Over the years technology evolutions have played a meaningful role in helping scientists better understanding weather, providing the insights needed to make better predictions. Of course, gaining a better understanding often requires conducting multiple tests.
Case in point? UAVOS Inc. and Stratodynamics Inc. have successfully performed a series of stratospheric flights with the balloon launched HiDRON, an autonomous aircraft. The mission objectives were to advance new systems for forward sensing turbulence detection onboard aircraft at near-space and commercial flight altitudes. The early June campaign was supported by the NASA Flight Opportunities Program to advance turbulence detection sensors developed by the University of Kentucky (UKY) and NASA’s Langley Research Center.
The multi-member collaboration converged at Spaceport America to combine the novel, high-altitude aerial platform with multi-hole wind probe and infrasonic microphone sensors to advance forward detection of turbulence systems.
Beyond the balloon
One of the most common methods over the years has been the use of meteorological balloons. Unfortunately, the problem with using meteorological balloons is the impossibility for balloons to “return home,” which ultimately leads to the loss of the payload.
During the campaign, the HiDRON glider was released from the balloon at an altitude of 82,000 ft. (25 km) on the first two launches, and at 98,000 ft. (30 km) on the final launch and was gliding successfully at 92,000 ft (28 km). The HiDRON was released from the balloon in zero-gravity conditions and accelerated rapidly, approaching 300 mph ground speed (480 kph) in the first 15 seconds of flight. The HiDRON then glided in a controlled flight path back toward Spaceport America’s runway for approximately 4.5 hours while recording flight and payload data.
The UAVOS designed avionics system demonstrated stable performance in extreme temperatures from -85°F (-65°C) to +95°F (+30 °C) as well as a breakthrough in autonomous control during the critical ‘pull-out phase’ following balloon release. The UAVOS avionics system serves as the brains of the HiDRON glider ensuring safe Beyond Visual Line of Sight (BVLOS) flight profiles throughout the various phases of lift-off, ascent and landing.
"The main learning is that drones controlled by UAVOS' autopilot are suitable for air meteorological measurements, with the ability to gather most of the meteorological data such as atmospheric pressure, record wind velocity, direction, magnitude and low-frequency sound waves,” Aliaksei Stratsilatau, CEO at UAVOS tells IndustryWeek.
“By using UAV for meteorological measurements, it is possible to carry expensive sensors without the risk of losing them, which can bring about real commercial efficiency to a project,” Stratsilatau says. “It’s also possible to collect weather data at different altitudes, which leads to advancing observation capabilities and making very precise measurements. In addition, a UAV does not to affect the environment since a drone and its payload are returned home.”
As part of the collaboration, the UAVOS' autopilot algorithm of flight control without an engine has been tested. “The drone was able to fly in ascending air currents extending flight time. This learning will lead to an increased number of measurements in the future,” Stratsilatau says. “In addition, the precision of the drone landing has been proven, which means a safely and successfully completed mission.”
Also, while analyzing flight recorder data it was possible to recognize air fluctuations with a frequency of 1 Hz and a very small amplitude (0.1 m/s²) at an altitude of 23 km. The high-altitude aerodynamics data is proving invaluable for processing payload data as well as for analyzing atmospheric phenomena in the stratosphere in general.
