Variable suppression of multipath signal effects

Details Variable suppression of multipath signal effects Variable suppression of multipath signal effects

1996-05-20

1999-10-05

Bocure, Tesfaldet

Pulse or digital communications

Receivers

Interference or noise reduction

375200, H03D 104, H04K 100

Patent

active

059636017

ABSTRACT:
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..sub.chip. Two or three consecutive bit values b.sub.n-2, b.sub.n-1 and b.sub.n 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 I.sub.n ={t'.vertline.t.sub.n-1 +.DELTA.<t'.ltoreq.t.sub.n +.DELTA.}, where .DELTA. is a selected time value satisfying 0.ltoreq..DELTA.<.DELTA..tau..sub.chip, to first and second autocorrelation functions AC#(.tau.;E) and AC#(.tau.;L) with respective selected first and second time shifts .tau.=t.sub.E and .tau.=t.sub.L (>t.sub.E). If the test condition is not satisfied, a second weighting function w1 (t) is used to compute the contribution of the time interval I.sub.n to AC#(.tau.;E) and AC#(.tau.;L). An autocorrelation difference function .DELTA.AC#(.tau.)=AC#(.tau.;E)-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).

REFERENCES:
patent: 4007330 (1977-02-01), Winters
patent: 4168529 (1979-09-01), Tomlinson
patent: 4203070 (1980-05-01), Bowles et al.
patent: 4203071 (1980-05-01), Bowles et al.
patent: 4550414 (1985-10-01), Guignon et al.
patent: 4608569 (1986-08-01), Dickey et al.
patent: 4660164 (1987-04-01), Liebowitz
patent: 4829543 (1989-05-01), Borth et al.
patent: 4862478 (1989-08-01), McIntosh
patent: 5091918 (1992-02-01), Wales
patent: 5101416 (1992-03-01), Fenton et al.
patent: 5164959 (1992-11-01), Cai et al.
patent: 5282228 (1994-01-01), Scott et al.
patent: 5347536 (1994-09-01), Meehan
patent: 5390207 (1995-02-01), Fenton et al.
patent: 5402450 (1995-03-01), Lennen
patent: 5414729 (1995-05-01), Fenton et al.
patent: 5444451 (1995-08-01), Johnson et al.
patent: 5481503 (1996-01-01), Kuhn et al.
patent: 5488662 (1996-01-01), Fox et al.
patent: 5493588 (1996-02-01), Lennen
patent: 5495499 (1996-02-01), Fenton et al.
R.E. Ziemer & R.L. Peterson, Digital Communications and Spread Spectrum Systems, MacMillan Publ. Co., New York, 1985, pp. 419-447.
Alfred Leick, GPS Satellite Surveying, John Wiley & Sons, New York, 2cd Edition, 1995, and Ziemer and Peterson, op.cit.
W.M. Bowles, "Correlation Tracking", Charles Stark Draper Laboratory, May 1980.

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