| Budget Amount *help |
¥2,600,000 (Direct Cost: ¥2,600,000)
Fiscal Year 1997: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1996: ¥2,000,000 (Direct Cost: ¥2,000,000)
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| Research Abstract |
A domestic positioning system using geostationary satellites in Japan has been propose by the present authors. It was proved that high accurate positioning was possible, though the post processing, by exploiting TV synchronous signals transmitted from broadcasting satellites for range measurement. In order to attain a real-time positioning at mobile stations, the satellite position information must be sent to users. The authors tried to use a communication satellite to transmit them. At the same time, they also tried to use the communication satellite as a transmitter for positioning as well. Thus, it is necessary to obtain the exact position of the satellite. They tried to establish a system to monitor and transmit the position of communication satellite by VSAT (Very Small Aperture Terminal) for real-time positioning. A 31- bit m- sequence signal of 64 kHz was used as a range finding signal to the geostationary communication satellite JCSAT-1 at 150 E.In the proposed system, the satellites position was deduced from three ranges between the satellite and three VSAT earth stations. They were measured at the master station by switching the reception frequency to receive range finding signals sent back from the satellite directly and the two slave stations through the satellite. The measured absolute ranges at the master station agree well with the values simultaneously measured at the satellite control center and have the standard deviation of 2m.
We tried the positioning with three geostationary satellites, namely BS at 110ﾟE,CS at 162ﾟE,and JCSAT at 150ﾟE in the third year. The technique, developed in the first two years was used. The deduced points, of which the 2 drms is 72 m, by the present positioning method scattered widely in the latitudinal direction as the components of the covariance matrix, which is deduced from the satellites allocation, imply.
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