https://denver.cbslocal.com/2018/08/31/unmanned-airport-control-tower-colorado/https://www.codot.gov/programs/remote-tower/programs/remote-tower"The Colorado Remote Tower Project will adapt the same satellite-based technology developed for the Colorado Mountain Radar Project in 2005. This Colorado Mountain Radar Project helped solve issues associated with radar coverage of aircraft operating in and out of Colorado's busy ski country airports. The result of this endeavor successfully implemented Wide Area Multilateration (WAM) technology, giving air traffic controllers the ability to "see" aircraft throughout the entire aircraft arrival and departure sequence at Colorado's major ski destination airports despite the lack of traditional radar coverage."
