Research On Optical Fiber Liquid Level Sensor

The accuracy and reliability of the aircraft fuel system measurement have an important impact on its safe use. The aircraft fuel measurement technology research and development in our country lags behind the foreign country. The fuel measurement technology is still relatively backward. As a result, it's very necessary to research a high sensitive, noise-proof level detective technique—the fiber optic level detection. Researchers all around the world have developed level detectors based on various kinds of theories with enthusiasm. Due to light weight, high temperature resistance, anti-electromagnetic interference, corrosion-resistant and other advantages, fiber-optic level sensor has been a new high-performance icing detector.This thesis introduces the principles of fiber-optic level sensor. Based on parameters of optical fiber, the configuration of the sensor is designed and its feasibility is analyzed . Light-emitting diodes and transistors are chose separately as light sources and photoelectric sensors. On the ground of elementary modem principle, a signal measurement system for fiber-optic level sensor is proposed, including the light source drive and modulation, weak signal amplification, digital processing, and so on. The signal processing circuit design the level experiments are introduced. In order to collect the weak signal from the photo detector, a low-noise preamplifier and a corrective detection circuit consisting of a synchronous integrator and a correlator which is in charge of processing corrective calculation of signals collected by photo detector are designed. According to environmental conditions for the laboratory, the author and his team design a platform for level experiments, In preliminary experiment , we received a Level - voltage characteristic curves. This thesis proved the feasibility of the sensor, through theoretical analysis and experimental methods. Meanwhile, the standard detailed analysis of various test characteristics of the sensor, the sensor provides a number of improvements in testing, the data support.The results show that the method of fiber-optic icing detection is feasible under general condition. It's extremely worthy to study it in-depth for its extensive application prospect . In future work, we will focus on the direction of improving the structure of the sensor and the performance of the signal processing circuit.