Design Of Measuring System For Precipitation Particles In The Automatic Meteorological Station

With the development of economy and the improvement of living standards, the weather affects people’s life in many aspects. The meteorological service plays an important role in the development of society. Automatic meteorological station (AMS) has better performance due to its advantages of higher accuracy to get meteorological information, lower operating costs, easier maintenance and so on. The measurement of precipitation particle is a very important component of meteorological observation, and has been widely applied in automated weather observation, weather modification, weather radar calibration and other areas.Rain sensors are primarily used to measure liquid precipitation. However, most rain sensors cannot distinguish solid from liquid. They only can provide rainfall measurement results. Advanced sensors can identify the solid particles among liquid particles because they use optical principles. But they are too expensive to be widely used. Moreover, the optical lens of advanced sensors is easily affected by surroundings, which result in difficult calibration and high maintenance costs.A novel measurement system of precipitation particle is designed to solve the above problems effectively. The following work is included in this thesis:(1) A new type of precipitation particle sensor and a data acquisition circuit are designed. This provides a theoretical basis for the hardware design using hydrodynamic theory and the precipitation particle sensor simulation.(2) The circuit uses a STM32F107device as main controller and uses a high-precision24-bit S-A analog to digital converter to collect data.(3) A constant power control algorithm of the precipitation particle sensor is proposed, which uses a PID algorithm and a pulse width modulation method.(4) The system uses CAN bus to communicate with an AMS.