Japanese GPS system/Quasi Zenith Satellite System

An overview of Japanese GPS system/Quasi Zenith Satellite (QZS) System.

1. JAPANESE GPS SYSTEM -Vinesh Ch. Hanumantharayappa

2. September 1998: Joint Statement by the Government of the United States of America and the Government of Japan on Cooperation in the Use of the Global Positioning System. At the Meeting in Oct. 2002, the two governments agreed to set up a Technical Working Group (TWG) to coordinate technical issues between the QZSS and the GPS. To date, the following have been agreed to at the TWG. Compatibility : the two systems shall be operated without causing any harmful radio wave interference. Interoperability : both systems must be able to receive each others positioning signals by the same antenna and receiving circuit JAPANESE GPS SYSTEM Background of the QZSS Development

3. Quasi-Zenith Satellite System JAPANESE GPS SYSTEM First launch : September 2010 Type : Civilian Status : In development Precision : 0.01-1 meters Total satellites : 4 Satellites in orbit : 1 “MICHIBIKI” QZSS uses three satellites, each 120° apart, in highly inclined, slightly elliptical, geosynchronous orbits. Because of this inclination, they are not geostationary; they do not remain in the same place in the sky. Instead, their ground traces are asymmetrical figure patterns (analemmas), designed to ensure that one is almost directly overhead over Japan at all times.

4. JAPANESE GPS SYSTEM SATELLITE AXES

5. JAPANESE GPS SYSTEM SPACE SEGMENT PARAMETER VALUES NUMBER OF SATELLITES 3 NUMBER OF ORBITS 3 INCLINATION 43 ECCENTRICITY 0.075 MAJOR SEMI AXIS 42164 KM ORBITAL PERIOD 1 SIDERAL DAY PERIGEE DISTANCE 39002 KM APOGEE DISTANCE 45326 KM

6. MCS (Master Control Station) : It determines the precise orbits of QZSS and generates the navigation message for uplink. It will satisfy high availability requirements using a hot-redundant system MS (Monitoring Station ): The GPS signals processed by MS are sent to the MCS, which are used to predict the positions and systems times of the QZSS and GNSS orbits. Based on the results of orbit and time estimates and predictions, navigation messages are generated and sent to the TCS (Tracking and Control Stations) TCS (Tracking and Control Station ): The TCS operations for satellite bus and TT&C (Telemetry Tracking and Command) ground stations control are collocated with MSC. On-board the QZS, a signal with the navigation message superimposed is generated and transmitted to Earth via the L-band transmission antenna and the L1-SAIF transmission antenna JAPANESE GPS SYSTEM GROUND SEGMENT

7. JAPANESE GPS SYSTEM GROUND SEGMENT OVERVIEW