An Improved TCAR Based on the Optimal Combination of Carrier Phase and Pseudo-range Observations

The core issue for high precision relative dynamic positioning application is how to fix integer carrier ambiguity fast and accurately. Traditional three carrier ambiguity resolution (TCAR) method find the suitable combination of carrier phase and pseudo-range observations using integer search traversal method, which make the lower success reliability for narrow-lane ambiguity resolution. In the analysis of the error characteristics of the combined observations, we introduce a new procedure to select the optimal combination of carrier phase and pseudo-range observations based on the minimum of total noise level, with real-time estimating accurately and mitigating even eliminating the impact of ionospheric delay, successfully fixed three linearly independent combinations of the integer ambiguity, then determine the basic integer ambiguities. Finally, the performance of the improved TCAR in short-baseline condition is showed by processing the observations collected by two BeiDou triple-frequency receivers, the results show that, this method fix the integer ambiguities of double differenced extra-wide lane and wide line from single epoch, total noise level was decreased almost 15 %, with several epochs smoothing, the success reliability of basic ambiguities achieve 95 %, which is improved at least 30 % compare with traditional TCAR method.