Patent ID: 6304515
Filing Date: 2001-10-16
Classification: G01S

Abstract:
A method of detecting at least one primary signal in multipath conditions, comprising the steps of:(a) collecting data from at least one input channel,(b) forming at least one function of said data whose output contains information about multipath lags from at least one of said primary signals,(c) evaluating the function output to see if it resembles at least one physically possible arrangement of signal lags thereby indicating the presence of at least one said primary signal;where said physically possible arrangement of signal lags is generated by forming said lags from at least one set of modeled multipath travel times, t.sub.i (m); m=1, 2, . . . N.sub.i.gtoreq.1, with said modeled travel time of path m to said channel i being t.sub.i (m), where at least one of the following equations is used to form said signal lags:for said lags, .tau..sub.ii (m, n), at said channel i,.tau..sub.ii (m,n)=t.sub.i (m)-t.sub.i (n);m.noteq.n,1.ltoreq.m.ltoreq.N.sub.i and 1.ltoreq.n.ltoreq.N.sub.i,for said lags between said channels i and j,.tau..sub.ii (q,1)=.tau..sub.ij (q,n)-.tau..sub.ij (1,n);i.noteq.j,or,.tau..sub.ii (1,q)=-.tau..sub.ij (q,n)+.tau..sub.ij (1,n);i.noteq.j,where,i=1, 2, 3, . . . Rj=1, 2, 3, . . . Rn=1, 2, 3, . . . N.sub.j ; for i<jn=1; for i>jq=2, 3, . . . N.sub.i,where said lag between said channels i and j from said paths k and l is .tau..sub.ij (k, l)=t.sub.i (k)-t.sub.j (l), and the number of said channels is R and at least one channel has more than one path, and, as an option, at least one amplitude of said signal lags is estimated from either deterministically or stochastically modeled multipath amplitudes, a.sub.i (m); m=1, 2, . . . N.sub.i.gtoreq.1, where said amplitude of said path m at said channel i is a.sub.i (m);whereby said data are evaluated for presence of at least one said primary signal on at least one said input channel.