this fdsmooth ™ frequency domain code multipath mitigation technique for real - time application . firstly , a multipath spectral estimation technique is used to provide multipath frequency spectrum analysis , which was used to bound the frequency domain region for mitigation ; either a multipath model or spectral estimation on the gnss observable data can be accomplished secondly , a code - minus - carrier analysis exposes the major code multipath error and its frequency spectrum , which was the basis for operation ; thirdly , a code multipath correction was formed and applied to mitigate the multipath error in the gnss code measurement . both the multipath mitigated code measurement and the carrier phase measurement can be utilized for the user solution , which improves performance . the technique is well suited for ground - based applications where the multipath fading frequency can be well predicted , as well as , for mobile user applications where this multipath frequency can be estimated using a spectral estimation technique .