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Radar technology is finding a host of new uses outside of the military
Imagine trying to land a huge plane on a short runway, in complete darkness and immersed in thick fog. Airline pilots do this regularly, using radar (radio detection and ranging) to guide them. Today, radar has a wide variety of uses, from weather forecasting to guiding autonomous vehicles. So, how exactly does radar work?
How radar technology works: Radar works by sending out radio waves and ‘listening’ for the reflection of that beam from any nearby objects. Radio waves are similar to light waves, but they are much longer and have much lower frequencies. Radio waves used in radar have wavelengths ranging between a few centimetres and 1 metre.
Both radio waves and light waves are part of the electromagnetic spectrum. This means that they are made up of electrical and magnetic energy patterns.
In a radar, a device called a magnetron produces radio waves, and an antenna sends the waves out over a large area. The waves travel at the speed of light. When they hit something, some of the waves bounce back toward the antenna, which detects the returning waves.
Because the speed of the waves is a constant, measuring the time it takes them to return can determine how far away the object is. Receiving equipment filters out useless reflections, such as those from the ground, or buildings, and displays the significant reflections on a screen.
How radar technology is used: Practical radar systems were originally developed during World War II as a way to detect incoming enemy aircraft and missiles, and radar is still used for this purpose. Most airplanes and large ships also use radar to aid in navigation, and air traffic controllers use radar to guide landing planes.
Another use is one that may have cost you some cash: speed guns. These are actually based on a slightly different technology, called Doppler radar. The speed guns measure the changes in the frequency of radio waves as they bounce off speeding cars. These changes are used to determine the speed of the object. Doppler radar is also used in weather forecasting, determining how fast weather systems are moving.
Radar has been used in cars for around 20 years, in applications like cruise control and anti-collision systems. It is also now being used in autonomous vehicles, although it is not precise enough to be used without other detecting systems.
What’s next for radar technology: Several companies are working on developing more accurate radar for use in cars. Startup Wavesense has adapted radar for use in autonomous vehicles, especially in navigating through poor weather conditions. And in Australia, researchers at Volvo are developed a kangaroo avoidance system for cars that uses radar and video to spot roadside roos before they can leap in front of the vehicle.
Bicyclists are not left out, either. South African company Backtracker is developing a radar system that can alert cyclists to oncoming vehicles.
Researchers are also experimenting with using radio waves at different frequencies. Engineers in South Africa have recently developed a very small radar that uses lower frequencies to detect objects at close range. This could be useful in helping autonomous vehicles and drones to avoid objects in their path.
And scientists at Tel Aviv University recently created a radar that uses a very narrow range of frequencies, which can produce the same quality of data but at a much lower cost and using far less bandwidth. In the future, when every vehicle may be equipped with radar, and all needing to use the entire bandwidth, innovations like these may also help to reduce “radio traffic jams.”
