Next stage of NASA's UAV safety research: Avionics-driven detect and avoid
XPONENTIAL 2018--DENVER. Avionics company Sagetech Corporation reports that it is set to provide its MXS transponder to NASA as the government agency conducts detect-and-avoid (DAA) research in the area of unmanned aerial vehicles (UAVs).
Sagetech's transponder with integral ADS-B [Automatic Dependent Surveillance–Broadcast] -- which transmits GPS position data to other aircraft nearby for use by operators and aircraft control algorithms to maintain safe separation distances -- enables NASA's system to electronically "see" nearby aircraft and maneuver to avoid them. According to materials from Sagetech, NASA will use its equipment as it undertakes an upcoming project phase that extends its DAA research to smaller UAVs, conducting flight tests with its medium-class (group 3) SIERRA-B (Sensor Integrated Environmental Remote Research Aircraft).
Small UAVs are difficult to see, making visual detection unreliable and leading to problems with primary radars, which struggle to detect reflected energy from the small radar cross-section of these tiny craft. Transponders and associated equipment, say Sagetech officials, can overcome these obstacles by enabling UAVs to "squawk" replies to secondary radar interrogation; ADS-B equipage goes a step further by periodically "squittering" position and other aircraft data automatically. Air-traffic controllers use the information garnered by transponders and ADS-B to maintain safe separation between these aircraft.