A counter-battery radar (alternatively Weapon Tracking Radar or Target Acquisition Radar) is a mobile radar system that detects artillery projectiles fired by one or more guns, howitzers, mortars or rocket launchers and, from their trajectories, locates the position on the ground of the weapon that fired it. More advanced systems can electronically send aiming instructions to friendly artillery for firing at hostile targets with counter-battery fire.〔 Some radars like the AN/TPQ-37 or the COBRA 〔(【引用サイトリンク】 title=EURO-ART COBRA Counter Battery Radar )〕 can calculate where hostile projectiles will land. Modern counter-battery radar can locate hostile batteries up to about 50 km away depending on the radar's capabilities and the terrain and weather. A counter-battery radar is attached to an artillery battery or their support group.
If the radar is fast and has good communications, then it may be possible to provide some warning to troops targeted by the incoming projectiles. However, many projectiles have a time of flight under a minute, which makes it difficult to give warnings without a highly automated communication system, unless the target is in the vicinity of the radar. Some counter-battery radars can also be used to track the fire of friendly artillery and calculate corrections to adjust its fire onto a particular place, but this is usually a secondary mission objective.〔
Radar is the most recently developed means of locating hostile artillery. The emergence of indirect fire in World War I saw the development of sound ranging, flash spotting and air reconnaissance, both visual and photographic. Radars, like sound ranging and flash spotting, require hostile guns, etc., to fire before they can be located.
== History ==
The first radars were developed for anti-aircraft purposes just before World War II. These were soon followed by fire control radars for ships and coastal artillery batteries. The latter could observe the splashes of water from missing shots, enabling corrections to be plotted. Generally the shells could not be seen directly, as they were too small and rounded to make a strong return, and traveled too quickly for the mechanical antennas of the era to follow.
Radar operators in light anti-aircraft batteries close to the front line found they were able to track mortar bombs. This was likely helped by the fins of the bomb producing a partial corner cube that strongly reflected the signal. These accidental intercepts led to their dedicated use in this role, with special secondary instruments if necessary, and development of radars designed for mortar locating. Dedicated mortar-locating radars were common starting in the 1960s and were used until around 2000.
Locating mortars was relatively easy because their trajectory was sufficiently close to parabolic that the simple mathematics of parabolas could be used with analogue computers. Better radars were also able to detect howitzers when firing in high angle (elevation greater than 45 degrees), although such use was quite rare. Low angle trajectories normally used by guns, howitzers and rockets were more difficult. By the early 1970s radar systems capable of locating guns appeared possible, and many European members of NATO embarked on the joint Project Zenda. This was short-lived for unclear reasons, but the US embarked on Firefinder program and Hughes developed the necessary algorithms, although it took two or three years of difficult work.
The next step forward was European when in 1986 France, Germany and UK agreed the 'List of Military Requirements' for a new counter-battery radar. The distinguishing feature was that instead of just locating individual guns, etc., the radar was able to locate many simultaneously and group them into batteries with a centre point, dimensions and attitude of the long axis of the battery. This radar eventually reached service as Euro-ART's COunter Battery RAdar (COBRA) AESA system.〔 29 COBRA systems were produced and delivered in a roll-out which was completed in Aug. 2007 (12 to Germany – out of which two were re-sold to Turkey, 10 to France and 7 to the UK).〔(【引用サイトリンク】title=COunter Battery RAdar )〕 Three additional systems were ordered in Feb. 2009 by the United Arab Emirates Armed Forces.〔(【引用サイトリンク】title=1st export success for COBRA radar in Gulf Region )〕 Simultaneous with the development of COBRA, Norway and Sweden developed a smaller, more mobile counter-battery radar known as ARTHUR. It was taken into service in 1999 and is today used by 7 NATO countries and The Republic Of South Korea. New versions of ARTHUR have twice the accuracy of the original.
Operations in Iraq and Afghanistan led to a new need for a small counter-mortar radar for use in forward operating bases, providing 360 degree coverage and requiring a minimal crew. In another back to the future step it has also proved possible to add counter-battery software to battlefield airspace surveillance radars.
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』