Subspace methods applied to multipath mitigation in a navigation receiver
J. Selva · 1999
In a navigation receiver using DS-CDMA and pseudorange estimation, specular reflections with a delay smaller than one chip may introduce a significant positioning error. Several mitigation techniques have been proposed in the literature, like the narrow correlator and the MEDLL (multipath-estimating delay-lock loop) (van Nee, 1995), which make use of several correlators and a single antenna. A related problem is the direction-of-arrival determination to an antenna array, which can be successfully addressed by using several subspace methods like MUSIC (multiple signal classification) (Schmidt, 1986). The direction-of-arrival methods cannot be applied to multipath mitigation, since they lose performance when the impinging signals are coherent or highly correlated. This article proposes a new technique to mitigate the multipath effect on the code timing estimation using an antenna array of arbitrary geometry, and a subspace method which is not affected by the high correlation of the impinging signals. It also provides a channel estimation.