Study And Design Of Digital Closed-loop Fiber-optic Gyroscope Based On FPGA

Fiber-Optic Gyroscope’s basic principle is measuring the Sagnac phase difference causedby the angular movement, then getting the input angular velocity by phase difference. Thedigital closed-loop Fiber-Optic Gyroscope has the advantages of long service life, highreliability, high starting speed, wide dynamic range and other advantages, so it has beenwidely used in many precision fields. The excellent properties of FPGA technology provideadvantages for digital closed-loop Fiber-Optic Gyroscope technology. In this work，wedesigned a digital closed-loop Fiber-Optic Gyroscope based on FPGA technology. It can beapplied to the angular velocity measurement on civil field. The digital closed-loop Fiber-OpticGyroscope consists of optical system and control system. The optical system comprises a lightsource, a detector, optical fiber coupler, a optical waveguide and so on. The control system ismainly to achieve the digital phase detection，signal modulation, signal feedback and dataoutput. The core chip of the control system is FPGA. The main function of FPGA areproviding the clock signals for system, realizing digital demodulation, outputting data andrealizing the closed loop feedback. Based on the above design, we completed the circuit’sdrawing and debugging，PCB board’s drawing and making, programming with Verilog HDLand debugging. The produced digital closed-loop Fiber-Optic Gyroscope is circular in shape，diameter of9.55cm. The digital closed-loop Fiber-Optic Gyroscope was powered, and theprogram downloaded to the gyroscope. Then we measureed the the scale factor, scale factorasymmetry, scale factor nonlinearity, zero bias, bias stability to prove the gyroscope workingproperly.Finally, coming up with the method to improve the performance andapplication development trends and related technology of fiber optic gyroscope in other ways.