Single receiver emitter geolocation based on signal periodicity with oscillator instability

We propose a method for localizing a stationary emitter, not necessarily cooperative, using a single moving receiver based on time of arrival (TOA) measurements. The sensor intercepts the incoming signal at different locations along its trajectory, thus, effectively creating an array of spatially separated sensors. This manuscript presents the method and its performance in the presence of noise and oscillator instability. The proposed method provides a few advantages over the traditional multi-sensor TOA method. These include the economic aspect of using a single receiver instead of several ones, synchronization between stations is not required since only a single sensor is used, on line optimization of the emitter-sensor geometry in order to improve performance (path design, number of data collection points, etc.), and finally, there is no requirement to transmit data between sensors. The method is applicable to any signal as long as it includes a portion that appears periodically such as a synchronization sequence, or a signal whose transmission time intervals are known, even if they are not identical. We derive the Cramér-Rao lower bound, perform small error analysis for the algorithm, and corroborate the results with simulations. We show that reasonable localization results can be obtained under realistic conditions.