The Experts below are selected from a list of 315 Experts worldwide ranked by ideXlab platform
R. Sridharan - One of the best experts on this subject based on the ideXlab platform.
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U.S. Space Surveillance Network capabilities
Image Intensifiers and Applications; and Characteristics and Consequences of Space Debris and Near-Earth Objects, 1998Co-Authors: R. Sridharan, Antonio F. PensaAbstract:The U.S. Space Command maintains a positional catalog of over 8000 man-made Space objects. The basis of this catalog is the observational data collected by a worldwide network of radars and optical sites known collectively as the U.S. Space Surveillance Network which is operated by the U.S. Air Force, Army and Navy. This network was developed following the launch of the first SPUTNIK in 1957 at which time the Air Force was given the task by the U.S. Congress of maintaining a catalog of all the detectable objects in Space-active and inactive satellites, spent boosters and other miscellaneous jetsam that constitute the dangerous portion of the Space debris population. The fundamental mission of the Space Surveillance network is to keep reliable, up-to-date information on all detectable resident Space objects (RSOs) in Space. The sensors in the network are primarily ground-based except for a recent sensor that was deployed in Space. The capabilities of the network are described in this paper. Specific examples will be used to demonstrate that the Space Surveillance network constitutes a capable and extensive remote sensing system for resident Space objects and debris.
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Monitoring Objects in Space with the U.S. Space Surveillance Network
Mission Design & Implementation of Satellite Constellations, 1998Co-Authors: Antonio F. Pensa, R. SridharanAbstract:At present the U.S. Space Command maintains a positional catalog of more than 8000 man-made Space objects. The basis of this catalog is the observational data collected by a worldwide network of radars and optical sites known collectively as the U.S. Space Surveillance Network. This paper describes the network including its capability to support large constellations of satellites. The evolution of the network from its beginnings following the launch of SPUTNIK is described. The various network componets as well as their unique contributions are viewed.
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Proceedings of the Annual Space Surveillance Workshop (12th) Held in Lexington, Massachusetts on 5-7 April 1994. Volume 1
1994Co-Authors: K. P. Schwan, R. Sridharan, D. M. Rodvold, Michael J. Muolo, David Cappellucci, Stephen H. Knowels, J. M. Rumreigh, R.e. Firpo, R. John, P. D. TennysonAbstract:Abstract : The twelfth Annual Space Surveillance Workshop hosted by MIT Lincoln Laboratory was held 5-7 April 1994. The purpose of this series of workshops is to provide a forum for the presentation and discussion of Space Surveillance issues. This Proceedings documents most of the presentations from this workshop that did not appear in Vol. 1. The papers contained were reproduced directly from copies supplied by their authors (with minor mechanical changes where necessary). It is hoped that this publication will enhance the utility of the workshop.
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Proceedings of the Space Surveillance Workshop (11th) Held in Lexington, Massachusetts on 30 March-1 April 1993. Volume 1
1993Co-Authors: R W Miller, R. SridharanAbstract:Abstract : This report of Proceedings of the 1993 Space Surveillance Workshop include the following topics: The Maui Space Surveillance Site Infrared Calibration Sources; Infrared Detection of Geosynchronous Objects at AMOS; LWIR Observations of Geosynchronous Satellites; LAGEOS-2 Launch Support Navigation at JPL; Space Surveillance Network Sensor Contribution Analysis; NMD-GBR: New X- Band Sensors at Sites in CONUS and USAKA for Space Surveillance; Recent Improvements at ALTAIR; Enhancements to the ALCOR Imaging Radar; Fiber Optic Phase Control of the Like Kickapoo NAVSPASUR Transmitter; Coherent Data Recording and Signal Processing Capabilities at Ascension FPQ-15 Radar for Space Surveillance Applications; Forecasting Trans-Ionospheric Effects to Improve Space Surveillance
Aubrey B. Poore - One of the best experts on this subject based on the ideXlab platform.
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Short Arc Gating in Multiple Hypothesis Tracking for Space Surveillance
Proceedings of the Society of Photo-Optical Instrumentation Engineers, 2012Co-Authors: Sabino M. Gadaleta, Joshua T. Horwood, Aubrey B. PooreAbstract:Multiple hypothesis tracking methods are under development for Space Surveillance and one challenge is the accurate and timely orbit initiation from sets of uncorrelated optical observations. This paper develops gating methods for correlation of optical observations in Space Surveillance. A pair gate based on the concept of an admissible region is introduced. By implementing a hierarchy from fast, but coarse, to more expensive, but accurate gates, the number of hypotheses to be considered for initial orbit determination is reduced considerably. Simulation results demonstrate the e ectiveness of the gating procedure, address gate parameter determination, and study the accuracy of initial orbits.
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A Gaussian sum filter framework for Space Surveillance
Signal and Data Processing of Small Targets 2011, 2011Co-Authors: Joshua T. Horwood, Nathan D. Aragon, Aubrey B. PooreAbstract:While standard Kalman-based filters, Gaussian assumptions, and covariance-weighted metrics work remarkably well in data-rich tracking environments such as air and ground, their use in the data-sparse environment of Space Surveillance is more limited. In order to properly characterize non-Gaussian density functions arising in the problem of long term propagation of state uncertainties in the two-body problem, a framework for a Gaussian sum filter is described which achieves uncertainty (covariance) consistency and an accurate approximation to the Fokker-Planck equation up to a prescribed accuracy. The filter is made efficient and practical by (i) using coordinate systems adapted to the physics (i.e., orbital elements), (ii) only requiring a Gaussian sum to be defined along one of the six state Space dimensions, and (iii) the ability to initially select the component means, covariances, and weights by way of a lookup table generated by solving an offline nonlinear optimization problem. The efficacy of the Gaussian sum filter and the improvements over the traditional unscented Kalman filter are demonstrated within the problems of data association and maneuver detection.
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Adaptive Gaussian Sum Filters for Space Surveillance
IEEE Transactions on Automatic Control, 2011Co-Authors: Joshua T. Horwood, Aubrey B. PooreAbstract:The representation of the uncertainty of a stochastic state by a Gaussian mixture is well-suited for nonlinear tracking problems in high dimensional data-starved environments such as Space Surveillance. In this paper, the framework for a Gaussian sum filter is developed emphasizing how the uncertainty can be propagated accurately over extended time periods in the absence of measurement updates. To achieve this objective, a series of metrics constructed from tensors of higher-order cumulants are proposed which assess the consistency of the uncertainty and provide a tool for implementing an adaptive Gaussian sum filter. Emphasis is also placed on the algorithm's potential for parallelization which is complemented by the use of higher-order unscented filters based on efficient multidimensional Gauss-Hermite quadrature schemes. The effectiveness of the proposed Gaussian sum filter is illustrated in a case study in Space Surveillance involving the tracking of an object in a six-dimensional state Space.
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Gaussian Sum Filters for Space Surveillance: Theory and Simulations
Journal of Guidance Control and Dynamics, 2011Co-Authors: Joshua T. Horwood, Nathan D. Aragon, Aubrey B. PooreAbstract:While standard Kalman-based filters, Gaussian assumptions, and covariance-weighted metrics are very effective in data-rich tracking environments, their use in the data-sparse environment of Space Surveillance ismore limited. To properly characterize non-Gaussian density functions arising in the problem of long-term propagation of state uncertainties, a Gaussian sum filter adapted to the two-body problem in Space Surveillance is proposed and demonstrated to achieve uncertainty consistency. The proposed filter is made efficient by using only a onedimensional Gaussian sum in equinoctial orbital elements, thereby avoiding the expensive representation of a full six-dimensional mixture and hence the “curse of dimensionality.” Additionally, an alternate set of equinoctial elements is proposed and is shown to provide enhanced uncertainty consistently over the traditional element set. Simulation studies illustrate the improvements in theGaussian sumapproach over the traditional unscentedKalman filter and the impact of correct uncertainty representation in the problems of data association (correlation) and anomaly (maneuver) detection.
Saso Blazic - One of the best experts on this subject based on the ideXlab platform.
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ROBIO - Image based control of a Space Surveillance robot
2011 IEEE International Conference on Robotics and Biomimetics, 2011Co-Authors: Drago Matko, Tomaz Rodic, Gregor Klančar, Gašper Mušič, Saso BlazicAbstract:The paper deals with the image-based control of a Space Surveillance robot. The position of the robot is obtained by the Simplified General Perturbations model and its orientation by simulating its dynamic and kinematic models. For known position and orientation of the robot the images are obtained using Google Earth. The orientation of the robot is governed by reaction wheels which produce the required moments to the robot. The image based control law using image extraction features is applied to achieve automatic reference point observation on the Earth surface. Simulated experimental results with realistic assumptions are provided to demonstrate the operation of the proposed approach.
Tim Flohrer - One of the best experts on this subject based on the ideXlab platform.
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SBSS Demonstrator: A Design for Efficient Demonstration of Space-Based Space Surveillance End-To-End Capabilities
Space Safety is No Accident, 2015Co-Authors: Jens Utzmann, Thomas Schildknecht, A. Wagner, Jiri Silha, P. Willemsen, F. Teston, Tim FlohrerAbstract:This paper presents the capabilities of a Space-Based Space Surveillance (SBSS) demonstration mission for Space Surveillance and Tracking (SST) based on a micro-satellite platform. The results have been produced in the frame of ESA’s "Assessment Study for Space Based Space Surveillance Demonstration Mission" performed by the Airbus Defence and Space consortium.
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A system design for Space-based Space Surveillance
2014Co-Authors: Jens Utzmann, Thomas Schildknecht, A. Wagner, Jiri Silha, P. Willemsen, F. Teston, Tim FlohrerAbstract:This paper presents the capabilities of a Space-Based Space Surveillance (SBSS) demonstration mission for Space Surveillance and Tracking (SST) based on a micro- satellite platform. The results have been produced in the frame of ESA’s "As sessment Study for Space Based Space Surveillance Demonstration Mission (Phase A) " performed by the Airbus DS consortium. Space Surveillance and Tracking is part of Space Situational Awareness (SSA) and covers the detection, tracking and cataloguing of spa ce debris and satellites. Derived SST services comprise a catalogue of these man-made objects, collision warning, detection and characterisation of in-orbit fragmentations, sub-catalogue debris characterisation, etc. The assessment of SBSS in an SST system architecture has shown that both an operational SBSS and also already a well - designed Space-based demonstrator can provide substantial performance in terms of Surveillance and tracking of beyond - LEO objects. Especially the early deployment of a demonstrator, possible by using standard equipment, could boost initial operating capability and create a self-maintained object catalogue. Unlike classical technology demonstration missions, the primary goal is the demonstration and optimisation of the functional elements in a complex end-to-end chain (mission planning, observation strategies, data acquisition, processing and fusion, etc.) until the final products can be offered to the users. The presented SBSS system concept takes the ESA SST System Requirements (derived within the ESA SSA Preparatory Program) into account and aims at fulfilling some of the SST core requirements in a stand-alone manner. The evaluation of the concept has shown that an according solution can be implemented with low technological effort and risk. The paper presents details of the system concept, candidate micro - satellite platforms, the observation strategy and the results of performance simulations for GEO coverage and cataloguing accuracy
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Space-based Space Surveillance and tracking demonstrator: mission and system design
2014Co-Authors: Jens Utzmann, Thomas Schildknecht, A. Wagner, Jiri Silha, P. Willemsen, F. Teston, Tim FlohrerAbstract:This paper presents the capabilities of a Space-Based Space Surveillance (SBSS) demonstration mission for Space Surveillance and Tracking (SST) based on a micro-satellite platform. The results have been produced in the frame of ESA’s "Assessment Study for Space Based Space Surveillance Demonstration Mission" performed by the Airbus Defence and Space consortium. The assessment of SBSS in an SST system architecture has shown that both an operational SBSS and also already a well- designed Space-based demonstrator can provide substantial performance in terms of Surveillance and tracking of beyond-LEO objects. Especially the early deployment of a demonstrator, possible by using standard equipment, could boost initial operating capability and create a self-maintained object catalogue. Furthermore, unique statistical information about small-size LEO debris (mm size) can be collected in-situ. Unlike classical technology demonstration missions, the primary goal is the demonstration and optimisation of the functional elements in a complex end-to-end chain (mission planning, observation strategies, data acquisition, processing, etc.) until the final products can be offered to the users and with low technological effort and risk. The SBSS system concept takes the ESA SST System Requirements into account and aims at fulfilling SST core requirements in a stand-alone manner. Additionally, requirements for detection and characterisation of small-sizedLEO debris are considered. The paper presents details of the system concept, candidate micro-satellite platforms, the instrument design and the operational modes. Note that the detailed results of performance simulations for Space debris coverage and cataloguing accuracy are presented in a separate paper “Capability of a Space-based Space Surveillance System to Detect and Track Objects in GEO, MEO and LEO Orbits” by J. Silha (AIUB) et al., IAC-14, A6, 1.1x25640.
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Conceptual Design of a European Space Surveillance System
2008Co-Authors: T. Donath, T. Michal, X Vanwijck, B Dugrosprez, Tim Flohrer, Thomas SchildknechtAbstract:Space Surveillance denotes the task of systematically surveying and tracking all objects above a certain size and maintaining a catalogue with updated orbital and physical characteristics for these objects. Space Surveillance is gaining increased importance as the operational safety of Spacecraft is depending on it. Presently, Europe has no operational capability for Space Surveillance, and is strongly dependant on external information from the USA and Russia.
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Proposed strategies for optical observations in a future European Space Surveillance network
Advances in Space Research, 2008Co-Authors: Tim Flohrer, Thomas Schildknecht, Reto MusciAbstract:Abstract Two ESA-funded feasibility studies that aimed to develop observation strategies, to propose suitable sensor architectures, and to assess the expected performance of an independent European Space Surveillance System were carried out during the last years. The French company ONERA led two study teams comprising a number of European companies. The proposed Space Surveillance system consists of two subsystems, a phased-array radar system that shall be located in the South of Spain, and a network of ground-based electro-optical telescopes at four low latitude sites. This system allows to build-up and to maintain a catalogue of orbital elements of objects in Space. It provides means to perform additional Space Surveillance tasks such as independent detection of fragmentation events, launches or manoeuvres, and allows to acquire the necessary measurements to assess the collision risk between catalogued objects. As a member of both study teams, the Astronomical Institute of the University of Bern (AIUB), Switzerland, contributed to the observation strategy definition, the system design, and the performance estimation of the optical observation part of the Space Surveillance system. This part of the system is intended to cover the Geostationary Orbit (GEO) and the Medium Earth Orbit (MEO) regions. This paper focuses on the development and evaluation of observation strategies for GEO and MEO within a Space Surveillance network. Observation requirements, possible strategies fulfilling the requirements, and the expected performance of selected strategies in terms of the coverage of a reference population are addressed. We conclude that GEO and MEO shall be covered by “stripe-scanning” approaches carried out by a network of telescopes. The simulations of the approaches using a reference population reveal that for both regions a nearly complete coverage can be guaranteed within a short time.
Thomas Schildknecht - One of the best experts on this subject based on the ideXlab platform.
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Scoring sensor observations to facilitate the exchange of Space Surveillance data
Advances in Space Research, 2017Co-Authors: Martin Weigel, Hauke Fiedler, Thomas SchildknechtAbstract:In this paper, a scoring metric for Space Surveillance sensor observations is introduced. A scoring metric allows for direct comparison of data quantity and data quality, and makes transparent the effort made by different sensor operators. The concept might be applied to various sensor types like tracking and Surveillance radar, active optical laser tracking, or passive optical telescopes as well as combinations of different measurement types. For each measurement type, a polynomial least squares fit is performed on the measurement values contained in the track. The track score is the average sum over the polynomial coefficients uncertainties and scaled by reference measurement accuracy. Based on the newly developed scoring metric, an accounting model and a rating model are introduced. Both models facilitate the exchange of observation data within a network of Space Surveillance sensors operators. In this paper, optical observations are taken as an example for analysis purposes, but both models can also be utilized for any other type of observations. The rating model has the capability to distinguish between network participants with major and minor data contribution to the network. The level of sanction on data reception is defined by the participants themselves enabling a high flexibility. The more elaborated accounting model translates the track score to credit points earned for data provision and spend for data reception. In this model, data reception is automatically limited for participants with low contribution to the network. The introduced method for observation scoring is first applied for transparent data exchange within the Small Aperture Robotic Telescope Network (SMARTnet). Therefore a detailed mathematical description is presented for line of sight measurements from optical telescopes, as well as numerical simulations for different network setups.
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SBSS Demonstrator: A Design for Efficient Demonstration of Space-Based Space Surveillance End-To-End Capabilities
Space Safety is No Accident, 2015Co-Authors: Jens Utzmann, Thomas Schildknecht, A. Wagner, Jiri Silha, P. Willemsen, F. Teston, Tim FlohrerAbstract:This paper presents the capabilities of a Space-Based Space Surveillance (SBSS) demonstration mission for Space Surveillance and Tracking (SST) based on a micro-satellite platform. The results have been produced in the frame of ESA’s "Assessment Study for Space Based Space Surveillance Demonstration Mission" performed by the Airbus Defence and Space consortium.
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A system design for Space-based Space Surveillance
2014Co-Authors: Jens Utzmann, Thomas Schildknecht, A. Wagner, Jiri Silha, P. Willemsen, F. Teston, Tim FlohrerAbstract:This paper presents the capabilities of a Space-Based Space Surveillance (SBSS) demonstration mission for Space Surveillance and Tracking (SST) based on a micro- satellite platform. The results have been produced in the frame of ESA’s "As sessment Study for Space Based Space Surveillance Demonstration Mission (Phase A) " performed by the Airbus DS consortium. Space Surveillance and Tracking is part of Space Situational Awareness (SSA) and covers the detection, tracking and cataloguing of spa ce debris and satellites. Derived SST services comprise a catalogue of these man-made objects, collision warning, detection and characterisation of in-orbit fragmentations, sub-catalogue debris characterisation, etc. The assessment of SBSS in an SST system architecture has shown that both an operational SBSS and also already a well - designed Space-based demonstrator can provide substantial performance in terms of Surveillance and tracking of beyond - LEO objects. Especially the early deployment of a demonstrator, possible by using standard equipment, could boost initial operating capability and create a self-maintained object catalogue. Unlike classical technology demonstration missions, the primary goal is the demonstration and optimisation of the functional elements in a complex end-to-end chain (mission planning, observation strategies, data acquisition, processing and fusion, etc.) until the final products can be offered to the users. The presented SBSS system concept takes the ESA SST System Requirements (derived within the ESA SSA Preparatory Program) into account and aims at fulfilling some of the SST core requirements in a stand-alone manner. The evaluation of the concept has shown that an according solution can be implemented with low technological effort and risk. The paper presents details of the system concept, candidate micro - satellite platforms, the observation strategy and the results of performance simulations for GEO coverage and cataloguing accuracy
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Space-based Space Surveillance and tracking demonstrator: mission and system design
2014Co-Authors: Jens Utzmann, Thomas Schildknecht, A. Wagner, Jiri Silha, P. Willemsen, F. Teston, Tim FlohrerAbstract:This paper presents the capabilities of a Space-Based Space Surveillance (SBSS) demonstration mission for Space Surveillance and Tracking (SST) based on a micro-satellite platform. The results have been produced in the frame of ESA’s "Assessment Study for Space Based Space Surveillance Demonstration Mission" performed by the Airbus Defence and Space consortium. The assessment of SBSS in an SST system architecture has shown that both an operational SBSS and also already a well- designed Space-based demonstrator can provide substantial performance in terms of Surveillance and tracking of beyond-LEO objects. Especially the early deployment of a demonstrator, possible by using standard equipment, could boost initial operating capability and create a self-maintained object catalogue. Furthermore, unique statistical information about small-size LEO debris (mm size) can be collected in-situ. Unlike classical technology demonstration missions, the primary goal is the demonstration and optimisation of the functional elements in a complex end-to-end chain (mission planning, observation strategies, data acquisition, processing, etc.) until the final products can be offered to the users and with low technological effort and risk. The SBSS system concept takes the ESA SST System Requirements into account and aims at fulfilling SST core requirements in a stand-alone manner. Additionally, requirements for detection and characterisation of small-sizedLEO debris are considered. The paper presents details of the system concept, candidate micro-satellite platforms, the instrument design and the operational modes. Note that the detailed results of performance simulations for Space debris coverage and cataloguing accuracy are presented in a separate paper “Capability of a Space-based Space Surveillance System to Detect and Track Objects in GEO, MEO and LEO Orbits” by J. Silha (AIUB) et al., IAC-14, A6, 1.1x25640.
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Conceptual Design of a European Space Surveillance System
2008Co-Authors: T. Donath, T. Michal, X Vanwijck, B Dugrosprez, Tim Flohrer, Thomas SchildknechtAbstract:Space Surveillance denotes the task of systematically surveying and tracking all objects above a certain size and maintaining a catalogue with updated orbital and physical characteristics for these objects. Space Surveillance is gaining increased importance as the operational safety of Spacecraft is depending on it. Presently, Europe has no operational capability for Space Surveillance, and is strongly dependant on external information from the USA and Russia.