The Research Of Parallel Strapdown INS Transfer Alignment Algorithm For High Dynamic Conditions

Transfer Alignment is the process of initializing a slave inertial navigation system(INS) using navigation data from the master navigation system. The process is accomplished by an one-shoot-transfer, then calculating the difference of navigation solution between the slave and master INSs to estimate the desired errors by a kalman filter or some other state estimator.Initial alignment error is one of the main navigation error derivations, especially in high dynamic conditions. In order to get a high navigation solution accuracy, increasing the navigation computation speed is a good method. In this thesis, a parallel strapdown INS transfer alignment algorithm is proposed to solve the problem of low navigation accuracy in high dynamic conditions cause by the computer calculation capability using FPGA's strong parallel calculation feature.The strapdown inertial navigation system is introduced first. And then, In this thesis, transfer alignment technology and its matching methods are introduced, the effect of initial alignment error on navigation solution accuracy is analyzed, several simulations on transfer alignment are exhibited simultaneously. A parallel navigation computation algorithm is proposed, the analysis of this parallel algorithm shows that the design significantly increases the updating rate of the navigation computation; An FPGA architecture is proposed to implement the parallel navigation computation algorithm; a design of FPGA-based parallel kalman filter used in velocity and attitude matching transfer alignment using systolic array technology is proposed, to solve the problem of gigantic computation of kalman filtering algorithm; At last, an FPGA-based implementation experiment is performed to analyze and comfirm the the validity of the parallel transfer alignment algorithm.The main innovations of this thesis are listed as follow:(1)Proposing a parallel strapdown inertial navigation algorithm to meet the accuracy requirement of the navigation computation for high dynamic conditions.(2)Proposing a FPGA-based implementation method of parallel strapdown inertial navigation algorithm, and implementing the design on a Xilinx Virtex5 FPGA.(3)Using Faddeeva algorithm and systolic array technology and matrix complement method, a FPGA-based one dimension systolic array-based architecture is applied to implement the kalman filter in velocity and attitude matching transfer alignment. This architecture can improving the kalman filter updating speed, and reduce the FPGA resource ultilization at the same time.