準天頂衛星システム–Jun tenchō eisei shisutemu
Sep 13, 2010 6:00 am
Japan Launches Its First GPS Satellite
By Martyn Williams, IDG News
Japan launched on Saturday the first of a planned series of satellites that promise to improve the accuracy of satellite navigation services in the country.
The «Michibiki» satellite was sent into space atop a Japanese H-IIA rocket from the country’s Tanegashima Space Center at 8:17 pm local time on Saturday (sep12). The satellite later deployed its solar panels to complete a successful launch, the Japan Aerospace Exploration Agency said on Sunday.
Michibiki is the first in a planned series of three satellites that will provide navigation signals focused on the Japanese islands. Key to their mission is a figure-of-eight orbit that will see them make a tight northern swing over Japan and a much broader southern pass over Australia. This «quasi-zenith» orbit gave the project its name: Quasi-Zenith Satellite System (QZSS).
The orbit has been designed so that one of the planned three QZSS satellites is always in the skies above Japan. Because it will be almost directly above the country its signals should be able to reach many city-center streets and country areas that are sometimes out of the range of global positioning satellites because of skyscrapers or mountains.
The satellites will also broadcast a signal correcting any errors in GPS data so that positioning services can be delivered with more accuracy.
The signals are intended to be compatible with those broadcast by existing satellites so should work with current navigation equipment without modification.
Japan’s QZSS system is one of a number of satellite positioning networks planned or under construction by countries eager to reduce their reliance on the U.S.-built and controlled NAVSTAR GPS network.
With satellite navigation playing an increasingly important part in safety systems and commerce, its importance to national economies has risen, thus the wish of some countries to have control over a system of their own.
Launch of satellites for two of the biggest networks, Russia’s GLONASS and the European Union’s Galileo, are already under way. China has plans to turn its regional COMPASS network into a global system and India has also announced plans to build a service.
Martyn Williams covers Japan and general technology breaking news for The IDG News Service. Follow Martyn on Twitter at @martyn_williams. Martyn’s e-mail address is firstname.lastname@example.org
Government plans Japan’s own GPS
The Yomiuri Shimbun
The government plans to launch six or seven satellites over two years from 2014 to establish a Japanese version of the Global Positioning System that would be 10 times more accurate than GPS services currently available in Japan, according to a government source.
They would be of the same type as the so-called quasi-zenith satellite Michibiki (guidance) that was launched in September, or of a geostationary type.
The project is being drafted by the Strategic Headquarters for Space Development headed by Prime Minister Naoto Kan. The government wants to finalize the plan in August.
The project is expected to cost as much as 200 billion yen. Given current fiscal constraints, the government is contemplating adopting the so-called private finance initiative (PFI) formula that utilizes funds, technology and management expertise from the private sector.
The government plans to submit to the next ordinary Diet session a revision bill for the PFI law so that it will cover satellite production projects.
The project to develop Japan’s own GPS is intended to reduce the country’s reliance on the GPS satellite network of the United States.
The U.S. network was originally devised for military purposes. Therefore, there is a possibility that radio wave transmissions even for private use will be obstructed by a third nation in times of emergency, affecting civilian life and economic activities.
The Japan Aerospace Exploration Agency launched Michibiki in September to cover the blind spots not covered by the 30 U.S. navigation satellites that are the foundation of the existing GPS.
If three navigation satellites like Michibiki are put into orbit, at least one would be above Japan for eight hours a day to provide 24-hour coverage. If the Japanese version of the GPS is used together with that of the United States, it will be possible to reduce the margin of error in car navigation and other services from the current 10 meters to less than a meter.
Manufacturing and launching will cost about 35 billion yen per satellite, meaning more than 200 billion yen would be needed to build and launch six satellites.
The life span of a satellite is estimated at 15 years. Taking this into account, the government will pay 13 billion yen a year in usage fees to private businesses after revising the PFI law.
The envisaged development of a more accurate GPS will enable automated operations of agricultural machines at large farms and heavy-duty machinery at construction sites as well as contribute to the safety of railway and aircraft transport operations.
It also may open up new business opportunities in such fields as exploration of natural resources and disaster prevention, observers said.
(Jan. 6, 2011)
Japan’s new satellite provides accuracy down to 3cm
Jan 6, 2011 gps navigation, gps satellites
Currently your GPS navigation system in your vehicle has an accuracy of about 10 meters – good enough to figure out which street you’re on. That’s not enough for Japanese though. They’re just experimenting with the signals from Michibiki satellite which complements the traditional GPS signals. Mitsubishi and the Japan Aerospace Exploration Agency (JAXA) got together and tested their system on a car traveling at 20km/h and got down to 3cm accuracy.
This is still all testing though. They’re need a couple of those satellites just to get 24 hours coverage over just Japan. Currently Michibiki provides only eight hours of coverage.
JAXA and Mitsubishi say the new technology will be useful for good ol car navigation systems but also for advanced construction machines, and also child monitoring systems
«MICHIBIKI» Chosen as Nickname of the first Quasi-Zenith Satellite
Published by Klaus Schmidt on Wed Jan 20, 2010 9:40 am via: JAXA
JAXA) – The Japan Aerospace Exploration Agency (JAXA) conducted a nickname campaign for the first Quasi-Zenith Satellite (QZS-1) between October 16 (Fri.) and December 16 (Wed.), 2009, to familiarize people with the satellite. Among many suggestions, “MICHIBIKI” was selected as the nickname.
Selection result: The chosen nickname is “MICHIBIKI” meaning “guiding” or “showing the way.”
Reason for selection:
“MICHIBIKI” accounted for the highest percentage of proposed names, excluding some names that raised some concerns in terms of third party trademark rights, thus it means the name is supported by many people.
Many godparents of “MICHIBIKI” explained their selection reason as the QZS-1 is to show us a correct location using its accurate positioning information, and to guide us toward a futuristic society by establishing the next generation satellite positioning technology in Japan. As the name precisely illustrates the QZS mission, this name was chosen.
Total: 11,111 (Among them, acceptable applications totaled 10,336, and those who proposed “MICHIBIKI” was 328.)
Application form 4,005
Note) JAXA will send a certificate to all godparents of “MICHIBIKI”
Recently, a positioning service using a satellite has become essential due to the popularization of mobile phones with the GPS function. However, positioning accuracy is often poor because the view of a GPS satellite is hindered by skyscrapers in urban areas in Japan. The major attribute of the QZS is that it can observe Japan from almost its zenith for a long time. Therefore, combined with the existing GPS, the QZS system can provide a high accuracy positioning service even in urban canyons or mountainous terrain.
The QZS system is being developed by JAXA based on the collaboration with Ministry of Education, Culture, Sports, Science and Technology, Ministry of Internal Affairs and Communications, Ministry of Economy, Trade and Industry, and Ministry of Land, Infrastructure, Transport and Tourism (MLIT), and also in corporation with related research organizations namely National Institute of Information and Communications Technology, National Institute of Advanced Industrial Science and Technology, Geographical Survey Institute of the MLIT, and Electronic Navigation Research Institute.
(1) Overcome difficulties that the GPS faces
The QZS will send the almost same signal as that of the currently operated GPS signal and also that of a new-type of GPS, which is under development in the U.S. GPS users can, therefore, receive accurate positioning and information even when they are at a GPS out-of-service area. Thus we can improve the convenience of the positioning service. (GPS complement)
(2) Further boost the GPS
The QZS is to send an accurate correction signal to improve the accuracy of the GPS. By receiving signals from the QZS, GPS users will be able to know more precise position information. Therefore, it is expected that we can conduct very accurate positioning all over Japan. (GPS reinforcement)
|The Quasi-Zenith Satellite System (QZSS) (Quasi-Zenith ,Jun-Ten-Cho, 準天頂 in japanese), is a proposed three-satellite regional time transfer system and enhancement for the Global Positioning System (GPS), that would be receivable within Japan. The first satellite is currently scheduled to be launched in 2010 (|
Michibik or QZS-1). Full operational status is expected by 2013. Este sistema es un WAAS (Wide Area Augmentation System) o Sistema de Aumentación Basado en Satélites.
Este satellite en orbita HEO, dura posicionado sobre el territorio de japon 8 horas por dia
por lo que el sitema requiere al menos 3 de ellos para ser implementado por las 24 horas diarias.
El nombre del primer satelite QZS-1 (lanzado el 12 de septiembre de 2010) es
en Japones bautizado como: Michibiki( 導き),
Que en ingles se traduce como: guidance,
y en chino es “指路”号 Orbit: periodic Highly Elliptical Orbit (HEO). These orbits allow the satellite to dwell for more than 12 hours a day with an elevation above 70° (meaning they appear almost overhead most of the time) and give rise to the term «quasi-zenith» for which the system is named.
Similar orbits are used by the Sirius Satellite Radio system (Tundra orbit). As of June 2003, the proposed orbits ranged from 45° inclination with little eccentricity, to 53° with significant eccentricity. Signals
Because the GPS availability enhancement signals transmitted from Quasi-Zenith Satellites are compatible with modernized GPS signals, and hence interoperability is ensured, the QZSs will transmit the L1C/A signal, L1C signal, L2C signal and L5 signal. This minimizes changes to specifications and receiver designs.
Compared to standalone GPS, the combined system GPS plus QZSS delivers improved positioning performance via ranging correction data provided through the transmission of submeter-class performance enhancement signals L1-SAIF and LEX from QZS. It also improves reliability by means of failure monitoring and system health data notifications. QZSS also provides other support data to users to improve GPS satellite acquisition.
According to its original plan, QZSs was to carry two types of space-borne atomic clocks; a hydrogen maser and a Rb atomic clock. The development of a passive hydrogen maser for QZSs was abandoned in 2006. The positioning signal will be generated by a Rb clock and an architecture similar to the GPS timekeeping system will be employed. QZSS will also be able to use a Two-Way Satellite Time and Frequency Transfer (TWSTFT) scheme, which will be employed to gain some fundamental knowledge of satellite atomic standard behavior in space as well as for other research purposes.