Design And Implementation Of Ultrasonic Typhoon Velocimeter

Wind speed is an important parameter of meteorological monitoring.It is very important weather data in shipping,agricultural production and transportation^[1].Wind anemometer is an indispensable and important instrument for modern weather forecast.By real-time and accurate detection of wind speed in the atmosphere,people can more accurately predict future weather,thus guiding people's labor and production.It is of great practical significance to study the high accuracy anemometer which can monitor the network in real time^[1-2].In this paper,based on ultrasonic time difference method,we study the design of hardware circuit and software of anemometer.The first chapter is the introduction of this paper.We discuss the research background of anemometer,the research status of anemometer at home and abroad in recent years,the significance of research work and the content arrangement of this paper.In the second chapter,firstly,the working principle of the ultrasonic anemometer based on time difference method is expounded theoretically.The wind speed is superposed by the wind speed and the ultrasonic wave vector,and the wind speed is decomposed in the longitudinal direction and the transverse direction.The whole wind speed can be calculated by the time difference between the downwind and the upwind at different times^[3-5].Due to the attenuation of ultrasonic wave propagation in medium and the different transmission distance,different requirements for working frequency and voltage are required.The technical specifications of the ultrasonic wind speed tester are comprehensively demonstrated,including the azimuth parameters of the effective wave line,error analysis,probe inclination,probe parameters and the geometry of the reflector bracket.Parameters and so on.Finally,we discuss in detail the effect of vertical wind distribution on wind speed measurement.In the third chapter,we design the anemometer from the aspect of hardware circuit,elaborate the overall design scheme,and then elaborate the specific design of hardware circuit,including conversion circuit module,transmission circuit module,signal acquisition circuit module,digital processing control module,serial communication module,environmental parameter detection sensor.Modular.By synthesizing these modules,we give the hardware structure of the whole system:using FAN3100 to drive FETs,the transmitting power of the whole transmitting circuit reaches 1.01W;the receiving circuit consists of two-stage amplifier and one-stage filter comparator,in which the first stage amplifier circuit is a 14-fold amplifier common-emitter stage amplifier circuit and the second stage amplifier circuit.The filter circuit constructed by LC uses OPA365 to achieve 82 times amplification,the last one is a comparator to realize signal acquisition,PIC is used as the main control circuit,RS232 is used as communication protocol,and MAX232 produced by American Credit Corporation is used for level conversion.AM2321 is used as the humidity sensor designed.The pressure sensor BMP180 produced by BOSCH is used.The fourth chapter discusses the software design of ultrasonic anemometer.We focus on the calculation subroutine of wind speed measurement,including control subroutine,wind speed and direction calculation subroutine,wind speed and direction calibration and compensation,etc.Then the temperature and humidity monitoring subroutine and the air pressure detection subroutine are discussed.In the procedure of calibration and compensation,there are zero wind speed calibration and standard wind speed calibration in the calibration of anemometer,which should be compensated according to the calibration value.The fifth chapter is the experimental test and summary.It mainly tests the functions of the whole system,including the wind speed and direction test,temperature and humidity test and air pressure test.When the wind speed is between 0 and 40 m/s,our anemometer can be measured accurately.Compared with foreign anemometers,the error is less than 1%.The wind direction measurement data show that the error is less than 1 degree.From the results of the experimental verification,the whole equipment design meets the requirements in advance.The sixth chapter is our prospect for wind speed tester.