An ARAIM Experimental Test User Receiver. Final Review of Project DARP

Abstract

RAIM capable receivers cover the necessity of having a reliable navigation instrument for aviation applications in areas where the receiver is not supported by SBAS. Given the limitations of GPS L1 RAIM and taking advantage of the new GNSS systems in terms of constellations, frequencies and signals, RAIM concept is evolving into the Advanced RAIM (ARAIM) that intends to cover some operational scenarios that legacy RAIM does not cover (as for example the vertical guided approach LPV-200). This was detailed in Working-Group C (2016). There are still some of main ARAIM concept features that are not yet closed. Because of that, it is an asset to have a prototype test user receiver that can be easily reconfigurable to evaluate these new concepts that are still under discussion. That is the aim of project DARP. This was a project leaded by Deimos Space and funded by EUSPA with the objective of designing, developing, and integrating a prototype of receiver aimed for aviation applications with ARAIM system integrated as it was introduced in Wis, et al (2020). The activities of the project have focused on three important parts: the development of a flexible receiver platform; the analysis, design, integration, and improvement of the receiver ARAIM algorithm; and the design and execution of the validation campaign of the test user receiver. This paper details these three parts. An overview of the receiver design and implementation is performed, focusing on its key features applied to aviation application. The ARAIM algorithm implementation is described, focusing on the changes that were applied with respect to the baseline algorithm. Finally, the validation campaign is explained in more detail, focusing on its design and resources used for the execution of the tests and showing some of its more relevant results of the ARAIM algorithm.