An experiment for a 2-D and 3-D GPS/INS configuration for land vehicle applications

Systems using GPS and IMU sensors integrate the measurements to determine position, velocity and attitude of a vehicle used for various applications in air, marine and land. There are some unique differences in the land applications over the air and marine applications, such as occasional larger turn in yaw angle and only a small fluctuation in the other two axes of orientation. Under these conditions a simplified system for some land applications with a single gyroscope aligned vertical to measure yaw rate and an accelerometer or a vehicle odometer for vehicle forward linear motion may suffice and small fluctuation on roll and pitch values and corresponding accelerations ignored. This configuration reduces system cost and simpler processing. To understand what accuracy can be obtained using such a system, this paper first presents simple formulas used in 3D and 2D sensor configuration. The formulas are then used to evaluate errors in position from ignoring the small quantities. The magnitude of errors can help to make a decision for a choice of a 2D or 3D system to meet the accuracy sought. Experiment to get difference in position from actual results using 3D system results with the data from the same system derived in 2D mode is also important and it is under evaluation.