Pseudorange smoothing by carrier phase – an analysis of the tecnique

Abstract

Baseline positioning with carrier phase observations provide the best GPS results, however these observations require ambiguities fixing. On the other hand, code pseudorange positioning are not ambiguous, but the accuracy is not enough for the most part of the applications because it gives some meters accuracy. The pseudorange smoothing is a process provides intermediary accuracy, in other words, the accuracy is not so good as the carrier phase observations and is better then pseudorange observations alone. The idea of smooth pseudorange by carrier phase is to combine phase (mm level) and code (m level) observations. In principle the more data are used in smoothing more accurate is the positioning, and no resolution ambiguity is necessary. The objective of this work is to explore the pseudorange smoothing technique showing its fundamental principle and its positioning accuracy. Observations from absolute positioning was smoothed with L1 alone and with both carriers phase (L1 and L2). The processed results showed more precision in positioning with pseudorange smoothed than original pseudorange from code. In the most part of experiments the pseudorange from smoothing process are more accurate and more precise than pseudorange from L1 smoothed and original code. In baseline mode results showed accuracy better than 1 meter using pseudorange smoothed.