GLONASS Ambiguity Resolution Method Based on Long Baselines and Experimental Analysis

Frequency division multiplexing of GLONASS signals causes interfrequency bias(IFB) in the receiving equipment. IFB significantly prevents GLONASS ambiguity resolution and limits the accuracy and reliability of GLONASS positioning and orbit determination. Therefore, we present a new method for GLONASS ambiguity resolution. Firsly, it weakens the influence of inter-frequency code bias, and widelane ambiguities are calculated directly based on the wide-lane combined observations. Then, according to the range of inter-frequency phase bias rate, a step-by-step search schedule is designed to remove the im-pacts of inter-frequency phase bias on wide-lane and narrow-lane ambiguities. Finally, the ambiguity resolution can be achieved successfully. An IGS experiment network is carried out to verify the validity of this method. Experimental results show that the maximum, minimum and mean success rate of fixed ambiguities within the month were 95.4%, 88.8% and 93.45%, respectively. After ambiguity resolution, the repeatability and root mean square error (RMSE) of N, E, U components were improved; especially for E component, the repeatability and RMSE were improved 20% and 14%, respectively. This proves the validity of this method.