ASARS

ASARS. The Advanced Synthetic Aperture Radar System is a high-resolution, all-weather imaging radar developed for the United States Air Force. Primarily deployed on the Lockheed U-2 and later the Northrop Grumman RQ-4 Global Hawk, it provides critical intelligence, surveillance, and reconnaissance data. The system represents a key evolution in standoff surveillance technology, enabling detailed ground mapping and target detection from long ranges.

Overview

The system was conceived to provide the United States Air Force with a superior, all-weather imaging capability beyond the limitations of optical systems. It operates as a synthetic-aperture radar, creating high-resolution two-dimensional imagery by processing radar returns over a distance to simulate a large antenna. This technology allows platforms like the Lockheed U-2 to conduct wide-area surveillance and spot moving targets from significant standoff distances, contributing to national technical means of verification and supporting operations for commands like United States Strategic Command and United States Central Command. Its data is integral to the Distributed Common Ground System, where imagery analysts process and disseminate intelligence to tactical units.

Development and Deployment

Development began in the 1970s by Goodyear Aerospace to create a next-generation radar for the Lockheed U-2, succeeding earlier systems like the AN/APQ-102. The program aimed to enhance the capabilities of the Strategic Air Command during the Cold War. Following the acquisition of the division by Loral Corporation and later Lockheed Martin, the system underwent significant upgrades. Full operational capability was achieved in the 1980s, with the sensor becoming a cornerstone of the U-2S fleet. In the 2000s, a new version was developed for the Northrop Grumman RQ-4 Global Hawk under the ASARS-2 program, managed by the Reconnaissance Systems Program Office at Wright-Patterson Air Force Base.

Technical Specifications

The radar operates in the X-band frequency, utilizing a phased array antenna for electronic beam steering. It employs advanced modes including spotlight SAR for very high-resolution images of small areas and strip map SAR for broad area coverage. A key feature is its Ground Moving Target Indicator capability, which detects and tracks vehicles. The system's resolution allows it to distinguish objects as small as individual vehicles from over 100 miles away. Data is downlinked in near-real-time via satellite communications or line-of-sight datalinks to ground stations like those in the Distributed Common Ground System. The processor uses sophisticated algorithms for coherent change detection.

Operational History

The system has been deployed in virtually every major United States contingency operation since the 1990s. It provided critical imagery during the Gulf War, monitoring Republican Guard movements and Scud missile launchers. During the Kosovo War, it supported NATO bombing campaigns by identifying Serbian forces. In the War in Afghanistan and the Iraq War, it was used extensively for persistent surveillance, tracking insurgent networks and supporting counter-IED efforts. Missions have also included support for Operation Odyssey Dawn in Libya and continuous monitoring of areas like the Korean Demilitarized Zone and the South China Sea.

Variants and Upgrades

The primary variants are the original system for the Lockheed U-2 and the newer ASARS-2 for the Northrop Grumman RQ-4 Global Hawk. The ASARS-2 features a larger antenna and improved processing for greater range and fidelity. A significant upgrade program, the ASARS-2 Increment 1, enhanced the Global Hawk's capability with wider area search modes. Other improvements over time have included the integration of modern graphics processing unit technology for faster image formation and compatibility with the Multi-Platform Radar Technology Insertion Program architecture. These evolutions ensure interoperability with other systems like the AN/ZPY-2 radar on the MQ-1C Gray Eagle.

Category:United States military radars Category:Aerial reconnaissance Category:Synthetic-aperture radar