Wide Area Network (WAN) Connectivity Validation on Installed Sites of Korea Augmentation Satellite System (KASS)

Abstract

The Korean satellite based augmentation system (SBAS) named the Korea augmentation satellite system (KASS) program has been initiated in October 2014. The program work is currently in the system qualification phase. The KASS complies with the SBAS requirements from the International Civil Aviation Organization (ICAO) published in Annex 10. The KASS signal-in-space also complies with the corresponding requirements in the SBAS minimum operational performance standards (MOPS) published by Radio Technical Commission for Aeronautics (RTCA). The KASS system has four ground subsystems and two GEO satellites. The configuration of the KASS ground subsystems comprises of seven KASS reference stations (KRS), two KASS processing stations (KPS), two KASS control stations (KCS) and three KASS uplink stations (KUS). The KRS collects measurement data and broadcast messages from all GPS and geostationary earth orbit (GEO) satellites in view and delivers the data and messages to the KPS. The KPS performs correction processing, safety processing, and SBAS message processing. The KUS generates “GPS-like” signals combined with the SBAS messages from the KPS and transmits them to the GEO satellites. The GEO satellites receive signals from the KUS and transmit GPS compatible signals. The KCS controls and monitors all the KASS subsystems. The KASS system comprises the network segment ensuring all subsystems distributed across Korea wide area network (WAN) and the WAN network monitoring (WNM). The virtual private network (VPN) for WAN were installed in each subsystem sites and one of key parameters for the WAN qualification was verified with data stream generated by tool. This connectivity validation which is to ensure the reliability of the dedicated line and network equipment by measuring the number of delays and losses of packets transmitted from the KASS WAN, which enables the detection of coarse unstable line installations. This paper covers the overall KASS WAN architecture on the installed sites, measurement methods and, the connectivity validation results. The connectivity validation measures delay and loss of the dedicated line and equipment connected between the subsystems at each site. Although the measurements have been observed during the test period, the connectivity validation results satisfied the confidence level to be assigned by system requirements.