Is radar a better choice for perimeter protection?

Is radar a better choice for perimeter protection?
Both radar and lidar can be used for perimeter protection; however, radar is a more suitable choice for several reasons. Although radar and lidar have 360-degree scanning capabilities, their ranges of detection and detection methods differ. Additionally, the data produced by the hardware differs — while radar can see further, lidar has better image resolution. As a result, their application strengths make them unequal candidates for perimeter security.

“Radar is more suited to wide-area surveillance due to its long detection range. Lidar has a much shorter range due to atmospheric affects and limited power output. Radar and lidar are normally used for the detection of both pedestrian and vehicle intruders but have more recently been adapted for targeting drones,” explained Phil Avery, MD of Navtech Radar.

From a perimeter surveillance perspective, radar is the superior choice between the two technologies — it is often considered more suitable than traditional perimeter security measures, as it allows for detection both inside and outside the perimeter, Avery said. “This gives sites a full understanding of the events taking place within and outside of their compound.”

“Radar has a major advantage over lidar and other perimeter detection technologies due to its ability to operate in adverse weather and light conditions. Radar performance is not affected by any changes in the environment, so it can be used for perimeter detection in harsh environments. Lidar can become heavily affected by dust, sand and fog, causing its performance ability to decrease. It is also affected by heavy rain and snow, which makes it less fitting for outdoor perimeter detection usage expect at short range,” Avery explained.

Another advantage of using radar for large areas is that radar security is less expensive than traditional perimeter security measures such as fences, lights, guards and cameras. “One radar can cover hundreds of square kilometers, is very reliable, works in virtually any weather day and night, and has no recurring costs,” said Bill Drafts, Director of Force Protection and Integrated Solutions Product Marketing for the Government and Defense Business Unit at FLIR Systems.

“As radar has a longer range, fewer sensors are required for the same amount of coverage of a site. The advantage of wide-area surveillance is that it provides operators with advance warning, which allows plenty of time for interception and reduces the likelihood of an actual security breach. Also, sensors continuously track intruders inside the perimeter, meaning operators will know their exact location. Traditional methods are far less precise and are often only capable of detection on the perimeter, with no information once the intruder has moved away from the fence line,” Avery added.

This however, does not mean that radar is a perfect solution. Both radar and lidar technologies are disadvantaged by line of sight; for example, large infrastructure such as buildings or trees could affect the detection performance, as this would be obstructed.

“When installing radars, it is important to make sure the radar has a clear line of sight. Radars cannot see through any object. It is also important to locate radars away from large objects, as they tend to cause high energy reflections that can limit their effectiveness,” Drafts explained. “If the installation must be near a large object, the emission can be masked, meaning as the radar rotates, the beam will turn off when it would have hit the object, eliminating any reflection. Lastly, the radar needs to be installed high enough off the ground to limit multi-path issues. In general, the longer the range needed by the radar, the higher it should be mounted.”

Cameras make a perfect partner to radar

Like radar by itself, cameras alone are not an effective enough solution for perimeter security. That is why radar is best integrated with surveillance cameras to give not just positional information, but also visual information to security teams.

“While cameras provide friend-or-foe identification of the intruder, they can only see the region of interest they are looking at. This becomes even more troubling when the targets are numerous or at greater distances, as the camera must be zoomed in and the field of view is greatly reduced, inhibiting situational awareness. While the camera is identifying the distant intruder, numerous intruders may be entering the monitored zone outside the camera’s field of view,” said Bill Drafts.

On the other hand, radars detect all targets, ranging from sizes as small as commercial drones to as large as cruise ships, without a change in their field of view, Drafts added. “The radar persistently scans 360-degrees every second, looking for any target that reflects the emitted energy back to the radar. The ideal perimeter security solution contains a radar, a camera and command and control software. The radar detects the target, and the command and control software commands the camera to slew to cue to the target for identification of the intruder.”

Avery noted certain radar technology such as Navtech Radar’s AdvanceGuard solution can be integrated with thermal or surveillance cameras, or with a network of sensors for complete coverage of an entire site. The high resolution provided by the company’s solution allows the system to differentiate between targets by using characteristics such as speed, direction and size.


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