Opportunities and challenges for multi-constellation, multi-frequency automotive GNSS receivers

In this paper, the implementation of a multi-constellation, multi-frequency automotive GNSS receiver is discussed. The main objective of this paper is threefold. First, to identify, in the context of automotive applications, the most promising GNSS signal combination and analyze its benefits and limitations. Second, to propose a receiver architecture that offers sufficient robustness and flexibility to maintain high-accuracy and high-availability navigation capabilities in challenging automotive signal environments as well as to accommodate the particulars of the legacy, new and modernized signals. Third, to optimize the receiver's implementation so that it meets the automotive requirements in terms of size, cost and power consumption. To this end, several front-end architectures are compared and some key aspects of the baseband hardware implementation discussed. Additionally, robust acquisition and tracking algorithms that respectively account for the availability of a second frequency and for the introduction of advanced modulations are presented. Finally, some insights are provided regarding optimization of the PVT performance in terms of multipath mitigation and ionospheric corrections.