After establishing themselves as leaders in the development of unmanned aerial vehicles, Israeli manufacturers are expanding to a new surveillance field—tethered hovering platforms.

These are lightweight, readily deployable devices that provide persistent surveillance on land or at sea. Data can be transmitted down to a nearby ground station or, via integrated data links, farther away.

A new company called Sky Sapience has unveiled HoverMast (see photo, p. 26). Equipped with four thrusters and a central fan for lift and stabilization, HoverMast lands without the need for additional recovery systems and comes in a small container that can be quickly installed on a vehicle.

With the push of a button, the container opens, and HoverMast ascends 50 meters (164 ft.) within 15 sec. Gabriel Shachor, a retired Israeli air force brigadier general, formed Sky Sapience with a group of engineers. It works with another Israeli company called Controp, which manufactures sensors that can be installed on HoverMast for missions. The 10-kg (22-lb.) platform carries 9-kg payloads.

HoverMast is primarily for military surveillance, observation and target acquisition, as well as deployment of communications gear, communications intelligence and other electronic devices. But it is also described as an affordable application for border surveillance, urban security, crowd control and other civil uses.

The platform has a coaxial counterrotating ducted fan for lift, with four thrusters for station keeping, maneuvering and stabilization. The cable tether provides power and a wide-band data link. Payloads consist of electro-optic sensors, laser designators, radar or signals intelligence sensors. Data is transmitted to remote users or through the tether data link to a base station.

HoverMast gets its power from the vehicle it deploys from, and is designed so that personnel who are unfamiliar with such drones can readily operate it.

Sky Sapience developed HoverMast in response to a requirement by Israel's defense ministry for a lightweight tethered hovering platform. The system was one of several concepts evaluated by the ministry's research and development directorate (DDRD), which selected HoverMast as prime developer of the technology. Under a partnership with DRDD, Sky Sapience designed the platform and conducted prototype flight tests.

Sky Sapience also has a strategic partnership with G-Nius Unmanned Ground Systems Ltd., whose Guardium-LS multi-purpose, autonomous unmanned ground vehicle was selected for integration with HoverMast. Other applications include the Zibar light reconnaissance vehicle from IDO off-road industries.

Shachor says HoverMast compares favorably with the telescopic masts mounted on surveillance vehicles, offering faster response, lighter weight and the capability to operate on the move. Moreover, the platform alleviates the need to operate from horizontal surfaces and is less sensitive to wind gusts. In the stowed position HoverMast folds into a compact 72-cm-dia. (28.3-in.) container that can be carried on the bed or roof of manned or unmanned vehicles, or on small naval craft.

The development of HoverMast follows that of another hovering drone: the Electric Tethered Observation Platform (ETOP) from Israel Aerospace Industries (IAI), which is somewhat larger and carries a 20-kg payload.

ETOP also takes off, hovers and lands without special landing and recovery systems. It can be deployed from a static or moving ground vehicle or station. ETOP is the first of a line of hovering platforms being developed by IAI for military and civil applications. It has four ducted rotors in a configuration with enough space for payloads at the center of gravity. These could be IAI's MiniPOP or MicroPOP electro-optical stabilized payloads or lightweight ground-surveillance radars. Electric power for the propulsion system, sensors, flight control and communications are fed from the ground through the tether, which extends 100 meters. Hovering time is limited by the ground platform's energy-storage capability.

Companies outside Israel are working on similar systems. One such is Bertin Technologies of France, which offers the HoverEye vertical-lift drone. This comes in two configurations—light and heavy. The 0.5-meter-dia., 70-cm-high model is 4 kg, and carries 0.3-kg payloads on 10-min. missions as far as 1,000 meters (500 meters beyond line of sight), at 20 kph (12.4 mph.).

The heavy version weighs 10 kg, is 70 cm in diameter and 110 cm high, and lofts 1-kg payloads on 20-min. sorties over 5 km (1 km beyond line of sight). Both use electric propulsion.

HoverEye has automatic and semi-automatic flight modes and auto-pilot, auto-hovering and obstacle avoidance. The system is equipped with day/night imaging sensors and mission-specific payloads such as bio-chemical sniffers, communications gear and improvised explosive device detection sensors.