Design and Performance Analysis of a Multi-Antenna Frequency-Locked GPS Attitude Determination Algorithm

Abstract

As autonomous research advances, the necessity for a functioning GPS receiver that can provide a full pose solution is insurmountable. This thesis proposes a novel coupling of phased array information into the tracking and navigation software of a GPS software-defined receiver. Specifically, the receiver is designed to track the spatial phase of the antenna array with the added restriction that it must also be able to estimate this spatial phase with only a frequency lock of the signal (i.e. a phase lock is not required). It is designed based on the advancements in GPS tracking architectures, namely vector processing, and the subsequent under utilization of all the information a phased array can offer. The proposed coupling of a phased array into the GPS architecture allows for both beamforming as well as attitude determination. This greatly enhances the robustness of a GPS receiver and allows for accurate attitude estimates even at low GPS signal powers. The algorithm was evaluated using both correlator simulations in addition to signal simulations generated using the Skydel GNSS simulator. Monte Carlo simulations were performed, proving the efficacy and robustness of the proposed attitude estimation algorithm. Live-sky GPS data was also used to indicate the real-world capabilities of the system.