An article I wrote for Electronic Products.
A new radar system sends out two radio pulses instead of one to rescue trapped survivors
British engineers have taken inspiration from one of the world’s smartest mammals, the dolphin, to create a new type of radar device that could easily track miners trapped underground or skiers buried in an avalanche.
Similar to a dolphin’s use of echolocation, the radar device sends out two pulses in quick succession to allow for a targeted search for semiconductor devices while canceling any background noise. According to Timothy Leighton of the University of Southampton’s engineering faculty, since the device has more accuracy and speed than conventional radar, it’s been able to detect roadside bombs, bugging devices and mobile phones, even in areas with lots of metal clutter.
Leighton told Discovery that the research was triggered by the curiosity of how dolphins can “see” beyond the clouds of bubbles they blow to herd their prey into smaller groups for feeding.
“I was thinking to myself that dolphins should not be able to see fish with their sonar in these bubble clouds unless they are doing something very clever that manmade sonar cannot,” he said.
By thinking about what kind of pulse he’d send out to locate objects, Leighton thought up a pulse that was positive and negative, and so came the idea for a radar system that can send out pulses in pairs, with the second having the reverse polarity of the first. Unlike ordinary radar that sends out a single radio pulse, when the two new pulses hit rocks, wood or most metals, those same pulses that were sent out—a positive and a negative—return, effectively canceling each other out.
“If it hits a semiconductor device, then it takes that pulse of a negative polarity and turns it into a positive polarity,” Leighton said. “It makes everything positive. They come back very strongly because you’re adding a positive to a positive so you get a very strong signal.”
To test their device, the researchers built a semiconductor tracker that weighed less than two grams and cost less than a euro, and it was easily located by the new device. Considering the price and size of the tracker, the researchers suggested miners and search and rescue workers keep one in their helmets and skiers keep one in their boots. If a person isn’t tagged with a special device, they can still be found using the reverse pair radar, since most people carry a mobile phone. Even if its battery is dead, a phone can still be tracked since the radar only needs semiconducting metals, which are abundant in mobile phones.
After creating their life-saving radar device, Leighton and his colleagues discovered that it actually doesn’t mimic dolphin sonar. Though dolphins do send two consecutive pulses at the same time, which was what originally inspired the team, the signal varies in amplitude, not polarity.
Story via Discovery.