The beginning of mass use of precision aircraft bombs began in the 1990s, when the leading powers faced the main problem of such weapons – the price. To solve this problem, they started searching for alternative systems that would reduce the price and make this type of weapon more mass-scaled. Due to this, the JDAM and its analogs have entered the global market and Ukraine.

What is JDAM?

A high-precision kit for the Мк.80 series aircraft bomb known as the JDAM (Joint Direct Attack Munition) was developed in the 1980s, and was intended as a cheaper alternative to laser-guided munition. The developers managed to reduce the cost of the product by twice as much. That ensured a scaling up of production of this type of high-precision bombs. The main feature of the high-precision kit is the addition of Mk.80 series bombs, a GPS unit, and steering control, which are used to adjust the bomb in the air. Today, the cost of such a kit varies from $21,000 thousand to $31,000, depending on the bomb’s caliber.

The feature of the kit, first of all, lies in its low price, which is lower than high-precision bombs with laser guidance of the Paveway series, the cost of which varies from $30 to $80 thousand.

It also should be noted that the bomb kit consists of reliable components that will be difficult to damage during transportation, or when installed on a bomb. The components themselves are easily mounted in a short time, and can also be dismantled.

What does it consist of?

The main components for creating precision ammunition from a modular aircraft bomb of the Мк.80 series are:

• three aerodynamically stabilizing surfaces;
• tail part with equipment;
• cover for wire protection.

The main element of the set is the tail assembly, where the main equipment is hidden, which performs the main functions in the correction and stabilization of the bomb after dropping from the aircraft. The tail part in particular includes:

• GPS antenna;
• antenna GPS cable cover;
• tail drive amplifier;
• wiring to the GPS system;
• sockets for connection;
• MIL-STD-1760 standard connector.

Steering control movement is conducted due to the drive installed at the rear of the aft unit. It receives the commands from the control system, and uses the rudders to equalize the bomb, providing flight along a given trajectory.

How does JDAM guidance occur?

To accurately hit the target, the kit uses two main methods of guidance: inertial system and GPS correction.

Inertial navigation guidance is the most important guidance system in JDAM, since it is used throughout the whole flight, and even before dropping a bomb from the aircraft. The inertial navigation system (abbreviated INS), is used to calculate the speed, and position of the aircraft and transmits correction to the main planning computer, providing the first set of information for successful discharge. The INS itself consists of an IMU 3D ring laser gyroscope and an accelerometer. The bomb constantly exchanges information with the aircraft to update the main indicators.

IMPORTANT: In case an enemy uses a powerful electronic warfare system and the aircraft’s tail GPS antenna can’t connect with the main systems, the INS can act as the main bomb guidance system (if an aircraft with an integrated interaction system is used) after the drop.

In the case of using only the inertial navigation system, the accuracy of the bomb will decrease according to the flight time. I.e., if the bomb after release uses INS for 38 seconds, its circular error probability will be 13 meters. And with an increase in flight time to 100 seconds, it will be approximately 30 meters.

Guidance using GPS is used to adjust the bomb at specified stages of flight, providing an accurate hit on the target. To make effective use of this capability, aircraft systems update data on the bomb’s onboard computer and inform it of the GPS quality in the appropriate discharge area. This data can be stored for about one week, without the need to update it.

For high-quality connection, the bomb uses a 12-channel GPS receiver, which provides the ability to connect to more satellites. It should also be noted that the bomb cannot connect to the satellite when it is placed under the wing of the aircraft. The receiver starts searching for satellites only after the bomb has been dropped.

GPS connection does not occur immediately: it needs 27 seconds after the bomb release. After establishing the connection, the computer immediately updates the INS data to provide the bomb with up-to-date information regarding its current position.

Why is the integration of a bomb with an aircraft important?

The use of JDAM-ER correctable bombs by the Ukrainian Air Force is possible due to the bomb programming at the airfield before departure. This is a working scheme that in a short space of time can allow any aircraft to use this bomb.

In fact, integration with the aircraft is very important, and provides an exchange of information between the carrier and the bomb for successful use. After activating the weapon control system, the aircraft performs an analysis of the state of the bomb to determine its technical condition and the functioning of all its systems.

When selecting a JDAM bomb in the weapons control system, a pilot must calibrate the inertial guidance system, by light maneuvers and moving the wing to the corresponding signal on the screen. At the same time, the aircraft information system begins loading other information, such as a “hard key,” to find a specific GPS satellite.

The guidance and input of coordinates during flight is an additional advantage. It provides flexibility to conduct some aerial operations where the target designation is issued directly in flight.

It should be noted that the necessary preparatory procedures for the selection of this type of ammunition by the pilot should take about 10 minutes while the aircraft conducts the appropriate operations to check and adjust the bomb.

UMPK: Russian analogue of JDAM

After the transfer to Ukraine of American JDAM-ER bombs, the Russian side began research to create its own analog, which was supposed to provide similar capabilities as the American kit. After some time of research, the Air Force of the Russian Federation began to use its own alternative kit, which, due to rapid development, and the lack of suitable bombs turned out to be rather rough, and unreliable.

First of all, as noted above, UMPK is installed on conventional aircraft bombs, which do not have special rudders for adjustment. This sometimes becomes the reason that after the drop, the kit does not cope with the load, and falls to the ground. Glonass, GPS, Beidou and Galileo are used to guide these bombs.

Despite such shortcomings, the Russians managed to create a deadly kit for outdated aircraft bombs, carry out discharges at a distance of no closer than 45 kilometers from the front line, and hit targets at a depth of up to 15 km. This range makes it difficult to intercept carriers, and in most cases allows the Russians to avoid the punishment for its actions.

Can Ukraine create its own JDAM?

Due to the cheapness and possibility of using civilian components, most countries in the world succeeded in implementing the creation of a kit for precision bomb guidance. Countries such as Turkey, France, North Korea, Pakistan, India, and others have managed to provide their air forces with such weapons. It should be noted that to realize the full potential of such kits, most countries use American modular aerial bombs of the Мк.80 family which can easily be improved both with the JDAM kit, and the laser version of LJDAM, etc.

Ukraine has several ways to create its own precision kit, which will involve the usage of Soviet-type- and American modular bombs. In the first case, the very idea of ​ ​developing a kit for Soviet aerial bombs is doubtful since they are not produced in Ukraine or other post-Soviet countries, except the Russian Federation. The reserves of these bombs are already limited, in addition, it is necessary to take into account the fact that Ukraine will soon receive American F-16 fighters. Providing such jets with such types of aviation weapons will be somewhat easier since the number of countries operating and manufacturers are quite large.

Such kits can be created in Ukraine: here many scientific and production enterprises have developments on this topic. For example, the company “ADRON” created a BAU-01КТЕ kit designed to ensure the effective hit of fixed, in particular small-sized, and protected ground targets. It is designed for use with bombs weighing 500, 250 and 100 kg.

However, the rationality of kits’ production in Ukraine is questionable. Due to the constant supply of such bombs by the United States, Ukraine can get a ready-made solution, without many years of tests, and other problems.