Analysis of a High Accuracy Service for GPS based on JPL’s Global Differential GPS

n the current GNSS context with several constellations offering High Accuracy Services (HAS), wehave performed an analysis of a HAS for GPS based on JPL’s Global Differential GPS (GDGPS) system.The HAS provides corrections for Galileo and GLONASS also. The scenario being analyzed is presentlydelivering satellite corrections to users through the Internet, similarly to one style of access to GalileoHAS. The GDGPS-based HAS described in this research mainly consists of high-quality satellite orbit andclock corrections, with additional support for satellite code biases. Also under consideration are increasedsupport for satellite code biases, together with support for satellite phase biases to allow for precise pointpositioning with ambiguity resolution (PPP-AR). Corrections are provided in two parallel variations: onestream supporting GPS and Galileo, and the other supporting GPS and GLONASS. Each variation isprovided in two redundant instances for robustness, a total of four streams. Analysis of the quality ofthe corrections and of the PPP solutions based on these products attests to the quality of the corrections.PPP results show good performance, with PPP performance comparable to solutions generated basedon real-time CNES products, and better than solutions generated based on Internet-based Galileo HASproducts (obtained through Internet-based distribution). For instance, based on processing over 2,000independent three-hour datasets, both GDGPS-based HAS GPS+GAL streams, as well as the CNES stream,allow for 97% of datasets to achieve post-convergence horizontal rms below 20 cm, and 88% below 10 cm.Comparatively, 81% of Galileo HAS-based solutions have post-convergence horizontal rms below 20 cm,and 33% have rms below 10 cm. The results suggest a means of implementing a HAS based on GDGPSthat might serve as an augmentation to GPS, Galileo, and GLONASS.