Quasi-Zenith Satellite System
JPY 170 billion | |
Website | qzss |
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The Quasi-Zenith Satellite System (QZSS), also known as Michibiki (みちびき), is a four-satellite regional
History
In 2002, the Japanese government authorized the development of QZSS, as a three-satellite regional
The first satellite "Michibiki" was launched on 11 September 2010.[9] Full operational status was expected by 2013.[10][11] In March 2013, Japan's Cabinet Office announced the expansion of QZSS from three satellites to four. The US$526 million contract with Mitsubishi Electric for the construction of three satellites was scheduled for launch before the end of 2017.[12] The third satellite was launched into orbit on 19 August 2017,[13] and the fourth was launched on 10 October 2017.[14] The basic four-satellite system was announced as operational on 1 November 2018.[4]
Orbit
QZSS uses one
The nominal orbital elements are:
Epoch | 26 December 2009, 12:00 UTC |
Semimajor axis (a) |
42,164 km (26,199 mi) |
Eccentricity (e) |
0.075 ± 0.015 |
Inclination (i) |
43° ± 4° |
Right ascension of the ascending node (Ω) |
195° (initial) |
Argument of perigee (ω) |
270° ± 2° |
Mean anomaly (M0) | 305° (initial) |
Central longitude of ground trace | 135° E ± 5° |
Planned seven satellites constellation consists of four Quasi-Zenith Orbit (QZO) satellites, two geostationary (GEO) satellites, and one quasi-geostationary (slight incline and eccentricity) orbit satellite.[16]
Satellites
Name | Launch date | Status | Notes |
---|---|---|---|
QZS-1 (Michibiki-1) | 11 September 2010 | Replaced by QZS-1R | Experimental. Lacks MADOCA and PTV signals. Acting as spare since March 2022.[17] Decommissioned on 15 September 2023.[18] |
QZS-2 (Michibiki-2) | 1 June 2017 | Operational | Improved solar panels and increased fuel |
QZS-3 (Michibiki-3) | 19 August 2017 | Operational | Heavier design with additional S-band antenna on geostationary orbit at 127° E[16] |
QZS-4 (Michibiki-4) | 10 October 2017 | Operational | Improved solar panels and increased fuel |
QZS-1R (Michibiki-1R) | 26 October 2021 | Operational | Replacement for QZS-1.[19] |
QZS-5 | JFY2024 | Planned | [20] |
QZS-6 | JFY2025 | Planned | Geostationary at 90.5° E[16][20][21] |
QZS-7 | JFY2025 | Planned | Quasi-geostationary around 190° E[16][20][21] |
QZSS and positioning augmentation
The primary purpose of QZSS is to increase the availability of GPS in Japan's numerous
Signals and services
The QZSS provides the following classes of public service:[22]
- The PNT (Positioning, Navigation and Timing) service complements the signals used by the GPS system, essentially acting as extra satellites. The QZSS satellites sync their clocks with GPS satellites. The service broadcasts at frequency bands L1C/A, L1C, L2C, and L5C, the same as GPS.[23]
- The SLAS (Sub-meter Level Augmentation) service provides a form of GNSS augmentation for GPS interoperable with other GPS-SBAS systems. The principle of operation is similar to that of, e.g. Wide Area Augmentation System. It transmits on L1.[23]
- The CLAS (Centimeter Level Augmentation) service provides high-precision positioning compatible with the higher-precision E6 service of Galileo. The band is referred to as L6 or LEX, for "experimental".[23]
- The MADOCA-PPP (Multi-GNSS Advanced Orbit and Clock Augmentation – Precise Point Positioning) service is a L6 augmentation service independent from CLAS.
- The DC Report (Satellite Report for Disaster and Crisis Management) service broadcasts on L1S and provides information on floods and earthquakes.
The other classes of service are not publicly available:
- The PTV (Positioning Technology Verification) service broadcasts on L5S. The documentation only describes a "null" message type.
- The Q-ANPI (QZSS Safety Confirmation Service) is an authorized short message service.
QZSS timekeeping and remote synchronization
Although the first generation QZSS timekeeping system (TKS) will be based on the Rb clock, the first QZSS satellites will carry a basic prototype of an experimental crystal clock synchronization system. During the first half of the two year in-orbit test phase, preliminary tests will investigate the feasibility of the atomic clock-less technology which might be employed in the second generation QZSS.
The mentioned QZSS TKS technology is a novel satellite timekeeping system which does not require on-board atomic clocks as used by existing navigation satellite systems such as BeiDou, Galileo, Global Positioning System (GPS), GLONASS or NavIC system. This concept is differentiated by the employment of a synchronization framework combined with lightweight steerable on-board clocks which act as transponders re-broadcasting the precise time remotely provided by the time synchronization network located on the ground. This allows the system to operate optimally when satellites are in direct contact with the ground station, making it suitable for a system like the Japanese QZSS. Low satellite mass and low satellite manufacturing and launch cost are significant advantages of this system. An outline of this concept as well as two possible implementations of the time synchronization network for QZSS were studied and published in Remote Synchronization Method for the Quasi-Zenith Satellite System[24] and Remote Synchronization Method for the Quasi-Zenith Satellite System: study of a novel satellite timekeeping system which does not require on-board atomic clocks.[25][non-primary source needed]
See also
- Multi-functional Satellite Augmentation System(MSAS)
- Inclined orbit
- Tundra orbit
References
- ^ "Quasi-Zenith Satellite Orbit (QZO)". Archived from the original on 9 March 2018. Retrieved 10 March 2018.
- ^ "[Movie] Quasi-Zenith Satellite System "QZSS"". Quasi-Zenith Satellite System(QZSS). Archived from the original on 15 July 2017. Retrieved 19 July 2017.
- ^ "Start of QZS-4 Trial Service". Quasi-Zenith Satellite System (QZSS). Archived from the original on 10 August 2018. Retrieved 2 May 2018.
- ^ a b "Japan's QZSS service now officially available". 26 November 2018. Retrieved 11 January 2019.
- ^ "Japan mulls seven-satellite QZSS system as a GPS backup". SpaceNews. 15 May 2017. Retrieved 10 August 2019.
- ^ Kriening, Torsten (23 January 2019). "Japan Prepares for GPS Failure with Quasi-Zenith Satellites". SpaceWatch.Global. Retrieved 10 August 2019.
- ^ Kawahara, Satoshi (8 May 2023). "Japan plans expansion of homegrown GPS network to 11 satellites". Nikkei Asia.
- ^ "Service Status of QZSS" (PDF). 12 December 2008. Archived from the original (PDF) on 25 July 2011. Retrieved 7 May 2009.
- ^ "Launch Result of the First Quasi-Zenith Satellite 'MICHIBIKI' by H-IIA Launch Vehicle No. 18". JAXA. 11 September 2010. Archived from the original on 20 March 2012. Retrieved 12 December 2011.
- ^ "QZSS in 2010". Asian Surveying and Mapping. 7 May 2009. Retrieved 7 May 2009.[dead link]
- ^ "GNSS All Over the World". GPS World Online. 1 November 2007. Archived from the original on 23 August 2011. Retrieved 12 December 2011.
- ^ http://www.spaceflightnow.com/news/n1304/04qzss/ Japan to build fleet of navigation satellites at the Wayback Machine (archived 2013-04-11)
- ^ "Launch Schedule". Archived from the original on 9 August 2018. Retrieved 20 August 2017.
- ^ "Launch Schedule". Spaceflight Now. Archived from the original on 16 August 2018. Retrieved 20 August 2017.
- ^ Interface Specifications for QZSS, version 1.7, JAXA, 14 July 2016, pp. 7–8, archived from the original on 6 April 2013
- ^ a b c d 準天頂衛星の7機体制に向けた開発について (PDF) (in Japanese). Cabinet Office, Government of Japan. 23 January 2019. Retrieved 4 March 2024.
- ^ NAQU 2022059, accessible via "NAQU Message". Quasi-Zenith Satellite System (QZSS).
- ^ "Suspension of QZS-1 all operations". Quasi-Zenith Satellite System. 15 September 2023. Retrieved 16 September 2023.
- ^ "宇宙基本計画工程表 (令和2年6月29日)" [Space Plan Schedule (2020 June 29)] (PDF) (in Japanese). Cabinet Office (Japan). 29 June 2020. p. 54. Retrieved 6 December 2020.
- ^ a b c 宇宙基本計画⼯程表(令和5年度改訂) (PDF) (in Japanese). Cabinet Office, Government of Japan. 22 December 2023. Retrieved 4 March 2024.
- ^ a b Ryan, Dorothy (3 December 2020). "Lincoln Laboratory is designing a payload to integrate on Japanese satellites". MIT. Retrieved 6 December 2020.
The laboratory is working with the Japanese National Space Policy Secretariat and Mitsubishi Electric Company to integrate state-of-the-art sensors on the newest satellites in the QZSS constellation, QZS-6 and QZS-7, which are scheduled for launch in 2023 and 2024, respectively.
- ^ Quasi-Zenith Satellite System Performance Standard PS-QZSS-003 (Mar.17, 2022)
- ^ OCLC 1036065024.
- ^ Fabrizio Tappero (April 2008). "Remote Synchronization Method for the Quasi-Zenith Satellite System" (PhD thesis). Archived from the original on 7 March 2011. Retrieved 10 August 2013.
- ISBN 978-3-639-16004-8.
- Petrovski, Ivan G. QZSS - Japan's New Integrated Communication and Positioning Service for Mobile Users. GPS World Online. 1 June 2003
- Kallender-Umezu, Paul. Japan Seeking 13 Percent Budget Hike for Space Activities. Space.com 7 September 2004
- QZSS / MSAS Status Kogure, Satoshi. Presentation at the 47th Meeting of the Civil Global Positioning System Service Interface Committee (CGSIC) 25 September 2007
External links
- Government Of Japan QZSS site
- JAXA QZSS site(in Japanese)
- JAXA MICHIBIKI data site (in Japanese)
- JAXA MICHIBIKI data site, English subsite
- JAXA Quasi-Zenith Satellite-1 "MICHIBIKI" Archived 22 January 2013 at the Wayback Machine
- JAXA MICHIBIKI Special Site
- ESA Navipedia QZSS article