Miniature Air Launched Rawinsonde and Dropsonde (MALRD)

ABSTRACT: We describe miniature, highly rugged environmental dropsonde technology capable of four dimensional in-situ atmospheric pressure, temperature, relative humidity and Global Positioning System (GPS) wind speed/direction real time measurements. A primary goal is to provide accuracy while simultaneously withstanding the severe launch shock environment of ALE-47 Electronics Countermeasure Dispensers (ECD); past SBIR-funded R & D efforts using ECD deployment destroyed thermistors due to high initial acceleration. Our design will be capable of long periods of dormancy, yet will obtain a rapid GPS 3D lock immediately after launch, and we will use standard UHF ground support receiving equipment. To alleviate issues of thermodynamic cooling of the thermistor by rain, we plan to provide two independent methods to measure air temperature. First, a unique mechanical support will protect the fragile precision air temperature thermistor during the 100+ G launch initiation. Next, we will design an optical limb pointing infrared sensor that uses atmospheric infrared radiance arising from water vapor (humidity) in spectral absorption bands. The latter technique will provide a reliable surrogate for air temperature even when the thermistor is wetted by precipitation and experiences evaporative cooling errors. This effort includes not only hardware/firmware prototype development but also successive flight tests conducted at DoD. BENEFIT: The initial benefit is to provide real time PTU+winds data to DoD flight performance evaluation of new and existing air platforms. Numerical Weather Prediction (NWP) models run by AF and Navy weather agencies (MM5 and COAMPS) will each benefit from leveraging sounding data collected by"flights of convenience"; the thousands of ALE-47-equipped aircraft ferrying personnel and materiel to remote continents will profile the upper air in remote regions, providing data to initialize NWP models in data sparse regions such as the eastern Pacific. Next, the hurricane communities, particularly the USAF"s 53rd will benefit from additional soundings via the C-130Js they fly into active hurricanes, by removing the need for a manual dropsonde operator. DoD squadrons tasked with precision air drops as well as new P8 high altitude ASW aircraft requires dropsondes to obtain wind that enable precision emplacement of assets such as expensive sonobuoy assets. Finally, scientific research on our earth"s changing climate will benefit from increased frequency, accurate 4D atmospheric measurements.