Passive Aircraft Avoidance through EO/IR Imaging and Reconfigured TBAD

Laser-guided adaptive optics (AO) is an essential tool for ground-based telescopes tasked with carrying out observations in support of space domain awareness (SDA) objectives. AO removes the blur imposed by the turbulent atmosphere and enables both high-resolution and high-contrast imaging. However, laser guide stars (LGS) used in support of AO present significant technical and operational challenges. Of critical importance is the issue of safety, since the lasers used to make LGS are Class IV with typical output power of tens of watts. Great care must be taken not to illuminate aircraft in navigable airspace. To protect air traffic, human spotters have in the past often been used with the FAAĺs blessing. This is a risky approach however: people are all too easily distracted or become tired, and it is also very difficult to identify aircraft at night that may not be using lights (a not uncommon occurrence for military training missions for all but the lead ship). During the day, aircraft are often difficult to see even when they can be heard. For these reasons, the FAA has recognized that automated aircraft detection systems are simply more robust and reliable than people. In this Direct to Phase II program, HartSCI will design, build, deliver, and demonstrate a comprehensive and flexible automated system for aircraft protection. The Automated Aircraft Deconfliction System (AADS) exploits several independent modalities to provide robustness and redundancy. Included in the architecture is a modified Transponder-Based Aircraft Detector (TBAD) antenna array configured for telescopes of 1-2 m diameter, as well as passive EO and thermal IR imaging. Additional input sources include E-stop and human-held kill switches, and future expansion is anticipated to allow for feeds from FAA Air Route Surveillance Radar (ARSR) and Terminal Radar Approach Control (TRACON) facilities where available. The AADS will be tested against known aircraft in the vicinity of HartSCIĺs offices in Tucson before being delivered to the government. HartSCI personnel will then be available to assist in deploying and demonstrating the system at a government observatory, and to transition it to service.