Aerial maritime surveillance, reconnaissance and information gathering, as well as patrol missions have traditionally been carried out either by specialized long-range multi-engine aircraft specifically designed for extended flights over the sea, or by commercial platforms adapted for such tasks. These aircraft were typically used to monitor large areas of the sea surface, including monitoring shipping and other activity along critical routes of communication and in Exclusive Economic Zones (EEZs).
However, the cost of acquiring and operating manned platforms imposes an unbearable burden on many countries and the respective air and naval forces, and therefore various maritime security structures may face problems in carrying out systematic monitoring of sovereign waters due to lack of funds. air patrols and a small number of sorties.
The need for an affordable alternative to manned naval reconnaissance aircraft inevitably contributes to the growing interest of many countries in land-based and sea-based unmanned aerial systems (UAS), especially those with large EEZs and common protected borders. At the same time, other countries want to have on-board sensor systems capable of increasing the situational awareness of deployed civil and military vessels by providing the necessary information.
Modern UAS, especially medium-altitude and high-altitude drones with long flight duration (MALE and HALE categories), have proven themselves well as reconnaissance and strike platforms in support of ground operations, having such characteristics as long range, long mission duration and the ability to carry sensor target loads. While these aircraft-type platforms are required to launch and land on the ground, their inherent capabilities nevertheless attract the maritime community looking for a means of observing large areas.
At the other end of the spectrum are smaller VTOL aircraft-type UAVs that have also gained widespread acceptance in recent years. Such regular surveillance and reconnaissance equipment can be quickly launched and returned, collecting information on request in order to ensure the operation of ships.
MALE class platforms
As in the case of manned patrol aircraft of coastal aviation, the ability to cover long distances and patrol for long periods of time is an important quality of the MALE class multipurpose UAS adaptable for such tasks. The developers have also identified other desirable characteristics, including a large payload, allowing you to carry both long-distance communication systems and on-board equipment of various types.
The Israeli company Elbit Systems is promoting a specially configured version of its Hermes 900 MALE UAV, which is operated by at least eight operators. The aircraft, mainly used in ground surveillance operations, is capable of receiving target loads of both its own design and third parties.
According to the company, the Hermes 900, with a maximum take-off weight of approximately 1180 kg and a wingspan of 15 meters, can take up to 350 kg of target equipment, including 250 kg in the 2.5 meter long internal compartment. In a marine configuration, the aircraft can be equipped with a specialized marine surveillance radar, an automatic identification system and a stabilized optoelectronic / infrared sensor system and electronic warfare and reconnaissance equipment.
Elbit Systems noted that its universal ground control station can offer a mode of simultaneous control of two UAVs using two redundant data transmission channels. The company claims that this has a positive effect on the utilization of the system, saves human resources and operating costs. The drone also benefits from the integration of a long-distance over-the-horizon communication system based on a satellite channel and the integration of the Elbit System's proprietary maritime automated control system.
Haji Topolanski of Elbit Systems said:
“Although the Hermes 900 takes off and lands only on the ground, the control of the UAV itself and the operation of its sensors can be integrated into the ship's command and control system. This allows ships to receive reconnaissance information from UAVs in real time and use it at their own discretion."
Since April 2019, at the request of the European Maritime Safety Agency, Hermes 900 drones have been used to patrol maritime areas. Iceland was the first country to use this service. According to Elbit Systems, the Icelandic maritime authorities have identified the Hermes 900 as the eastern airport of Egilsstadir, from which it can cover more than half of the country's EEZ. This unit has also been modified to withstand the high winds and ice conditions inherent in the North Atlantic.
“It is obvious that a naval aircraft-type UAV, operating from a coastal base and controlled from a ground station, should have a different performance and target load than a land observation system. In particular, the need for wide area reconnaissance dictates the integration of powerful multi-mode radar with imaging to detect and classify objects at long ranges and high-resolution long-range OE / IR systems for positive identification and imaging."
- explained Topolanski.
“In addition, line-of-sight data transmission channels and a satellite channel for over-the-horizon communications are being integrated into the marine LHCs. The fact that a marine drone sometimes needs to descend for positive identification of objects with the help of its surveillance station and fly below the radio frequency horizon increases the importance of the broadband over-the-horizon channel.”
Meanwhile, Israel Aerospace Industries (IAI) has delivered naval versions of its Heron 1 MALE UAV to the Indian and Israeli fleets.
The Heron 1 drone developed by its Malat Division has a takeoff weight of 1100 kg and a payload of up to 250 kg. Its standard payload is IAI Tamam's bow-mounted Multi-mission Optronic Stabilized Payload, which includes a high-resolution camera, an infrared camera and a laser pointer / rangefinder.
According to the company, the aircraft is powered by a 1, 211 cc Rotax 914 four-stroke engine that rotates a two-blade, variable-pitch pusher propeller that develops up to 100 hp. maximum continuous power at altitudes up to 4500 meters. This allows loitering at a speed of 60-80 knots and reaching a maximum speed of 140 knots with a flight duration of up to 45 hours, depending on the carrying load. A line-of-sight data transmission channel in a mobile or stationary version provides control within a radius of about 250 km, although when installing a satellite communication kit, the range is increased to 1000 km.
IAI engineers note that the Heron 1 has two internal cargo compartments with a total volume of up to 800 liters - the bow and center compartments with a volume of 155 and 645 liters, respectively.
The distance from the lowest point of the fuselage to the ground is 60 cm, which allows the device to be equipped with external target loads, while on-board power generation of up to 10 kW gives the platform the potential for upgrades, and also allows the installation of powerful systems, for example, the IAI Elta EL maritime surveillance radar. / M-2022U or modular surveillance radar for reconnaissance of ground moving targets EL / M-2055.
According to Jane's C4ISR & Mission Systems - Air handbook, the EL / M-2022 Marine Surveillance Radar can track a variety of targets at ranges up to 200 nautical miles. When used in inverse aperture synthesis radar mode, the radar is capable of capturing suspicious objects and determining their type.
In addition to the standard surveillance station and marine radar, the naval Heron 1 can also carry electronic intelligence systems, for example, the IAI Elta ELK-7071 or ELK-7065 systems. The typical cycle of detecting and identifying suspicious surface objects begins with target detection, after which the electronic reconnaissance systems are turned on to determine the direction and belonging of the object through the automatic identification system, then during the subsequent approach, the species reconnaissance station is used for visual verification.
HALE platforms
"The pinnacle of technical thought in the field of marine UAVs is the US Navy's MQ-4C Triton reconnaissance drone of the HALE category (high-altitude long-duration flight), which is scheduled to be ready for service in April 2021, and full-scale production will begin two months later."
The MQ-4C Triton drone developed by Northrop Grumman has a length of 14.5 meters and a wingspan of 39.9 meters, a declared range of 2000 nautical miles and a flight duration of up to 24 hours. The drone was developed on the basis of the Block 30 RCMN naval version of the US Air Force RQ-4 Global Hawk drone as part of the Broad Area Maritime Surveillance Demonstrator program in order to provide the fleet with continuous monitoring of sea areas.
While the basic design of the MQ-4C is very similar to the RQ-4B, it still features significant modifications aimed at optimizing performance for long-term surface missions. For example, the aircraft will feature active control of the center of gravity of the fuel system, an improved antenna radome with increased strength and improved aerodynamics, an anti-icing air intake system, as well as a reinforced wing structure with protection against air gusts, hail and bird entry, lightning protection and a reinforced fuselage to increase the internal target load. … Together, these improvements allow the MQ-4C UAV to descend and rise if necessary, which is necessary to check ships and other objects at sea.
Under the fuselage, the main sea search radar AN / ZPY-3 of the X-band with an active phased antenna array is installed, in which electronic scanning is combined with mechanical rotation of 360 ° in azimuth. Northrop Grumman says the MQ-4C's flight duration and ZPY-3 sensor coverage radius allows the MQ-4C to survey over 2.7 million square feet in a single flight. miles. The radar is complemented by the Raytheon AN / DAS-3 MTS-B sensor station, which provides day / night image and high-resolution video with automatic target tracking, as well as the AN / ZLQ-1 electronic reconnaissance system from Sierra Nevada Corporation.
While the drone is still in development, the Australian government has pledged to buy two MQ-4C platforms for the country's Air Force on the Air 7000 Phase IB project. The first aircraft is expected to enter the Air Force in mid-2023. By the end of 2025, the purchase of six platforms, worth $ 5 billion, is planned to be deployed at Edinburgh Air Force Base in South Australia.
The US government also approved the sale of four MQ-4C drones to Germany in April 2018 for $ 2.5 billion. Aircraft under the local designation Pegasus (Persistent German Airborne Surveillance System) must be modified in accordance with national requirements.
Shipborne TANK
Shipborne or deck-based drones have attracted close attention of the military in recent years. Of particular note are the well-known complexes, for example, the aircraft type ScanEagle developed by Boeing-lnsitu and the helicopter type Fire Scout from Northrop Grumman, deployed by the US Navy. At the same time, the Boeing-lnsitu group also delivered the Integrator winged vehicle to the Marine Corps under the designation RQ-21A Blackjack.
With the existing deficit of space on the decks of most modern ships, interest in the LHC with vertical take-off and landing, apparently, is only increasing in other fleets. For example, the Swiss company UMS Skeldar is looking to replicate its recent success with its newest V-200B rotorcraft, which was purchased by the Canadian and German fleets.
The company's newest platform, V-200 Block 20, with a take-off weight of 235 kg, has a 4-meter fuselage, which is most likely made of carbon fiber, titanium and aluminum; it is equipped with a two-blade propeller with a diameter of 4, 6 meters, a ventral compartment and a non-retractable two-ski landing gear. The UMS Skeldar drone has a top speed of 150 km / h and a service ceiling of 3000 meters.
Improvements to the engine and fuel management system have reduced weight by 10 kg compared to the previous model V-200B, while increasing the flight time to 5.5 hours with a target load of 45 kg or more by reducing the time spent in the air. Other improvements include a new data link, an update to the vehicle's electrical configuration, and an eight-camera system for visual detection and ranging that can track targets up to 20 miles in each direction. It can also be equipped with phased array antennas that enable the operator to transmit images in real time.
The V-200, said a UMS Skeldar spokesman, "includes a Hirth Engines heavy fuel engine that can run on Jet A-1, JP-5 and JP-8 fuels, one of the main benefits for the maritime industry."
"The two-stroke engine configuration also provides a long MTO along with the added assurance of landing and take-off in an environment where conventional fuels are banned, all of which are very important to maritime operations."
According to him, the V-200 platform requires less material and technical maintenance and has functional flexibility comparable to other aircraft and helicopter-type options in the same weight category. “The V-200 UAV is compatible with the STANAG-4586 standard, which pre-qualifies the UAC for military use and integration with other systems,” he added. “We also thought well about easy integration with various battle management systems, including the Saab 9LV naval combat system, which provides command and control capabilities for offshore platforms of all sizes, from combat boats and patrol vessels to frigates and aircraft carriers.”
Meanwhile, the Austrian company Schiebel has developed a helicopter-type Camcopter S-100 UHC, which is equipped with a two-blade propeller with a diameter of 3.4 meters and has a streamlined carbon fiber fuselage with dimensions of 3, 11x1, 24x1, 12 m (length, width, height, respectively).
The device with a maximum take-off weight of 200 kg can carry up to 50 kg of cargo along with 50 kg of fuel. The rotary engine allows you to fly at speeds up to 102 km / h with a practical ceiling of 5500 km. With a payload mass of 34 kg, the flight duration is 6 hours, but with the installation of an external fuel tank, it increases to 10 hours.
According to Schiebel, a typical marine surveillance payload includes Harris Wescam's L3 optoelectronic station, the Overwatch Imaging PT-8 Oceanwatch camera for scanning large areas and detecting small objects, and an automatic recognition receiver.
“The S-100 platform is ideal for offshore environments due to its minimal logistics and size,” a company spokesman said. "Its compact size and light weight means it can be easily maneuvered, stored and serviced in ship hangars … a typical frigate hangar can accommodate up to five S-100 drones along with a conventional large manned helicopter." The platform has also been integrated with 35 different types of ships, having flown over 50,000 flight hours.
The Camcopter S-100 helicopter was purchased under the Australian Navy Minor Project 1942 program, which is aimed at meeting the needs of the country's fleet for an intermediate shipborne UHC. Further, according to a separate program, a suitable UAV will be selected for integration with 12 coastal patrol ships, the first two of which are being built at the shipyards of ASC. Then, another type of UAV will be selected to equip nine Hunter project frigates, which will be built for the Australian Navy.
Schiebel announced in November 2015 that it had completed testing a heavy fuel engine for the Camcopter S-100 helicopter. Modification of the S-100 propulsion system based on a commercial rotary piston engine has led to a reduction in weight due to the modernization of the exhaust system, a new engine control unit and new batteries. The engine allows the S-100 to use JP-5 fuel, which has a higher flash point than aviation gasoline.
The company is modernizing the S-100 platform primarily with an eye on the synergy (interaction) of manned and uninhabited platforms and delivery at the last section. In April 2018, it was announced that it was collaborating with Airbus Helicopters in a joint demonstration involving the H145 crewed helicopter and the S-100 UAV. According to Schiebel, a ground control station for the drone was installed aboard the H-145, allowing level 5 interoperability to be achieved by transferring full control of the drone to the operator on board the helicopter, including launch and return.
New target loads
New target loads for UAVs expand the range of tasks of naval UAVs and go beyond reconnaissance and observation operations. For example, L3 Harris is developing the SDS (Sonobuoy Dispenser System), which is designed to quickly repurpose various types of aircraft for anti-submarine missions.
SDS leverages the experience of creating pneumatic systems SRL (Sonobuoy Rotary Launch) and SSL (Sonobuoy Single Launch) for Lockheed Martin's P-8A Poseidon multipurpose anti-submarine and anti-ship patrol aircraft.
The SDS is based on the Modular Launch Tube (MLT), which the company describes as "an individual launch station for launching one A-size buoy from a standard LAU-126 / A launch canister." The company has also developed a modernization tandem launch kit that allows the LAU-126 / A container of size A to accept buoys of two sizes F or G.
MLT is an external loading system with a rotary bayonet lock for attaching a buoy with a dead weight of approximately 4.5 kg. It is equipped with a buoy presence sensor to ensure confident capture and launch; the buoys are ejected under a loading pressure in the system from 70 to 105 kg / cm2.
According to L3 Harris, the SDS system can consist of any number of MLT rails, a ground-charge pneumatic trigger, and an electronic control unit with a universal type-1/2 interface on top of a MIL-STD-1760 interface. All of these components can be integrated into a dedicated external container.
The company sees a growing interest in the world in UAVs for long-range and long-term maritime patrols as an affordable replacement for expensive patrol aircraft, for example, P-8A aircraft. However, they note the potential limitations of the SDS concept, given that anti-submarine aircraft, such as the R-3 and R-8A, can carry 87 and 126 buoys, respectively.
"It is impossible to load an SDS system in flight, unlike a manned aircraft, so ideally we see many SDS-equipped drones working together in groups or flocks to create an acceptable solution from a sufficient number of sonar buoys."
Uttra Electronics is also developing its own concept of the SMP (Sonobuoy Mission Pod) dropping machine, which it offers for unmanned and manned aircraft.
According to the company, the SMP can be mounted on an external MIL-STD-2088 suspension point, which would allow existing platforms to be remodeled for anti-submarine missions. The SMP system can accommodate 25 to 63 buoys in sizes G and F to accommodate small and large platforms.
The system is designed to operate at altitudes up to 10 km at flight speeds up to 150 knots. It can drop buoys at 2.5 second intervals and is compatible with several Ultra Electronic buoy models including ALFEA (Active Low Frequency Electro-Acoustic) and HIDAR (High-Instantaneous-Dynamic-Range) and Mini HIDAR.
Although land-based LHCs are fairly common these days, the use of such systems in the maritime sphere is happening on a smaller scale today. However, the situation seems to be gradually changing, as fleets, coastguards and other maritime security structures increasingly understand how effective MALE and HALE drones can complement manned platforms in maritime patrol and other operations, or, if possible, be used as separate ones. funds.
There is growing interest in established airborne patrol capabilities for marine vessels, but there are still several challenges that need to be addressed. For example, on smaller ships there is not enough space on the deck, the use of such aircraft in conjunction with crewed helicopters is usually limited to the “either - or” situation, when the launch and recovery process must be carefully timed and agreed in order for the drones to remain in the air no longer than is necessary while waiting for the deck to clear. It is also difficult to recover damaged platforms when the deck is busy and cannot be emptied due to an emergency.
