Characteristics and Applications of Precise GPS Clock Solutions Every 30 Seconds

Abstract

Using carrier phase and pseudorange data from a small network of globally distributed GPS receivers with precise time references, we are able to estimate GPS clock parameters every 30 s, with subdecimeter accuracy, in a computationally efficient manner. The accuracy obtained is a factor of 100 to 1000 times better than that of clocks in the broadcast navigation message, and allows post-processing of high-rate single-receiver kinematic GPS data with few-centimeter-level precision when used in conjunction with precise GPS orbits. The amplitude of the daily clock variability is typically 24 m for satellites affected by Selective Availability (SA). Temporal variations are well modeled by an autocorrelation function ρ = exp(— d2 / 2τ2) with τ ∼ 106 s.