MAI-Mitigation and Near-Far-Resistance Architectures for GNSS Receivers

Abstract

Multipath, MAI (Multiple Access Interference) and near-far effects are the three main influences on the performance of CDMA-based communication and navigation systems. A great deal of research has been conducted to develop advanced signal processing algorithms and novel receiver structures useful for mitigation of these effects in mobile land wireless communication systems, such as UMTS. Although the multipath effects on PRN code ranging in GNSS have been investigated for about two decades, the MAI and near-far effects have only been discussed in pseudolite applications. In this paper, the impairments of the satellite-mobile receiver channel with multipath-selective fading, and shadowing/attenuation effects by objects such as trees/forests and buildings, are theoretically analysed, under a more general and practical definition of the "near-far" effect. The MAI-mitigation and near-far resistant receiver structures for Galileo/GNSS applications are presented. The principles of such receiver structures and their applications in GNSS are discussed. Both theoretical analyses and computer simulations are presented and show the applicability of the proposed receiver structures.