by John P. Desmond
It’s a bird, it’s a plane, no it’s a MicroUAV. A micro unmanned aerial vehicle.
A fair amount of research and some production is going on into microUAVs, including military applications, commercial efforts and university research. The activity is worldwide and for the most part, early-stage.
There are many trends driving microUAV work including the low-cost of microUAVs compared to other aerial vehicles, improved technology, more power capabilities, and new concepts of operations such as “swarming,” which opens the door to missions once not thought possible for small, low-cost and low-technology UAVs.
Several U.S. military services are engaged with microUAVs. The US Air Force is pursuing the Battlefield Air Targeting Micro Air Vehicle – or BATMAV – as an important new system expected to pass images into the cockpits of close support aircraft. The sensor imagery from BATMAVs would be forwarded via a radio linked to a ground stations. Other data from the microUAV would be sent to command and control centers, airborne mission aircraft or artillery via digital links. Each BATMAV system is to include two air vehicles, a ground control station, interchangeable payloads and a field operators support kit. Over 300 systems were planned to be acquired beginning in fiscal year 2007 and extending to fiscal 2011. The baseline system is required to have a minimum operating ceiling of 10,000 feet, and be inaudible to the human hear at distances over 500 meters.
The U.S. Army battle laboratory is planning to buy several prototypes of the Dragon Slayer microUAV from a private company, Miraterre Flight Systems of Tuscon, Ariz. Dragon Slayer is the company’s first product. It has a 13-in wingspan, weighs 10.6 ounces, has a top speed of 93 mph and an endurance of 35 minutes. For flight control, the Dragon Slayers uses Papparazi, an open source program. The US Army is likely to load a video camera onto Dragon Slayer.
The US Army is expected to operate Dragon Slayers in concert larger UAVs, which from a higher altitude could identify objects or persons of interest. The microUAVs would then be flown in to investigate further and provide more detailed images.
Miraterre founder and CEO Jeremy Tyler stated that in addition to interest from the military, the company has had interest from police forces and border security firms, companies that want surveillance of oil pipelines and power lines, and for forest monitoring.
CICADA for Mass Swarming
The US Naval Research Laboratory is developing a mass swarming, gliding microUAV intended for bulk distribution on battlefields. The Navy calls them close-in covert autonomous disposable aircraft – CICADA. The device is being described as essentially a “flying printed computer circuit board” which would fold for storage and transport. Several thousand of the gliding UAVs would be packaged together and carried into an arena by transport aircraft. The program was unveiled at the Unmanned Systems North American exhibition by the Association for Unmanned Vehicle Systems International, held in August 2007 in Orlando.
The prototypes on display incorporated a flight control system with integrated global positioning satellite guidance, mechanical actuators to support unfolding, a power source, a miniature communications system and a miniature electronic intelligence gathering sensor. The model calls for thousands of UAVs to be programmed simultaneously while in transit to where they need to operate.
The current packaging idea is that 18 individual CICADA could fit into a six-inch cube. A standard US Air Force carrier aircraft could hold 9,800 of the UAVs in a single flight. That number could “seed” an area of 1,850 square miles in 25 minutes. Each CICADA weighs seven ounces. On landing, multiples UAVs synchronize to establish a distributed network. The UAVs could operate collectively to provide a single large array for electronic intelligence gathering, or as a constellation of localized intercept stations.
The Naval Research Lab launched the development effort in 2006 after receiving a five-year funding green light. The target production cost per individual microUAV is $100.
More swarming research is underway at the University of Colorado in Boulder, where engineering and computer science departments are involved in the research. In a paper published in December 2006, the UC research team reported how hundreds of bird-sized micro aerial vehicles could cooperate and communicate over a wide wireless communication network. In this ‘SensorFlock’ project, the team designed the micro-air vehicle (MAV), created a semi-autonomous flight control algorithm capable of hovering the MAVs and studied the characteristics and flight and air-to-ground communications. The aim of the research was in part to aid with the eventual creation of hundreds of airborne test MAVs, and to understand understanding the challenges involved. Applications that could benefit from the work include chemical dispersion sampling and atmospheric weather sensing.
MicroUAV Communication Standards Pursued
The scope of microUAV development is extending into several military and commercial communication standards areas as well. For instance, the US Air Force Research Laboratory wants to development a miniature common datalink (Mini-CDL) for small UAVs, which would be interoperable with the US military’s existing airborne CDL architecture. The Air Force solicited proposals for two awards of up to $1.65 million each, to study advanced engineering, hardware construction and flight-testing phases. The proposal documents asked for the mini-CDL to be capable of being carried by UAVs up to 88 pounds maximum takeoff weight.
Existing CDL architecture products are unable to be used on microUAV systems because of weight and space restrictions, which has given rise to a number of data links unique to each platform.
And in the civilian arena, the Federal Aviation Administration has received a recommendation from the RTCA (Radio Technical Commission for Aeronautics), which advises on air traffic management safety, that the cutoff point between fully-certified UAVs and small or microUAVs should be defined. The RTCA intends to issue guidance on the weight limits for microUAVs in accordance with its mandate to develop and recommend regulations for unmanned air systems operated in unsegregated airspace. The standards body is also expected to develop minimum aviation system performance standards for the command, control and communications systems.
The FAA recently asked the RTCA to accelerate its effort because of pressure from industry and the military, which has been frustrated by the process to obtain approval to fly UAVs in civil airspace. The RTCA expects the performance standards to be completed in the 2010 “plus or minus” timeframe.
Meanwhile, the European aviation standards body Euroae kicked off a similar effort in 2006, expected to require that UAVs below 330 pounds be regulated nationally. The plan is to define best practices for a microUAV class covering the gap between radio-control models and the fully-certified vehicles.
As part of its efforts, the RTCA has determined that the industry must secure frequency spectrum for UAV operations at the World Administrative Radio Conference, which governs the allocation of communications frequencies. The issue was planned to be brought up at the 2007 WARC meeting, and a formal application for spectrum to be assigned to UAV operations is planned for the 2010 WARC meeting.
Indian Army Exploring MicroUAVs
Outside the U.S., the Indian Army is planning to buy an unspecified number of microUAVs to fly surveillance missions in the Jammu and Kashmire, and for anti-insurgency operations in the country’s northeast. Bids have been sent to companies that make the Bird Eye (Israel Aerospace Industries), FanTail (Singapore Technologies Aerospace), Raven (AeroVironment of the U.S.), Skylark (Elbit of Israel)( and Tracker (EADS of Europe). A spokesman for the Indian army, according to a report in Defense News of India, stated the services hopes to acquire more than 200 UAVs in the next three to five years, with expansion into urban areas planned beyond that.
The Indian bid documents specific that the microUAV selected need to: performance reconnaissance and surveillance over mountains, day and night; transmit data to operators by voice and data; identify and detect targets; assess post-strike damages; weigh no more than 40 kilograms; be easy to assemble; have a low-noise engine; fixed or rotary wings; a low heat signature; and ability to avoid detection. The systems’ ground control station needs to be a portable laptop that an display video and flight data and control the UAV in flight. The UAV also needs to be capable of performing a preprogrammed flight.
Out of Italy, private firm Advanced Aviation Technology (A2Tech) began working on a mini UAV in 2002 and plans to fly the RV-160 by May 2008. Trials of a prototype unit began in mid-2005, with 30 hours of flight time recorded through October 2007, according to a report in Flight International. The RV-02 has a span of 4.6 feet and weighs 4.2 pounds. The frame is made of molded, expandable polypropylene. The initial focus of deployment is to Italian domestic agencies, in response to natural disasters such as earthquakes and landslides.
The RV-02 features a remotely operated system A2Tech calls RealityVision. This “universal ground cockpit” replicates the forms and functions found in manned aircraft, such as the stick, pedals and panoramic display, via video goggles and integrated tools used by a human pilot on the ground. The company is also researching the potential of the microUAV to be used in Alpine rescue operations in Italy’s northern border. Autonomous flight in that region faces major technical hurdles due to wind and rapid weather condition challenges.
Stay tuned to Robotics Trends for further developments in the microUAV arena.
John P. Desmond is a Contributing Editor to Robotics Trends. He can be reached at john_desmond[at]king-content[dot]com.