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Swedish Radar Reaches New Heights

September 2003
By Henry S. Kenyon

Networked sensor offers enhanced command, control and communications.

An advanced Swedish radar system capable of rapidly detecting and tracking multiple targets provides commanders with precious additional seconds in medium- and short-range air defense engagements. The radar can quickly sweep a section of sky in three dimensions and relay data to weapons platforms or to other sensors on a network.

Time is critical when defending positions against incoming aircraft and missiles. This is especially true for close-in anti-aircraft weapons such as manportable or vehicle-based missiles and guns. An important tactical advantage is created when units have the option of beginning an engagement when they wish and within their weapons’ best operational envelopes.

Developed for the Swedish military by Ericsson Microwave Systems AB, Mölndal, Sweden, the Giraffe agile multibeam (AMB) air defense search radar is the latest in a long line of Giraffe systems. However, any similarities to predecessors like the Giraffe 75 end with the name, explains Per Järbur, Ericsson Microwave Systems’ sales director for market operations. Its radar is completely different from previous versions, featuring new algorithms and equipment that put it a generation ahead of other Giraffe models. “We threw everything away except the cabin and the mast,” Järbur says.

The Giraffe AMB is a three-dimensional (3D) C-band radar with integrated command, control and communications capabilities for use in tactical air defense and surveillance systems such as gap fillers and tactical air control. It optimizes air defense reaction time and efficiency by providing early target information and coordinating firing among different weapons platforms. Giraffe AMB units can be used autonomously for point defense or as a sensor for network-centric systems. They also are equipped with a surface channel for coastal surveillance applications.

Unlike conventional 3D search radars that use elevation scan technology, the Giraffe AMB can maintain the high target detection rate of a two-dimensional system by covering the full elevation range simultaneously with multiple antenna beams. A high 3D target update rate is combined with efficient and accurate monopulse altitude coverage. The system uses one wide beam for transmission and multiple digitally shaped narrow beams for reception. By maintaining pulse density, the unit also can maintain clutter suppression in unfavorable weather conditions.

The Giraffe AMB’s triple beam radar scans an entire volume of sky in a single sweep. Other types of 3D radar take up to three seconds per revolution to make a sweep, Järbur explains. If a Giraffe is put into an air force reference network, it will take one to two seconds to update its information. It is the first system that can provide both a high data and scan rate in 3D, he maintains. The radar is designed to be highly resistant to jamming. Järbur notes that older air defense radars used disk-lobe beams that are prone to jamming.

In the mid-1980s the Swedish military approached Ericsson to develop a system with a 3D capability. The original development models used a pencil beam, but tests from 1988 to 1992 found that it was impossible to provide the data renewal rate the military required. To meet the military’s needs, the Giraffe AMB transmits in three loops and receives on 12 loops to provide accurate elevation data.

As a former air defense officer, Järbur explains that time is critical for air defense systems, especially medium- and short-range systems. For example, earlier radar systems began an engagement with a central radar conducting a box search pattern. It typically took 5 to 20 seconds to locate a target with the engagement time from detection to intercept often taking up to one minute.

Järbur claims the Giraffe AMB radar can detect incoming aircraft in one or two seconds instead of 20. This gives commanders an additional 15 seconds to make firing arrangements and puts missiles in more favorable engagement envelopes.

Individual Giraffe AMB platforms can simultaneously coordinate air defense fire from medium-range to a large number of short- and very-short-range units. Radars are available with instrumented ranges of 30, 60, 100 and 180 kilometers. Elevation coverage exceeds 70 degrees. Tracking and sensor fusion functions include group and split tracking of up to 150 objects, track correlation, jammer triangulation and full radar netting of data from other radars and command centers.

Each Giraffe AMB is a fully autonomous system featuring integrated primary and secondary radar and command, control and communications systems. The unit and its power supply are housed in a 20-foot splinter and nuclear-biological-chemical protected cabin that weighs less than 10 tons. The extendible antenna’s operating height can be selected in two positions: 9 meters or 13 meters, depending on the surrounding terrain. One soldier can operate the radar, or it can be controlled remotely as part of a network. When command functions are needed, the crew can be increased to three persons operating three identical consoles in different role settings. The Giraffe AMB can be installed on any compatible cross-country or tracked vehicle and deployed in less than 10 minutes.

The system incorporates threat and weapons evaluation systems designed to take sensor information and model target positions. Operators then use this data to determine which battery or weapon in the network is most suitable to attack the threat.

Giraffe AMBs use Swedish datalinks and can operate with other systems such as the French air force’s Link 11 system. Ericsson’s equipment has Link 16 capabilities, but at the moment, the firm does not have a customer that requires it, he says.

A datalink system allows individual Giraffe units to receive data from other sensors and to make unit assignments for air defense purposes. Järbur explains that Giraffe AMB units can operate in a passive mode while assigning firing orders and creating local air pictures.

According to Järbur, the command and control system is now in use with the Swedish military as a command, control and communications system for air defense weapons such as the Hawk missile. The ground-based version of the radar has been sold to four foreign customers and the naval version to two.