Cluster expansions in many-fermion theory. I - ''Factor-cluster'' formalisms.
Cluster expansions in many fermion system for calculating expectation values of observables with respect to dynamically correlated state vectors
Clark, J. W.↗
SEARCH · Search NASA
Results for “STATE VECTOR”
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Lunar Orbiter simple moon residuals
Charts of residual Doppler patterns from Lunar Orbiter state vector solutions
Hansen, T. J.↗
Saturn V navigation update.
Navigation state vector update effect on lunar mission completion capability for Saturn 5, emphasizing hardware and scheme errors and accelerometer failure
Obrien, R. M.↗
Earth-centered analytic abort program document. Volume 1 - User's manual
Earth centered abort program to generate optimal trajectories from specified preabort state vector to earth landing
R W Kehrman↗
Derivation of a general perturbation solution - Its application to determination of orbit
Analytical solution to three-body problems is applied to the problem of predicting the orbit of a lunar satellite and determining the orbit of a near-earth satellite. Using this solution, the state vector may be generated at any time without intermediate numerical extrapolation.
Born, G. H.↗
Massachusetts Institute of Technology third quarterly progress report, 1 August - 31 October 1969
Satellite state vector of position deviation and two velocity deviation components
Source record↗
Empirical Bayes estimation of observation error variances in linear systems
Kalman filter set for state vector and observation error variance estimation in discrete- time linear system, using empirical Bayes techniques
Born, G. H.↗
TBERR - Two-body error analysis program
Two-body error analysis computer program to evaluate resulting state vector and covariance matrix for orbiter after one coast and one burn maneuver
Muhonen, D. P.↗
Applications of generalized inverses to estimation in a dynamic system
Generalized matrix inverses application to estimation of state vector in dynamic control system, determining covariance matrix of estimator
Prochaska, B. J.↗
Orbital operations study. Appendix A: Interactivity analysis
Supplemental analyses conducted to verify that safe, feasible, design concepts exist for accomplishing the attendant interface activities of the orbital operations mission are presented. The data are primarily concerned with functions and concepts common to more than one of the interfacing activities or elements. Specific consideration is given to state vector update, payload deployment, communications links, jet plume impingement, attached element operations, docking and structural interface assessment, and propellant transfer.
Source record↗
Calculation of trajectories using constant and slowly varying functions
A method is presented for calculating trajectories for the restricted problem of three bodies which utilizes conic propagation of the state vector with frequency correction of position and velocity by means of a constant or slowly varying function. This method of calculating trajectories was applied to the planar circular restricted three body problem, the planar elliptic restricted problem, and the ephemeral restricted problem. Two methods (the refined method and the straight forward method) of determining the direction of the position correction are presented for the circular restricted problem and the elliptic restricted problem of three bodies. Only the straight forward method was used with the ephemeral restricted problem. The earth, the moon, and a space vehicle comprise the restricted three body model that is used.
Culpepper, B. K.↗
The estimation of the constituent densities of the upper atmosphere by means of a recursive filtering algorithm.
The structure of the upper atmosphere can be indirectly probed by light in order to determine the global density structure of ozone, aerosols, and neutral atmosphere. Scattered and directly transmitted light is measured by a satellite and is shown to be a nonlinear function of the state which is defined to be a point-wise decomposition of the density profiles. Dynamics are imposed on the state vector and a structured estimation problem is developed. The estimation of these densities is then performed using a linearized Kalman-Bucy filter and a linearized Kushner-Stratonovich filter.
Mcgarty, T. P.↗
Applications of generalized inverses to estimation in dynamic systems.
Generalized matrix inverses are used to obtain an estimation procedure for estimation of the state vector of a dynamic system. This sequential procedure is studied analytically with respect to the choice of an arbitrary vector. The covariance matrix of the estimator is determined and compared to the optimal Kalman type procedure. A numerical example illustrates the procedure and compares it to the optimal one.
Prochaska, B. J.↗
Recursive filter initialization.
Description of an initialization technique which partially accounts for the interrelation between the true-state vector errors when recursive filtering is applied in space navigation systems. The technique reduces the undesirable transient effects of the first few measurements and inhibits filter divergence when the interval between measurements is inordinately large. The key feature of this technique is the inclusion of the effect of a number of pseudo-measurements of certain orbital parameters into the initial covariance matrix. The pseudo-measurement technique has been shown to be useful when reinitialization of the error covariance matrix is required to prevent filter divergence.
Battin, R. H.↗
Application of modern control theory to the design of optimum aircraft controllers
The synthesis procedure presented is based on the solution of the output regulator problem of linear optimal control theory for time-invariant systems. By this technique, solution of the matrix Riccati equation leads to a constant linear feedback control law for an output regulator which will maintain a plant in a particular equilibrium condition in the presence of impulse disturbances. Two simple algorithms are presented that can be used in an automatic synthesis procedure for the design of maneuverable output regulators requiring only selected state variables for feedback. The first algorithm is for the construction of optimal feedforward control laws that can be superimposed upon a Kalman output regulator and that will drive the output of a plant to a desired constant value on command. The second algorithm is for the construction of optimal Luenberger observers that can be used to obtain feedback control laws for the output regulator requiring measurement of only part of the state vector. This algorithm constructs observers which have minimum response time under the constraint that the magnitude of the gains in the observer filter be less than some arbitrary limit.
Power, L. J.↗
Suboptimal stochastic controller for an n-body spacecraft
The problem is studied of determining a stochastic optimal controller for an n-body spacecraft. The approach used in obtaining the stochastic controller involves the application, interpretation, and combination of advanced dynamical principles and the theoretical aspects of modern control theory. The stochastic controller obtained for a complicated model of a spacecraft uses sensor angular measurements associated with the base body to obtain smoothed estimates of the entire state vector, can be easily implemented, and enables system performance to be significantly improved.
Larson, V.↗
Deorbit targeting
The navigation and control of the space shuttle during atmospheric entry are discussed. A functional flow diagram presenting the basic approach to the deorbit targeting problem is presented. The major inputs to be considered are: (1) vehicle state vector, (2) landing site location, (3) entry interface parameters, (4) earliest desired time of landing, and (5) maximum cross range. Mathematical models of the navigational procedures based on controlled thrust times are developed.
Tempelman, W. H.↗
The real-time acquisition and tracking program for the USNS Vanguard
The computer program for the real-time acquisition and tracking program uses a variety of filtering algorithms including an extended Kalman filter to derive real-time orbit determination (position-velocity state vectors) from shipboard tracking and navigation data. Results from Apollo missions are given to show that orbital parameters can be estimated quickly and accurately using these methods.
Brammer, R. F.↗