The Research Of Ultra-Tightly Coupled GPS/SINS Integration System In High Dynamic Conditions

Navigation and positioning in high dynamics is a very difficult problem. Meanwhile, due to the extensive use in military, it is a most critical technology. In some high dynamic environments, such as artillery firing, rocket launching and warcraft flying, acceleration and jerk is very large. The relative motion between GNSS-based receiver and satellite introduce huge Doppler shift and Doppler shift rate into signal. This will result in satellite signal tracking loss of lock, and then navigation and positioning unable to obtain.In this paper, a GPS/SINS ultra-tightly integration system used in high dynamic is proposed. In this system, I and Q measurements, which are obtain from the output of correlators, are used to estimate navigation errors. The errors driving from raw GPS signal can be transformed into IMU data error, under the assist of GPS navigation system, the inherent defect of SINS can be resolved. Since the principle of SINS, positioning error will increasing with time, but the autonomous and the high accuracy in short period of time advantages are very important in Military applications. SINS assist GPS signal tracking loops with high accuracy in short period of time. Doppler shift is derived from the relative velocity which is obtained from SINS output and Satellite ephemeris. Attributed to the high-frequency output of the inertial navigation system, the Doppler-aided GPS signal tracking loops update frequency can reach lk Hz. Under high updates rate, the navigation system can work properly in high dynamics.With the GPS/SINS ultra-tightly integration technology, more accuracy positioning and the better system performance in high dynamics will be reached.This paper analyzes the existing GPS/SINS ultra-tightly integration technologies comprehensively, and divides them into three categories. Furthermore, advantages and disadvantages of each integration ways are pointed out. Based on this, the GPS/SINS ultra-tightly integration system architecture suitable for high dynamics is designed. Due to the non-linear characteristics of system model, SUKF nonlinear filtering algorithm is used to estimate system errors. Finally, the algorithm proposed in this paper is verified in two ways. Surrounding this, the GPS IF data simulation software and GPS RF front-end are developed.The key technologies and innovative points of this paper are summarized as follows:(1) Ultra-tight integrated navigation technology is employed to solve the problem of navigation and positioning under high dynamics;(2) A new ultra-tight integrated navigation technology classification is proposed, and the strengths and weaknesses of them are analyzed;(3) Ultra-tight integrated system suitable for high dynamic environments is proposed;(4) SUKF nonlinear filtering algorithm is employed to process navigation system model under high dynamics.