GPS-based orbit determination and point positioning under selective availabilitySelective availability (SA) degrades the positioning accuracy for nondifferential users of the GPS Standard Positioning Service (SPS). The often quoted SPS accuracy available under normal conditions is 100 m 2DRMS. In the absence of more specific information, many prospective SPS users adopt the 100 m value in their planning, which exaggerates the error in many cases. SA error is examined for point positioning and dynamic orbit determination for an orbiting user. To minimize SA error, nondifferential users have several options: expand their field of view; observe as many GPS satellites as possible; smooth the error over time; and employ precise GPS ephemerides computed independently, as by NASA and the NGS, rather than the broadcast ephemeris. Simulations show that 3D point position error can be kept to 30 m, and this can be smoothed to 3 m in a few hours.
Document ID
19920034312
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Bar-Sever, Yoaz E. (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)
Wu, Sien-Chong (JPL Pasadena, CA, United States)
Date Acquired
August 15, 2013
Publication Date
January 1, 1990
Subject Category
Space Communications, Spacecraft Communications, Command And Tracking