How does a radar work?
Radar systems work by emitting short pulses of signal (Radio Frequency waves). If there is an object in the way of the signal, the echoes or reflections of the signal are captured by the radar antenna and amplified to identify the nature of the object. Radars continuously scan the sky looking for reflections and changes to detect movement and size. Reflected signals can be compared to a database for object characterization.
Radar technology has served us great for locating manned, larger, or long-distance aircraft flying within traditional airspaces. These aircrafts have a big RCS (radar cross section). But with commercial drones having an RCS the size of a bird, high resolution radars need to be specifically designed for drone detection.
What is a Radar Cross Section (RCS)?
Radar Cross Section (RCS) is a measure of how detectable an object is by radar. The signal sent by the radar is reflected off the surface of the detected object, and captured by the radar receiver. The more of the signal that is reflected back from the object, the more accurately a radar can detect an object. The reflectability of an object is determined by several factors, the most important of which are size of the drone and the amount of reflective materials and components. Usually radar signals pass through materials like plastic, but are reflected off materials like metals. In the case of commercial drones, the RCS is low as the only reflective components are the batteries and motors of the blades.
Can a radar detect a drone?
Yes, High-resolution radars are specifically designed for drone detection and tracking. Reflected signals are analyzed and compared to a database for drone characterization. The stored signatures can also be used to eliminate objects that are not drone-like much like how radars are used to detect birds. This signal processing greatly improves detection performance and allows for fewer false positives. Advanced technologies like Machine Learning and AI, can further improve radar detection of drones and decrease the number of false positives.
Radar can also provide real-time tracking by providing the GPS location of the drone detected. THe GPS location is calculated based on the GPS location of radar sensor, and distance and angle at which object is detected from the radar sensor.
How far can a radar detect a drone?
The range for each drone threat will vary based on the RCS. Radar can detect drones with a larger RCS at a greater distance that a drone with a small RCS. Typically, radar systems can detect drones up to 1 mile away for a Phantom 4 Size drone. The range is affected by Drone size. Radar detection range is also slightly affected by weather conditions like rain and fog.
Can a radar detect all types of drones?
Yes, radar can detect all types of drones regardless of whether it uses RF communication, GPS preprogramming or Wifi/Cellular communication. The only limit to radar detection is the size of the drone. A radar won’t be able to detect very small toy drones, but these drones won’t pose a significant threat since they can’t carry a payload.
Does a radar give false positive while detecting drones?
Yes, a radar can give a false positive while detecting drones. Initially a radar does not know whether an object is a drone. The reflections from the objects captured by the radar receiver is compared with a database of drone signatures and if the signatures match then the object is classified as a drone. There can be instances where an object with a RCS that seems like a drone is detected and categorized as a drone, when it might actually be something else.
For this reason, it is important to layer radar drone detection with RF & Visual detection, so that security teams can confirm whether an alert is a real threat or a false positive.
Will one radar sensor give full visibility and detect all drones in an area?
It depends on each radar sensor. Some sensors only have a 90 degree field of vision, some have 120 degrees field of vision. Some radar systems are set up to rotate where they analyze the environment in 90 degree angles but achieve 360 degree coverage by rotating and sending signals in all directions.
Our Airspace Security experts recommend using RF sensors for broad 360 coverage, and then layering the RF sensor with a radar system over critical areas.
How many radars do I need to cover my area?
Radars are expensive compared to RF sensors, and have some limitations like field of view, and the range of detection. To achieve complete 360 degree detection coverage using only radar sensors is expensive. For this reason, radars are best used as an additional layer over a critical area, along with RF sensors and Visual detection for a cost-effective and complete drone detection solution.
911 Security helps you conduct through reviews of your environment, and can propose the best configuration of where to use a radar to achieve the best security system to match your budget. Schedule a call with one of our Airspace Security experts to get started.
How can I view, track and get alerted to a drone detected by a radar?
A radar sensor is often accompanied by it’s software that allows security teams to monitor all the drones detected by the sensor. However, using different softwares for different sensors can be confusing, and increases time to identify, validate and respond to threats.
911 Security’s Drone Detection Software Platform called AirGuard, integrates data from radar and all other detection systems, into one user interface, so you can quickly assess and respond to any aerial drone threats.