Tdoa/fdoa technique for locating a transmitter

Abstract

A process for locating a transmitter in which the signal is received by first and second receivers and then processed by respective analog to digital converters and filtered to yield first and second digital signals. There is relative motion between at least one of the receivers and the transmitter. A compression process local to the first receiver compresses the first digital signal. The result of the compression process is transmitted to a cross-correlation unit which is local to the second receiver and coupled also to receive the second digital signal. Locally to the first receiver, correction factors for the solution to the cross-correlation function are determined and transmitted to a correction unit at the second receiver site which applies the correction factors to the solution of the cross-correlation function. The location of the transmitter is determined based on time difference of arrival and frequency difference of arrival results output from the correction unit. If there is no relative motion between the transmitter and any receiver, then three receivers are necessary to locate the transmitter. The outputs are analog to digital converted and filtered to yield first, second and third digital signals. A compression process at the first receiver site compresses the first digital signal. The compressed signal data is transmitted to convolution units local to the second and third receivers and convolved with the second and third digital signals, respectively. Then correction factors for both convolution units are determined local to the first receiver and transmitted to correction units at both the second and third receiver sites. The location of the transmitter is then determined based on two time difference of arrival results.