In aviation

Aviation

Aviation is the design, development, production, operation, and use of aircraft, especially heavier-than-air aircraft. Aviation is derived from avis, the Latin word for bird.-History:...

, Precision Runway Monitor System is a high-speed, high-precision radar system developed by Raytheon

Raytheon

Raytheon Company is a major American defense contractor and industrial corporation with core manufacturing concentrations in weapons and military and commercial electronics. It was previously involved in corporate and special-mission aircraft until early 2007...

 for use in monitoring simultaneous close parallel instrument approaches

Instrument approach

For aircraft operating under instrument flight rules , an instrument approach or instrument approach procedure is a series of predetermined maneuvers for the orderly transfer of an aircraft under instrument flight conditions from the beginning of the initial approach to a landing, or to a point...

 to airports. PRM contains no moving parts and scans at a rate of once per second, allowing monitoring of approach corridors with accuracy of about one milliradian.

PRM is one type of radar system that can be used to allow simultaneous approaches on parallel runways that are spaced less than 1525 metres (5,003.3 ft) to each other. Airports at which PRM is in use in the United States

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 include Minneapolis

Minneapolis-Saint Paul International Airport

Minneapolis-Saint Paul International Airport is the largest and busiest airport in the five-state upper Midwest region of Minnesota, Iowa, South Dakota, North Dakota, and Wisconsin.-Overview:...

, St. Louis

Lambert-St. Louis International Airport

Lambert-St. Louis International Airport is a Class B international airport serving Greater St. Louis. It is located approximately northwest of downtown St. Louis in unincorporated St. Louis County between Berkeley and Bridgeton. It is the largest and busiest airport in the state with 250 daily...

, New York

John F. Kennedy International Airport

John F. Kennedy International Airport is an international airport located in the borough of Queens in New York City, about southeast of Lower Manhattan. It is the busiest international air passenger gateway to the United States, handling more international traffic than any other airport in North...

, Philadelphia

Philadelphia International Airport

Philadelphia International Airport is a major airport in Philadelphia, Pennsylvania, United States, and is the largest airport in the Delaware Valley region and in Pennsylvania...

, San Francisco

San Francisco International Airport

San Francisco International Airport is a major international airport located south of downtown San Francisco, California, United States, near the cities of Millbrae and San Bruno in unincorporated San Mateo County. It is often referred to as SFO...

, and Atlanta

Hartsfield-Jackson Atlanta International Airport

Hartsfield–Jackson Atlanta International Airport , known locally as Atlanta Airport, Hartsfield Airport, and Hartsfield–Jackson, is located seven miles south of the central business district of Atlanta, Georgia, United States...

. International installations include Sydney, Australia and Chek Lap Kok

Chek Lap Kok

Chek Lap Kok was an island in the western waters of Hong Kong. Together with the smaller Lam Chau, it was leveled and merged via land reclamation into the platform for the current Hong Kong International Airport, which opened for commercial operations in 1998...

 in Hong Kong

Hong Kong

Hong Kong is one of two Special Administrative Regions of the People's Republic of China , the other being Macau. A city-state situated on China's south coast and enclosed by the Pearl River Delta and South China Sea, it is renowned for its expansive skyline and deep natural harbour...

. However, Hong Kong has yet to make use of the system owing to bureaucratic red tape and face saving.