Research On Digital And Analog/Mixed Signal Simulation Of Fiber Optic Gyroscope Signal Processing Circuit

Fiber Optic Gyroscope (FOG) is a high precision inertial sensor, consisting of fiber loop,analog signal circuit and digital signal circuit. The precision of FOG and shift are affected by various error factor, which is including nonreciprocity error of FOG, circuit error,assembly technology etc. Analog and digital signal circuit is verified respectively using professional simulation tools in system design. But integrated verify of digital and analog/ mixed signal circuit for FOG is hard to settled. So the method of digital and analog/mixed modeling and simulation is proposed for FOG to simulate optical transmission signal, analog circuit and digital circuit collaboratively. The details including:Firstly, the basic principle of interface FOG is elaborated briefly from sagnac effect and reciprocity structure. Digital closed FOG structure and the principle of each component are introduced. There have various achievements for FOG, angular velocity demodulation of four stage wave modulation and demodulation, step feedback, gain error demodulation and 2?reset etc are analysed mathematically in detail.Secondly, the development and technology implementation of digital and analog/mixed simulation is elaborated deeply. There are various solution for digital and analog/mixed simulation,SystemVision(ADMS) of Mentor Graphics corporation is selected and used as system simulation tool after comparison among solutions, according to the characterize of FOG and condition in lab, and VHDL-AMS, SPICE and Verilog-AMS modeling language are gradually introduced.Thirdly, analog signal component and mixed signal component composed system are modeled respectively by using VHDL-AMS; the part of digital signal modulation and demodulation are modeled by using VHDL. FOG system is modeled by multilayer instantiation mechanism from top to down.Finally, advanced simulation analysis is processed for each link and construction section of FOG system by the FOG system mixed signal model. Simulation results show the FOG system is a typical one order control system. Dynamic Characteristic of FOG is simulated under step, slope and sine input angular input angle velocity, which result indicates output angular velocity can track input angular velocity. The affect relationship for the key circuit parameters to the FOG system are pointed out by simulation. In addition, strong shock and temperature are major effect factor to FOG system, and the relationship of these environment factors affect to the FOG system are analysis by mixed signal simulation.Digital and analog/mixed signal modeling and simulation for FOG is contribute to the design of FOG system, the problem of blind engineering commissioning can be effectively solved and production efficiency is improved.