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NEW METHOD FOR ESTIMATING LOW-EARTH-ORBIT COLLISION PROBABILITIES

JOURNAL OF SPACECRAFT AND ROCKETS 1991年第2期28卷 210-215页

作者： VEDDER, JD TABOR, JL McDonnell Douglas Space Systems Co. Houston TX

An unconventional but general method is described for estimating the probability of collision between an Earth-orbiting spacecraft and orbital debris. This method uses a Monte Carlo simulation of the orbital motion of the target spacecraft and each discrete debris object to generate an empirical set of distances, each distance representing the separation between the spacecraft and the nearest debris object at random times. Using concepts from the asymptotic theory of extreme order statistics, an analytical density function is fitted to this set of minimum distances. From this function, it is possible to generate realistic collision estimates for the spacecraft.

关键词： Low Earth Orbit Monte Carlo Simulation probability density functions Orbital Debris Gamma Function Earth Target Spacecraft Space Stations Kepler's Equation Space Shuttle

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CRITICAL MODE INTERACTION IN THE PRESENCE OF EXTERNAL RANDOM-EXCITATION

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JOURNAL OF GUIDANCE CONTROL AND DYNAMICS 1991年第4期14卷 770-777页

作者： LENG, G NAMACHCHIVAYA, N University of Illinois Urbana Illinois 61820

The effects of random external excitation on nonlinear systems with marginally stable/unstable modes is studied within the context of stochastic bifurcation theory. Using the method of stochastic averaging, a Markov approximation is derived and a perturbation technique is developed to solve the resulting Fokker-Planck equation. It is found that, due to mode interaction through system nonlinearities, deterministic bifurcation characteristics are not preserved in the presence of external random excitation. In general, one critical mode can experience a stabilizing effect at the expense of the other. The theory is then applied to a flight dynamics problem at large angles of attack and sideslip.

关键词： Flow Conditions Lift Coefficient Airplane Dynamics Sideslip Angle Perturbation Method Flight Dynamics White Noise probability density functions Aerodynamic Coefficients Flight Testing

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Attitude-determination filtering via extended quaternion estimation

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JOURNAL OF GUIDANCE CONTROL AND DYNAMICS 2000年第2期23卷 206-214页

作者： Psiaki, ML Cornell Univ Ithaca NY 14853 USA

The quaternion estimation (QUEST) batch attitude-determination algorithm has been extended to work in a general Kalman-filter framework. This has been done to allow the inclusion of a complicated dynamics model and to allow the estimation of additional quantities beyond the attitude quaternion. The QUEST algorithm, which works with vector attitude observations, serves as a starting point because it is able to work with a poor (or no) first guess of the attitude. This paper's extended version of QUEST uses square-root information filtering techniques and linearization of the dynamics to propagate the state and its covariance. The measurement update problem is solved by a technique that is an extension of the original QUEST algorithm's eigenvalue/eigenvector solution. The paper demonstrates the new algorithm's performance on an attitude determination problem that uses star-tracker and rate-gyro measurements. The new algorithm is able to converge from initial attitude errors of 180 deg and initial rate-gyro bias errors as large as 2400 deg/h.

关键词： Quaternions Attitude Dynamics Algorithm Performance Attitude Determination Algorithms Quadratic Programming White Noise Numerical Integration Euler Equations probability density functions Spacecraft Missions

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Novel Laboratory Design of Passive Enhanced Surveillance System of Resident Space Objects

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JOURNAL OF SPACECRAFT AND ROCKETS 2018年第1期55卷 143-152页

作者： Cambria, Thomas Majeski, Joe Shrestha, Small Giakos, George C. Manhattan Coll Dept Elect & Comp Engn New York NY 10471 USA Image Sensors Grp ON Semicond San Jose CA 95136 USA

The objective of this study is to present a novel experimental laboratory design for polarimetric exploratory data analysis for the detection and discrimination of dimly lit resident space objects in the presence of starlight or cluttered luminous objects, or in the shadow of the Earth. The experimental results of this study indicate that fusion of polarimetric exploratory data analysis and Stokes parameters lead to reliable figures of merit that can be used as powerful tools for image analysis, detection, characterization, and discrimination of dim targets, under passive illumination. The outcome of this study allows for the design of planned future sensor systems through experimentation. modeling, and simulation, enabling the more accurate assessment of sensor requirements for space-to-space and Earth-to-space sensing of dimly lit resident space objects as well as anticipated sensor detection and discrimination potential.

关键词： Resident Space Object Sensor Systems Earth Data Analysis Image Analysis Optical Properties probability density functions Satellites Image Processing Space Situational Awareness

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Dispersion Analysis in Hypersonic Flight During Planetary Entry Using Stochastic Liouville Equation

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JOURNAL OF GUIDANCE CONTROL AND DYNAMICS 2011年第2期34卷 459-474页

作者： Halder, Abhishek Bhattacharya, Raktim Texas A&M Univ Dept Aerosp Engn College Stn TX 77843 USA

A framework is provided for the propagation of uncertainty in planetary entry, descent, and landing. The traditional Monte-Carlo based dispersion analysis is overly resource-expensive for such high-dimensional nonlinear systems and does not provide any methodical way to analyze the effect of uncertainty for mission design. It is shown that propagating the density function through Liouville equation is computationally attractive and suitable for further statistical analysis. Comparative simulation results are provided to bring forth the efficacies of the proposed method. Examples are given from the entry, descent, and landing domain to illustrate how one can retrieve statistical information of interest from an analyst's perspective.

关键词： Hypersonic Flight probability density functions Nonlinear Systems Flight Path Angle Mach Numbers Thermal Protection System Mars Science Laboratory Computing Jet Propulsion Laboratory Nonlinear Dynamics

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SHAPE DETERMINATION FOR LARGE FLEXIBLE SATELLITES VIA STEREO VISION

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JOURNAL OF SPACECRAFT AND ROCKETS 1992年第1期29卷 108-116页

作者： TSE, DNC HEPPLER, GR University of Waterloo Waterloo Ontario N2L 3G1 Canada

The use of stereo vision to determine the deformed shape of an elastic plate is investigated. The quantization error associated with using discrete charge coupled device camera images for this purpose is examined. An upper bound on the error is derived in terms of the stationary configuration parameters. An expression for the average (root mean square) error is also developed. The issue of interpolating the shape of the plate through erroneous data is addressed. The vibratory mode shapes are used as interpolation functions and two cases are considered: the case when the number of interpolation points (targets) is the same as the number of modes used in the interpolation, and the case when the number of targets exceeds the number of modes used. Error criteria are established for both cases and they provide a means of establishing the best fit to the measured data.

关键词： Satellites Charge Coupled Device Accelerometer probability density functions RADAR Flexible Structures Shape Control Elastic Structure Quadratic Programming Attitude Control

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Series for Collision probability in Short-Encounter Model

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JOURNAL OF GUIDANCE CONTROL AND DYNAMICS 2016年第8期39卷 1904-1912页

作者： Garcia-Pelayo, Ricardo Hernando-Ayuso, Javier Univ Politecn Madrid Dept Fis Aplicada Escuela Tecn Super Ingn Aeronaut Plaza Cardenal Cisneros 3 E-28040 Madrid Spain Univ Tokyo Grad Sch Engn Dept Aeronaut & Astronaut Bunkyo Ku 7-3-1 Hongo Tokyo 1138656 Japan

A series to compute the collision probability of two spheres under the assumption of short encounter has been derived. It is valid for both Gaussian and non-Gaussian distributions of the position. In the particular case of a Gaussian distribution, the use of Hermite polynomials yields a simple form for the series. The region in which the parameters of the problem (probability density function of the relative position, relative position of the spheres, and size of spheres) define cases of practical interest has been carefully defined. A sampling set of 244 cases in this region has been chosen. On this sampling set, a comparison between this series and previous algorithms has been performed for the Gaussian case. This series is faster than any other algorithm in every case. Numerical evidence strongly suggests that if the series for the Gaussian case is truncated when the last term is smaller than the computed probability times a tolerance of 0.1 then the last term is an upper bound for the error.

关键词： Derelict Satellites Electrodynamic Tether Numerical Integration Earth probability density functions Graveyard Orbit Space Stations Space Debris Artillery Envisat

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Efficient successive reanalysis technique for engineering structures

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AIAA JOURNAL 2006年第8期44卷 1883-1889页

作者： Bae, Ha-Rok Grandhi, Ramana V. Canfield, Robert A. Wright State Univ Dept Mech & Mat Engn Dayton OH 45435 USA USAF Inst Technol Wright Patterson AFB OH 45433 USA

Engineering structural design requires many simulations of the structural system after modifications are made to the initial structure. The computational cost of these repetitive simulations can be prohibitive in many engineering applications, such as optimization, reliability analysis, and so forth. In this work, the successive matrix inversion method is improved to include the capability to update not only the inverse of the modified stiffness matrix, but also the modified system response vector. This is done by introducing an influence vector storage matrix and a vector-updating operator that makes it possible to perform sequential reanalyses. The improved successive matrix inversion method has a wider applicable range of modification than the original method. The applicability of the proposed successive matrix inversion method is demonstrated with two popular engineering problems: sensitivity analysis and reliability analysis of an aircraft wing structure.

关键词： Finite Element Analysis Structural System Structural Design Aircraft Wings Sensitivity Analysis probability density functions Elastic Modulus Trusses Structural Reliability Monte Carlo Simulation

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Effects of unmixedness in piloted-lean premixed gas-turbine combustors

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JOURNAL OF PROPULSION AND POWER 1998年第6期14卷 967-973页

作者： Barnes, JC Mellor, AM Vanderbilt Univ Dept Engn Mech Nashville TN 37235 USA

The characteristic time model (CTM) represents the dominant physical processes related to combustor performance in terms of characteristic times. Properly formulated, these characteristic times will correlate effects of variations in combustor geometry, fuel characteristics, and operating conditions. Here, a CTM for NOx emissions is used to investigate the sensitivity of NO formation in piloted-lean premixed combustor to fuel/air unmixedness. The CTM analysis presented here also suggests an experimental method of evaluating premixed performance under fired conditions that is discussed in a companion paper.

关键词： Gas Turbine Combustor Lean Premixed Combustor Pilot Adiabatic Flame Temperature Fuel Air Mixture Flameholder probability density functions CFD Fluid Mechanics Flow Conditions

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CLUTTER EFFECT ON THE MISS DISTANCE OF A RADAR HOMING MISSILE

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JOURNAL OF GUIDANCE CONTROL AND DYNAMICS 1988年第4期11卷 336-342页

作者： MIWA, S IMADO, F KURODA, T MITSUBISHI ELECT CORP DEPT MECH SYST & TECHNOLCENT RES LABTOKYOJAPAN

When the target Doppler frequency in a radar homing missile crosses the main lobe clutter spectrum at the terminal phase of its flight, a large miss distance is induced. This paper presents the quantitative analysis on this clutter effect using a program named SAMS (Statistical Assessment of Missile Systems), which is a hierarchical and generalized version of the SLAM (Statistical Linearization Adjoint Method). A homing missile is represented by triple time constants, a limiter, a second-order missile airframe, and proportional navigation. The main lobe clutter is imposed on to this system along with the target random maneuver, glint, fading, and receiver noise. By processing the covariance propagation of the system equation and the adjoint system, the miss distance and the contribution of each noise are calculated. The results reveal that the clutter effect is maximized if the target Doppler frequency begins to cross the main lobe clutter spectrum 2 s prior to the terminal time, and it is largely enhanced if the target random maneuver is combined. These effects are reduced, however, if the missile lateral acceleration capability is increased or the target lateral acceleration decreased. The radome effect is also analyzed by adding the related feedforward loop to the original system, which makes a considerable change in the miss distance. © 1988 American Institute of Aeronautics and Astronautics, Inc., All rights reserved.

关键词： Homing Missile RADAR Radomes Airframes Missile Systems Feedforward Proportional Navigation Power Spectral density Missile Guidance probability density functions

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