Toward decimeter Topex orbit determination using GPSSeveral practical aspects of precision GPS-based Topex orbit determination are investigated. Multipath signals contaminating Topex pseudorange data are greatly reduced by placing the GPS antenna on a conducting backplate consisting of concentric choke rings to attenuate signals coming in from the Topex horizon and below, and by elevating it on a boom to keep it well above all reflecting surfaces. A proper GPS antenna cutoff view angle is chosen so that a sufficient number of GPS satellites with good geometry are in view while reception of reflected signals is minimized. The geometrical strength of the tracking data is optimized by properly selecting GPS satellites to be observed so as to provide data with moderate continuity, low PDOP, and common visibility with ground tracking sites. The tracking performance is greatly enhanced when three complementary sites are added to the minimum ground tracking network consisting of the three NASA DSN sites.
Document ID
19900059706
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Wu, Sien-Chong (Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Yunck, Thomas P. (Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Hajj, George A. (JPL Pasadena, CA, United States)
Date Acquired
August 14, 2013
Publication Date
January 1, 1990
Subject Category
Space Communications, Spacecraft Communications, Command And Tracking