Print Friendly, PDF & Email

Very small unmanned aerial vehicles (UAVs) are providing even the lowest echelon infantry units with advanced situational awareness capabilities.

Various terms are used to categorise unmanned aerial vehicles (UAV) with a diameter of 2-50 cm: Very Small UAV, Micro-Drone, Micro UAV, Micro-UAV, Nano-UAV, or simply Micro Air Vehicles (MAV). Despite the disagreement over terminology, armed forces (a well as civilian public safety agencies) globally recognise their utility.

French concept for an insect-mimicking UAV.
Credit: XTIM

For humanitarian and public safety missions, Micro-Drones can fly through the rubble of collapsed buildings or mineshafts to quicky search for survivors, or be inserted into pipelines and utility shafts to inspect their integrity. Militarily, the small, highly portable aircraft provide units down to the squad or fire team level – or even the lone-operative – with an integrated short range Intelligence, Surveillance and Reconnaissance (ISR) asset with capabilities previously restricted to medium and upper echelons. The data is relayed directly to the operator in real-time, enabling frontline tactical units to immediately act on that intelligence, be it by avoiding an ambush, calling in artillery strikes on beyond-line-of-sight (BLOS) targets, or planning a hostage rescue operation. In addition to optronic sensors, Micro-UAVs can be equipped with sensors to detect biological, chemical or radiological agents, or with Signals Intelligence (SIGINT) sensors to intercept enemy radio and cellular communications. In this context, MAVs can be equipped with modified cellular technology to gather communications data and transfer it to receiving stations. While Micro-UAVs are usually remote controlled, Artificial Intelligence (AI) permits autonomous operations over much of the mission profile.

MAVs have several advantages over other unmanned aerial vehicles. In tactical scenarios, their small size (and associated small acoustic and thermal signatures) makes them difficult to detect, enabling operators to gather intelligence and targeting data without warning the enemy. The smallest MAVs can be carried in an ammunition pouch, resulting in minimal extra burden to the soldier. The aircraft are controlled via hand-held consoles or via laptop, tablet or mobile phone apps, again minimising or eliminating any logistical burden. Given their size, they can enter into buildings or other enclosed or access-denied areas where other UAVs cannot go. Performance parameters of Micro-UAVs vary, especially with size. ‘Larger’ micro-UAVs typically fly at altitudes up to 125 m (although some go considerably higher), and can achieve speeds of 50 m/s (180 km/h). Smaller systems typically have more limited performance, but are inherently more difficult to detect. Very small UAVs are frequently designed to mimic flying animals, whether insects or birds. This makes their visual detection much more difficult.

Black Hornet PRS

The iconic MAV system is the Black Hornet Nano developed by Norwegian firm Prox Dynamics AS. Development began in 2008, with serial production commencing in 2012. The early PD-100 variant became one of the first micro-UAV to be widely fielded, and was used extensively by Western forces in Afghanistan. The Black Hornet Personal Reconnaissance System (PRS) is currently marketed internationally by Prox’s parent company Teledyne FLIR Systems. The PRS is built around the Black Hornet 3 UAV, and is considered the world’s smallest high-performance ISR platform, providing dismounted soldiers with autonomous, mission-critical situational awareness. It is in service with the armed forces of the United States and several European nations, as well as global security partners, with more than 12,000 units deployed worldwide.

The Black Hornet Micro-UAV.
Credit: US DoD

Measuring 16×2.5 cm and weighing 18 g including batteries, the UAV can easily be held between two fingers. It carries three zoom-capable cameras with complementary fields of view, and captures both motion video and high definition still imagery as well as audio. According to Teledyne FLIR, upgraded features found on the latest models include removable mission data SD cards, increased processing capability, improved user interface, robust chargers, and enhanced vision-based navigation. Teledyne FLIR emphasises that imagery is transmitted back to the operator via an encrypted data link with ranges up to 2 km, permitting surveillance and targeting of opposing forces at well beyond visual line-of-sight. The 25 minute operational window can be extended by replacing the battery in the field. FLIR now also offers the Black Hornet Vehicle Reconnaissance System (VRS). Armoured and mechanised vehicles can carry up to eight Black Hornet UAVs in an externally mounted carrier, permitting immediate BLOS reconnaissance without exposing the vehicle’s occupants.


The RQ-28A short-range reconnaissance (SSR) system was selected as the Army’s first quadcopter UAV in February 2022 following a competition comparing six different platforms. First units were fielded to the 75th Ranger Regiment in late-2022. The Army describes the SSR as an inexpensive, rucksack-portable, vertical take-off and landing (VTOL) small UAV capable of providing integrated ISR capabilities at the small unit level. The SSR is currently being treated as a platoon-level asset. Low-rate initial production (LRIP) will encompass 1,080 units, to be delivered through the second quarter of Fiscal Year 2025.

Members of the British Army’s Yorkshire Regiment pose with a US Army RQ-25A unmanned aircraft system during Project Convergence 2022.
Credit: US Army

The RQ-28A is produced by California-based SkyDio, and is based on the firm’s X2D UAV, which was designed for the military market. The carbon-fibre and magnesium frame has been ruggedised for military applications. The four arms which support the rotors are folded for carriage. When folded the unit has LWH dimensions of 30×15×10 cm. Skydio states that the unit can be made mission ready within 75 seconds. Mission ready, it measures 66x56x20 cm (the size makes the X2D very borderline for the Micro-UAV category, but might explain why the drone’s performance was deemed superior to its competitors). The unit weighs 1.3 kg and can accommodate a 150 g payload. The basic kit includes the drone, a games console-style controller, two batteries plus a charger, all packed in a ruggedised carrier. Reconnaissance sensors include six gimbal-mounted 4K60P HDR colour navigation cameras with 16× zoom, as well as a FLIR Boson 320 thermal lens with 8× zoom. The integrated Skydio 3D Scan mapping software package renders recorded imagery as 3D models for enhanced situational awareness. With a service ceiling of 3,700 m, an airspeed of 11.1 m/s (40 km/h), the RQ-28A can perform covert overwatch by circling a location of interest or following moderately fast moving targets. Encrypted reconnaissance data can be wirelessly transmitted to the operator in real time, and its maximum transmission range is 10 km. Alternatively, the data can be recorded for offline retrieval upon the drone’s return to the platoon. Battery life is 4.5 hours per charge, but maximum flight time per mission is 35 minutes.


One of Skydio’s competitors for the SSR contract was French drone-maker Parrot. The firm has begun manufacturing its ANAFI drone in the United States. The variant optimised for military intelligence and reconnaissance operations is designated as ANAFI – USA MIL. The US-built system is also being marketed to European armed forces as well as to the US and Japanese coast guards. A variant geared to the needs of police and public safety agencies (ANAFI – USA GOV) is exported worldwide to support domestic security and disaster relief operations and to monitor critical infrastructure.

The UAV has been described as a ‘flying camera’ with two 32× continuous zoom sensors for 21 MB still imagery and 4K video, and a FLIR Boson 320 long-wave infrared (LWIR) camera. The cameras can detect human-sized targets at a distance of 2 km, or read a license plate from an altitude of 130 m. At 1,500 m the resolution sufficient to discern details of around 10 cm in size, or details of 1 cm in size at 150 m. Zoom is lossless, with up to 15× magnification. To maximise information value, the image management system can combine thermal and visual camera input into a single image.

The ANAFI – USA military reconnaissance micro-drone.
Credit: Parrot

The drone body and propellor blades are made of polyamide, reinforced with carbon fibre and streamlined using hollow glass beads. The broad rotor blades are inspired by the pectoral fins of humpback whales, and are optimised for superior lift performance as well as reduction of acoustic signature. The 500 g UAV takes off and lands in the hand of the operator. Unfolded, the aircraft dimensions are 28×37×8.4 cm. Flight endurance is 32 minutes per battery charge, and the system is sold with three interchangeable batteries to enable prolonged operations. The UAV’s service ceiling is 5,000 m, its maximum flying speed is 15 m/s (54 km/h), and its maximum climb speed is 3.9 m/s (14 km/h). The UAV can operate between temperatures of -35 to +49 °C, and is protected against the effects of sand or moisture. The US Coast Guard considers the ANAFI – USA the only small drone with a consistent and reliable capability to conduct take-off and recoveries while under way in a marine environment. Its military customers include the British Royal Air Force, the Finnish Army, and the Spanish Navy.

In January 2021 the French military procurement agency DGA initiated Parrot’s largest single order to date. According to the firm, the five-year contract for 300 Parrot micro-drones (plus support equipment) was later updated to 400 units. Deliveries began in June of 2021. Some 60% of the order are destined for the land forces (conventional and special operations), with the rest for the naval and air forces.

Spirit Coaxial UAV

The Spirit coaxial UAV system produced by Ascent Aerosystems represents a different architecture concept than the majority of Micro-UAV. The modular, tubular structure of the UAV body has basic dimensions of 25.7 cm in length and 10.6 cm in diameter, with an empty weight of 1.8 kg without battery or payload. When equipped with payload modules, the length increases depending on the payload, and after deploying rotors, the UAV has a blade tip-to-top diameter of 65 cm. Spirit exhibits significantly superior payload capacity compared to most micro-UAVs, with a combined payload and battery weight capacity of 4.3 kg.

The Spirit coaxial UAV.
Credit: Ascent Aerospace

Performance parameters also exceed most micro-UAVs. The direct drive with two brushless electric motors enables top speeds of 27.8 m/s (100 kph) and a service ceiling of 5,000 m. Mission endurance varies from 16 to 53 minutes, depending on battery and payload selection. Multiple payloads can be stacked depending on mission requirements. The quick-twist payload attachment system allows easy mounting of modular sensor units. As described by the manufacturer, dual HDMI inputs support simultaneous use of two airborne sensors. The unit deploys from any type of terrain and operates in all climate zones, including desert and arctic. The Spirit UAV is under consideration by the US armed forces.


Not all Micro-Drones are restricted to ISR missions. In November 2022 Israel’s Elbit Systems introduced a small-scale loitering munition designated ‘Lanius’. According to Elbit, the weapon system is designed for both tactical reconnaissance and for targeted killings in urban areas. Based on a civilian racing quadcopter, the highly manoeuvrable UAV achieves a top speed of up to 20 m/s (72 kph) outdoors. The Lanius’ small lithium battery limits flight endurance to a maximum of seven minutes, placing significant operational restrictions on the system. This limitation is partially compensated for by the option of mounting up to three Lanius drones on a larger UAV ‘mothership’ which transports the Lanius closer to the site of interest. The Lanius can also land to monitor a point of interest – such as a doorway – and resume flight operations when a triggering event occurs.

Flight operations, beginning with take-off, are mostly autonomous. This includes recognition of access points into structures. The drone’s 30×30 cm dimensions permit almost unrestricted passage through open doorways and windows. Both outdoors and indoors, the drone’s Nvidia Jetson AI uses the optronic sensor data and a simultaneous localisation and mapping (SLAM) algorithm to continually build and update 3D maps of the environment.

Three Lanius Micro-UAV on a ‘mothership’ UAV.
Credit: Elbit Systems

Assassination of combatant or high-value targets is performed via a 150 g close proximity, high explosive charge. While the Artificial Intelligence software embedded in the Lanius can distinguish between armed and unarmed personnel, activation of the payload requires a direct command by a human operator via a hand-held interface. Control options include Wi-Fi and software-defined radio communications. The Lanius UAV can be deployed individually or as part of a drone swarm coordinated through the Elbit Legion-X system which enables joint operations by unmanned systems of the same or differing types, as well as manned-unmanned operations.


From a distance, the smallest MAVs can be mistaken for insects. This is one of their prime advantages for covert reconnaissance applications, especially indoors. Some military agencies want to go further, developing true biomimetic capabilities. In June 2021 the US Air Force Research Laboratory (AFRL) – which has been at the forefront of biomimicry research and development – signed a non-exclusive patent license agreement (PLA) with California-based Airion Health LLC. The PLA authorises the firm to use government-owned patents to develop a prototype biomimetic micro-robotic aircraft able to perform insect-like manoeuvres. The true innovation would be the use of flapping wings to achieve six degrees of flight (up, down, forward and back, left or right), since the flight pattern would be virtually identical to that of a living creature. According to a June 2021 AFRL statement, “controllable forces would be generated by the wings based on position and velocity profiles, resulting in time-varying wing upstrokes and downstrokes which, at times may be asymmetrical.”

In early 2022 the French Agence de l’innovation de défense (AID; ENG: Defence Innovation Agency) announced it would be funding the BioFly project aimed at developing stealthy ISR drones which imitate the flight of birds or insects. According to the AID, the use of flapping wings enables a multitude of flight possibilities (beaten, gliding, almost hovering) with combinations of multiple trajectories which cannot be replicated by fixed-wing or rotary UAV. The AID release stated that an operational BioFly would weigh circa 50 g and be remotely operated via smartphone. The project is being conducted in association with several academic institutes and the Marseilles-based XTIM SAS, a leading French producer of biomimetic systems.

The French Defence Ministry’s BioFly biomimetic UAV program is based on a 2014 concept design for a bird-shaped drone.
Credit: XTIM

However these particular projects develop, it remains only a matter of time before micro-UAVs which are virtually indistinguishable from birds or insects – even at close range – are developed.

Sidney E. Dean