Research Of Data Collecting Technique And Algorithm In Strapdown Inertial Navigation System

Strapdown INS is a type of Inertial Navigation Systems. Compared with Platform INS, Strapdown INS has the advantages of low volume, low weight, low cost and high reliability. Strapdown INS leads the trend of INS. The thesis, based on sensors of I-42 Strapdown INS, deals with technique of data-collecting, attitude-updating algorithm and velocity-updating algorithm of Strapdown INS in order to pave the way for further research. Primary work done is as follows:Design of data-collecting electronic circuit of the Strapdown INS as well as relevant driver.FPGA described by VHDL language serves as the core of hardware of the data-collecting electronic circuit.It completes the function of communication between inertial instruments and navigation computer. The experimentation of the data-collecting system shows that the basis and design of the system is feasible. In accordance with modularization of software engineering theory, C language is adopted on the DOS platform to develop the program, so as to lay a foundation for embedment in the future.Study on attitude-updating algorithm. Study on attitude-updating algorithm based on quaternion and rotation vector. Primary research is on the basis of coning compensation in the course of updating the rotation vector. Optimal N-sample rotation vector algorithm and recurrent algorithm are proposed. The compensation performance of different algorithms were compared with each other through emulator.Study on velocity-updating algorithm.Under the environment of sculling,all the algorithms are optimized in order to minimizing the excursion rate.A new means of deducing sculling compensation by coning compensation method is introduced. According to the analysis of the high and low frequency parts in the equation of integral specific force,a precise velocity error correction algorithm is presented. The compensation precision of different algorithms were analyzed.