Tracking improvement for vehicular applications due to use of a Vector Delay Lock Loop

In this paper a Kalman Filter is introduced in the GPS-L1 signal tracking loop to improve its robustness in adverse environments. The proposed algorithm uses two different approaches with respect to the carrier and to the code: the carrier tracking is performed by a single three-state Kalman Filter for each channel, in addition to the traditional PLL Costas loop. A vector loop is used, instead, to track the code by an Extended Kalman Filter (EKF) to process the information provided by all the receiver channels. First, the mathematical model of the system is described. After the Kalman Filter parameter tuning, three different tests are performed tracking both simulated and real data by a Software-Defined Radio GNSS receiver implemented in Matlab© (based on an Open Source code provided by 1 In the end an exhaustive analysis of the results is made by comparing them to the performances of a traditional tracking loop.