Demonstrating Single Element Null Steering Antenna Direction Finding for Interference Detection

Use of Global Navigation Satellite Systems (GNSS) in safety of life applications such as aircraft navigation, railway control and autonomous vehicles is increasing as these technologies become more necessary or mainstream. To serve these applications, GNSS must provide high integrity, even in the face of deliberate attacks such as spoofing. The Stanford dual polarization antenna (DPA) is a technology that uses a single patch antenna but with two feeds to examine both left and right hand circularly polarized (LHCP and RHCP, respectively) signals. Proper design and installation allows the DPA to use polarization of the incoming signal to determine direction of arrival (DOA) and elevation. These measures can be used to discriminate a genuine from a bogus broadcast. The technology can also null out some interference signals. This paper examines the continued development and field tests of our DPA. Test with genuine on-air signals have shown the ability to determine DOA and elevation Field test in on-air spoofing and jamming conditions were also conducted. These scenarios allow us to demonstrate the performance of the DPA processing, DOA and elevation estimates.