Mitigation of Collision Avoidance Radar System Interference From Unlicensed National Information Infrastructure (U-NII) Devices

Collision Avoidance (CA) radar systems are required for compliance with the Navys operational requirement for Sense And Avoid (SAA) for Unmanned Aerial Systems (UASs). The Radar Airborne Collision Avoidance System (RACAS) is designed to provide CA capabilities for both Triton and Fire Scout. RACAS total operating frequency extends from 5100 to 5900 MHz with its primary SAA frequency from 5350 to 5470 MHz. UnlicensedNational Information Infrastructure (U-NII) also operate in this frequency band as secondary users and as such are required to vacate the frequency whenever a radar is detected. There have been numerous incidences where ground based radars have been adversely impacted. This study analyzes the impact of UNIIs on RACAS, develops mitigation techiques, and shows the feasibility of those techniques.