Adaptive Tracking Techniques in Non-Stationary Environments

The continuously changing environments have been the main challenge for classical GNSS receiver implementations, as they can have a great impact on signal tracking performance and positioning. For this reason techniques capable of mitigating the impact of time-varying phenomena by adapting to changing conditions, thus improving performance are of great interest. This study reports the benefits of using adaptive techniques for standalone GNSS receivers in three different scenarios. The first scenario compares an adaptive Kalman filter against a classical DLL/PLL architecture in interference environments with user dynamics. The second scenario uses a multipath propagation channel to test alternative carrier tracking architectures which provide better results in terms of robustness. The third scenario uses the same multipath propagation channel to test the adaptive switching technique, 2-Step, in order to evaluate its capacity of guaranteeing and maintaining unambiguous tracking for BOC-type modulations. In order to assess the performance of these techniques a semi-analytical platform has been used. The results presented here show the benefits and trade-offs of different techniques taking into account different propagation channels and scenarios