NEWS | July 29, 2021

NRL Demonstrating Advanced Distributed Radar Concepts with FlexDAR

By U.S. Naval Research Laboratory, Corporate Communications

The U.S. Naval Research Laboratory (NRL) completed the installation of the Flexible Distributed Array Radar (FlexDAR) earlier this year and began demonstrations with nodes operating at the NRL Chesapeake Bay Detachment in Maryland and at the NASA Wallops Flight Facility in Virginia.

The FlexDAR concept was conceived by NRL to demonstrate new and advanced capabilities enabled by the implementation of every-element digital beamforming (EEDBF) antenna arrays combined with network coordination and precise time synchronization. EEDBF is an emerging technology which provides a huge leap in antenna capabilities that, when combined with network coordination and precise time synchronization, enables new and advanced radar capabilities. This, along with flexible digital processing, offers a number of attractive features well beyond the capabilities of conventional arrays and radar systems.

FlexDAR demonstrates dramatic performance improvements in detection range, tracking accuracy, and electronic protection when operated in a distributed configuration.  Each radar incorporates every element digital transmit and receive beamforming that enables multiple simultaneous full-gain receive beams within each radar’s field of view. Each radar operates at S-band and consists of 1,008 elements.

Both FlexDAR systems are now operational and will allow the full capability of the FlexDAR concept to be developed and demonstrated over the coming months and years. The FlexDAR system represents the state of the art in distributed radar technology.

NRL engineers and scientists led the development of the technical aspects of the FlexDAR program. Requirements for the arrays were developed by the NRL team, and Raytheon Integrated Defense Systems, now known as Raytheon Technologies, won the competition to build the two arrays. NRL personnel designed and implemented the radar signal processing and tracking algorithms, network coordination techniques, and an advanced graphical user interface, referred to as the FlexDAR Back-End (FBE).

Raytheon produced, integrated, and tested two phased-array FlexDAR Front-End (FFE) subsystems based on the NRL requirements. The FFE implements EEDBF and is integrated with the FBE using only a few high speed fiber-optic Ethernet connections and a single analog signal to provide a common clock. The FBE and FFE are built using Open Standards and form just one possible configuration of this fully software defined platform.

The NRL and Raytheon team integrated the systems and have verified many of the key capabilities of FlexDAR including low antenna side lobe levels, multiple simultaneous and independent receive beams, multiple simultaneous sub-apertures, distributed radar tracking, and data throughput.

Verification of capabilities is ongoing, and the testbed will support continued development and demonstration of advanced distributed radar concepts.

The Office of Naval Research sponsored the FlexDAR program as part of the Integrated Topside and Electromagnetic Maneuver Warfare Command and Control Innovative Naval Prototype (INP) programs.  ONR INPs develop higher risk technologies that offer potential leap-ahead capabilities, but do so ahead of formal naval requirements. 

The program was a collaboration with the NRL Radar and Information Technology Divisions and Raytheon Technologies.

About the U.S. Naval Research Laboratory 

NRL is a scientific and engineering command dedicated to research that drives innovative advances for the U.S. Navy and Marine Corps from the seafloor to space and in the information domain. NRL is located in Washington, D.C. with major field sites in Stennis Space Center, Mississippi; Key West, Florida; Monterey, California, and employs approximately 3,000 civilian scientists, engineers and support personnel.

For more information, contact NRL Corporate Communications at (202) 480-3746 or