Colorado WAM separations standards targets of opportunity and flight test analysis

The Federal Aviation Administration (FAA) Surveillance and Broadcast Services (SBS) Program Office and the Colorado Department of Transportation are implementing Wide Area Multilateration (WAM) in Non-Radar Airspace (NRA) to improve air traffic services at and around routes and fixes that support operations at Hayden/Yampa Valley (HDN), Craig-Moffat (CAG), Steamboat Springs/Bob Adams Field (SBS), and Garfield County Regional - Rifle (RIL) airports. In particular, the lack of comprehensive radar surveillance at and below 10,000 ft. in these regions requires controllers to use procedural separation standards for the Instrument Flight Rules (IFR) arriving/departing aircraft. While this is a safe means of providing service, it is inefficient for current traffic and especially for expected demand growth. Wide Area Multilateration is a distributed surveillance technology that utilizes a constellation of ground stations to provide surveillance coverage within a defined region. This technology makes use of signals transmitted from Air Traffic Control Radio Beacon System (ATCRBS) (Modes A and C) and Mode S transponders, in response to interrogations. The Mode S transponders also provide the squitter message once per second. The implementation, certification, and commissioning of WAM would enable air traffic controllers to apply more efficient separation standards for aircraft operating in the affected airspaces. For this operational environment, with WAM as the surveillance technology, the FAA seeks to achieve 5 NMI lateral/longitudinal separations. This paper describes the technical results from the data modeling, controlled flight test, and targets of opportunity analysis for the WAM sensor constellations near HDN and RIL to support separation standards within the Host Computer System (HCS) automation platform environment at Denver Center (ZDV). Comparative analysis was conducted between WAM and Secondary. U.S. Government work not protected by U.S. Copyright. Surveillance Radar (SSR) to evaluate and validate WAM performance to support separation services.