Using Pressure Sensors for Altitude Aiding with a Multi-constellation GNSS in Urban Environments

H. Tokura and N. Kubo

Abstract:	Diver safety become highly required for the Intelligent Transport Systems (ITS). To avoid collisions, the vehicles, precise position becomes key technologies. This study focused on determining vehicles traveling lanes using altitude information. GNSS precise positioning such as RTK can provide accurate absolute 3-dimentionl position. However, obtaining accurate vertical information by GNSS positioning is difficult under urban environment cause of severe multipath. In this paper, barometric pressure sensor was used for altitude aiding with consumer grade GNSS position. Using Barometric pressure sensor, we are easily able to obtain atmospheric pressure, on the other hand difficult to obtain absolute altitude. To solve these issues, the following investigation was performed. Firstly, we evaluated the basic performance of barometric pressure sensor. As for the calibration, we used two datum. One is meteorological pressure data provided by the Japan meteorological agency for calibrating atmospheric changing. Another one is ellipsoidal height data provided by RTK-FIX solutions for calibrating absolute height at the initial timing. To confirm the accuracy of altitude information provided by sensors, kinematic test by vehicle were performed in urban environments. As for the results, altitude provided by sensor was more stable and available than provided by GNSS. It reveals that altitude aiding by the sensor is effective for determination vehicle lanes. There is another possibility that more frequent calibration by the RTK-FIX solution are performed for sensor data, we are able to obtaining more accurate altitude. However single frequency RTK-FIX solution generally contains lots of wrong fix solutions that have to be removed for the calibrating. Detecting reliable solution in the RTK-FIX solution methods were investigated. It reveals that in the static and kinematic conditions, poor numbers of satellites cause large wrong FIX solutions. According this results, limitation of the number of satellites improves FIX solutions reliability. In addition, these limited solution’s time intervals became short enough for calibrating.
Published in:	Proceedings of the 28th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2015) September 14 - 18, 2015 Tampa Convention Center Tampa, Florida
Pages:	1 - 7
Cite this article:	Tokura, H., Kubo, N., "Using Pressure Sensors for Altitude Aiding with a Multi-constellation GNSS in Urban Environments," Proceedings of the 28th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2015), Tampa, Florida, September 2015, pp. 1-7.
Full Paper:	ION Members/Non-Members: 1 Download Credit Sign In