The estimation algorithm of ballistic missile state based on early warning satellite

The early warning satellite can measure only the line of sight (LOS) direction, which results in poor observability of the missile motion. Consequently, the maximum likelihood estimation problem is very ill conditioned. To deal with this problem, the levenberg-Marquardt algorithm is utilized. Using partial priori information, the missile altitude and speed at the initial point, as an extra pseudomeasurement, the modified maximum likelihood (MML) algorithm is presented to estimate the state of ballistic missile. Monte Carlo simulation studies on some typical scenarios were performed, and the results indicate that the estimation errors are commensurate with the theoretical lower bounds, thus illustrating that the proposed estimator is efficient.