GCN LAB IMPRESSIONS
MIT team's radar array can see through walls, for real
- By Greg Crowe
- Oct 27, 2011
When radar was first developed, it was heralded as a wonder that could do anything. Need to file your back taxes? Radar. Need to save a roast? Radar. Need to find the position and velocity of an aircraft that’s miles away? Well, that one actually is radar, but you get the idea.
This miracle technology didn’t even lose its super powers in films such as “Radar Secret Service,” whose reference my boss, Lab Director John Breeden II, insisted I include in this article.
But in reality, a basic radar setup works pretty much the same way as our regular mortal human eyes do. Electromagnetic energy of some wavelength bounces off an object and back into the receiver, at which point the image is processed. The only difference is that radar devices work in a different frequency than visible light – down in the microwave/radio end of the spectrum.
And since the vast majority of these electromagnetic waves — 99.4 percent — are blocked by solid matter, radar generally has as much trouble seeing through walls as our eyes do.
Now, researchers at The Massachusetts Institute of Technology’s Lincoln Laboratory have developed a phased array of radar transmitters and receivers that can emit waves with enough power to go through a concrete wall, bounce off of the target inside, and go back through wall with enough strength left to be detected by the receivers.
Their system also is able to differentiate between the waves that are doing that and the ones that are simply bouncing off of the wall in the first place, making the wall effectively invisible to it.
But that isn’t the impressive part, they claim. In order to get the array to accomplish this, they had to get the system to be able to analyze signals much more quickly and much closer to real time.
Larger-scale conventional radar doesn’t have to update nearly as frequently because the objects tend to be farther away — think of the periodic blips on those low-res flight-control screens in the movies. But at distances of 20 to 60 feet, rapid processing is vital, as the situation inside the wall you are looking though can literally change in the blink of an eye.
Research team members demonstrated the radar at 20 feet, which they said is a practical distance for an urban combat situation, MIT News reported. The system provides a real-time picture of movement behind via a 10.8-frames/sec video in which people would be depicted as red blobs on the screen.
In a video with the MIT News report, researcher Gregory Charvat said their goal is “to aid the urban warfighter, to increase his situational awareness,” but it’s not hard to imagine other uses, such as surveillance or in some kind of standoff/hostage type situation.
Now if we can just get radar to help me file my back taxes, I’ll be set. But either way, this is a huge step forward in a new application of a 70-year-old technology.