Air Defense: Saudis Under Heavy Attack


May 9, 2021: Saudi Arabia has a growing problem with Iranian UAVs (Unmanned Aerial Vehicles) used as cruise missiles. For several years Iran has been smuggling in UAV components to northern Yemen where Shia rebels have been trying to take over the entire country since 2014. That offensive was thwarted in 2015 by the intervention of an Arab Coalition that halted and pushed back the rebels. Unfortunately for the Saudis the home province of the Shia rebels is in northwest Yemen along the Saudi border. That border is 1,800 kilometers long although only about a hundred kilometers is controlled by the Shia rebels. Even before the civil war the Saudis suffered cross-border raids by the Yemeni Shia. Those attacks increased after 2015, with the addition of Iranian rockets and missiles. By 2017s Iranian UAVs and cruise missiles were used against Saudi economic and military targets farther from the border. The Saudis were prepared for the ballistic missiles and long-range rockets and used their Patriot AMD (anti-missile defense) systems to stop the rockets and missiles headed for a populated area or an economic or military target. The Iranian UAVs and small cruise missiles were harder to detect and shoot down. The Saudis adopted older Israeli tactics against the UAVs, which were carrying explosives on a one-way mission using GPS to guide them along a programmed course to a specific target. These improvised cruise missiles were smaller, slower and flying lower than the original American cruise missiles that used a small jet engine and, before GPS became available in the 1990s, less accurate but effective guidance systems. The Iranian UAV/cruise missiles cost a tenth of what conventional cruise missile do and are easier to smuggle into Yemen and assemble locally for a single one-way mission. These UAVs were more prone to failure and some were found on both sides of the border after they crashed. But most of them worked and the Saudis turned to their American advisors for ideas. Radars that could detect the low/slow UAVs were easier and cheaper to obtain that methods for destroying them. The Saudis have apparently been using air-to-air missiles fired by their F-15 jet fighters. This was what the Israelis used early on. There is video circulating showing a Saudi F-15 zooming past after a missile has destroyed a UAV. The missile was apparently a radar-guided AMRAMM. These cost a million dollars each and the Israelis quickly discovered that their jets could use cheaper (less than half the cost of AMRAAM) heat seeking missiles as well as autocannon fire. Using the automatic cannon carried on modern jets meant getting close (a few kilometers) to the target and risking most of the 20mm explosive shells (than don’t hit the target) injuring someone on the ground. Modern fire control systems make the use of aircraft cannon practical for situations, as long as you are firing in the direction of enemy territory.

There are other cheaper and safer, for civilians on the ground, systems available but all these have some limitations. For one thing, the most effective and battle tested systems are Israeli. While Saudi Arabia has improved its relations with Israel, the UAE (United Arab Emirates) and other Arab states have established diplomatic relations. Saudis are reluctant to purchase and use Israeli military systems. In reality the Saudis already used Israeli military technology because many American air-defense and weapons systems were developed jointly between the U.S. and Israel. That’s easier to conceal than importing air defense systems only Israel produces. Another problem the Saudis have is the long borders and coast lines they need to defend. Based on previous Iranian operations, the pre-programmed UAVs can be sent around an AUD defended stretch of border or even out into the Red Sea to attack Saudi targets from the sea or an unexpected direction. The Israelis have already handled this problem but the Saudis may be reluctant to adopt such obviously Israeli techniques. The Israeli firm Rafael developed the Iron Dome system in 2005. This system could effectively and economically destroy rockets and mortar or artillery shells. By 2017 Iron Dome was able to detect and shoot down small UAVs.

Drone Dome is a lot cheaper ($3.4 million per system) because it does not use $90,000 Tamir guided missiles to intercept rockets or shells headed for residential areas or military targets. Drone Dome uses a radar that can detect most small UAVs at ranges of up to 30 kilometers at altitudes of 10 meters (30 feet) to 10,000 meters. The smallest UAVs can be detected 3.500 meters away and jammed. Drone Dome has an optional laser gun that can be aimed by Drone Dome to destroy the drone at ranges up to 2,000 meters. In a combat zone, you can also employ machine-guns or snipers to bring down the drone.

Drone Dome is not a radical development but part of a trend. Since 2010 Israeli firms have developed a growing number of AUD systems largely because Israel is a nation that is most threatened by hostile use of UAVs, particularly small commercial ones increasingly used by Islamic terrorists and criminal gangs.

What makes Drone Dome different is its heavy use of electronic sensors to detect and jam the control signals used by UAVs, leaving the laser as a last resort. Several AUD systems are already in service and effective because they are good at detecting UAVs electronically and either jamming those control signals or taking over the control signals and capturing (by making it land) the UAV. Troops in Iraq and Syria were asking for AUD systems that used lasers and better UAV detection systems as well those with jammers to disable UAVs. There is a need for AUDs that can detect and destroy UAVs that do not use control signals and basically go on pre-programmed missions guided by GPS. This can be to take photos or deliver a small explosive. Usually, it is to take photos and return. Drone Dome is one of several AUD systems equipped to detect and locate UAVs operating in pre-programmed mode and destroy or disable them quietly with a vehicle-mounted laser.

AUDs similar to Drone Dome also use one or more radar systems and one or more sensor systems for detecting UAV control signals and/or visual images. These can use pattern recognition software to quickly identify what it is. While commercial UAVs are more common, the basic design principles have not changed. AUDs are constantly evolving to better detect and disable or destroy unwanted UAVs. The best ones are recent models that tend to be very expensive and used only for extreme situations, like UAV defense in combat zones.

The U.S. Air Force has been developing two AUD systems that use strong microwave electronic transmissions to disrupt the electronics in UAVs and cause them to crash. The air force has tested two such weapons which differ mainly in terms of range and price. The system already sent to a combat zone is THOR (Tactical High Power Microwave Operational Responder), which is a $10 million system that is shipped in and used from a standard 40-foot shipping container. The container can be hauled around on a flatbed truck or placed on the ground. Inside the container is a microwave transmitter that looks like a large satellite dish mounted on a base that can quickly rotate the dish to face the threat and transmit a short burst of microwave energy. Range of THOR has not been revealed but based on work already done on “directed energy” systems and the fact that THOR is powered by a generator that is also in the shipping container, the effective range is probably not more than a few hundred meters. The microwave energy is sufficient to damage the electronics on commercial UAVs used by Islamic terrorists to carry “swarm attacks” on military bases in Syria. Such attacks have frequently been used against a Russian airbase in western Syria, near the Mediterranean coast. The U.S. Air Force fears its bases, especially temporary or permanent ones overseas, could be subject to similar attacks by commercial UAVs carrying small payloads of explosives and using GPS to guide the UAVs to a base where the explosives detonate and cause damage. Such attacks have been used successfully in Yemen by Shia rebels and in one case attacked a large military ceremony and caused a lot of casualties. In late 2020 a TOR system was shipped to an unidentified African location to provide base defense against UAV.

Still in development is a longer-range system called CHIMERA (Counter-Electronic High-Power Microwave Extended-Range Air Base Air Defense) that began realistic testing in 2020. THOR has already downed groups of UAVs in tests and the air force wants to buy many systems for base defense in areas threatened by swarm attacks.

The microwave energy systems used by THOR and CHIMERA are similar to the EMP (Electromagnetic Pulse) weapons developed since the 1990s to destroy electronics in general. Since the 1950s it was known that the powerful EMP put out by nuclear weapon detonations could damage or destroy solid-state (transistors and microelectronics) devices over a wide area. Since the 1990s, devices using high-powered microwave (HPM) devices have been developed to create focused EMP on demand without all the nuclear blast and radioactivity. The most commonly mentioned device to generate HPM is the AESA (Active Electronically Scanned Array) radars that are becoming standard equipment in modern warplanes. AESA is more reliable and, increasingly, no more expensive than the older mechanical (a small dish that moves around inside a dome) radar. AESA is also easier and cheaper to maintain, which makes a more expensive AESA cheaper, over its lifetime, than a cheaper (to buy) mechanically scanned radar. More and more nations (including China and Russia) are manufacturing AESA radars and equipping their ships and aircraft with this stuff. All these nations are also manufacturing or developing EMP “bombs” that could be used to sabotage military bases or civilian facilities. For a long time, EMP was believed to be an unlikely threat because you needed a nuclear war to create EMP. Naturally, the blast and radiation damage from the nukes was seen as more of a threat than EMP. But now that has changed.

Airports, especially the large ones, will be driven by legal liability concerns to join the military in buying the latest AUDs, which at least lowers the AUD price and inspires even faster innovation and development. Commercial airports are increasingly having flight operations disrupted by the presence of commercial UAVs (usually cheap quadcopters). These UAVs are not terrorist weapons but used by someone making videos and unaware (or not caring) of the illegality of using a UAV close to an airport. AUDs for these situations must meet certain reliability, range and effectiveness goals in order to sell profitably. That is where military users will find another source for effective base defense systems.




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