Slew-to-Cue Electro-Optical and Infrared Sensor Network for small UAS Detection, Tracking and Identification

Abstract

Embry Riddle Aeronautical University Prescott and University of Colorado Boulder have designed and prototyped a small UAS (Unmanned Aerial System) detection, tracking, classification, and identification system for UTM (UAS Traffic Management) compliance verification and counter-UAS security for non-compliant UAS. The system design, known as Drone Net, which continues to be developed and improved, is a network of sensors designed to cover a square kilometer area used instead of or in addition to RADAR (Radio Detection and Ranging). System tests completed previously have shown feasibility for lower-cost UTM and counter-UAS or enhanced classification and identification features compared to RADAR alone. The partially demonstrated and hypothesized advantages are based on not just track data, but additionally target characteristic shape, texture, and spectral data from EO/IR (Electro-Optical Infrared) sensing that can be used with MV/ML (Machine Vision and Machine Learning). For EO/IR to provide effective data to MV/ML, a narrow-field camera system must track small UAS to provide an effective small cross-section image (less than 1 meter) along with track. To address this challenge, we have coordinated the use of an All-sky camera system with a hemispherical wide field of view and six cameras with resolution of 2 million pixels each (12 million total) for coarse detection of a potential target with azimuth and elevation estimation. The estimated azimuth and elevation in turn provide a cue for slew of the narrow-field EO/IR for re-detection of the same target and tracking with much higher optical zoom at similar or better resolution. This provides a sufficiently large target pixel neighborhood of at least nine or more pixels within an operating range similar to RADAR, which has been purpose-built for small UAS detection at similar kilometer ranges. Further, the paper provides an initial evaluation for the potential to reduce false alarm cues generated by the All-sky camera based upon supplementary acoustic cues as well as future work concepts for visual and acoustic data fusion. In this paper, we present experimental results to establish feasibility of the All-sky camera system to narrow the size of EO/IR re-detection search space with and without acoustic data fusion for slew-to-cue message generation. The All-sky allows for narrowed search space re-detection and tracking with a high optical gain EO/IR instrument used as an alternative or in addition to RADAR based upon site needs, costs, and constraints.