Security forces require effective ground ISR technologies that can overcome these challenges and provide effective situational awareness. One of the technologies useful in such situations is through-wall imaging which apply radio frequency (RF) and other sensing modes to penetrate wall materials and optimally estimate the terrorists hiding in other rooms and buildings and their activities.
Radars work on the principle of bouncing a signal off an object and measuring the delay in the signal’s return. These signals are analyzed to identify the object — even reconstruct a crude image of it — or determine where it is or how fast it is moving. An extension of this technology is a through-the-wall radar (TWR), which works on the principle that radio waves can penetrate walls, when light cannot.
The Handheld Through Wall Imaging Radar (HH-TWIR) is an important sensor used for detection and location of static and moving targets, especially human beings behind walls. The radar can image in real time the scenario behind wall, identify the number of people and their location behind walls, study their activity patterns and thus helps in identifying the hostage scenario behind the wall. The different types of walls include concrete, reinforced
concrete, brick, cement, wood, stone etc. Imaging the scenario behind wall, tracking the path of the moving targets and presenting fine Doppler information like heart beat and breathing of a person are the important functions of this radar. Low power consumption, light weight, ease of operation are the key features of the system.
US security forces have long been using see through the walls systems like RANGE-R system that can register motion inside closed spaces. The radar system’s high sensitivity is even able to detect a hiding man’s breathing somewhere deep inside a building, behind several walls. These systems have been used in FBI hostage-rescue missions, by firefighters during collapsed building search-and-rescue operations, in the U.S. Marshals Service operations when catching fugitives, and so on.
Indisustry has been able to miniaturize the radar subsystems on a single chip so that Trough the wall imaging or Wall-penetrating radar can be put on handheld devices or Android smartphones. Vayyar Imaging, a 3D-imaging sensor company based in Israel has developed a new 3D-imaging sensor for Android smartphones that allows your device to peer right through walls revealing everything from structural foundations to pipes, to wiring, and even unwanted pests hiding between rooms.
See Through Walls with Your smartphone using 3D sensor
Walabot has developed a new 3D-imaging sensor for Android smartphones “Walabot makes highly sophisticated imaging technology approachable, affordable and usable for everyone,” said Raviv Melamed, CEO and co-founder of Vayyar Imaging, a 3D-imaging sensor company based in Israel. The Walabot DIY is now on sale in the U.S. for the limited special price of $200 (which is later expected to rise to $300)
“Walabot instantly turns a smartphone into a powerful 3D-imaging system at your fingertips,” company officials said. “Our advanced technology lets people see all kinds of things hidden in the world around them, adding yet another dimension to the way people use smart devices today,” they said. Walabot DIY says it can see up to four inches deep into walls made of drywall or even cement.
While the Walabot DIY is more expensive than Walabot Maker version, it could prove the usefulness of Vayyar’s 3D imaging technology. It also gives makers and inventors around the world the opportunity to develop content that takes advantage of the 3D imaging sensor technology. One can not only make use of the existing apps, but can also create their own apps.
The Walabot DIY uses sophisticated algorithms to detect the radio emissions and reflections of different objects. It studies the data to figure out in real-time what kind of object is hiding behind a typical wall. You can use it to see through tables as well, but not metal objects and other types of barricades.
It can help the blind avoid obstacles, sense — and alert you — if your mother or father has fallen in the shower, help your robot become autonomous, and much more,” Melamed said. “The idea is to take the guesswork out of remodeling,” said Melamed, in an interview with VentureBeat. “You don’t want someone punching a hole in your sewer pipes by accident. It’s like real Superman vision.”
According to Melamed, Vayyar’s devices can tell you a lot more about what’s behind a wall. In a demonstration shown to VentureBeat, one can see what’s behind the wall on the screen of the smartphone by just pairing it with the Android smartphone and activating the app. The data is presented in a raw form or an analysis of that data as calculated by Vayyar.
As there are some interruptions in displaying what is behind a piece of a wall, you have to move it over the wall slowly. However, you can get a 3D image of an entire room’s walls in just few minutes. Melamed said it will make it a lot simpler to locate a leak in a pipe, or just drill into a wall without the fear of hitting a pipe or electrical wire, hang pictures in a gallery, or mount shelves.
“We can get it to 5 millimeters accuracy,” Melamed said. “You’ll know what’s inside a wall in a few minutes.” Walabot DIY also features a flexible sensitivity setting for optimal standardizations on particular renovation and construction projects. This offers two sensing modes and can effortlessly snap photo screenshots for use in offline analysis.
Melamed also demonstrated how Walabot DIY can identify the pattern of your breathing. In other words, it has applications for examining your sleep patterns and other uses in health, safety, and quality of life. While the technology is still in its initial stages, it could shoot more demand for augmented reality applications, he said.
IISc’s Radar imaging chip can see through walls
A through-the-wall radar, built on a chip smaller than a grain of rice, has been developed by a team of researchers at the Indian Institute of Science (IISc), led by Gaurab Banerjee, Associate Professor at the Department of Electrical Communication Engineering.
Developed using Complementary Metal Oxide Semiconductor (CMOS) technology, this radar has a single transmitter, three receivers, and an advanced frequency synthesizer capable of generating complex radar signals, all packed together into a tiny chip. Its small size can enable mass production at a low cost. Such radars can have wide-ranging applications in the defence sector, as well as areas such as healthcare, transportation and agriculture. “Only a handful of countries in the world today have the ability to put the entire electronics of a radar on a chip,” says Banerjee.
“TWR imaging has always been one of the most challenging radar design problems,” says Gaurab Banerjee
Associate Professor, Department of Electrical Communication Engineering, Indian Institute of Science (IISc). For one, the signal can get significantly damped while passing through walls. To overcome this, radio waves consisting of a large number of frequencies need to be used, which can complicate the design. These radars also use a more complex signal, known as a chirp, which requires customized electronics such as a microwave transmitter, a receiver and a frequency synthesizer.
With their design, the IISc team has now managed to squeeze all of these electronic components into a single, tiny chip. They used new architectural and circuit design techniques to overcome challenges specific to radars – such as the design of a wide fractional bandwidth transceiver. “The same design techniques that have enabled smaller and cheaper smartphones can now be used to miniaturize the complex electronics of a radar system into a small chip,” says Banerjee. Although the chip was originally developed for airport security-related applications, Banerjee’s group is also exploring applications in other areas such as healthcare.
For instance, it can be used to monitor the health of elderly people. There are more than 10 crore elderly people in India, with many living on their own. If they slip and fall, and it goes undetected, it can lead to severe long-term problems. Although cameras and wearables have been used to monitor their movements, there are concerns about privacy and inconvenience. TWR radar systems, therefore, offer a convenient alternative.
“It might be possible for a centrally-placed TWR system to scan the house, and construct a model of when a person is standing or sitting down. If there is a sudden change in gait due to a fall, it can trigger an alarm,” says Banerjee. “It could also monitor breathing and respiration rates and assess the severity of a fall.”
This research was funded by the IMPRINT programme of the Government of India, with additional financial contributions from the Ministry of Human Resource Development (MHRD) and the Defence Research and Development Organization (DRDO). Bharat Electronics Limited (BEL), a defence PSU, has been an active industrial partner in this IMPRINT project since its inception.
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