Performance Analysis of the GNSS Instantaneous Ambiguity Resolution Method Using Three Collinear Antennas

Attitude determination technology based on the Global Navigation Satellite System (GNSS) has been widely studied due to its low cost and no accumulation of errors. The essential task of attitude determination using GNSS is to estimate the pointing vector of the baseline. However, when the user is located in a complex urban canyon environment, the success rate of ambiguity will be significantly reduced, resulting in inaccurate attitude determination results. This article presents improvements to existing methods for ambiguity resolution using collinear antennas. The collinear receiver system is built with low-cost commercial antennas to verify the method’s performance. Results indicate a success rate of over 68% with just four satellites, demonstrating significant improvement over the traditional least-squares ambiguity decorrelation adjustment (LAMBDA) method. This method reduces operation time while maintaining a high success rate, with a potential reduction of up to three orders of magnitude compared to the baseline-constrained LAMBDA (CLAMBDA) method. The method also exhibits potential anti- multipath capability, reducing root mean squared error (RMSE) of the pointing vector coordinate component by 60.3%, 87.5%, and 94.2% in the urban canyon environment with significant multipath effects. These results demonstrate the practical effectiveness and potential of the method for ambiguity resolution in challenging environments.