Multipath Performance Analysis for Future GNSS Signals

Abstract

In order to minimize the influence of multipath signals, several approaches can be taken into account. Among them are the use of special multipath limiting antennas, post processing techniques to reduce carrier multipath (e.g. multi-antenna spatial processing) or carrier smoothing to reduce code multipath. However, the most important multipath mitigation approaches are receiverinternal correlation techniques. This paper provides a survey of current receiver-internal correlation techniques that are able to minimize multipath. The techniques discussed in this paper are the Narrow Correlator, Double Delta Correlation techniques, the Early/Late Slope Technique (ELS) and the 1st derivative correlator. As a first step, all these correlation techniques are briefly introduced with respect to their basic functionality and implementation. In a second step, the performance of these multipath mitigation concepts is illustrated in the form of multipath error envelopes. Assuming a dedicated multipath scenario with one multipath component and a constant signal attenuation factor, these diagrams allow an intuitive comparison of different multipath mitigation techniques. For all correlation techniques introduced above, the multipath performance analysis is performed for various current and future GNSS signals. For this purpose, different signal scenarios are defined which also consider Galileo frequency bands and services. Another focus will be placed on the combination of two signals to set up a ionosphere-free linear combination. The multipath performance for such signal combinations is also a topic of this paper.