| Popis: |
Multipath is the main source of error in satellite positioning. Although various multipath reduction and delay estimation techniques have been developed, short-delay multipath is still a problem area particularly for high precision applications, indoor use and under dense urban environments. The number of close-in secondary paths is not only high in indoor and urban areas but also dynamic in nature because of presence of closely-spaced stationary and moving reflecting objects such as people, plants, buildings and vehicles, around the receiving antenna. Thus a delay estimation approach with good accuracy, less computational cost and capability of handling both static and dynamic multipaths environments is always desired. One such concept has been proposed based on the exploitation of properties of non-linear Teager-Kaiser (TK) energy operator for estimating and tracking the true delay under multipath environment. This operator is applied to the cross-correlation function between the received signal and the reference spreading code replica generated at the receiver to estimate the closely-spaced delays. So far, various implementation approaches have been developed for TK method giving good results based on simulations. In this paper, the performance of TK method is analyzed experimentally by collecting & processing GPS L1 data and comparing the results with the standard DLL discriminator. The results show that TK method is capable of distinguishing sub-chip multipath delays accurately with a lower computational cost. |
