Bayesian Dll For Multipath Mitigation In Navigation Systems Using Particle Filters

In direct-sequence spread-spectrum (DS-SS) navigation based systems, multipath can degrade seriously synchronization performance causing time delay and code phase estimates, to deviate from the actual value. This bias depends on the relative amplitudes and delays of multipath replicas with respect to the direct signal. The error in the estimated position due to multipath, when using a standard Delay Lock Loop, can be on the order of several tens of meters, which is a critical aspect in high-precision applications. This works presents a Sequential Monte Carlo based algorithm which tries to iteratively estimate complex amplitudes and delays of the direct signal and multipath replicas by characterizing the posterior probability density function of these parameters relying on particle filter theory. Simulations are presented for navigation systems, which are particular applications of DS-SS systems.