In this paper, a real-time GPS/MEMS-IMU integrated navigation system with a novel DCM based integration method is presented for low-cost navigation applications. An important feature of this novel loosely-coupled integration method we applied is that it is able to detect gyro bias and does not necessarily need the calibration for gyros, which is quite attractive for real-time applications. The applied integration algorithm estimates the Direction Cosine Matrix (DCM) elements instead of Euler angles in the state vectors and uses the total states model in the Kalman Filter (KF). Benefitted from the linear process model for the attitude estimation, the drifting gyro biases can be captured on-line, which consequently leads to a better overall navigation performance. In this paper, the design concept of this integrated system is introduced from an implementation perspective. The system is realized on a DSP platform with direct utilization of the off-the-shelf MEMS-IMU and the commercial GPS receiver which are cost-effective for normal application. With the proposed hardware architecture, a reliable synchronization scheme between the GPS and the IMU is achieved which lays a solid foundation for the integration process later on. Moreover, the system flow is well designed and organized to cope with the increased state vectors and ensure an efficient real-time processing ability for the time-critical nature of such integration system. Field experiments are carried out with a land vehicle to test the implemented system and validate its feasibility. Furthermore, with the real-time data and results, the overall performance of the system is analyzed, as well as the navigation performance.
展开▼
