Strategies for high‐precision Global Positioning System orbit determination

TLDR

High‑precision GPS satellite orbit determination is essential for precise geodetic measurements and low‑Earth orbiter tracking. The study investigates various orbit determination strategies using 1985 GPS field experiment data. The authors employ multiday arcs, fine‑tuned solar‑pressure coefficients, and stochastic station zenith tropospheric delays to optimize orbit determination from GPS data. The optimized strategy yields orbit repeatabilities of 1.0–1.7 m, predicts 1.5–2.5 m accuracy 24 h beyond a 7‑day arc, and achieves baseline repeatabilities of 0.4–0.6 cm for 246‑km baselines and 0.6–2 cm for 1314‑km baselines, improving to 0.6 cm north and 2 cm for other components when combining carrier phase with pseudorange.

Abstract

High‐precision orbit determination of Global Positioning System (GPS) satellites is a key requirement for GPS‐based precise geodetic measurements and precise low‐Earth orbiter tracking. We explore different strategies for orbit determination with data from 1985 GPS field experiments. The most successful strategy uses multiday arcs for orbit determination and incorporates fine tuning of spacecraft solar pressure coefficients and stochastic station zenith tropospheric delays using the GPS data. Average rms orbit repeatabilities for five of the GPS satellites are 1.0, 1.2, and 1.7 m in altitude, cross‐track, and downtrack components, when two independent 5‐day fits are compared. Orbits predicted up to 24 hours outside a 7‐day arc show average rms component differences of 1.5–2.5 m when compared to independent solutions obtained with a separate, nonoverlapping 5‐day arc. For a 246‐km baseline, with 6‐day arc carrier phase solutions for GPS orbits, baseline repeatability is 2 parts in 10 8 (0.4–0.6 cm) for east, north, and length components and 8 parts in 10 8 for the vertical component. For a 1314‐km baseline with the same orbits, baseline repeatability is about 2 parts in 10 8 for the north component (2.5 cm) and 4 parts in 10 8 or better for east, length, and vertical components. When GPS carrier phase is combined with pseudorange, the 1314‐km baseline repeatability improves further to 5 parts in 10 9 for the north (0.6 cm) and 2 parts in 10 8 for the other components (2–3 cm).