EGNOS V3 Legacy Service – Preliminary Performances

Abstract

EGNOS is the European Satellite Based Augmentation System (SBAS) augmenting the GPS and GALILEO constellation by improving the accuracy of their navigation service and monitoring their integrity over Europe. EGNOS V3 (or EV3 in short) is the 2 nd generation of EGNOS currently developed by the industry consortium led by Airbus Defence and Space, under a working contract with the European Space Agency on behalf of the European Commission. EV3 will ensure seamless continuation of the current EGNOS V2 Single Frequency (SF) (“legacy”) service broadcast on L1 frequency. For EV3.1, the 1st release of EV3, it is intended to process Galileo ranging data to improve the ionosphere monitoring, being this mode called the SF “Enhanced” service. In a 2nd implementation step, release EV3.2, it will also augment GPS and Galileo constellations in the so-called Dual Frequency Multi-Constellation (DFMC) service mode to be broadcast in the L5 frequency. This publication presents initial results of the EV3 SF “Legacy” and Enhanced” services under Fault-Free conditions i.e. in the absence of specific GNSS SIS threat cases or system internal failures. The results are produced using a prototype SW of the Central Processing Facility (CPF) called CPF Algorithmic Models (CAM) played on the Service Performance Validation Platform (SPV-P) using representative synthetic and real data scenarios (using EV2 RIMS data). Notwithstanding that CPF-CAM have not reached their CDR level yet, their level of maturity is considered sufficient to provide a preliminary view of the expected performances of the EV3 legacy and enhanced SF services. In parallel it will be provided an overview of the main features of the EV3 CPF-SF algorithms. It is recalled that EV3 CPF contains major evolutions, such as the provision of MT28 instead of MT27 used in current operational EV2, or the implementation of a Bayesian filtering technique for the ionosphere monitoring.