In the attempt of improving the achievable performance and of extending the application domain of the legacy Receiver Autonomous Integrity Monitoring (RAIM) concept, a technique extensively used in aviation to determine the integrity of GNSS position solutions, the EU-US Cooperation on Satellite Navigation Working Group C (WG-C) has developed a proposal for a RAIM evolution called Advanced RAIM (ARAIM). One of the first aims of the ARAIM concept is to enable the use of multiple GNSS constellations (and in particular the combination of GPS and Galileo) for both worldwide air navigation, that supports en-route and terminal-area flight, and lateral and vertical guidance during airport approach operations. In this context, the DARP project, carried out by a consortium led by Deimos Space SLU and co-funded by the EC/GSA, is developing a GNSS receiver prototype that integrates the ARAIM algorithm. The main objectives are to provide an ARAIM proof-of-concept based on the algorithm version proposed by the WG-C in the Algorithm Description Document (ADD) 3.1 , and to perform optimizations and improvements of this algorithm. The prototype is designed to be flexible enough to allow for changes in its configuration and internal components according to the evolution of the ARAIM definition and the project progress, providing in such a way valuable information for the consolidation of WG-C baseline ARAIM. This paper shows an overview of the current status of the project. The main architecture of the receiver and the ARAIM algorithm is shown. Then a summary of the test campaign and the instruments used for the simulation campaign is also described. Taking into account the current level of maturity of the ARAIM standards, the test campaign will focus mainly on validation of Horizontal ARAIM (H-ARAIM) mode concept within the real signal experimental campaign. In addition, the Vertical ARAIM (V-ARAIM) mode will be included in the test campaign based on simulated scenarios, with an overall lower depth of details.