Meteorological Instrumentation for the Aerosonde Autonomous Sounding Aircraft

A variety of recent technical developments, especially in lightweight equipment for navigation and communications, has created opportunity for long-range autonomous operations by aircraft of remarkably small size. Aircraft weighing less than 15 kg can now carry avionics and fuel sufficient for missions of several thousand kilometres and several days duration, at altitudes from sea level to perhaps as high as 15 km. Their payload, while small, will accommodate many applications in meteorology, and in other areas of earth and atmospheric science. Moreover their low cost should stimulate use on a wide scale. The Insitu Group began developing such aircraft in 1992. We call them aerosondes because our focus has been on measurements comparable to those made by meteorological radiosondes. Three prototypes have been built, and the components necessary for long-range autonomous missions have been demonstrated. Work is continuing on an initial operational version of the aircraft, with the objective of starting service trials in November 1995. The Marine Meteorology program of ONR, in association with the Australian Bureau of Meteorology, has sponsored this work from an early stage. Further support is being provided by the USAF Office of Scientific Research. Here we propose a vital component of the program which is not fully funded as yet: namely, development of the meteorological sensing techniques (ie those for pressure, temperature, humidity, and horizontal wind components). The Phase I work would be completed in time for November 1995 field trials. Phase II would encompass enhancement of the instrumentation set as well as extensive long-range operations. These would include tropical cyclone reconnaissance and coastal monitoring, which have been principal objectives of ONR sponsorship to date.