is identified in task 208 in accordance with task 502 two or more pairs of hydrophones for each of the various possible ship 39 s velocity vectors are identified in some embodiments all available pairs of hydrophones are identified for each possible velocity vector in accordance with task 504 i q data from an early pulse on one receiver is correlated with i q data from a later pulse on another receiver hydrophone channel for all receiver vector separations each vector correlation yields an element of the complex correlation array the correlation array element is defined as i and j are a matrix row and column indices there are specific channel pairs associated with each position it will be understood that expressions 1 and 2 are for complex variables as a consequence a real and imaginary a matrix results in some embodiments different channel pair information is averaged to obtain a single real and imaginary matrix method 500 continues with tasks 214 through 218 which have been discussed in conjunction with method 200 fig2 it is notable that task 216 recites the use of an m by m array in conjunction with method 500 and method 600 described later in this description in some alternative embodiments the array of hydrophone pair correlation products can be an m by n array in some further embodiments the array can have any geometry for which there is more than one pair of receivers that provides.