The Experts below are selected from a list of 19281 Experts worldwide ranked by ideXlab platform
Zhou Hai-yin - One of the best experts on this subject based on the ideXlab platform.
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Application of Spline Model to LEO Precise Orbit Determination Simulation
Computer Simulation, 2006Co-Authors: Zhou Hai-yinAbstract:Considering the time pertinency of to-be-estimated parameters in LEO's precise Orbit Determination based on Bi-satellite Positioning System(BPS),this paper puts forward a new method of precise Orbit Determination with reduced parameter modeling which syncretizes the discrete state information and spline model.This paper establishes LEO Orbit parameters and system error parameters estimation models based on cube standard B-spline,and designs an improved fusion algorithm aiming at spline to-be-estimated coefficient based on traditional precise Orbit Determination numerical algorithm and carries out Orbit Determination simulation experiment by simulating range sum observation data.Theoretic analysis and simulation computation results show that this method can gain better LEO Orbit Determination precision by avoiding approximate linearity of design matrix,and has the characteristic of faster computation and higher stability.
Byron D Tapley - One of the best experts on this subject based on the ideXlab platform.
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statistical Orbit Determination
2004Co-Authors: Byron D Tapley, Bob E Schutz, George H. BornAbstract:1 Orbit Determination Concepts 2 The Orbit Problem 3 Observations 4 Fundamentals of Orbit Determination 5 Square-root Solution Methods 6 Consider Covariance Analysis A Probability and Statistics B Review of Matrix Concepts C Equations of Motion D Constants E Analytical Theory for Near-Circular Orbits F Example of State Noise and Dynamic Model Compensation G Solution of the Linearized Equations of Motion H ECI and ECF Transformation
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Orbit Determination Concepts
Statistical Orbit Determination, 2004Co-Authors: Byron D Tapley, Bob E Schutz, George H. BornAbstract:This chapter discusses Orbit Determination concepts. The treatment presented in the chapter covers the fundamentals of satellite Orbit Determination and its evolution over the past four decades. Satellite Orbit Determination means the process by which one obtains knowledge of a satellite's motion relative to the center of mass of the Earth in a specified coordinate system. Orbit Determination for celestial bodies has been a general concern of astronomers and mathematicians since the beginning of civilization and indeed has attracted some of the best analytical minds to develop the basis for much of the fundamental mathematics. Orbit Determination methodology can be separated into two general classes: classical (or deterministic) Orbit Determination and modern (or statistical based) Orbit Determination. In the classical approach, observational errors are not considered and the problem is reduced to making the necessary number of measurements to determine the Orbit. The modern Orbit Determination problem recognizes the influence of observation errors and, to minimize the effects of the observational error, more observations are used than the number of parameters to be estimated.
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Chapter 4 – Fundamentals of Orbit Determination
Statistical Orbit Determination, 2004Co-Authors: Byron D TapleyAbstract:Publisher Summary This chapter discusses the fundamentals of Orbit Determination. This improvement in Orbit Determination accuracy was motivated by the ever increasing demands of scientists in the oceanographic and geodetic communities. In particular, the need for centimeter-level accuracy in global ocean topography obtained from altimetric satellites spurred extensive and unprecedented model improvements during the past two decades. The chapter describes the role of the measurement model in introducing nonlinearity to the process. In the general Orbit Determination problem, both the dynamics and the measurements involve significant nonlinear relationships. It illustrates the role of the estimation process in improving the force and measurement models as an integral step in the process.
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chapter 4 fundamentals of Orbit Determination
Statistical Orbit Determination, 2004Co-Authors: Byron D TapleyAbstract:Publisher Summary This chapter discusses the fundamentals of Orbit Determination. This improvement in Orbit Determination accuracy was motivated by the ever increasing demands of scientists in the oceanographic and geodetic communities. In particular, the need for centimeter-level accuracy in global ocean topography obtained from altimetric satellites spurred extensive and unprecedented model improvements during the past two decades. The chapter describes the role of the measurement model in introducing nonlinearity to the process. In the general Orbit Determination problem, both the dynamics and the measurements involve significant nonlinear relationships. It illustrates the role of the estimation process in improving the force and measurement models as an integral step in the process.
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Precise Orbit Determination with GPS.
1996Co-Authors: H. Rim, G. E. Powell, Byron D TapleyAbstract:The Global Positioning System (GPS) is likely to become a powerful means in precise Orbit Determination (POD) of low-Orbiting earth satellites as long as it can fully cover the satellites. With its continuous tracking and coverage capabilities, this system can realize not only conventional dynamic precise Orbit Determination, but kinematic Orbit Determination as well. Technically, by smoothing the pseudo-range measurement values derived from at least 4 GPS satellites by using the carrier wave measurement values, the geocentric position at the phase center of the antenna and the clock correction values of the user satellites can be determined. This project focused on investigating Orbit Determination methods through a simulation and covariance analysis with several dynamic and measurement error models. The Orbital uncertainty generated by these models was found to be roughly equivalent to the sidereal error estimated in processing actual GPS data. In this case, the covariance analysis, when adjusted, was able to reflect these errors and to reveal the characteristics of various filtering techniques.
K. Sommar - One of the best experts on this subject based on the ideXlab platform.
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Statistical initial Orbit Determination
Journal of Spacecraft and Rockets, 1992Co-Authors: Laurence G. Taff, B. Belkin, G. A. Schweiter, K. SommarAbstract:For the ballistic missile initial Orbit Determination problem in particular, the concept of 'launch folders' is extended. This allows to decouple the observational data from the initial Orbit Determination problem per se. The observational data is only used to select among the possible Orbital element sets in the group of folders. Monte Carlo simulations using up to 7200 Orbital element sets are described. The results are compared to the true Orbital element set and the one a good radar would have been able to produce if collocated with the optical sensor. The simplest version of the new method routinely outperforms the radar initial Orbital element set by a factor of two in future miss distance. In addition, not only can a differentially corrected Orbital element set be produced via this approach - after only two measurements of direction - but also an updated, meaningful, six-dimensional covariance array for it can be calculated. This technique represents a significant advance in initial Orbit Determination for this problem, and the concept can easily be extended to minor planets and artificial satellites. 9 refs.
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Statistical Initial Orbit Determination
Signal and Data Processing of Small Targets 1991, 1991Co-Authors: Laurence G. Taff, B. Belkin, G. A. Schweiter, K. SommarAbstract:We abandon, as a futile endeavor, the computation of a meaningful initial Orbital element set based on anglesonly data. Rather, for the ballistic missile intitial Orbit Determination problem in particular, the concept of "launch folders" is extended. This allows one to decouple the observational data from the initial Orbit Determination problem per se. The observational data is only used to select among the possible Orbital element sets in the group of folders. Monte Carlo simulations using up to 7200 Orbital element sets are described herein. The results are compared to the true Orbital element set and the one a good radar would have been able to produce if co—located with the optical sensor. The simplest version of the new method routinely outperforms the radar initial Orbital element set by a factor of two in future miss distance. In addition, not only can one produce a differentially corrected Orbital element set via this approach—after only two measurements of direction—one can also calculate an updated, meaningful, six-dimensional covariance array for it. This technique represents a significant advance in initial Orbit Determination for this problem and the concept can easily be extended to minor planets and artificial satellites.
Wang Xin - One of the best experts on this subject based on the ideXlab platform.
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A Robust Method of Preliminary Orbit Determination
Chinese Astronomy and Astrophysics, 2013Co-Authors: Wang XinAbstract:Abstract The preliminary Orbit Determination with optical angular measure- ments plays an important role in the survey of space objects. The classical method of Orbit computation based on the least square error estimation is not robust while outliers occur in the observation. A robust method is proposed by employing the least absolute deviation estimation. The method reduces the problem of Orbit Determination to a linear programming problem, and gives the variance of the estimation with the bootstrap method. Numerical check shows that the method is effective and robust, and has a high breakdown point.
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The Bootstrap Estimation of the Accuracy of Preliminary Orbit Determination
Chinese Astronomy and Astrophysics, 2013Co-Authors: Wang XinAbstract:Abstract From the point of view of the non-parametric statistics, a general estimation method of the accuracy and confidence interval of preliminary Orbit Determination is proposed for the occasion without any other information but observational data. Based on the bootstrap method, the estimation relies only on the observational data and does not require the precise Orbit Determination as a reference, or the assumption of normal distribution of observational errors. Numerical experiments show that this method is very simple in implementa- tion, and may serve as an easy accuracy evaluation for the preliminary Orbit Determination and for the follow-up employments.
George H. Born - One of the best experts on this subject based on the ideXlab platform.
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statistical Orbit Determination
2004Co-Authors: Byron D Tapley, Bob E Schutz, George H. BornAbstract:1 Orbit Determination Concepts 2 The Orbit Problem 3 Observations 4 Fundamentals of Orbit Determination 5 Square-root Solution Methods 6 Consider Covariance Analysis A Probability and Statistics B Review of Matrix Concepts C Equations of Motion D Constants E Analytical Theory for Near-Circular Orbits F Example of State Noise and Dynamic Model Compensation G Solution of the Linearized Equations of Motion H ECI and ECF Transformation
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Orbit Determination Concepts
Statistical Orbit Determination, 2004Co-Authors: Byron D Tapley, Bob E Schutz, George H. BornAbstract:This chapter discusses Orbit Determination concepts. The treatment presented in the chapter covers the fundamentals of satellite Orbit Determination and its evolution over the past four decades. Satellite Orbit Determination means the process by which one obtains knowledge of a satellite's motion relative to the center of mass of the Earth in a specified coordinate system. Orbit Determination for celestial bodies has been a general concern of astronomers and mathematicians since the beginning of civilization and indeed has attracted some of the best analytical minds to develop the basis for much of the fundamental mathematics. Orbit Determination methodology can be separated into two general classes: classical (or deterministic) Orbit Determination and modern (or statistical based) Orbit Determination. In the classical approach, observational errors are not considered and the problem is reduced to making the necessary number of measurements to determine the Orbit. The modern Orbit Determination problem recognizes the influence of observation errors and, to minimize the effects of the observational error, more observations are used than the number of parameters to be estimated.
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Orbit Determination for the QuikSCAT Spacecraft
Journal of Spacecraft and Rockets, 2002Co-Authors: Blair F. Thompson, George H. Born, M. C. Meek, Kenn Gold, Penina Axelrad, Daniel G. KubitschekAbstract:An operational Orbit Determination system for QuikSCAT has been developed to meet the requirement for 100-m(3ae) positioning knowledge. This is nominally accomplished by processing global positioning system (GPS) position solutions in a dynamic e lter. The operational Orbit Determination system produced 24-h overlapping arc position errors between 15 and 25 m (root-sum-square )and 3-h arc overlaps between 5 and 6 m (root-sum-square ) for seven-day and one-day arcs, respectively. We also investigated the use of short segments of GPS pseudorange and carrier phase data and obtained results that differ by less than 10 m from the nominal Orbit solutions. A third investigation considered the feasibility of a backup Orbit Determination system using antenna azimuth and elevation angles from three ground tracking stations. The methods and results of processing these three data types are presented.
