Design On Fiber Optic Gyro Land Vehicle Navigation System

Strapdown Inertial Navigation System (SINS) has inertial sensors directly mounted onto the vehicle, and physical platform is replaced by mathematical platform. In contrast to flat inertial navigation system, SINS has many great advantages. The Fiber Optic Gyro (FOG) is suitable for working under adverse operating conditions, because of its absolute solid state, quick-reaction, large dynamic scope, simple structure, low weight, longevity and so on, and these characters are extremely needed for SINS. The SINS based on FOG has a good prospect of application due to these advantages. This paper studies the design and realization of a new kind of Land Vehicle Strapdown Inertial Navigation System (LVSINS ) based on FOG.This paper firstly introduces the basic principle of FOG and the element theory of SINS. Quaternion algorithm which is extremely efficient and easy to be implemented is adopted due to analysis and comparison of some SINS attitude algorithms, and four-order Range-Kutta algorithm is used to solve algorithm equations. Two-position north seeking algorithm used for system initial calibration is studied, which has several advantages such as high precision, short seeking time, small drift error.Data acquisition module is mainly studied and designed. Data acquisition precision of FOG and accelerators is one determining factor to influence system navigation performances, so the performance and anti-interference of data acquisition module are highly required. As a result, two methods are brought out: one is V/F conversion method which is mainly composed of synchronous voltage-to-frequency converter AD652; the other is A/D sampling method which is mainly composed of 16 bit analog-to-digital converter AD676. After north seeking experiments, the A/D sampling method is used because of higher performance.The system control core is composed of DSP chip TMS320F2812 and FPGA chip XCS20XL, and navigation computer uses Industrial Personal Computer PC104. The hardware electric circuits related of DSP, FPGA and serial communication are respectively designed. The software procedures of PC104, DSP and FPGA are written.Finally, all angle north seeking experiment, high and low temperature north seeking experiment, attitude precision experiment and land vehicle navigation experiment are carried out. The test data shows that performances of the system designed absolutely satisfy the project technical requirements.