Fast Temperature and True Airspeed Measurements with the Airborne Ultrasonic Anemometer–Thermometer (AUSAT)

Abstract

An airborne thermometer-anemometer with fast response is designed and built using the well-known sonic anemometer-thermometer technique. The shape of this new airborne sonic sensor, without the conventional style probes, is a cylinder with its axis colinear to the aircraft's longitudinal axis. The true airspeed and the air temperature are measured in the same volume. A previous paper described a preliminary version of this sensor and presented data of flight tests obtained on board Me te o France's Cessna 206. This new paper shows an improved sensor and the results obtained on faster aircraft such as the CNRS-INSU's Fokker 27 and the Me te o France's Merlin IV. First, the sensor and the principle of the measuring method are described, then data collected during several flights from 1996 to 1998 are presented. Although this new thermometer-anemometer is not completely calibrated, it provides mean data very close of those measured by conventional sensors but with a response time 30 times shorter.