The Dual-frequency Post-correlation Difference Feature for Detection of Multipath and non-Line-of-Sight Errors in Satellite Navigation

Global Navigation Satellite Systems provide users with positioning in outdoor environments, however their performance in urban areas is decreased through errors caused by the reception of signals that are reflected on buildings (multipath and non-line-of-sight errors). To detect these errors, we simulated their influence on the correlator output on two carrier frequencies. Based upon the simulations, a feature using the difference between an ideal correlator output and the received correlator output was developed. This article presents the new Dual-frequency Post-correlation Difference feature and compares its performance with two methods from the bibliography. This new feature outperforms the Code-Minus-Carrier and the signal-to-noise ratio difference features in multipath and non-line-of-sight detection. Furthermore it can distinguish between multipath and non-line-of-sight reception. As a consequence, the method can be used to exclude satellites whose signals are affected by reflections, to provide a more accurate navigation solution.