Precision-guided ammunition

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Laser-guided bomb BOLT-117

As precision-guided munitions ( English precision-guided munitions (PGM), smart munitions or smart bombs ) are self-steering rockets , missiles , aerial bombs and artillery shells referred that after leaving the carrier system or after firing their attitude can influence and an opposite unguided munitions larger Can achieve accuracy .

principle

Since the damage effect of explosive weapons according to the square law of distance decreases “disproportionately” with increasing distance to the target, a target can be destroyed with less or smaller ammunition with a higher accuracy. As a result, more precise ammunition causes greater effective damage and reduced accompanying damage (collateral damage).

In contrast to unguided ammunition, precision-guided weapons also have an electronic sensor for detecting the position ( GPS ) or light, infrared or radar signals , a control system, controllable tail units and an energy supply in the form of a battery .

steering

Trajectory guidance

The United States Armed Forces began as that of other countries during the First World War experiments with remote control, radio-guided light aircraft for use as a flying bomb, or as a practice target for fighter planes and anti-aircraft protection . However, with little success.

It was not until shortly before or during the Second World War that the technical principles for controllable bombs and guided missiles were largely developed.

The first weapons of this type were equipped with a program-controlled automatic steering system, similar to a simple autopilot , which was sufficient for a simple but relatively imprecise target control for area targets . Examples of this are the German guided weapons V1 and A4 / V2.

Radio-guided weapons

Steering bomb Fritz X

The first operational radio-controlled weapon was the anti-ship missile Fritz X , developed in Germany , with which the Italian battleship Roma was sunk on September 9, 1943 .

The weapon was controlled by an observer / bombardier sitting in the bomber using an early joystick . The same controls were used for the Hs 293 glide or rocket bombs ; a version with a television camera in the tip was no longer used.

Cable-operated weapons

At about the same time, attempts were made to transmit the steering signals via cables. One of the first weapons of this type used was the German X-4 air-to-air missile . The method is still common today for anti-tank guided weapons such as MILAN or HOT / TOW .

Radar-guided weapons

During the war there were attempts on the German side to target surface-to-air missiles using radar and radio remote control. Radar had already been used militarily for day and night hunting, for submarine hunting, for anti-aircraft and ship artillery, see Würzburg (radar) , Berlin (radar) and Seetakt (radar) (an early ship radar of the German Navy in World War II; the land-based version was called Freya (Radar) ).

The first use of a radar guided missile (LFK) took place in April 1945 when a United States Navy glide bomb of the type Bat (ASM-N2, SWOD MK.9) hit a Japanese destroyer after a 20 mile flight.

Optically guided weapons

Optically guided weapons (TV steering, video steering) use the visible portion of the light spectrum . At close range, missiles and targets can be observed from the starting point and the flight path can be corrected accordingly, which is not possible over long distances.

With optically guided weapons, a “bomb view” of the target is transmitted to the weapon system officer during the flight phase by camera optics mounted on the tip , who corrects the course by means of controllable tail units attached to the bomb and guides the target until the impact.

The US optical-guided weapons development program was discontinued after World War II and continued during the Korean War . Electro-optical camera bombs were then used for the first time in the 1960s. Such weapons were also increasingly used by the United States Air Force in the last years of the Vietnam War , as the political climate increasingly turned against the tolerance of so-called collateral damage from area bombing .

Although optically guided weapons do not achieve the precision of laser and satellite-guided weapons, they are still used. The United States Navy is using the AGM-62 Walleye TV-guided glide bomb in conjunction with the AAW-144 Data Link Pod on the carrier-based fighter-bomber McDonnell Douglas F / A-18 .

In addition to TV sensors in the visible light spectrum, infrared and other sensors are also used - with manual or automatic steering. An example of an infrared guided grenade is the Strix fired from mortars .

Laser guided weapons

An A-10 pilot inspects an AGM-65G

Laser-guided weapons have a laser viewfinder made of photo diodes instead of camera optics. The photodiodes only register a certain wave spectrum of monochromatic laser light , which is usually chosen outside the perceptible light spectrum . In order for the target to be recognized by the sensor, it must be marked with a laser beam from the ground or from the air until it is hit . The disadvantage of this system is the need for the bomb to have visual contact with the target during the final stages of the flight. If the visual contact is blocked by clouds or obstacles or the laser marking is obstructed, the bomb loses its target and goes off course.

Laser-guided weapons were hardly available until the development of microprocessors, but were used in the form of the BOLT-117 bomb and later the Paveway series in smaller numbers from 1968 by the US Air Force in the Vietnam War. Paveway bombs were then used in limited numbers by the British armed forces in the Falklands War in 1982 . The first major mission was during Operation Desert Storm in Kuwait in 1991 , even though 93% of all bombs in this conflict were still unguided. In 1999, laser-guided weapons such as the AGM-114 Hellfire and AGM-65E Maverick were used in large numbers in the Kosovo war , where their effectiveness suffered from the poor weather conditions on the southern Balkan peninsula .

An example of a laser-guided artillery shell is the 2K25 Krasnopol used by the Russian army and the Kitolow , which has been in testing since 2002 , which finds its target by means of a laser marking from an advanced position. The US counterpart is the 155 mm M712 Copperhead .

Satellite-guided weapons

Boeing AGM-86 cruise missile

Weapons guided by satellites determine their position using satellite navigation systems such as the US Global Positioning System (GPS-guided ammunition), the Russian GLONASS , the Chinese Beidou or the Indian Regional Navigation Satellite System , which is why their operational capability is not impaired by poor visibility or insufficient laser markings can be. However, due to the low transmission power of the navigation satellites, their signal can be impaired by sources of radio interference, so-called jammers . This is why these weapons also have an inertial navigation system that takes over flight control if the signal is lost.

The circular error probability , i.e. the radius in which the warhead hits with a probability of 50%, is 13 m in GPS systems. In comparison, inertial navigation only reaches 30 m and increases (in contrast to GPS) with increasing dropping height. The targeting accuracy of satellite-guided weapons depends both on the precision of the measuring system for determining the position and on the accuracy of the target coordinates. The latter are often based on imprecise intelligence information. In the case of immovable objects, spy satellites often provide the coordinates.

Satellite- guided cruise missiles such as the BGM-109 Tomahawk and AGM-86 Cruise Missile were used for the first time in large numbers by the US armed forces in Operation Iraqi Freedom in 2003 in order to destroy Iraqi air defense positions and communication centers in a first wave of attacks without endangering their own pilots .

Even with artillery shells ( shells ), the precision steering its way. The American Excalibur and the Italian Vulcano are equipped with GPS steering.

Terrain-contour adjustment

The terrain contour comparison ( English Ter rain Co ntour M atching , short TERCOM ) is a procedure in the navigation . With this method, cruise missiles are mainly guided into a target area today .

Inertial steering

An inertial navigation system or inertial navigation system (Engl. Inertial Navigation System ), short- INS is a 3D measurement system with acceleration sensors and gyro-stabilization . By integrating the measured accelerations, the spatial movement of the ammunition and from this the respective geographical position is continuously determined.

See also

Web links

Individual evidence

  1. ↑ Globalsecurity entry for BOLT-117
  2. ↑ Norbert Thomas: Accurate in action (Part 2). In: luftwaffe.de. March 27, 2012.