Development and Assessment of a Low Dynamic Vehicle Navigation System

S. Moafipoor, L. Bock, J.A. Fayman, G. Mader, P.J. de Jonge

Abstract:	There is a need in military operations for reliable, highaccuracy, and low-cost vehicle navigation systems for use in both manned and unmanned ground and air vehicles. Geodetics' Geo-LDV product is an integrated GPS/INS navigation system providing real-time, high-accuracy Time Space Positioning Information (TSPI) in a low-cost, light-weight ruggedized package. Positioning accuracy in the Geo-LDV is achieved through the use of dual-frequency carrier phase differential GPS solutions provided by Geodetics' Epoch-by-Epoch® (EBE) technology. EBE performs Precise Instantaneous Network (PIN) positioning utilizing data from one or more GPS reference receivers and the vehicles on-board GPS receiver to produce a rigorous network solution at each measurement epoch. Unlike traditional differential GPS approaches, there is no need for re-initialization immediately following loss-of-lock problems, such as occurs when GPS satellites are occluded from the antennas view. This feature of instantaneous integer ambiguity resolution is of utmost importance when trying to position dynamic platforms operating in environments where GPS reception is lost and regained often, such as in urban terrain or a maneuvering military aircraft where GPS becomes blocked by airframe masking. EBE generated GPS solutions are integrated on-board the Geo-LDV with data from a 6-DOF IMU using a loosely-coupled Extended Kalman Filter (EKF). The function of this integration is to propagate the strapdown attitude, inertial velocity and position using the IMU angular rate and acceleration outputs, incorporating EKF corrections. However, since this integration is sensitive to the systematic errors of the IMU, correct modeling of IMU errors is essential for achieving high-accuracy TSPI. In this paper, we focus the approach used in the Geo-LDV for modeling IMU errors. The approach was implemented in an IMU calibration tool box. We present results obtained when the toolbox was used to calibrate several IMU's supported by the Geo-LDV platform.
Published in:	Proceedings of the 2011 International Technical Meeting of The Institute of Navigation January 24 - 26, 2011 Catamaran Resort Hotel San Diego, CA
Pages:	895 - 907
Cite this article:	Moafipoor, S., Bock, L., Fayman, J.A., Mader, G., de Jonge, P.J., "Development and Assessment of a Low Dynamic Vehicle Navigation System," Proceedings of the 2011 International Technical Meeting of The Institute of Navigation, San Diego, CA, January 2011, pp. 895-907.
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