A Method of Passive Location of the Returnable Spacecraft Beacon

Abstract

During the landing procedure of a recoverable spacecraft，measurement and control information、COSPAS/SARSAT system information and regional location information are often used. According to the deficiencies of above method，the long baseline TDOA technique is suggested. Firstly the principles of TDOA system and the solution of TDOA equations are proposed. The features of the beacon’s sinusoidal envelop are analyzed. High precision frequency estimation method based on modified Rife algorithm and TOA estimation method based on DTFT phase evaluation algorithm are suggested. Simulations on TDOA precision are given. Location precision distribution of the beacon is simulated. The stationary location error is less than 1km when the target range is less than 100km. When the square style of the receiving stations is applied，the dynamical tracking and filtering process is simulated. The results show that range error is less than 1km and azimuth error is less than 1minute during the tracking procedure. Finally the two-dimension velocity estimation method based on the FDOA information is analyzed.

Keywords

returnable spacecraft / beacon / passive location / time difference of arrival / frequency difference of arrival