The Reseach For Light’s Length And Dither Control Loop Of Digital Laser Gyro

Digital laser gyro is used for testing the carriers’ senstive angular velocity, its relatvely high measurement becomes an important superiority. As a key component of the strapdown inertialnavigation system, the high-precision digital laser gyro has some important significances on its applications in the innavigation, aviation, aerospace and terrestrial. In order to improve the performance of the digital laser gyro, the internal control circuit has been researched and designed in this paper.First of all, based on the analysis of the laser gyro’s loop control principle, we found some designing problems with consideration of the feedback of practical application.Then, we analyzed the principle of the wrong circuit and re-designed them, which mainly includes the following aspects:1. For reseaching how to use the digtal filter to demodulate the phase signals from the control loop of light’s length control, we designed a Double-T digital filter which has narrow passband and good Single frequency selection effect according to the requirement. The experimental results show that this design has improved the signal-to-noise ratio of modulated signals.2. For reseaching the deburring circuit and phase of ADPLL circuit system in the dither-control loop, we re-designed these circuit according to the gyro performance and debugging of application. It is confirmed that the circuits have meet the designing requirements by the simulations and experiments.3.According to the analysis of the temperature characteristics of digital laser gyro, we created the temperature compensation model, and then designed the temperature compensation circuit with dierent parameters in different temperature part. The mothod of temperature-sections division is used for controlling the compensation data as well as adjusting the parameters. The experimental results show that this design can greatly improve the performance of the laser gyro.Experimental results reveal that these designs not only benefit the actual use, but also reduce the debugging cycle which saves the cost. During the debugging, the signal to noise ratio is increased by200%when we used the Phase signal demodulation circuit, and the bias stability of digtal laser gyro is increased by4～6times by using the compensation circuit in this paper, it has achieved an excellent application effect.