Major developments have taken place in fixed-wing UAVs which operate from land. Some of these have been adopted for operating from ships but special modifications are required for take-off and landing which is a complex process. To overcome this drawback, naval rotary UAVs (NRUAVs) have been developed to operate from ships. NRUAVs can perform all the maritime UAV missions with the addition of search and rescue but without the problems of ‘landing and take-off’ of fixed-wing UAVs. They can easily be used by the navy and coast guard. They can also operate from land thus are very useful for central police forces and homeland security. NRUAV can provide ‘Over the Horizon’ surveillance which extends the reach of the ‘eyes’ of the mother ship by day and night. It is capable of carrying an array of sensors in order to take on multiple roles. NRUAV provides the ship’s captain an integral tool for carrying out his operational role more successfully as it extends the search area, allows more time over the target area and provides mission flexibility. NRUAVs are ideally suitable for the dirty and dangerous missions which otherwise would be undertaken by manned systems.

It is more pragmatic to develop a NRUAV from a existing proven helicopter platform than to develop a new platform. It will cost less, will be more reliable as it is already in service, short time for conversion into a rotary UAV and there will no requirement for stringent checking by the local aviation authorities.

Role of NRUAV

Role of NRUAVs is similar to fixed-wing UAVs but they can also operate with ease from a ship with much shorter reaction times. Possible roles of NRUAV are:

• Intelligence, surveillance and reconnaissance (ISR) including identification
• Targeting information, target designation and real time battle damage assessment.
• Support littoral warfare and provide coastal surveillance.
• Protects the country’s interest in the exclusive economic zone (EEZ).
• Support search and rescue (S&R) operations.
• The surface/ground control stations can be networked so that all the NRUAV resources of the fleet can be synergised to produce a common operational picture. Such a network can also facilitate transfer of control of NRUAVs from one control station to another.
• Can provide real-time persistence surveillance and integrated with manned maritime patrol aircraft.
• Provide information on mine countermeasures, hydrography and meteorology.

Current NRUAVs

Saab’s Skeldar V-200. It is a medium-range UAV system which can hover for a long time over designated area while providing realtime information. It is a fully autonomous, vertical take-off and landing NRUAV from ship decks, controlled by commands such as “Point and Fly” and “Point and Look”. It is designed for land, maritime and civil applications. Launch and recovery requires only minimum logistics. The Skeldar system consists of two air vehicles and a mobile control station. Based on operational and technical requirements, the system may be integrated into a wide variety of segments and system environments utilising a common control concept and user interface in the context of command, control and payload management. Its maximum take-off weight is 235 kg, carries a payload 40 kg, service ceiling 3,500 m, max speed 140 kmph, endurance is 6 h, mission radius (D/L)> 100 km, Takeoff and landing area 10 ft diameter. Skeldar is available with a number of different advanced COTS payloads for information collection and dissemination and has dual payload capability. The payload suite can include long-range EO/IR gimbals, Surveillance and SAR radars, EW payloads, communication relay, AIS, IF transponders, etc. The architecture is open for quick integration for future payloads.

Airbus Defence and Space (earlier Cassidian) Tanan 300. TANAN™ 300 is a new-generation compact VTOL tactical UAS (vertical take-off and landing tactical unmanned aerial system) for maritime and land missions. TANAN™ 300 is a real ‘eye in the sky’ thanks to a full HD imagery chain and to its main payload which allows an easy switch between EO/IR highdefinition cameras. It was also exhibited during the Paris Airshow in June 2013 and the Defexpo in India in February 2014. TANAN™ 300 includes very high-capability payloads, such as an AIS, an IF system, a maritime radar, an electronic surveillance system and a direction finder, for multi-role requirements. It carry out intelligence, surveillance, target acquisition and reconnaissance missions very efficiently. Its endurance is over eight hours. Has an open, modular architecture and the latest generation of proven equipment. The maritime radar system allows it to carry out search, detection and tracking missions on the coast. It can detect a target with a radar cross section of 1m2 beyond 15 nautical miles in sea state 3. The AIS identifies details of ships such as vessel size and vessel name up to 20 characters. TANAN™ 300 is capable of completing missions with ranges of up to 100 nm/180 km and a 50 kg payload. The maximum take-off weight is 300 kg. The system can fly at a maximum altitude of up to 4,000 metres above sea level. It can be further integrated with other payload systems based on the operational requirements.

Northrop Grumman’s MQ-8B Fire Scout. Northrop Grumman’s Fire Scout vertical take-off and landing (VTOL) tactical unmanned aerial vehicle (UAV) system provides exceptional situation awareness and precision targeting support for US Navy with minimum impact on host ship operations. It has the ability to autonomously take-off and land on any aviation-capable warship and at unprepared landing zones. US Navy earlier had RQ-2 Pioneer UAV in service which was a fixed wing UAV. US Navy started looking for a VTOL UAV and finally selected Ryan-Schweizer UAV during 2000. It was named Fire Scout and was a derivative of Schweizer three-passenger, turbine powered 330SP helicopter with modifications like a new fuselage and fuel system with matching electronics and sensors. The system includes advanced control stations that encompass the US navy’s tactical control system, tactical common data link, and robust communications. A modular mission payload capability allows continued growth into new payloads. With a total endurance of over eight hours, the Fire Scout can provide more than six hours time on station with a standard payload at 110 nautical miles from the launch site. A pair of Fire Scouts can provide continuous coverage at 110 nm. The electro-optical/infrared sensor integrated with laser rangefinder/illuminator and a maritime radar, enables the Fire Scout to detect, acquire, identify, track and illuminate targets thus providing accurate targeting data to strike platforms and subsequently perform battle damage assessment. It can act as a communication node due to its multiple V/UHF radios within the network-centric warfare environment. Its gross weight is 1,428 kg, engine is Rolls-Royce 250-C20W Turboshaft Engine, speed is 115+ knots with a ceiling 6.1 km. Payloads can be EO/IR/LRF/mine detector/communication relay/maritime radar. Advance version of MQ-8B is MQ-8C which will have increased range of plus 30 per cent, double the endurance and an increased payload capacity. Earlier Northrop Grumman had offered to convert a Eurocopter Gazelle helicopter for unmanned trials by incorporating the operating system off MQ-8B Fire Scout.

Indian Perspective

India is jointly developing with Israel Aerospace Industries, a NRUAV with Chetak (Alouette II) as a platform. It is likely to have an endurance of 6 hours and a range of 120 km. It will have communications and sensors to carry out the role of a classic NRUAV, for example, its radar could detect a patrol boat from 80 nautical miles, automatically detect and track surface targets and effectively handle 64 airborne targets. Among the sensor suites that can be carried by the NRUAV are different maritime surveillance radar systems, capable of surface and countersubmarine operation, resolution sharpening, synthetic apperture radar (SAR) and Inverse SAR modes. The electro-optical payloads can accommodate a SIGINT/COMINT Suite like the EL/K-7071 COMINT and EL/K-7071 Sigint systems; and EL/L-8385 electronic Support measures. Among the optronic payloads, stabilised plug-in optronic payload (POP) family on display includes POP300LR Observer (includes a thermal imager with a new long-range zoom lens, a colour CCD with a new long-range zoom lens, a wide angle CCD and an optional eye-safe laser rangefinder), Mini-POP and multi-mission optronic stabilised payload—MOSP3000. The entire sensor suit is controlled from the ship’s command information centre. However, the option of Northrop Grumman’s MQ-8 Fire Scout, Saab’s Skeldar V-200 and Airbus Defence and Space’s Tanan 300 is still open to India.