The world’s global navigation satellite systems (GNSS) such as the United States' global positioning system (GPS), Russia's global navigation satellite system (GLONASS), the European Union's Galileo, and China's BeiDou navigation satellite system-3 (BDS-3) are based on medium earth orbit (MEO) satellites. More recently, regional navigation satellite systems (RNSS), including China's BeiDou navigation satellite system-2 (BDS- 2), India's navigation with Indian constellation (NavIC), and Japan's quasi-zenith satellite system (QZSS), have been developed and are partially operational. These systems consist primarily of geostationary earth orbit (GEO) and inclined geosynchronous orbit (IGSO) satellites. While GEO and IGSO satellites provide continuous visibility over specific countries or regions, they generally have lower orbit determination accuracy than MEO satellites. This is particularly true in the radial direction (from the center of the Earth to the satellite), where position and satellite clock estimation uncertainties can be greater. To address these limitations, most systems employ a variety of complementary methods. For example, BDS-2 uses an inter-satellite link (ISL), and NavIC uses a code division multiple access (CDMA) based ranging system to independently estimate satellite clock. This paper proposes a system that compares the ground system reference clock with the satellite clock. This study is expected to contribute to the improvement of RNSS performance by providing a technical solution for improving satellite clock accuracy.
,br> Keywords: RNSS, TSP, GEO, IGSO

Configuration of Time Synchronization Payload (TSP) System to Complement the Precise Orbit Determination Accuracy of GEO and IGSO Satellites in RNSS

Miri Shin, DeokWon Lim*

The world’s global navigation satellite systems (GNSS) such as the United States' global positioning system (GPS), Russia's global navigation satellite system (GLONASS), the European Union's Galileo, and China's BeiDou navigation satellite system-3 (BDS-3) are based on medium earth orbit (MEO) satellites. More recently, regional navigation satellite systems (RNSS), including China's BeiDou navigation satellite system-2 (BDS- 2), India's navigation with Indian constellation (NavIC), and Japan's quasi-zenith satellite system (QZSS), have been developed and are partially operational. These systems consist primarily of geostationary earth orbit (GEO) and inclined geosynchronous orbit (IGSO) satellites. While GEO and IGSO satellites provide continuous visibility over specific countries or regions, they generally have lower orbit determination accuracy than MEO satellites. This is particularly true in the radial direction (from the center of the Earth to the satellite), where position and satellite clock estimation uncertainties can be greater. To address these limitations, most systems employ a variety of complementary methods. For example, BDS-2 uses an inter-satellite link (ISL), and NavIC uses a code division multiple access (CDMA) based ranging system to independently estimate satellite clock. This paper proposes a system that compares the ground system reference clock with the satellite clock. This study is expected to contribute to the improvement of RNSS performance by providing a technical solution for improving satellite clock accuracy.
,br> Keywords: RNSS, TSP, GEO, IGSO

Speaker Miri Shin 한국항공우주연구원