Skyeton, Kyiv, has completed the full cycle of trials of its ACS-3 Unmanned Aircraft System (UAS) that is already awaited by the Ukrainian military. It might be hard to believe, but this small-factor UAS aircraft that weighs only 20 kg fully equipped can stay airborne for nearly 24 hours performing reconnaissance surveillance missions and feeding live video footage to it associated ground control station. In terms of air endurance, it has very few rivals of similar size and weight worldwide.

 

In designing the ACS-3 technology the Company focused on three key aspects: the airframe and its capabilities; the maximum possible degree of flight automation from takeoff to landing at the selected place; and reliability of operation and durability.

 

Designed for professional use, the ACS-3 UAV has an in-air endurance of ≥20 hours and can fly missions while transmitting live video streaming within a radius of ≥100 km. In terms of NATO UAS Classification by range, it could be classified as belonging to Class II (operational/theater, mission radius ≥50 km, LOS) or Class III (strategic/national, mission radius ≥200 km, BLOS).

 

 

In its current configuration the ACS-3 UAS consists of two UAV aircrafts with mission-specific payloads, a foldable catapult launcher, a ground control station (GCS), aerials and other support equipment, including spare parts and fixings, all transportable in four containers weighing collectively about 200 kg. The UAS can be transformed from unpack to operation by two personnel within 15-20 minutes.

 

The ACS-3 aircraft doesn’t require any screwdrivers, wrenches or other similar tools to assemble for use or disassemble for storing. It is launched by a mechanical catapult of a proprietary design developed by Skyeton. Landing is assisted by parachute to slow down its descent and with a reusable, electrically pumped airbag to cushion the impact on the airframe. While approaching the landing site, the aircraft “turns on its back” to minimize the risk of mechanical damage to payload equipment. It is powered by carbureted engine developing 3 hp (which on several occasions proved excessive for some of the routine missions tested), while electronic fuel injected engine is optional. Max operational ceiling is 3,000 m. Onboard starter/generator provides electric power to the mission and payload equipment and enables remote engine on/off control while in flight. Critical systems such as flight control surfaces and servos are duplicated to improve reliability and safety of operation.

 

 

During test missions, the aircraft was remotely piloted by a single operator. The ground control station can be vehicle mounted or deployed in open terrain, and needs only a few seconds of warm-up time. Equipped with an embedded large-capacity memory with three spaced display screens, the GCS is built to the IP67 environmental protection standard.    

 

Since the flight is highly automated from takeoff through flight to touchdown, the human operator’s duties are mainly limited to dealing with payload equipment. Modular architecture allows for payloads of up to 7 kg – ranging from a snapshot camera, gyro-stabilized camera, laser rangefinder or synthesized aperture radar – to be mounted in a stabilized gimbal. Payload packages can alternatively include radio relays and electronic warfare/countermeasure equipment. During the most recent trials, an ACS-3 aircraft was flight tested equipped with a gyro-stabilized OCTOPUS Epsilon 140 electro-optical and infrared (EO/IR) sensor gimbal. The Epsilon 140 has optical and digital zoom capabilities for recognizing, identifying, and tracking objects at day and night – with excellent image stabilization. It offers a 20 cm resolution at an altitude of 2 km, enabling a car license plate number to be read from 400 m away. The gimbal is able to lock on and automatically track up to five objects of interest, moving or static, simultaneously and to automatically locate the objects within its field-of-view. The aircraft can be optionally equipped with Epsilon 140Z gimbal integrating an optically zoomed IR camera with a laser designator/rangefinder.

 

 

As validated by a test mission using an indigenously developed ECM jammer, the ACS-3 UAS provides an improved counter-ECM capability that allows it to function effectively even in the presence of substantial jamming.

 

Regarding flight automation, Skyeton believes that the less a military or civilian user intervenes in controlling an aircraft flying a preprogrammed flight plan the better. This approach is resting on statistics gathered with ACS-3’s testing and operation. UAV flight automation is highly demanded since it allows for a shallow learning curve for new operators and offers operational benefits enabling safer and more efficient flight operation. But special emphasis placed on flight automation is more projected to the future. With a long endurance capability in place, several ACS-3 drones can be concurrently and collectively controlled from a single center. This would pave the ground for the use of the drones in swarms – an objective Skyeton is aiming for.

 

After completion of the recent cycle of trials, the ACS-3 developers and military experts reached a consensus to the effect that effective operation of long-endurance UAV drones requires adequate ground support and human operator training. Military experts particularly recommend the US experience, where long-endurance UAS are operated from 4x4 Hummer type truck vehicles, as is the case with RQ-7 Shadow-200 UAS operated by the US Army’s Stryker Brigade combat team. Each Shadow-200 unit operates three UAS with four drones each. Deployed from Hummer trailers, they are used for 24-h battlefield surveillance and reconnaissance missions logging 60 flight hours every day.

 

 

An optimal configuration of the ACS-3 UAS for use by Ukraine’s Armed Forces has been developed based on foreign and domestic experience. The ACS-3 UAS will consist of four drones, two catapult launchers, two GCS, aerials, and associated spare parts and fixings. Each of the drones will be available with a payload package consisting of snapshot camera and gyro-stabilized EO/IR sensor gimbal. The ACS-3 UAS will require two vehicular platforms to transport and operate from, each accommodating three workstations (for two operators and crew leader), and will be served by a crew of 11 personnel.

 

 

In terms of its performance capabilities, the ACS-3 represents one of the most advanced UAS technologies ever developed in Ukraine, according to the assessment of the MoD’s Armaments Testing and Certification Center, Chernihiv. Military officials have stated that the ACS-3 UAS fully conforms to the technical specifications required by Ukraine’s Armed Forces, and there is already a place reserved for it in the combat organization. But before this happens, one or several systems need to be purchased and user tested and evaluated. The Army needs an UAS technology that not just provides the required performances but is continuously improved and upgraded based on user feedback and is adequately maintained on the operating unit level. This should be proved not only on the testing site but in real service conditions as well.    

  

ACS-3 UAV Aircraft. Technical Specifications
Range of Radio Silence flight			≤ 2,500 km
Pre-programmed flight mission radius			≤ 1,000 km
Mission radius, with live video streaming and telemetry data transmission			≤ 120 km
Counter-ECM capability			Available
Endurance *varies with payload power output and aerodynamics, and with mission specifics			>20 hr
Max/cruising/min air speed			160/120/65 km/h
Max service altitude/*with electronic fuel injected engine			3,000/4500* m
Cruise altitude			1,000-2,000 m
Wing span/length/height			2,985/1,830/320 mm
Max takeoff mass			20 kg
Empty weight			9 kg
Propulsion			Single-cylinder four-stroke carbureted engine
Fuel consumption at cruising speed* *varies with payload power output and aerodynamics, and with mission specifics*			0.3-0.5* l/hr
Fuel tank capacity of standard-configuration drone			12 l
Propulsion power			3 hp
Method of launch			Catapult
Landing			Assisted with parachute and airbag
Size of storage/transport container for one drone			1,350 х 650 х 450 mm
Payload package
Options for payload packages, which are customer-specific, may consist of stabilized camera, snapshot camera, laser rangefinder, synthesized aperture radar, radio relays, electronic warfare/countermeasure equipment etc.
Payload mass		≤ 7 kg
Gyro-stabilized, multi-sensor OCTOPUS Epsilon 140Z gimbal Epsilon 140Z gimbal, which itegrates EO/IR sensors and laser designator-rangefinder, is capable of automatically tracking up to five objects, moving or static, simultaneously.
Mass		1.77 kg
Size		140 mm x 189 mm diameter
Environmental protection		IP64 rated
Operating temperature range		-25 … +50 °С
Rotation limits		360° continuous pan, -90° to +45° elevation
Video out		Digital 720р HD output, Н.264 encoded video
EO sensor Hitachi DISC120R		НD 720р, 1270х720 рх; x30 optical zoom lens
IR sensor Flir TAU2		SD 640х480 рх; x3.3 zoom lens, 18 - 60 mm
Laser rangefinder, Class I		range 5,000 m, accuracy <1 m
Laser designator, Class IIIb		Wavelength 830 nm; power 50 mW
Ground Control Station (GCS)		ACS-3 UAS. Operational specifications
Control system	Automatic	Operating temperature range		-25 … +50 °С
Video output/telemetry data bandwidth, MHz	Optional to Customer specification
		Prep time from unpack to launch		20 min
Transmission encoding	Available
Number of UAV drones controlled simultaneously/collectively from a single GCS *using a dedicated software package, up to four	1*	Time between landing and launch		10 min
Mass	7 kg	UAS stow time		20 min
		Min required crew		2 personnel

 

Serhiy ZGHURETS,

Defense Express

 

Read more in Ukrainian Defense Review by Defense Express Media & Consulting Company