Accession Number : ADP009114
Title : A Comparison of GPS Broadcast and DMA Precise Ephemerides,
Corporate Author : NATIONAL INST OF STANDARDS AND TECHNOLOGY BOULDER CO TIME AND FREQUENCY DIV
Personal Author(s) : Weiss, Marc A. ; Petit, Gerard ; Shattil, Steve
Report Date : 02 DEC 1993
Pagination or Media Count : 14
Abstract : We compare the broadcast ephemerides from Global Positioning Satellites (GPS) to the postprocessed ephemerides from the Defense Mapping Agency (DMA). We find significant energy in the spectrum of the residuals at 1 cycle/day and higher multiples. We estimate the time variance of the residuals and show that the short term residuals, from 15 min, exhibit power law processes with greater low frequency perturbations than white phase modulation. We discuss the significance of these results for the performance of the GPS Kalman filter which estimates the broadcast orbits.
Descriptors : *EPHEMERIDES, *NAVIGATION SATELLITES, CYCLES, ESTIMATES, LOW FREQUENCY, MODULATION, PERTURBATIONS, PHASE MODULATION, RESIDUALS, TIME, GLOBAL POSITIONING SYSTEM, KALMAN FILTERING.
Subject Categories : Spacecraft Trajectories and Reentry
Distribution Statement : APPROVED FOR PUBLIC RELEASE