First Signal-in-Space for KOREA Augmentation Satellite System (KASS)

Thales Alenia Space is recognized as a world leader in satellite based navigation systems, in particular, as the prime contractor for EGNOS V2. Korea Aerospace Research Institute (KARI) for the government of the Republic of Korea, selected Thales Alenia Space as industry prime contractor for the development of KASS program. In this frame, Thales Alenia Space has designed a new and innovative solution for KASS Uplink Station (KUS). Following KUS deployments, first Signal-in-Space (SiS) transmission through MEASAT-3D on Pseudo Random Noise (PRN) 134 occurred in December 2022. The KUS is composed of two subsystems: the KUS Signal Generation Subsystem (KUS/SGS) developed by Thales Alenia Space to ensure the signal generation and the long loop and the KUS Radio Frequency Subsystem (KUS/RFS) developed by KT&KTSAT that ensures the signal amplification and the interface with the satellite. The heart of the SBAS signal generation is ensured by two functions of the KUS/SGS : the first European Signal Generator used in SBAS uplink station implementing GEO L1 and L5 signal generation according to [1], [2], and [3] and the long loop algorithm which is a dedicated software thread aiming to compute delays and frequency shifts to synchronize to Global Positioning System (GPS) time L1 and L5 messages emission at the phase center of the GEO satellite broadcasting antenna. This paper presents the overall KASS system design related to uplink stations implementation, the design and main features of the KUS/SGS and an overview of the performances obtained during both KUS/SGS factory qualification and on site acceptation including the KUS/RFS and the KASS first geostationary satellite (MEASAT-3D) demonstrating the main performances achievement. Through its flexibility and its high level of performance, the KUS/SGS design is a perfect candidate to address any needs of SBAS uplink station for other SBAS programs.