Multipath Mitigation by Voting Channel Impulse Response in Navigation Domain with High-sensitivity GNSS Receivers

High sensitivity GNSS receivers have proven to be of great potential in vast applications, such as location based services, vehicular and pedestrian purposes. When it comes to challenged environments, the signal tracking and navigation solution may encounter many difficulties and get degraded results. Vector tracking receivers that take advantages of mutual information among satellites are usually used, and sometimes can improve performance. However, it generally requires other operations, such as filtering along time, smoothing by using Doppler or even extending coherent integration using data bit wipe-off. In certain scenarios, multipath and cross correlation may still significantly affect the performance, and it is difficult to assess whether or not the bottleneck is due to signal tracking and/or navigation solution. This paper focuses on evaluating the performance of code phase tracking in some challenged environments. No extended coherent integration, no filtering or smoothing is applied. Navigation domain multipath mitigation methods that use maximum likelihood vector tracking architecture and maximum likelihood navigation solution are introduced. Both foliage and downtown data show more robust code phase tracking and more reliable positioning can be achieved by using the algorithm proposed herein.