Real Time Results of Vector Delay Lock Loop in a Light Urban Scenario

Abstract

The need of a robust navigation solution increased during the last decade. As an example, for autonomous driving it is essential to have a stable satellite signal tracking even in difficult environments such as urban canyons. The paper describes a real-time vector delay lock loop (VDLL) approach implemented directly on the GNSS receiver hardware to achieve a deep integration in the signal processing. This approach uses the code correlation values fetched directly from the receiver hardware to provide an estimated position, velocity and time (PVT) solution using an extended Kalman filter (EKF). The solution is then used to calculate new steering code values for all channels at the same time, which are sent back to the hardware to steer the code numerically controlled oscillators (NCOs). The approach is tested in a real-world light urban scenario, where different signal degradations occur including multipath, signal shadowing or reflections. The VDLL real-time implementation is analyzed and compared to a reference system. A detailed description of the scenario and the used GNSS receiver hardware is shown.