Look through the walls with Wi-Fi waves

British engineers at University College London have studied a passive radar system that allows them to see through walls using Wi-Fi signals generated by wireless routers and points. come.

The system was developed by engineers Karl Woodbridge and Kevin Chetty. The system consists of two antennas and a signal processing device (computer) with no more than one suitcase size.

Unlike conventional radar, which emits radio waves and then measures reflected signals, it is impossible to detect the radar system when it is operating.

The new device will be very useful in reconnaissance before the battle.

The working principle of passive radar is relatively simple. Wherever you have Wi-Fi, you can also broadcast radio waves at 2.4GHz and 5GHz. When these waves collide with a moving object, its frequency changes (the Doppler effect).

This phenomenon prompted Woodbridge and Chetty to recreate the image of any object or person moving on the other side of the wall.

Essentially, this is a radar system that captures waves generated by external Wi-Fi routers that automatically generate waves.

During the test, these passive radar systems could determine someone's location, speed and direction of travel on the other side of a 30cm thick brick wall. The only problem with Doppler-based systems is that they only detect a moving object.

Therefore, this radar system does not detect a thief or a fake warrior while standing still. But engineers say that after they have improved and perfected, it is possible to increase the sensitivity of the device they devise, even allowing for the detection of very small movements such as the oscillations of the bones. The ribs breathe in and out.

The purpose of this 'look through the wall' device is as described, which can be seen primarily to be used in the military. The UK Department of Defense investigated the possibility of applying passive radar to scouting when a battle took place in the city.

They can also be used to monitor the activity of children and older adults in need of care in the home. Increasing the sensitivity and precision of the device (with multiple routers pointing to each side) can produce video with a radius.