Long-Range Communications for the Aerosonde Autonomous Sounding Aircraft

In 1995, we started field trials of miniature autonomous aircraft, an aerosonde, for long-range weather reconnaissance. With a maximum weight of only 12 kg, and a wingspan of 3 m, it has about 1500 km range and 24 hours endurance. This early version leaves much room for improvement, and we expect to double range and endurance by mid-1997. Still another doubling ultimately should be feasible, to more than 7000 km range, along with a ceiling of about 16 km. Aerosondes have already made meterological-quality thermodynamic and wind measurements, and have the potential to do so on a wide-scale with total costs in the tens of dollars per flight-hour. This project concentrates on improving communications range, which is vital to realizing the aircraft's promise. At present, a supervisory station must have line-of-sight with the aircraft, and in practice this limits operating radius to about 100 km. To go further, we need over-the-horizon communications, which means preferably, though not necessarily, a satellite relay. In Phase I, we propose to study the options, select one, and design a new avionics set for use in 1997. In Phase II, we would do long-range trials, including mid-ocean soundings and hurricane reconnaissance.