A method and apparatus for detecting and tracking a coded signal within a noisy background environment, wherein the signal is correlated over subintervals of time both in-phase and in quadrature, stored indices which represent all possible paths of the signal phase are retrieved, in-phase and quadrature...http://www.google.com/patents/US6683923?utm_source=gb-gplus-sharePatent US6683923 - Method and apparatus for detecting and tracking coded signals in a noisy background environment
