Research On Digital Signal Processing System Of IFOG

As new measurement instruments without mechanical rotation device, Fiber optic gyroscopes (FOG) have aroused much attention in recent years for their potential advantages and prospects, especially have developed in increasingly widespread application of strap-down inertial navigation system. The scale factor, bias stability, angle random walk, are the major indicator to evaluate FOG in the application of medium and higher accurate applications, paper forces on the ways to enhance system performance.First, after expatiating FOG theory in detail, propose digital dual closed-loop systems scheme, which has some merits such as high linear scale factor, high degree of detecting accuracy, broad dynamic range. And we employ the second closed-loop feedback to eliminate reset error, stabilize the phase modulator half-wave and improve system scale factor stability. Then, to design the digital closed-loop FOG hardware implementation structure based on FPGA, analyze the each links of system such as signal detection analog circuit, signal processing circuit and signal driver circuit, we select the proper electronic components, and concern hardly electromagnetism compatibility in the PCB designing. Moreover, the mathematical model of the system is established in the FOG hardware model and the simulation is implemented, then the effect of system parameters on the allover performance such as the system's bandwidth, scale factor, and stability, can be analyzed carefully according to the result. Get the right parameters for fulfill system performance, which provided theoretical guideline for FPGA system designing. Finally, according to the problem of the FOG deadbeat and bias drift induced by electronic crosstalk, the random overmodulation to compensate electronic crosstalk is proposed in the paper. Then software is designed with VHDL language. The experiment result of FOG is presented lastly.