Robust Attitude Determination Using GNSS Multi Baseline Carrier Phase and IMU Sensor Fusion

Hiraku Nakamura, Hiroyuki Toda, Naomi Fujisawa, and Takuo Kashiwa

Abstract:	This paper shows the architecture of robust attitude determination using the constellations of multiple baselines with multiple GNSS receivers and antennas. This architecture includes two novel methods. One is an algorithm to achieve initialization of attitude determination fast and the other is an algorithm to output orientation continuously with high accuracy even when only 1 satellite is available. Using the constellation of multiple baselines and inclination information of the IMU (Inertial Measurement Unit), the initialization algorithm, can estimate the integer ambiguity only by observed information of a single epoch without continuous observation of the carrier phase signal which is necessary for estimation of the floating ambiguity. By this method, attitude determination can be performed robustly and fast. Regarding the continuation algorithm of orientation, estimated clock delays among synchronized GNSS receivers can realize a tight coupling of the single difference (time difference of the carrier phase signal among GNSS receivers) and the IMU. In addition, it is possible to guarantee diversity in the arrival directions of satellite signals by a plurality of isotropically arranged baselines, and continues the orientation even when only 1 satellite is visible. Evaluation using the prototype confirmed that it is possible to determine the attitude at high speed even in the environment with a satellite blocking rate of 50%. Furthermore, authors confirmed that the orientation accuracy (standard deviation) is 1 degree even in urban environments. In 2018, operation of the 4 satellite constellation of QZSS (Quasi-Zenith Satellite System) will be started in Japan. Therefore, 1 satellite is secured in Japan even the urban environment, the robustness of this architecture is expected more.
Published in:	Proceedings of the 30th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2017) September 25 - 29, 2017 Oregon Convention Center Portland, Oregon
Pages:	3102 - 3110
Cite this article:	Nakamura, Hiraku, Toda, Hiroyuki, Fujisawa, Naomi, Kashiwa, Takuo, "Robust Attitude Determination Using GNSS Multi Baseline Carrier Phase and IMU Sensor Fusion," Proceedings of the 30th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2017), Portland, Oregon, September 2017, pp. 3102-3110. https://doi.org/10.33012/2017.15227
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