Research On Signal Processing System Of Closed-Loop Fiber Optic Gyroscope

Fiber optic gyroscope is a new angular rate sensor based on the Sagnac effect. It has many advantages such as large dynamic range, high sensitivity, high reliability, long life, easy integration, etc. Since it first came out, countries have attached importance to the fiber optic gyroscope in the world. So far, fiber optic gyroscope has been widely used in many military and civilian areas. And it will have a very broad development prospects in the near future. At preset, fiber optic gyroscope becomes the research focus in the field of inertial devices.Firstly, recent development and applications of fiber optic gyroscope in China and abroad are introduced, in this paper. The principle and basic composition of the fiber optic gyroscope is systematically reviewed. This paper deeply analyzed main factors which affect the accuracy of fiber optic gyroscope. The above job laid a theoretical foundation for the next step.All digital processing program of closed-loop fiber optic gyroscope is determined, though the study of correlation detection and phase modulation. In this paper, digital demodulator is used to detect error signal of fiber optic gyroscope; digital phase ramp wave and square wave bias are used to control feedback; and digital filter is used to reduce noise. Various noise which affcet the propety of fiber optic gyroscope are analyzed in detail and preliminary solutions are introduced. Based on this, a self-adaptive filtering method called variable step-size Least Mean Square (LMS) algorithm was presented, which is the improvement of LMS algorithm. Experiment results indicate that the method has a faster convergence speed. It's a new method with superior filtering stability, realtime performance and accuracy, which is easy to implement.In the end, the design of digital signal processing systems of closed-loop fiber optic gyroscope is described in detail. Analog circuit consists of four parts:preamplifier, A/D converter, signal processing and D/A converter. And design of the four parts is described in detail. In digital circuit, FPGA is used as the core device to complete all digital signal processing independently. Apart from design, this paper also described the implementation of each unit, include:timing control, digital demodulation, modulation signal, digital filter, serial communication. At last, the whole system is tested and analyzed.