Accession Number : AD0717108

Title :   On-Line Parameter Updating for Mars Stratosphere and Troposphere Using Minimal Measurements,

Corporate Author : RENSSELAER POLYTECHNIC INST TROY N Y DEPT OF MECHANICAL ENGINEERING

Personal Author(s) : Duke,J. C. ; Shen,C. N.

Report Date : 1970

Pagination or Media Count : 36

Abstract : A technique is developed for on-board computation of the Mars atmospheric parameters ahead of an entry vehicle based upon discrete measurements of density and temperature gradient utilizing a maximum likelihood sequential estimation scheme. An atmospheric model suitable for describing both adiabatic and isothermal atmospheric regions has been derived. A rapid estimation scheme is introduced which permits a rapid reevaluation of the covariance matrix of the atmospheric parameters when passing through a changing atmospheric environment. A parameter transition detection scheme is developed which is suitable for determining a region of atmospheric alteration which cannot be known prior to atmospheric entry. A digital computer evaluation demonstrates the rapid estimation scheme is clearly superior to standard Kalman filtering throughout both the stratosphere and troposphere.

Descriptors :   (*MARS(PLANET), ATMOSPHERE MODELS), (*ATMOSPHERE ENTRY, DATA PROCESSING), MATHEMATICAL PREDICTION, MATRICES(MATHEMATICS), DENSITY, ATMOSPHERIC TEMPERATURE, STRATOSPHERE, TROPOSPHERE, TEST METHODS, SEQUENTIAL ANALYSIS

Subject Categories : Astrophysics
      Spacecraft Trajectories and Reentry

Distribution Statement : APPROVED FOR PUBLIC RELEASE