Abstract: An all-lag rotating-reference correlator correlates a received spread-spectrum signal with a rotating reference code, and produces in each sampling instance N correlation lags corresponding to the correlation of the received signal with 0, 1, . . . , N?1 lags (or delays) of the rotating reference code, wherein N is the length of the rotating reference code. The rotating reference code is time-variant and is generated by a rotation of a basic reference code. The received signal, possibly embedded in noise and interference, consists of periodic replicas of the basic reference code with or without data modulation. The first embodiment of the present invention describes a method and apparatus of an all-lag rotating-reference correlator which is applicable to situations where data modulation is not present in the received signal.