Improvement of GPS Relative Positioning Accuracy by Using SNR

Interference and multipath are the main error sources of Global Positioning System (GPS) measurement in engineering surveying. This paper describes an algorithm that mitigates specular multipath as well as interference in GPS differential carrier phase measurement by using signal-to-noise ratio (SNR). The focus is on multipath because it accounts for most of the total error budget in differential carrier phase measurement. The algorithm is demonstrated on static platforms in severe multipath environments. The accuracy is tested with predefined displacements on an X-Y-Z stage, and the experimental results are compared to sidereal day-to-day repeatability. The data sets used for investigation are six-epoch measurements, and the accuracy of the six-epoch solution is shown.