Low Computational-Complexity vector tracking for Low-Cost GNSS receivers

Abstract

Estimating the position, velocity, and time of GNSS receivers is based on tracking loops and extracting navigation satellite information. There are two methods for navigation satellites signal tracking: Scalar Tracking Loop (STL) and Vector Tracking Loop (VTL). The inexpensive GNSS receivers usually use STL approach, but VTL approach has advantages such as weak signal tracking, better capability against signal interference, faster tracking after temporary signal outages. Hence, using this method for tracking can improve the performance of GNSS receiver. The main drawback of the VTL method is its high computational volume. In this paper, three techniques have been proposed to reduce the computational load of this tracking method that enables the implementation of the VTL method on inexpensive receivers. The results with real data and simulations show that if these three techniques are used simultaneously, the computational load is reduced by more than 90% and on the one hand; the performance of the tracking loops shows no significant reduction compared to the standard VTL. Therefore, the simultaneous use of these three techniques to implement the VTL method can be very effective on low-cost and low-dynamic receivers. Two techniques of the three proposed techniques can also be used to implement the VTL on all types of GNSS receivers.