The Research And Design Of The Small Scale Ultrasonic Wind Measurement System Based On ARM

The wind speed and direction are the important elements of the marine meteorological observation. The research is aimed to provide a new efficient scheme for the ultrasonic anemometer. There is no rotating element in the physical device. The system which do not need special maintenance has advantages of small volume, low energy consumption, high stability and precision data. If the instrument is applied in practice, manpower and material resources as well as financial resources will be saved, and finally there will be obvious economic and social benefit.The goal of the paper is to develop a small scale ultrasonic wind measurement system based on ARM. The analysis and treatment of the ultrasonic transmitting signal and echo signal are the core parts of the system. In this paper, after considering some methods of measuring the wind velocity and wind direction of the sea, the STM32F103RET6 is chosen as the main chip. It is combined with the analog multiplexer switch circuit module, the filter amplifier circuit module, the voltage comparison circuit module and so on. The value of the wind velocity and wind direction are achieved by the method of the frequency measurement which is used to analyzing and processing the original measured data.The innovation of this paper includes the following aspects:1. Through analyzing the ultrasonic propagation characteristics in the air and the ultrasonic anemometers at home and abroad, the method of the frequency measurement has been proposed for the research and design of the ultrasonic anemometer based on ARM. According to the principle of ultrasonic transducer, the hardware platform of the ultrasonic anemometer based on the STM32F103RET6 is completed by the circuit analysis and the program design so that the structure will become miniaturization.2. The complexity of the hardware circuit of the ultrasonic transmitting signal and echo signal is reduced by the ultrasonic transmitting signal which is achieved by the ultrasonic transducer and ultrasonic echo signal which is filtered and amplified by the four first-order band pass filters.3. The frequency of the ultrasonic echo signal is achieved by the over-zero comparing circuit and input capture function of the STM32F103RET6 after judging whether the ultrasonic echo signal is received or not through the software sample technology.