| 摘要 |
Method and apparatus for formation of an autocorrelation difference function of an incoming digital signal, with bit transition interval length DELTA tau chip, that reduces the effects of presence of a multipath signal in an incoming composite signal. First and second autocorrelation functions AC( tau ;E;qE) and AC( tau ;L;qL) are formed with respective first and second selected time shift values tau =tE and tau =tL, which replicate an estimate of an autocorrelation function AC( tau ;P;qP) at an intermediate time shift value tau =tP that satisfies tE<tP<tL with tL-tE<2 DELTA tau chip, and which depend upon one or more parameters qE and qL, respectively. Independently chosen, non-uniform weighting functions w1(t;qE) and w2(t;qL) are used for formation of the respective autocorrelation functions AC( tau ;E;qE) and AC( tau ;L;qL) that depend upon one or more parameters qE and qL. Reduction of non-multipath and/or noise effects is achieved by particular choices of weighting functions. The correlator spacing tL-tE may be narrow (e.g., DELTA tL-E</=0.3 DELTA tau chip) or may be any larger value, up to 2 DELTA tau chip, with appropriate choice of the weighting functions w1 and w2.
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