Ground vehicle doppler geolocation

This paper reports on the performance of a recently developed particle filter technique to locate a stationary push-to-talk (PTT) radio using the Doppler-shifted signal as observed by a single moving ground vehicle. The primary difficulty for single-sensor Doppler-based localization is that the solution is strongly dependent on the target's unknown original carrier frequency. This uncertainty allows many possible location estimates to correspond with the observations. Furthermore, the PTT carrier is observed to drift significantly over short time periods. This creates a dynamic, multimodal objective function and motivates the application of the particle filter solution. The technique's performance is demonstrated on real data collected by a slow-moving (10-40 mph) ground vehicle over a relatively short 0.5 km range. The location accuracies achieved are compared to the theoretical frequency of arrival (FOA) Cramer-Rao Lower Bound (CRLB) and with the more common two sensor frequency difference of arrival (FDOA) solution.