Single-frequency integer ambiguity resolution enabled GPS precise point positioning

Abstract

High-precision (centimeter-level) real-time kinematic precise point positioning (PPP-RTK) becomes feasible when using precise corrections, as received from a regional Continuously Operating Reference Station network. These network corrections comprise (biased) satellite clocks, (biased) satellite phase biases, and ionospheric delays, where the latter ones are interpolated to the approximate location of the PPPRTK receiver. Thus far, very fast PPP-RTK integer ambiguity resolution performance has been reported based on dual-frequency Global Positioning System (GPS) data. The availability of ionospheric corrections enables one to carry out PPP-RTK using a single-frequency receiver. Despite that single-frequency integer ambiguity resolution based on a single epoch of data cannot often be successful, fast integer ambiguity resolution is possible when accumulating a short time span of data, assuming that the ambiguities are time constant. In this paper, results of the performance of single-frequency PPP-RTK for both a high-grade geodetic receiver and a low-grade mass-market receiver are presented. The experiments have been conducted based on corrections determined from the GPS Network Perth. The conclusion reads that single-frequency PPP-RTK integer ambiguity resolution is feasible, even using a low-cost receiver: following an initialization time of about 4 min on average, the correct integers can be resolved in real-time, thus providing centimeter-level positioning.