Mini-Refraction Sonde Field Tests.

The purpose of this program is to demonstrate that it is feasible to build a small, lightweight meteorological sonde capable of measuring index of refraction Mini-Refraction Sonde, which can be launched with a 30-gram Pibal balloon. This minisonde uses a rod thermistor for temperature and a carbon hygristor for humidity measurement. For pressure measurement, a Honeywell silicon diaphragm barometer was used. This sensor uses a silicon diaphragm on an evacuated chamber with strain-sensitive resistor sensing. The sensors are electronically time-commutated on a 400-millisecond cycle. A lightweight telemetry transmitter provides 12 watt at 400 megahertz. Power is from a lithium battery. Laboratory measurements demonstrate an rms accuracy of 0.5 C temperature and 0.8 millibar pressure. Flight tests show good operation and good agreement with radar and Rawinsonde measurements. Author