Session A2: Next Generation Satellite Navigation Technology

Fast Spreading Code Optimization Under Doppler Effects
Alan Yang, Tara Mina, and Grace Gao, Stanford University
Location: Seaview Ballroom
Date/Time: Wednesday, Jan. 24, 11:26 a.m.

Peer Reviewed

In this work, we propose a method for optimizing the auto-and cross-correlation properties of binary spreading codes while ensuring robustness to the Doppler shift effects induced by satellite motion. In our approach, we minimize the expected value of the sum of squared auto- and cross-correlation sidelobes, where the expectation is taken over a suitably-chosen, possibly continuous, probability distribution over Doppler frequencies. We derive a fast and scalable bit-flip descent method, which is able to find Doppler-robust spreading code families with family sizes of 300 codes and code lengths of up to 5113 chips. We demonstrate our method using three case studies modeled after GPS, Lunar PNT, and LEO PNT applications.