A method, apparatus, computer program, chip set, or data structure for correlating a digital signal and a correlation code

摘要

In a correlator, the assumed or measured movement of a GNSS (GPS or Galileo), LTE or CDMA receiver is used to compensate a reference signal for Doppler shifts in the received signal using one or more phasors (phase shifts) dependent upon the movement. This allows longer correlation (integration) times using a long reference consisting of repeated reference signals, and reduction of multipath effects. Open loop control is possible, or closed loop control, in which the correlation is used to maintain carrier phase and code alignment. Early, late and prompt versions of the compensated reference code can each be correlated with the received signal. Compensated reference signals may be stored, indexed by the motion, and re-used until the velocity of the receiver changes significantly.