Precision Guided Bombs

Guided bombs, also known as controllable bombs, are aerial bombs that can control their trajectory and guide them after being dropped. Guided bombs are made by adding guidance devices on the basis of ordinary aerial bombs, which increase the stability of the tail wing surface. Generally, there is no propulsion system or only a small power propulsion system. Although it has a short range and limited mobility, it has a simple structure and low cost. The earliest guided bombs can be said to be the origin of air-to-surface missiles.

Modern aviation guided bombs are based on free-falling common bombs (or iron bombs) and are composed of additional guidance components. The guidance component group includes a self-missile nose and a fully movable controllable tail.

Its main features are simple structure, convenient use, long range, high hit accuracy, low cost, and high cost-effectiveness. It is the largest number of air-to-ground weapons among airborne high-precision weapons in the world.

In most cases, mechanics can directly assemble a guidance system for ordinary bombs at the airport, which is also more convenient to carry. After the standard ammunition is equipped with a guided warhead, it has a very high hit accuracy and the killing efficiency has been greatly improved. Circulation calculation deviation statistics show that the hit radius of guided navigation bombs is 50% lower than that of ordinary bombs. Modern guidance systems can ensure that the circulation calculation deviation of guided navigation bombs is within 2 meters, while the data of ordinary bombs is 30-80 meters ( Determined by the performance of the aircraft weapon control system ).

However, guided missiles also have some shortcomings. Compared with aviation missiles, their flight speed is lower and they are easily intercepted by air defense artillery. The flying speed of aerial bombs is usually determined by the flying speed of the aircraft when the bomb is launched, usually 0.8 Mach , about 280 meters per second, and the speed of missiles can reach 3 times the speed of sound, about 1 km/s.

Navigational ammunition can be divided into different types according to different standards such as the type of assembled ammunition, the type of attack target, and the quality of the ammunition. According to the weight (caliber) standard of the warhead of the navigation bomb, it can be divided into: 500 lbs (about 250 kg), 1000 lbs (400-500 kg), 2000 lbs (900 kg-1 ton), etc. There are also more powerful ammunition such as GBU-28 in the United States and ???-1500 in Russia.

What needs to be pointed out is that the terminology used by Russia and the United States for making navigational aerial bombs is different, and there are also differences in understanding of this type of ammunition. The "???" in ???-1500 is the abbreviation of Russian "corrected aerial bomb". Russia usually refers to this ammunition by "corrected aerial bomb." Russian experts believe that these ammunitions are not equipped with engines and do not have their own propulsion. The function cannot be called guided munitions. US military expert opinion on this issue from its ammunition name can be seen clearly, AGM-130 in the "AGM" is the English "Air-to-Ground Missile" ( ground missiles ) acronym, GBU "GBU" in -24 is the abbreviation of English "Guided Bomb Unit" (guided bomb), whether it is a guided aerial bomb or a guided missile, it can be called guided munitions.

The navigation missile usually adopts TV optical guidance (based on optical image guidance), thermal vision guidance (guided by visible or infrared light), laser guidance (guided by the reflected beam of the target), inertial guidance, satellite guidance, etc.

The laser guidance system is mainly composed of search equipment, optical systems and electronic circuits. The laser emits light to illuminate the target, the receiver receives the reflected laser beam and determines its direction, determines the error of the bomb aiming at the target, and then issues the necessary correction instructions to the guide head. The bomb can be positioned by the head stabilizer according to the direction of the airflow. Move up, down, left, and right to adjust the angle. The missile head is protected by a fairing that is not mechanically damaged. The special fairing allows the laser beam to pass freely, but will pass through the infrared filter only to allow the "useful" wavelength of light to pass through to eliminate interference signals.

The fairing is equipped with a light-sensitive indicator disc, which is composed of 4 fan-shaped seats, fixed by the vertical line from the missile head axis, and the reflected laser beam focused by the convex lens passes through the fairing, and then falls on the indicator disc. The landing point is opposite to the target. The positions are the same. If the beam falls on the lower left, the homing head will "understand" that the target is on the upper right of the current route, and the electronic device will issue the corresponding signal instructions to the all-moving tail wing for adjustment.

The target positioning principle of the TV or thermal vision guidance system is roughly the same as that of the laser guidance system. The camera mounted on the navigation warhead captures the scene of the ground target. After the pilot locks the target image on the video display, the bomb will be dropped. The target is compared with the target scene captured by the seeker in real time to determine the direction, distance and error, and then automatically adjust to accurately hit the target. The only difference is that the processing is not the laser reflection signal, but the color tone in the form of visible light or infrared light.

Historically, early guided bombs lacked day and night combat capabilities, were difficult to attack multiple targets at the same time, and did not have autonomous guidance functions. The emergence of the first-generation satellite-guided bomb JDAM in the United States broke this dilemma. It uses GPS satellite positioning system information to revise its own inertial navigation system to ensure that it can still complete its guidance and accurately hit the target in all-weather conditions day and night. Moreover, JDAM, which uses ordinary bombs to increase its guidance kit, is extremely low cost. In actual combat, JDAM has achieved great success.

China already has satellite-guided bombs similar to JDAM, such as the Feiteng FT series bombs. If the FT-1 bomb is launched at an altitude of 5000-12000 meters and a range of 0.6-0.9 times the speed of sound, the attack distance can reach 20 kilometers, and the accuracy can be controlled within 10-30 meters according to user needs.

In the framework of the 2016 Zhuhai Airshow exhibition, Chinese defense corporations, especially the North China Corporation (NORINCO), have launched dozens of new-generation weapons, notably a cluster of bombs, of unprecedented diversity. At the 2016 Zhuhai Air Show, China's new small-diameter precision guided munitions have become one of the hot spots of the air show. These advanced guided weapons, which are lighter and smaller than traditional guided bombs, are suitable for all kinds of fighters, bombers, Pterosaur 2 UAVs, CH-5 UAVs, and even armed helicopters. For example, the J-20 fighter jet is expected to carry at least 12 small-diameter guided bombs in its internal magazine, which can attack 12 tanks and other targets in one dispatch. With the public display of 100 kg-class small-diameter satellite-guided/photoelectrically-guided bombs, it shows that China's guided bombs continue to advance in the direction of miniaturization, high-precision, and kinetic energy optimization.

Chinese military workers combined the satellite positioning correction inertial guidance system with the photoelectric terminal guidance technology, so that my country's latest small-diameter bombs have obtained a composite guidance system. The first, second, and third problems were solved by doing multiple actions. Because of the better end hit accuracy than satellite positioning correction, the bomb will explode closer to the target (as close as one meter), and there is no need to carry too many explosives. It can be from the past 250, 500 kg Level, down to 100 or even 50 kg level.

In addition to new missiles becoming the protagonist of the 2012 Zhuhai Air Show, the series of aerial bombs also fascinated the audience. The Tianlei, Tiange, Tianjian, Tiangang and other "Tian"-brand air-dispensing weapons, laser-guided bombs, rockets, and gliding extended-range satellite-guided bombs developed by China North Industries Group Corporation Harbin Jiancheng Group Corporation, all appeared on the flight for the first time exhibition.