Ground-based radars have been undergoing a technological revolution in recent years. Technologies such as electronically scanned antennae, ultra-fast powerful processors and advanced algorithms, originally developed for strategic phased-array radars and miniaturized to fit stealth fighters, are now ready for deployment with land forces.

The benefits of active, electronically scanned arrays (AESA) are common to air and naval applications, and those capabilities are as important for land applications as they are for fighter aircraft and missile defense. Equally critical is the robust, solid-state technology that eliminates all moving parts and most single-point vulnerabilities associated with radars—thus extending the radar life cycle to decades, matching the platform's service life.

One major player in AESA technology, Israel's Elta Systems, has been among the first to deploy tactical ground-based AESA radars. Elta's EL/M-2084 Multimission Radar represents a new family of systems based on a modular design, tailored for different applications. The first prototype was rushed into service with the Israel Defense Forces' artillery corps in 2008 as part of operation Cast Lead in Gaza. Another derivative of the system was battle-proven in 2011, engaging more than 100 enemy rockets as part of the Iron Dome missile defense system.

Providing essential early warning and targeting enemy firing positions, these scalable radars are proving indispensable for land force protection. However, due to their size, weight and cost, such large radars are maintained in small numbers at the theater level. Fortunately, with the scalability and modularity of AESA, the new wave of radars is becoming even smaller and lighter, and usable down to the tactical combat level.

Currently undergoing evaluation with the military, Elta's Green Rock threat detection and warning radar is designed to deploy with infantry battalions, offering force protection to forward units. This mobile, dual-band radar operates in the L or S bands and X band. It can detect threats with low radar cross section, including UAVs, gliders and hovering platforms. It is also effective in detecting rockets, artillery and mortars at ranges beyond 10 km (6 mi.). Green Rock is mounted on an all-terrain vehicle and is designed to operate as a stand-alone forward sensor, or integrate with other sensors as part of a network. A single unit stares at a forward arc covering 180 deg. in azimuth and 90 deg. in elevation.

Another type of AESA recently tested in Israel and the U.S. is the Multimission Hemispheric Radar (MHR) developed by Israel's Rada. Also based on modular architecture and utilizing common hardware, the radar is tailored for different missions by using task-specific software. The resulting system has demonstrated impressive performance on recent counter-rocket, artillery and mortar (C-RAM) tests in the U.S., as well as in active protection system (APS) tests to defend vehicles from rocket fire. Radar modules are tailored for different applications, from APS, to force protection, low-level air defense and border protection.

Each MHR module covers a sector of 90 deg. and can operate independently. Four modules can be mounted on a single assembly or distributed at four different locations and synchronized to create full-hemispheric 3-D coverage.

Active electronic scanning has also added new dimensions for ground surveillance. Ground surveillance radars are commonly used in military and homeland security, for border protection and perimeter surveillance. Traditionally, such radars employ mechanical scanning to cover as wide a sector as possible. When suspicious movement is detected, the radar tracks it or stops and stares, to further process the Doppler signal for target identification. Electronic scanning eliminates the radar movement, thus scanning the entire area while tracking multiple targets at the same time, or focusing on specific areas over others.

Utah-based SpotterRF has recently introduced two miniature ground surveillance radars. Modestly called a “radar-equipped security system,' the M80 is the world's smallest (6.8 x 8.4 in.) and lightest (3 lb.) man-portable radar. It will detect a walking person 500 meters (1,640 ft.) away, at night or in bad weather. Slightly larger, the M600C weighs only 4 lb. and can double detection range to 1,000 meters. The unit contains all elements—processor, antenna, power communications and operating system, enabling operators to control the radar by smartphone.

SpotterRF plans to launch even smaller radars, designed for use in urban environment, effective at ranges of 100 meters and below. Beyond the ground surveillance role, the M600C can also be used as a wide-area sensor, cueing electro-optical sensors and remotely operated weapon stations at potential targets. Such automatic cueing enables remote operators to identify and engage threats effectively and safely at stand-off ranges.