The ability to fly at supersonic speed without producing unsettling sonic booms would re-open a path to faster commercial aviation. In pursuit of aerodynamics that would soften the boom to a dull thud, NASA's Armstrong Flight Research Center engineers developed a ground-based schlieren imaging system that allowed them to photograph shockwaves produced by an aircraft traveling at supersonic speeds.
For a future quiet sonic boom test plane flying at a much higher altitude, a ground-based camera will be too far away to produce detailed images. To get a better look, the researchers will place a camera aboard a chase vehicle to capture shockwave images. The chase vehicle will need the ability to adapt in real time to the trajectory of the test vehicle and its shockwaves with a high degree of precision — no small feat at speeds beyond Mach 1.
To ensure that the chase plane can maintain the right position to photograph the shockwaves, an Armstrong team devised the Airborne Location Integrating Geospatial Navigation System (ALIGNS). ALIGNS will make it possible to receive and visualize information produced by the test vehicle to refresh the waypoints — latitude, longitude, altitude, and time points — of the chase vehicle in real time. ALIGNS will ensure the pilot will be able to guide the camera aircraft to the right place at the right time to capture quality shockwave images.
ALIGNS can be easily adapted to other multi-aircraft applications, such as cooperative trajectories and probing, regardless of vehicle model. It is coded in the Python® programming language for ease of editing as well as the flexibility of being able to run on many different operating systems and hardware configurations. This allows the use of microcomputers and other commercial off-the-shelf components.
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