A bimodal approach for GPS and IMU integration for land vehicle applications

In this paper, we present a novel idea to integrate low cost inertial measurement unit (IMU) and differential global positioning system (DGPS) for land vehicle applications. Since the usage of high performance inertial navigation systems (INS) is restricted by their high price and the government regulation, low cost IMU is generally used for most land vehicle applications. However, low cost IMU produces large positioning and attitude errors in very short time due to the poor quality of inertial sensor assembly. More specifically, when GPS information is available, a good navigation solution can be obtained by incorporating DGPS data. However, a reliable result cannot be provided for land vehicle navigation when GPS signal is not available. To conquer the limitation, we present a bimodal approach for integrating IMU and DGPS, taking advantage of positioning and orientation data calculated from CCD images based on photogrammetry and stereo-vision techniques. The positioning and orientation data from the photogrammetric approach are fed back into the Kalman filter to reduce and compensate IMU errors and improve the performance. Experimental results are presented to show the robustness of the proposed method that can provide accurate position and attitude information for extended period for nonaided GPS information.