Television guidance

There, a weapons officer or bomb aimer watches the image on a television screen and sends corrections to the missile, typically over a radio control link.

The concept was first explored by the Germans during World War II as an anti-shipping weapon that would keep the launch aircraft safely out of range of the target's anti-aircraft guns.

[1][2] The first concerted effort to build a television-guided bomb took place in Germany under the direction of Herbert Wagner at the Henschel aircraft company starting in 1940.

Not being able to see the control surfaces after launch, the operators had to wait until they could see the bomb begin to move and then use opposite inputs to stop the motion.

But when viewed through the television screen, the motion was immediately obvious and the operators had no problem making small corrections with ease.

If the launch was too far behind the target, the operator eventually ran out of control power as the missile approached, leading to a circular error probable (CEP) of 16 m (52 ft), too far to be useful.

This was addressed by training the controllers to ensure they had taken any last-minute corrections before this point, and then hold the stick in whatever position it was once the image grew to a certain size.

These were initially of low importance, as both the Army Air Force and US Navy were convinced that the Norden bombsight would offer pinpoint accuracy and eliminate the need for guided bombs.

It was not long after the first missions by the 8th Air Force in 1942 that the promise of the Norden was replaced by the reality that accuracy under 900 metres (1,000 yd) was essentially a matter of luck.

By 1944 the system was considered developed enough to attempt combat testing, and the two launch aircraft and a small number of GB-4 bombs were sent to England in June.

Attempts to use the system to produce an air-to-air missile using command guidance failed due to issues with closing speed and reaction time.

[13] By the end of the war, advances in tube miniaturization, especially as part of the development of the proximity fuse, allowed the iconoscope to be greatly reduced in size.

The system was designed to glide at an angle of about 40 degrees above the horizon and could be manoeuvred throughout the approach, to allow it to be directed onto a target within six seconds of breaking through cloud cover at 10,000 ft (3,000 m).

An even larger "Special Blue Boar" developed with a 20,000 pounds (9,100 kg) payload, intended to deliver nuclear warheads from the V-bombers at range as much as 25 nautical miles (46 km; 29 mi) when dropped from 50,000 ft (15,000 m) altitude.

Although successful, the program was cancelled in 1954 as the naval version grew too heavy to be carried by their new strike aircraft, while the V-bombers were slated to receive the much higher performance Blue Steel.

[19] In the early 1960s, Matra and Hawker Siddeley Dynamics began to collaborate on a long-range high-power anti-radar missile known as Martel.

The idea behind Martel was to allow an aircraft to attack Warsaw Pact surface-to-air missile sites while well outside their range, and it carried a warhead large enough to destroy the radar even in the case of a near miss.

The Blackburn Buccaneer had been designed specifically to counter these ships by flying at very low altitudes and dropping bombs from long distances and high speeds.

At the time there was no indigenous active radar seeker available so the decision was made to use television guidance and data link system to send the video to the launch aircraft.

Although this required the missile to fly high enough to be visible to the ship, its small size made it an elusive target for radars of that era and especially weapons.

Early use of the Bullpup demonstrated that it was too difficult to use and exposed the launch aircraft to anti-aircraft fire, precisely the same problems that led the Germans to begin TV guidance research.

This was not a true television guidance system in the classic sense, as the operator's task was to continue selecting points of high contrast which the seeker would then follow.

Walleye II was a much larger version based on a 910-kilogram (2,000 lb) bomb to improve performance against large targets like bridges, and further extended range to as much as 59 kilometres (37 mi).

The Soviet Kh-59 is a long-range land attack missile that turns on its television camera after 10 kilometres (6 mi) of travel from the launch aircraft.