An anti-jamming enhanced GNSS receiver with beamforming capability can forms a beam toward each satellite direction and acquires and tracks the GNSS satellite signal (Kaplan & Hegarty 2006). At this time, the phase error of each channel is caused by various sources such as an array antenna, RF devices, local oscillators and ADCs, which degrades the performance of beamforming. RF devices, local oscillators, and ADCs can be designed with minimal hardware phase error. However, as array antennas have different phase errors depending on the azimuth and elevation angles, so it is difficult to reduce the phase error in all directions. In this paper, the phase errors of various small array antennas are evaluated by comparing actual measured phase values with the theoretical values calculated by antenna geometry. And the effect of beamforming performance caused by the phase error is analyzed.

Keywords: array antenna, beamforming, anti-jamming