Surveillance was once the task of specialized covert personnel; now it is the job of robotic systems. In particular, no matter the branch of the military, properly equipped unmanned aerial vehicles (UAVs) have proven their worth for remote information gathering for more than a decade. They are continuing to increase their value—not only for different aspects of defense-related activities, but on commercial airfields as well.
UAVs are evolving from what were once purely surveillance systems to what are now fighting machines. As an example, the Predator UAV from General Atomics Aeronautical Systems was developed in the mid-1990s as the RQ-1 Predator, with one human operator to pilot the vehicle and one to coordinate the surveillance activities. The original designation is now MQ-1 or MQ-1B Predator (Fig. 1), designating an armed system capable of multiple missions in addition to surveillance.
The UAV incorporates advanced communications capabilities (including satellite link), sensors, and precision weapons (AGM-114 Hellfire missiles) for performing strike, coordination, and reconnaissance (SCAR) against specialized targets of interest. It is similar in design and function to numerous other UAVs developed for intelligence, surveillance, and reconnaissance (ISR) missions, such as the same company's Guardian for maritime use; Predator-like Reaper, also driven by robust turbo-propeller-powered Honeywell engines; and the U.S. Navy's X-47B, produced by Northrop Grumman.
In its various configurations and designations, a Predator is 36 ft. long with a 66 ft. wingspan. It can fly at a maximum altitude of 50,000 ft. and can stay airborne for as long as 27 h per mission. It can handle internal payloads as large as 850 lb. and external payloads totaling 3,000 lb., including a Lynx multimode radar, automated identification system (AIS), combination system for signal intelligence (SIGINT) and electronic surveillance measures (ESM), C-band transceiver for line-of-sight communications, and Ku-band transceiver for satellite-communications (satcom) links. A Predator can take off and land using a runway that is 5,000 ft. long and 75 ft. wide (1,524 × 23 m).
A Predator equipment suite for long-term (such as 24-h) missions consists of four aircraft with imaging sensors and weapons, a ground control station, and a primary satellite link for effective long-distance communications. The aircraft can be controlled via the satellite link or by a line-of-sight data link. It includes two laser-guided missiles and an assortment of surveillance equipment, such as an infrared (IR) sensor, color/monochrome daylight television camera, image-intensified television camera, laser designator, and laser illuminator.
In a very similar configuration, the Predator is also known as the MQ-9 Reaper for multiple-mission ISR operations (Fig. 2). Equipped with Hellfire missiles and GBU-12 laser-guided bombs for attack missions, the Reaper is basically the same UAV platform as the Reaper, with identical dimensions, Honeywell power plant, and payload capabilities. As with the Predator, the Reaper handles missions over land or sea, features a triple-redundant flight-control system, and stores flight-control data and instruments via MIL-STD-1760 requirements.
The company recently reported that its collection of UAVs—or remotely piloted aircraft (RPA) as they are also known, including the MQ-1 Predator, the MQ-9 Reaper, and the MQ-1C Gray Eagle—had recently exceeded an impressive milestone: four million flight hours, with 90% of the time total having been devoted to combat missions. "Amassing four million flight hours is a testament to the reliability of RPA systems that are designed, built, and maintained by a dedicated group of skilled and innovative professionals," said General Atomics Aeronautical Systems CEO Linden Blue. "We are proud of our fleet's contributions in providing round-the-clock ISR capabilities for our customers worldwide."
The X-47B UAV (Fig. 3), which Northrop Grumman refers to as an unmanned combat air system (UCAS), has been developed with special capabilities (such as low probability of detection) for use by the Navy for maritime operations. It has been designed to help investigate the potential for an aircraft-carrier fleet of unmanned aircraft. Two of the tailless fighters were originally developed with the aid of a 2007 contract, as part of the Navy's UCAS demonstration program.
The X-47B was the first military UAV to be refueled in midair, demonstrating the possibility of extended duration missions. The fighter/surveillance aircraft is 38.2 ft. long, with a wingspan of 62.1 ft. The wings fold for compactness and portability. The X-47B, which can reach altitudes to 40,000 ft. powered by a Pratt & Whitney F100-PW-220U engine, has a range of 2,100 nautical miles.
As impressive as these early UAVs were for ISR applications, more recent development efforts for surveillance drones have led to ever-smaller micro air vehicles (MAVs). One company, Aerovironment has developed a series of MAVs based on research funded by a DARPA contract of about a decade earlier. Many of these MAVs are meant to provide undetectable surveillance in urban environments.
For example, the Wasp AE (all environments) is an MAV with wingspan of 3.3 ft. (102 cm), length of 2.5 ft. (76 cm), and weight of only 2.85 lb. (1.3 kg). Developed several years ago as a miniature unmanned aerial system (UAS), the Wasp has a line-of-sight range of 5 km and operates at altitudes to 500 ft. (152 m). It can be programmed for autonomous flight or remotely piloted with the aid of on-board GPS navigation for short-distance surveillance duties.
More recently, the same company unveiled the Snipe UAS (Fig. 4), weighing just 130 g and with a range of 1 km. The portable quadcopter is equipped with infrared (IR) and electro-optical cameras. Aerovironment is scheduled to deliver 20 to 30 Snipe prototypes to the Army by spring of 2017. According to David Sharpin, vice president of UAS business development at AeroVironment's UAS division, Snipe is an ideal surveillance tool for use in a city: "We want this to be able to interoperate with the solder. We want it to be able to look around buildings and under vehicles."
As with many electronic systems for defense applications, UAVs are also being designed to fit in smaller, lighter packages and by borrowing from nature. Many smaller UAVs in development mimic the structure of biological organisms, such as birds or insects, to achieve aerodynamic structures capable of efficient flight. At the same time, a number of major defense contractors are investigating various methods for combatting a UAV should troops ever be faced with a "rogue drone."