UAV threat, has wide spectrum. On one end is the security threat of terrorists weaponising small commercially available drones. ISIS is already using them in in Syria and Iraq to carry small improvised explosive devices. They can also be used to disperse biological or chemical agents. These are small in size (e.g., < 55 lbs.) making them difficult to detect, they fly at low altitudes (e.g., < 400 ft) which make them easily hidden by background urban structures, they are slow (e.g., < 90 kts) which make them difficult to differentiate from other targets like birds. In addition they also have low IR signature and depending on model may generate small amount of acoustic noise.
Other end is military threat of military UAVs of China, which is manufacturing full equivalent of western UAVs Yilong like Predator, Soaring Dragon like Global Hawks, Dark sword is UCAVs. One of their characteristic is most of them have large payload capability in tons because of which they can carry large amount of weapons. Endurance and stealth is also fast becoming close to American counterparts.
Counter-drone technology, also known as counter-UAS, C-UAS, or counter-UAV technology, refers to systems that are used to detect and/or intercept unmanned aircraft. Many C-UAS technologies are being developed from shoulder-mounted launcher system to physically capture it, silent cyber weapon that floors a drone instantly, anti drone cannons, Electronic Counter Measures (ECM) like jamming of command and control links and GPS spoofing, counter drone Directed Energy Weapons both laser based and electromagnetic weapons.
Drone detection and neutralization technologies
To countering UAV threat many drone detection and neutralization technologies have been developed. One is the SkyWall system, a shoulder-mounted launcher system that fires a projectile that in turn deploys a large net to physically capture it, and then it also deploys a parachute to bring it down safely.
Phantom Technologies has launched Eagle 108 Tactical Jammer designed for the detection and jamming of drones. It has been designed to neutralise unauthorised drone / quadcopter that has entered a secured field / campus / sport event. The system uses passive detection scheme, scans using an array of directional antennas. Once a threat is detected, an automatic command to the jamming unit blocks all radio communication channels. Forcing the drone to drift away and lose communication with its operator. The detection radius is more than 1km and jamming radius is up to 2km.
US Army has modified its Counter missile Enhanced Area Protection and Survivability system to counter drones. System has been successfully tested by shooting down a class 2 unmanned aerial system using command guidance and command warhead detonation at Yuma Proving Ground, Arizona. The system uses a precision tracking radar interferometer to detect and track UAVs, a fire control computer to perform computations, a radio frequency transmitter and receiver and a standard 50-millimeter Orbital ATK Bushmaster III cannon to launch command guided interceptorsgnss. Army says it has range of more than a kilometer.
The most comprehensive commercial system is British AUDS system that claims to counter micro, mini and larger unmanned aerial vehicles (UAV) or drones. The system can detect a drone five miles (8 km) away using electronic scanning radar, track it using infrared and daylight cameras disrupting the flight using an inhibitor to block the radio signals that control it. Latest version features a quad band radio frequency (RF) inhibitor/jammer, as well as optical disruptor. The quad band inhibitor disrupts the different licensed telemetry bands of commercial drones no matter where in the world they are designed and licensed for use. For example, both the 433 and 915 MHz frequencies commonly used by unmanned aircraft systems (UAS) can be disrupted as can the 2.4 GHz control band and the global satellite GNSS bands ( 1575 MHz, 1227, 1176, 1278 MHz)
The optical disruptor can be utilised for both pointing at a drone for identification purposes and disrupting the automatic gain control settings in the drone’s camera system such that the operator loses visibility. The optical disruptor can also provide a very precise identification of known UAV launch activity to any ground forces.
Next are Directed-Energy Weapons use directed electromagnetic energy as a means to degrade damage or destroy enemy equipment, sensors, facilities etc. The two types of DEW technologies currently being operationalized are high power lasers and high power microwave weapons.
High-power lasers, excite atoms to release bursts of coherent (single-frequency, single-phase) light that is focused with mirrors to a precise point on the target and destroys it by overheating. NATO notes that several demonstrations have shown the ability to destroy inflight UAVs with 10’s of kilowatts at ranges greater than 2 km. Based on low or medium power can dazzle or destroy electro-optical sensors on target. High power – can defeat the target structure- Effectiveness depends on target construction, material, and range.
Electromagnetic directed energy weapons.
RF Directed Energy Weapons, either narrowband high-power microwave (HPM) or ultra wideband (UWB) uses high intensity concentrated electromagnetic radiation (CW, Pulsed or Impulsive high voltage) to irradiate the target at a distance that gets coupled into its electronic equipments and disrupts its components, circuitry, and switches. Unlike Laser DEW, HPM DEW is in fact ‘SMART’ as it sneaks in and affects the target system through its most vulnerable points.
They can be classified according to type of electromagnetic waveforms that are generated: wideband (upto 2GHz, > 10%), ultra wideband (upto 2GHz, > 25%) and narrowband (1 to 35GHz, < 10%). RF Directed Energy Sources, either narrowband high-power microwave (HPM) uses high intensity electromagnetic radiation to irradiate the target that gets couples into its electronic equipments and disrupts the components, circuitry, and switches inside it.
Narrowband HPM DEW technologies which have frequencies generally 1 to 35 GHz and bandwidth less than 10% of the center frequency. The narrowband environments are pulsed CW waveforms in the gigahertz range with pulse widths of the order of microseconds. High-power Lasers excite atoms to release bursts of coherent (single-frequency, single-phase) light that is focused with mirrors to a precise point on the target and destroys it by overheating .
Ultra wideband type tries to generate Electromagnetic pulse (EMP) like waveform that is generated usually when a nuclear device is detonated in the upper atmosphere. EMP is comprised of the fast rise time E1 component, the lightning type E2 component, and the solar flare type E3 component. These waveforms having instantaneous fractional bandwidth greater than 20% of mean frequency. One of the example of UWB weapons is Electromagnetic Bomb (e-bomb) being developed by RCI / TBRL. They include high power narrow pulse fields (pulse widths narrower than 100 ps), which may be repetitively pulsed (up to 1 million pulses per second).
Raytheon technologies defeat multiple UASs in USAF exercise
Raytheon has demonstrated to the US Air Force (USAF) the ability of its advanced high power microwave (HPM) and mobile high energy laser (HEL) systems to down drones. During the demonstration, the HPM and HEL technologies engaged and defeated multiple unmanned aerial system (UAS) targets. Raytheon noted that these technologies can provide an affordable solution for the service to combat the growing UAS threat.The system is mounted on a Polaris MRZR all-terrain vehicle and is designed to detect, identify, track and engage UASs. Raytheon Electronic Warfare Systems vice-president Stefan Baur said: “Countering the drone threat requires diverse solutions. HEL and HPM give frontline operators options for protecting critical infrastructure, convoys and personnel.”
The HPM technology, which uses microwave energy to disrupt drone guidance systems, allows users to focus the beam to target and instantly defeat drone swarms. The system features a consistent power supply to ensure virtually ‘unlimited’ protection from threats.
Raytheon Advanced Missile Systems vice-president Dr Thomas Bussing said: “After decades of research and investment, we believe these advanced directed energy applications will soon be ready for the battlefield to help protect people, assets and infrastructure.” The firm’s HEL and HPM were the sole participants in the experimentation demonstration under the directed energy systems category. Previously, these systems downed 45 unmanned aerial vehicles and drones in a US Army exercise, known as Maneuver Fires Integrated Experiment, held in Fort Sill, Oklahoma.
Raytheon’s “Phaser” high-power microwave (HPM)
A new video cleared by the Defense Department shows Raytheon’s “Phaser” high-power microwave (HPM) weapon in a demonstration at the U.S. Army Fires Center of Excellence at Fort Sill, Oklahoma. Raytheon used the swarm-destroying Phaser to bring down Flanker and Tempest drones during the live-fire demonstration conducted Sept. 30-Oct. 3, 2013. Three years later, the Defense Department has cleared the footage for public release. Raytheon says it has already reduced the size of the Phaser payload by half and is offering the system up for operational use.
The HPM weapon is mounted on a 20-ft. trailer with power provided by an internal diesel generator. The Phaser system can detect and track threats using its own radar or be cued by third-party sensors. The device’s parameters can be set to “disrupt” or “damage.” In the demonstration offered to Aviation Week, , the Flanker and Tempest drones were detected, tracked and cued for destruction by a three-dimensional X-band Thales/Raytheon MPQ-64 Sentinel radar and vehicle-mounted Ku-band Close Combat Tactical Radar, with Raytheon’s radio-linked Command View-Tactical system providing command and control.
Russia develops High Power Microwave Weapon for protection against UAVs, Missiles and Rockets
In 2015, Russia’s United Instrument Manufacturing Corporation (UIMC), part of Rostec Corporation, announced that it developed a super-high-frequency gun for BUK missile systems.
The gun can reportedly disable drones and warheads at a distance of up to six miles and is scheduled to be demonstrated in a series of private tests. The system is capable of out-of-band suppression of the radio electronic equipment of low-altitude aircraft, unmanned aerial vehicles (UAV) and the warheads of precision weapons.
A representative from (state-owned) United Instrument Manufacturing Corp that built the weapon described the device to (state-owned) Sputnik News this way: The new system is equipped with a high-power relativistic generator and reflector antenna, management and control system, and a transmission system which is fixed on the chassis of BUK surface-to-air missile systems. When mounted on a special platform, the ‘microwave gun’ the impact range of the equipment is ten kilometers and capable of ensuring perimeter defense at 360 degrees
Russia’s Ranet E system
Russia had earlier developed Ranets E is a High Power Microwave (HPM) weapon system, first disclosed by Rosoboronexport in 2001, but little technical detail has been disclosed since then.
The weapon used an X-band pulsed 500 MegaWatt HPM source, generating 10 to 20 nanosecond pulses at a 500 Hz PRF, and average output power of 2.5 to 5 kiloWatts. The antenna is large enough to provide a gain of 45 to 50 dB in the X-band, for a total weapon weight of 5 tonnes. The weapon has been described as a “radio-frequency cannon” and Russian sources credit it with a lethal range of 20 miles against the electronic guidance systems of PGMs and aircraft avionic systems. Similar system could be used for neutralization of UAVs.
Directed energy Weapons are promising technologies for neutralizing UAVs but Increasing their efficiency and compacting their size are great technological and engineering challenges before they can be employed for the operational role.
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