Data Compression for Emitter Location

Locating emitters by cross-correlating received signals to compute their time-difference-of-arrival (TDOA) and the frequency-difference-of-arrival (FDOA) requires that signal data received at one platform be transferred to the other platform. Often the data link used has insufficient bandwidth to accomplish the transfer within the time requirement, and therefore use of data compression is needed. This paper outlines a useful progression in compression techniques from those that consider only mean square error to those that consider the true impact on the estimated TDOA/FDOA accuracy. Within this context, specific results are presented for two compression approaches for TDOA/FDOA systems. The first is the application of block-adaptive quantizers (BAQ) to the real and imaginary parts of the complex baseband signal to be transferred. The second uses a wavelet transform together with an adaptively allocated set of quantizers; also, certain wavelet coefficients can be eliminated with lower impact on the TDOA/FDOA accuracy than expected from a mean-square quantization point of view.