Minimum Variance β Estimation with Dynamic Constraints

摘要

The degree to which the ballistic coefficient (beta) can be estimated from reentry metric data can be meaningfully analyzed with a sophisticated computer program which realistically models the problem and performs a proper error analysis of the estimation procedure. Such a program has been developed (at AFETR) and is being used to isolate the primary error sources in the beta estimation task. This computer program is additionally used to determine what success in beta estimation can be achieved with foreseeable instrumentation accuracies. Results are included that illustrate the effects on beta estimation from the following variations: (1) instrumentation measurement type and accuracy; (2) relative geometry between trajectory and observer; (3) arc length and minimum altitude of tracking; and (4) the magnitude of beta. The central thesis of the analysis presented in this report is that dynamic constraints can be used to advantage in the problem of estimating the trajectory and ballistic coefficient. The least squares, constrained solution takes advantage of the exercise of tracking geometry over a sufficiently long arc to estimate the trajectory parameters and beta. For a given set of tracking instrumentation, the enforcement of dynamic constraints throughout the entire trajectory should provide the maximum available information to the estimation process. (Author)