Generation and Evaluation of QZSS L1-SAIF Ephemeris Information

Takeyasu Sakai, Hideki Yamada, Sonosuke Fukushima, and Ken Ito

Abstract:	QZSS (quasi-zenith satellite system) is a Japanese satellite navigation program with a regional service coverage. The orbits for QZS (quasi-zenith satellite) are 24-hour elliptic orbit inclined 43 degrees in order to broadcast radiosignals from high elevation angle into urban canyons. With a full constellation of QZSS, one of QZSS satellites always exists at around the zenith so that it helps the first acquisition of navigation signals and quick start of GNSS receiver as well as it provides GPS-like and SBAS-like ranging signals. The first QZSS satellite, QZS-1 “Michibiki”, was launched successfully on 11th Sept. 2010 from Tanegashima Space Center, Japan, and settled to the intended inclined elliptic orbit. By the end of November, initial functional checkout for satellite bus and mission equipment was completed without any major problems. Since then, technical validation experiments have been conducted by some participating organizations. QZSS is broadcasting GPS augmentation information on the GPS L1 frequency for experiments. For this purpose L1-SAIF (submeter-class augmentation with integrity function) signal has been developed based on SBAS standard. The ENRI has been responsible for development of L1-SAIF Master Station (L1SMS) for the experiment. It was successfully developed and tested with expected performance. Following initial functional checkout, the initial experiment has been conducted using a combination of QZS-1 on orbit and L1SMS. RF characteristics of L1-SAIF signal is identical with GPS L1 C/A signal so that L1-SAIF can be used for ranging. For this purpose, it is necessary to broadcast ephemeris information on L1-SAIF signal. The authors have designed Message Type 58 for broadcasting ephemeris information on L1-SAIF and implemented MT58 generator for the L1SMS. In this paper it is reported that MT58 is generated successfully and it is confirmed that the message brings ephemeris information to L1-SAIF users with enough accuracy.
Published in:	Proceedings of the 24th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2011) September 20 - 23, 2011 Oregon Convention Center, Portland, Oregon Portland, OR
Pages:	1277 - 1287
Cite this article:	Sakai, Takeyasu, Yamada, Hideki, Fukushima, Sonosuke, Ito, Ken, "Generation and Evaluation of QZSS L1-SAIF Ephemeris Information," Proceedings of the 24th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2011), Portland, OR, September 2011, pp. 1277-1287.
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