Performance assessment of a low-cost inertial measurement unit based ultra-tight global navigation satellite system/inertial navigation system integration for high dynamic applications

摘要

Owing to large Doppler shifts, the signal of global navigation satellite system is difficult to be acquired and tracked by a receiver for high dynamic vehicles, such as missiles, aircrafts and spacecrafts. Hence, the inertial navigation system is usually used to aid the acquisition and tracking. Compared with the traditional scale tracking, the vector tracking has better performances in the navigation robustness and the immunity to interferences. Although the vector tracking aided by a low-cost inertial measurement unit (IMU) is not as good as the one aided by high-grade IMU in the tracking performance and stability, the low-cost IMU based vector tracking loop has lower price, smaller size and lighter weight. Hence, it is valuable to reduce the expense of ultra-tight integration system. In this paper, an ultra-tight integration system using the low-cost IMU based vector tracking is proposed to achieve the vector tracking and navigation for high dynamic applications. As the critical factor in the ultra-tight integration, the Doppler frequency shift is estimated and compensated to achieve the acquisition and tracking of every satellite. Then, a vector tracking Kalman filter is designed to implement the vector tracking and integrated navigation. To verify the effectiveness of the ultra-tight integration, an experiment system is built and a high dynamic scenario is simulated. The results prove that the designed ultra-tight integration system has perfect tracking and navigation performances for high dynamic applications.