Null steering approach with minimized PCV and GD for large aperture vertical antenna arrays

A novel null-steering method that minimizes the effect of radio frequency interference (RFI) and the effect of antenna phase center variation (PCV) and group delay (GD) is proposed. PCV and GD are important to characterize for global navigation satellite system (GNSS) antenna arrays used in satellite based landing architectures, since they directly affect the pseudo-range and accumulated Doppler observables. The proposed method is denoted as the Beam Subtraction method (BS). The BS method is compared against a conventional null-steering (CNS) method applied to a large aperture antenna array. Simulation results reveal noticeable improvement in both the PCV and GD curves as a function of azimuth and elevation angles when using the BS method compared to the CNS thus reducing the error on the range measurements as well as improving system availability in the presence of RFI. Index Terms--Group delay, multipath limiting antenna, null steering, phase center variation.