Evolution of UAVs employed by Houthi forces in Yemen

Since 2016, Ansar Allah 'Houthi' forces have deployed unmanned aerial vehicles (UAVs - commonly called 'drones') in an increasingly lethal fashion against Saudi-led Arab Coalition forces in Yemen and across its borders.

Initially, Houthi forces  crashed unarmed UAVs  into the Coalition's Patriot surface-to-air missile defence systems. Since then, they have deployed UAVs with explosive payloads and over greater distances. In mid-2019, for example, the Houthis conducted a  string of attacks  using UAVs against installations in Saudi Arabia.

In July 2019, Houthi forces unveiled a  collection of UAVs , which they claimed to have manufactured domestically. Eight types of Houthi-manufactured UAV have been identified in media reporting: Hudhed-1, Raqib, Rased and Sammad-1 (Reconnaissance UAVs - although the Sammad-1 can be weaponised), and Qasef-1, Qasef-2K, Sammad-2 and Sammad-3 (Combat UAVs).

Between October 2016 and September 2017,  Conflict Armament Research (CAR)  documented nine UAVs and one UAV engine, which United Arab Emirates (UAE) Presidential Guard forces had seized in Yemen.

CAR is an independent investigative organisation that tracks the sources of weapons, ammunition, and other military materiel that have been diverted into the hands of non-state armed actors. CAR's field-investigation teams co-locate with national governments and local security forces on the ground to document illicit weapons that have been captured, surrendered, lost or left behind during fighting. CAR's EU-funded  iTrace  project is the world's most powerful public access weapon-tracking database.

This storymap highlights some of the key physical characteristics of two different UAV systems, the Qasef-1 and Sammad-pattern UAVs. It also maps the distribution of key components found in UAVs and IEDs recovered in the region. These findings come from CAR's February 2020 dispatch,  'Evolution of UAVs employed by Houthi forces in Yemen'.  

The Qasef-1 is a first-generation, rudimentary UAV in service with Houthi forces in Yemen. It is virtually identical in design, dimensions, and capability to the Iranian-manufactured  Ababil-T  UAV.

The Qasef-1 has an estimated maximum range of  200 km ; when operated from the  western part of the country  (where the Houthis hold control) its targets are therefore restricted to those that are on Yemeni territory. Recently, Houthi forces have fitted the Qasef-1 with improvised fragmentation charges (including nuts and bolts), which are initiated in flight and directed at soft targets, including exposed personnel below.

The most notable use of these charges took place on 10 January 2019. A Qasef-1 UAV (or Qasef-2K, which looks almost identical; it is impossible to identify which of the two models was used in the attack) detonated in the sky above a Yemeni government base during a military parade. Six people were reportedly  killed .

CAR has previously concluded that the Qasef-1 UAV is not of indigenous design and construction, but rather manufactured in Iran and supplied in batches to Houthi forces in Yemen.

Between October 2016 and July 2018, CAR documented eight Qasef-1 UAVs, as well as one engine recovered from a Qasef-1. The UAE Presidential Guard forces seized these items in Yemen. Seven of the Qasef-1s, which CAR documented in 2016–17, were manufactured on a production line, were identical in construction, and had matching internal components. In contrast, the eighth Qasef-1, which CAR documented in July 2018, had a frame and attachments whose construction was relatively rudimentary.

The fuselage and wings of the Qasef-1 UAVs bear printed and written serial numbers, which correspond to handwritten serial numbers applied to various internal components. The serial numbers, some of which are consecutive, indicate that the UAVs were manufactured on the same production line and that an external source supplied them to Houthi forces for further assembly. The components display a relatively high degree of precision in their fabrication; they are well assembled and markings on the electronic components point to industrial production and quality control processes. Some internal components match those found in Iranian-made UAVs.

In July 2018, a CAR field investigation team documented a Qasef-1 UAV that UAE forces reportedly captured in an unidentified location on the western coast of Yemen on 18 April 2018. While the UAV’s engine and internal components are mostly identical to those of the industrially manufactured Qasef-1s, the frame is poorly constructed and comprises both industrially produced parts and crudely moulded fibreglass parts. CAR suspects that Houthi forces may have produced this hybrid frame domestically.

While many of the commercially produced internal components are small and easy to smuggle, the UAV frame is much larger and would be more difficult to transport discretely. As CAR reported in 2018,  Houthi forces have the ability to manufacture IEDs on a semi-industrial scale , which suggests that they may also possess the tools and expertise to produce parts for UAVs.

In an effort to expand the reach and impact of their UAV capabilities, Houthi forces began deploying a new, more advanced UAV—the Sammad—in mid-2018. According to various media releases, the UAV comes in  three variants . In addition to its distinct design, the Sammad features a larger warhead than the Qasef-1, and it has a more powerful engine, which provides it with a longer effective range.

The Sammad has an estimated maximum range of 1,500 km, which supports claims by Houthi forces that they maintain the  capability to strike targets outside of Yemen . The Sammad has the same exterior cast and paint colour as the imported Qasef-1.

In September 2018, CAR documented a Sammad-pattern UAV, which UAE forces reportedly had captured on Yemen’s west coast on 21 June 2018. Several of the components resemble those of the Qasef-1, but with a few notable differences.

While Houthi forces appear to have developed some domestic UAV production capacity, the bulk of evidence gathered from Houthi UAVs recovered by UAE forces, and documented by CAR, reveals that a number of UAV components are identical to components and parts that proliferate elsewhere in the region.

For instance, some items contained in Houthi UAVs match ones that CAR identified in Iranian-made UAVs, in IEDs employed by non-state forces in Yemen, and in IEDs that Bahraini forces captured from militant factions in Bahrain. These components are also identical to some of the ones recovered from the Jihan 1 merchant vessel, whose cargo originated in Iran. The Jihan 1 was intercepted off the southern coast of Yemen in January 2013, and was discovered to be carrying a significant quantity of conventional military materiel that the UN Panel of Experts has stated was likely bound for the Saada governorate in Yemen—the Houthi movement’s stronghold.

Use the filters on the app below to see where components have been identified across different corresponding UAV and IEDs that have been recovered in the region, including in Bahrain, Iraq, Israel, Sudan, and Yemen. Clicking on each filter (e.g. Bahar enclosure box) will show the items that were found to include that specific component - clicking on each pop-up will then reveal more details about identified commonalities, including photos of the components themselves.

The use of these components in the documented UAVs and IEDs does not imply any wrongdoing on the part of the manufacturers.

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Since March 2015, when the current conflict in Yemen began, Houthi forces have demonstrated an increasing ability to inflict damage through the use of UAVs. They deploy a variety of reconnaissance and combat UAVs, which they have assembled using imported parts, or a combination of imported and domestically manufactured components. Their use of UAVs has evolved thanks to growing domestic capabilities, and to their acquisition of more sophisticated materiel from external sources.

Having previously relied on un-weaponised UAVs to destroy Saudi-led Arab Coalition weapon guidance systems—by crashing them into sensitive electronics, such as radar units—Houthi forces now employ longer-range UAVs, which are designed to deliver an explosive payload. These forces appear to have started producing a hybrid UAV, parts of which are manufactured domestically, rather than utilising only externally sourced industrial models. Since airframes are the largest component of a UAV, they are presumably more difficult to smuggle into the country.

Houthi forces continue to rely on smuggling smaller components, whose design and construction are increasingly sophisticated, rendering the UAVs capable of delivering increasingly lethal payloads.

The components and parts found in Houthi UAVs are in many cases identical to those used in the construction of IEDs by non-state forces in Yemen and Bahrain. Some components are also identical to those contained in Iranian UAVs and among components seized from the Jihan 1 merchant vessel, which Yemeni forces interdicted while the ship was ferrying weapons from Iran to Yemen.

As the UAV threat continues to evolve in the Gulf and wider Middle East, it is critical to assess commonalities in device construction and in the supply routes used by the various entities operating across the region. Enhancing knowledge of non-state groups’ capacity to obtain and use commercially available components for lethal means, and the lines of supply with which such material is procured, is key to identifying the parties responsible for their supply.