Performance Evaluation Of Compact Mems Imu/Gps Tight Coupling With Imu-Aided Tracking Loop

With great demand of navigation products in social life, loosely coupled GPS/INS has been successfully developed in daily life. Although tightly coupled GPS/INS is a robust solution with superior position accuracy to loose coupling, GPS receiver navigation performance are being challenged under signal-attenuated environments since attenuation degrades the ability of GPS to acquire and track signals largely. Hence, it is a trend to improve the robust of GPS signal tracking so as to augment the availability and continuity of GPS receiver in GPS/INS integration.Currently, it is popular to integrate a GPS receiver with a low-cost micro-electro-mechanical system (MEMS) IMU in the navigation product markets. The high points of MEMS, low cost, immediate start-up time and low power consumption, wholly meet the requirements for commercial applications, especially for land vehicle navigation. However, the size depresses MEMS-technology inertial products allowing for a relatively large space occupied by a triad of gyros and accelerometers. Therefore, it is necessary and vital to minimize the size of MEMS IMU so as to be integrated with GPS on a single chip and further develop the compact MEMS IMU/GPS products.This paper puts emphasis on the performance evaluation of MEMS IMU/GPS tight coupling with IMU-aided tracking loop in signal-attenuated environments, such as under foliage areas and in urban canyon areas. Both tracking capability of the aided receiver and navigation accuracy of the integrated system are studied in this research. On the one hand, a detailed analysis of the aiding tracking effects is involved, and then the required bandwidth suitable to guarantee the tracking condition under low signal-to-noise ratio environment is determined. On the other hand, the integration method of a suboptimum IMU configuration with a heading gyro and two level accelerometers is investigated. Then the compact IMU/GPS system and aiding navigation performance are presented and analyzed on tight coupling solution level.