Naive Beamforming for Multi-Element Antenna GNSS Receiver

Abstract

Antenna array beamforming is a useful technique for GNSS receivers for signal-to-noise improvement and multipath and interference mitigation. Any conventional beamforming algorithm implementation is complicated. The algorithm adds together different antenna signals with expected weights. To calculate the weights, it requires antenna elements' RP calibrations, receiver attitude determination and wide data channels between the CRPA and the receiver. A naive beamforming approach is described in this paper. It doesn't calculate expected weights for the desired beamforming direction. The algorithm directly estimates phase differences of the signals and use the estimations to focus them. As result, the proposed algorithm doesn't have the described disadvantages of the regular beamforming. Experimental results are presented. The used mock-up is based on a seven-element L1-band convex antenna array and a Xilinx Zynq-based navigation receiver. It is shown by the experiments, that beamforming allows to increase channel SNR about 7–8 dB. As result, root-mean-square pseudorange errors decrease 2-2.5 times.