Radar Assists Perimeter Control

From the June 16th 2008 Issue of Jane's Airport Security

Significant money and attention has been invested in passenger and baggage screening at airports around the world since the 11 September 2001 terrorist attacks on the United States. Yet no matter how sophisticated terminal-based equipment may be, perimeter security also demands attention.

Recent events at London Heathrow bear this out. A man carrying a rucksack was apprehended on 13 March 2008 having scaled the perimeter fence and run onto the live northern runway; this followed an incident in late February when Greenpeace activists also breached perimeter security at Heathrow and were able to climb on top of a B-777 aircraft.

A number of technological enhancements to perimeter security are available to offer greater control for airport operators - 'dumb' fences can be augmented with sensor-based perimeter intrusion detection systems that can use surveillance cameras and sensors to track the cause of an alarm.

UK-based Lochrin Bain, for instance, has teamed with sensor and test measurement group PCB Piezotronics of the US to develop a rivetless palisade perimeter system with integrated intruder-detection sensors for the homeland security market.

The Combi Fence has a clear potential application for airport perimeter security and has been tested at RAF Valley airbase, according to Adam Hardie, business development director at Lochrin Bain.

Growing Market

The market for such advanced perimeter fences in the UK commercial airport sector is "not significant, but getting that way", Hardie adds.

In the US, meanwhile, airports have taken steps to strengthen perimeter security. ICx Technologies, for example, was awarded a subcontract from Honeywell in the second quarter of 2007 to supply its STS 12000- and STS 350-series radars for perimeter surveillance at William P Hobby and George Bush Intercontinental airports in Houston, Texas.

Houston Hobby operates one STS 12000 and three STS 350 radars; three STS 12000s and four STS 350s are deployed at George Bush Intercontinental. ICx perimeter security products are in service at other US airports including Dallas Fort Worth, where several STS 350s are in active use.

The radars for Houston were installed in phases, with the final installation near the end of 2007. "The first phases have now been in place for 11 months," says Lynn Welch, director of marketing at ICx Technologies Imaging Systems.

The Houston airports previously had a limited installation of sensor fencing located close to the hangars and the area servicing luggage and air freight. "The majority of the airport complex perimeter was largely unprotected," Welch remarks. "The fence sensors provided a physical deterrent with limited CCTV devices. The CCTV systems were daylight-functional only, subject to functionality impact from weather conditions."

To improve this system, a large quantity of additional CCTV units, fences and fence sensors was required. "The CCTV/fence sensor solutions commonly produced numerous false alarms daily, with accompanying classification challenges," comments Welch.

Standard Doppler radars can produce hundreds of false alarms per day "as verified by USAF [US Air Force] testing", Welch says. ICx radars utilise a different radar technology known as frequency-modulated continuous wave (FMCW). Such systems in effect put a unique time stamp on the transmitted wave at every instant. As explained by the Federation of American Scientists (FAS), measuring the frequency of the return signal with an FMCW system enables the time delay between transmission and reception to be measured and therefore the range to a target object determined.

Fewer false alarms

"Our radars provide a much lower false alarm rate with a wider area of coverage per unit," says Welch. "The total cost of ownership for expanding perimeter security with a radar and thermal solution was less than expanding the existing system with additional CCTV and fence sensor units. ICx radars also provide a higher level of wide-area surveillance fidelity with lower false alarm rates and ease of classification and tracking."

The ICx radars and thermal imagers (supplied by a different company) at the two Houston airports are controlled from independent command centres "but could be integrated to share data if required in the future", remarks Welch. The system uses ICx radars for detection and thermal imagers for assessment. The radars provide detection with latitude/longitude co-ordinates for continuous precise tracking. The co-ordinates are relayed to thermal imagers for positive, 24-hour identification in all weather and light conditions.

Algorithms within the radar units continually analyse changes in the scene. The radars conduct continuous 360-degree sweeps around the clock. "If there is a change in an alarm zone, the alarm hit/response from the radar unit is instantaneous," says Welch. "This data is immediately communicated to the integrated command-and-control software."

Multiple and open command-and-control architectures are supported by ICx radars. In the case of Houston, the sensor-based system (including the third-party thermal imaging systems) is integrated into existing airport security systems through the Honeywell Vindicator Pro-Watch system. "The functionalities of the current airport systems are currently separate, but are observable from the larger airport security system," says Welch. "Direct command and control from the parent system can be integrated into the Vindicator system in the future if the client desires."

The integration process did encounter some problems between the third-party thermal imaging cameras and the Vindicator system. "The thermal cameras were not ICx thermal imagers, which ship with integrated industry-standard communications protocols on board," remarks Welch. "The integration communications issues were reconciled with selective software communication patches between the thermal imaging company and Honeywell."

Welch is unable for security reasons to give details of the radars' performance at the two Houston airports, but comments that "feedback from the client has been quite positive".

The security systems developed by companies such as ICx seek to push coverage out beyond the traditional perimeter fence - so is the situation foreseeable in which the fence itself becomes a redundant feature? Welch thinks not: "While there will always be a function for fencing as 'deterrence by presence', we will continue to see security products reach beyond the fence to enhance performance, response and increase awareness and safety," she says. "Fencing also serves as a line of demarcation, keeping out animals and extraneous hazards to airport runways. External sensors providing awareness far beyond the fence will improve and work with the basic functionality and purpose of the fence as a physical barrier."

Despite the growing acceptance of radar-based systems to strengthen perimeter protection at airports, technology manufacturers still face challenges. Welch refers to "the cost of educating the buyer", adding: "While studies have shown that radar and thermal cameras can provide much greater situational awareness at approximately 60 per cent lower cost (compared to fence sensors), most of the security end-users are not aware of this fact."

Remote installations

A second major challenge is to push the technological boundaries. "Logistics for remote installations (such as power, infrastructure, or fibre speed) will continue to evolve, requiring new, self-deployable technologies embedded in security products," predicts Welch. "Communications protocols will continue to expand."

Range is one such boundary. Analysis from the FAS claims that FMCW systems "are not suitable for long-range detection, because the continuous power level they transmit at must be considerably lower than the peak power of a pulsed system", but ICx has developed the STS 1400 - a radar with immediate tracking capability, consisting of a one-second sweep covering 1,400 m with 360-degree surveillance. The STS 1400 is also deployed at Dallas.

Orders are pending for a new radar designated the STS 4400, which Welch says will cover 2.7 miles (4.3 km) in all directions with a one-second sweep, and also features a built-in tracking capability. "This product will be available in the June/July 2008 timeframe and is already pre-ordered for several perimeter security applications including US airports," Welch tells Jane's .

ICx has also developed a software integration product called Cameleon Tactical, which has been ordered for an undisclosed European airport. Cameleon Tactical will integrate six ICx STS 1400 radars, two ICx MDAS trailer units, 80 CCTV devices, a GPS system, gate control, access control, ICx PureActiv Analytics monitoring, 36 cameras, and a variety of fence sensors. Says Welch: "This will be a fully integrated security system communicating data continuously back to a centralised security management facility."

ICx radars are claimed to be the only such systems to pass comprehensive US Air Force (USAF) false-alarm testing that stipulates no more than three false alarms per day may be tolerated.

"Over 700 radars (including the ICx radars) were tested by the USAF 24/7 for a period of 5 months, and the ICx radars were proven to only have an average of 1.87 false alarms per day," Welch says. "No other competing radar passed the test. This resulted in ICx radars being installed in more than 192 USAF bases worldwide."