GAPS: The GPS Analysis and Positioning Software - A Brief Overview

Rodrigo F. Leandro, Marcelo C. Santos, and Richard B. Langley

Abstract:	Precise Point Positioning (PPP) is one of the existing techniques for determining point coordinates using a GPS (Global Positioning System) receiver. In this technique, observations produced by a single receiver are used to determine the three coordinate components, as well as other parameters, such as the receiver clock error and total neutral atmosphere delay. The technique is said to be precise" because precise information, such as satellite orbit and clock errors, is used in the data processing. More than that, it can also be called precise because the resulting position coordinates are precise (and accurate). The idea behind our present work is that PPP can be used not only for positioning, but for a variety of other tasks, such as signal analysis. The fact that the observation model used in this technique has to take into consideration the several effects present in GPS signals, and that observations are undifferenced (there are no differences between receivers nor between satellite measurements), makes PPP a powerful data analysis tool which is sensible to a variety of parameters. The PPP application developed at UNB, which is called GAPS (GPS Analysis and Positioning Software), has been designed and built in order to be used as a tool for determining parameters other than position, receiver clock error and neutral atmosphere delay. These other estimated parameters include ionospheric delays, code biases, satellite clock errors, and code multipath among others. GAPS is a veritable “Swiss Army knife” for GPS data analysis. In all cases, the procedures were developed in order to be suitable for real-time as well as postprocessing applications. Each of the data analysis products listed above will be overviewed in this paper."
Published in:	Proceedings of the 20th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2007) September 25 - 28, 2007 Fort Worth Convention Center Fort Worth, TX
Pages:	1807 - 1811
Cite this article:	Leandro, Rodrigo F., Santos, Marcelo C., Langley, Richard B., "GAPS: The GPS Analysis and Positioning Software - A Brief Overview," Proceedings of the 20th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2007), Fort Worth, TX, September 2007, pp. 1807-1811.
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