Distributed GPS Beamforming with Low-Cost Software Defined Radios
Wilbur L. Myrick, ENSCO, Inc.
Location: Grand Ballroom F
Date/Time: Thursday, Feb. 1, 9:05 a.m.
This paper describes a distributed GPS beamforming system with low-cost SDRs lacking an external hardware interface for synchronization. In particular, this GPS beamforming system consists of four COTS SDRs and GPS active patch antennas. The process of extracting carrier phase measurements for both SDR clock drift information as well as GPS carrier phase differences to explore GPS beamforming is discussed. We show that carrier phase extraction from each SDR operating with a limited processing bandwidth of 2.4 MHz provides enough information to support asynchronous GPS beamforming. We explore leveraging GPS to support both distributed sensor synchronization and beamforming when an external synchronization hardware interface is unavailable for inexpensive COTS SDRs like the RTL-SDRs. The GPS receiver processing chain is discussed leveraging MATLAB to support offline asynchronous GPS beamforming exploration.