Helicopter in-flight tracking system (HITS) for the Gulf of Mexico

Helicopters and other low-altitude air traffic over the Gulf of Mexico operate without the benefit of radar surveillance due to the location and range of existing onshore radar installations. The NASA Ames Research Center (ARC) is sponsoring deployment and testing of a prototype helicopter in-flight tracking system (HITS) in a portion of the Gulf of Mexico offshore area. Using multilateration principles, HITS determines the location and altitude of all transponder-equipped aircraft without requiring changes to current mode A, C or S transponders. In addition to multilateration, HITS provides surveillance reports for aircraft equipped for automatic dependent surveillance roadcast (ADS-B). This paper describes the HITS project - specifically, the system equipment (architecture, remote sensors, central processing site, and communications equipment) and system performance (accuracy, coverage, and reliability).