Evolving surveillance technology keeps police helos one step ahead

 - August 28, 2007, 9:39 AM

Police and emergency services helicopters have undergone a dramatic metamorphosis since the mid-1980s, evolving from the equivalent of the Sopwith Camel to a worthy contemporary of the Eurofighter Typhoon, according to McAlpine Helicopters commercial director Dick Richardson. McAlpine, a Eurocopter distributor, outfits public-service helicopters in the UK.

The Twin Squirrel delivered to London’s Metropolitan Police in 1987 was the public-service equivalent of the Sopwith Camel, minimally equipped but comfortable and able to fill the requirements of a police helicopter. “The main role is observation, and it could move accurately and quickly,” he told a recent conference on the future for public-service helicopters. Each helicopter McAlpine has equipped for the emergency services during the intervening years has shared 85 to 90 percent commonality with its predecessor, but the small capability improvement achieved with every installation has transformed the police helicopter from something close to the standard model to “something incomparable to anything anybody else flies,” Richardson said.

For communications, Richardson said, most forces have converted to the Tetra trunk radio, essentially a sophisticated mobile telephone that “has the potential to do for police communications what the mobile phone did for [civilian] communications.”

The first observation aid was the Nitesun 30 million-candlepower searchlight. Since then, forward-looking infrared (FLIR) and tv cameras have been added; now the searchlight can be used as a decoy to make a suspect think his pursuers are looking elsewhere while the infrared camera is trained on him.

The unit’s three EC 145s represent the Eurofighter end of the evolutionary scale and feature a video management system supplied by UK airborne surveillance equipment specialist Skyquest Aviation. Each aircraft has five multifunction mission displays and four digital video recorders, enabling operators seated anywhere in the aircraft to select any or all sensor images for viewing on their display and forwarding to microwave downlink or onboard recording equipment. Normal crew is a pilot and two observers.

Touch-screen interfaces on the displays enable users to control other equipment such as moving maps, radar and license-plate recognition computers on their screens without the need for multiple control panels. Police observers can view all the information from the multi-sensor camera system along with a moving map, for example, and select the picture that provides the most useful information.

A comprehensive video management unit can be routed to each display with a single cable. The cable manages the distribution of all signals on the aircraft and handles signal conversion and amplification to allow all displays to view the same image without any signal loss.

Richardson said he does not see the development pace of sensor technology slowing anytime soon. As a result, mid-life upgrades are not enough. “The helicopters need frequent upgrades,” he said.

Making the Most of Available Information
The Metropolitan Police helicopters carry L-3 Wescam MX-15 turrets that combine daylight tv, spotter scope and infrared cameras. An Essex Police EC 135 houses
a similar sensor suite along with searchlight, public address system and antennas in a pod under the fuselage that helps keep the cabin clear and reduces drag for maximum Category-A performance. The London unit wanted to be able to remove the searchlight for daylight operations, and the turret has a far less significant effect on the performance of the EC 145.

The pilot has his own mission screen, and the observers can use it to show him whatever they want him to see, Richardson said, noting, “A large proportion of spots of suspects and of the information coming in comes from the pilots’ eyes.”

Being able to show the output from the three sensors along with the moving map “vastly improves the quality of tracking and information supplied to the ground. Trying to follow a vehicle on a paper map and give directions to the ground was a nightmare.”

According to Sgt. Richard Brandon, technology and training manager for the Metropolitan Police, the force worked with McAlpine for two years to integrate the five mission screens, and the imagery is used for tactical operations and contingency planning. “We’re just starting to realize how important that is after the July 2005 bombs.” He declined to discuss specific tactics, conceding only that the fleet is used increasingly for surveillance: “We can do a lot of covert work where people would never know what we are looking at.”

Most police forces are not exploiting their infrared capability to the fullest, he added. “You can record the imagery, put it in a bag and analyze it later; it might have vital evidence. In the past we wouldn’t send a helicopter if the suspect was not in a contained area. Now we just send it and vacuum up imagery of the whole area,” he said.

Brandon said the force’s air support unit flies 3,300 hours each year on 10,000 tasks and tries to have two aircraft available 24/7. Sixty percent of its activity is related to searches, including surveillance ahead of big events and looking for missing people or vehicles, and it is the only round-the-clock source of aerial imagery that can be delivered to the security services as well as the police within 30 minutes.

The helicopter is particularly cost-effective for searching large areas, Brandon said, enabling three people to cover in 30 minutes an area that would take 20 people on the ground 24 hours to search at 20 or 30 times the cost.

For the future, Richardson said, environmental impact–specifically noise–is likely to be a big concern. Manufacturers are improving technology to make their helicopters quieter. For example, the MD Explorer and the EC 135 were much quieter than earlier models. While the bigger EC 145 is not silent, it is much quieter than, for example, the BK117. Eurocopter is developing active blade control to reduce vibration and noise, and improvements in sensor performance will enable police helicopters to operate effectively at higher altitudes, “but they will still need to get close to the ground if they want to shine a searchlight on it.”

In the absence of tiltrotor or compound aircraft, the maximum realistic speed is likely to remain at around 150 knots, he added. Other predictions include an increase in direct operating costs as a result of rising prices of raw materials; the cost of stainless steel, for example, has doubled because of demand from China and India. Unmanned aerial vehicles offer the advantage of extended endurance, and the absence of onboard crew would make them much less expensive to operate.