Three Scanning Techniques for Deep Space Network Antennas to Estimate Spacecraft Position

Scanning movements are added to tracking antenna trajectory to estimate the true spacecraft position. The scanning movements are composed of harmonic axial movements of an antenna. This scanning motion produces power variations of the received signal, which are used to estimate spacecraft position. Three different scanning patterns (conical scan, Lissajous scan, and rosette scan) are presented and analyzed in this article. The analysis includes evaluation of the estimation errors due to random or harmonic variation of the antenna position and to random and harmonic variations of the power level. Typically, the estimation of the spacecraft position is carried out after completing a full scanning cycle. In this article, slidingwindow scanning is introduced, wherein the spacecraft position estimation is carried out in an almost continuous manner, which reduces estimation time by half.