Realization of Fiber Optic Gyroscope Signal Processing Circuits Based on FPGA
|School||Harbin Institute of Technology|
|Course||Control Science and Engineering|
|Keywords||fiber optic gyroscope feedback of step wave signal detection closed-loop control|
Gyro is a kind of important inertial sensor, and it is a basic part of navigate-on orguidance. The fiber optic gyro (FOG) which is based on Sagnac effect has some special advantages which other gyros cannot replace.Firstly, the principle of FOG is briefly addressed in this thesis. FOG phase modulation theory, square wave modulation scheme, and analysis of closed-loop fiber optic gyros step wave modulation and principle are discussed. Open-loop and closed-loop FOG fiber optic gyro are mpared to prove that the closed-loop fiber optic gyro system is of superiority.FOG system is modeled and closed loops are designed and simulated. By simulation, the parameters in closed loops are determained to meet the system requirement. In order to restrain system error caused by parameter perturbation due to ambient temperature changing, a second losed loop is introduced in step wave phase modulation. Designg FOG closed-loop detection scheme, includes front end interference signal detecting converter, driving feedback converter and digital step wave feedback.Finally, all of the digital signal process functions in FOG are realized by FPGA (Field Programmable Gate Array), this thesis introduces the design of FOG closed-loop system in digital unit, includeing system clock module, digital demodulation module, generator of modulation signal module, 2πreset module, and UART module. Analysis of the filter of FOG signal processing is given out for the follow work in the future.