| Strapdown inertial navigation system(SINS)is a dead-reckoning navigation system of which the performance depends heavily on the accuracy of the initial alignment.Transfer alignment also belongs to a kind of initial alignment technology.Due to space and cost,the device precision of SINS sub-inertial navigation limits its self-alignment accuracy,With the help of high accuracy navigation information of main INS,the difference between navigation information of main INS and sub INS can respond to different degrees of misalignment between main and sub INS.by establishing the error model of Kalman filtering calculation,the misalignment angle between the main INS and sub INS can be got.Then high precision alignment of sub INS can be realized.The purpose of this paper is to study transfer alignment technology in vehicle and marine environment,find a suitable transfer alignment matching method in two environments,and study its alignment accuracy under real conditions.On the basis of analyzing a large number of research results both at home and abroad,the paper chooses the current speed matching,attitude matching and speed plus attitude matching transfer alignment to do research.Through the study of transfer alignment error equation,kalman filter technology and two ways of realizing transfer alignment,the state space models of three matching are completed.Combined with the actual maneuver conditions of the vehicle and marine environment,the digital simulation of the three matching methods is carried out.Subsequently,a transfer alignment integrated information processing device based on FPGA and DSP dual processor is designed.The upper PC software is compiled,and a set of transfer alignment test platform is set up.The results of the research are verified by the laboratory test,the swing table test,the vehicle test and the sea test.It can be concluded from the simulation results,the alignment speed and accuracy of the velocity plus attitude matching is better than the other two kinds of matching methods,the real test results also verify the correctness of the simulation results.In the real test,the estimated error of the horizontal angle is less than 2';In vehicle test,the installation error angle estimated results of three attitude angles has been convergence in the 10 s after the end of the maneuver,the maximum error of azimuth angle is 5.17';in the sea test,the maximum error of azimuth angle is 13',and the convergence speed depends on the sea level.Under the 3 level sea condition,the horizontal convergence time is about 5s,and the convergence time of the azimuth is less than 15 s.The results show that,in most cases,the velocity plus attitude matching can achieve rapid transfer alignment effectively in vehicle environment and marine environment.The transmission alignment integrated information processing device is easy to install,low cost,low power consumption,and has high engineering practicality. |
