PPP Technique Analysis Based on Time Convergence, Repeatability, IGS Products, Different Software Processing, and GPS+GLONASS Constellation

In recent years interest has increased for precise point positioning (PPP), which provides an alternative to precise relative processing because of its potential as a reliable absolute positioning technique. PPP technique takes advantage of satellite orbit and clock products obtained from the global infrastructure of permanent stations. As a result, PPP requires only one dual-frequency, carrier-phase global positioning system (GPS) receiver on the client side and, thus, avoids the expensive and logistic difficulties of deploying a network of global navigation satellite system (GNSS) receivers around survey areas or in isolated places, such as the Arctic or less populated areas. The broad question of the place of PPP in the future spectrum of space geodetic measurement techniques is addressed in this study by investigating specific aspects of PPP. These aspects involve the following: (1) the time convergence solution in coordinates and accuracy; (2) the observational time required to guarantee the absolute character of the coordinates; (3) the coordinate variations by using rapid and ultrarapid International GNSS Service (IGS) orbits and clock files compared with the final IGS files, which is a useful test for real-time or near-real-time possible users; (4) the comparison of coordinate differences obtained in the postprocessing of daily observation receiver independent exchange (RINEX) files using different software [BERNESE v5.0 along with the four programs in the Precise Point Positioning Software Centre project; Automatic Precise Positioning Service (APPS), Canadian Spatial Reference System Online Global GPS Processing Service (CSRS-PPP), GPS Analysis and Position Software (GAPS), and Magic Global Navigation Satellite System (MagicGNSS) (GMV)]; and (5) the possibilities of the GPS+GLONASS constellation to reduce the convergence time solution and to improve the accuracy of the solution. Some of these five aspects have been partially analyzed in other papers, but this study analyzes these aspects as a whole. Daily observation files from eight IGS stations were analyzed from January 1, 2010, to January 10, 2010. The results offer a complete perspective of the PPP technique, its future prospects, and its current limitations in static positioning.
This study presents the preliminary results of the Spanish Science and Innovation Directorate project number AYA2010-18706.