Return Link Service Provider (RLSP) Acknowledgement Service to Confirm the Detection and Localization of the SAR Galileo Alerts

Abstract

The French Space Agency, CNES, has contributed to the international Cospas/Sarsat program since its creation in 1982. This program is a cooperation of 43 states and agencies committed to detecting and locating radio beacons activated by persons, aircraft or vessels in distress. Within this consortium, the return link service provider, RLSP, will be the facility responsible for the establishment of the return link messages and their coordination with the Galileo system, interfacing on one side with the Cospas/Sarcat system and on the other side with the Galileo Ground Mission Segment (GMS). The first version of the RLSP will enable the return link service provision including the acknowledgement service separated into two types:

• Type1—system acknowledgement (Galileo sends message automatically when the alert has been received and located),

• Type 2—rescue coordination centres (RCC) acknowledgement (RLSP transmits the message after authorization from the responsible RCC).

Through the acknowledgement service provision, the RLSP will play a very important role in the Cospas/Sarsat network, because for the first time ever, it will be possible to send feedback messages to the beacons that sent a distress, thus completing the cycle with the beacons. Considering these functionalities and interfaces to put in place with Galileo and Cospas/Sarsat networks, the European Commission entrusted the CNES in order to manage the development of the whole system and also to operate the RLSP with high levels of objectives. After a brief recall of the RLSP functions and Cospas/Sarsat system, this paper will present the numerous technologies and methods put in place to guarantee the performances and the high availability of the system (99.95%) in order to ensure operations on a 7 d/24 h basis. The infrastructure and COTS used or developed to design the RLSP functionalities will be described. Design concepts such as redundancy, scalability, virtualization, real time/non-real time, the database and the Web server will be detailed. The paper will highlight the integration of all these components and their interfaces with external entities. The GMS communicates through a ciphered network, the Cospas/Sarsat network via a VPN, and the rescue coordination centres using the Internet. More than 250 RCC across the world will connect to the RLSP website to acknowledge distress beacons. By consequence, the architecture is a key to the success of this project. A security tradeoff involving national and international actors was made between the architecture and security measures so that the RLSP can be connected to both a closed secured environment such as Galileo, and also to the outside world via the Internet. The main outcomes of this tradeoff will be exposed in article and presentation. This paper will demonstrate how the CNES concepts of operations, with the RLSP, will address the European Commission’s high-level objectives mentioned here above which makes the RLSP state-of-the-art in modern technology. Finally, the paper will conclude with some important lessons learned from the accreditation, integration and qualification phases and the first months in operations of this system.