Galileo H-ARAIM Characterization and Galileo Integrity Support Message (ISM)

This paper provides an update on two essential aspects related to the future support of Galileo to Advanced Receiver Autonomous Integrity Monitoring (ARAIM) service: performance assessment and Integrity Support Message (ISM) format. The first part of this paper gives a detailed measurement characterization of the Galileo performance parameters relevant for ARAIM users, with particular view on URA and Broadcast Group Delay (BGD) error overbound. This work is one of the important outcomes of the Integrity Failure Mode and Effect Analysis (IFMEA) that has been established for Galileo in the frame of the Galileo Open Service Safety of Life (GoSoL) work plan set up by the European Commission. The work presented in this paper has been conducted by ESA, EUSPA and EC together with industry. These results are an extension of the prior work presented on [13.] and [14.] considering an enlargement of the observation period for Galileo of approximately 24 and 12 months respectively. The additional monitoring period has corroborated the good performance on the SoL relevant parameters and the fulfillment of the target Psat, Pconst and URA as per Galileo SARPs [16.]. The second part of this paper addresses the Galileo ISM format that will be disseminated through the Galileo Signal-in-Space. This paper describes the initial design of the Galileo ISM message type, together with the corresponding processing logic at the user receiver. Additionally, the E1B I/NAV message stream broadcast by Galileo satellites, at a rate of one I/NAV word (128 bits) per 30-seconds sub-frame, can also accommodate ISM from other constellations.