Resilient High Precision Positioning using RTK and Distributed GNSS Antenna Subarrays

The emergence of applications such as autonomous vehicles and UAVs (Unmanned Aerial Vehicles) has lately brought high precision positioning into the focus of the GNSS (Global Navigation Satellite System) community. Simultaneously, such autonomous applications fall under the category of SoL (Safety of Life), applications and therefore require strict protection levels, high integrity, and resilience against GNSS interference. Protection and toughening of GNSS receivers against jamming and spoofing has been a heavily studied subject in the last decade. Literature has proven spatial signal processing algorithms combined with compact antenna arrays to show effectiveness in providing the required resilience. However, due to the large footprint of these arrays, the distribution of smaller subarrays has been considered more aesthetic by the industry and customers alike. Such distributed systems can be installed more discretely and in various synthetic parts of a vehicle. This paper studies such a distributed antenna subarray system in a series of real-world measurements under the use of carrier-phase based RTK (Real Time Kinematics) positioning. The goal of the paper is to meet the requirements of high precision and resilient positioning. A demonstration of sustained high precision positioning under jamming conditions is presented using spatial signal processing algorithms. A statistical analysis is carried out to compare single antenna processing approach against a multi-antenna spatial signal processing one. Assessment of a state-of-the-art carrier-phase compensation algorithm for spatial interference mitigation filter is made to study its benefits for RTK-based positioning using multi-antenna setups.