Variable suppression of multipath signal effects

摘要

Method and apparatus for formation of an autocorrelation difference function of an incoming digital signal that reduces the effects of presence of a multipath signal or of noise in an incoming digital composite signal. An incoming digital composite signal, including direct and multipath signals, is received that has a bit value transition interval of length DELTA tau chip. Two or three consecutive bit values bn-2, bn-1 and bn of the direct (ideal) signal are examined. If a test condition for these bit values is satisfied, a first non-uniform weighting function w1(t) is used to compute the contribution of a time interval In={t'|tn-1+ DELTA tE) If the test condition is not satisfied, a second weighting function w1+E,cir +EE (t) is used to compute the contribution of the time interval In to AC#( tau ;E) and AC#( tau ;L). An autocorrelation difference function DELTA AC#( tau )=AC#( tau ;E) and AC#( tau ;L) is formed in which the effects of noise or of multipath signals is suppressed, relative these effects in a conventionally computed autocorrelation difference function DELTA AC( tau )=AC( tau ;E)-AC( tau ;L).