Abstract
In this contribution, we study the phase-only ambiguity resolution and positioning performance of GPS for short baselines. It is well known that instantaneous (single-epoch) ambiguity resolution is possible when both phase and code (pseudorange) data are used. This requires, however, a benign multipath environment due to the severe effects multipath has on the code measurements. With phase-only processing, one would be free from such severe effects, be it that phase-only processing requires a change in receiver-satellite geometry, as a consequence of which it cannot be done instantaneously. It is thus of interest to know how much change in the relative receiver-satellite geometry is needed to achieve successful phase-only ambiguity resolution with correspondingly high precision baseline solutions. In this contribution, we study the two-epoch phase-only performance of single-, dual-, and triple-frequency GPS for varying time spans from 60 s down to 1 s. We demonstrate, empirically as well as formally, that fast phase-only very-precise positioning is indeed possible, and we explain the circumstances that make this possible. The formal analyses are also performed for a large area including Australia, a part of Asia, the Indian Ocean, and the Pacific Ocean. We remark that in this contribution "phase-only" refers to phase-only measurements in the observation model, while the code data are thus only used to compute the approximate values needed for linearizing the observation equations.
Highlights
In this contribution, we study, empirically and formally, the phase-only ambiguity resolution and positioning performance of single, dual, and triple-frequency Global Positioning System (GPS)for short baselines
Lower than 0.12 cycles approximately corresponds to an integer least-squares (ILS) ambiguity success rate (ASR) larger than 99.9%, which is lower bounded by the integer bootstrapping (IB) ASR [17]
Using different frequency combinations and time spans between the two epochs, the ambiguity resolution and positioning performances were evaluated with 1 Hz data collected from two baselines in Perth, Australia, based on both formal and empirical analysis
Summary
We study, empirically and formally, the phase-only ambiguity resolution and positioning performance of single-, dual-, and triple-frequency Global Positioning System (GPS). We keep the integer ambiguities in the phase-only model and use the change in receiver-satellite geometry to enable ambiguity resolution. This principle was first introduced in [3]. In this study, based on single-, dual-, and triple-frequency phase signals of the current GPS constellation, we evaluate the phase-only ambiguity resolution and positioning performance using two epochs separated by different time spans.
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