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QZSS(Quasi-Zenith Satellite System)

Peter Špilovský. QZSS(Quasi-Zenith Satellite System). What is QZSS. Is a Japanese Regional Satellite system Was authorized by the Japanese government in 2002

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QZSS(Quasi-Zenith Satellite System)

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  1. Peter Špilovský QZSS(Quasi-Zenith Satellite System)

  2. What is QZSS • Is a Japanese Regional Satellite system • Was authorized by the Japanese government in 2002 • The navigation system objective is to broadcast GPS-interoperable and augmentation signals as well as original Japanese signals from a three spacecraft constellation in inclined, elliptical geosynchronous orbits • With this system concept, users in and around Japan and Oceania/Australia can use seamless positioning, navigation, and timing services, even in urban canyons and mountainous areas • QZSS applications are: mobile mapping, IT aided precise farming, IT aided construction, fleet management, marine and transportation applications, among others • The space segment consists of three satellites, that are placed in periodic Highly Elliptical Orbit (HEO)

  3. A bit of history • At the beginning the system was developed by the Advanced Space Business Corporation (ASBC) team, including Mitsubishi Electric Corp., Hitachi Ltd., and GNSS Technologies Inc. • In 2007 the Advanced Space Business Corporation collapsed • Then the work was taken over by JAXA together with Satellite Positioning Research and Application Center (SPAC), established in February 2007 and approved by the Ministers associated with QZSS research and development

  4. The first satellite called Michibiki (guide or show the way) was launched on 11 September 2010 • Fully operational status is expected by 2013 • The goal of QZSS is to provide a means of improved and secure navigational references to be used nationwide for many applications in all facets of modern life

  5. It’s function • Compared to standalone GPS, the combined system GPS + QZSS will improve positioning performance via correction data provided through sub meter-class enhancement signals L1-SAIF and LEX. It will also improve reliability by means of failure monitoring and system health data notifications. The specification performances are: • The Signal-in-Space (SIS) User Range Error: less than 1.6 m (95%), including time and coordination offset error. • Single Frequency User positioning accuracy (positioning accuracy combined GPS L1_C/A and QZSS L1_C/A): 21.9 m (95%). • Dual Frequency User (L1-L2) positioning accuracy: 7.5 m (95%). • L1-SAIF signal users (using WDGPS correction data) positioning accuracy: 1m sigma rms) except in cases of large multipath error and large ionosphericdisturbance • For Single Frequency users the expected performances are three times better than the specified ones in nominal conditions, i.e. 7.5 m (95%)

  6. QZSS map

  7. Space Segment

  8. QZSS is designed so that at least one satellite out of three satellites exists near zenith over Japan • Given its orbit, each satellite appears almost overhead most of the time (i.e., more than 12 hours a day with an elevation above 70°) • The design life of the quasi-zenith satellites is of 10 years

  9. RAAN- Right Ascension of Ascending Node • Is an angle, measured at the center of the earth, from the vernal equinox to the ascending node. It is a number in the range 0 to 360 degrees • We can also use Aries (this is also the same location as the vernal equinox). So, the angle, from the center of the Earth, between Aries and the ascending node is called the RAAN

  10. Ground Segment • MCS (Master Control Station): The MCS acts as a focal point. 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): About 10 monitoring stations will be situated in Japan and in Asian/Oceania regions to receive QZS and GPS signals for precise estimation of QZS orbit. 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)

  11. 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. The main TT&C ground station will be located in the Okinawa prefecture, whereas the TCS will be at JAXA's Tsukuba Space Center throughout the first stage of QZSS. The GEO satellite operation system can be applied with minimum modification for the QZSS since the QZSS constellation provides continuous visibility. 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

  12. Signal Specification

  13. Frequency Plan

  14. Thank you for your attention

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