the gravity field solution has an overall better performance. Errors in spherical harmonic coefficients are smaller, especially at low degrees. The cumulative geoid height error is reduced by about 15 and 5% up to degree 50 and 150, respectively. An analysis in the spatial domain shows that large errors along the geomagnetic equator, which are caused by a high electron density coupled with large short-term variations, are substantially reduced. Finally, the new method allows for a better observation of mass transport signals. In particular, sufficiently realistic signatures of regional mass anomalies in North America and south-west Africa are obtained.

  20. Phase behavior and thermodynamic modeling of ices - implications for the geophysics of icy satellites. (Invited)

    Science.gov (United States)

    Choukroun, M.

    2010-12-01

    Ground-based observations and space missions to the outer Solar System (Voyager, Galileo, Cassini-Huygens) have evidenced recent geologic activity on many satellites of the giant planets. The diversity in surface expression of these icy moons’ activity is striking: from a scarred and young surface on Europa,1 with hydrated salts that may originate from a liquid layer buried at depth,2 to the South Polar plumes of Enceladus,3 where water ice particles are expelled along with a myriad of more complex molecules,4 to Titan, largest satellite of Saturn, with a dense atmosphere and a hydrocarbon cycle similar to the hydrological cycle on Earth.5 Large icy moons, i.e. with a radius greater than 500 km, share two particularities: a high content in water (on the order of a 30-70% bulk composition), and an interior segregated between a water-dominated mantle and a silicate-dominated core. The many forms water may have beneath the surface (ice polymorphs, liquid, hydrated compounds) bear a crucial role in the detected or alleged activity, and in the potential for astrobiological relevance. Indeed, any endogenic activity can only be approached through geophysical modelling of the internal structure and the thermal evolution. Current internal structure models for the icy moonse.g.,6 rely mainly on the contribution of each internal layer to the moment of inertia, generating non-unique solutions due to the large variability in density of H2O-bearing phases. Thermal evolution models,e.g.,7 can help constrain further the internal structure and geophysical activity, by starting with a given initial composition and state and investigating the thickening of icy layers through time. However, such models require both observational datasets and a precise description, as a function of pressure, temperature, and composition, of the thermophysical properties of the individual layers. Over the past century, experimental studies have provided a comprehensive view of the phase diagram of

  1. Carrier-phase Two-Way Satellite Frequency Transfer over a Very Long Baseline

    CERN Document Server

    Fujieda, M; Gotoh, T; Becker, J; Aida, M; Bauch, A

    2014-01-01

    In this paper we report that carrier-phase two-way satellite time and frequency transfer (TWSTFT) was successfully demonstrated over a very long baseline of 9,000 km, established between the National Institute of Information and Communications Technology (NICT) and the Physikalisch-Technische Bundesanstalt (PTB). We verified that the carrier-phase TWSTFT (TWCP) result agreed with those obtained by conventional TWSTFT and GPS carrier-phase (GPSCP) techniques. Moreover, a much improved short-term instability for frequency transfer of $2\\times10^{-13}$ at 1 s was achieved, which is at the same level as previously confirmed over a shorter baseline within Japan. The precision achieved was so high that the effects of ionospheric delay became significant which are ignored in conventional TWSTFT even over a long link. We compensated for these effects using ionospheric delays computed from regional vertical total electron content maps. The agreement between the TWCP and GPSCP results was improved because of this compe...

  2. High-Sensitivity Phased Arrays for Radio Astronomy and Satellite Communications

    Science.gov (United States)

    Diao, Junming

    Radio astronomy is used to study stars, galaxies, black holes and gas clouds radiation at radio frequencies. Detecting extremely weak signals from deep space radio sources requires high sensitive feed system associated with large dish antennas. The key figure of merit is survey speed, or the time required to map a region of the sky to a given source flux density. Survey speed is proportional to the frequency bandwidth, the field of view or observable region of the sky, and the squared sensitivity, where sensitivity is related to reflector aperture efficiency and system noise temperature. Compared to the traditional single feed, phased array feeds with significantly expanded field of view are considered as the next generation feed for radio telescope. This dissertation outlines the design, analysis and measurement of high sensitivity L-band and mm-wave phased array feeds for the 100-meter Green Bank Telescope. Theoretical works for radio astronomy includes design guideline for high sensitivity phased array feed, fundamental frequency bandwidth limit, array antenna loss influenced by mutual coupling and beamformer coefficients and possibility of superdirectivity for radio telescopes and other antennas. These study are helpful to understand and guide the design of a phased array feed system. In the absence of dish antennas, sparse phased arrays with aperiodic structure have been developed for satellite communications. A compromise between the peak side lobe level, array element density, directivity and design complexity is studied. We have found that the array peak side lobe level can be reduced by enhancing the array element direction at the main lobe direction, increasing the array element density and enlarging the array size. A Poynting streamline approach develops to understand the properties of a receiving antenna and the mutual coupling effects between array elements. This method has been successfully used to generate effective area shape for many types of

  3. Phase 2 Final Report. IAEA Safeguards: Implementation blueprint of commercial satellite imagery

    Energy Technology Data Exchange (ETDEWEB)

    Andersson, Christer [SSC Satellitbild AB, Solna (Sweden)

    2000-01-01

    This document - IAEA Safeguards: Implementation Blueprint of Commercial Satellite Imagery - constitutes the second report from SSC Satellitbild giving a structured view and solid guidelines on how to proceed with a conceivable implementation of satellite imagery to support Safeguards activities of the Agency. This Phase 2 report presents a large number of concrete recommendations regarding suggested management issues, work organisation, imagery purchasing and team building. The study has also resulted in several lists of actions and preliminary project plans with GANT schedules concerning training, hardware and software, as well as for the initial pilot studies. In both the Phase 1 and Phase 2 studies it is confirmed that the proposed concept of a relatively small Imagery Unit using high-resolution data will be a sound and feasible undertaking. Such a unit capable of performing advanced image processing as a tool for various safeguard tasks will give the Agency an effective instrument for reference, monitoring, verification, and detection of declared and undeclared activities. The total cost for implementing commercial satellite imagery at the Department for Safeguards, as simulated in these studies, is approximately MUSD 1,5 per year. This cost is founded on an activity scenario with a staff of 4 experts working in an IAEA Imagery Unit with a workload of three dossiers or issues per week. The imagery unit is built around an advanced PC image processing system capable of handling several hundreds of pre-processed images per year. Alternatively a Reduced Scenario with a staff of 3 would need a budget of approximately MUSD 0,9 per year, whereas an Enhanced Imagery Unit including 5 experts and a considerably enlarged capacity would cost MUSD 1,7 per year. The Imagery Unit should be organised so it clearly reflects the objectives and role as set by the Member States and the management of the Agency. We recommend the Imagery Unit to be organised into four main work

  4. BeiDou and Galileo, Two Global Satellite Navigation Systems in Final Phase of the Construction, Visibility and Geometry

    Directory of Open Access Journals (Sweden)

    Jacek Januszewski

    2016-09-01

    Full Text Available Spatial segment is one of three segments of each satellite navigation systems (SNS. Nowadays two SNSs, GPS and GLONASS, are fully operational, two next SNSs, BeiDou in China and Galileo in Europe, are in final phase of the construction. In the case of China system this segment will consist of 35 satellites with three types of orbits ? medium (MEO, geostationary (GEO and inclined geosynchronous (IGSO. As GEO and IGSO satellites can be used in China and Asia-Pacific region only, BeiDou MEO constellation with 27 fully operational satellites will be taken into account in this paper. The orbital planes of the Galileo constellation will be divided in “slots” that contains at least one operational satellite. The Galileo reference constellation has 24 nominal orbital positions or operational slots in MEO homogeneously distributed in 3 orbital planes; i.e. 8 slots equally spaced per plane. As the error of user’s position obtained from both systems depends on geometry factor DOP (Dilution Of Precision among other things the knowledge of the number of satellites visible by the user above given masking elevation angle Hmin and the distributions of DOP coefficient values, GDOP in particular, is very important. The lowest and the greatest number of satellites visible in open area by the observer at different latitudes for different Hmin, the percentage of satellites visible above angle H, distributions (in per cent of satellites azimuths and GDOP coefficient values for different Hmin for BeiDou and Galileo systems at different latitudes are presented in the paper.

  5. PHASES: a concept for a satellite-borne ultra-precise spectrophotometer

    CERN Document Server

    del Burgo, Carlos; Peacocke, Tully; 10.1088/1748-0221/5/01/P01006

    2010-01-01

    The Planet Hunting and Asteroseismology Explorer Spectrophotometer, PHASES, is a concept for a space-borne instrument to obtain flux calibrated spectra and measure micro-magnitude photometric variations of nearby stars. The science drivers are the determination of the physical properties of stars and the characterisation of planets orbiting them, to very high precision. PHASES, intended to be housed in a micro-satellite, consists of a 20 cm aperture modified Baker telescope feeding two detectors: the tracking detector, with a field of 1 degree square, and the science detector for performing spectrophotometry. The optical design has been developed with the primary goal of avoiding stray light on the science detector, while providing spectra in the wavelength range 370-960 nm with a resolving power that ranges from ~900 at 370 nm to ~200 at 960 nm. The signal to noise per resolution element obtained for a V=10 magnitude star in a 1 minute integration varies between ~ 35 and 140. An analysis of the light curve c...

  6. Autonomous Satellite Command and Control Through the World Wide Web. Phase 3

    Science.gov (United States)

    Cantwell, Brian; Twiggs, Robert

    1998-01-01

    The Automated Space System Experimental Testbed (ASSET) system is a simple yet comprehensive real-world operations network being developed. Phase 3 of the ASSET Project was January-December 1997 and is the subject of this report. This phase permitted SSDL and its project partners to expand the ASSET system in a variety of ways. These added capabilities included the advancement of ground station capabilities, the adaptation of spacecraft on-board software, and the expansion of capabilities of the ASSET management algorithms. Specific goals of Phase 3 were: (1) Extend Web-based goal-level commanding for both the payload PI and the spacecraft engineer. (2) Support prioritized handling of multiple (PIs) Principle Investigators as well as associated payload experimenters. (3) Expand the number and types of experiments supported by the ASSET system and its associated spacecraft. (4) Implement more advanced resource management, modeling and fault management capabilities that integrate the space and ground segments of the space system hardware. (5) Implement a beacon monitoring test. (6) Implement an experimental blackboard controller for space system management. (7) Further define typical ground station developments required for Internet-based remote control and for full system automation of the PI-to-spacecraft link. Each of those goals are examined. Significant sections of this report were also published as a conference paper. Several publications produced in support of this grant are included as attachments. Titles include: 1) Experimental Initiatives in Space System Operations; 2) The ASSET Client Interface: Balancing High Level Specification with Low Level Control; 3) Specifying Spacecraft Operations At The Product/Service Level; 4) The Design of a Highly Configurable, Reusable Operating System for Testbed Satellites; 5) Automated Health Operations For The Sapphire Spacecraft; 6) Engineering Data Summaries for Space Missions; and 7) Experiments In Automated Health

  7. Detection of supercooled liquid water-topped mixed-phase clouds >from shortwave-infrared satellite observations

    Science.gov (United States)

    NOH, Y. J.; Miller, S. D.; Heidinger, A. K.

    2015-12-01

    Many studies have demonstrated the utility of multispectral information from satellite passive radiometers for detecting and retrieving the properties of cloud globally, which conventionally utilizes shortwave- and thermal-infrared bands. However, the satellite-derived cloud information comes mainly from cloud top or represents a vertically integrated property. This can produce a large bias in determining cloud phase characteristics, in particular for mixed-phase clouds which are often observed to have supercooled liquid water at cloud top but a predominantly ice phase residing below. The current satellite retrieval algorithms may report these clouds simply as supercooled liquid without any further information regarding the presence of a sub-cloud-top ice phase. More accurate characterization of these clouds is very important for climate models and aviation applications. In this study, we present a physical basis and preliminary results for the algorithm development of supercooled liquid-topped mixed-phase cloud detection using satellite radiometer observations. The detection algorithm is based on differential absorption properties between liquid and ice particles in the shortwave-infrared bands. Solar reflectance data in narrow bands at 1.6 μm and 2.25 μm are used to optically probe below clouds for distinction between supercooled liquid-topped clouds with and without an underlying mixed phase component. Varying solar/sensor geometry and cloud optical properties are also considered. The spectral band combination utilized for the algorithm is currently available on Suomi NPP Visible/Infrared Imaging Radiometer Suite (VIIRS), Himawari-8 Advanced Himawari Imager (AHI), and the future GOES-R Advance Baseline Imager (ABI). When tested on simulated cloud fields from WRF model and synthetic ABI data, favorable results were shown with reasonable threat scores (0.6-0.8) and false alarm rates (0.1-0.2). An ARM/NSA case study applied to VIIRS data also indicated promising

  8. PHASES: a concept for a satellite-borne ultra-precise spectrophotometer

    Energy Technology Data Exchange (ETDEWEB)

    Burgo, C del [UNINOVA-CA3, Campus da Caparica, Quinta da Torre, Monte de Caparica 2825-149, Caparica (Portugal); Prieto, C Allende [Mullard Space Science Laboratory, University College London, Holmbury St. Mary, Dorking, Surrey RH5 6NT (United Kingdom); Peacocke, T, E-mail: cburgo@uninova.p [Experimental Physics, National University of Ireland, Maynooth, Co. Kildare (Ireland)

    2010-01-15

    The Planet Hunting and Asteroseismology Explorer Spectrophotometer, PHASES, is a concept for a space-borne instrument to obtain flux calibrated spectra and measure micro-magnitude photometric variations of nearby stars. The science drivers are the determination of the physical properties of stars and the characterisation of planets orbiting them, to very high precision. PHASES, intended to be housed in a micro-satellite, consists of a 20 cm aperture modified Baker telescope feeding two detectors: the tracking detector, with a field of 1 degree square, and the science detector for performing spectrophotometry. The optical design has been developed with the primary goal of avoiding stray light on the science detector, while providing spectra in the wavelength range 370-960 nm with a resolving power that ranges from {approx} 900 at 370 nm to {approx} 200 at 960 nm. The signal to noise per resolution element obtained for a V = 10 magnitude star in a 1 minute integration varies between {approx} 35 and 140. An analysis of the light curve constrains the radii of the planets relative to their parent stars' radii, which are, in turn, tightly constrained by the combination of absolute spectrophotometry and trigonometric parallaxes. The provisional optical design satisfies all the scientific requirements, including a {approx} 1% rms flux calibration strategy based on observations of bright A-type stars and model atmospheres, allowing the determination of stellar angular diameters for nearby solar-like stars to 0.5%. This level of accuracy will be propagated to the stellar radii for the nearest stars, with highly reliable Hipparcos parallaxes, and more significantly, to the planetary radii.

  9. Technological Progress on Multi-Beam Klystrons

    Science.gov (United States)

    Ding, Yaogen

    2006-01-01

    The technological progress on Multi-Beam Klystrons (MBKs) at the Institute of Electronics, Chinese Academy of Sciences (IECAS) is presented in this paper. Topics to be discussed include the development of cathodes with high current densities and low evaporation rates; multi-beam electron guns with reduced chances for breakdown; multi-beam electron optics systems with high beam transmission; RF systems with wide bandwidth and high efficiency; the oscillation and broad spectrum noise caused by non-operational modes and reflecting electrons; and computer simulations of the multi-beam electron optics system and beam-wave interaction. In addition, the research progress of several types of MBKs developed in IECAS is reported. These MBKs range in frequency from L- to X-band with corresponding peak powers ranging from several tens to several hundreds of kilowatts, average powers from several kilowatts to tens of kilowatts, and bandwidths from 3% to 12%.

  10. Icy satellites of Saturn: disk-integrated observations of the brightness opposition surge at low phase angles

    Science.gov (United States)

    Kulyk, I.; Jockers, K.

    2007-08-01

    The surfaces of most atmosphereless bodies exhibit two interesting optical phenomena at small phase angles, namely a strong brightness increase and negative values of the degree of linear polarization. Of particular interest is the appearance a nonlinear growth of the surface brightness and a second narrow minimum of polarization at phase angles less than 1-3°. These features of brightness and polarization in the narrow phase angle range near opposition are called the photometric and polarimetric opposition effects. These phenomena have attracted increased attention from the perspective of theories of light scattering in random media and their application to the determination of properties of the upper optically active regolith layers on the atmosphereless bodies. However, up to now photometric and especially polarimetric observations conducted at small phase angles are rare. In order to enlarge the amount of available observational data we have conducted photopolarimetric observations of the major icy Saturnian satellites. The observations were performed at the 2m-telescope of the Bulgarian National Observatory with the Two-Channel Focal Reducer of the Bulgarian Academy of Sciences built at the Max-Planck-Institute for Solar System Science. This instrument incorporates a two-channel imaging polarimeter which can be used in coronagraph setup. The light of Saturn and its rings is almost fully absorbed by a black glass and its diffraction pattern is eliminated by a Lyot stop. The photopolarimeter records intensity and degree of polarization of the satellites in two colors simultaneously. In this study, we present the first results of the disk-integrated photometry of Enceladus, Tethys, Dione, and Rhea in the red (center wavelength 694 nm, FWHM 79 nm) and near-infrared (center wavelength 888.5 nm, FWHM 29 nm, methane absorption band) spectral bands at phase angles between 5.6° and 0.01°. The resulting magnitudes can be represented as a sum of two terms, one

  11. Impact of turbulent phase noise on frequency transfer with asymmetric two-way ground-satellite coherent optical links

    Science.gov (United States)

    Robert, Clélia; Conan, Jean-Marc; Wolf, Peter

    2016-06-01

    Bidirectional ground-satellite laser links suffer from turbulence-induced scintillation and phase distortion. We study how turbulence impacts on coherent detection capacity and on the associated phase noise that restricts clock transfer precision. We evaluate the capacity to obtain a two-way cancellation of atmospheric effects despite the asymmetry between up and down link that limits the link reciprocity. For ground-satellite links, the asymmetry is induced by point-ahead angle and possibly the use, for the ground terminal, of different transceiver diameters, in reception and emission. The quantitative analysis is obtained thanks to refined end- to-end simulations under realistic turbulence and wind conditions as well as satellite cinematic. These temporally resolved simulations allow characterizing the coherent detection in terms of time series of heterodyne efficiency for different system parameters. We show that Tip/Tilt correction on ground is mandatory at reception for the down link and as a pre-compensation of the up link. Good correlation between up and down phase noise is obtained even with asymmetric apertures of the ground transceiver and in spite of pointing ahead angle. The reduction to less than 1 rad2 of the two-way differential phase noise is very promising for clock comparisons.

  12. X-ray observations of the impulsive phase of solar flares with the Yohkoh satellite

    Science.gov (United States)

    Phillips, Andrew

    This thesis starts with an overview of the physics of the solar corona, concentrating on X-ray emission and the plasma dynamics associated with the impulsive or rise phase of solar flares. The Yohkoh satellite is described, with a section on each major instrument on board. Analysis techniques used in the thesis are then introduced, with a section of soft X-ray spectroscopy and on the application of the Maximum Entropy Method image reconstruction technique to data from the Hard X-ray Telescope on Yohkoh. The instrumental effect known as fixed pattern noise is described, leading to a numerical model of the BCS digitisation process, which is used both to understand the limits of the detector, and to correct the data in a limited way. Alternative methods for the avoidance of fixed pattern noise are evaluated. The analysis of a solar flare with unusually large soft X-ray blue shifts is then performed. Physical parameters of the plasma during the initial stages of the flare are derived, which are used in an energy balance calculation. Agreement is found between the energy in nonthermal electrons and that contained in the coronal plasma, supporting the nonthermal beam driven chromospheric evaporation theory of impulsive flares. The location of superhot plasma in two impulsive flares and one hot thermal flare is then investigated. Superhot plasma is found to be located close to the chromosphere, and related to the nonthermal burst in the two impulsive flares. Superhot plasma in the hot thermal flare is distributed uniformly throughout the loop. The differences are explained as being due to the different energy transport processes active in each type of flare.

  13. ACTS on-orbit multibeam antenna pattern measurements

    Science.gov (United States)

    Acosta, R.; Wright, D.; Regier, F.

    1995-01-01

    The Advanced Communication Technology (ACTS) is a key to NASA's goal of developing high-risk, advanced communications technology using multiple frequency bands to support the nation's future communication needs. Using the multiple, dynamic hopping spot beams and advanced on board switching and processing systems, ACTS will open a new era in communications satellite technology. One of the key technologies to be validated as part of the ACTS program is the multibeam antenna (MBA) with rapidly reconfigurable hopping and fixed spot beams to serve users equipped with small-aperture terminals within the coverage areas. The MBA test program is designed to evaluate the on-orbit ACTS antenna performance. The main parameters measured are beam shape, beam center location and gain.

  14. Phase Residual Estimations for PCVs of Spaceborne GPS Receiver Antenna and Their Impacts on Precise Orbit Determination of GRACE Satellites

    Institute of Scientific and Technical Information of China (English)

    TU Jia; GU Defeng; WU Yi; YI Dongyun

    2012-01-01

    In-flight phase center systematic errors of global positioning system (GPS) receiver antenna are the main restriction for improving the precision of precise orbit determination using dual-frequency GPS.Residual approach is one of the valid methods for in-flight calibration of GPS receiver antenna phase center variations (PCVs) from ground calibration.In this paper,followed by the correction model of spaceborne GPS receiver antenna phase center,ionosphere-free PCVs can be directly estimated by ionosphere-free carrier phase post-fit residuals of reduced dynamic orbit determination.By the data processing of gravity recovery and climate experiment (GRACE) satellites,the following conclusions are drawn.Firstly,the distributions of ionosphere-free carrier phase post-fit residuals from different periods have the similar systematic characteristics.Secondly,simulations show that the influence of phase residual estimations for ionosphere-free PCVs on orbit determination can reach the centimeter level.Finally,it is shown by in-flight data processing that phase residual estimations of current period could not only be used for the calibration for GPS receiver antenna phase center of foretime and current period,but also be used for the forecast of ionosphere-free PCVs in future period,and the accuracy of orbit determination can be well improved.

  15. Measuring Phased-Array Antenna Beampatterns with High Dynamic Range for the Murchison Widefield Array using 137 MHz ORBCOMM Satellites

    CERN Document Server

    Neben, A R; Hewitt, J N; Bernardi, G; Bowman, J D; Briggs, F; Cappallo, R J; Deshpande, A A; Goeke, R; Greenhill, L J; Hazelton, B J; Johnston-Hollitt, M; Kaplan, D L; Lonsdale, C J; McWhirter, S R; Mitchell, D A; Morales, M F; Morgan, E; Oberoi, D; Ord, S M; Prabu, T; Shankar, N Udaya; Srivani, K S; Subrahmanyan, R; Tingay, S J; Wayth, R B; Webster, R L; Williams, A; Williams, C L

    2015-01-01

    Detection of the fluctuations in 21 cm line emission from neutral hydrogen during the Epoch of Reionization in thousand hour integrations poses stringent requirements on calibration and image quality, both of which necessitate accurate primary beam models. The Murchison Widefield Array (MWA) uses phased array antenna elements which maximize collecting area at the cost of complexity. To quantify their performance, we have developed a novel beam measurement system using the 137 MHz ORBCOMM satellite constellation and a reference dipole antenna. Using power ratio measurements, we measure the {\\it in situ} beampattern of the MWA antenna tile relative to that of the reference antenna, canceling the variation of satellite flux or polarization with time. We employ angular averaging to mitigate multipath effects (ground scattering), and assess environmental systematics with a null experiment in which the MWA tile is replaced with a second reference dipole. We achieve beam measurements over 30 dB dynamic range in beam...

  16. Odyssey, an optimized personal communications satellite system

    Science.gov (United States)

    Rusch, Roger J.

    Personal communications places severe demands on service providers and transmission facilities. Customers are not satisfied with the current levels of service and want improvements. Among the characteristics that users seek are: lower service rates, hand held convenience, acceptable time delays, ubiquitous service, high availability, reliability, and high quality. The space industry is developing commercial space systems for providing mobile communications to personal telephones. Provision of land mobile satellite service is fundamentally different from the fixed satellite service provided by geostationary satellites. In fixed service, the earth based antennas can depend on a clear path from user to satellite. Mobile users in a terrestrial environment commonly encounter blockage due to vegetation, terrain or buildings. Consequently, high elevation angles are of premium value. TRW studied the issues and concluded that a Medium Earth Orbit constellation is the best solution for Personal Communications Satellite Service. TRW has developed Odyssey, which uses twelve satellites in medium altitude orbit to provide personal communications satellite service. The Odyssey communications system projects a multibeam antenna pattern to the Earth. The attitude control system orients the satellites to ensure constant coverage of land mass and coastal areas. Pointing can be reprogrammed by ground control to ensure optimized coverage of the desired service areas. The payload architecture features non-processing, "bent pipe" transponders and matrix amplifiers to ensure dynamic power delivery to high demand areas. Circuit capacity is 3000 circuits per satellite. Each satellite weighs 1917 kg (4226 pounds) at launch and the solar arrays provide 3126 Watts of power. Satellites are launched in pairs on Ariane, Atlas, or other vehicles. Each satellite is placed in a circular orbit at an altitude of 10,354 km. There are three orbit planes inclined at 55° to the equatorial plane

  17. Advanced Communications Technology Satellite (ACTS). Phase 1: Industrial/academic experimenters

    Science.gov (United States)

    Maisel, James E.; Nowlin, Robert W.

    1992-01-01

    This report presents the work done at Arizona State University under the ACTS Experimenters Program. The main thrust of the Program was to develop experiments to test, evaluate, and prove the commercial worthiness of the ACTS satellite which is scheduled for launch in 1993. To accomplish this goal, meetings were held with various governmental, industrial, and academic units to discuss the ACTS satellite and its technology and possible experiments that would generate industrial interest and support for ASU's efforts. Several local industries generated several experiments of their own. The investigators submitted several experiments of educational, medical, commercial, and technical value and interest. The disposition of these experimental proposals is discussed in this report.

  18. Data Fusion Technique for Multibeam Echosoundings

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    On the basis of an analysis of the error sources in multibeam echosounding system,a data processing method for compensating systematic errors in multibeam survey is proposed.In order to improve the accuracy of overall swath,a data fusion technique using single beam survey data as control information for single beam and multibeam echosounding is then presented.Some questions involved in solving the adjustment problem,such as its feasibility and the numerical stability,are discussed in detail,and a two-step adjustment method is suggested.Finally,a practical survey data set is used as a case study to prove the efficiency and reliability of the proposed methods.

  19. Radiated EMC& EMI Management During Design Qualification and Test Phases on LEO Satellites Constellation

    Science.gov (United States)

    Blondeaux, H.; Terral, M.; Gutierrez-Galvan, R.; Baud, C.

    2016-05-01

    The aim of the proposed paper is to present the global radiated EMC/EMI approach applied by Thales Alenia Space in the frame of a telecommunication Low Earth Orbit (LEO) satellites constellation program. The paper will present this approach in term of analyses, of specific characterisation and of sub-system and satellite tests since first design reviews up-to satellite qualification tests on Prototype Flight Model (PFM) and to production tests on reduced FMs. The global aim is : 1 - to reduce risk and cost (units EMC delta qualification, EMC tests at satellite level for the 81 Space Vehicles (SV) through appropriated EMC analyses (in term of methodologies and contours) provided in the frame of design reviews.2 - to early anticipate potential critical case to reduce the impact in term of engineering/qualification/test extra cost and of schedule.3 - to secure/assure the payload and SV design/layout.4 - to define and optimize the EMC/EMI test campaigns to be performed on Prototype Flight Model (PFM) for complete qualification and on some FMs for industrial qualification/validation.The last part of the paper is dedicated to system Bite Error Rate (BER) functional test performed on PFM SV to demonstrate the final compatibility between the three on-board payloads and to the Internal EMC tests performed on PFM and some FMs to demonstrate the SV panel RF shielding efficiency before and after environmental tests and the Thales Alenia Space (TAS) and Orbital AKT (OATK) workmanships reproducibility.

  20. Broadband conformal phased array with optical beam forming for airborne satellite communication

    NARCIS (Netherlands)

    Schippers, H.; Verpoorte, J.; Jorna, P.; Hulzinga, A.; Meijerink, A.; Roeloffzen, C.G.H.; Zhuang, L.; Marpaung, D.A.I.; Etten, van W.; Heideman, R.G.; Leinse, A.; Borreman, A.; Hoekman, M.; Wintels, M.

    2008-01-01

    For enhanced communication on board an aircraft, novel antenna systems with broadband satellite based capabilities are required. The technology will enhance airline operations by providing in-flight connectivity for flight crew information and will bring live TV and high speed Internet connectivity

  1. Coherence and phase structure of compressional ULF waves at low-Earth-orbit observed by the Swarm satellites

    Science.gov (United States)

    Heilig, Balázs; Sutcliffe, Peter R.

    2016-04-01

    Different types of ultra low frequency (ULF waves), such as dayside compressional Pc3-Pc4 waves, Pc2 and Pc1 waves, Pc3-Pc4 field line resonances, night side and day side Pi2s, etc. have been successfully identified in the topside ionosphere. ULF observations in this region can help us to understand the wave structure in the magnetosphere, wave propagation, and also the effects of the ionosphere (transmission, reflection, mode conversion). Because of the fast orbiting of the LEO satellites Fourier analysis is not applicable, special techniques (wavelet analysis, maximum entropy method) are needed to resolve ULF signals, as well as to discriminate between spatial and wave structures. In this paper we present results of a study of Pc3 compressional waves observed at low-Earth-orbit (LEO) by the Swarm satellites. The particular emphasis has been to investigate the distribution of wave coherence and phase difference as functions of magnetic latitude and local time. This is the first time that a study of this nature has been carried out using magnetic field data from multiple LEO satellites. We believe that our study provides the first observational evidence to support the prediction by the inductive thin ionosphere model that incident Alfvén mode waves are partially converted into compressional mode waves by the ionosphere.

  2. Comparison of the peak resolution and the stationary phase retention between the satellite and the planetary motions using the coil satellite centrifuge with counter-current chromatographic separation of 4-methylumbelliferyl sugar derivatives.

    Science.gov (United States)

    Shinomiya, Kazufusa; Zaima, Kazumasa; Harada, Yukina; Yasue, Miho; Harikai, Naoki; Tokura, Koji; Ito, Yoichiro

    2017-01-20

    Coil satellite centrifuge (CSC) produces the complex satellite motion consisting of the triplicate rotation of the coiled column around three axes including the sun axis (the angular velocity, ω1), the planet axis (ω2) and the satellite axis (the central axis of the column) (ω3) according to the following formula: ω1=ω2+ω3. Improved peak resolution in the separation of 4-methylumbelliferyl sugar derivatives was achieved using the conventional multilayer coiled columns with ethyl acetate/1-butanol/water (3: 2: 5, v/v) for the lower mobile phase at the combination of the rotation speeds (ω1, ω2, ω3)=(300, 150, 150rpm), and (1:4:5, v/v) for the upper mobile phase at (300:100:200rpm). The effect of the satellite motion on the peak resolution and the stationary phase retention was evaluated by each CSC separation with the different rotation speeds of ω2 and ω3 under the constant revolution speed at ω1=300rpm. With the lower mobile phase, almost constant peak resolution and stationary phase retention were yielded regardless of the change of ω2 and ω3, while with the upper mobile phase these two values were sensitively varied according to the different combination of ω2 and ω3. For example, when ω2=147 or 200rpm is used, no stationary phase was retained in the coiled column while ω2=150rpm could retain enough volume of stationary phase for separation. On the other hand, the combined rotation speeds at (ω1, ω2, ω3)=(300, 300, 0rpm) or (300, 0, 300rpm) produced insufficient peak resolution regardless of the choice of the mobile phase apparently due to the lack of rotation speed except at (300, 0, 300rpm) with the upper mobile phase. At lower rotation speed of ω1=300rpm, better peak resolution and stationary phase retention were obtained by the satellite motion (ω3) than by the planetary motion (ω2), or ω3>ω2. The effect of the hydrophobicity of the two-phase solvent systems on the stationary phase retention was further examined using the n

  3. An interhemispheric comparison of GPS phase scintillation with auroral emission observed at the South Pole and from the DMSP satellite

    Directory of Open Access Journals (Sweden)

    Paul Prikryl

    2013-06-01

    Full Text Available The global positioning system (GPS phase scintillation caused by high-latitude ionospheric irregularities during an intense high-speed stream (HSS of the solar wind from April 29 to May 5, 2011, was observed using arrays of GPS ionospheric scintillation and total electron content monitors in the Arctic and Antarctica. The one-minute phase-scintillation index derived from the data sampled at 50 Hz was complemented by a proxy index (delta phase rate obtained from 1-Hz GPS data. The scintillation occurrence coincided with the aurora borealis and aurora australis observed by an all-sky imager at the South Pole, and by special sensor ultraviolet scanning imagers on board satellites of the Defense Meteorological Satellites Program. The South Pole (SP station is approximately conjugate with two Canadian High Arctic Ionospheric Network stations on Baffin Island, Canada, which provided the opportunity to study magnetic conjugacy of scintillation with support of riometers and magnetometers. The GPS ionospheric pierce points were mapped at their actual or conjugate locations, along with the auroral emission over the South Pole, assuming an altitude of 120 km. As the aurora brightened and/or drifted across the field of view of the all-sky imager, sequences of scintillation events were observed that indicated conjugate auroras as a locator of simultaneous or delayed bipolar scintillation events. In spite of the greater scintillation intensity in the auroral oval, where phase scintillation sometimes exceeded 1 radian during the auroral break-up and substorms, the percentage occurrence of moderate scintillation was highest in the cusp. Interhemispheric comparisons of bipolar scintillation maps show that the scintillation occurrence is significantly higher in the southern cusp and polar cap.

  4. GNSS Carrier Phase Integer Ambiguity Resolution with Camera and Satellite images

    Science.gov (United States)

    Henkel, Patrick

    2015-04-01

    Ambiguity Resolution is the key to high precision position and attitude determination with GNSS. However, ambiguity resolution of kinematic receivers becomes challenging in environments with substantial multipath, limited satellite availability and erroneous cycle slip corrections. There is a need for other sensors, e.g. inertial sensors that allow an independent prediction of the position. The change of the predicted position over time can then be used for cycle slip detection and correction. In this paper, we provide a method to improve the initial ambiguity resolution for RTK and PPP with vision-based position information. Camera images are correlated with geo-referenced aerial/ satellite images to obtain an independent absolute position information. This absolute position information is then coupled with the GNSS and INS measurements in an extended Kalman filter to estimate the position, velocity, acceleration, attitude, angular rates, code multipath and biases of the accelerometers and gyroscopes. The camera and satellite images are matched based on some characteristic image points (e.g. corners of street markers). We extract these characteristic image points from the camera images by performing the following steps: An inverse mapping (homogenous projection) is applied to transform the camera images from the driver's perspective to bird view. Subsequently, we detect the street markers by performing (a) a color transformation and reduction with adaptive brightness correction to focus on relevant features, (b) a subsequent morphological operation to enhance the structure recognition, (c) an edge and corner detection to extract feature points, and (d) a point matching of the corner points with a template to recognize the street markers. We verified the proposed method with two low-cost u-blox LEA 6T GPS receivers, the MPU9150 from Invensense, the ASCOS RTK corrections and a PointGrey camera. The results show very precise and seamless position and attitude

  5. Note: Inter-satellite laser range-rate measurement by using digital phase locked loop.

    Science.gov (United States)

    Liang, Yu-Rong; Duan, Hui-Zong; Xiao, Xin-Long; Wei, Bing-Bing; Yeh, Hsien-Chi

    2015-01-01

    This note presents an improved high-resolution frequency measurement system dedicated for the inter-satellite range-rate monitoring that could be used in the future's gravity recovery mission. We set up a simplified common signal test instead of the three frequencies test. The experimental results show that the dominant noises are the sampling time jitter and the thermal drift of electronic components, which can be reduced by using the pilot-tone correction and passive thermal control. The improved noise level is about 10(-8) Hz/Hz(1/2)@0.01Hz, limited by the signal-to-noise ratio of the sampling circuit.

  6. Multibeam monopulse radar for airborne sense and avoid system

    Science.gov (United States)

    Gorwara, Ashok; Molchanov, Pavlo

    2016-10-01

    The multibeam monopulse radar for Airborne Based Sense and Avoid (ABSAA) system concept is the next step in the development of passive monopulse direction finder proposed by Stephen E. Lipsky in the 80s. In the proposed system the multibeam monopulse radar with an array of directional antennas is positioned on a small aircaraft or Unmanned Aircraft System (UAS). Radar signals are simultaneously transmitted and received by multiple angle shifted directional antennas with overlapping antenna patterns and the entire sky, 360° for both horizontal and vertical coverage. Digitizing of amplitude and phase of signals in separate directional antennas relative to reference signals provides high-accuracy high-resolution range and azimuth measurement and allows to record real time amplitude and phase of reflected from non-cooperative aircraft signals. High resolution range and azimuth measurement provides minimal tracking errors in both position and velocity of non-cooperative aircraft and determined by sampling frequency of the digitizer. High speed sampling with high-accuracy processor clock provides high resolution phase/time domain measurement even for directional antennas with wide Field of View (FOV). Fourier transform (frequency domain processing) of received radar signals provides signatures and dramatically increases probability of detection for non-cooperative aircraft. Steering of transmitting power and integration, correlation period of received reflected signals for separate antennas (directions) allows dramatically decreased ground clutter for low altitude flights. An open architecture, modular construction allows the combination of a radar sensor with Automatic Dependent Surveillance - Broadcast (ADS-B), electro-optic, acoustic sensors.

  7. Statistical modeling of phenological phases in Poland based on coupling satellite derived products and gridded meteorological data

    Science.gov (United States)

    Czernecki, Bartosz; Jabłońska, Katarzyna; Nowosad, Jakub

    2016-04-01

    The aim of the study was to create and evaluate different statistical models for reconstructing and predicting selected phenological phases. This issue is of particular importance in Poland where national-wide phenological monitoring was abandoned in the middle of 1990s and the reactivated network was established in 2006. Authors decided to evaluate possibilities of using a wide-range of statistical modeling techniques to create synthetic archive dataset. Additionally, a robust tool for predicting the most distinguishable phenophases using only free of charge data as predictors was created. Study period covers the years 2007-2014 and contains only quality-controlled dataset of 10 species and 14 phenophases. Phenological data used in this study originates from the manual observations network run by the Institute of Meteorology and Water Management - National Research Institute (IMGW-PIB). Three kind of data sources were used as predictors: (i) satellite derived products, (ii) preprocessed gridded meteorological data, and (iii) spatial properties (longitude, latitude, altitude) of the monitoring site. Moderate-Resolution Imaging Spectroradiometer (MODIS) level-3 vegetation products were used for detecting onset dates of particular phenophases. Following indices were used: Normalized Difference Vegetation Index (NDVI), Enhanced Vegetation Index (EVI), Leaf Area Index (LAI), and Fraction of Photosynthetically Active Radiation (fPAR). Additionally, Interactive Multisensor Snow and Ice Mapping System (IMS) products were chosen to detect occurrence of snow cover. Due to highly noisy data, authors decided to take into account pixel reliability information. Besides satellite derived products (NDVI, EVI, FPAR, LAI, Snow cover), a wide group of observational data and agrometeorological indices derived from the European Climate Assessment & Dataset (ECA&D) were used as a potential predictors: cumulative growing degree days (GDD), cumulative growing precipitation days (GPD

  8. Satellite quenching time-scales in clusters from projected phase space measurements matched to simulated orbits

    Science.gov (United States)

    Oman, Kyle A.; Hudson, Michael J.

    2016-12-01

    We measure the star formation quenching efficiency and time-scale in cluster environments. Our method uses N-body simulations to estimate the probability distribution of possible orbits for a sample of observed Sloan Digital Sky Survey galaxies in and around clusters based on their position and velocity offsets from their host cluster. We study the relationship between their star formation rates and their likely orbital histories via a simple model in which star formation is quenched once a delay time after infall has elapsed. Our orbit library method is designed to isolate the environmental effect on the star formation rate due to a galaxy's present-day host cluster from `pre-processing' in previous group hosts. We find that quenching of satellite galaxies of all stellar masses in our sample (109-10^{11.5}M_{⊙}) by massive (> 10^{13} M_{⊙}) clusters is essentially 100 per cent efficient. Our fits show that all galaxies quench on their first infall, approximately at or within a Gyr of their first pericentric passage. There is little variation in the onset of quenching from galaxy-to-galaxy: the spread in this time is at most ˜2 Gyr at fixed M*. Higher mass satellites quench earlier, with very little dependence on host cluster mass in the range probed by our sample.

  9. Multibeam Advisory Committee (MAC) - Three Years of Working Towards the Consistent Acquisition of High Quality Multibeam Echosounder Data Across the US Academic Fleet

    Science.gov (United States)

    Johnson, P. D.; Beaudoin, J. D.; Ferrini, V. L.

    2014-12-01

    In 2010 the National Science Foundation (NSF) held a meeting to address the variability in quality of multibeam echosounder (MBES) data for ships of the US Academic Fleet. The participants of this meeting identified that there was a strong need to coordinate operational efforts for multibeam data acquisition across all vessels of the fleet. To address this need, the University of New Hampshire's Center for Coastal and Ocean Mapping joined with Lamont-Doherty Earth Observatory in submitting a proposal to NSF to form the Multibeam Advisory Committee (MAC), which was funded in the fall of 2011. The MAC through the last three years has assembled a team of experts who have been called upon to respond to questions about MBES data acquisition and data quality, conduct shipboard assessments of MBES systems, create documentation supporting best practices for multibeam acquisition and data workflow, and to develop tools to support both data acquisition and quality assessment. Tools and techniques developed through the MAC include: SVP Editor - a graphical display and editing program for SVP, CTD, XBT, and XSV data. This program integrates directly with multibeam acquisition software to both receive navigation and depth information, used during the processing of the sound velocity data, and also has the ability to send edited and processed cast directly to the sounder. MBES Accuracy and Swath Performance Tools - tools which can assess both the accuracy of MBES bathymetric data as compared to a reference surface grid and to examine swath width performance of MBES systems as a function of depth. Remote Patch Test Support - the MAC provides patch test site selection, detailed execution plans, and tools to support the transmittal of a downsized raw MBES data files from ships over satellite in order to determine the angular offset values (pitch, heading, and roll) for MBES systems with no MAC personnel on board. Built In Self Test (BIST) Evaluation Tools - tools which can plot and

  10. Multi-beaming propertieis of reflector antennas used in radio telescopes with wide field of view

    CERN Document Server

    Iupikov, O

    2016-01-01

    The given work is devoted to the modern developments in the field of radio astronomy instrumentation. In particular, the sensitivity of the multi-beam reflector radio telescope which is fed by phased array (PAF) is considered. Using PAF as reflector feed allows obtaining wide and continuous field of view (FOV) of the telescope. This has several advantages with compare to horn-cluster feeds which are described in this work. The sensitivity inside whole FOV was computed using three different beamforming schemes.

  11. Trellis coding with Continuous Phase Modulation (CPM) for satellite-based land-mobile communications

    Science.gov (United States)

    1989-01-01

    This volume of the final report summarizes the results of our studies on the satellite-based mobile communications project. It includes: a detailed analysis, design, and simulations of trellis coded, full/partial response CPM signals with/without interleaving over various Rician fading channels; analysis and simulation of computational cutoff rates for coherent, noncoherent, and differential detection of CPM signals; optimization of the complete transmission system; analysis and simulation of power spectrum of the CPM signals; design and development of a class of Doppler frequency shift estimators; design and development of a symbol timing recovery circuit; and breadboard implementation of the transmission system. Studies prove the suitability of the CPM system for mobile communications.

  12. Arecibo Observations of Parkes Multibeam Pulsars

    Indian Academy of Sciences (India)

    N. D. R. Bhat; F. Camilo; J. M. Cordes; D. J. Nice; D. R. Lorimer; S. Chatterjee

    2002-03-01

    The on-going Parkes multibeam survey has been astoundingly successful (Manchester et al. 2001), and its discovery of over 600 pulsars has opened up new avenues for probing the Galaxy’s electron content and magnetic field. Here we report on recent observations made with the Arecibo 305-m telescope, where 80 distant, high dispersion measure pulsars (of which 35 are from the multibeam survey) were studied at multiple frequency bands in the range 0.4–2.4 GHz, in order to determine their scattering properties, rotation measures and spectral indices. The results will be used to meet a variety of science goals; viz., creating an improved model of the electron density, mapping out the Galactic magnetic field, and modeling the pulsar population.

  13. Exploitation of amplitude and phase of satellite SAR images for landslide mapping: the case of Montescaglioso (South Italy)

    Science.gov (United States)

    Raspini, Federico; Ciampalini, Andrea; Lombardi, Luca; Nocentini, Massimiliano; Gigli, Giovanni; Casagli, Nicola; Del Conte, Sara; Ferretti, Alessandro

    2016-04-01

    Pre- event and event landslide deformations have been detected and measured for the landslide that occurred on 3 December 2013 on the south-western slope of the Montescaglioso village (Basilicata Region, southern Italy). The event, triggered by prolonged rainfalls, created significant damage to buildings and local infrastructures. Ground displacements have been mapped through an integrated analysis based on a series of high resolution SAR (Synthetic Aperture Radar) images acquired by the Italian constellation of satellites COSMO-SkyMed. Analysis has been performed by exploiting both phase (through multi-image SAR interferometry) and amplitude information (through speckle tracking techniques) of the satellite images. SAR Interferometry, applied to images taken before the event, revealed a general pre-event movement, in the order of a few mm/yr, in the south-western slope of the Montescaglioso village. Highest pre-event velocities, ranging between 8 and 12 mm/yr, have been recorded in the sector of the slope where the first movement of the landslide took place. Speckle tracking, applied to images acquired before and after the event, allowed the retrieval of the 3D deformation field produced by the landslide. It also showed that ground displacements produced by the landslide have a dominant SSW component, with values exceeding 10 m for large sectors of the landslide area, with local peaks of 20 m in its central and deposit areas. Two minor landslides with a dominant SSE direction, which were detected in the upper parts of the slope, likely also occurred as secondary phenomena as consequence of the SSW movement of the main Montescaglioso landslide. This work demonstrates that this complementary approach, based on the synergistic exploitation of phase and amplitude SAR data, can become a powerful tool for landslide investigation, allowing the detection of slow, precursory deformation patterns as well the retrieval of full 3D surface displacement fields caused by large

  14. Reusable Reentry Satellite (RRS) system design study. Phase B, appendix E: Attitude control system study

    Science.gov (United States)

    1991-01-01

    A study which consisted of a series of design analyses for an Attitude Control System (ACS) to be incorporated into the Re-usable Re-entry Satellite (RRS) was performed. The main thrust of the study was associated with defining the control laws and estimating the mass and power requirements of the ACS needed to meet the specified performance goals. The analyses concentrated on the different on-orbit control modes which start immediately after the separation of the RRS from the launch vehicle. The three distinct on-orbit modes considered for these analyses are as follows: (1) Mode 1 - A Gravity Gradient (GG) three-axis stabilized spacecraft with active magnetic control; (2) Mode 2 - A GG stabilized mode with a controlled yaw rotation rate ('rotisserie') using three-axis magnetic control and also incorporating a 10 N-m-s momentum wheel along the (Z) yaw axis; and (3) Mode 3 - A spin stabilized mode of operation with the spin about the pitch (Y) axis, incorporating a 20 N-m-s momentum wheel along the pitch (Y) axis and attitude control via thrusters. To investigate the capabilities of the different controllers in these various operational modes, a series of computer simulations and trade-off analyses have been made to evaluate the achievable performance levels, and the necessary mass and power requirements.

  15. Satellite quenching timescales in clusters from projected phase space measurements matched to simulated orbits

    CERN Document Server

    Oman, Kyle A

    2016-01-01

    We measure the star formation quenching efficiency and timescale in cluster environments. Our method uses N-body simulations to estimate the probability distribution of possible orbits for a sample of observed SDSS galaxies in and around clusters based on their position and velocity offsets from their host cluster. We study the relationship between their star formation rates and their likely orbital histories via a simple model in which star formation is quenched once a delay time after infall has elapsed. Our orbit library method is designed to isolate the environmental effect on the star formation rate due to a galaxy's present-day host cluster from `pre-processing' in previous group hosts. We find that quenching of satellite galaxies of all stellar masses in our sample ($10^{9}-10^{11.5}\\,{\\rm M}_\\odot$) by massive ($> 10^{13}\\,{\\rm M}_\\odot$) clusters is essentially $100$ per cent efficient. Our fits show that all galaxies quench on their first infall, approximately at or within a Gyr of their first peric...

  16. Autonomous Satellite Command and Control through the World Wide Web: Phase 3

    Science.gov (United States)

    Cantwell, Brian; Twiggs, Robert

    1998-01-01

    NASA's New Millenium Program (NMP) has identified a variety of revolutionary technologies that will support orders of magnitude improvements in the capabilities of spacecraft missions. This program's Autonomy team has focused on science and engineering automation technologies. In doing so, it has established a clear development roadmap specifying the experiments and demonstrations required to mature these technologies. The primary developmental thrusts of this roadmap are in the areas of remote agents, PI/operator interface, planning/scheduling fault management, and smart execution architectures. Phases 1 and 2 of the ASSET Project (previously known as the WebSat project) have focused on establishing World Wide Web-based commanding and telemetry services as an advanced means of interfacing a spacecraft system with the PI and operators. Current automated capabilities include Web-based command submission, limited contact scheduling, command list generation and transfer to the ground station, spacecraft support for demonstrations experiments, data transfer from the ground station back to the ASSET system, data archiving, and Web-based telemetry distribution. Phase 2 was finished in December 1996. During January-December 1997 work was commenced on Phase 3 of the ASSET Project. Phase 3 is the subject of this report. This phase permitted SSDL and its project partners to expand the ASSET system in a variety of ways. These added capabilities included the advancement of ground station capabilities, the adaptation of spacecraft on-board software, and the expansion of capabilities of the ASSET management algorithms. Specific goals of Phase 3 were: (1) Extend Web-based goal-level commanding for both the payload PI and the spacecraft engineer; (2) Support prioritized handling of multiple PIs as well as associated payload experimenters; (3) Expand the number and types of experiments supported by the ASSET system and its associated spacecraft; (4) Implement more advanced resource

  17. Low-Cost Planar MM-Wave Phased Array Antenna for Use in Mobile Satellite (MSAT) Platforms

    DEFF Research Database (Denmark)

    Ojaroudiparchin, Naser; Shen, Ming; Pedersen, Gert F.

    2015-01-01

    In this paper, a compact 8×8 phased array antenna for mobile satellite (MSAT) devices is designed and investigated. 64-elements of 22 GHz patch antennas with coaxial-probe feeds have been used for the proposed planar design. The antenna is designed on a low-cost FR4 substrate with thickness......, dielectric constant, and loss tangent of 0.8 mm, 4.3, and 0.025, respectively. The antenna exhibits good performance in terms of impedance- matching, gain and efficiency characteristics, even though it is designed using high loss substrate with compact dimension (Wsub×Lsub=55×55 mm2). The antenna has more...... than 23 dB realized gain and -0.8 dB radiation efficiency when its beam is tilted to 0o elevation. The center frequency of the designed array can be controlled by adjusting the values of the antenna parameters. Compared with the previous designs, the proposed planar phased array has the advantages...

  18. Ka Band Phase Locked Loop Oscillator Dielectric Resonator Oscillator for Satellite EHF Band Receiver

    Directory of Open Access Journals (Sweden)

    S. Coco

    2008-01-01

    Full Text Available This paper describes the design and fabrication of a Ka Band PLL DRO having a fundamental oscillation frequency of 19.250 GHz, used as local oscillator in the low-noise block of a down converter (LNB for an EHF band receiver. Apposite circuital models have been created to describe the behaviour of the dielectric resonator and of the active component used in the oscillator core. The DRO characterization and measurements have shown very good agreement with simulation results. A good phase noise performance is obtained by using a very high Q dielectric resonator.

  19. Ka Band Phase Locked Loop Oscillator Dielectric Resonator Oscillator for Satellite EHF Band Receiver

    OpenAIRE

    Coco, S; Di Maggio, F.; A. Laudani; I. Pomona

    2008-01-01

    This paper describes the design and fabrication of a Ka Band PLL DRO having a fundamental oscillation frequency of 19.250 GHz, used as local oscillator in the low-noise block of a down converter (LNB) for an EHF band receiver. Apposite circuital models have been created to describe the behaviour of the dielectric resonator and of the active component used in the oscillator core. The DRO characterization and measurements have shown very good agreement with simulation results. A good phase nois...

  20. Technology Status and Developing Trends of Satellite Phased Array%星载相控阵天线的技术现状及发展趋势

    Institute of Scientific and Technical Information of China (English)

    阎鲁滨

    2012-01-01

    星载相控阵天线采用现代微波集成技术,在有限的卫星平台空间条件下,实现独立控制的多个点波束,满足未来通信的需求。相控阵天线可以实现波束间通信容量的调整,还可以根据需要改变波束形状,使用自适应调零的抗干扰技术,这些技术已在国外星上设备中广泛采用,具有广阔的发展前景。文章介绍了星载相控阵天线的研究现状、关键技术,以及发展趋势,并对我国星载相控阵天线技术的发展提出了建议。%Satellite phased array with modern microwave integrated circuit technology takes limit space on satellite and is able to independently control many beams to satisfy the demands ofmod- ern communication. The power ration between beams of phased array is adjustble. The radiation beam shape is variable and adaptive anti-jamming technology is easy to apply. Satellite phased ar- ray has been applied in wide domain and has increasing developing future. This paper gives the research status of satellite phased array, the key technologies and prospects the developing trends of satellite phased array.

  1. Galileo satellite antenna modeling

    Science.gov (United States)

    Steigenberger, Peter; Dach, Rolf; Prange, Lars; Montenbruck, Oliver

    2015-04-01

    The space segment of the European satellite navigation system Galileo currently consists of six satellites. Four of them belong to the first generation of In-Orbit Validation (IOV) satellites whereas the other two are Full Operational Capability (FOC) satellites. High-precision geodetic applications require detailed knowledge about the actual phase center of the satellite and receiver antenna. The deviation of this actual phase center from a well-defined reference point is described by phase center offsets (PCOs) and phase center variations (PCVs). Unfortunately, no public information is available about the Galileo satellite antenna PCOs and PCVs, neither for the IOV, nor the FOC satellites. Therefore, conventional values for the IOV satellite antenna PCOs have been adopted for the Multi-GNSS experiment (MGEX) of the International GNSS Service (IGS). The effect of the PCVs is currently neglected and no PCOs for the FOC satellites are available yet. To overcome this deficiency in GNSS observation modeling, satellite antenna PCOs and PCVs are estimated for the Galileo IOV satellites based on global GNSS tracking data of the MGEX network and additional stations of the legacy IGS network. Two completely independent solutions are computed with the Bernese and Napeos software packages. The PCO and PCV values of the individual satellites are analyzed and the availability of two different solutions allows for an accuracy assessment. The FOC satellites are built by a different manufacturer and are also equipped with another type of antenna panel compared to the IOV satellites. Signal transmission of the first FOC satellite has started in December 2014 and activation of the second satellite is expected for early 2015. Based on the available observations PCO estimates and, optionally PCVs of the FOC satellites will be presented as well. Finally, the impact of the new antenna model on the precision and accuracy of the Galileo orbit determination is analyzed.

  2. On the Adaptive Beam Forming Performance of a Multi-Beam Antenna

    Institute of Scientific and Technical Information of China (English)

    JIANGZe; DUHuiping; RUANYingzheng

    2004-01-01

    The adaptive beam forming performance of a new multi-beam adaptive antenna, which is configured by Fresnel zone phase-correcting plate (FZP) and uniformly spaced feeds array at FZP focusing plane, is investigated by considering the mobile to base station or reverse link in spread spectrum mobile communication scenes. With the specialized configuration of the antenna, the incoming wave signal maps from angular distribution to field distribution in the focal plane where the array is set. The“Beamformer-RAKE” receiver structure, which is suggested by existing CDMA standard, is used to evaluate the performance improvement of the suggested multi-beam antenna. The corresponding estimators for the beam-forming weight vector in the presence of angular spreads are derived out with the use of code filtering approach both in the case of M-ary orthogonal modulation with coherent and non-coherent RAKE combining receiver. Numerical simulation is used to compare the different bit error rate effects with the changes of angular spread, number of antennas and multipath structure both with the models of the one suggested here and the normal Uniformly spaced linear array (ULA) under the influence of co-channel interferences and white Gaussian noise. All the results suggest that the FZP-based multi-beam antenna have a better performance on adaptive beam forming in the specialized scenes.

  3. Measuring snow cover using satellite imagery during 1973 and 1974 melt season: North Santiam, Boise, and Upper Snake Basins, phase 1. [LANDSAT satellites, imaging techniques

    Science.gov (United States)

    Wiegman, E. J.; Evans, W. E.; Hadfield, R.

    1975-01-01

    Measurements are examined of snow coverage during the snow-melt season in 1973 and 1974 from LANDSAT imagery for the three Columbia River Subbasins. Satellite derived snow cover inventories for the three test basins were obtained as an alternative to inventories performed with the current operational practice of using small aircraft flights over selected snow fields. The accuracy and precision versus cost for several different interactive image analysis procedures was investigated using a display device, the Electronic Satellite Image Analysis Console. Single-band radiance thresholding was the principal technique employed in the snow detection, although this technique was supplemented by an editing procedure involving reference to hand-generated elevation contours. For each data and view measured, a binary thematic map or "mask" depicting the snow cover was generated by a combination of objective and subjective procedures. Photographs of data analysis equipment (displays) are shown.

  4. Subcarrier phase recovery performance in bent-pipe mode of Shuttle data transmission. [on Tracking and Data Relay Satellite System Ku-band return link

    Science.gov (United States)

    Mckenzie, T. M.; Braun, W. R.

    1978-01-01

    The subcarrier phase recovery is analyzed for the bent-pipe mode of Space Shuttle detached-payload data transmission on the Tracking and Data Relay Satellite System (TDRSS) Ku-band return link. The high-power component of the subcarrier modulation is unrestored payload data, either at baseband or modulating another subcarrier. At the receiver a Costas loop recovers the subcarrier phase. To analyze its performance in the baseband case, we obtain the loop S-curve, the power spectral density of the equivalent noise process, and the loop phase error variance.

  5. Maskless lithography and nanopatterning with electron and ion multibeam projection

    Science.gov (United States)

    Platzgummer, Elmar

    2010-03-01

    Multi-beam writing becomes mandatory in order to stay within reasonable realization times for the fabrication of leading-edge complex masks and templates. IMS Nanofabrication has developed multi-beam projection techniques implementing a programmable aperture plate system (APS) and charged-particle projection optics with 200x reduction. Proof-of-concept of multi-beam writing was demonstrated in 2009 with 10 keV ion multi-beams and 50 keV electron multi-beams using 43-thousand and 2.5-thousand, respectively, programmable 12.5nm sized beams. In Q4 2009 the development of a 50 keV electron multi-beam Mask Exposure Tool (eMET) was started with the aim to realize 256-thousand programmable 20 nm and 10 nm sized beams. The eMET column realization will provide important synergies for the development of projection mask-less lithography (PML2) for direct write on wafers. In order to enhance throughput a Multi-Axis-PML2 scheme is put forward with potential throughput of 5 WPH for the 16 nm hp technology node and below. Clustering such maskless tools a throughput of 50-100 WPH within a scanner floor space is envisioned. Ion multi-beam techniques may be applied for 2.5D / 3D template fabrication and resistless nanopatterning.

  6. 相位噪声对8PSK卫星通信链路的影响%Effect of Phase Noise on Link of Satellite Communication

    Institute of Scientific and Technical Information of China (English)

    张金贵; 许星辰

    2014-01-01

    研究了相位噪声对卫星通信链路传输性能的影响,给出了相位噪声的数字模拟方法,设计了卫星通信链路的基带等效仿真模型,结合8移相键控(8 Phase Shift Keying,8PSK)调制方式及低密度奇偶校验码(Low Density Parity Code,LDPC),仿真了相位噪声频谱特性对卫星通信链路传输性能所造成的恶化。仿真结果表明,当卫星通信链路的相位噪声特性变差时,会影响链路传输性能,甚至会出现误码平台。%With the effect of phase noise on transmission characteristics of the link of satellite communication researched,the numerical simulation means of phase noise is proposed,the base-band equivalent simulation model of satellite communication link is designed,and the effect of phase noise on transmission characteristics of the link of satellite communication is simulated with 8PSK modulation and LDPC error correction.The simulation results show that when the phase noise of the link of satellite communication is worse,the transmission characteristic is affected,and the error-floor is formed even.

  7. Seafloor Sediment Classification Based on Multibeam Sonar Data

    Institute of Scientific and Technical Information of China (English)

    ZHOU Xinghua; CHEN Yongqi

    2004-01-01

    The multibeam sonars can provide hydrographic quality depth data as well as hold the potential to provide calibrated measurements of the seafloor acoustic backscattering strength. There has been much interest in utilizing backscatters and images from multibeam sonar for seabed type identification and most results are obtained. This paper has presented a focused review of several main methods and recent developments of seafloor classification utilizing multibeam sonar data or/and images. These are including the power spectral analysis methods, the texture analysis, traditional Bayesian classification theory and the most active neural network approaches.

  8. Theoretical and experimental research on multi-beam klystron

    Science.gov (United States)

    Yaogen, Ding; Jun, Peng; Yunshu, Zhu; Shaoming, Shi

    1999-05-01

    Theoretical and experimental research work on multi-beam klystron (MBK) conducted in Institute of Electronics, Chinese Academy of Sciences (IECAS) is described in this paper. Research progress on Interaction between multi-electron beam and microwave electric field, multi-beam cavity, filter loaded double gap cavity broadband output circuit, multi-beam electron gun, and periodic reversal focusing system is presented. Performance and measurement results of five types of MBK are also given out. The key technical problems for present MBK are discussed in this paper.

  9. Application of modified multiple subarrays detection method to multibeam bathymetry system

    Institute of Scientific and Technical Information of China (English)

    ZHOU Tian; LI Hai-sen; ZHU Zhi-de; YUAN Yan-yi

    2005-01-01

    Either amplitude based methods or phase based methods are usually used in multibeam bathymetry system and chosen in practical measurement by ad hoc criteria. The errors of the detection are often caused by choosing wrong detection method. In this paper a modified multiple subarrays amplitude-phase united detection method is proposed , which uses both the amplitude and phase of echo from bottom.This new method not only realizes the super-wide swath coverage, but also improves the detection performance by using the phase differences among subarrays in place of phases of subarrays to estimate the phase slope image. Experimental results are also analyzed and discussed to demonstrate the effectivity of the proposed approach.

  10. A Beam Tracking Algorithm Based on Satellite Beacon Signals for Phased Array in Mobile Satellite Communications%一种基于信标的移动卫通相控阵波束跟踪算法

    Institute of Scientific and Technical Information of China (English)

    陈鹏; 张慧

    2012-01-01

    In this paper a beam tracking algorithm based on satellite beacon signals is proposed and realized. The method is suitable for all kinds of phased array type mobile satellite communication antennas. It overcomes the difficulty of detecting the extremely weak satellite beacon signals and then the tracking performance is greatly improved. The highlight of the algorithm is the beam tracking process can be run without the help of gyroscopes and thus improves the survivability in the extreme environments. The algorithm was implemented and verified in a Ku band phased array mobile satellite antenna.%提出并实现了一种利用卫星信标信号来实施基于相控阵天线的波束跟踪算法。该方法适用于采用相控阵天线技术的各种卫星“动中通”天线,克服了卫星信标信号强度弱,检测困难的弱点,提高了跟踪信噪比,同时采用了软件无线电方式解调可以提供最大的灵活性。跟踪算法的最大优点是没有任何陀螺仪的辅助,极大地提高了天线在各种极端运动环境下的适应能力。算法最终在自行研制的Ku波段相控阵移动卫星天线系统上获得验证。

  11. The Multibeam Advisory Committee (MAC): a search for solutions for collecting consistent high quality multibeam data across multiple ships, systems, and operators in the U.S. Academic Fleet.

    Science.gov (United States)

    Johnson, P. D.; Ferrini, V. L.; Jerram, K.

    2016-12-01

    In 2015 the National Science Foundation funded the University of New Hampshire's Center for Coastal and Ocean Mapping and Lamont-Doherty Earth Observatory, for the second time, to coordinate the effort of standardizing the quality of multibeam echosounder (MBES) data across the U.S. academic fleet. This effort supports 9 different ship operating institutions who manage a total of 12 multibeam-equipped ships carrying 6 different MBES systems, manufactured by two different companies. These MBES are designed to operate over a very wide range of depths and operational modes. The complexity of this endeavor led to the creation of the Multibeam Advisory Committee (MAC), a team of academic and industry experts whose mission is to support the needs of the U.S academic fleet's multibeam echo sounders through all of the phases of the "life" of a MBES system and its data, from initial acceptance of the system, to recommendations on at-sea acquisition of data, to validation of already installed systems, and finally to the post-survey data evaluation. The main activities of the MAC include 1.) standardizing both the Shipboard Acceptance Testing of all new systems and Quality Assurance Testing of already installed systems, 2.) working with the both the ship operators/technicians and the manufacturers of the multibeam systems to guarantee that each MBES is working at its peak performance level, 3.) developing tools that aid in the collection of data, assessment of the MBES hardware, and evaluation of the quality of the MBES data, 4.) creating "best practices" documentation concerning data acquisition and workflow, and 5.) providing a website, http://mac.unols.org, to host technical information, tools, reports, and a "help desk" for operators of the systems to ask questions concerning issues that they see with their systems.

  12. NOAA Ship Pisces Cruise PC1106 (14) Multibeam Sonar Workshop

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The overall objective is to familiarize participating scientists with PISCES multibeam echosounder (Simrad ME70) configuration, operation, calibration and data...

  13. Reson 8101 multibeam backscatter data from Galvez Bank.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Multibeam backscatter imagery extracted from gridded bathymetry of the Mariana archipelago between the U.S. Territory of Guam and Farallon De Pajaros Island in the...

  14. Study of multibeam techniques for bathymetry and seabottom backscatter applications

    Digital Repository Service at National Institute of Oceanography (India)

    Nair, R.R.; Chakraborty, B.

    In this paper, a brief discussion is carried out on the application of the different techniques of echosounding. A deteiled appraisal of the presently used multibeam technique is mentioned. Some of the important discoveries of seabed features around...

  15. February 2007 Multibeam Mapping of Pulley Ridge, southwest Florida

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This disk or set of disks contain high-resolution multibeam and backscatter maps of the Pulley Ridge Area, near the Tortugas, in the Gulf of Mexico. It includes the...

  16. Seafloor character from multibeam echo sounder data-Santa Barbara Channel

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Substrate was classified using the method of (Cochrane 2008) for this study multibeam sonar. Sea floor character derived from multibeam sonar data is available for...

  17. Seafloor character from multibeam echo sounder data-Santa Barbara Channel

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Substrate was classified using the method of (Cochrane 2008) for this study multibeam sonar. Sea floor character derived from multibeam sonar data is available for...

  18. Comparison of Airborne Lidar and Multibeam Bathymetric Data in the Florida Reef Tract Along Broward County

    Science.gov (United States)

    Morton, N. E.; Burd, J. J.

    2003-12-01

    Although large, well-known concentrations of corals are found in deeper waters off Florida's eastern seaboard, most mapping of Florida's coral resources addresses the relatively shallow waters of the Florida Keys. To date, technological limitations precluded mapping corals in these deeper waters. Satellite imaging systems and natural color aerial photography, two mapping mainstays, are generally only effective in Florida waters shallower than 20 meters. Conservation of the northern portion of the Florida reef tract, which parallels the Atlantic coast in Miami-Dade, Broward, and Palm Beach counties, has been hampered by minimal or nonexistent coordinated management, monitoring, and mapping activities. In November 2000, the Simrad EM3000 multibeam system was used to collect data south of Port Everglades. Additionally, the Broward County shore protection project conducted a Laser Airborne Depth Sounder (LADS) survey in 2001. Wavelet analyses performed on overlapping transects of the two data sets compare the accuracy of reef bathymetry and complexity captured in the two data collection projects.

  19. Contrast enhanced exposure strategy in multi-beam mask writing

    Science.gov (United States)

    Belic, Nikola; Hofmann, Ulrich; Klikovits, Jan; Martens, Stephan

    2013-03-01

    Since multi electron beam exposure has become a serious contender for next generation mask making, proximity- and process effect corrections (PEC) need to be adapted to this technology. With feature sizes in the order of the short-range blurs (resist and tool), contrast enhancements need to be combined with standard linearity corrections. Different PEC strategies are reviewed and compared with respect to their suitability for multi-beam exposure. This analysis recommends a hybrid approach that combines the benefits of shape- and dose PEC and is optimally applicable for multibeam exposure. Exposure results on the proof-of-concept 50keV electron multi-beam mask exposure tool (eMET POC) and a standard 50 kV vector shaped beam tool (VSB) are shown to verify that the combined PEC with overdose contrast enhancement covers the whole pattern range from isolated to opaque.

  20. Network coding and its applications to satellite systems

    DEFF Research Database (Denmark)

    Vieira, Fausto; Roetter, Daniel Enrique Lucani

    2015-01-01

    Network coding has its roots in information theory where it was initially proposed as a way to improve a two-node communication using a (broadcasting) relay. For this theoretical construct, a satellite communications system was proposed as an illustrative example, where the relay node would...... be a satellite covering the two nodes. The benefits in terms of throughput, resilience, and flexibility of network coding are quite relevant for wireless networks in general, and for satellite systems in particular. This chapter presents some of the basics in network coding, as well as an overview of specific...... scenarios where network coding provides a significant improvement compared to existing solutions, for example, in broadcast and multicast satellite networks, hybrid satellite-terrestrial networks, and broadband multibeam satellites. The chapter also compares coding perspectives and revisits the layered...

  1. Network coding and its applications to satellite systems

    DEFF Research Database (Denmark)

    Vieira, Fausto; Roetter, Daniel Enrique Lucani

    2015-01-01

    Network coding has its roots in information theory where it was initially proposed as a way to improve a two-node communication using a (broadcasting) relay. For this theoretical construct, a satellite communications system was proposed as an illustrative example, where the relay node would...... be a satellite covering the two nodes. The benefits in terms of throughput, resilience, and flexibility of network coding are quite relevant for wireless networks in general, and for satellite systems in particular. This chapter presents some of the basics in network coding, as well as an overview of specific...... scenarios where network coding provides a significant improvement compared to existing solutions, for example, in broadcast and multicast satellite networks, hybrid satellite-terrestrial networks, and broadband multibeam satellites. The chapter also compares coding perspectives and revisits the layered...

  2. Satellite Communication.

    Science.gov (United States)

    Technology Teacher, 1985

    1985-01-01

    Presents a discussion of communication satellites: explains the principles of satellite communication, describes examples of how governments and industries are currently applying communication satellites, analyzes issues confronting satellite communication, links mathematics and science to the study of satellite communication, and applies…

  3. Satellite-aided mobile radio concepts study: Concept definition of a satellite-aided mobile and personal radio communication system

    Science.gov (United States)

    Anderson, R. E.

    1979-01-01

    The satellite system requires the use of a large satellite antenna and spacecraft array power of about 12 kW or more depending on the operating frequency. Technology developments needed include large offset reflector multibeam antennas, satellite electrical power sybsystems providing greater than 12 kW of power, signal switching hardware, and linearized efficient solid state amplifiers for the satellite-aided mobile band. Presently there is no frequency assignment for this service, and it is recommended that an allocation be pursued. The satellite system appears to be within reasonable extrapolation of the state of the art. It is further recommended that the satellite-aided system spacecraft definition studies and supporting technology development be initiated.

  4. Mobile satellite service for Canada

    Science.gov (United States)

    Sward, David

    1988-05-01

    The Mobile Satellite (MSAT) system and a special program designed to provide interim mobile satellite services (IMSS) during the construction phase of MSAT are described. A mobile satellite system is a key element in extending voice and and data telecommunications to all Canadians.

  5. Patterning of Aluminium thin film on polyethylene terephthalate by multi-beam picosecond laser

    Science.gov (United States)

    Jin, Y.; Perrie, W.; Harris, P.; Allegre, O. J.; Abrams, K. J.; Dearden, G.

    2015-11-01

    High speed patterning of a 30 nm thick Aluminium thin film on a flexible Polyethylene Terephthalate substrate was demonstrated with the aid of Computer Generated Holograms (CGH's) applied to a phase only Spatial Light Modulator. Low fluence picosecond laser pulses minimise thermal damage to the sensitive substrate and thus clean, single and multi-beam, front side thin film removal is achieved with good edge quality. Interestingly, rear side ablation shows significant Al film delamination. Measured front and rear side ablation thresholds were Fth=0.20±0.01 J cm-2 and Fth=0.15±0.01 J cm-2 respectively. With laser repetition rate of 200 kHz and 8 diffractive spots, a film removal rate of R>0.5 cm2 s-1 was demonstrated during patterning with a fixed CGH and 5 W average laser power. The effective laser repetition rate was feff~1.3 MHz. The application of 30 stored CGH's switching up to 10 Hz was also synchronised with motion control, allowing dynamic large area multi-beam patterning which however, slows micro-fabrication.

  6. Optical image encryption based on multi-beam interference and common vector decomposition

    Science.gov (United States)

    Chen, Linfei; He, Bingyu; Chen, Xudong; Gao, Xiong; Liu, Jingyu

    2016-02-01

    Based on multi-beam interference and common vector decomposition, we propose a new method for optical image encryption. In encryption process, the information of an original image is encoded into n amplitude masks and n phase masks which are regarded as a ciphertext and many keys. In decryption process, parallel light irradiates the amplitude masks and phase masks, then passes through lens that takes place Fourier transform, and finally we obtain the original image at the output plane after interference. The security of the encryption system is also discussed in the paper, and we find that only when all the keys are correct, can the information of the original image be recovered. Computer simulation results are presented to verify the validity and the security of the proposed method.

  7. 'Taking X-ray phase contrast imaging into mainstream applications' and its satellite workshop 'Real and reciprocal space X-ray imaging'.

    Science.gov (United States)

    Olivo, Alessandro; Robinson, Ian

    2014-03-06

    A double event, supported as part of the Royal Society scientific meetings, was organized in February 2013 in London and at Chicheley Hall in Buckinghamshire by Dr A. Olivo and Prof. I. Robinson. The theme that joined the two events was the use of X-ray phase in novel imaging approaches, as opposed to conventional methods based on X-ray attenuation. The event in London, led by Olivo, addressed the main roadblocks that X-ray phase contrast imaging (XPCI) is encountering in terms of commercial translation, for clinical and industrial applications. The main driver behind this is the development of new approaches that enable XPCI, traditionally a synchrotron method, to be performed with conventional laboratory sources, thus opening the way to its deployment in clinics and industrial settings. The satellite meeting at Chicheley Hall, led by Robinson, focused on the new scientific developments that have recently emerged at specialized facilities such as third-generation synchrotrons and free-electron lasers, which enable the direct measurement of the phase shift induced by a sample from intensity measurements, typically in the far field. The two events were therefore highly complementary, in terms of covering both the more applied/translational and the blue-sky aspects of the use of phase in X-ray research. 

  8. The Phase Space and Stellar Populations of Cluster Galaxies at z ~ 1: Simultaneous Constraints on the Location and Timescale of Satellite Quenching

    CERN Document Server

    Muzzin, Adam; McGee, Sean L; Balogh, Michael; Franx, Marijn; Hoekstra, Henk; Hudson, Michael J; Noble, Allison; Taranu, Dan; Webb, Tracy; Wilson, Gillian; Yee, H K C

    2014-01-01

    We investigate the velocity vs. position phase space of z ~ 1 cluster galaxies using a set of 424 spectroscopic redshifts in 9 clusters drawn from the GCLASS survey. Dividing the galaxy population into three categories: quiescent, star-forming, and poststarburst, we find that these populations have distinct distributions in phase space. Most striking are the poststarburst galaxies, which are commonly found at small clustercentric radii with high clustercentric velocities, and appear to trace a coherent ``ring" in phase space. Using several zoom simulations of clusters we show that the coherent distribution of the poststarbursts can be reasonably well-reproduced using a simple quenching scenario. Specifically, the phase space is best reproduced if satellite quenching occurs on a rapid timescale (0.1 < tau_{Q} < 0.5 Gyr) after galaxies make their first passage of R ~ 0.5R_{200}, a process that takes a total time of ~ 1 Gyr after first infall. We compare this quenching timescale to the timescale implied by...

  9. A New Method For Processing Backscatter Imagery Collected By Multibeam Sonars: The HAWAII MR1 Sidescan Sonar Software Suite

    Science.gov (United States)

    Davis, R.; Appelgate, B.

    2003-12-01

    The Hawaii Mapping Research Group of the University of Hawaii has developed and used in-house software to process seafloor acoustic imagery (sidescan sonar) data acquired by its own shallow-towed HAWAII-MR1 phase-difference sidescan bathymetry mapping system, as well as phase-difference sonars operated by other institutions (NAVO SEAMAP-C, LDEO SCAMP, WHOI DSL-120A). During 2003 the HAWAII MR1 software tools were modified to operate on multibeam backscatter data collected by the University of Hawaii research vessel Kilo Moana to test whether the software could improve the quality of the multibeam backscatter and the resulting data products. We found that the MR1 processing tools are effective in eliminating speckle and stripe noise, and cross-track amplitude variability due to angle-varying gain. HMRG software was also used to produce final mosaics of sonar imagery. Once we determined the viability of using the MR1 tools to process Kilo Moana data, we expanded the toolkit to allow operation on data from other multibeam systems as well. HMRG processing software runs on Linux, Unix and Irix platforms. The main processing modules can be run in either graphical or command-line modes. The preferred processing scheme involves using the graphical interface to interactively determine noise filters appropriate for each survey. Once characterized, these filters are then applied in batch processes that run faster than graphical methods allow. Once processing is completed, the HMRG software is used to grid the data and then to assemble individual grids into mosaics. The mosaics can be output as Sun raster files, geotiffs, or Generic Mapping Tools (GMT) grids, which allow the mosaics to be imported into other GIS and charting programs. Here we present results from several recent surveys that used different hull-mounted multibeam systems: 12kHz Sea Beam 2112 data from the US Coast Guard Cutter Healy, 12kHz Simrad EM120 data from deep water surveys aboard the R/V Kilo Moana

  10. Improving Multi-Beam Echo Sounder Depth Measurements

    NARCIS (Netherlands)

    Snellen, M.; Ameele, J.J.P. van den; Biersteker, R.; Simons, D.G.

    2006-01-01

    An important research question is how to adequately correct multi-beam echo sounder (MBES) bathymetric data for refraction effects. This is especially relevant for survey areas, like the Maasgeul area off the Dutch coast, where the water column properties and thus the prevailing sound speed profile

  11. Novel multi-beam radiometers for accurate ocean surveillance

    DEFF Research Database (Denmark)

    Cappellin, C.; Pontoppidan, K.; Nielsen, P. H.

    2014-01-01

    Novel antenna architectures for real aperture multi-beam radiometers providing high resolution and high sensitivity for accurate sea surface temperature (SST) and ocean vector wind (OVW) measurements are investigated. On the basis of the radiometer requirements set for future SST/OVW missions...

  12. Leaky Wave Enhanced Feeds for Multi-Beam Reflector Systems

    NARCIS (Netherlands)

    Neto, A.; Gerini, G.; Llombart, N.; Ettorre, M.; Maagt, P. de

    2011-01-01

    Abstract—This paper discusses the use of dielectric superlayers to shape the radiation pattern of focal plane feeds of a multi-beam reflector system. The shaping of the pattern is obtained by exciting a pair (TE/TM) of leaky waves that radiate incrementally as they propagate between the ground plane

  13. Comparison of Shallow Survey 2012 Multibeam Datasets

    Science.gov (United States)

    Ramirez, T. M.

    2012-12-01

    The purpose of the Shallow Survey common dataset is a comparison of the different technologies utilized for data acquisition in the shallow survey marine environment. The common dataset consists of a series of surveys conducted over a common area of seabed using a variety of systems. It provides equipment manufacturers the opportunity to showcase their latest systems while giving hydrographic researchers and scientists a chance to test their latest algorithms on the dataset so that rigorous comparisons can be made. Five companies collected data for the Common Dataset in the Wellington Harbor area in New Zealand between May 2010 and May 2011; including Kongsberg, Reson, R2Sonic, GeoAcoustics, and Applied Acoustics. The Wellington harbor and surrounding coastal area was selected since it has a number of well-defined features, including the HMNZS South Seas and HMNZS Wellington wrecks, an armored seawall constructed of Tetrapods and Akmons, aquifers, wharves and marinas. The seabed inside the harbor basin is largely fine-grained sediment, with gravel and reefs around the coast. The area outside the harbor on the southern coast is an active environment, with moving sand and exposed reefs. A marine reserve is also in this area. For consistency between datasets, the coastal research vessel R/V Ikatere and crew were used for all surveys conducted for the common dataset. Using Triton's Perspective processing software multibeam datasets collected for the Shallow Survey were processed for detail analysis. Datasets from each sonar manufacturer were processed using the CUBE algorithm developed by the Center for Coastal and Ocean Mapping/Joint Hydrographic Center (CCOM/JHC). Each dataset was gridded at 0.5 and 1.0 meter resolutions for cross comparison and compliance with International Hydrographic Organization (IHO) requirements. Detailed comparisons were made of equipment specifications (transmit frequency, number of beams, beam width), data density, total uncertainty, and

  14. Multibeam Bathymetry of Haleakala Volcano, Maui

    Science.gov (United States)

    Eakins, B. W.; Robinson, J.

    2002-12-01

    The submarine northeast flank of Haleakala Volcano, Maui was mapped in detail during the summers of 2001 and 2002 by a joint team from the Japan Marine Science and Technology Center (JAMSTEC), Tokyo Institute of Technology, University of Hawaii, and the U.S. Geological Survey. JAMSTEC instruments used included SeaBeam 2112 hull-mounted multibeam sonar (bathymetry and sidescan imagery), manned submersible Shinkai 6500 and ROV Kaiko (bottom video, photographs and sampling of Hana Ridge), gravimeter, magnetometer, and single-channel seismic system. Hana Ridge, Haleakala's submarine east rift zone, is capped by coral-reef terraces for much of its length, which are flexurally tilted towards the axis of the Hawaiian Ridge and delineate former shorelines. Its deeper, more distal portion exhibits a pair of parallel, linear crests, studded with volcanic cones, that suggest lateral migration of the rift zone during its growth. The northern face of the arcuate ridge terminus is a landslide scar in one of these crests, while its southwestern prong is a small, constructional ridge. The Hana slump, a series of basins and ridges analogous to the Laupahoehoe slump off Kohala Volcano, Hawaii, lies north of Hana Ridge and extends down to the Hawaiian moat. Northwest of this slump region a small, dual-crested ridge strikes toward the Hawaiian moat and is inferred to represent a fossil rift zone, perhaps of East Molokai Volcano. A sediment chute along its southern flank has built a large submarine fan with a staircase of contour-parallel folds on its surface that are probably derived from slow creep of sediments down into the moat. Sediments infill the basins of the Hana slump [Moore et al., 1989], whose lowermost layers have been variously back-tilted by block rotation during slumping and flexural loading of the Hawaiian Ridge; the ridges define the outer edges of those down-dropped blocks, which may have subsided several kilometers. An apron of volcaniclastic debris shed from

  15. The phase space and stellar populations of cluster galaxies at z ∼ 1: simultaneous constraints on the location and timescale of satellite quenching

    Energy Technology Data Exchange (ETDEWEB)

    Muzzin, Adam; Van der Burg, R. F. J.; McGee, Sean L.; Balogh, Michael; Franx, Marijn; Hoekstra, Henk [Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden (Netherlands); Hudson, Michael J. [Department of Physics and Astronomy, University of Waterloo, Waterloo, ON N2L 3G1 (Canada); Noble, Allison; Taranu, Dan S.; Yee, H. K. C. [Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, ON M5S 3H4 (Canada); Webb, Tracy [Department of Physics, McGill University, Montréal, QC (Canada); Wilson, Gillian [Department of Physics and Astronomy, University of California, Riverside, CA 92521 (United States)

    2014-11-20

    We investigate the velocity versus position phase space of z ∼ 1 cluster galaxies using a set of 424 spectroscopic redshifts in nine clusters drawn from the GCLASS survey. Dividing the galaxy population into three categories, that is, quiescent, star-forming, and poststarburst, we find that these populations have distinct distributions in phase space. Most striking are the poststarburst galaxies, which are commonly found at small clustercentric radii with high clustercentric velocities, and appear to trace a coherent 'ring' in phase space. Using several zoom simulations of clusters, we show that the coherent distribution of the poststarbursts can be reasonably well reproduced using a simple quenching scenario. Specifically, the phase space is best reproduced if these galaxies are quenched with a rapid timescale (0.1 <τ {sub Q} < 0.5 Gyr) after they make their first passage of R ∼ 0.5 R {sub 200}, a process that takes a total time of ∼1 Gyr after first infall. The poststarburst phase space is not well reproduced using long quenching timescales (τ {sub Q} > 0.5 Gyr) or by quenching galaxies at larger radii (R ∼ R {sub 200}). We compare this quenching timescale to the timescale implied by the stellar populations of the poststarburst galaxies and find that the poststarburst spectra are well-fit by a rapid quenching (τ {sub Q} = 0.4{sub −0.4}{sup +0.3} Gyr) of a typical star-forming galaxy. The similarity between the quenching timescales derived from these independent indicators is a strong consistency check of the quenching model. Given that the model implies satellite quenching is rapid and occurs well within R {sub 200}, this would suggest that ram-pressure stripping of either the hot or cold gas component of galaxies are the most plausible candidates for the physical mechanism. The high cold gas consumption rates at z ∼ 1 make it difficult to determine whether hot or cold gas stripping is dominant; however, measurements of the redshift

  16. Design and characteristics of a multiband communication satellite antenna system

    Science.gov (United States)

    Ueno, Kenji; Itanami, Takao; Kumazawa, Hiroyuki; Ohtomo, Isao

    1995-04-01

    Feasibility studies on a multiband communication satellite antenna system and the key technologies involved in devising this system are described. The proposed multiband communication satellite utilizes four frequency bands: Ka (30/20 GHz), Ku (14/12 GHz), C (6/4 GHz), and S (2.6/2.5 GHz). It has six beam configurations, three multibeam and three shaped-beam. The following key technologies are presented: (1) a low-loss frequency selective subreflector (FSR) for compact feeds, (2) a low-loss and broadband frequency selective surface (FSS), and (3) a highly accurate and reliable mesh reflector.

  17. The Phase Space and Stellar Populations of Cluster Galaxies at z ~ 1: Simultaneous Constraints on the Location and Timescale of Satellite Quenching

    Science.gov (United States)

    Muzzin, Adam; van der Burg, R. F. J.; McGee, Sean L.; Balogh, Michael; Franx, Marijn; Hoekstra, Henk; Hudson, Michael J.; Noble, Allison; Taranu, Dan S.; Webb, Tracy; Wilson, Gillian; Yee, H. K. C.

    2014-11-01

    We investigate the velocity versus position phase space of z ~ 1 cluster galaxies using a set of 424 spectroscopic redshifts in nine clusters drawn from the GCLASS survey. Dividing the galaxy population into three categories, that is, quiescent, star-forming, and poststarburst, we find that these populations have distinct distributions in phase space. Most striking are the poststarburst galaxies, which are commonly found at small clustercentric radii with high clustercentric velocities, and appear to trace a coherent "ring" in phase space. Using several zoom simulations of clusters, we show that the coherent distribution of the poststarbursts can be reasonably well reproduced using a simple quenching scenario. Specifically, the phase space is best reproduced if these galaxies are quenched with a rapid timescale (0.1 0.5 Gyr) or by quenching galaxies at larger radii (R ~ R 200). We compare this quenching timescale to the timescale implied by the stellar populations of the poststarburst galaxies and find that the poststarburst spectra are well-fit by a rapid quenching (τ Q = 0.4+0.3-0.4 Gyr) of a typical star-forming galaxy. The similarity between the quenching timescales derived from these independent indicators is a strong consistency check of the quenching model. Given that the model implies satellite quenching is rapid and occurs well within R 200, this would suggest that ram-pressure stripping of either the hot or cold gas component of galaxies are the most plausible candidates for the physical mechanism. The high cold gas consumption rates at z ~ 1 make it difficult to determine whether hot or cold gas stripping is dominant; however, measurements of the redshift evolution of the satellite quenching timescale and location may be capable of distinguishing between the two. Based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on

  18. Bathymetry, Multibeam, and Coastal Relief: Data on Demand

    Science.gov (United States)

    Sharman, G. F.; Virden, W. T.; Divins, D. L.; Fox, C. G.; Habermann, T.

    2004-12-01

    The National Oceanic and Atmospheric Administration's (NOAA) National Geophysical Data Center (NGDC), Boulder, Colorado is distributing increasing quantities of data via the Internet. With evolving technology and broader bandwidth, it is possible to deliver large volumes (up to 2 GB) of data directly over the Internet and to provide server-side-generated products and services with more user options. In 2004, NGDC (www.ngdc.noaa.gov) initiated a web-based multibeam bathymetric data system,leveraging off geospatial and relational database technologies being utilized at the Center. The system has an ESRI ArcIMS interface, which handles the geospatial character of the data, and provides a standardized GIS interface and tool suite. All of this rests on a foundation Oracle database containing an inventory and metadata. It also uses software developed at NOAA's Pacific Marine Environmental Laboratory, which scripts the National Science Foundation-supported software packages: MBSystem (for managing multibeam data) and Generic Mapping Tools (GMT) (for mapping and display). In whole, the MultiBeam Bathymetric Data Base (MBBDB) (Virden, et al., "Multibeam Bathymetric Data at NOAA/NGDC," OTO '04) enables the web user to browse, discover, review, select, map, and download multibeam data directly, without human intervention by NGDC. A similar development, the NGDC Coastal Relief Model (CRM), http://www.ngdc.noaa.gov/mgg/coastal/coastal.html, is available for download at a variety of sampling intervals. This data set is built on multibeam and conventional offshore hydrography, resampled into a 3 arc-second lat-lon grid, which is matched to a 3 arc-second version of the USGS National Elevation Database (NED). The resulting fusion gives a continuous elevation surface model from the seafloor, across the coastline and onto the land. These data provide the foundation for a multitude of environmental studies and models, such as Tsunami or storm surge propagation, run up, and inundation

  19. Adaptive beam forming for time-variant channels with a multi-beam antenna

    Institute of Scientific and Technical Information of China (English)

    JIANG Ze; MEI Yuan-yuan; RUAN Wei

    2008-01-01

    A multi-beam adaptive antenna is investigated by considering the adaptive beam forming performance for time-variant channels on the focus of mobile to base station or reverse link. This antenna is constructed by Fresnel zone phase-correcting plane (FZP) focusing element and uniformly spaced feeds array. An estimator for the beamforming weight vector in the presence of angle spreads is derived using a code filtering approach. Owing to the time-varying nature of the channels, a recursive method for computing and tracking the above optimal weight vector solution that is easy to implement is applied. The effects of angle spread, maximum Doppler frequency, and forgetting factor are studied. Simulation results showed that this type of adaptive antenna is capable of performing adaptive beam forming for time-variant channels effectively.

  20. Multi-beam laser beacon propagation over lunar distance: comparison of predictions and measurements

    Science.gov (United States)

    Biswas, A.; Piazzolla, S.

    2017-02-01

    A multi-beam beacon was transmitted from the Optical Communication Telescope Laboratory (OCTL) located at Table Mountain, CA to the Lunar Laser Space Terminal (LLST), on-board the Lunar Atmospheric Dust and Environment Explorer (LADEE) spacecraft, during NASA's recent Lunar Laser Communication Demonstration (LLCD). The laser beacon (1568+/-0.1 nm) was square wave modulated and sensed by a quadrant sensor on LLST. While link acquisition and tracking proceeded with the sensed signal, on-board processing extracted power incident on the quadrant sensor and telemetered it down over the optical downlink. Subsequently, post-processing of the codewords received at OCTL retrieved the power time series recorded at LLST. Analysis comparing measured and predicted mean irradiance delivered to LLST consistently agreed to within < 1 decibel (dB). Irradiance fluctuations detected at LLST were reconciled with an uplink wave-propagation simulation model using Kolmogorov phase screens.

  1. Optical recording in functional polymer nanocomposites by multi-beam interference holography

    Science.gov (United States)

    Zhuk, Dmitrij; Burunkova, Julia; Kalabin, Viacheslav; Csarnovics, Istvan; Kokenyesi, Sandor

    2017-05-01

    Our investigations relate to the development of new polymer nanocomposite materials and technologies for fabrication of photonic elements like gratings, integrated elements, photonic crystals. The goal of the present work was the development and application of the multi-beam interference method for one step, direct formation of 1-, 2- or even 3D photonic structures in functional acrylate nanocomposites, which contain SiO2 and Au nanoparticles and which are sensitized to blue and green laser illumination. The presence of gold nanoparticles and possibility to excite plasmonic effects can essentially influence the polymerization processes and the spatial redistribution of nanoparticles in the nanocomposite during the recording. This way surface and volume phase reliefs can be recorded. It is essential, that no additional treatments of the material after the recording are necessary and the elements possess high transparency, are stable after some relaxation time. New functionalities can be provided to the recorded structures if luminescent materials are added to such materials.

  2. GOLD MINERAL PROSPECTING USING PHASED ARRAY TYPE L-BAND SYNTHETIC APERTURE RADAR (PALSAR SATELLITE REMOTE SENSING DATA, CENTRAL GOLD BELT, MALAYSIA

    Directory of Open Access Journals (Sweden)

    A. Beiranvand Pour

    2016-06-01

    Full Text Available The Bentong-Raub Suture Zone (BRSZ of Peninsular Malaysia is one of the significant structural zones in Sundaland, Southeast Asia. It forms the boundary between the Gondwana-derived Sibumasu terrane in the west and Sukhothai arc in the east. The BRSZ is also genetically related to the sediment-hosted/orogenic gold deposits associated with the major lineaments and form-lines in the central gold belt Central Gold Belt of Peninsular Malaysia. In tropical environments, heavy tropical rainforest and intense weathering makes it impossible to map geological structures over long distances. Advances in remote sensing technology allow the application of Synthetic Aperture Radar (SAR data in geological structural analysis for tropical environments. In this investigation, the Phased Array type L-band Synthetic Aperture Radar (PALSAR satellite remote sensing data were used to analyse major geological structures in Peninsular Malaysia and provide detailed characterization of lineaments and form-lines in the BRSZ, as well as its implication for sediment-hosted/orogenic gold exploration in tropical environments. The major geological structure directions of the BRSZ are N-S, NNE-SSW, NE-SW and NW-SE, which derived from directional filtering analysis to PALSAR data. The pervasive array of N-S faults in the study area and surrounding terrain is mainly linked to the N-S trending of the Suture Zone. N-S striking lineaments are often cut by younger NE-SW and NW-SE-trending lineaments. Gold mineralized trends lineaments are associated with the intersection of N-S, NE-SW, NNW-SSE and ESE-WNW faults and curvilinear features in shearing and alteration zones. Lineament analysis on PALSAR satellite remote sensing data is a useful tool for detecting the boundary between the Gondwana-derived terranes and major geological features associated with suture zone especially for large inaccessible regions in tropical environments.

  3. The data management of a phase III efficacy trial of an 11-valent pneumococcal conjugate vaccine and related satellite studies conducted in the Philippines

    Directory of Open Access Journals (Sweden)

    Sanvictores Diozele Hazel M

    2012-06-01

    Full Text Available Abstract Background A large phase III placebo-controlled, randomized efficacy trial of an investigational 11-valent pneumococcal conjugate vaccine against pneumonia in children less than 2 years of age was conducted in the Philippines from July 2000 to December 2004. Clinical data from 12,194 children who were given either study vaccine or placebo was collected from birth up to two years of age for the occurrence of radiologically proven pneumonia as the primary endpoint, and for clinical pneumonia and invasive pneumococcal disease as the secondary endpoints. Several tertiary endpoints were also explored. Along the core trial, several satellite studies on herd immunity, cost-effectiveness of the study vaccine, acute otitis media, and wheezing were conducted. Results We describe here in detail how the relevant clinical records were managed and how quality control procedures were implemented to ensure that valid data were obtained respectively for the core trial and for the satellite studies. We discuss how the task was achieved, what the challenges were and what might have been done differently. Conclusions There were several factors that made the task of data management doable and efficient. First, a pre-trial data management system was available. Secondly, local committed statisticians, programmers and support staff were available and partly familiar to clinical trials. Thirdly, the personnel had undergone training during trial and grew with the task they were supposed to do. Thus the knowledge needed to develop and operate clinical data system was fully transferred to local staff. Trial registration Current Controlled Trials ISRCTN62323832

  4. Development of Method in Precise Multibeam Acoustic Bathymetry

    Institute of Scientific and Technical Information of China (English)

    ZHAO Jianhu; LIU Jiugnan

    2003-01-01

    The sound ray tracing method can achieve higher accuracy in determining depths and plan positions with multibeam echo sounding system. In data processing, actual sound speed profile must be used in the method. However, the method is too complicated. In order to overcome the shortcoming, this paper presents a new method, the position correction method. Two situations are considered in the new method, namely, change of sound velocity keeps constant gradient in whole water column (including N layers) or in different water layer.

  5. A new integrated slot element feed array for multibeam systems

    Science.gov (United States)

    Yngvesson, K. Sigfrid; Johansson, Joakim F.; Kollberg, Erik L.

    1986-01-01

    A feed array consisting of constant width slot antennas (CWSA), fed from a block containing fin-line transitions, has been developed. The array has a two-dimensional configuration, with five elements each on five parallel substrates. Beamwidths are compatible with use in f/D = 1.0 multibeam systems, with optimum taper. Array element spacings are close to a factor of two smaller than for other typical arrays, and spillover efficiency is about 65 percent.

  6. Theoretical analysis of a parabolic torus reflector antenna with multibeam

    Institute of Scientific and Technical Information of China (English)

    杜彪; 杨可忠; 钟顺时

    1995-01-01

    The parametric equations and the formulas of unit normal vector and surface element for aparabolic torus reflector antenna are derived and the mechanism of producing multibeam is proposed, Based on physical optics, the radiation pattern formulas for the antenna are given, with which the effects of geometric parameters on the antenna are studied. The good agreement between the calculated patterns and the measured ones shows that the theory is helpful for designing parabolic torus antennas.

  7. Multibeam 3D Underwater SLAM with Probabilistic Registration

    Directory of Open Access Journals (Sweden)

    Albert Palomer

    2016-04-01

    Full Text Available This paper describes a pose-based underwater 3D Simultaneous Localization and Mapping (SLAM using a multibeam echosounder to produce high consistency underwater maps. The proposed algorithm compounds swath profiles of the seafloor with dead reckoning localization to build surface patches (i.e., point clouds. An Iterative Closest Point (ICP with a probabilistic implementation is then used to register the point clouds, taking into account their uncertainties. The registration process is divided in two steps: (1 point-to-point association for coarse registration and (2 point-to-plane association for fine registration. The point clouds of the surfaces to be registered are sub-sampled in order to decrease both the computation time and also the potential of falling into local minima during the registration. In addition, a heuristic is used to decrease the complexity of the association step of the ICP from O ( n 2 to O ( n . The performance of the SLAM framework is tested using two real world datasets: First, a 2.5D bathymetric dataset obtained with the usual down-looking multibeam sonar configuration, and second, a full 3D underwater dataset acquired with a multibeam sonar mounted on a pan and tilt unit.

  8. Meter Accuracy Seafloor Geodesy using Repeated Multibeam Surveys

    Science.gov (United States)

    DeSanto, J. B.; Sandwell, D. T.

    2014-12-01

    Ship-board multibeam surveys are a useful tool in measuring tectonic deformation of the seafloor, having been used to measure the ~50 m of surface slip along the Japan trench during the 2011 Tohoku-Oki earthquake with an uncertainty of 20 m (Fujiwara et al, 2011, Science). In this study, we investigate the improvement in positioning accuracy obtainable when comparing multibeam and sidescan surveys repeated along the same track to within 1/10 of the critical baseline and taken at a slow ship speed of 1 knot. We compare two surveys of the Juan de Fuca Ridge axis fitting these criteria with two coincident surveys of the Cocos Ridge, taken at 11 knots. Both pairs of surveys were collected using a Simrad EM120 sonar system aboard the RV Roger Revelle. We find the multibeam surveys of the Juan de Fuca ridge axis sufficient to measure displacements accurate to better than 2 m, a marked improvement over the 50 m accuracy of the Cocos ridge surveys. Likewise, we can measure displacement accurate to 2 m using the sidescan data from the Juan de Fuca surveys. This accuracy is sufficient to observe meter-level horizontal movements on the deep ocean associated with large earthquakes and landslides.

  9. Tests of Multibeam Scintillation Mitigation on Laser Uplinks

    Science.gov (United States)

    Wilson, Keith

    2004-01-01

    A report presents additional details about parts of the program of research and development that is the topic of the immediately preceding article. The report emphasizes those aspects of the program that pertain to the use of multiple uplink laser beams in a ground-to-spacecraft optical communication system to reduce (relative to the case of a single uplink laser beam) the depth and frequency of occurrence of fades in the uplink signal received at the spacecraft. The underlying multibeam scintillation-mitigation concept was described in "Multiple-Beam Transmission for Optical Communication" (NPO-20384), NASA Tech Briefs, Vol. 22, No. 11 (November 1998), page 56. The report discusses the need for mitigating uplink scintillation; briefly describes the Optical Communications Telescope Laboratory and its role as the ground station in the research; summarizes prior experiments in uplink scintillation and multibeam mitigation of scintillation in ground-to-spacecraft laser communications; and describes key experiments planned to be performed in the next five years. The report then elaborates somewhat on the initial experiments, which are to be dedicated to understanding and perfecting the multibeam scintillation-mitigation strategy.

  10. Vibration piezoelectric energy harvester with multi-beam

    Directory of Open Access Journals (Sweden)

    Yan Cui

    2015-04-01

    Full Text Available This work presents a novel vibration piezoelectric energy harvester, which is a micro piezoelectric cantilever with multi-beam. The characteristics of the PZT (Pb(Zr0.53Ti0.47O3 thin film were measured; XRD (X-ray diffraction pattern and AFM (Atomic Force Microscope image of the PZT thin film were measured, and show that the PZT (Pb(Zr0.53Ti0.47O3 thin film is highly (110 crystal oriented; the leakage current is maintained in nA magnitude, the residual polarisation Pr is 37.037 μC/cm2, the coercive field voltage Ec is 27.083 kV/cm, and the piezoelectric constant d33 is 28 pC/N. In order to test the dynamic performance of the energy harvester, a new measuring system was set up. The maximum output voltage of the single beam of the multi-beam can achieve 80.78 mV under an acceleration of 1 g at 260 Hz of frequency; the maximum output voltage of the single beam of the multi-beam is almost 20 mV at 1400 Hz frequency.

  11. Multibeam 3D Underwater SLAM with Probabilistic Registration.

    Science.gov (United States)

    Palomer, Albert; Ridao, Pere; Ribas, David

    2016-04-20

    This paper describes a pose-based underwater 3D Simultaneous Localization and Mapping (SLAM) using a multibeam echosounder to produce high consistency underwater maps. The proposed algorithm compounds swath profiles of the seafloor with dead reckoning localization to build surface patches (i.e., point clouds). An Iterative Closest Point (ICP) with a probabilistic implementation is then used to register the point clouds, taking into account their uncertainties. The registration process is divided in two steps: (1) point-to-point association for coarse registration and (2) point-to-plane association for fine registration. The point clouds of the surfaces to be registered are sub-sampled in order to decrease both the computation time and also the potential of falling into local minima during the registration. In addition, a heuristic is used to decrease the complexity of the association step of the ICP from O(n2) to O(n) . The performance of the SLAM framework is tested using two real world datasets: First, a 2.5D bathymetric dataset obtained with the usual down-looking multibeam sonar configuration, and second, a full 3D underwater dataset acquired with a multibeam sonar mounted on a pan and tilt unit.

  12. Vibration piezoelectric energy harvester with multi-beam

    Energy Technology Data Exchange (ETDEWEB)

    Cui, Yan, E-mail: yanc@dlut.edu.cn; Zhang, Qunying, E-mail: zhangqunying89@126.com; Yao, Minglei, E-mail: yaomingleiok@126.com [Key Laboratory for Precision and Non-traditional Machining Technology of the Ministry of Education, Dalian University of Technology, 116024, Dalian, Liaoning Province (China); Dong, Weijie, E-mail: dongwj@dlut.edu.cn [School of Electronic and Information Engineering, Dalian University of Technology, 116024, Dalian, Liaoning Province (China); Gao, Shiqiao, E-mail: gaoshq@bit.edu.cn [State Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology, 100081, Beijing Province (China)

    2015-04-15

    This work presents a novel vibration piezoelectric energy harvester, which is a micro piezoelectric cantilever with multi-beam. The characteristics of the PZT (Pb(Zr{sub 0.53}Ti{sub 0.47})O{sub 3}) thin film were measured; XRD (X-ray diffraction) pattern and AFM (Atomic Force Microscope) image of the PZT thin film were measured, and show that the PZT (Pb(Zr{sub 0.53}Ti{sub 0.47})O{sub 3}) thin film is highly (110) crystal oriented; the leakage current is maintained in nA magnitude, the residual polarisation Pr is 37.037 μC/cm{sup 2}, the coercive field voltage Ec is 27.083 kV/cm, and the piezoelectric constant d{sub 33} is 28 pC/N. In order to test the dynamic performance of the energy harvester, a new measuring system was set up. The maximum output voltage of the single beam of the multi-beam can achieve 80.78 mV under an acceleration of 1 g at 260 Hz of frequency; the maximum output voltage of the single beam of the multi-beam is almost 20 mV at 1400 Hz frequency. .

  13. The Curious Case of Palomar 13: The Influence of the Orbital Phase on the Appearance of Galactic Satellites

    CERN Document Server

    Kuepper, A H W; Kroupa, P

    2010-01-01

    We investigate the dynamical status of the low-mass globular cluster Palomar 13 by means of N-body computations to test whether its unusually high mass-to-light ratio of about 40 and its peculiarly shallow surface density profile can be caused by tidal shocking. Alternatively, we test - by varying the assumed proper motion - if the orbital phase of Palomar 13 within its orbit about the Milky Way can influence its appearance and thus may be the origin of these peculiarities, as has been suggested by Kuepper et al. (2010). We find that, of these two scenarios, only the latter can explain the observed mass-to-light ratio and surface density profile. We note, however, that the particular orbit that best reproduces those observed parameters has a proper motion inconsistent with the available literature value. We discuss this discrepancy and suggest that it may be caused by an underestimation of the observational uncertainties in the proper motion determination. We demonstrate that Palomar 13 is most likely near ap...

  14. Interpolation of Reconnaissance Multibeam Bathymetry From North-Central Long Island Sound

    Science.gov (United States)

    Poppe, L. J.; Ackerman, S. D.; Doran, E. F.; Beaver, A. J.; Crocker, J. M.; Schattgen, T.

    2006-12-01

    The USGS, in cooperation with NOAA and the CT-DEP, is producing detailed maps of the sea floor in Long Island Sound. As part of the current phase of this cooperative research program, which is directed toward studies of sea-floor topography and its effect on the distributions of sedimentary environments and benthic habitats, we interpolated and regridded the reconnaissance multibeam echosounder (MBES) data from three Basic Hydrographic Surveys into complete-coverage data sets and images of the Sound's sea floor. Within the context of sea-floor mapping, the word "reconnaissance" typically refers to geophysical surveys with ship- track spacing too great to acquire 100% coverage of the seabed. Although this approach resulted in original multibeam bathymetric data sets that had narrow stripes of no data between the ship's tracks, it met the hydrographic standards of accuracy and was acceptable for charting applications because 100% acoustic coverage was achieved with concurrently collected sidescan sonar. The original reconnaissance grids for surveys H11043, H11044, and H11045 had resolutions of 1 m, 1.5 m, and 5 m, respectively; areas of no data within these surveys comprised approximately 30%, 10%, and 45%, respectively. After interpolation, the data from survey H11043 was regridded to 2 m; surveys H11044 and H11045 were both regridded to 5 m. The interpolated bathymetric data sets, covering approximately 524 km2, provide a more-continuous perspective of the sea floor that helps define topographic variability, a primary control of benthic habitat diversity, and improve our understanding of oceanographic processes controlling the distribution of sediments and benthic habitats. Inasmuch as precise information on environmental setting is important for selecting sampling sites and accurately interpreting point measurements, these data sets can also serve as base maps for subsequent sedimentological, geochemical, and biological research.

  15. The start-up phase of the national satellite forest monitoring systems for DRC and PNG: a joint venture between FAO and INPE

    Science.gov (United States)

    Jonckheere, I. G.; FAO UN-REDD Team Forestry Department

    2011-12-01

    Reducing Emissions from Deforestation and Forest Degradation (REDD) is an effort to create a financial value for the carbon stored in forests, offering incentives for developing countries to reduce emissions from forested lands and invest in low-carbon paths to sustainable development. "REDD+" goes beyond deforestation and forest degradation, and includes the role of conservation, sustainable management of forests and enhancement of forest carbon stocks. In the framework of getting countries ready for REDD+, the UN-REDD Programme, a partnership between UNEP, FAO and UNDP, assists developing countries to prepare and implement national REDD+ strategies. Designed collaboratively by a broad range of stakeholders, national UN-REDD Programmes are informed by the technical expertise of FAO, UNDP and UNEP. For the monitoring, reporting and verification, FAO supports the countries to develop satellite forest monitoring systems that allow for credible measurement, reporting and verification (MRV)of REDD+ activities. These are among the most critical elements for the successful implementation of any REDD+ mechanism, also following the COP 16 decisions in Cancun last year. The UN-REDD Programme through a joint effort of FAO and Brazil's National Space Agency, INPE, is supporting countries to develop cost-effective, robust and compatible national monitoring and MRV systems, providing tools, methodologies, training and knowledge sharing that help countries to strengthen their technical and institutional capacity for effective MRV systems. To develop strong nationally-owned forest monitoring systems, technical and institutional capacity building is key. The UN-REDD Programme, through FAO, has taken on intensive training together with INPE, and has provided technical help and assistance for in-country training and implementation for national satellite forest monitoring. The goal of the start-up phase for DRC and Papua New Guinea (PNG) in this capacity building effort is the

  16. Satellite RNAs and Satellite Viruses.

    Science.gov (United States)

    Palukaitis, Peter

    2016-03-01

    Satellite RNAs and satellite viruses are extraviral components that can affect either the pathogenicity, the accumulation, or both of their associated viruses while themselves being dependent on the associated viruses as helper viruses for their infection. Most of these satellite RNAs are noncoding RNAs, and in many cases, have been shown to alter the interaction of their helper viruses with their hosts. In only a few cases have the functions of these satellite RNAs in such interactions been studied in detail. In particular, work on the satellite RNAs of Cucumber mosaic virus and Turnip crinkle virus have provided novel insights into RNAs functioning as noncoding RNAs. These effects are described and potential roles for satellite RNAs in the processes involved in symptom intensification or attenuation are discussed. In most cases, models describing these roles involve some aspect of RNA silencing or its suppression, either directly or indirectly involving the particular satellite RNA.

  17. Multibeam bathymetry and CTD measurements in two fjord systems in southeastern Greenland

    Directory of Open Access Journals (Sweden)

    K. K. Kjeldsen

    2017-08-01

    Full Text Available We present bathymetry and hydrological observations collected in the summer of 2014 from two fjord systems in southeastern Greenland with a multibeam sonar system. Our results provide a detailed bathymetric map of the fjord complex around the island of Skjoldungen in Skjoldungen Fjord and the outer part of Timmiarmiut Fjord and show far greater depths compared to the International Bathymetric Chart of the Arctic Ocean. The hydrography collected shows different properties in the fjords with the bottom water masses below 240 m in Timmiarmiut Fjord being 1–2 °C warmer than in the two fjords around Skjoldungen, but data also illustrate the influence of sills on the exchange of deeper water masses within fjords. Moreover, evidence of subglacial discharge in Timmiarmiut Fjord, which is consistent with satellite observations of ice mélange set into motion, adds to our increasing understanding of the distribution of subglacial meltwater. Data are available through the PANGAEA website at https://doi.pangaea.de/10.1594/PANGAEA.860627.

  18. Multibeam bathymetry and CTD measurements in two fjord systems in southeastern Greenland

    Science.gov (United States)

    Kjellerup Kjeldsen, Kristian; Weinrebe, Reimer Wilhelm; Bendtsen, Jørgen; Anker Bjørk, Anders; Kjær, Kurt Henrik

    2017-08-01

    We present bathymetry and hydrological observations collected in the summer of 2014 from two fjord systems in southeastern Greenland with a multibeam sonar system. Our results provide a detailed bathymetric map of the fjord complex around the island of Skjoldungen in Skjoldungen Fjord and the outer part of Timmiarmiut Fjord and show far greater depths compared to the International Bathymetric Chart of the Arctic Ocean. The hydrography collected shows different properties in the fjords with the bottom water masses below 240 m in Timmiarmiut Fjord being 1-2 °C warmer than in the two fjords around Skjoldungen, but data also illustrate the influence of sills on the exchange of deeper water masses within fjords. Moreover, evidence of subglacial discharge in Timmiarmiut Fjord, which is consistent with satellite observations of ice mélange set into motion, adds to our increasing understanding of the distribution of subglacial meltwater. Data are available through the PANGAEA website at https://doi.pangaea.de/10.1594/PANGAEA.860627.

  19. The technical consideration of multi-beam mask writer for production

    Science.gov (United States)

    Lee, Sang Hee; Ahn, Byung-Sup; Choi, Jin; Shin, In Kyun; Tamamushi, Shuichi; Jeon, Chan-Uk

    2016-10-01

    Multi-beam mask writer is under development to solve the throughput and patterning resolution problems in VSB mask writer. Theoretically, the writing time is appropriate for future design node and the resolution is improved with multi-beam mask writer. Many previous studies show the feasible results of resolution, CD control and registration. Although such technical results of development tool seem to be enough for mass production, there are still many unexpected problems for real mass production. In this report, the technical challenges of multi-beam mask writer are discussed in terms of production and application. The problems and issues are defined based on the performance of current development tool compared with the requirements of mask quality. Using the simulation and experiment, we analyze the specific characteristics of electron beam in multi-beam mask writer scheme. Consequently, we suggest necessary specifications for mass production with multi-beam mask writer in the future.

  20. Multibeam collection for RC2511: Multibeam data collected aboard Robert Conrad from 1984-09-13 to 1984-10-14, departing from Bermuda and returning to Bermuda

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  1. Multibeam collection for BELL02: Multibeam data collected aboard unknown from Unknown Date to Unknown Date, departing from Unknown Port and returning to Unknown Port

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  2. Multibeam collection for BELL01: Multibeam data collected aboard unknown from Unknown Date to Unknown Date, departing from Unknown Port and returning to Unknown Port

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  3. Multibeam collection for EW0202: Multibeam data collected aboard Maurice Ewing from 2002-02-24 to 2002-03-26, departing from Guam and returning to Guam

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  4. Multibeam collection for EW0203: Multibeam data collected aboard Maurice Ewing from 2002-03-28 to 2002-04-25, departing from Guam and returning to Guam

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  5. Multibeam collection for GEOMETEP: Multibeam data collected aboard Sonne from 1985-12-17 to 1986-01-07, departing from Unknown Port and returning to Unknown Port

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  6. Centriolar satellites

    DEFF Research Database (Denmark)

    Tollenaere, Maxim A X; Mailand, Niels; Bekker-Jensen, Simon

    2015-01-01

    Centriolar satellites are small, microscopically visible granules that cluster around centrosomes. These structures, which contain numerous proteins directly involved in centrosome maintenance, ciliogenesis, and neurogenesis, have traditionally been viewed as vehicles for protein trafficking...... highlight newly discovered regulatory mechanisms targeting centriolar satellites and their functional status, and we discuss how defects in centriolar satellite components are intimately linked to a wide spectrum of human diseases....

  7. 箭载共形相控阵卫星数据链通信仿真研究%The communication simulation of data link between satellite and rocket-borne conformal phased array

    Institute of Scientific and Technical Information of China (English)

    曾国奇; 李思吟; 韦志棉; 饶赣新

    2012-01-01

    Using the relay satellite as a communications relay, the rocket and the relay satellite are within mutual sight during the whole launch of the launch vehicle. Without any shelter, uninterrupted measurement and control can be achieved on the launch vehicle. In this paper, the transmission losses of the data link between satellite and rocket-borne conformal phased array satellite were analyzed, such as free-space attenuation, atmospheric attenuation, flame attenuation, polarization decay, antenna pointing error loss, and attenuation induced by rain. And the safety margin of the data link between satellite and rocket-borne conformal phased array satellite is simulated during the rocket flight in the S-band.%利用中继星作为通信中继,在运载火箭发射的全程中火箭与中继星都视线可见,不存在遮挡,可以实现对运载火箭的不间断测控.文章对运载火箭共形相控阵卫星数据链传输过程中的自由空间衰减、大气衰减、火焰衰减、极化衰减、天线指向误差损耗、雨衰等进行了分析,并对火箭飞行过程中,S波段箭载共形相控阵卫星数据链的安全裕度进行了仿真.

  8. Satellite theory

    Science.gov (United States)

    Kozai, Y.

    1981-04-01

    The dynamical characteristics of the natural satellite of Mars, Jupiter, Saturn, Uranus and Neptune are analyzed on the basis of the solar tidal perturbation factor and the oblateness factor of the primary planet for each satellite. For the inner satellites, for which the value of the solar tidal factor is much smaller than the planetary oblateness factor, it is shown that the eccentricity and inclination of satellite orbits are generally very small and almost constant; several pairs of inner satellites are also found to exhibit commensurable mean motions, or secular accelerations in mean longitude. In the case of the outer satellites, for which solar perturbations are dominant, secular perturbations and long-period perturbations may be derived by the solution of equations of motion reduced to one degree of freedom. The existence of a few satellites, termed intermediary satellites, for which the solar tidal perturbation is on the order of the planetary oblateness factor, is also observed, and the pole of the orbital plane of the satellite is noted to execute a complex motion around the pole of the planet or the orbital plane of the planet.

  9. Satellite Photometric Error Determination

    Science.gov (United States)

    2015-10-18

    of nearly specular reflections from most solar panels. Our primary purpose in presenting these two plots is to demonstrate the usefulness of...than a transformation for stars because the spectral energy distribution of satellites can change with phase angle and is subject to specular

  10. 卫星常用调相信号自动调制识别算法%Automatic recognition for the satellite phase modulated signals

    Institute of Scientific and Technical Information of China (English)

    裴立业; 江桦

    2013-01-01

    针对高阶幅度相移键控(APSK)信号在卫星通信中的应用,提出了一种识别数字调相信号的新方法。在信噪比估计的基础上,利用信号包络的统计特征对 MPSK,MQAM,16APSK 和32APSK信号进行区分。理论推导和实验仿真验证了该统计特征具有对加性高斯白噪声和滚降系数不敏感的特性。根据鲁棒性较好的四阶循环累积量提出一种新的特征参数Q以实现MPSK和MQAM信号的类内识别。仿真表明,当信噪比达到5 dB时,该方法拥有较好的识别率(>95%)。%A new algorithm for automatic classification of digital phase modulated signals is proposed aiming for the application of high-order Amplitude Phase Shift Keying(APSK) signals in satellite communication. The algorithm utilizes signal envelope statistical feature to distinguish MPSK, MQAM, 16APSK and 32APSK based on the SNR estimation. Nevertheless, it is proved that this statistical feature parameter is insensitive to additive Gaussian noise and the roll-off factor of the pulse shaping filter by theoretical deduction and simulation experiments. Therefore a new statistical parameter Q is proposed according to four-order cyclic cumulant which is robust to the presence of carrier frequency offsets, time delay and phase offsets. {QPSK 8PSK} and {16QAM 32QAM} can be classified based on the parameter Q. Simulation results show that the proposed recognition algorithm can obtain high probability of correct identification(>95%) when the SNR is above 5 dB.

  11. Interferometric source of multi-color, multi-beam entangled photons with mirror and mixer

    Science.gov (United States)

    Dress, William B.; Kisner, Roger A.; Richards, Roger K.

    2004-06-01

    53 Systems and methods are described for an interferometric source of multi-color, multi-beam entangled photons. An apparatus includes: a multi-refringent device optically coupled to a source of coherent energy, the multi-refringent device providing a beam of multi-color entangled photons; a condenser device optically coupled to the multi-refringent device, the condenser device i) including a mirror and a mixer and ii) converging two spatially resolved portions of the beam of multi-color entangled photons into a converged multi-color entangled photon beam; a tunable phase adjuster optically coupled to the condenser device, the tunable phase adjuster changing a phase of at least a portion of the converged multi-color entangled photon beam to generate a first interferometeric multi-color entangled photon beam; and a beam splitter optically coupled to the condenser device, the beam splitter combining the first interferometeric multi-color entangled photon beam with a second interferometric multi-color entangled photon beam.

  12. Evaluation of the Capability of a Multibeam Confocal Inspection System for Inspection of EUVL Mask Blanks

    Science.gov (United States)

    Stivers, Alan R.; Liang, Ted; Penn, Michael J.; Lieberman, Barry; Shelden, Gilbert V.; Folta, James A.; Larson, Cindy C.; Mirkarimi, Paul B.; Walton, Christopher C.; Gulliksong, Eric M.; Yi, Moonsuk

    2002-12-01

    Extreme ultraviolet (EUV) multilayer defects (phase defects) are a defect type unique to extreme ultraviolet lithography (EUVL) masks. A manufacturable inspection capability for these defects is key to the success of EUV lithography. Simulations of EUV scattering from multilayer defects suggest that defect printability is related to the phase error induced by the defect, which is in turn strongly coupled to the size of a multilayer surface protrusion or intrusion. We can adopt a strategy of measuring the multilayer surface to detect phase defects. During the past year a working group composed of members of Intel Corporation, Lawrence Berkeley and Lawrence Livermore National Laboratories, and International Sematech searched for a commercial tool for EUVL mask substrate and blank inspection. This working group established the tool requirements, methodologies for tool evaluation, collected data and recommended a supplier for further development with International Sematech. We collected data from several vendors and found that a multibeam confocal inspection (MCI) system had a capability significantly better than the tools used today. We will present our strategy, requirements, methodologies and results. We will discuss in detail our unique programmed substrate and multilayer defect masks used to support the tool selection, including their actinic characterization. We will present data that quantifies the inspection capability of the MCI system.

  13. Multibeam bathymetry and selected perspective views offshore San Diego, California

    Science.gov (United States)

    Dartnell, Peter; Normark, William R.; Driscoll, Neal W.; Babcock, Jeffrey M.; Gardner, James V.; Kvitek, Rikk G.; Iampietro, Pat J.

    2007-01-01

    This set of two posters consists of a map on one sheet and a set of seven perspective views on the other. The ocean floor image was generated from multibeam-bathymetry data acquired by Federal and local agencies as well as academic institutions including: - U.S. Geological Survey mapped from the La Jolla Canyon south to the US-Mexico border using a Kongsberg Simrad multibeam echosounder system (MBES) (March - April 1998). Data and metadata available at http://pubs.usgs.gov/of/2004/1221/. - Woods Hole Oceanographic Institution and SCRIPPS Institution of Oceanography mapped the majority of the La Jolla Fan Valley including the sea floor to the north and south of the valley using a Seabeam 2100 MBES. Data available at http://www.ngdc.noaa.gov/mgg/bathymetry/multibeam.html. Survey ID, AT07L09, Chief Scientists, Barrie Walden and Joseph Coburn (April 2002). - California State University, Monterey Bay, mapped Scripps Canyon and the head of La Jolla Canyon using a Reson 8101 MBES (October 2001). Data and metadata available at http://seafloor.csumb.edu/SFMLwebDATA.htm. This work was funded by the California Department of Fish and Game California Coastal Conservancy, San Diego Association of Governments (SANDAG), California Department of Fish and Game, and Fugro Pelagos mapped the nearshore region out to about 35-40 m. - The sea floor within this image that has not been mapped with MBES is filled in with interpreted bathymetry gridded from single-beam data available at http://www.ngdc.noaa.gov/mgg/bathymetry/hydro.html. Depths are in meters below sea level, which is referenced to Mean Lower Low Water.

  14. The Use of Satellite Imagery in the Monitoring and Forecasting of Sargassum Seaweed in the Caribbean Phase II of the Sargassum Early Advisory System

    Science.gov (United States)

    Frazier, J.; Webster, R.; Linton, T.; Hill, B. N.

    2013-12-01

    In 2011, the Southern Caribbean was plagued by an unusually massive amount of seaweed wrack, an event so rare that locals couldn't think of a season where Sargassum had been that abundant, for sixty years. At this time, the SEAS program had been created, however the path of the seaweed from the Atlantic to the beaches of Texas had yet to be determined. This event sparked the idea that seaweed migrated through the Caribbean then North through the Yucatan Peninsula. While this idea was only partially correct, it did initiate the second phase of the SEAS Program. As it turns out, the seaweed drifts through the Northern passages of the Caribbean (Windward, Mona, and Anegada Passages) and migrates westward, rather than entering the Caribbean from the Southeastern islands (the Virgin Islands down to Granada). Monitoring these passes using ground-truthing and local reports has proven difficult, so in order to determine the presence of seaweed, one can use remote sensing. NASA's satellite Landsat 7 produces images of the passes every eight days, allowing the SEAS Team to monitor the Sargassum. These images have a sufficient resolution to see seaweed mats in the ocean. Based on several factors, such as ocean and wind currents, time of the year, and size of seaweed mats, one can ultimately forecast Sargassum as it makes its journey through the loop system. The seaweed is monitored as it migrates westward, and eventually gets pushed North in massive blooms as a result of neritic waters. These blooms can travel North in warm water gyres. The Sargassum can then break off and wash up on the beaches of Texas or get caught in the Gulf Stream where it is flushed out the Florida Straits back into the Atlantic. Remote sensing makes the first ever system of monitoring Sargassum possible and allows for advanced warning of these troublesome seaweed wracks up and down the coast.

  15. Echoview as a multibeam sonar data processing and analysis toolkit for fisheries research

    Science.gov (United States)

    Buelens, Bart; Pauly, Tim; Higginbottom, Ian

    2003-10-01

    Echoview is a hydroacoustic data analysis software package, widely used in the fisheries research and stock assessment communities. Originally developed to handle a variety of single-beam sonar data formats, Echoview has been extended to support multibeam data. Multibeam data logging, lossless compression, and real time beamforming and display are some of the software's core features. Multibeam data has an additional dimension compared to single-beam data, and a 3D data viewer has been developed providing 3D visualizations of the seabed and fish schools detected by built-in algorithms. Since the multibeam module is just one of many software modules of the Echoview package, data from other sources such as single-beam sonar systems and current profilers can be combined and analyzed together with the multibeam data. The combination of coincident fish density estimates from calibrated single-beam backscatter data with school volume estimates from multibeam data will represent a significant improvement in stock assessment methods. Ongoing research and development will make it possible for Echoview to follow and even set new trends in multibeam water-column data analysis for fisheries research. Features under development include calibration, vessel motion compensation, improved feature detection, and enhanced and animated 3D displays.

  16. Challenges and technical requirements for multi-beam mask writer development

    Science.gov (United States)

    Lee, Sang Hee; Choi, Jin; Lee, Ho June; Shin, In Kyun; Tamamushi, Shuichi; Jeon, Chan-Uk

    2014-07-01

    Because mask patterning quality of CD uniformity, MTT, registration and smaller assist feature size is important for wafer patterning, the higher exposure dose and complex pattern design will be necessary. It is the reason why the faster and more accurate e-beam mask writer is needed for future design node. Multi-beam mask writer is the most promising new e-beam mask writer technology for future sub-10nm device mask patterning to solve the pattern quality issue and writing time problem. In this report, the technical challenges of multi-beam mask writer are discussed by comparison with problems of current VSB e-beam mask writer. Comparing with e-beam mask writer which has the critical issues of beam size and position control, the application of entirely different methods and techniques of CD and position control is essential for multi-beam mask writer which has new architecture and writing strategy. Using the simulation method, we present the different challenges between VSB and multi-beam mask writer. And there are many important technical requirements to achieve expected specification of multi-beam mask writer. To understand such requirements, the patterning simulation and mathematical calculation are done for analysis. Based on the patterning simulation, the detail technical requirements and issues of multi-beam mask writer are achieved. Consequently, we suggest the direction of multi-beam mask writer development in terms of technical challenges and requirements.

  17. Design of a coil satellite centrifuge and its performance on counter-current chromatographic separation of 4-methylumbelliferyl sugar derivatives with polar organic-aqueous two-phase solvent systems.

    Science.gov (United States)

    Shinomiya, Kazufusa; Tokura, Koji; Kimura, Emiru; Takai, Midori; Harikai, Naoki; Yoshida, Kazunori; Yanagidaira, Kazuhiro; Ito, Yoichiro

    2015-05-01

    A new high-speed counter-current chromatograph, named coil satellite centrifuge (CSC), was designed and fabricated in our laboratory. The CSC apparatus produces the satellite motion such that the coiled column simultaneously rotates around the sun axis (the angular velocity, ω1), the planet axis (ω2) and the satellite axis (the central axis of the column) (ω3). In order to achieve this triplicate rotary motion without twisting of the flow tube, the rotation of each axis was determined by the following formula: ω1=ω2+ω3. This relation enabled to lay out the flow tube without twisting by the simultaneous rotation of three axes. The flow tube was introduced from the bottom side of the apparatus into the sun axis of the first rotary frame reaching the upper side of the planet axis and connected to the column in the satellite axis. The performance of the apparatus was examined on separation of 4-methylumbelliferyl (MU) sugar derivatives as test samples with organic-aqueous two-phase solvent systems composed of ethyl acetate/1-butanol/water (3:2:5, v/v) for lower phase mobile and (1:4:5, v/v) for upper phase mobile. With lower phase mobile, five 4-MU sugar derivatives including β-D-cellobioside (Cel), β-D-glucopyranoside, α-D-mannopyranoside, β-D-fucopyranoside and α-L-fucopyranoside (α-L-Fuc) were separated with the combined rotation around each axis at counterclockwise (CCW) (ω1) - CCW (ω2) - CCW (ω3) by the flow tube distribution. With upper phase mobile, three 4-MU sugar derivatives including α-L-Fuc, β-D-galactopyranoside and Cel were separated with the combined rotation around each axis at clockwise (CW) (ω1) - CW (ω2) - CW (ω3) by the flow tube distribution. A series of experiments on peak resolution and stationary phase retention revealed that better partition efficiencies were obtained at the flow rate of 0.5 mL/min (column 1) and 0.8 mL/min (column 2) for lower phase mobile and 0.2 mL/min (column 1) and 0.4 mL/min (column 2) for upper phase

  18. Correction for depth biases to shallow water multibeam bathymetric data

    Science.gov (United States)

    Yang, Fan-lin; Li, Jia-biao; Liu, Zhi-min; Han, Li-tao

    2013-04-01

    Vertical errors often present in multibeam swath bathymetric data. They are mainly sourced by sound refraction, internal wave disturbance, imperfect tide correction, transducer mounting, long period heave, static draft change, dynamic squat and dynamic motion residuals, etc. Although they can be partly removed or reduced by specific algorithms, the synthesized depth biases are unavoidable and sometimes have an important influence on high precise utilization of the final bathymetric data. In order to confidently identify the decimeter-level changes in seabed morphology by MBES, we must remove or weaken depth biases and improve the precision of multibeam bathymetry further. The fixed-interval profiles that are perpendicular to the vessel track are generated to adjust depth biases between swaths. We present a kind of postprocessing method to minimize the depth biases by the histogram of cumulative depth biases. The datum line in each profile can be obtained by the maximum value of histogram. The corrections of depth biases can be calculated according to the datum line. And then the quality of final bathymetry can be improved by the corrections. The method is verified by a field test.

  19. Correction for Depth Biases to Shallow Water Multibeam Bathymetric Data

    Institute of Scientific and Technical Information of China (English)

    YANG Fan-lin; LI Jia-biao; LIU Zhi-min; HAN Li-tao

    2013-01-01

    Vertical errors often present in multibeam swath bathymetric data.They are mainly sourced by sound refraction,internal wave disturbance,imperfect tide correction,transducer mounting,long period heave,static draft change,dynamic squat and dynamic motion residuals,etc.Although they can be partly removed or reduced by specific algorithms,the synthesized depth biases are unavoidable and sometimes have an important influence on high precise utilization of the final bathymetric data.In order to confidently identify the decimeter-level changes in seabed morphology by MBES,we must remove or weaken depth biases and improve the precision of multibeam bathymetry further.The fixed-interval profiles that are perpendicular to the vessel track are generated to adjust depth biases between swaths.We present a kind of postprocessing method to minimize the depth biases by the histogram of cumulative depth biases.The datum line in each profile can be obtained by the maximum value of histogram.The corrections of depth biases can be calculated according to the datum line.And then the quality of final bathymetry can be improved by the corrections.The method is verified by a field test.

  20. A new multibeam swath mapping echosounder for USCGC Healy

    Science.gov (United States)

    Chayes, D. N.; Roberts, S. D.; Perron, P. J.; Beaudoin, J.; Arko, R. A.; Perry, R. S.

    2010-12-01

    The Healy is the primary U.S. research icebreaker working in the Arctic. In 2003, the UNOLS Arctic Icebreaker Coordinating Committee (AICC) endorsed a plan to replace the aging SeaBeam 2112 multibeam echosounder that was purchased for the Healy at the beginning of construction and delivered with the vessel. Replacement was judged necessary due primarily to age and support issues associated with the original multibeam. Although the original plan was to do the replacement during the regularly scheduled drydock during CY 2006-07, the goal was realized during the CY 2009-10 drydock in Seattle, WA. The selected replacement was a Kongsberg EM122 with one degree (1°) transmit and two degree (2°) beam widths. The transducers are recessed behind windows to protect them from ice damage. The EM122 is configured with water column and raw stave data recording capabilities along with a synchronization interface. Due to the long cable runs and the potential for electromagnetic interference (EMI), a fiberoptic interface was implemented for this system. The installation was completed just prior to departure from the drydock in mid-March 2010, with integration into the existing data system largely completed prior to getting underway for engine trials. A successful Sea Acceptance Test was completed on June 12, 2010, just prior to the first of three research cruises in the Arctic during the 2010 season. Details of the installation and performance of the system will be presented.

  1. Method for enhancing stability in multi-beam microscopy

    Science.gov (United States)

    Huang, Yujia; Wang, Yifan; Kuang, Cuifang; Liu, Xu

    2016-10-01

    A method based on close loop control of four degrees of freedom (4DF) is proposed to enhance angular and translational stability of beams in multi-beam microscopy including STED, RESOLFT and CARS, etc. Deviations of multi-beams can be measured and corrected by our module, which is composed of four degrees of freedom position sensitive detectors (4DF PSD) and two actuator mirrors (AM) with motor and piezo servos. An output crosslink matrix obtained by a self-learning process is used to control four actuators to compensate for 4DF independently in beam deviations. We realize a standard deviation within about 2 µm at the entrance pupil plane (a spatial optical path of 180 cm for the whole system) using a compact stabilization system, which is equivalent to around 3 nm at the sample plane under the 100×  objective lens with a focal length of 2 mm, corresponding to an improvement of stability by an order of magnitude. Our method can react fast in real time and compensate for large disturbances caused by air agitation or temperature variation.

  2. W-CMOS blanking device for projection multibeam lithography

    Science.gov (United States)

    Jurisch, Michael; Irmscher, Mathias; Letzkus, Florian; Eder-Kapl, Stefan; Klein, Christof; Loeschner, Hans; Piller, Walter; Platzgummer, Elmar

    2010-05-01

    As the designs of future mask nodes become more and more complex the corresponding pattern writing times will rise significantly when using single beam writing tools. Projection multi-beam lithography [1] is one promising technology to enhance the throughput compared to state of the art VSB pattern generators. One key component of the projection multi-beam tool is an Aperture Plate System (APS) to form and switch thousands of individual beamlets. In our present setup a highly parallel beam is divided into 43,008 individual beamlets by a Siaperture- plate. These micrometer sized beams pass through larger openings in a blanking-plate and are individually switched on and off by applying a voltage to blanking-electrodes which are placed around the blanking-plate openings. A charged particle 200x reduction optics demagnifies the beamlet array to the substrate. The switched off beams are filtered out in the projection optics so that only the beams which are unaffected by the blanking-plate are projected to the substrate with 200x reduction. The blanking-plate is basically a CMOS device for handling the writing data. In our work the blanking-electrodes are fabricated using CMOS compatible add on processes like SiO2-etching or metal deposition and structuring. A new approach is the implementation of buried tungsten electrodes for beam blanking.

  3. Satellite Communications

    CERN Document Server

    Pelton, Joseph N

    2012-01-01

    The field of satellite communications represents the world's largest space industry. Those who are interested in space need to understand the fundamentals of satellite communications, its technology, operation, business, economic, and regulatory aspects. This book explains all this along with key insights into the field's future growth trends and current strategic challenges. Fundamentals of Satellite Communications is a concise book that gives all of the key facts and figures as well as a strategic view of where this dynamic industry is going. Author Joseph N. Pelton, PhD, former Dean of the International Space University and former Director of Strategic Policy at Intelstat, presents a r

  4. Mechanical scanner-less multi-beam confocal microscope with wavefront modulation

    Science.gov (United States)

    Takiguchi, Yu; Seo, Min-Woong; Kagawa, Keiichiro; Takamoto, Hisayoshi; Inoue, Takashi; Kawahito, Shoji; Terakawa, Susumu

    2016-04-01

    We propose a novel full-electronically controlled laser confocal microscope in which a liquid-crystal-on-silicon spatial light modulator and a custom CMOS imaging sensor are synchronized for performing multi-beam confocal imaging. Adaptive wavefront modulation for functional multi-beam excitation can be achieved by displaying appropriate computer generated holograms on the spatial light modulator, in consideration of the numerical aperture of the focusing objective. We also adopted a custom CMOS imaging sensor to realize multi-beam confocal microscopy without any physical pinhole. The confocality of this microscope was verified by improvements in transverse and axial resolutions of fluorescent micro-beads.

  5. Satellite Geomagnetism

    DEFF Research Database (Denmark)

    Olsen, Nils; Stolle, Claudia

    2012-01-01

    Observations of Earth’s magnetic field from space began more than 50 years ago. A continuous monitoring of the field using low Earth orbit (LEO) satellites, however, started only in 1999, and three satellites have taken highprecision measurements of the geomagnetic field during the past decade...... ability to characterize and understand the many sources that contribute to Earth’s magnetic field. In this review, we summarize investigations of Earth’s interior and environment that have been possible through the analysis of high-precision magnetic field observations taken by LEO satellites........ The unprecedented time-space coverage of their data opened revolutionary new possibilities for monitoring, understanding, and exploring Earth’s magnetic field. In the near future, the three-satellite constellation Swarm will ensure continuity of such measurement and provide enhanced possibilities to improve our...

  6. Satellite (Natural)

    Science.gov (United States)

    Murdin, P.

    2000-11-01

    In its most general sense, any celestial object in orbit around a similar larger object. Thus, for example, the Magellanic Clouds are satellite galaxies of our own Milky Way galaxy. Without qualification, the term is used to mean a body in orbit around a planet; an alternative term is moon. The term natural satellite distinguishes these bodies from artificial satellites—spacecraft placed in orbi...

  7. GA BASED SYNTHESIS OF SATELLITE-BORNE MULTI-BEAM PLANAR ARRAY WITH ARBITRARY GEOMETRY

    Institute of Scientific and Technical Information of China (English)

    Jin Jun; Wang Huali; Zhu Wenming; Liu Yunzhi

    2006-01-01

    A planar array antenna with arbitrary geometry synthesis technique based on genetic algorithm is discussed. This approach avoids coding/decoding and directly works with complex numbers to simplify computing program and to speed up computation. This approach uses two crossover operators that can overcome premature convergence and the dependence of convergence on initial population. Simulation results show that this method is capable of synthesizing complex pattern shapes of planar arrays with arbitrary geometry and can realize good sidelobe suppression at the same time.

  8. Seafloor characterisation using echo peak amplitudes of multibeam hydrosweep system - A preliminary study at Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Chakraborty, B.; Sudhakar, T.

    In this paper an interface to acquire 59-beams echo peak amplitudes of the Hydrosweep Multibeam system is established. The echo peak amplitude values collected at varying seabed provinces of Arabian sea are presented. The study reveals...

  9. Studies on normal incidence backscattering in nodule areas using the multibeam-hydrosweep system

    Digital Repository Service at National Institute of Oceanography (India)

    Pathak, D.; Chakraborty, B.

    The acoustic response from areas of varying nodule abundance and number densities in the Central Indian Ocean has been studied by using the echo peak amplitudes of the normal incidence beam in the Multibeam Hydrosweep system. It is observed...

  10. Fuzzy ARTMAP neural network for seafloor classification from multibeam sonar data

    Institute of Scientific and Technical Information of China (English)

    Zhou Xinghua; Chen Yongqi; Nick Emerson; Du Dewen

    2006-01-01

    This paper presents a seafloor classification method of multibeam sonar data, based on the use of Adaptive Resonance Theory (ART) neural networks. A general ART-based neural network, Fuzzy ARTMAP, has been proposed for seafloor classification of multibeam sonar data. An evolutionary strategy was used to generate new training samples near the cluster boundaries of the neural network, therefore the weights can be revised and refined by supervised learning. The proposed method resolves the training problem for Fuzzy ARTMAP neural networks, which are applied to seafloor classification of multibeam sonar data when there are less than adequate ground-truth samples. The results were synthetically analyzed in comparison with the standard Fuzzy ARTMAP network and a conventional Bayesian classifier.The conclusion can be drawn that Fuzzy ARTMAP neural networks combining with GA algorithms can be alternative powerful tools for seafloor classification of multibeam sonar data.

  11. Reson 8101ER Multibeam Sonar Data from Cruise AHI0605 - Main Hawaiian Islands

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Reson 8101ER multibeam Data were collected in 19-24 April and 28 April-11 May 2006 aboard NOAA Survey Launch Acoustic Habitat Investigator (AHI) in the Main Hawaiian...

  12. Characterizing biogenous sediments using multibeam echosounder backscatter data - Estimating power law parameter utilizing various models

    Digital Repository Service at National Institute of Oceanography (India)

    Chakraborty, B.; Kodagali, V.N.

    In this paper, Helmholtz-Kirchhoff (H-K) roughness model is employed to characterize seafloor sediment and roughness parameters from the eastern sector of the Southern Oceans The multibeam- Hydroswcep system's angular-backscatter data, which...

  13. Characterizing Indian Ocean manganese nodule-bearing seafloor using multi-beam angular backscatter

    Digital Repository Service at National Institute of Oceanography (India)

    Chakraborty, B.; Kodagali, V.N.

    backscattering in delineating seafloor parameters characteristic of nodule-rich sediments. In this paper, processed Hydrosweep multi-beam backscatter data from 45 spot locations in the CIOB (where nodule samples are available) were analysed to estimate seafloor...

  14. November 2007 Multibeam Mapping of South West corner of Pulley Ridge

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This disk or set of disks contain high-resolution multibeam and backscatter maps of the south-western corner of the Pulley Ridge Area, near the Tortugas, in the Gulf...

  15. Seabottom characterization using multibeam echosounder angular backscatter: An application of the composite roughness theory

    Digital Repository Service at National Institute of Oceanography (India)

    Chakraborty, B.; Schenke, H.W.; Kodagali, V.N.; Hagen, R.

    Composite roughness theory is used to characterize Southern Ocean bottom backscatter (multibeam) data. Spectral parameters based on Helmholtz-Kirchhof's theory (1) are determined from measured near-normal incidence values. A splicing technique using...

  16. 2005 Reson 8101ER Multibeam Sonar Data from Cruise AHI-05-01 - Northwestern Hawaiian Islands

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Reson 8101ER multibeam Data were collected from 4-23 April 2005 aboard NOAA Survey Launch Acoustic Habitat Investigator (AHI) at French Frigate Shoals in...

  17. 2005 Reson 8101ER Multibeam Sonar Data from Cruise AHI-05-04 - Main Hawaiian Islands

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Reson 8101ER multibeam Data were collected from 13 June-08 July 2005 aboard NOAA Survey Launch Acoustic Habitat Investigator (AHI) at Niihau, Penguin Bank, and...

  18. Multibeam Mapping of the West Florida Shelf, Gulf of Mexico, Twin Ridges Area

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — XYZ ASCII format high-resolution bathymetry data generated from the 2002 multibeam sonar survey of the West Florida Shelf, Gulf of Mexico.

  19. 2006 Reson 8101ER Multibeam Sonar Data from Cruise AHI-06-02 - American Samoa

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Reson 8101ER multibeam Data were collected in 10-13 Feb. and 18 Feb-13 Mar 2006 aboard NOAA Survey Launch Acoustic Habitat Investigator (AHI) in America Samoa at...

  20. CRED Reson 8101ER Multibeam Sonar Data from Cruise AHI0804 - Northwestern Hawaiian Islands, 2008

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Reson 8101ER multibeam Data were collected between 2 - 29 May 2008 aboard NOAA Survey Launch Acoustic Habitat Investigator (AHI) at French Frigate Shoals in the...

  1. 2007 Reson 8101ER Multibeam Sonar Data from Cruise AHI0701 - Wake Atoll

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Reson 8101ER multibeam Data were collected between 19 April - 9 May 2007 aboard NOAA Survey Launch Acoustic Habitat Investigator (AHI) at Wake Atoll, Western Pacific...

  2. CRED Reson 8101 multibeam backscatter data from the islands and banks in the Mariana archipelago, 2007.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Multibeam backscatter imagery extracted from gridded bathymetry of the Mariana archipelago between the U.S. Territory of Guam and Uracas Island in the Commonwealth...

  3. CRED 1 meter resolution Reson 8101 multibeam backscatter data of Wake Island, West Central Pacific, 2007.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Multibeam backscatter imagery extracted from gridded bathymetry of Wake Island, West Central Pacific.These data provide coverage between 0 and 200m meters. The...

  4. 2006 Multibeam Mapping of along-shelf corridor, between Madison-Swanson and Steamboat Lumps Florida

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This disk or set of disks contain high-resolution multibeam and backscatter maps of a long thin corridor at the shelf edge near he 74-m isobath spanning from...

  5. Reson 8101ER Multibeam Sonar Data from Cruise AHI1012 - Oahu, Main Hawaiian Islands

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Reson 8101ER multibeam Data were collected on December, 13 and December, 14, 2010 aboard NOAA Survey Launch Acoustic Habitat Investigator (AHI) in the Main Hawaiian...

  6. Reson 8101ER Multibeam Sonar Data from Cruise AHI1502 - Oahu, Main Hawaiian Islands

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Reson 8101ER multibeam Data were collected on April 24, 2015 aboard NOAA Survey Launch Acoustic Habitat Investigator (AHI) in the Main Hawaiian Islands at Oahu...

  7. Multibeam Backscatter Data for Selected U.S. Locations in the Pacific

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Multibeam backscatter imagery extracted from gridded bathymetry for selected U.S. locations in the Pacific. The backscatter datasets include data collected using the...

  8. Multibeam Mapping of the West Florida Shelf, Gulf of Mexico, Madison Swanson Area

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — XYZ ASCII format high-resolution bathymetry data generated from the 2002 multibeam sonar survey of the West Florida Shelf, Gulf of Mexico.

  9. Reliability of fish size estimates obtained from multibeam imaging sonar

    Science.gov (United States)

    Hightower, Joseph E.; Magowan, Kevin J.; Brown, Lori M.; Fox, Dewayne A.

    2013-01-01

    Multibeam imaging sonars have considerable potential for use in fisheries surveys because the video-like images are easy to interpret, and they contain information about fish size, shape, and swimming behavior, as well as characteristics of occupied habitats. We examined images obtained using a dual-frequency identification sonar (DIDSON) multibeam sonar for Atlantic sturgeon Acipenser oxyrinchus oxyrinchus, striped bass Morone saxatilis, white perch M. americana, and channel catfish Ictalurus punctatus of known size (20–141 cm) to determine the reliability of length estimates. For ranges up to 11 m, percent measurement error (sonar estimate – total length)/total length × 100 varied by species but was not related to the fish's range or aspect angle (orientation relative to the sonar beam). Least-square mean percent error was significantly different from 0.0 for Atlantic sturgeon (x̄  =  −8.34, SE  =  2.39) and white perch (x̄  = 14.48, SE  =  3.99) but not striped bass (x̄  =  3.71, SE  =  2.58) or channel catfish (x̄  = 3.97, SE  =  5.16). Underestimating lengths of Atlantic sturgeon may be due to difficulty in detecting the snout or the longer dorsal lobe of the heterocercal tail. White perch was the smallest species tested, and it had the largest percent measurement errors (both positive and negative) and the lowest percentage of images classified as good or acceptable. Automated length estimates for the four species using Echoview software varied with position in the view-field. Estimates tended to be low at more extreme azimuthal angles (fish's angle off-axis within the view-field), but mean and maximum estimates were highly correlated with total length. Software estimates also were biased by fish images partially outside the view-field and when acoustic crosstalk occurred (when a fish perpendicular to the sonar and at relatively close range is detected in the side lobes of adjacent beams). These sources of

  10. Building a Digital Library for Multibeam Data, Images and Documents

    Science.gov (United States)

    Miller, S. P.; Staudigel, H.; Koppers, A.; Johnson, C.; Cande, S.; Sandwell, D.; Peckman, U.; Becker, J. J.; Helly, J.; Zaslavsky, I.; Schottlaender, B. E.; Starr, S.; Montoya, G.

    2001-12-01

    The Scripps Institution of Oceanography, the UCSD Libraries and the San Diego Supercomputing Center have joined forces to establish a digital library for accessing a wide range of multibeam and marine geophysical data, to a community that ranges from the MGG researcher to K-12 outreach clients. This digital library collection will include 233 multibeam cruises with grids, plots, photographs, station data, technical reports, planning documents and publications, drawn from the holdings of the Geological Data Center and the SIO Archives. Inquiries will be made through an Ocean Exploration Console, reminiscent of a cockpit display where a multitude of data may be displayed individually or in two or three-dimensional projections. These displays will provide access to cruise data as well as global databases such as Global Topography, crustal age, and sediment thickness, thus meeting the day-to-day needs of researchers as well as educators, students, and the public. The prototype contains a few selected expeditions, and a review of the initial approach will be solicited from the user community during the poster session. The search process can be focused by a variety of constraints: geospatial (lat-lon box), temporal (e.g., since 1996), keyword (e.g., cruise, place name, PI, etc.), or expert-level (e.g., K-6 or researcher). The Storage Resource Broker (SRB) software from the SDSC manages the evolving collection as a series of distributed but related archives in various media, from shipboard data through processing and final archiving. The latest version of MB-System provides for the systematic creation of standard metadata, and for the harvesting of metadata from multibeam files. Automated scripts will be used to load the metadata catalog to enable queries with an Oracle database management system. These new efforts to bridge the gap between libraries and data archives are supported by the NSF Information Technology and National Science Digital Library (NSDL) programs

  11. Using a Multibeam Echosounder to Monitor AN Artificial Reef

    Science.gov (United States)

    Tassetti, A. N.; Malaspina, S.; Fabi, G.

    2015-04-01

    Artificial reefs (ARs) have become popular technological interventions in shallow water environments characterized by soft seabed for a wide number of purposes, from fisheries/environmental protection and enhancement to research and tourism. AR deployment has the potential for causing significant hydrographical and biological changes in the receiving environments and, in turn, ARs are strongly affected by the surrounding area in terms of spatial arrangement and structural integrity as well as colonization by benthic communities and finfish. In this context, ARs require a systematic monitoring program that a multibeam echosounder (MBES) can provide better than other sampling methods such as visual dives and ROV inspections that are not quantitative and often influenced by water visibility and diver experience/skills. In this paper, some subsequent MBES surveys of the Senigallia scientifically-planned AR (Northern Adriatic Sea) are presented and state-of-the art data processing and visualization techniques are used to draw post-reef deployment comparisons and quantify the evolution of the reef in terms of spatial arrangement and bulk volume. These multibeam surveys play a leading part in a general multi-year program, started simultaneously with the AR design and deployment and aimed to map how the reef structure quantitatively changes over time, as well as it affects the sea-bottom morphology and the fishery resource. All the data, surveyed over years making use of different sampling methods such as visual and instrumental echosounding observations and catch rate surveys, gain a mechanistic and predictive understanding of how the Senigallia AR functions ecologically and physically across spatial and temporal scales during its design life

  12. USING A MULTIBEAM ECHOSOUNDER TO MONITOR AN ARTIFICIAL REEF

    Directory of Open Access Journals (Sweden)

    A. N. Tassetti

    2015-04-01

    Full Text Available Artificial reefs (ARs have become popular technological interventions in shallow water environments characterized by soft seabed for a wide number of purposes, from fisheries/environmental protection and enhancement to research and tourism. AR deployment has the potential for causing significant hydrographical and biological changes in the receiving environments and, in turn, ARs are strongly affected by the surrounding area in terms of spatial arrangement and structural integrity as well as colonization by benthic communities and finfish. In this context, ARs require a systematic monitoring program that a multibeam echosounder (MBES can provide better than other sampling methods such as visual dives and ROV inspections that are not quantitative and often influenced by water visibility and diver experience/skills. In this paper, some subsequent MBES surveys of the Senigallia scientifically-planned AR (Northern Adriatic Sea are presented and state-of-the art data processing and visualization techniques are used to draw post-reef deployment comparisons and quantify the evolution of the reef in terms of spatial arrangement and bulk volume. These multibeam surveys play a leading part in a general multi-year program, started simultaneously with the AR design and deployment and aimed to map how the reef structure quantitatively changes over time, as well as it affects the sea-bottom morphology and the fishery resource. All the data, surveyed over years making use of different sampling methods such as visual and instrumental echosounding observations and catch rate surveys, gain a mechanistic and predictive understanding of how the Senigallia AR functions ecologically and physically across spatial and temporal scales during its design life

  13. Direct Broadcast Satellite: Radio Program

    Science.gov (United States)

    Hollansworth, James E.

    1992-01-01

    NASA is committed to providing technology development that leads to the introduction of new commercial applications for communications satellites. The Direct Broadcast Satellite-Radio (DBS-R) Program is a joint effort between The National Aeronautics and Space Administration (NASA) and The United States Information Agency/Voice of America (USIA/VOA) directed at this objective. The purpose of this program is to define the service and develop the technology for a direct-to-listener satellite sound broadcasting system. The DBS-R Program, as structured by NASA and VOA, is now a three-phase program designed to help the U.S. commercial communications satellite and receiver industry bring about this new communications service. Major efforts are being directed towards frequency planning hardware and service development, service demonstration, and experimentation with new satellite and receiver technology.

  14. Multi-frequency AOM for multi-beam laser scanning exposure system

    Science.gov (United States)

    Shinada, Hidetoshi

    2016-10-01

    Digital printing systems recorded on films or computer to plates (CTPs) have been required to improve their productivity and image quality. Under the circumstance, a printing technology of the multi-beam laser scanning for the drum capstan system, which is almost the same as optics configuration as the flat bed system, was developed using a newly developed multi-frequency acousto-optic modulator (AOM) as a key device instead of ultra-fast scanning devices toward a main scan direction. The multi-frequency AOM was developed with phased array-type transducers, achieving a wider bandwidth of over 160 MHz. The design consisted of a simultaneous three beams generation with interlace scan to avoid the beat effect by adjacent Doppler-shifted beams, which consequently attained the fastest recording speed of 5.0 mm/s compared with 2.0-3.0 mm/s of existing systems in those days. Furthermore, a couple of critical parameters of the multi-frequency AOM are studied, for example, a treatment of third-order intermodulation and also beat effect in connection with photosensitive media. As a result, the necessity of interlaces scanning to obtain good image quality without beat effect and also to allow a lower laser power to apply is proposed.

  15. Scientific Satellites

    Science.gov (United States)

    1967-01-01

    followed Hale’s into orbit. In 1879, Jules Verne wrote about launching small satellites with a gun possessing a muzzle velocity of 10 000 m/sec (ref. 3...was activated in 1950.11 It was located only a few tens of miles from the spot where Jules Verne had his Baltimore Gun Club fire a manned projectile to...principle, satellites can be launched by a single impulse applied at the Earth’s surface-say, with a large cannon, & la Jules Verne (sec. 8-3). In

  16. Inter-satellite links for satellite autonomous integrity monitoring

    Science.gov (United States)

    Rodríguez-Pérez, Irma; García-Serrano, Cristina; Catalán Catalán, Carlos; García, Alvaro Mozo; Tavella, Patrizia; Galleani, Lorenzo; Amarillo, Francisco

    2011-01-01

    A new integrity monitoring mechanisms to be implemented on-board on a GNSS taking advantage of inter-satellite links has been introduced. This is based on accurate range and Doppler measurements not affected neither by atmospheric delays nor ground local degradation (multipath and interference). By a linear combination of the Inter-Satellite Links Observables, appropriate observables for both satellite orbits and clock monitoring are obtained and by the proposed algorithms it is possible to reduce the time-to-alarm and the probability of undetected satellite anomalies.Several test cases have been run to assess the performances of the new orbit and clock monitoring algorithms in front of a complete scenario (satellite-to-satellite and satellite-to-ground links) and in a satellite-only scenario. The results of this experimentation campaign demonstrate that the Orbit Monitoring Algorithm is able to detect orbital feared events when the position error at the worst user location is still under acceptable limits. For instance, an unplanned manoeuvre in the along-track direction is detected (with a probability of false alarm equals to 5 × 10-9) when the position error at the worst user location is 18 cm. The experimentation also reveals that the clock monitoring algorithm is able to detect phase jumps, frequency jumps and instability degradation on the clocks but the latency of detection as well as the detection performances strongly depends on the noise added by the clock measurement system.

  17. Radio interferometry and satellite tracking

    CERN Document Server

    Kawase, Seiichiro

    2012-01-01

    Worldwide growth of space communications has caused a rapid increase in the number of satellites operating in geostationary orbits, causing overcrowded orbits. This practical resource is designed to help professionals overcome this problem. This timely book provides a solid understanding of the use of radio interferometers for tracking and monitoring satellites in overcrowded environments. Practitioners learn the fundamentals of radio interferometer hardware, including antennas, receiving equipment, signal processing and phase detection, and measurement accuracies. This in-depth volume describ

  18. The french educational satellite arsene

    Science.gov (United States)

    Danvel, M.; Escudier, B.

    ARSENE (Ariane, Radio-amateur, Satellite pour l'ENseignement de l'Espace) is a telecommunications satellite for Amateur Space Service. Its main feature is that more than 100 students from French engineering schools and universities have been working since 1979 for definition phase and satellite development. The highest IAF awards has been obtained by "ARSENE students" in Tokyo (1980) and Rome (1981). The French space agency, CNES and French aerospace industries are supporting the program. The European Space Agency offered to place ARSENE in orbit on the first Ariane mark IV launch late 1985.

  19. NASA's mobile satellite communications program; ground and space segment technologies

    Science.gov (United States)

    Naderi, F.; Weber, W. J.; Knouse, G. H.

    1984-10-01

    This paper describes the Mobile Satellite Communications Program of the United States National Aeronautics and Space Administration (NASA). The program's objectives are to facilitate the deployment of the first generation commercial mobile satellite by the private sector, and to technologically enable future generations by developing advanced and high risk ground and space segment technologies. These technologies are aimed at mitigating severe shortages of spectrum, orbital slot, and spacecraft EIRP which are expected to plague the high capacity mobile satellite systems of the future. After a brief introduction of the concept of mobile satellite systems and their expected evolution, this paper outlines the critical ground and space segment technologies. Next, the Mobile Satellite Experiment (MSAT-X) is described. MSAT-X is the framework through which NASA will develop advanced ground segment technologies. An approach is outlined for the development of conformal vehicle antennas, spectrum and power-efficient speech codecs, and modulation techniques for use in the non-linear faded channels and efficient multiple access schemes. Finally, the paper concludes with a description of the current and planned NASA activities aimed at developing complex large multibeam spacecraft antennas needed for future generation mobile satellite systems.

  20. NASA's mobile satellite communications program; ground and space segment technologies

    Science.gov (United States)

    Naderi, F.; Weber, W. J.; Knouse, G. H.

    1984-01-01

    This paper describes the Mobile Satellite Communications Program of the United States National Aeronautics and Space Administration (NASA). The program's objectives are to facilitate the deployment of the first generation commercial mobile satellite by the private sector, and to technologically enable future generations by developing advanced and high risk ground and space segment technologies. These technologies are aimed at mitigating severe shortages of spectrum, orbital slot, and spacecraft EIRP which are expected to plague the high capacity mobile satellite systems of the future. After a brief introduction of the concept of mobile satellite systems and their expected evolution, this paper outlines the critical ground and space segment technologies. Next, the Mobile Satellite Experiment (MSAT-X) is described. MSAT-X is the framework through which NASA will develop advanced ground segment technologies. An approach is outlined for the development of conformal vehicle antennas, spectrum and power-efficient speech codecs, and modulation techniques for use in the non-linear faded channels and efficient multiple access schemes. Finally, the paper concludes with a description of the current and planned NASA activities aimed at developing complex large multibeam spacecraft antennas needed for future generation mobile satellite systems.

  1. Olympic Coast National Marine Sanctuary - mos110_0204b.tif - Multibeam backscatter mosaic from survey area 110_0204b

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A multibeam backscatter image (0-35 m water depths) mosaiced from hydrographic data collected during a August/September 2003seafloor survey. A Reson 8101 multibeam...

  2. Olympic Coast National Marine Sanctuary - mos110_0204c.tif - Multibeam backscatter mosaic from survey area 110_0204c

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A multibeam backscatter image (0-35 m water depths) mosaiced from hydrographic data collected during a August/September 2003seafloor survey. A Reson 8101 multibeam...

  3. Olympic Coast National Marine Sanctuary - mos110_0204a.tif - Multibeam backscatter mosaic from survey area 110_0204a

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A multibeam backscatter image (0-35 m water depths) mosaiced from hydrographic data collected during a July/August 2002seafloor survey. A Reson 8101 multibeam...

  4. Designing and implementing Multibeam Smart Antennas for high bandwidth UAV communications using FPGAs

    Science.gov (United States)

    Porcello, J. C.

    Requirements for high bandwidth UAV communications are often necessary in order to move large amounts of mission information to/from Users in real-time. The focus of this paper is antenna beamforming for point-to-point, high bandwidth UAV communications in order to optimize transmit and receive power and support high data throughput communications. Specifically, this paper looks at the design and implementation of Multibeam Smart Antennas to implement antenna beamforming in an aerospace communications environment. The Smart Antenna is contrasted against Fast Fourier Transform (FFT) based beamforming in order to quantify the increase in both computational load and FPGA resources required for multibeam adaptive signal processing in the Smart Antenna. The paper begins with an overall discussion of Smart Antenna design and general beamforming issues in high bandwidth communications. Important design considerations such as processing complexity in a constrained Size, Weight and Power (SWaP) environment are discussed. The focus of the paper is with respect to design and implementation of digital beamforming wideband communications waveforms using FPGAs. A Multibeam Time Delay element is introduced based on Lagrange Interpolation. Design data for Multibeam Smart Antennas in FPGAs is provided in the paper as well as reference circuits for implementation. Finally, an example Multibeam Smart Antenna design is provided based on a Xilinx Virtex-7 FPGA. The Multibeam Smart Antenna example design illustrates the concepts discussed in the paper and provides design insight into Multibeam Smart Antenna implementation from the point of view of implementation complexity, required hardware, and overall system performance gain.

  5. Techniques for computing regional radiant emittances of the earth-atmosphere system from observations by wide-angle satellite radiometers, phase 3

    Science.gov (United States)

    Pina, J. F.; House, F. B.

    1975-01-01

    Radiometers on earth orbiting satellites measure the exchange of radiant energy between the earth-atmosphere (E-A) system and space at observation points in space external to the E-A system. Observations by wideangle, spherical and flat radiometers are analyzed and interpreted with regard to the general problem of the earth energy budget (EEB) and to the problem of determining the energy budget of regions smaller than the field of view (FOV) of these radiometers.

  6. A Geometry-Based Cycle Slip Detection and Repair Method with Time-Differenced Carrier Phase (TDCP for a Single Frequency Global Position System (GPS + BeiDou Navigation Satellite System (BDS Receiver

    Directory of Open Access Journals (Sweden)

    Chuang Qian

    2016-12-01

    Full Text Available As the field of high-precision applications based on carriers continues to expand, the development of low-cost, small, modular receivers and their application in diverse scenarios and situations with complex data quality has increased the requirements of carrier-phase data preprocessing. A new geometry-based cycle slip detection and repair method based on Global Position System (GPS + BeiDou Navigation Satellite System (BDS is proposed. The method uses a Time-differenced Carrier Phase (TDCP model, which eliminates the Inner-System Bias (ISB between GPS and BDS, and it is conducive to the effective combination of GPS and BDS. It avoids the interference of the noise of the pseudo-range with cycle slip detection, while the cycle slips are preserved as integers. This method does not limit the receiver frequency number, and it is applicable to single-frequency data. The process is divided into two steps to detect and repair cycle slip. The first step is cycle slip detection, using the Improved Local Analysis Method (ILAM to find satellites that have cycle slips; The second step is to repair the cycle slips, including estimating the float solution of changes in ambiguities at the satellites that have cycle slips with the least squares method and the integer solution of the cycle slips by rounding. In the process of rounding, in addition to the success probability, a decimal test is carried out to validate the result. Finally, experiments with filed test data are carried out to prove the effectiveness of this method. The results show that the detectable cycle slips number with GPS + BDS is much greater than that with GPS. The method can also detect the non-integer outliers while fixing the cycle slip. The maximum decimal bias in repair is less than that with GPS. It implies that this method takes full advantages of multi-system.

  7. A Geometry-Based Cycle Slip Detection and Repair Method with Time-Differenced Carrier Phase (TDCP) for a Single Frequency Global Position System (GPS) + BeiDou Navigation Satellite System (BDS) Receiver.

    Science.gov (United States)

    Qian, Chuang; Liu, Hui; Zhang, Ming; Shu, Bao; Xu, Longwei; Zhang, Rufei

    2016-12-05

    As the field of high-precision applications based on carriers continues to expand, the development of low-cost, small, modular receivers and their application in diverse scenarios and situations with complex data quality has increased the requirements of carrier-phase data preprocessing. A new geometry-based cycle slip detection and repair method based on Global Position System (GPS) + BeiDou Navigation Satellite System (BDS) is proposed. The method uses a Time-differenced Carrier Phase (TDCP) model, which eliminates the Inner-System Bias (ISB) between GPS and BDS, and it is conducive to the effective combination of GPS and BDS. It avoids the interference of the noise of the pseudo-range with cycle slip detection, while the cycle slips are preserved as integers. This method does not limit the receiver frequency number, and it is applicable to single-frequency data. The process is divided into two steps to detect and repair cycle slip. The first step is cycle slip detection, using the Improved Local Analysis Method (ILAM) to find satellites that have cycle slips; The second step is to repair the cycle slips, including estimating the float solution of changes in ambiguities at the satellites that have cycle slips with the least squares method and the integer solution of the cycle slips by rounding. In the process of rounding, in addition to the success probability, a decimal test is carried out to validate the result. Finally, experiments with filed test data are carried out to prove the effectiveness of this method. The results show that the detectable cycle slips number with GPS + BDS is much greater than that with GPS. The method can also detect the non-integer outliers while fixing the cycle slip. The maximum decimal bias in repair is less than that with GPS. It implies that this method takes full advantages of multi-system.

  8. Multibeam Mapping of Remote Fjords in Southeast-Greenland

    Science.gov (United States)

    Weinrebe, W.; Kjaer, K. H.; Kjeldsen, K. K.; Bjork, A. A.

    2015-12-01

    The fjords of Southeast-Greenland are among the most remote areas of the Northern Hemisphere. Access to this area is hampered by a broad belt of sea ice floating along the East-Greenland coast from North to South. Consequently, the majority of those fjords have never been surveyed in detail until now. During an expedition by the Center of GeoGenetics of the University of Copenhagen in summer of 2014 we were able to map the Skjoldungen Fjord system with multibeam bathymetry. The topsail schooner ACTIV, built 1951 as a cargo ship to supply remote settlements in Greenland was chosen for the expedition. Though a vintage vessel, the ACTIV was well suited to cross the belt of sea ice and to cruise the ice covered fjords. A portable ELAC-Seabeam 1050 multibeam system was temporarily installed on the vessel. The two transducer of the system were mounted at the lower end of a 6 m long pole attached outboard at port side to the hull of the vessel. Though the installation was quite demanding without any winches or cranes, the construction was sufficiently stable and easy to manage throughout the entire cruise. Nearly the entire fjord system, leaving only a small gap of 5 km at the innermost part and small stripes close to the shorelines could be surveyed during the cruise. For the first time, a comprehensive map of Skjoldungen Fjord is now available. The map displays water depths from close to zero up to 800 m, the deepest part along a stretch of about 10 km in the Southwest. The bathymetry of the northern fjord is remarkably different from the southern fjord: the southern fjord features an outer deep part showing water depths between 500 m and 800 m and a shallow inner part with depths less than 300 m and a prominent sill in between. The northern fjord shows a more gradual increase of water depths from 200 m in the inner part to 600 m at the entrance.

  9. Multibeam Sonar Data since 2003 - Cruise Metadata (NOAA Ship Hi'ialakai and R/V AHI)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Multibeam sonar data have collected for selected U.S. locations in the Pacific using a RESON 8101ER multibeam sonar, Kongsberg 300 kHz EM3002D, and a Kongsberg 30...

  10. Principles And Design Of Multibeam Interference Devices: A Microelectromechanical-Systems Segment-Deformable-Mirror-Based Adaptive Spectrum Attenuator

    OpenAIRE

    Huang, Z.Y.; Zhu, Y. Z.; Wang, Anbo

    2005-01-01

    Fourier analysis of multibeam interference shows that the total electric field and relative time delay of the beams form a Fourier-transform pair. Fourier-analysis-based multibeam interference analysis and device design is discussed in detail. The principle of the proposed segment-deformable-mirror-based adaptive spectrum attenuator is illustrated. (c) 2005 Optical Society of America.

  11. Report for simultaneous, multiple independently steered beam study for Airborne Electronically Steerable Phased Array (AESPA) program

    Science.gov (United States)

    1978-01-01

    Design concepts of an array for the formation of multiple, simultaneous, independently pointed beams for satellite communication links were investigated through tradeoffs of various approaches which were conceived as possible solutions to the problem. After the preferred approach was selected, a more detailed design was configured and is presented as a candidate system that should be given further consideration for development leading to a preliminary design. This array uses an attenuator and a phase shifter with every element. The aperture excitation necessary to form the four beams is calculated and then placed across the array using these devices. Pattern analysis was performed for two beam and four beam cases with numerous patterns being presented. Parameter evaluation shown includes pointing accuracy and beam shape, sidelobe characteristics, gain control, and beam normalization. It was demonstrated that a 4 bit phase shifter and a 6 bit, 30 dB attenuator were sufficient to achieve adequate pattern performances. The phase amplitude steered multibeam array offers the flexibility of 1 to 4 beams with an increase in gain of 6 dB if only one beam is selected.

  12. Discs of Satellites: the new dwarf spheroidals

    CERN Document Server

    Metz, Manuel; Jerjen, Helmut

    2009-01-01

    The spatial distributions of the most recently discovered ultra faint dwarf satellites around the Milky Way and the Andromeda galaxy are compared to the previously reported discs-of-satellites (DoS) of their host galaxies. In our investigation we pay special attention to the selection bias introduced due to the limited sky coverage of SDSS. We find that the new Milky Way satellite galaxies follow closely the DoS defined by the more luminous dwarfs, thereby further emphasizing the statistical significance of this feature in the Galactic halo. We also notice a deficit of satellite galaxies with Galactocentric distances larger than 100 kpc that are away from the disc-of-satellites of the Milky Way. In the case of Andromeda, we obtain similar results, naturally complementing our previous finding and strengthening the notion that the discs-of-satellites are optical manifestations of a phase-space correlation of satellite galaxies.

  13. Monitoring Large-Scale Sediment Transport Dynamics with Multibeam Sonar

    Science.gov (United States)

    Parsons, D. R.; Simmons, S. M.; Best, J. L.; Keevil, G. M.; Oberg, K.; Czuba, J. A.

    2009-05-01

    Multibeam Echo-Sounder systems have developed rapidly over recent decades and are routinely deployed to provide high-resolution bathymetric information in and range of environments. Modern data handling and storage technologies now facilitate the logging of the raw acoustic back-scatter information that was previously discarded by these systems. This paper describes methodologies that exploit this logging capability to quantify both the concentration and dynamics of suspended sediment within the water column. This development provides a multi-purpose tool for the holistic surveying of sediment transport dynamics by imaging suspended sediment concentration, the associated flows and providing concurrent high-resolution bathymetry. Results obtained a RESON 7125 MBES are presented from both well constrained dock-side testing and full field deployment over dune bedforms in the Mississippi. The capacity of the system to image suspended sediment structures is demonstrated and a novel methodology for estimating 2D flow velocities, based on frame cross-correlation methods, is introduced. The results demonstrate the capability of MBES systems to successfully map spatial and temporal variations in suspended sediment concentration throughout a 2D swath and application of the velocity estimation algorithms allow real-time holistic monitoring of turbulent flow processes and suspended sediment fluxes at a scale previously unrealisable. Turbulent flow over a natural dune bedform on the Mississippi is used to highlight the process information provided and the insights that can be gleaned for this technical development.

  14. Fluvial Morphodynamics: advancing understanding using Multibeam Echo Sounders (MBES)

    Science.gov (United States)

    Parsons, D. R.; Best, J. L.

    2012-12-01

    Accurately and reliably determining riverbed morphology is key to understanding linkages between flow fields, sediment transport and bed roughness in a range of aquatic environments, including large fluvial channels. Modern shallow-water multibeam echo sounder (MBES) systems are now allowing us to acquire bathymetric data at unprecedented resolutions that are millimetric in precision and centimetric in accuracy. Such systems, and the morphological resolution they can supply, are capable of revealing the complex three-dimensional patterns in riverbed morphology that are facilitating a holistic examination of system morphodynamics, at the field scale, that was unimaginable just a few years ago. This paper presents a range of MBES acquired examples to demonstrate how the methodological developments in this technology are leading to advances in our substantive understanding of large river systems. This includes examples that show linkages across scales, and in particular the morphodynamics of superimposed bedforms and bars revealed by such high-resolution data, which have broad implications for a range of applications, including flood prediction, engineering design and reconstructing ancient sedimentary environments.

  15. Electron optics of multi-beam scanning electron microscope

    Energy Technology Data Exchange (ETDEWEB)

    Mohammadi-Gheidari, A., E-mail: A.M.Gheidari@tudelft.nl [Delft University of Technology, Lorentzweg 1, 2628 CJ Delft (Netherlands); Kruit, P. [Delft University of Technology, Lorentzweg 1, 2628 CJ Delft (Netherlands)

    2011-07-21

    We have developed a multi-beam scanning electron microscope (MBSEM), which delivers a square array of 196 focused beams onto a sample with a resolution and current per beam comparable to a state of the art single beam SEM. It consists of a commercially available FEI Nova-nano 200 SEM column equipped with a novel multi-electron beam source module. The key challenge in the electron optical design of the MBSEM is to minimize the off-axial aberrations of the lenses. This article addresses the electron optical design of the system and presents the result of optics simulations for a specific setting of the system. It is shown that it is possible to design a system with a theoretical axial spot size of 1.2 nm at 15 kV with a probe current of 26 pA. The off-axial aberrations for the outermost beam add up 0.8 nm, increasing the probe size to 1.5 nm.

  16. Multibeam Electron Source using MEMS Electron Optical Components

    Energy Technology Data Exchange (ETDEWEB)

    Someren, B van; Bruggen, M J van; Zhang, Y; Hagen, C W; Kruit, P [Delft University of Technology, Lorentzweg 1, 2628 CJ Delft (Netherlands)

    2006-04-01

    Recent developments in electron beam equipment have given rise to ever more complex electron optical (EO) designs. Until now these designs were realized using standard workshop techniques like drilling, turning etc. With the need for even more complex designs to advance electron optics, we use the possibilities of manufacturing EO components with MEMS fabrication techniques. This leads to different design rules in the EO design. One can use one of the strong points of MEMS fabrication, mass manufacturing of identical and reliable components within tight specifications. One of our designs that demonstrates this is presented in this paper, the multi-beam electron source. We are developing an electron source for use in a standard scanning electron microscope that produces 100 beams instead of one. The design is made so that the performance in terms of spot size and current per beam is equal to the performance of the beam from a single beam source, around 1 nm and 25 pA. Furthermore, since we modify the SEM for nanolithography purposes, it is necessary to switch each of the individual beams on and off. For that purpose we integrate an array of blanker electrodes in the source unit.

  17. A 6.5-GHz Multibeam Pulsar Survey

    CERN Document Server

    Bates, S D; Lorimer, D R; Kramer, M; Possenti, A; Burgay, M; Stappers, B; Keith, M J; Lyne, A; Bailes, M; McLaughlin, M A; O'Brien, J T; Hobbs, G

    2010-01-01

    A survey of the Galactic plane in the region $-60\\degree \\leq l \\leq 30\\degree$, $|b| \\leq 0.25\\degree$ was carried out using the seven-beam Parkes Methanol Multibeam (MMB) receiver, which operates at a frequency of 6.5 GHz. Three pulsars were discovered, and 16 previously known pulsars detected. In this paper we present two previously-unpublished discoveries, both with extremely high dispersion measures, one of which is very close, in angular distance, to the Galactic centre. The survey data also contain the first known detection, at radio frequencies, of the radio magnetar PSR J1550-5418. Our survey observation was made 46 days prior to that previously published and places constraints on the beginning of pulsed radio emission from the source. The detection of only three previously undiscovered pulsars argues that there are few pulsars in the direction of the inner Galaxy whose flux density spectrum is governed by a flat power law. However, these pulsars would be likely to remain undetected at lower frequenc...

  18. The 6-GHz Multibeam Maser Survey I. Techniques

    CERN Document Server

    Green, J A; Fuller, G A; Avison, A; Breen, S L; Brooks, K; Burton, M G; Chrysostomou, A; Cox, J; Diamond, P J; Ellingsen, S P; Gray, M D; Hoare, M G; Masheder, M R W; McClure-Griffiths, N M; Pestalozzi, M; Phillips, C; Quinn, L; Thompson, M A; Voronkov, M; Walsh, A; Ward-Thompson, D; Wong-McSweeney, D; Yates, J A; Cohen, R J

    2008-01-01

    A new 7-beam 6-7 GHz receiver has been built to survey the Galaxy and the Magellanic Clouds for newly forming high-mass stars that are pinpointed by strong methanol maser emission at 6668 MHz. The receiver was jointly constructed by Jodrell Bank Observatory (JBO) and the Australia Telescope National Facility (ATNF) and allows simultaneous coverage at 6668 and 6035 MHz. It was successfully commissioned at Parkes in January 2006 and is now being used to conduct the Parkes-Jodrell multibeam maser survey of the Milky Way. This will be the first systematic survey of the entire Galactic plane for masers of not only 6668-MHz methanol, but also 6035-MHz excited-state hydroxyl. The survey is two orders of magnitude faster than most previous systematic surveys and has an rms noise level of ~0.17 Jy.This paper describes the observational strategy, techniques and reduction procedures of the Galactic and Magellanic Cloud surveys, together with deeper, pointed, follow-up observations and complementary observations with oth...

  19. A parallel multibeam mask writing method and its impact on data volumes

    Science.gov (United States)

    Chaudhary, N.; Luo, Y.; Savari, S. A.

    2016-10-01

    The pattern requirements for mask writers have steadily been growing, and there is considerable interest in multibeam mask writers to handle the throughput and resolution challenges associated with the needs of sub- 10nm technology nodes. The mask writer of the future will process terabits of information per second and deal with petabytes of data. In this paper, we investigate lossless data compression and system parallelism together to address part of the data transfer problem. We explore simple compression algorithms and the effect of parallelism on the total compressed data in a multibeam system architecture motivated by the IMS Nanofabrication multibeam mask writer series eMET. We model the shot assignment problem and beam shot overlap by means of two-dimensional linear spatial filtering on an image. We describe a fast scanning strategy and investigate data volumes for a family of beam arrays with 2N ×(2N -1) beams, where N is an odd integer.

  20. Scattered and Reflected Light Polarimetry as a Diagnostic of Multibeam Hohlraum Physics

    Science.gov (United States)

    Turnbull, David

    2015-11-01

    Scattered light provides a window into the complex laser-plasma interactions and hydrodynamics occurring within indirect-drive inertial confinement fusion (ICF) hohlraums. Understanding hohlraum physics is an important part of developing improved targets and increasing the likelihood of ignition. Measurements of the scattered light power and spectrum are routinely made on each cone of beams at the National Ignition Facility (NIF) in order to correct for coupling losses due to laser-plasma instabilities. The additional ability to probe scattered light polarization on a 30° incidence beam was recently added, which has produced a number of discoveries regarding multibeam hohlraum physics. One particularly important insight is that the polarizations of an incident beam and its backscatter are affected by amplitude and phase modulations induced by crossing laser beams. The revised theory describing this optical wave mixing has recently been validated by conducting a two beam pump-probe experiment under carefully controlled conditions. This effect could be utilized more generally to produce ultrafast, damage-resistant, and tunable laser-plasma wave plates, polarizers, or other photonic devices. It also enables remote polarimetry-based probing of plasma conditions such as electron temperature. To extract more quantitative feedback about crossed-beam energy transfer (CBET) from the polarimetry data in ICF experiments at the NIF, the diagnostic has been upgraded to measure the complete Stokes vector with temporal resolution. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  1. Multibeam mapping of the West Florida Shelf, Gulf of Mexico

    Science.gov (United States)

    Gardner, James V.; Dartnell, Peter; Sulak, Kenneth J.

    2002-01-01

    A zone of deep-water reefs is thought to extend from the mid and outer shelf south of Mississippi and Alabama to at least the northwestern Florida shelf off Panama City, Florida (Figure 1). The reefs off Mississippi and Alabama are found in water depths of 60 to 120 m (Ludwick and Walton, 1957; Gardner et al., 2001, in press) and were the focus of a multibeam echosounder (MBES) mapping survey by the U.S. Geological Survey (USGS) in 2000 (Gardner et al., 2000, Gardner et al., 2001, in press). If this deep-water-reef trend does exist along the northwestern Florida shelf, then it is critical to determine the accurate geomorphology and reef type that occur because of their importance as benthic habitats for fisheries. Georeferenced high-resolution mapping of bathymetry is a fundamental first step in the study of areas suspected to be critical habitats. Morphology is thought to be critical to defining the distribution of dominant demersal plankton/planktivores communities. Fish faunas of shallow hermatypic reefs have been well studied, but those of deep ahermatypic reefs have been relatively ignored. The ecology of deep-water ahermatypic reefs is fundamentally different from hermatypic reefs because autochthonous intracellular symbiotic zooxanthellae (the carbon source for hermatypic corals) do not form the base of the trophic web in ahermatypic reefs. Instead, exogenous plankton, transported to the reef by currents, serves as the primary carbon source. Thus, one of the principle uses of the morphology data will be to identify whether any reefs found are hermatypic or ahermatypic in origin.

  2. Ballistic missile tracking performance in boost phase based on dual infrared early warning satellites%红外预警双星弹道导弹主动段跟踪性能

    Institute of Scientific and Technical Information of China (English)

    钟宇; 吴晓燕; 黄树彩; 吴建峰; 李成景; 唐意东

    2015-01-01

    为研究反导作战中红外预警卫星系统对弹道导弹主动段弹道的跟踪性能,提出以后验克拉美-罗下界(Posterior Cramer-Rao Lower Bound, PCRLB)为衡量指标,结合8态重力转弯主动段运动模型和双星纯方位无源定位获取的量测量,系统分析了运动建模精度、量测精度、采样周期、测源不确定性下检测概率和虚警数目等因素对跟踪时效性和准确性的影响.仿真算例给出了上述因素对位置和速度跟踪性能的影响程度和规律,可为预警卫星反导作战、战技指标关联建模以及星载探测器优化设计等提供有意义的参考.%To study the ballistic missile tracking performance in boost phase based on infrared early warning satellites system, Posterior Cramer-Rao Lower Bound (PCRLB) was proposed as a measurement index. After modeling ballistic target motion by 8-state gravity turn model and locating target position by dual satellites' bearing-only passive localization, PCRLB was used to evaluate the effects of factors, including target motion model accuracy, measurement accuracy, sampling period, detection probability and false alarm number conditioned by measurement origin uncertainty, on tracking timeliness and accuracy. One simulation example showed the extent and rules of said factors on position and tracking performance of velocity. It can contribute to the anti-ballistic missile operation by early warning satellite, the relationship modeling between tactical and technical indices and the optimal design of satellite-based infrared detector.

  3. Geostationary Satellite (GOES) Images

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Visible and Infrared satellite imagery taken from radiometer instruments on SMS (ATS) and GOES satellites in geostationary orbit. These satellites produced...

  4. L-shell bifurcation of electron outer belt at the recovery phase of geomagnetic storm as observed by STEP-F and SphinX instruments onboard the CORONAS-Photon satellite

    Science.gov (United States)

    Dudnik, Oleksiy; Sylwester, Janusz; Kowalinski, Miroslaw; Podgorski, Piotr

    2016-07-01

    Radiation belts and sporadically arising volumes comprising enhanced charged particle fluxes in the Earth's magnetosphere are typically studied by space-borne telescopes, semiconductor, scintillation, gaseous and other types of detectors. Ambient and internal electron bremsstrahlung in hard X-ray arises as a result of interaction of precipitating particles with the atmosphere (balloon experiments) and with the satellite's housings and instrument boxes (orbital experiments). Theses emissions provide a number of new information on the physics of radiation belts. The energies of primary electrons and their spectra responsible for measured X-ray emissions remain usually unknown. Combined measurements of particle fluxes, and their bremsstrahlung by individual satellite instruments placed next to each other provide insight to respective processes. The satellite telescope of electrons and protons STEP-F and the solar X-ray spectrophotometer SphinX were placed in close proximity to each other aboard CORONAS-Photon, the low, circular and highly inclined orbit satellite. Based on joint analysis of the data we detected new features in the high energy particle distributions of the Earth's magnetosphere during deep minimum of solar activity [1-3]. In this research the bifurcation of Van Allen outer electron radiation belt during the weak geomagnetic storm and during passage of interplanetary shock are discussed. Outer belt bifurcation and growth of electron fluxes in a wide energy range were recorded by both instruments during the recovery phase of May 8, 2009 substorm. STEP-F recorded also barely perceptible outer belt splitting on August 5, 2009, after arrival of interplanetary shock to the Earth's magnetosphere bowshock. The STEP-F and SphinX data are compared with the space weather indexes, and with relativistic electron fluxes observed at geostationary orbit. We discuss possible mechanism of the phenomena consisting in the splitting of drift shells because of Earth

  5. Neptune's small satellites

    Science.gov (United States)

    Thomas, P.

    1992-04-01

    The small satellites of Neptune and other planets discovered during the Voyager 2 mission are discussed in terms of their composition and relationship to the planetary systems. The satellite Proteus is described in terms of its orbit, five other satellites are described, and they are compared to ther small satellites and systems. Neptune's satellites are hypothesized to be related to the ring system, and the satellite Galatea is related to the confinement of the rings.

  6. 傅里叶相位差谱在卫星目标图像检测中的应用%Algorithm of Autonomous Satellite Recognition Base on Fourier Phase Difference

    Institute of Scientific and Technical Information of China (English)

    张少迪; 王延杰; 孙宏海

    2011-01-01

    提出一种利用序列图像傅里叶相位差谱的特征检测卫星目标的算法.欲跟踪的卫星目标往往淹没在星海中,仅仅依据星体特征检测出目标很繁琐,也很困难.从傅里叶变换的相谱差异特性出发,将序列图像相邻2帧图像中的前一帧图像通过相谱补偿后与后一帧图像对比,检测出奇异的卫星目标,再利用帧差法剔除伪目标,给出跟踪目标的运动轨迹.同时,为了提高该算法的抗噪声能力,针对遇到的实际情况提出基于二维直方图改进的图像二值化算法.通过实验验证了该算法的可行性,结果表明,所提出算法的检测误差与人工捕获相比不超过1个像素.%An algorithm is designed to recognize satellites in the sky based on phase difference of a series of images in frequency domain. It is complicated and difficult to recognize the satellites merely through stars' characteristics because the satellites traced are always surrounded by a large number of stars. One frame image in a series of images is compensated and compared with its adjacent frame. From the comparison , the odd object can be recognized by the character of Fourier phase difference. Then frame subtraction method is used to eliminate fake objects. Finally the movement of tracing object is described. Meanwhile an improved algorithm of image binarization based on two-dimension histogram is designed to strength its anti-noise ability. At the end the experiment shows that the error between this algorithm recognition and human capture is less than one pixel.

  7. A simple ship-borne antenna stabilizer for limited area maritime satellite communication systems

    Science.gov (United States)

    Satoh, K.; Nakamae, M.; Mishima, H.

    1984-10-01

    This paper deals with a simple ship-borne antenna stabilizer for use in limited area multi-beam maritime satellite communication systems. A limited area system with high satellite e.i.r.p. is expected to be a more economical satellite system than a global system, because a low-gain ship-borne antenna and a simplified antenna stabilizer can be used. An optimum configuration is proposed for small size and low cost pendulum-type antenna stabilizers which are suitable for low gain ship-borne antennas. Also, a performance evaluation of the stabilizers is discussed using a statistical analysis of ship motion characteristics. Furthermore, fading characteristics of received signal strength due to antenna off-beam fluctuation and sea surface random reflection are experimentally evaluated.

  8. Satellite Beam Handover Strategy to Improve Return Link Resource Utilization

    Directory of Open Access Journals (Sweden)

    Jinyoung Jang

    2011-11-01

    Full Text Available Mobile communication on the multi-beam satellite communication has attracted attention, since Digital Video Broadcasting – Return Channel Satellite (DVB-RCS has been successively implemented. In general, multi beam satellite employs uniform allocation of RF power and bandwidth to multi beams, since it is hard to predict the distribution of traffic requests and the arrival rate of new connection. This makes it difficult to satisfy the traffic requests in a beam. Thus, when an unpredictable event, such as a disaster, regional warfare and deteriorating weather conditions, occur in a special spot beam, many more terminals will require access to a special beam channel. This causes the special beam channel to be saturated, while adjacent beam channel resources are available. Thus, we propose a novel handover strategy to improve satellite return link resource utilization using load balancing handover. Simulation results shows the proposed handover algorithm outperforms conventional handover algorithms in terms of new connection block probability, handover block probability, return link resource utilization and capacity request block rate.

  9. Using multi-beam echo sounder backscatter data for sediment classification in very shallow water environments

    NARCIS (Netherlands)

    Amiri-Simkooei, A.R.; Snellen, M.; Simons, D.G.

    2009-01-01

    In a recent work described in Ref. [1], an angle-independent methodology was developed to use the multi-beam echo sounder backscatter (MBES) data for the seabed sediment classification. The method employs the backscatter data at a certain angle to obtain the number of sediment classes and to discrim

  10. An efficient method for reducing the sound speed induced errors in multibeam echosounder bathymetric measurements

    NARCIS (Netherlands)

    Snellen, M.; Siemes, K.; Simons, D.G.

    2009-01-01

    Nowadays extensive use is made of multibeam echosounders (MBES) for mapping the bathymetry of sea- and river-floors. The MBES is capable of covering large areas in limited time by emitting an acoustic pulse along a wide swathe perpendicular to the sailing direction. The angle and the corresponding t

  11. Morphology of a coral bank, western continental shelf of India: A multibeam study

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, P.S.; Kodagali, V.N.; Ramprasad, T.; Nair, R.R.

    Morphology of a living coral bank (Gaveshani Bank) is described using multibeam swath bathymetric survey system Hydrosweep. The bank has a height of 42 m, length of 2 km and a maximum width of 1.66 km, with steep flanks and flat top. It has a north...

  12. 2006 Multibeam Mapping of cross-shelf corridor, North of Madison-Swanson - Florida

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This disk or set of disks contain high-resolution multibeam and backscatter maps of an area North of Madison-Swanson (29.1667N, 85.6667W), in the West-Florida shelf,...

  13. Oculina Banks Bathymetry 2002 from Multi-beam and Sidescan Sonar Surveys (NODC Accession 0090252)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data are the result of a multi-beam echosounder survey conducted in the OHAPC by the M/V Liberty Star in October 2002. Two forms of data are available: 1)...

  14. Improving Multibeam Data Quality Across the U.S. Academic Research Fleet

    Science.gov (United States)

    Johnson, P. D.; Beaudoin, J.; Ferrini, V.

    2012-12-01

    The Multibeam Advisory Committee (MAC) is an NSF funded project with the goal of improving the quality of multibeam across the U.S. academic research fleet. There are many facets to the Committee's plan to reach this goal, one of which is to have a team of multibeam specialists visiting vessels in the fleet. During their ship visits, the MAC's Quality Assurance Team (QAT) deploys software tools, disseminates "best practice" documentation, assesses the state of the system as a whole and does everything they can to help ship operators better understand and operate their multibeam systems. A big part of these ship visits is simply outreach: we want to let the operators know that they have access to help if they need it. In addition to developing working relationships with the operating institutions, the MAC seeks to reach out to the end user: the scientific community that uses these facilities to further their research. By presenting the MAC and QAT concepts to the community, we hope to raise awareness of our efforts, introduce the software tools and best-practice documentation that we are deploying and also solicit feedback on what future directions the MAC should focus.

  15. Multibeam Bathymetric Gridded Data for selected U.S. locations in the Pacific since 2003

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Gridded bathymetry for selected U.S. locations in the Pacific. The netCDF and Arc ASCII grids include multibeam bathymetry from the Simrad EM300, Simrad EM3002D, and...

  16. Fabrication and Characterization of Three Dimensional Photonic Crystals Generated by Multibeam Interference Lithography

    Science.gov (United States)

    Chen, Ying-Chieh

    2009-01-01

    Multibeam interference lithography is investigated as a manufacturing technique for three-dimensional photonic crystal templates. In this research, optimization of the optical setup and the photoresist initiation system leads to a significant improvement of the optical quality of the crystal, as characterized by normal incidence optical…

  17. Assessment of a multibeam Fizeau wedge interferometer for Doppler wind lidar.

    Science.gov (United States)

    McKay, Jack A

    2002-03-20

    The Fabry-Perot interferometer is the standard instrument for the direct detection Doppler lidar measurement of atmospheric wind speeds. The multibeam Fizeau wedge has some practical advantages over the Fabry-Perot, such as the linear fringe pattern, and is evaluated for this application. The optimal Fizeau must have a resolving power of 10(6) or more. As the multibeam Fizeau wedge is pushed to such high resolving power, the interference fringes of the device become complicated by asymmetry and secondary maxima. A simple condition for the interferometer plate reflectance, optical gap, and wedge angle reveals whether a set of parameters will yield simple, Airy-like fringes or complex Fizeau fringes. Tilting of the Fizeau wedge improves the fringe shape and permits an extension of the regime of Airy-like fringes to higher resolving power. Sufficient resolving power for the wind lidar application is shown to be possible with a large-gap, low-finesse multibeam Fizeau wedge. Liabilities of the multibeam Fizeau wedge in the wind lidar application include a smaller acceptance solid angle and calibration sensitivity to localized deviations of the plates from the ideal.

  18. Advanced Concurrent-Multiband, Multibeam, Aperture-Synthesis with Intelligent Processing for Urban Operation Sensing

    Science.gov (United States)

    2012-04-09

    Final 3. DATES COVERED (From - To) Feb. 1, 2009-Nov. 30, 2011 4. TITLE AND SUBTITLE Advanced Concurrent-Multiband, Multibeam , Aperture-Synthesis 5a...around 1.5 λ apart. This frequency separation is close to the difference between electro- 11 optic (EO) and infrared sensors which are considered

  19. Fabrication and Characterization of Three Dimensional Photonic Crystals Generated by Multibeam Interference Lithography

    Science.gov (United States)

    Chen, Ying-Chieh

    2009-01-01

    Multibeam interference lithography is investigated as a manufacturing technique for three-dimensional photonic crystal templates. In this research, optimization of the optical setup and the photoresist initiation system leads to a significant improvement of the optical quality of the crystal, as characterized by normal incidence optical…

  20. Gridded multibeam bathymetry and SHOALS LIDAR bathymetry of Penguin Bank, Hawaii, USA

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Gridded bathymetry (5 m cell size) of Penguin Bank, Hawaii, USA. The netCDF grid and ArcGIS ASCII file include multibeam bathymetry from the Simrad EM3002d, and...

  1. Integrated Multibeam and LIDAR Bathymetry Data Offshore of New London and Niantic, Connecticut

    Science.gov (United States)

    Poppe, L.J.; Danforth, W.W.; McMullen, K.Y.; Parker, Castle E.; Lewit, P.G.; Doran, E.F.

    2010-01-01

    Nearshore areas within Long Island Sound are of great interest to the Connecticut and New York research and resource management communities because of their ecological, recreational, and commercial importance. Although advances in multibeam echosounder technology permit the construction of high-resolution representations of sea-floor topography in deeper waters, limitations inherent in collecting fixed-angle multibeam data make using this technology in shallower waters (less than 10 meters deep) difficult and expensive. These limitations have often resulted in data gaps between areas for which multibeam bathymetric datasets are available and the adjacent shoreline. To address this problem, the geospatial data sets released in this report seamlessly integrate complete-coverage multibeam bathymetric data acquired off New London and Niantic Bay, Connecticut, with hydrographic Light Detection and Ranging (LIDAR) data acquired along the nearshore. The result is a more continuous sea floor representation and a much smaller gap between the digital bathymetric data and the shoreline than previously available. These data sets are provided online and on CD-ROM in Environmental Systems Research Institute (ESRI) raster-grid and GeoTIFF formats in order to facilitate access, compatibility, and utility.

  2. Satellite mobile data service for Canada

    Science.gov (United States)

    Egan, Glenn R.; Sward, David J.

    A commercial mobile satellite system which is to be constructed and operated in Canada is examined. This is done in two phases. First, mobile data services was introduced. Hub equipment and 3000 mobile data terminals were supplied. Over the satellite tests were performed. The mobile data service provides full two way digital messaging automatic vehicle location and fleet management services. The second phase is to construct, launch and make operational the MSAT satellite and associated network control facilities. The implementation is examined of the mobile data service in Canada, including the technical description. Marketing and applications are also examined.

  3. Arbitrary multibeam laser scanning and trapping by use of a spatial light modulator and manual scripting interface

    Science.gov (United States)

    Xun, Xiaodong; Chang, Xiaoguang; Cho, Doo Jin; Cohn, Robert W.

    2004-10-01

    A multi-beam, variable footprint, laser beam steering and shaping system is described and used with a microscope to demonstrate multi-particle laser trapping. It is built around a computer-interfaced 512x512 pixel analog phase-only spatial light modulator (SLM) and a 1 W, 1064 nm wavelength laser. Hand sketches on paper made with a digital pen are used to prescribe the footprints, velocities and trajectories of multiple, independently-controlled diffracted spots. Continuous scanning is approximated by automatically designing a sequence of phase-patterns that are run through and diffracted by the SLM. Very complex scanning sequences of dozens of independently controlled spots can be quickly designed and run. The number of beams that we can trap with is necessarily limited due to the low throughput (~23 mW) of the IR light through the microscope optics. Among the trapping experiments done with the system a triangular shaped vortex ring tends to stop single particles at the apexes of the triangle. However, collision with a second particle pushes the first particle past the apex and sets it into motion, leaving the second particle stopped until collision with a third particle. The discrete motion conditioned on collisions is suggestive of a queuing process or a Markov chain.

  4. Sea-Floor Images and Data from Multibeam Surveys in San Francisco Bay, Southern California, Hawaii, the Gulf of Mexico, and Lake Tahoe, California-Nevada

    Science.gov (United States)

    Dartnell, Peter; Gardiner, James V.

    1999-01-01

    Accurate base maps are a prerequisite for any geologic study, regardless of the objectives. Land-based studies commonly utilize aerial photographs, USGS 7.5-minute quadrangle maps, and satellite images as base maps. Until now, studies that involve the ocean floor have been at a disadvantage due to an almost complete lack of accurate marine base maps. Many base maps of the sea floor have been constructed over the past century but with a wide range in navigational and depth accuracies. Only in the past few years has marine surveying technology advanced far enough to produce navigational accuracy of 1 meter and depth resolutions of 50 centimeters. The Pacific Seafloor Mapping Project of the U.S. Geological Survey's, Western Coastal and Marine Geology Program, Menlo Park, California, U.S.A., in cooperation with the Ocean Mapping Group, University of New Brunswick, Fredericton, Canada, is using this new technology to systematically map the ocean floor and lakes. This type of marine surveying, called multibeam surveying, collects high-resolution bathymetric and backscatter data that can be used for various base maps, GIS coverages, and scientific visualization methods. This is an interactive CD-ROM that contains images, movies, and data of all the surveys the Pacific Seafloor Mapping Project has completed up to January 1999. The images and movies on this CD-ROM, such as shaded relief of the bathymetry, backscatter, oblique views, 3-D views, and QuickTime movies help the viewer to visualize the multibeam data. This CD-ROM also contains ARC/INFO export (.e00) files and full-resolution TIFF images of all the survey sites that can be downloaded and used in many GIS packages.

  5. Earth Observation Satellites Scheduling Based on Decomposition Optimization Algorithm

    Directory of Open Access Journals (Sweden)

    Feng Yao

    2010-11-01

    Full Text Available A decomposition-based optimization algorithm was proposed for solving Earth Observation Satellites scheduling problem. The problem was decomposed into task assignment main problem and single satellite scheduling sub-problem. In task assignment phase, the tasks were allocated to the satellites, and each satellite would schedule the task respectively in single satellite scheduling phase. We adopted an adaptive ant colony optimization algorithm to search the optimal task assignment scheme. Adaptive parameter adjusting strategy and pheromone trail smoothing strategy were introduced to balance the exploration and the exploitation of search process. A heuristic algorithm and a very fast simulated annealing algorithm were proposed to solve the single satellite scheduling problem. The task assignment scheme was valued by integrating the observation scheduling result of multiple satellites. The result was responded to the ant colony optimization algorithm, which can guide the search process of ant colony optimization. Computation results showed that the approach was effective to the satellites observation scheduling problem.

  6. 基于卫星DOR信号的VLBI相时延解算方法研究%Method of Calculating VLBI Phase Delay Based on DOR Signal of a Satellite

    Institute of Scientific and Technical Information of China (English)

    陈冠磊; 郑鑫; 陈明; 刘庆会; 戴志强; 吴亚军; 赵融冰

    2012-01-01

    VLBI技术是深空探测中主要的测角手段,其对与视线垂直方向上卫星的轨道和位置变化有很高的灵敏度.基于DOR信号的VLBI观测量一般是群时延,其精度一般为纳秒量级,在约2000 km的基线长度上,月球探测器的位置测量误差达近百米,对深空探测器来说位置测量误差会更大.为了提高卫星测定轨测定位精度,研究了含微小偏倚量的VLBI相时延的解算算法,并利用嫦娥—号△DOR观测数据对连续观测和间断观测时的算法进行了验证.结果表明:两种观测模式下皆可行.经过比较,相时延的随机误差大幅降低.%In deep space exploration, the VLBI technique is a precise method for the angular measurement, which can give the plane-of-sky position information. The group delay of DOR signal can usually be obtained with an accuracy of nanosecond in the VLBI observation. The accuracy of group delay can bring an orbital error of lunar probe about a hundred meters for a baseline of about 2000 kilometers. Especially in the further deep space exploration, the orbital error will be much larger. A method to calculate the small biased phase delay of VLBI is proposed in this paper in order to improve the accuracy of the orbit and position determination. The small biased phase delay is acquired by using the phase delay with ambiguity approaching the middle of bandwidth synthesis group delay of DOR signal. The method both in continuous and discontinuous observation is feasible, proved by processing the data from CE-2 satellite A DOR experiments. The relationship between the group delay and phase delay is discussed. Both of the closure group delay and the closure phase delay of three baselines of SH-BJ, SH-UR and BJ-UR are calculated, and the errors of them are analyzed. The phases of the carrier and the DOR tones are compared to prove the validity of the method. The phase delay's error, especially the random error, can be reduced. The system error will be

  7. Multibeam collection for MV0903: Multibeam data collected aboard Melville from 2009-02-27 to 2009-03-21, departing from Manila, Philippines and returning to Manila, Philippines

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  8. Multibeam collection for HLY14TC: Multibeam data collected aboard Healy from 2014-06-25 to 2014-07-03, departing from Dutch Harbor, AK and returning to Dutch Harbor, AK

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  9. Multibeam collection for AT23: Multibeam data collected aboard Atlantis from 2012-10-22 to 2012-10-26, departing from Woods Hole, MA and returning to Woods Hole, MA

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  10. Multibeam collection for KM0609: Multibeam data collected aboard Kilo Moana from 2006-03-20 to 2006-03-21, departing from Honolulu, HI and returning to Honolulu, HI

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  11. Multibeam collection for KM1122: Multibeam data collected aboard Kilo Moana from 2011-08-10 to 2011-08-17, departing from Honolulu, HI and returning to Honolulu, HI

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  12. Multibeam collection for MGLN02MV: Multibeam data collected aboard Melville from 2006-04-18 to 2006-05-13, departing from Guam and returning to Yokohama, Japan

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  13. Multibeam collection for COOK21MV: Multibeam data collected aboard Melville from 2002-03-24 to 2002-04-12, departing from Apia, Western Samoa and returning to Majuro, Marshall Islands

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  14. Multibeam collection for NBP0501: Multibeam data collected aboard Nathaniel B. Palmer from 2005-01-28 to 2005-02-13, departing from McMurdo Station, Antarctica and returning to Lyttelton, New Zealand

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  15. Multibeam collection for NBP0209: Multibeam data collected aboard Nathaniel B. Palmer from 2002-12-11 to 2002-12-29, departing from Lyttelton, New Zealand and returning to McMurdo Station, Antarctica

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  16. Multibeam collection for NBP0207: Multibeam data collected aboard Nathaniel B. Palmer from 2002-11-11 to 2002-12-03, departing from Port Hueneme, CA and returning to Lyttelton, New Zealand

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  17. Multibeam collection for EW9709: Multibeam data collected aboard Maurice Ewing from 1997-12-12 to 1998-01-17, departing from San Diego, CA and returning to Honolulu, HI

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  18. Multibeam collection for MGLN11MV: Multibeam data collected aboard Melville from 2006-11-15 to 2006-12-17, departing from Honolulu, HI and returning to Brisbane, Australia

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  19. Multibeam collection for FK140307: Multibeam data collected aboard Falkor from 2014-03-07 to 2014-04-11, departing from Honolulu, HI and returning to Honolulu, HI

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  20. Multibeam collection for PLUM02WT: Multibeam data collected aboard Thomas Washington from 1990-01-17 to 1990-02-12, departing from Galapagos Islands, Ecuador and returning to Galapagos Islands, Ecuador

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  1. Multibeam collection for MV1209: Multibeam data collected aboard Melville from 2012-06-30 to 2012-07-10, departing from San Diego, CA and returning to San Diego, CA

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  2. Multibeam collection for KNOX21RR: Multibeam data collected aboard Roger Revelle from 2008-11-11 to 2008-12-01, departing from Tampa, FL and returning to Montevideo, Uruguay

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  3. Multibeam collection for NBP1103: Multibeam data collected aboard Nathaniel B. Palmer from 2011-05-09 to 2011-06-11, departing from Punta Arenas, Chile and returning to Punta Arenas, Chile

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  4. Multibeam collection for Tecfluc: Multibeam data collected aboard Ocean Alert from 1998-05-23 to 1998-05-26, departing from Unknown Port and returning to Unknown Port

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  5. Multibeam collection for MV0904: Multibeam data collected aboard Melville from 2009-03-23 to 2009-03-28, departing from Manila, Philippines and returning to Kao-hsiung, Taiwan

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  6. Multibeam collection for AT03L35: Multibeam data collected aboard Atlantis from 1999-06-20 to 1999-07-13, departing from San Diego, CA and returning to Astoria, OR

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  7. Multibeam collection for RC2711: Multibeam data collected aboard Robert Conrad from 1986-12-03 to 1987-01-02, departing from Cape Town, South Africa and returning to Rio de Janeiro, Brazil

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  8. Multibeam collection for KM0623: Multibeam data collected aboard Kilo Moana from 2006-07-25 to 2006-07-27, departing from Honolulu, HI and returning to Honolulu, HI

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  9. Multibeam collection for MRTN04WT: Multibeam data collected aboard Thomas Washington from 1984-07-13 to 1984-08-08, departing from Kodiak, AK and returning to Honolulu, HI

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  10. Multibeam collection for AT11L03: Multibeam data collected aboard Atlantis from 2003-10-31 to 2003-11-24, departing from Panama City, Panama and returning to Manzanillo, Mexico

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  11. Multibeam collection for MGLN29MV: Multibeam data collected aboard Melville from 2007-11-27 to 2007-11-29, departing from Kao-hsiung, Taiwan and returning to Manila, Philippines

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  12. Multibeam collection for B00306: Multibeam data collected aboard Whiting from 1992-05-29 to 1992-07-16, departing from Norfolk, VA and returning to Norfolk, VA

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  13. Multibeam collection for TN230: Multibeam data collected aboard Thomas G. Thompson from 2009-03-02 to 2009-03-12, departing from Lyttelton, New Zealand and returning to Auckland, New Zealand

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  14. Multibeam collection for KN166L08: Multibeam data collected aboard Knorr from 2002-04-17 to 2002-05-02, departing from Bridgetown, Barbados and returning to Guadeloupe

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  15. Multibeam collection for DRFT14RR: Multibeam data collected aboard Roger Revelle from 2002-04-24 to 2002-05-03, departing from Honolulu, HI and returning to Honolulu, HI

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  16. Multibeam collection for FK151221: Multibeam data collected aboard Falkor from 2015-12-21 to 2016-01-05, departing from Apra, Guam and returning to Honolulu, HI

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  17. Multibeam collection for B00028: Multibeam data collected aboard Surveyor from 1985-09-05 to 1985-09-05, departing from Seattle, WA and returning to Seattle, WA

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  18. Multibeam collection for RR1413: Multibeam data collected aboard Roger Revelle from 2014-11-29 to 2014-12-21, departing from Apra, Guam and returning to Apra, Guam

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  19. Multibeam collection for HLY07TB: Multibeam data collected aboard Healy from 2007-03-09 to 2007-03-16, departing from Seattle, WA and returning to Seattle, WA

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  20. Multibeam collection for KM1018: Multibeam data collected aboard Kilo Moana from 2010-09-16 to 2010-09-23, departing from Honolulu, HI and returning to Honolulu, HI

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  1. Multibeam collection for KM0511: Multibeam data collected aboard Kilo Moana from 2005-05-28 to 2005-05-30, departing from Honolulu, HI and returning to Honolulu, HI

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  2. Multibeam collection for EX1202Leg3: Multibeam data collected aboard Okeanos Explorer from 2012-04-12 to 2012-04-29, departing from Pascagoula, MS and returning to Galveston, TX

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  3. Multibeam collection for deepslope2007: Multibeam data collected aboard Ronald Brown from 2007-06-04 to 2007-07-06, departing from Fort Lauderdale, FL and returning to Galveston, TX

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  4. Multibeam collection for NEMO04MV: Multibeam data collected aboard Melville from 2000-06-12 to 2000-06-28, departing from Puerto Caldera, Costa Rica and returning to San Diego, CA

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  5. Multibeam collection for HLY1101: Multibeam data collected aboard Healy from 2011-06-25 to 2011-07-29, departing from Dutch Harbor, AK and returning to Seward, AK

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  6. Multibeam collection for RR1007: Multibeam data collected aboard Roger Revelle from 2010-06-01 to 2010-06-11, departing from Kao-hsiung, Taiwan and returning to Kao-hsiung, Taiwan

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  7. Multibeam collection for B00008: Multibeam data collected aboard Surveyor from 1984-11-05 to 1984-11-09, departing from Seattle, WA and returning to Seattle, WA

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  8. Multibeam collection for KNOX15RR: Multibeam data collected aboard Roger Revelle from 2008-03-20 to 2008-04-17, departing from Cape Town, South Africa and returning to Port Everglades, FL

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  9. Multibeam collection for MV1214: Multibeam data collected aboard Melville from 2012-10-26 to 2012-10-31, departing from San Diego, CA and returning to San Diego, CA

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  10. Multibeam collection for RR1511: Multibeam data collected aboard Roger Revelle from 2015-08-04 to 2015-08-15, departing from Colombo, Sri Lanka and returning to Colombo, Sri Lanka

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  11. Multibeam collection for KNOX04RR: Multibeam data collected aboard Roger Revelle from 2007-03-22 to 2007-05-02, departing from Fremantle, Australia and returning to Phuket, Thailand

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  12. Multibeam collection for BAS_GAP: Multibeam data collected aboard James Clark Ross from 2003-06-13 to 2003-06-14, departing from Unknown Port and returning to Unknown Port

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  13. Multibeam collection for KM0818: Multibeam data collected aboard Kilo Moana from 2008-09-08 to 2008-09-22, departing from Port Hueneme, CA and returning to Port Hueneme, CA

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  14. Multibeam collection for B00115: Multibeam data collected aboard Davidson from 1987-08-12 to 1987-10-09, departing from Seattle, WA and returning to Seattle, WA

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  15. Multibeam collection for KN205: Multibeam data collected aboard Knorr from 2012-02-22 to 2012-03-17, departing from Woods Hole, MA and returning to Woods Hole, MA

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  16. Multibeam collection for TN269: Multibeam data collected aboard Thomas G. Thompson from 2011-09-09 to 2011-10-04, departing from Seattle, WA and returning to Seattle, WA

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  17. Multibeam collection for EW9402: Multibeam data collected aboard Maurice Ewing from 1994-02-17 to 1994-03-21, departing from Salvador de Bahia, Brazil and returning to Cayenne, French Guiana

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  18. Multibeam collection for AT11L01: Multibeam data collected aboard Atlantis from 2003-10-05 to 2003-10-20, departing from Woods Hole, MA and returning to Galveston, TX

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  19. Multibeam collection for Puna-rid: Multibeam data collected aboard Ocean Alert from 1998-03-01 to 1998-03-03, departing from Unknown Port and returning to Unknown Port

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  20. Multibeam collection for NBP0802: Multibeam data collected aboard Nathaniel B. Palmer from 2008-01-30 to 2008-02-19, departing from McMurdo Station, Antarctica and returning to McMurdo Station, Antarctica

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  1. Multibeam collection for NBP9601: Multibeam data collected aboard Nathaniel B. Palmer from 1996-01-28 to 1996-02-18, departing from McMurdo Station, Antarctica and returning to McMurdo Station, Antarctica

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  2. Multibeam collection for KM0202: Multibeam data collected aboard Kilo Moana from 2002-08-14 to 2002-09-03, departing from Balboa, Panama and returning to Honolulu, HI

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  3. Multibeam collection for SKQ201502T: Multibeam data collected aboard Sikuliaq from 2015-02-12 to 2015-02-18, departing from Ketchikan, AK and returning to Juneau, AK

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  4. Multibeam collection for EX0907: Multibeam data collected aboard Okeanos Explorer from 2009-07-14 to 2009-07-23, departing from Astoria, OR and returning to San Francisco, CA

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  5. Multibeam collection for NBP0607C: Multibeam data collected aboard Nathaniel B. Palmer from 2006-10-10 to 2006-10-23, departing from Lyttelton, New Zealand and returning to Lyttelton, New Zealand

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  6. Multibeam collection for KN201: Multibeam data collected aboard Knorr from 2011-06-24 to 2011-07-17, departing from Woods Hole, MA and returning to Woods Hole, MA

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  7. Multibeam collection for EX1104: Multibeam data collected aboard Okeanos Explorer from 2011-08-02 to 2011-08-18, departing from Rousseau, Panama and returning to Key West, FL

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  8. Multibeam collection for EX1103: Multibeam data collected aboard Okeanos Explorer from 2011-06-11 to 2011-07-28, departing from San Diego, CA and returning to Rousseau, Panama

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  9. Multibeam collection for FK005C: Multibeam data collected aboard Falkor from 2012-10-08 to 2012-10-20, departing from Corpus Christi, TX and returning to Corpus Christi, TX

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  10. Multibeam collection for FK006A: Multibeam data collected aboard Falkor from 2012-10-28 to 2012-11-01, departing from Corpus Christi, TX and returning to Pascagoula, MS

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  11. Multibeam collection for NEMO02MV: Multibeam data collected aboard Melville from 2000-03-24 to 2000-05-10, departing from Manzanillo, Mexico and returning to Manzanillo, Mexico

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  12. Multibeam collection for B00091: Multibeam data collected aboard Discoverer from 1986-11-11 to 1986-11-17, departing from Seattle, WA and returning to Seattle, WA

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  13. Multibeam collection for MV1313: Multibeam data collected aboard Melville from 2013-10-03 to 2013-10-27, departing from San Diego, CA and returning to San Diego, CA

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  14. Multibeam collection for AII8L11: Multibeam data collected aboard Atlantis II from 1987-02-17 to 1987-02-22, departing from Hilo, HI and returning to Honolulu, HI

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  15. Multibeam collection for B00267: Multibeam data collected aboard Whiting from 1991-04-29 to 1991-05-10, departing from Norfolk, VA and returning to Norfolk, VA

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  16. Multibeam collection for CB14_02: Multibeam data collected aboard Cosantoir Bradan from 2014-05-29 to 2014-06-27, departing from Killybegs, Ireland and returning to Killybegs, Ireland

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  17. Multibeam collection for AT18-02: Multibeam data collected aboard Atlantis from 2010-11-08 to 2010-12-03, departing from Galveston, TX and returning to Gulfport, MS

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  18. Multibeam collection for KM1013: Multibeam data collected aboard Kilo Moana from 2010-07-13 to 2010-07-23, departing from Honolulu, HI and returning to Honolulu, HI

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  19. Multibeam collection for CV06_01: Multibeam data collected aboard Celtic Voyager from 2006-05-24 to 2006-05-29, departing from Unknown Port and returning to Unknown Port

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  20. Multibeam collection for KM0512: Multibeam data collected aboard Kilo Moana from 2005-06-02 to 2005-06-10, departing from Honolulu, HI and returning to Honolulu, HI

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  1. Multibeam collection for KN159L5: Multibeam data collected aboard Knorr from 1998-10-06 to 1998-11-04, departing from Rio de Janeiro, Brazil and returning to Rio de Janeiro, Brazil

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  2. Multibeam collection for KM1410: Multibeam data collected aboard Kilo Moana from 2014-04-09 to 2014-04-13, departing from Honolulu, HI and returning to Honolulu, HI

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  3. Multibeam collection for LAN-92: Multibeam data collected aboard Laney Chouest from 1992-08-18 to 1992-10-27, departing from Unknown Port and returning to Unknown Port

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  4. Multibeam collection for EW9415: Multibeam data collected aboard Maurice Ewing from 1994-10-13 to 1994-10-21, departing from Long Beach, CA and returning to San Diego, CA

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  5. Multibeam collection for GENE03RR: Multibeam data collected aboard Roger Revelle from 1997-02-23 to 1997-04-05, departing from Punta Arenas, Chile and returning to Callao, Peru

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  6. Multibeam collection for HLY13TC: Multibeam data collected aboard Healy from 2013-09-08 to 2013-09-21, departing from Barrow, AK and returning to Seward, AK

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  7. Multibeam collection for FK007: Multibeam data collected aboard Falkor from 2013-03-09 to 2013-03-29, departing from Miami, FL and returning to St. Petersburg, FL

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  8. Multibeam collection for REVT01RR: Multibeam data collected aboard Roger Revelle from 1996-09-27 to 1996-10-03, departing from San Diego, CA and returning to San Diego, CA

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  9. Multibeam collection for KN162L17: Multibeam data collected aboard Knorr from 2001-06-01 to 2001-06-10, departing from Istanbul, Turkey and returning to Istanbul, Turkey

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  10. Multibeam collection for MRTN09WT: Multibeam data collected aboard Thomas Washington from 1984-11-18 to 1984-12-11, departing from Montevideo, Uruguay and returning to Rio de Janeiro, Brazil

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  11. Multibeam collection for KN176L04: Multibeam data collected aboard Knorr from 2004-03-16 to 2004-04-10, departing from Barbados and returning to Woods Hole, MA

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  12. Multibeam collection for NBP9908: Multibeam data collected aboard Nathaniel B. Palmer from 1999-08-18 to 1999-09-05, departing from Chile and returning to Lyttelton, New Zealand

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  13. Multibeam collection for KN165: Multibeam data collected aboard Knorr from 2001-11-06 to 2001-11-10, departing from Woods Hole, MA and returning to Woods Hole, MA

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  14. Multibeam collection for AT22: Multibeam data collected aboard Atlantis from 2012-08-15 to 2012-09-10, departing from Woods Hole, MA and returning to Boston, MA

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  15. Multibeam collection for RR1509: Multibeam data collected aboard Roger Revelle from 2015-06-20 to 2015-06-30, departing from Napier, New Zealand and returning to Napier, New Zealand

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  16. Multibeam collection for NBP1004: Multibeam data collected aboard Nathaniel B. Palmer from 2010-10-23 to 2010-11-15, departing from Punta Arenas, Chile and returning to Punta Arenas, Chile

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  17. Multibeam collection for NF0804_usvi: Multibeam data collected aboard Nancy Foster from 2008-02-24 to 2008-03-08, departing from San Juan, Puerto Rico and returning to San Juan, Puerto Rico

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  18. Multibeam collection for KNOX10RR: Multibeam data collected aboard Roger Revelle from 2007-10-22 to 2007-11-04, departing from Mormugao, India and returning to Mahe, Seychelles

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  19. Multibeam collection for RR1404: Multibeam data collected aboard Roger Revelle from 2014-05-29 to 2014-06-14, departing from Chi-Lung, Taiwan and returning to Chennai, India

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  20. Multibeam collection for M29L3: Multibeam data collected aboard Meteor from 1994-08-13 to 1994-09-03, departing from Rio de Janeiro, Brazil and returning to Las Palmas, Spain

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  1. Multibeam collection for SO83: Multibeam data collected aboard Sonne from 1992-12-02 to 1992-12-27, departing from Bremerhaven, Germany and returning to Las Palmas, Spain

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  2. Multibeam collection for KN151L4: Multibeam data collected aboard Knorr from 1997-08-15 to 1997-09-02, departing from Port of Spain, Trinidad and Tobago and returning to Woods Hole, MA

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  3. Multibeam collection for KN151L3: Multibeam data collected aboard Knorr from 1997-07-17 to 1997-08-09, departing from Halifax, Canada and returning to Port of Spain, Trinidad and Tobago

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  4. Multibeam collection for RC2912: Multibeam data collected aboard Robert Conrad from 1988-12-02 to 1989-01-07, departing from Cadiz, Spain and returning to Azores

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  5. Multibeam collection for KN173L02: Multibeam data collected aboard Knorr from 2003-10-23 to 2003-11-14, departing from Port of Spain, Trinidad and Tobago and returning to Woods Hole, MA

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  6. Multibeam collection for KN162L19: Multibeam data collected aboard Knorr from 2001-06-25 to 2001-07-22, departing from Las Palmas, Spain and returning to Bridgetown, Barbados

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  7. Multibeam collection for MGL1307: Multibeam data collected aboard Marcus G. Langseth from 2013-05-30 to 2013-08-02, departing from Vigo, Spain and returning to Vigo, Spain

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  8. Multibeam collection for VANC13MV: Multibeam data collected aboard Melville from 2003-08-21 to 2003-08-26, departing from Cairns, Australia and returning to Port Moresby, Papua New Guinea

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  9. Multibeam collection for KM0909: Multibeam data collected aboard Kilo Moana from 2009-03-20 to 2009-04-09, departing from Kao-hsiung, Taiwan and returning to Kao-hsiung, Taiwan

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  10. Multibeam collection for MGL0903: Multibeam data collected aboard Marcus G. Langseth from 2009-01-24 to 2009-03-08, departing from Nuku'alofa, Tonga and returning to Suva, Fiji

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  11. Multibeam collection for RR0912: Multibeam data collected aboard Roger Revelle from 2009-09-19 to 2009-10-09, departing from Chi-Lung, Taiwan and returning to Kao-hsiung, Taiwan

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  12. Multibeam collection for RR0915: Multibeam data collected aboard Roger Revelle from 2009-11-21 to 2009-12-05, departing from Nuku'alofa, Tonga and returning to Suva, Fiji

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  13. Multibeam collection for RR1004: Multibeam data collected aboard Roger Revelle from 2010-03-21 to 2010-04-01, departing from Kao-hsiung, Taiwan and returning to Kao-hsiung, Taiwan

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  14. Multibeam collection for TN235: Multibeam data collected aboard Thomas G. Thompson from 2009-05-16 to 2009-06-08, departing from Apia, Samoa and returning to Nuku'alofa, Tonga

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  15. Multibeam collection for KN209-01: Multibeam data collected aboard Knorr from 2012-09-06 to 2012-10-09, departing from Woods Hole, MA and returning to Ponta Delgada, Azores

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  16. Multibeam collection for RR1016: Multibeam data collected aboard Roger Revelle from 2010-11-06 to 2010-11-24, departing from Kao-hsiung, Taiwan and returning to Kao-hsiung, Taiwan

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  17. Multibeam collection for RR0916: Multibeam data collected aboard Roger Revelle from 2009-12-09 to 2009-12-15, departing from Suva, Fiji and returning to Nuku'alofa, Tonga

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  18. Multibeam collection for AT15-45: Multibeam data collected aboard Atlantis from 2009-03-09 to 2009-03-23, departing from Puntarenas, Costa Rica and returning to San Diego, CA

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  19. Multibeam collection for AHI-07-03: Multibeam data collected aboard Ahi from 2007-05-23 to 2007-06-09, departing from Saipan, CNMI and returning to Saipan, CNMI

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  20. Multibeam collection for KN164L01: Multibeam data collected aboard Knorr from 2001-10-05 to 2001-10-08, departing from Woods Hole, MA and returning to Charleston, SC

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  1. Multibeam collection for RR0904: Multibeam data collected aboard Roger Revelle from 2009-05-20 to 2009-06-23, departing from Fremantle, Australia and returning to Port Darwin, Australia

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  2. Multibeam collection for MGLN12MV: Multibeam data collected aboard Melville from 2007-02-03 to 2007-02-08, departing from Brisbane, Australia and returning to Wellington, New Zealand

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  3. Multibeam collection for RR1501: Multibeam data collected aboard Roger Revelle from 2015-01-09 to 2015-02-03, departing from Hobart, Australia and returning to Hobart, Australia

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  4. Multibeam collection for KM0702: Multibeam data collected aboard Kilo Moana from 2007-02-13 to 2007-03-10, departing from Brisbane, Australia and returning to Townsville, Australia

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  5. Multibeam collection for SOJN08MV: Multibeam data collected aboard Melville from 1997-05-14 to 1997-05-26, departing from Melbourne, Australia and returning to Papeete, French Polynesia

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  6. Multibeam collection for VANC12MV: Multibeam data collected aboard Melville from 2003-08-08 to 2003-08-16, departing from Darwin, Australia and returning to Cairns, Australia

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  7. Multibeam collection for EW9912: Multibeam data collected aboard Maurice Ewing from 1999-10-27 to 1999-11-28, departing from Townsville, Australia and returning to Townsville, Australia

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  8. Multibeam collection for MV0911: Multibeam data collected aboard Melville from 2009-11-21 to 2010-01-02, departing from Brisbane, Australia and returning to Papeete, French Polynesia

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  9. Multibeam collection for RB0605AMMA: Multibeam data collected aboard Ronald Brown from 2006-05-27 to 2006-06-18, departing from San Juan, Puerto Rico and returning to Recife, Brazil

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  10. Multibeam collection for RR1002: Multibeam data collected aboard Roger Revelle from 2010-01-26 to 2010-02-18, departing from Wellington, New Zealand and returning to Wellington, New Zealand

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  11. Multibeam collection for PASC05WT: Multibeam data collected aboard Thomas Washington from 1983-05-04 to 1983-05-26, departing from Callao, Peru and returning to San Diego, CA

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  12. Multibeam collection for PANR02MV: Multibeam data collected aboard Melville from 1997-12-14 to 1997-12-29, departing from Acapulco, Mexico and returning to Callao, Peru

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  13. Multibeam collection for RB0307: Multibeam data collected aboard Ronald Brown from 2003-09-08 to 2003-10-02, departing from St. Petersburg, FL and returning to Gulfport, MS

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  14. Multibeam collection for PLUM08WT: Multibeam data collected aboard Thomas Washington from 1990-06-29 to 1990-07-09, departing from La Guaira, Venezuela and returning to Manzanillo, Mexico

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  15. Multibeam collection for KN200-06: Multibeam data collected aboard Knorr from 2011-05-15 to 2011-06-12, departing from Pointe A Pitre, Guadeloupe and returning to St. George's, Bermuda

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  16. Multibeam collection for TN236: Multibeam data collected aboard Thomas G. Thompson from 2009-06-12 to 2009-07-01, departing from Nuku'alofa, Tonga and returning to Apia, Western Samoa

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  17. Multibeam collection for TUIM07MV: Multibeam data collected aboard Melville from 2005-06-09 to 2005-06-29, departing from Suva, Fiji and returning to Suva, Fiji

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  18. Multibeam collection for HLY06TD: Multibeam data collected aboard Healy from 2006-04-30 to 2006-05-06, departing from Seattle, WA and returning to Dutch Harbor, AK

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  19. Multibeam collection for HLY11TD: Multibeam data collected aboard Healy from 2011-08-05 to 2011-08-15, departing from Seward, AK and returning to Barrow, AK

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  20. Multibeam collection for HLY03TD: Multibeam data collected aboard Healy from 2003-08-19 to 2003-08-29, departing from Thule, Greenland and returning to Barrow, AK

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  1. Multibeam collection for HLY04TD: Multibeam data collected aboard Healy from 2004-08-26 to 2004-08-28, departing from Nome, AK and returning to Dutch Harbor, AK

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  2. Multibeam collection for HLY14TD: Multibeam data collected aboard Healy from 2014-07-31 to 2014-08-03, departing from Dutch Harbor, AK and returning to Seward, AK

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  3. Multibeam collection for HLY10TD: Multibeam data collected aboard Healy from 2010-07-28 to 2010-07-31, departing from Seward, AK and returning to Dutch Harbor, AK

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  4. Multibeam collection for HLY08TD: Multibeam data collected aboard Healy from 2008-05-07 to 2008-05-11, departing from Dutch Harbor, AK and returning to Juneau, AK

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  5. Multibeam collection for HLY13TD: Multibeam data collected aboard Healy from 2013-11-02 to 2013-11-08, departing from Dutch Harbor, AK and returning to Seattle, WA

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  6. Multibeam collection for HLY05TD: Multibeam data collected aboard Healy from 2005-07-27 to 2005-07-31, departing from Barrow, AK and returning to Dutch Harbor, AK

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  7. Multibeam collection for HLY07TD: Multibeam data collected aboard Healy from 2007-06-19 to 2007-06-25, departing from Dutch Harbor, AK and returning to Seattle, WA

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  8. Multibeam collection for KM0406: Multibeam data collected aboard Kilo Moana from 2004-03-05 to 2004-03-14, departing from Honolulu, HI and returning to Honolulu, HI

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  9. Multibeam collection for KNOX12RR: Multibeam data collected aboard Roger Revelle from 2007-11-28 to 2007-12-09, departing from Port Louis, Mauritius and returning to Durban, South Africa

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  10. Multibeam collection for NBP0306: Multibeam data collected aboard Nathaniel B. Palmer from 2004-01-04 to 2004-01-15, departing from McMurdo Station, Antarctica and returning to McMurdo Station, Antarctica

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  11. Multibeam collection for KM0513: Multibeam data collected aboard Kilo Moana from 2005-06-13 to 2005-06-17, departing from Honolulu, HI and returning to Honolulu, HI

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  12. Multibeam collection for M31L2: Multibeam data collected aboard Meteor from 1995-02-09 to 1995-02-27, departing from Port Said, Egypt and returning to Djibouti, Djibouti

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  13. Multibeam collection for EW0306: Multibeam data collected aboard Maurice Ewing from 2003-08-01 to 2003-08-19, departing from Balboa, Panama and returning to Bergen, Norway

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  14. Multibeam collection for HLY0102: Multibeam data collected aboard Healy from 2001-08-02 to 2001-09-29, departing from Tromso, Norway and returning to Tromso, Norway

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  15. Multibeam collection for KN177L02: Multibeam data collected aboard Knorr from 2004-05-08 to 2004-05-18, departing from Bergen, Norway and returning to Bergen, Norway

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  16. Multibeam collection for KN179L03: Multibeam data collected aboard Knorr from 2004-08-29 to 2004-09-11, departing from Bergen, Norway and returning to Reykjavik, Iceland

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  17. Multibeam collection for HLY0503: Multibeam data collected aboard Healy from 2005-08-04 to 2005-09-29, departing from Dutch Harbor, AK and returning to Tromso, Norway

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  18. Multibeam collection for HLY0103: Multibeam data collected aboard Healy from 2001-10-27 to 2001-11-28, departing from Tromso, Norway and returning to Tromso, Norway

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  19. Multibeam collection for EW0308: Multibeam data collected aboard Maurice Ewing from 2003-10-02 to 2003-10-18, departing from Bergen, Norway and returning to Bridgetown, Barbados

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  20. Multibeam collection for KN177L03: Multibeam data collected aboard Knorr from 2004-05-20 to 2004-06-04, departing from Bergen, Norway and returning to Woods Hole, MA

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  1. Multibeam collection for HLY05TE: Multibeam data collected aboard Healy from 2005-09-29 to 2005-11-03, departing from Tromso, Norway and returning to Dublin, Ireland

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  2. Multibeam collection for KN179L02: Multibeam data collected aboard Knorr from 2004-08-18 to 2004-08-26, departing from St. John's, Newfoundland and returning to Bergen, Norway

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  3. Multibeam collection for EW9008: Multibeam data collected aboard Maurice Ewing from 1990-09-29 to 1990-10-26, departing from Bergen, Norway and returning to Newark, NJ

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  4. Multibeam collection for KN216-03: Multibeam data collected aboard Knorr from 2014-03-13 to 2014-04-01, departing from Tromso, Norway and returning to Woods Hole, MA

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  5. Multibeam collection for EW0307: Multibeam data collected aboard Maurice Ewing from 2003-08-29 to 2003-09-25, departing from Bergen, Norway and returning to Bergen, Norway

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  6. Multibeam collection for RR1514: Multibeam data collected aboard Roger Revelle from 2015-09-22 to 2015-10-07, departing from Chennai, India and returning to Palau, Palau

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  7. Multibeam collection for KNOX09RR: Multibeam data collected aboard Roger Revelle from 2007-09-20 to 2007-10-18, departing from Mormugao, India and returning to Mormugao, India

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  8. Multibeam collection for RR1513: Multibeam data collected aboard Roger Revelle from 2015-08-23 to 2015-09-21, departing from Chennai, India and returning to Chennai, India

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  9. Multibeam collection for KNOX07RR: Multibeam data collected aboard Roger Revelle from 2007-08-14 to 2007-08-21, departing from Singapore and returning to Mormugao, India

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  10. Multibeam collection for M27-3: Multibeam data collected aboard Meteor from 1994-02-26 to 1994-03-18, departing from Unknown Port and returning to Unknown Port

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  11. Multibeam collection for M28-2: Multibeam data collected aboard Meteor from 1994-05-27 to 1994-06-05, departing from Unknown Port and returning to Unknown Port

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  12. Multibeam collection for M25-3: Multibeam data collected aboard Meteor from 1993-07-04 to 1993-07-11, departing from Unknown Port and returning to Unknown Port

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  13. Multibeam collection for M29-2: Multibeam data collected aboard Meteor from 1994-07-15 to 1994-08-07, departing from Unknown Port and returning to Unknown Port

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  14. Multibeam collection for M32L6: Multibeam data collected aboard Meteor from 1995-08-17 to 1995-09-18, departing from Muscat, Oman and returning to Muscat, Oman

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  15. Multibeam collection for M26-3: Multibeam data collected aboard Meteor from 1993-10-28 to 1993-11-20, departing from Unknown Port and returning to Unknown Port

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  16. Multibeam collection for KM0401: Multibeam data collected aboard Kilo Moana from 2004-01-07 to 2004-01-14, departing from Honolulu, HI and returning to Honolulu, HI

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  17. Multibeam collection for KM0414: Multibeam data collected aboard Kilo Moana from 2004-06-20 to 2004-07-10, departing from Honolulu, HI and returning to Honolulu, HI

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  18. Multibeam collection for ZHNG09RR: Multibeam data collected aboard Roger Revelle from 2005-07-21 to 2005-08-27, departing from Yokohama, Japan and returning to Honolulu, HI

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  19. Multibeam collection for TN240: Multibeam data collected aboard Thomas G. Thompson from 2009-09-28 to 2009-10-14, departing from Apia, Samoa and returning to Seattle, WA

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  20. Multibeam collection for KM0405: Multibeam data collected aboard Kilo Moana from 2004-02-24 to 2004-03-03, departing from Honolulu, HI and returning to Honolulu, HI

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  1. Multibeam collection for REM-01MV: Multibeam data collected aboard Melville from 1993-08-10 to 1993-09-07, departing from San Diego, CA and returning to Astoria, OR

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  2. Multibeam collection for EX1105: Multibeam data collected aboard Okeanos Explorer from 2011-08-22 to 2011-09-10, departing from Key West, FL and returning to Pascagoula, MS

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  3. Multibeam collection for EX1202Leg2: Multibeam data collected aboard Okeanos Explorer from 2012-03-19 to 2012-04-07, departing from Tampa, FL and returning to Pascagoula, MS

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  4. Multibeam collection for A131L11: Multibeam data collected aboard Atlantis II from 1994-03-10 to 1994-03-22, departing from Acapulco, Mexico and returning to Manzanillo, Mexico

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  5. Multibeam collection for EX1402L2: Multibeam data collected aboard Okeanos Explorer from 2014-03-19 to 2014-04-04, departing from Galveston, TX and returning to Pascagoula, MS

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  6. Multibeam collection for TN247: Multibeam data collected aboard Thomas G. Thompson from 2010-03-11 to 2010-04-17, departing from Punta Arenas, Chile and returning to Seattle, WA

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  7. Multibeam collection for NBP1305: Multibeam data collected aboard Nathaniel B. Palmer from 2013-06-24 to 2013-07-27, departing from Valparaiso, Chile and returning to Valparaiso, Chile

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  8. Multibeam collection for SU9201: Multibeam data collected aboard Surveyor from 1992-12-18 to 1992-12-19, departing from San Diego, CA and returning to Valparaiso, Chile

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  9. Multibeam collection for NBP0702: Multibeam data collected aboard Nathaniel B. Palmer from 2007-02-03 to 2007-03-23, departing from McMurdo Station, Antarctica and returning to Punta Arenas, Chile

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  10. Multibeam collection for NBP9904: Multibeam data collected aboard Nathaniel B. Palmer from 1999-04-15 to 1999-05-10, departing from Punta Arenas, Chile and returning to Punta Arenas, Chile

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  11. Multibeam collection for NBP0003: Multibeam data collected aboard Nathaniel B. Palmer from 2000-05-10 to 2000-06-01, departing from Punta Arenas, Chile and returning to Punta Arenas, Chile

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  12. Multibeam collection for NBP0502: Multibeam data collected aboard Nathaniel B. Palmer from 2005-03-31 to 2005-04-23, departing from Punta Arenas, Chile and returning to Punta Arenas, Chile

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  13. Multibeam collection for NBP0501B: Multibeam data collected aboard Nathaniel B. Palmer from 2005-03-03 to 2005-03-21, departing from Lyttelton, New Zealand and returning to Punta Arenas, Chile

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  14. Multibeam collection for MV1015: Multibeam data collected aboard Melville from 2010-11-18 to 2010-12-14, departing from Arica, Chile and returning to Isla De Pascua, Chile

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  15. Multibeam collection for NBP0103: Multibeam data collected aboard Nathaniel B. Palmer from 2001-04-24 to 2001-06-05, departing from Punta Arenas, Chile and returning to Punta Arenas, Chile

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  16. Multibeam collection for KN182L10: Multibeam data collected aboard Knorr from 2006-01-04 to 2006-01-25, departing from Manzanillo, Mexico and returning to Punta Arenas, Chile

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  17. Multibeam collection for NBP9704B: Multibeam data collected aboard Nathaniel B. Palmer from 1997-07-20 to 1997-07-25, departing from Talcahuano, Chile and returning to Punta Arenas, Chile

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  18. Multibeam collection for NBP1105: Multibeam data collected aboard Nathaniel B. Palmer from 2011-09-17 to 2011-11-04, departing from Punta Arenas, Chile and returning to Punta Arenas, Chile

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  19. Multibeam collection for AT2L5: Multibeam data collected aboard Atlantis from 1997-05-22 to 1997-05-24, departing from Norfolk, VA and returning to Woods Hole, MA

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  20. Multibeam collection for HLY0701: Multibeam data collected aboard Healy from 2007-04-10 to 2007-05-12, departing from Dutch Harbor, AK and returning to Dutch Harbor, AK

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...