Packaging And Tseting Of Radiosonde Temperature Sensor

For a long time, people are making unremitting efforts for developing devices to detect the meteorological parameters. So far, the radiosonde has become one of the most important meteorological observation equipments. The radiosonde rises into an altitude of 10 km,30 km or even higher. In the upper atmosphere, humidity may range from 0% RH (relative humidity) to 100% RH, the pressure may range from 1080 hPa (hundred Pa)to 10 hPa or even lower and the temperature may range from 40 ℃ to-90 ℃ or even lower. Radiosonde technology abroad has been very mature, while the domestic technology is relatively backward. It’s necessary to develop the radiosonde with independent intellectual property rights, because imported radiosondes are expensive and domestic meteorological monitoring needs lots of superior radiosonde. In this paper, radiosonde temperature sensor and its package were studied. The temperature measurement problem caused by severe environment in high altitude was solved and relevant testing ciucuit was designed.The main work of this paper includes the following parts.The thin-film platinum sensor shaped as a winding was designed which reduced the chip area and short the thermal response time. The chip was fabricated by semiconductor fabrication process. The thin-film platinum sensor has advantages of good temperature linearity, short thermal response, repeatability, simple fabrication process and so on.This paper focuses on the package of radiosonde temperature sensor. The chip package on PCB was completed by traditional circuit package technology which realized mechanical protection and electrical connection. While the sensor detects meteorological parameters in high altitude, it will face a significant temperature measurement error caused by solar radiation. Anti-radiation coating was adopted to weaken the effect of solar radiation absorption. According to measurements, lots of metals own strong anti-radiation ability naturally. To meet wide anti-radiation band, high reflectivity, practicability, aluminum metal was chose as the anti-radiation material at last and revelant fabrication process was studied. The anti-radiation coatings included magnetron sputtering aluminum and dipping aluminum pulp. With magnetron sputtering aluminum, appropriate parameters of sputtering were setted in order to make the aluminum film reflectivity reach the highest. The reflection effect of sputtered aluminum film in the experiment was good. It aimed to achieve aluminum pulp with high reflectivity. Adopted fabrication materials of aluminum pulp included aluminum powder, mineral spirits and varnish. According to measurements, when the material mass ratio was set to 1:3:2, the aluminum film could achieve the highest reflectivity. Compared with the former, the reflection effect of aluminum pulp was reduced, but it has advantages of low production cost, mass production. These two methods have both advantages and disadvantages.A testing system was designed for the radiosonde temperature sensor. On the hardware, AD and DA were used to realize the excitation and output of sensor. C51 microcontroller was configured to realize the information collection, data processing and communication. On the software, C language was used to realize the signal processing, data calibration, data transmission and other functions. The performances of temperature sensor were evaluated by testing. Measurement errors of radiosonde temperature sensor are controlled within±0.3℃. Thermal response time is less than Is. The long-term repeatability and reliability of the sensors were good. Anti-radiation coating can eliminate the most of the solar radiation effect so that the measurement precision is increased greatly.