Patent ID: 6903685

Claim:
A passive system for locating a transmitter, said transmitter producing a transmitter signal of a known frequency and known modulation scheme, said system comprising: at least one antenna array having a first antenna element, a second antenna element, and a third antenna element, said first antenna element being operable for receiving a first received signal from said transmitter, said second antenna element being operable for receiving a second received signal from said transmitter, said third antenna being operable for receiving a third signal from said transmitter; and electronic circuitry for said antenna array to determine a first phase difference and a second phase difference between said first received signal, said second received signal, and said third received signal, said electronic circuitry being operable for utilizing said first phase difference and said second phase difference for determining location information related to a vector oriented in a direction of said transmitter with respect to said at least one antenna array, wherein said electronic circuitry comprises: a spread spectrum receiver with a first receiver channel for processing said first received signal from said first antenna element, a second receiver channel for processing said second received signal from said second antenna element, and a third receiver channel for processing said third received signal from said third antenna element; and a first finger for said first receiver channel, a second finger for said second receiver channel, and a third finger for said third receiver channel, each of said first finger, said second fingers and said third finger being operable for performing a Fast Walsh Transform to determine a winning Walsh symbol based on magnitude and not phase of a Walsh vector.