Inexpensive multichannel digital data acquisition system for a meteorological radiosonde

Meteorological radiosondes are launched routinely to obtain lower troposphere soundings of temperature, relative humidity, pressure, and wind parameters. The ability to carry extra sensors considerably extends the usefulness and cost-effectiveness of each sounding, permitting research into other properties of the lower atmosphere such as ozone, radioactivity, and electric field. An inexpensive four-channel digital data acquisition system is described which fits within the Vaisala RS80-15L radiosonde, for integration with other sensors. Using a 12-bit analog to digital conversion, a microcontroller formats the voltage measurements obtained for serial transmission over the radiosonde's UHF radio link at 300 baud. Maximum sampling rate on one channel is 10 Hz, which is reduced if multiple channels are sampled. The standard meteorological data telemetry is unaffected. During an entire flight in which the equipment experienced atmospheric temperatures from 4 degreesC to -55 degreesC, the absolute error on a 5 V fsd range was less than 15 mV. (C) 2005 American Institute of Physics.