Research into the Application of Integrated RTK-GPS/INS Systems for IT Construction

Koji Fujimoto, Hirotoshi Matsushita, Yutaka Shimogaki, and Makoto Tanigawara

Abstract:	This paper discusses applications of RTK-GPS positioning for land vehicles using the QZSS. RTK-GPS provides precise positioning in the order of centimeters, but it is difficult to use this technology in mountainous or urban regions where satellite signals are frequently obstructed. The purpose of this study is to improve the continuity and the reliability of RTK-GPS. RTK-GPS integrated with an Inertial Navigation System gives continuous, precise positioning, even when the number of visible GPS satellites is insufficient due to signal blockage and attenuation. First, the Kalman filtering schemes of Static and In- Motion Alignment methods to estimate the initial attitude and heading of the INS are discussed. Next, the RTKGPS/ INS integration schemes that complement the inherent drawbacks of each system are examined. In this examination, two methods are considered: one is the Loosely Coupled method, the other one is the Tightly Coupled method. In this study, it was found that the In-Motion Alignment method with the low cost INS was able to estimate attitude with an accuracy of 0.04 degrees and estimate heading with accuracy of 0.34 degrees. Also, it found that the Tightly Coupled method maintained 10cm accuracy for more than one minute when the number of visible satellites was below four. The simulation showed that In-Motion Alignment with RTK-GPS and low cost gyros can determine initial attitude and heading with an accuracy acceptable to apply to a construction vehicle. Moreover, it was confirmed that the Tightly Coupled method could sustain highly precise positioning in a place where the satellite signal environment was poor. The results of this study proved that an integration system consisting of a RTK-GPS receiver and a low cost INS could get three-dimensional positions and attitudes of the vehicle.
Published in:	Proceedings of the 2007 National Technical Meeting of The Institute of Navigation January 22 - 24, 2007 The Catamaran Resort Hotel San Diego, CA
Pages:	436 - 445
Cite this article:	Fujimoto, Koji, Matsushita, Hirotoshi, Shimogaki, Yutaka, Tanigawara, Makoto, "Research into the Application of Integrated RTK-GPS/INS Systems for IT Construction," Proceedings of the 2007 National Technical Meeting of The Institute of Navigation, San Diego, CA, January 2007, pp. 436-445.
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