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 The Raytheon-Hughes-Kongsberg HAWK-AMRAAM system employs either HAWK missiles or surface-launched AMRAAM missiles shown here mounted on the Raytheon universal launcher

 

AN/MPQ Sentinel
new US army forward area air defence system

By James van der Naald.
The US Army's new battlefield air defence system centres on Raytheon Systems (formerly Hughes Aircraft Company) Stinger missile and the AN/MPQ-64 Sentinel radar system. The contract to produce six pre-production systems was awarded in February 1992 and since then the system has been upgraded from its first configuration by the addition of a state-of-the-art, commerciaI-off-the-shelf (COTS) signal processor based on Texas Instruments' C-40 technology. The updated version increases reliability and makes quick air transport to future hot spots simple. The first unit equipped FUE milestone was with the 4th Infantry Division at Fort Hood Texas in August 1997.
The Sentinel radar operates in the I/j frequency band with an antenna rotational rate of 30 revolutions per minute. The antenna presents a flat planar array surface that transmits a narrow electronically formed beam using phased array techniques. Sentinel has an integrated Ft system also, with its smaller antenna mounted on the opposite side of the rotating radar antenna.
While the antenna rotates mechanically in azimuth, the beam is directed by computer to search a surveillance sector in elevation. With rapid beam positioning, targets are tracked while surveillance continues. When a target is detected, a verification beam cluster verifies a target's validity as an aircraft track. Following verification, the target is placed into active track and reported through the data network to weapons and command and control elements. Even while the antenna rotates mechanically, multiple transmitted beams dwell on the target by back-tracking electronically as mechanical rotation proceeds so that verification of a new target and tracking of the target can be accomplished in a single rotation.
P45 Pic A.jpg (10613 bytes) To preserve the accuracy of track data received at the weapons it is transmitted simultaneously to command posts and weapons so both have near-real time targeting data. The US Army uses the enhanced position location reporting system (EPIRS) for the distribution of track data and command and control information. For the international market a system including Stinger weapons, EPLRS data radios, and battle management command and control command posts is available. In its complete configuration, system elements can locate at widely dispersed ground positions linked by radio communications. The Sentinel radar can locate at a ground position optimal for surveillance while command post shelters locate near command elements. VSHORAD-class weapons also interface by radio so they can be located at forward positions with wide spaces between them to make best use of their limited range.
Command posts allow targets to be individually paired with weapons and give the weapons control officer a range of battle-management functions including target identification, establishment of engagement rules and weapons control orders.
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The MANPADS alerting and cueing system with its AN/PAS 18 night sight is automatically linked to Sentinel's command and control for three-dimensional cueing of Stinger

The Sentinel radar's three dimensional performance fixes target tracks in azimuth, altitude and range so weapons slew to cue by means of automatic weapon interfaces. For weapons in the VSHORAD category, engagement near the weapon's maximum range is a particular advantage. With a radar range several times the range of VSHORAD weapons, firing crews are alerted to prepare for a fire mission
For Stinger in the MANPADS configuration, the Raytheon MANPADS alerting and cueing system (MACS) with its AN/PAS-18 night sight was the first automatic weapon interface developed for the Sentinel system. It uses a compass inclinometer to sense launcher attitude, and displays lead and super-elevation aiming references so the missile's seeker can lock-on with the most effective launch trajectory.In medium surface-to-air missile Systems (MSAMS), the Sentinel radar is used by the Norwegian air force in the Norwegian advanced surface-to-air missile system (NASAMS) that employs AMRAAM missiles in a surface-launched role. NASAMS evolved from the Norwegian adapted HAWK (NoAH) system that integrated the Sentinel radar with HAWK missile fire units. NoAH and NASAMS were developed by a USI Norwegian team that included Hughes and Kongsberg Cruppen.
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US Army's Sentinel forward area air defence radar shown here in its high mobility shelterless version began full scale production in 1996.

A Raytheon-Kongsberg team now offers a MSAM system called HAWK-AMRMM that draws on Sentinel and Kongsberg's command and control function for the HAWK missile, surface-launched AMRAAM or both. A launcher based on the HAWK mobility launcher can fire either HAWK or AMRAAM with minor configuration changes. This allows users with present HAWK inventories to upgrade to Sentinel and Kongsberg's fire direction system with a limited number of AMRAAM launchers, then to expand that capability in future years.
For users without HAWK in their inventories, HAWK-AMRAAM can be adopted with the AMRAAM missile only. The same AMRAAM missile is used for air-to-air and surface-to-air roles so one missile inventory suffices for both missions. Another feature of HAWK-AMRAAM is its ability to provide command and control of VSHORAD CIass weapons through the Kongsberg fire direction centre with similar capabilities to the Raytheon VSHORAD command posts

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