Download or read book Orbit Determination in the Presence of Gravity Model Errors written by B. E. Schutz and published by . This book was released on 1972 with total page 41 pages. Available in PDF, EPUB and Kindle. Book excerpt: The precise determination of a satellite's position is of prime importance in satellite geodesy and in the use of satellites in studying geodynamics. It is not possible, however, to obtain a precise estimate of the satellite's position if sufficiently large errors exist in the gravity model. In this investigation, the application of a dynamic model compensation method to the problem of estimating the motion of a near-earth satellite in the presence of gravity model errors is described. Based on numerical results obtained in a computer simulation, it is concluded that the algorithm will yield an accurate estimate of the state in the presence of gravity model errors. The effects of the observation type and accuracy, station location and observation batch size on the accuracy of the orbit determination procedure are considered. Finally, it is shown that in addition to an accurate estimate of the position and velocity, the method can be used to obtain an accurate estimate of the unmodeled acceleration components. (Author).
Download or read book Analytical Approach to Orbit Determination in the Presence of Model Errors written by B. E. Schutz and published by . This book was released on 1973 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: The results of a study are presented in which a spacecraft's acceleration is separated into two components so that one component is tractable to analytical solution and the remaining component is treated as an unmodeled acceleration. By this procedure, an analytical solution to the dynamical equations used in the extended Kalman filter can be obtained. Two cases are considered: the modeled portion is taken to be the problem of two bodies with the perturbations treated as a model error, and the modeled portion is taken to be a straight line with all accelerations treated as a model error. The model error is approximated by a first-order Gauss-Markov process. The approach is evaluated using computer simulations of a lunar orbiter. (Author).
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 702 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Statistical Orbit Determination written by Bob Schutz and published by Elsevier. This book was released on 2004-06-26 with total page 563 pages. Available in PDF, EPUB and Kindle. Book excerpt: Statistical Orbit Determination presents fundmentals of orbit determination--from weighted least squares approaches (Gauss) to today's high-speed computer algorithms that provide accuracy within a few centimeters. Numerous examples and problems are provided to enhance readers' understanding of the material. Covers such topics as coordinate and time systems, square root filters, process noise techniques, and the use of fictitious parameters for absorbing un-modeled and incorrectly modeled forces acting on a satellite. Examples and exercises serve to illustrate the principles throughout each chapter.
Download or read book Satellite Dynamics written by G.E.O. Giacaglia and published by Springer Science & Business Media. This book was released on 2013-03-08 with total page 385 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume includes original papers presented at the 4th Symposium on Satellite Dynamics held at the XII Annual Plenary Meeting of COSPAR. At a time where it might be thought that very few problems were left un solved in celestial mechanics, we discover that new and more challenging questions must be answered. The pre cision of observations reaches the centimeter level and physical phenomena which had been disregarded come into play. We need a better treatment of atmospheric drag, radiation forces, and a better knowledge of the earth's gravitational field. Time has to be precisely defined as well as reference systems, including improved values for precision and nutation. The question of resonances introduced by nonzonal harmonics was to be carefully in vestigated. Numerical integration techniques must be optimized and means of controlling their errors improved. Analytical techniques must be made appropriate for com puter processing. Presently existing methods of solu tions of differential equations of interest to celestial mechanics are getting cumbersome as all these new facts come to light. It is clear that entirely new and more effective methods are necessary. These methods must, among other requirements, take into account the essential nonlinear character of the equations. Finally, the mo tion about the center of mass of a satellite is becoming an essential need for the thorough understanding and de scription of the orbital motion.
Download or read book Nonconservative Force Model Parameter Estimation Strategy for Topex Poseidon Precision Orbit Determination written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-09 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt: The TOPEX/Poseidon spacecraft was launched on August 10, 1992 to study the Earth's oceans. To achieve maximum benefit from the altimetric data it is to collect, mission requirements dictate that TOPEX/Poseidon's orbit must be computed at an unprecedented level of accuracy. To reach our pre-launch radial orbit accuracy goals, the mismodeling of the radiative nonconservative forces of solar radiation, Earth albedo an infrared re-radiation, and spacecraft thermal imbalances cannot produce in combination more than a 6 cm rms error over a 10 day period. Similarly, the 10-day drag modeling error cannot exceed 3 cm rms. In order to satisfy these requirements, a 'box-wing' representation of the satellite has been developed in which, the satellite is modelled as the combination of flat plates arranged in the shape of a box and a connected solar array. The radiative/thermal nonconservative forces acting on each of the eight surfaces are computed independently, yielding vector accelerations which are summed to compute the total aggregate effect on the satellite center-of-mass. Select parameters associated with the flat plates are adjusted to obtain a better representation of the satellite acceleration history. This study analyzes the estimation of these parameters from simulated TOPEX/Poseidon laser data in the presence of both nonconservative and gravity model errors. A 'best choice' of estimated parameters is derived and the ability to meet mission requirements with the 'box-wing' model evaluated. Luthcke, S. B. and Marshall, J. A. Goddard Space Flight Center ...
Download or read book Satellite Dynamics written by Giorgio E. O. Giacaglia and published by . This book was released on 1975 with total page 392 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Theory of Orbit Determination written by Andrea Milani and published by Cambridge University Press. This book was released on 2010 with total page 393 pages. Available in PDF, EPUB and Kindle. Book excerpt: Presents new algorithms for determining orbits; ideal for graduate students and researchers in applied mathematics, physics, astronomy and aerospace engineering.
Download or read book Effect of Gravity Model Error on Position Determination for Whitecloud Satellites written by E. Joyce Greeley and published by . This book was released on 1974 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Proceedings written by and published by . This book was released on 1973 with total page 402 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effect of Gravitational model Selection on Accuracy of Lunar Orbit Determination from Short Data Arcs written by Harold A. Hamer and published by . This book was released on 1969 with total page 50 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Treatise on Geophysics written by and published by Elsevier. This book was released on 2015-04-17 with total page 5604 pages. Available in PDF, EPUB and Kindle. Book excerpt: Treatise on Geophysics, Second Edition, is a comprehensive and in-depth study of the physics of the Earth beyond what any geophysics text has provided previously. Thoroughly revised and updated, it provides fundamental and state-of-the-art discussion of all aspects of geophysics. A highlight of the second edition is a new volume on Near Surface Geophysics that discusses the role of geophysics in the exploitation and conservation of natural resources and the assessment of degradation of natural systems by pollution. Additional features include new material in the Planets and Moon, Mantle Dynamics, Core Dynamics, Crustal and Lithosphere Dynamics, Evolution of the Earth, and Geodesy volumes. New material is also presented on the uses of Earth gravity measurements. This title is essential for professionals, researchers, professors, and advanced undergraduate and graduate students in the fields of Geophysics and Earth system science. Comprehensive and detailed coverage of all aspects of geophysics Fundamental and state-of-the-art discussions of all research topics Integration of topics into a coherent whole
Download or read book Geodesy and Physics of the Earth written by Horst Montag and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 482 pages. Available in PDF, EPUB and Kindle. Book excerpt: The investigation of the kinematics and dynamics of the Earth has achieved remarkable progresses in the last decades in understanding and explaining a large variety of geo- dynamical, geophysical and geological phenomena. The impact of increasingly precise geodetic space-time measurements and analyses have much contributed to these results. Papers presented atthe 7th International Symposium on Geodesy and Physics of the Earth focus onfour topics: - Present Day Tectonic Motions - Gravity Field and its Variation - Earth Rotation Characteristics - International Programs for Geodesy and Geodynamics Researchers and advanced students may use this volume as a comprehensive reference of concepts, techniques and results.
Download or read book On the Accuracy of an Elliptical Orbit Determination written by Robert F. Weirauch and published by . This book was released on 1961 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Satellite Gravity and the Geosphere written by National Research Council and published by National Academies Press. This book was released on 1997-09-02 with total page 126 pages. Available in PDF, EPUB and Kindle. Book excerpt: For the past three decades, it has been possible to measure the earth's static gravity from satellites. Such measurements have been used to address many important scientific problems, including the earth's internal structure, and geologically slow processes like mantle convection. In principle, it is possible to resolve the time-varying component of the gravity field by improving the accuracy of satellite gravity measurements. These temporal variations are caused by dynamic processes that change the mass distribution in the earth, oceans, and atmosphere. Acquisition of improved time-varying gravity data would open a new class of important scientific problems to analysis, including crustal motions associated with earthquakes and changes in groundwater levels, ice dynamics, sea-level changes, and atmospheric and oceanic circulation patterns. This book evaluates the potential for using satellite technologies to measure the time-varying component of the gravity field and assess the utility of these data for addressing problems of interest to the earth sciences, natural hazards, and resource communities.
Download or read book Petroleum Abstracts written by and published by . This book was released on 1972-10 with total page 786 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Continuing Kepler s Quest written by National Research Council and published by National Academies Press. This book was released on 2012-09-06 with total page 82 pages. Available in PDF, EPUB and Kindle. Book excerpt: In February 2009, the commercial communications satellite Iridium 33 collided with the Russian military communications satellite Cosmos 2251. The collision, which was not the first recorded between two satellites in orbit-but the most recent and alarming-produced thousands of pieces of debris, only a small percentage of which could be tracked by sensors located around the world. In early 2007, China tested a kinetic anti-satellite weapon against one of its own satellites, which also generated substantial amounts of space debris. These collisions highlighted the importance of maintaining accurate knowledge, and the associated uncertainty, of the orbit of each object in space. These data are needed to predict close approaches of space objects and to compute the probability of collision so that owners/operators can decide whether or not to make a collision avoidance maneuver by a spacecraft with such capability. The space object catalog currently contains more than 20,000 objects, and when the planned space fence radar becomes operational this number is expected to exceed 100,000. A key task is to determine if objects might come closer to each other, an event known as "conjunction," and the probability that they might collide. The U.S. Air Force is the primary U.S. government organization tasked with maintaining the space object catalog and data on all space objects. This is a complicated task, involving collecting data from a multitude of different sensors-many of which were not specifically designed to track orbiting objects-and fusing the tracking data along with other data, such as data from atmospheric models, to provide predictions of where objects will be in the future. The Committee for the Assessment of the U.S. Air Force's Astrodynamic Standards collected data and heard from numerous people involved in developing and maintaining the current astrodynamics standards for the Air Force Space Command (AFSPC), as well as representatives of the user community, such as NASA and commercial satellite owners and operators. Preventing collisions of space objects, regardless of their ownership, is in the national security interested of the United States. Continuing Kepler's Quest makes recommendations to the AFSPC in order for it to create and expand research programs, design and develop hardware and software, as well as determine which organizations to work with to achieve its goals.
