Reference Assisted TDOA Computation for On-Off Keyed Signals

This document considers the use of a partially known prototype signal to enhance the time difference of arrival TDOA computation for an On-Off Keyed OOK signal. It is shown through analysis and simulation that this approach can achieve a considerable reduction in the SNR threshold at which an acceptable rms TDOA spread can be achieved. For a signal transmitted with a carrier frequency that is stable within each observation interval, the threshold improvement can be in excess of 10 dB for a signal of practical interest. A similar degree of improvement was also observed for a signal with a carrier that exhibited frequency drift of up to 0.5 Hz within a 1.5 second interval. Analysis and simulation results are shown to be consistent with computations performed on data acquired from real transmitters.