Single-Epoch Integer Ambiguity Resolution with GPS-GLONASS L1-L2 Data

The effectiveness of single-epoch integer ambiguity resolution, which provides centimeter-level relative positioning in real-time, is a function of the number, quality and type of carrier phase measurements available. We apply the Local-Minima Search (LMS) method epoch-by-epoch to GPS-GLONASS dual frequency carrier phase measurements taken over 2, 9 and 18 km baselines. While the application of LMS to GPS dual frequency measurements alone works quite well over these baselines, the addition of GLONASS improves the search success rate and greatly enhances the ability to validate the resulting solutions. At both 9 km and 18 km the LMS success rate was nearly 100%, when using the combined set of carrier phases. The addition of GLONASS reduced the average search ratio by more than 1/3 over the ratio obtained using only GPS phases. A fuller GLONASS constellation will certainly improve on these results.