Group Delay Evaluation for GNSS Adaptive Antenna Array

Abstract Beam forming processing of adaptive antenna introduces distortions of group delay. For high-precision GNSS applications, the distortions cannot be ignored. In order to solve the problem, an evaluating method of adaptive array group delay based on availability beam is proposed. This method consists of three steps: firstly, setting the available beamwidth of the antenna; secondly, configuring different interference scenarios and calculating the group delay variation within the available beamwidth for each scenario; finally, averaging group delay variations obtained across different scenarios to derive the mean group delay variation. This method is applied to evaluate the group delay performance of four typical planar arrays under interference conditions. Experimental results indicate that the uniform circular array is the optimal high-precision adaptive antenna configuration under interference conditions. Additionally, by setting an appropriate available beam threshold, the stability of the average group delay of the adaptive antenna can be improved. The method can quickly and effectively evaluate the group delay of the adaptive antenna, and the evaluation results can serve as a reference for the performance assessment of high-precision GNSS adaptive antennas.