GPS Multipath Mitigation Assessment of Digital Beam Forming Antenna Technology in a JPALS Dual Frequency Smoothing Architecture

摘要

The Joint Precision Approach and Landing System (JPALS) is the U.S. Department of Defense's next generation landing system. A key challenge for the JPALS is achieving required accuracy and integrity in the presence of jamming and with ground station installations in poor multipath conditions. In this paper we consider two potential JPALS multipath mitigation technologies: Dual-Frequency Smoothing (DFS) differential GPS (DGPS) and digital beam-forming (DBF) with controlled reception pattern antennas (CRPAs). To perform a controlled assessment of different antenna and signal processing alternatives, we used a simulated diffuse ground multipath model along with a detailed anti-jam receiver signal processing model. The simulated code and carrier multipath errors were used to generate elevation angle-dependent statistical models that we used for comparative availability assessments. The combination of DBF and DFS algorithms yields substantial improvement in ground multipath errors compared to fixed-gain antennas, with a corresponding improvement in overall system availability.