Research On Missile-Borne GNSS/SINS Integrated Navigation And Positioning Technology

Cruise missiles are often in a high-speed cruise state during work,and the missile-borne navigation system needs to provide accurate navigation information.Our research focuses on the key technology of GNSS/SINS scalar deeply integrated navigation system based on cruise missile,including the improved GNSS signal tracking method and simulation experiments to verify the performance of the whole integrated navigation system on missile.The main research contents of this paper are as follows:Firstly,the basic theory of GNSS and SINS is summarized,and the scalar tracking loop in GNSS receiver is improved for the dynamic characteristics of the carrier.Based on the Kalman filter tracking loop,a tracking loop based on square root cubature Kalman filter and strong tracking filter is proposed.The outputs of In-phase and Quadrature branches are chosen as the observation.The fading factor is introduced into the SRCKF to improve the robustness of tracking loop.This loop can make a unified estimation of code phase and carrier Doppler frequency.The simulation experiments prove that the tracking accuracy of the proposed loop is better and the bit synchronization time of the loop is reduced.Compared with the second-order FLL assisted third-order PLL and EKF-based tracking loop,the root mean square error(RMSE)of code phase is reduced by 47.1% and 12.2%,and the RMSE of carrier frequency is reduced by 40.0% and 11.9%.Furthermore,the time for bit synchronization is shortened by 8.10% and6.56%.Secondly,after comparing and analyzing several forms of SINS aided GNSS tracking loop,an improved SINS acceleration aided GNSS augmented state tracking loop is proposed for the frequency asynchronization error in the auxiliary process.Different from the conventional assistant form of Kalman filter control quantity,this paper extends the carrier Doppler frequency change rate caused by the carrier dynamics calculated by the SINS acceleration as a state quantity into the state vector of the Kalman tracking loop.When the update frequency of the IMU is lower than the update frequency of the GNSS tracking loop,the optimal estimation of the SINS assistance amount can be made in real time to compensate the frequency asynchronization error in the process of the SINS assisted GNSS tracking loop.Simulation experiments compare the performance of four SINS-assisted tracking loops.The results show that the SINS acceleration-assisted tracking loop is less affected by the receiver constant error than the SINS velocity-assisted tracking loop,and the proposed SINS acceleration-assisted state-extended Kalman tracking loop has the best tracking performance,and the tracking stability is improved by 11.82% on average compared with the SINS speed-assisted PLL.Finally,the framework of scalar deeply integrated simulation experiment system is established,and the simulation experiment of missile borne GNSS / SINS integrated navigation system is conducted.The carrier attitude and IMU data are theoretically deduced according to the carrier motion state.The overall scalar deeply combination experiment is carried out with the GNSS signal generated by the simulator and the IMU simulation data according to the trajectory of the cruise missile in the high-speed cruise stage.The results indicate that the GNSS/SINS integrated navigation can correct the cumulative error of SINS and realize the mutual assistance of GNSS and SINS.