Detection and Mitigation of Cross-Correlation Interference in High-Sensitivity GNSS Receivers

This paper presents the architecture of a GPS receiver suitable for indoor operation with extremely weak signals. The receiver works in acquisition-only mode, and combines coherent and long non-coherent correlations in order to achieve low sensitivity. It is confirmed by processing simulated and live GPS signals that this kind of receivers must have the capability to detect and mitigate near-far interference. Novel near-far detection and mitigation techniques are proposed. The new detector is based on the different statistics of the two largest cross-correlation peaks in the presence and in the absence of near-far interference, and it outperforms previously proposed detectors in terms of (mis)detection probability and complexity. The mitigation technique is based on the concepts of successive interference cancellation and subspace projection. It is also novel the fact that, according to the proposed receiver architecture, the near- far mitigation technique is only applied selectively, when the detector has found some interfered signals and the interfering signals have been identified. This reduces the computational complexity without any performance penalty, compared to previously proposed techniques that eliminate the contribution of all potentially (but not necessarily) interfering signals.