Over the last couple of years, I have begun hearing about the increasing use and availability of ground-based radar (GBR) systems applied to area intrusion protection. Recently, Terry Harless, a senior security consultant with 1898 & Co. (a recently formed entity within Burns and McDonnell), piqued my interest, so I decided to take a deeper look.
GBR systems use microwave energy; however, do not confuse that with microwave sensors. There are many microwave-based sensors designed for internal intrusion protection and certain outdoor systems, but outdoor system applications are best suited to perimeters and fence lines.
Radar brings to mind weather forecasts and aircraft control – just as these radars provide area scans, so do GBRs. “These systems work best in large unobstructed areas, such as open fields, and they are a good solution for night-time use and where fog and rain are of concern,” Harless says. “IR thermal camera back-up adds to system effectiveness.”
Radar systems work on reflected energy, and areas normally contain various elements that reflect energy back towards the radar. In the steady state, this is known as “clutter.” An individual sweep of the radar may yield a reflection that stands apart from the clutter, which may be something of interest when seen on multiple consecutive sweeps.
Radar units are placed to detect a person or object moving radially toward or away from the sensor, triggering a change in frequency – known as the Doppler effect – and the primary basis for detection. Potential targets in motion tangentially (maintaining constant distance from the radar) or slow-moving objects may compete with high clutter levels and render detection more difficult.
Adding to system effectiveness is the integration of analytics into the system. Direction of motion rules will determine if a person or object is moving toward the sensor, allowing the system to alarm only upon motion vectors of interest. Stopped or slowing down vehicles may also be reasons to alarm. Discrimination between animals and humans or vehicles and humans further helps reduce false alarms.
“In the past two years, we are seeing huge increase in demand for GBR,” says Yaron Zussman, General Manager of radar supplier Magos Systems. “Both end-users and consultants have realized that the improvement in sensor technology, radar software and reduction of cost make GBR a viable solution for many different verticals past the traditional defense applications. I expect machine learning and AI to accelerate this trend and to increase usefulness and reliability.”
Harless says his primary application area to date is electrical utility substations, with priority given to critical substations in the transmission network. “300 meters is about the farthest distance someone could shoot and cause damage to critical equipment within a substation, so we set these systems to detect up to 500 meters and in some cases further, depending on the landscape, to allow adequate reaction time,” Harless explains.
Other interesting applications include airports, data centers, prisons, campuses and industrial complexes – all areas with likely large open spaces around them – and drone detection, where timing of deployment remains uncertain due to FAA rules.
Technical and Other Deployment Considerations
An important consideration is FCC licensing. Certain systems work in the ISM band and may be able to operate unlicensed. The resulting advantage of speedy deployment may be offset by the presence of other systems broadcasting in the same band. Licensing may create project delay and add cost but help assure a more favorable signal environment.
Harless sees the closest competing technology being thermal cameras, with a sensing distance crossover point of approximately 100-200m, where GBR provides a cost advantage. However, PTZ cameras – thermal or IR assisted – are normally used in conjunction with GBR to verify the object being detected. A single GBR can cover enormous swaths of land while cameras typically have a narrow angle of view when used for long distances.
“Correct deployment is the key to successful operation,” says Brock Josephson, Physical Security Consultant and a colleague of Harless at 1898 and Co. “It is sometimes difficult to anticipate factors that could decrease performance, such as high levels of reflected power – too much of which can saturate the receiver. When possible, testing onsite, in advance of deployment, can help identify these and other difficult to anticipate issues.”
Key considerations when deploying radar include: avoidance of obstacles and creating blind spots; clear line of sight; positioning to detect radial movement; clutter reduction; and avoidance of reflective objects, such as metal, glass etc.
Choosing a Solution and Partner
For consultants and integrators alike, GBR represents a proven and useful technology that should be in the mix for consideration for wide area sensing, particularly beyond 100 meters. When comparing and choosing products, here are some of the primary comparative factors:
- Vertical and azimuth – think of vertical and horizontal field of view. A higher vertical number provides extra margin for look down from the radar unit. Typical field of view is 100-120 degrees horizontal, and 20-30 degrees vertical, providing the potential to cover hundreds of acres.
- Distance – published distances will vary for vehicles (longest), humans and even drones. GBR systems are advertised with distances up to 13 km for vehicles, 800 meters for humans and 500 meters for drones.
- Range resolution – a measure of location uncertainty.
- Licensed vs. unlicensed.
- Power – emitted power and consumed power.
- PoE operation – potentially simplifying deployment and saving installation cost.
- OEM integrations – operation tightly integrated with video systems increases overall system effectiveness.
Some of the manufacturers in this space to investigate include: Axis Communications (short range, up to 50m, unlicensed – www.axis.com/en-us/products/axis-d2050-ve); Magos (humans up to 800m, unlicensed, PoE – http://magossystems.com); SpotterRF (humans up to 1,400m – http://spotterrf.com); and OWL (humans up to 8 km – http://owlknows.com).
Ray Coulombe is Founder and Managing Director of SecuritySpecifiers and the CONSULT Technical Security Symposium. Reach him at [email protected], through LinkedIn at www.linkedin.com/in/raycoulombe or follow him on Twitter, @RayCoulombe.