Patent ID: 7355545

Claim:
A method for ascertaining the position of a moving object behind a wall, comprising the steps of: positioning at least two through-the-wall CW multi-tone radars at different known positions with respect to the wall such that radar beams cross and penetrate the area behind the wall; determining range to the moving object from each of the radars using the multi-tone returns from the moving object and a background subtraction technique involving detection of changes in range due to a moving object to establish the locus of ranges within the beam of each radar, thus to determine range in terms of a range swath, the range-determining step including the step of comparing the range results at one frequency in terms of a waveform with predicted range results from another frequency in terms of a waveform to determine the most accurate range, the range-determining step including the steps of generating a set of templates for a set of range swaths and matching returns from the multi-tone radars with the templates to determine by the closest match the corresponding range swath; and, ascertaining the location of the overlap of the swaths to obtain the position of the moving object by triangulation without using phase measuring techniques.