Applied Research Of Using Fiber-optic Ice Sensor In Meteorologic Icing Detection

Meteorologic factor for icing is defined as the weather conditions which determine the extent of aircraft icing. With the development of ice detection, it supplies a new way for detecting the potential area of coming icing to researching the relationship between the ice information and the weather conditions. As one of the primary aerial aerograph, the radiosonde mainly measuring the temperature and humidity what affects the intensity of icing. Due to strong anti-electromagnetic interference, high sensitivity, light weight, small dimension and other advantages, fiber-optic ice sensor is out of question the future icing detector to develop. So a system which combines the fiber-optic ice sensor and the radiosonde is available to use in meteorologic icing detection.Firstly, this thesis introduces the method of researching on the weather conditions of icing, and illustrates the fundamental principle of a reflective fiber-optic icing sensor and a transmitted fiber-optic icing sensor. Contrast to the different of methods of weak signal detection, and based on the experiment of adopting lock-in detection, digital sampling integrator is regarded a key technique in signal processing in the system. Secondly, according to the require of detecting on the weather condition of icing, the structure of reflective icing detection device with high capture ratio and transmitted icing detection device with wide range, two fiber-optic probes including round head probe and wedge-shaped probe whose detecting pattern with single emitting fiber and double receiving fibers and another rectangle probe whose detecting pattern with single emitting fiber and signal receiving are designed. Thirdly, the signal detecting and processing section includes switching drive circuit, design of photoelectric transformation and preamplifier, the realization of digital sampling integrator and PWM signal low-pass filter. Finally, the icing experiment in the simulation of meterologic icing is designed for the purpose of the feasibility of weather icing detection with fiber-optic sensor, and a large number of basic laboratory tests give out icing characteristic analysis of fiber-optic icing detection system.The results show that the fiber-optic ice sensor is feasible in the detection of weather conditions of icing, as the same three probes which separately focus on high sensitivity, frozen ice type distinguishing and wide range provides substance to ice information fusion in the future.