GPS short-delay multipath estimation and mitigation based on least square method

The GPS multipath signal model is presented, which indicates that the coherent DLL outputs in multipath environment are the convolution between the ideal DLL outputs and the channel responses. So the channel responses can be estimated by a least square method using the observed curve of the DLL discriminator. In terms of the estimated multipath channels, two multipath mitigation methods are discussed, which are equalization filtering and multi path subtracting, respectively. It is shown, by computer simulation, that the least square method has a good performance in channels estimation and the multi path errors can be mitigated almost completely by either of the methods. However, the multi path subtracting method has relative small remnant errors than equalization filtering.