Evaluation on Positioning Accuracy of MICHIBIKI Satellite Ll-SAIF

摘要

GPS signals are interrupted by a building in urban area and the mountain slope. Therefore, the GPS positioning area is restricted. In order to expand of positioning area and raise positioning accuracy, the MICHIBIKI satellite was launched in September, 2010. The MICHIBIKI satellite passed near the zenith in Japan and transmits the almost same signal as GPS. Moreover, MICHIBIKI satellite transmits Ll-SAIF as a reinforcement signal derived from electronic reference point that is operated by GSI, Japan, to raise positioning accuracy. Ll-SAIF signal is so called the sub-meter class and the expected accuracy is less than 1 m.The purpose of this research is to verify the positioning accuracy by an Ll-SAIF signal. In order to verify it, GPS and Ll-SAIF positioning data observed in same time and position were compared. The positioning data observed twice of the morning and an afternoon a day.As the result, for example, GPS accuracy is 3.1674284m in latitude and 3.9034698m in longitude, and Ll-SAIF accuracy is 1.68477m and 1.79976m respectively. This result indicates Ll-SAIF provides high accuracy than GPS. But others result showed, GPS accuracy is 1.56595m in latitude and 1.257894m in longitude and Ll-SAIF accuracy is 4.027356m and 0.916591m respectively.Conclusion are; (1) Ll-SAIF signal were obtain sub-meter accuracy. (2) Almost Ll-SAIF signal were obtained high accuracy better than GPS. (3) In worst case, Ll-SAIF signal were obtained worse accuracy than GPS. The reason is assumed the influence of the East Japan tremendous earthquake. As the electronic reference points were moved by the earthquake, the reinforcement value derived from the electronic reference points might be incorrect.