• Electronic Kid
  • Useful-news
  • Forum
  • Fellowship
  • E-Library
  • All

Emerging Radar Technology: Real-Time Through-the-Wall Surveillance

Emerging Radar Technology: Real-Time Through-the-Wall Surveillance

Emerging Radar Technology: Real-Time Through-the-Wall Surveillance

Sarath Mohan K.T. 

Imagine hostages being taken by terrorists in a large building with all modes of communication shut-off. Rescuers are ready to deploy, but cannot because they do not know where the hostages are inside the building. They now have to spend a considerable amount of precious time trying to locate the hostages.

But, what if they could see through the walls?

Through-the-wall surveillance (TWS) technology is an emerging technology that allows the user to see through obstacles, such as concrete walls, doors and other visually-opaque materials. Though initially developed for military use, it is now being used by law-enforcement agencies as costs have become more affordable.

What is TWS
There are usually two types of devices that use this technology-portable hand-held devices that alert officers to the presence of an individual behind doors or walls, and portable, computer based devices that can help bigger security teams to visualise events during hostage situations.

Electromagnetic waves within the lower GHz range can penetrate most building materials, allowing for the detection of hidden targets. Every person or object can reflect an electromagnetic wave, which can be registered by the radar receiver. The challenge is to distinguish between wanted (living persons) and unwanted objects (rubble or interiors of a room).

To view Figures along with full article:  Click here

So, how does the device identify the presence of a human if there is no movement? A living being is always connected with some movements, like breathing, even when asleep or stationary. Breathing causes minor variations in the body's shape, which can be determined by the radar.

The radar is able to pinpoint and track people's movement behind a wall in real-time with down-range versus cross-range image of all targets. For recognition of static objects, radar imaging must be performed, which requires scanning and sophisticated data processing.

How TWS works
The radar uses a frequency-modulated continuous wave (FMCW) radar architecture operating at 1-4GHz band, with good range resolution of 5cm due to its high-bandwidth chirp. A narrow-band, spatial-frequency filter provides a range gate that eliminates the wall from the image, facilitating maximum receiver dynamic range to be applied to the target scene behind the wall. A time division multiplexed (TDM), multiple-input multiple-output (MIMO) array provides a low-cost, least-complicated solution to a fully-populated antenna aperture capable of near-field imaging.

To achieve 16-frames-per-second video-frame-rate imaging, a data- pipeline and streamlined imaging algorithm is developed. Coherent frame-to-frame processing rejects stationary clutter, revealing the location of moving targets. Maximum expected range through a solid concrete wall is 20 metres.


Electronics For You, A-001, Garden Mansions, Old Airport Road, Bangalore, India.
Forward this email

This email was sent to dragonkhm1.babe@blogger.com by newsletter@electronicsforu.com |  

EFY Group | A-001, Garden Mansions | Old Airport Road | Bangalore | Karnataka | 560008 | India