ASR-9

ASR-9
Name	ASR-9
Caption	Airport surveillance radar system
Country	United States
Manufacturer	Raytheon
Introduced	1990s
Type	Airport surveillance radar

ASR-9 The ASR-9 is an airport surveillance radar system developed for terminal air traffic control, combining primary radar detection with secondary surveillance features. It was fielded to replace older systems at major Federal Aviation Administration facilities and integrates with national systems used by Department of Transportation and allied civil aviation authorities. The system interfaces with equipment standards from International Civil Aviation Organization procedures and participates in programs coordinated with National Airspace System stakeholders including Air Traffic Control System Command Center, National Transportation Safety Board, and regional Federal Aviation Administration Regional Offices.

History

The program evolved from radar development efforts by Raytheon, driven by requirements from the Federal Aviation Administration and influenced by research at MIT Lincoln Laboratory and Massachusetts Institute of Technology. Initial concepts trace back to postwar radar advances epitomized by projects at Bell Labs, Hughes Aircraft Company, and early systems used in World War II air defense like the Chain Home network. Funding and specifications were shaped by policy decisions in the United States Congress and coordination with National Aeronautics and Space Administration studies on terminal area surveillance. Fielding ramped up during the 1980s and 1990s with deployment at hubs such as Hartsfield–Jackson Atlanta International Airport, Chicago O'Hare International Airport, and Los Angeles International Airport under modernization initiatives that paralleled upgrades to En Route Automation Modernization and Terminal Automation Modernization and Replacement programs. Program milestones were reported in hearings before the House Committee on Transportation and Infrastructure and the Senate Committee on Commerce, Science, and Transportation.

Design and Technical Specifications

The design uses an S-band primary radar transmitter and a separate secondary surveillance radar interrogator tied to the Mode S and Mode A/C transponder ecosystem used by civil aviation authorities. Key components were produced by Raytheon Integrated Defense Systems facilities and influenced by sensor concepts from General Electric and earlier work at Westinghouse Electric Corporation. The antenna is a rotating parabolic reflector similar in concept to arrays from Marconi Company and manufacturing techniques aligning with standards from Underwriters Laboratories. Electronics include a pulse-compression waveform, coherent Doppler processing inspired by research at Lincoln Laboratory, and signal processing modules compatible with Common ARINC Standards used across Boeing and Airbus avionics suites. The system supports data outputs in formats understood by terminal equipment from Sperry Corporation and integrates with display consoles from Honeywell.

Radar Performance and Capabilities

Operational range and resolution are governed by transmitter power, pulse repetition frequency, and antenna gain, with clutter rejection achieved through Moving Target Detection algorithms originating in academic work at Stanford University and University of Illinois Urbana-Champaign. The ASR-9 provides separate primary and secondary tracks enabling controllers at Air Traffic Control Towers and Terminal Radar Approach Control facilities to manage arrivals and departures. Weather detection capability, influenced by dual-polarization research at NOAA and National Severe Storms Laboratory, aids situational awareness alongside data from Weather Surveillance Radar systems. The radar’s capability set parallels advances made in systems used by Royal Air Force and Deutsche Flugsicherung installations, and interoperability has been demonstrated with avionics suites certified under Federal Aviation Regulations managed by the Federal Aviation Administration.

Operational Use and Deployment

Deployed at major airports and terminal radar facilities across the United States, the system supports traffic flows at international hubs such as John F. Kennedy International Airport, Dallas/Fort Worth International Airport, and San Francisco International Airport. Integration with Terminal Radar Approach Control centers ensured compatibility with procedures defined by International Civil Aviation Organization annexes, and coordination with Airlines for America members shaped operational procedures. Maintenance and logistic support were overseen by FAA Technical Operations personnel and contractor teams from Raytheon, with training programs involving institutions like Embry-Riddle Aeronautical University and Florida Institute of Technology.

Upgrades and Modernization

Upgrades over time incorporated digital signal processors, solid-state components, and software from contractors including Raytheon Technologies and subcontractors with roots in General Dynamics and Lockheed Martin. Modernization efforts aligned with national initiatives such as NextGen (United States) and sought interoperability with Automatic Dependent Surveillance–Broadcast networks and En Route Automation Modernization. Programs were subject to oversight by entities including the Government Accountability Office and informed by recommendations from the National Research Council and Department of Homeland Security on resilience and cyber protection.

Incidents and Limitations

Operational limitations have included vulnerability to ground clutter, anomalous propagation phenomena studied at National Weather Service labs, and maintenance challenges reported in audits by the Office of Inspector General (Department of Transportation). Incidents involving degraded performance prompted investigations involving National Transportation Safety Board and operational changes coordinated with regional Federal Aviation Administration offices and carrier operators like Delta Air Lines and United Airlines. Constraints in capacity at peak traffic have driven transitions to newer surveillance paradigms supported by agencies including Federal Aviation Administration and international partners such as Eurocontrol.

Category:Airport radars