System and method for cumulant-based geolocation of cooperative and non-cooperative rf transmitters

Abstract

A transmitted signal's higher order statistics of temporally dependent waveforms are exploited to geolocate low power signals. The geolocation is independent of the characteristics or encoded data of the transmitted waveform. The method uses spatial fourth order cumulants or spatial second order moments in a Blind Source Separation and generalized eigenvalue decomposition to determine unique matrix pencil eigenvalues and eigenvectors. The eigenvectors provide are orthogonal to the steering vector of the transmitted signal save one, which represents the steering vector. This property is used to determine Steering vectors, AoA or geolocation. The receiver includes a multi-element array and does not need a priori knowledge of the transmitted signal source to geolocate the target transmitter. The methods and apparatus for geolocation does not require typical demodulation.

1 - 36 . (canceled) 
   
   
       37 . In a receiver including an antenna with a plurality of antenna elements for receiving a signal comprised of a plurality of symbols and a digitizer for providing a bit stream from the received symbols, the improvement comprising means for determining a temporal dependence between bits of the bit stream. 
   
   
       38 . The receiver of  claim 37  wherein the means for determining a temporal dependence further comprises means for determining a matrix pencil eigenvalue for at least a portion of the signal. 
   
   
       39 . The receiver of  claim 38  wherein the means for determining a temporal dependence further comprises means for determining the generalized eigenvalue decomposition of said matrix pencil eigenvalue. 
   
   
       40 . The receiver of  claim 39  wherein the means for determining a temporal dependence further comprises means for estimating a steering vector from the matrix pencil eigenvalue. 
   
   
       41 . The receiver of  claim 40  further including means for determining the angle of arrival of the signal. 
   
   
       42 . The receiver of  claim 41  wherein the angle of arrival is determined based on the temporal dependence. 
   
   
       43 . The receiver of  claim 42  wherein the means for determining the angle of arrival further comprises means for determining the angle of arrival as a function of said steering vector. 
   
   
       44 . The receiver of  claim 38  wherein the means for determining the matrix pencil eigenvalue comprises a means for determining a higher-order statistic of the received signal. 
   
   
       45 . The receiver of  claim 44  wherein the higher-order statistic is a fourth-order cumulant of the received signal. 
   
   
       46 . The receiver of  claim 37  wherein the signal has a received SNR less than 0 dB. 
   
   
       47 . The receiver of  claim 37  wherein the signal has a SNIR less than 0 dB at the receiver. 
   
   
       48 . The receiver of  claim 37  wherein the signal has a SNIR less than −6 dB at the receiver. 
   
   
       49 . The receiver of  claim 37  wherein the bits of the bit stream are successive bits in the bit stream. 
   
   
       50 - 62 . (canceled)