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Multipath Estimation in Multicorrelator GNSS Receivers using the Maximum Likelihood Principle

Delgado, N. ; Nunes, F.

IEEE Transactions on Aerospace and Electronic Systems Vol. 48, Nº 4, pp. 3222 - 3233, October, 2012.

ISSN (print): 0018-9251
ISSN (online):

Journal Impact Factor: 1,024 (in 2008)

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Abstract
This paper proposes a multipath mitigation technique for
multicorrelator Global Navigation Satellite System (GNSS)
receivers that estimates the line-of-sight (LOS) and the multipath signal parameters in a computationally efficient manner. The maximum likelihood (ML) principle is applied leading to a nonlinear optimization problem. A closed-form solution of the nonlinear estimation problem is proposed where the estimation of the LOS delay is performed using a grid search approach.
Lack of convergence, initialization, and computational complexity problems are avoided and a small computational burden is achieved. A low-complexity complementary method based on interpolation is proposed in order to increase the resolution of the
estimated delay with respect to the limit set by the correlators’
spacing. Theoretical performance and limits are determined considering that the delay is estimated through a grid search approach and the observations are obtained in the presence of nonwhite Gaussian noise due to the correlation between samples.