Analysis of Event-Based Camera’s Potential for In-Flight Measurement on Hypersonic Test Vehicles

Wind-tunnel testing is commonly used in hypersonic research, but the challenges of windtunnel include limited run-time and Mach number, restricted model dimensions and effects on boundary-layer transition by tunnel noise. Flight-testing offers an alternatively approach for obtaining hypersonic data at conditions close to real vehicles. Most existing flight-test diagnostic tools are based on cameras or point-sensors. The latter are compact and fastresponding, but not spatially-resolved. And while cameras provide 2D or 3D measurements, kHz-rate cameras are large, heavy (0.5-5kg) and too data-intensive (e.g. GB/s) for either continuous-recording or fast in-flight downlink. To address these challenges, we explored the use of nascent event-based (EB) camera as an alternative foundation for in-flight optical diagnostics. An EB camera employs independently event-triggered pixels to provide ~100kHz response rate in a data-sparse format, and are extremely compact in device size (~40g, ~50mm). However, the new EB paradigm requires significant redevelopment of application know-how, two aspects of which were explored in this paper: (i) experimentally characterizing the response of EB cameras to targets representative of flight-test subjects, and (ii) predicting how EB cameras’ data output rate and bandwidth-limit scale to hypersonic measurements.