Study Of I-FOG Signal Processing And Detection

In this paper, interference fiber optic gyro (IFOG) is considered as the research object, the important theories and the critical technology for IFOG is discussed and analyzed Systemically based on extensive reading and deep study by the author.Firstly three important optical principles about IFOG Sagnac effect, principle of light interference, principle of light reciprocity are discussed systemically. They are the solid foundations of the theory of electro-optic signal measurement for IFOG. In the part of photoelectric signal detection and processing of the modern IFOG, three aspects of research are done. They are: reciprocity phase modulation, closed-loop technique, correlation detection technology.1. In the part of reciprocity phase modulationFirstly reciprocity phase modulation technique which is used in modern IFOG widely is analyzed. Principles of sine-wave and square wave reciprocity phase modulation technique, interference factors, production and elimination are discussed. On this basis, model of phase modulation is built with Labview. The technique of triangle wave reciprocity phase modulation is put forward. Simulation is done to verify this idea with Labview and FPGA.2. In the part of closed-loop techniquePrinciple of closed-loop technique is analyzed. Second-feedback technique and overcome of dead-time effect are studied. By comparing open-loop technique with closed-loop technique, this paper highlights the superiority of closed-loop technique. The feedback mechanism of all digital closed-loop technique is studied, and pointed out that the step wave can realize closed-loop control in reset stage due to the calculation features of the registers in digital circuit, omits the complicated secondary compensation.3. In the part of correlation detection technologyThe paper discusses correlation detection technology in detail. Photoelectric detection is the necessary technique in I-FOG. Since amplitude of photoelectric signal is extreme weak, more over, its immersion in the noise, correlation detection technology is the effective photoelectric signal detection technology. The liminations and typical application of correlation detection technology-lock-in amplifier are studied.