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On September 11, 2010, the Quasi-Zenith Satellite (QZS) "Michibiki" was launched from the Tanegashima island as the first satellite for positioning in Japan. We have attempted to fix positions using LEX data with centimeter-class augmentation service for centimeter-level positioning augmentation signal via Michibiki. The authors tried to fix positions by using LEX data at a stationary point and in a moving car in real time and with postprocessing. They could confirm no more than 2.22 cm as the average positioning error and discrepancy of postpositioning. K E Y W O R D S GPS, LEX, QZSS, satellite positioningElectron Comm Jpn. 2018;101:3-10.

SUMMARYThe geostationary satellite system will be able to disseminate data to a wider area and a greater number of users simultaneously. The authors tested the network-based RTK-GPS positioning using the area correction parameter (FKP) via the geostationary satellite-based communication line. They investigated network-based RTK-GPS positioning at several fixed points located inside the GPS reference station network area.

ABSTRACT:Seamless positioning techniques in indoor and outdoor environments are necessary for obtaining sensor locations. However, no definitive indoor-outdoor navigation system simultaneously provides high accuracy, high availability and low installation cost. Furthermore, crowded indoor-outdoor navigation systems consisting of multiple techniques will destructively interfere with each other, but an exclusive navigation environment will have difficulty providing stable location services for users. This anticipated issue needs to be investigated with experimental data and simulation results. However, experiments that are deliberately overcrowded with disparate location systems are rare. Therefore, the initial focus in our research was the construction of a test environment for indoor-outdoor seamless navigation experiments. Based on "Standards and Recommended Practices" (SARPs), we focused on accuracy, availability, continuity and integrity to verify the effects of seamless navigation under a combination of as many disparate systems and sensors as possible. We then conducted data acquisition and data analysis in seamless navigation through four integrated experiments. Based on the results of our experiments, we summarize some observations about seamless navigation using multiple navigation systems, and offer examples of the representative issues in our research. We also suggest some directions in indoor-outdoor navigation environment construction for seamless positioning using disparate systems and sensors.