Realization Of Fiber Optic Gyroscope Signal Processing Circuits On FPGA

The interferometric fiber optic gyroscope (I-FOG) is a solid state optical gyroscope, which is based on Sagnac effect. Compared with traditional mechanical gyroscope, I-FOG brings with it the advantages of lighter weight, longer lifetime, higher reliability and wider dynamic range, which is regarded as the best choice to strap down inertial navigation system and has found a wide application in many fields.Firstly, the principle of I-FOG is briefly addressed in this paper,I-FOG to the various devices were introduced, and then discussed the FOG phase modulation theory, the square wave modulation scheme, Then a detailed analysis of closed-loop fiber optic gyros saw modulation and principle. As well as open-loop and closed-loop FOG fiber optic gyro, compared to prove that the closed-loop fiber optic gyro systems superiority.Secondly, by an analysis of closed-loop fiber optic gyroscope system signal transmission model, the closed-loop fiber optic gyroscope digital signal processing systems was described,then Analysis of the correlation detection loop FOG weak signal detection to reducing noise.Thirdly, I-FOG system is modeled and double closed loops are designed, delay was full considered in design. To restrain system error caused by parameter perturbation due to ambient temperature change, a second closed loop is introduced, and designed the second loop feedback.At last, the paper describes the analog unit and the digital unit of the I-FOG which all digital signal processing task being accomplished independently by FPGA. Analog circuit in detail the various modules of the design ideas and methods, The analogue circuits include Input signal processing circuit , signal amplifier, A/D converter circuit, D/A converter circuit, FPGA configuration circuit. The digital system of closed-loop IFOG consists of data receiving asynchronous FIFO module, filter module, Digital demodulation module, control module, Modulation signal generator module, UART Module.