Temperature Control System Optimization Design Of Strapdown Airbone Gravimeter

Airborne gravimetry is an effective method to obtain precision and large area information about gravity by aircraft. The quartz flexible accelerometers and laser gyros are the core sensors in the strapdown airborne gravimeter, which have obvious temperature characteristic. In order to ensure measurement accuracy of the system, use the method of temperature control to improve the measurement accuracy of the sensors. Based on airborne gravimeter invented by national university of defense technology, the paper studied the temperature field of airborne gravimeter, temperature control method, the output characteristics of core sensors under precision temperature and the optimization of temperature system. The main work is as follows.1. The effects of temperature on system are analyzed. Heat analysis about the airborne gravimeter is done by finite element simulation software ANSYS. Based on the simulation result and the semiconductor device characterization, the radiator and the heat isolate design used in external temperature control system was decided. The steady-state temperature field analysis result is used to decide the location of measurement points, the transient temperature field analysis result is used to determine the heat transfer conditions in internal temperature control system, and using actual data validate the correctness of heat analysis.2. Based on the exhaustive analysis of system, a new internal heater layout and new external heater exchange structure are given. Through simulation, the effectiveness of the optimization suggestion is confirmed.3. Using the heat transfer theory, the heat transfer model of multi-stage temperature control system is obtained, on the basis of the qualitative analysis pointed out that the temperature control system should be designed considering all kinds of the system thermal parameters. By system identification, the transfer function of the external temperature control system and state space model of the internal temperature are obtained. PID controller tuning methods and the time-delay systems control algorithm were studied.4. Detailed analyze the data of airborne gravity temperature control system, the analysis verify the accuracy of temperature control system can ensure measurement accuracy of the airborne gravimeter. Analysis the output characteristics of the core sensors under precise temperature control system, studies have shown that under precise temperature control, the output of accelerometer has obvious drift over time and this drift have good reproducibility, which use the method of compensation to eliminate.