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Through-the-Wall Surveillance Technologies

NCJ Number
Corrections Today
Date Published
3 pages

This report describes current and emerging technologies to allow correctional and law enforcement officers to detect and track offenders through the walls of buildings.


Correctional and law enforcement officers are often placed in harm’s way because they lack the ability to detect and track offenders through the walls of buildings. The National Institute of Justice’s (NIJ’s) Office of Science and Technology (OS&T), as well as other private and public agencies, have made the development of through-the-wall surveillance (TWS) technologies a top priority. An array of TWS technologies are emerging, ranging from relatively simple low-power, radar-based devices designed for individual officer use to more complex technologies designed for SWAT operations. These devices are described, followed by a discussion of emerging non-radar based TWS devices based on magnetic sensor technology and ultrasound technology, which may enable officers to identify offenders through metal walls. The report also identifies other devices that are in various stages of development, including TWS tagging technology that would allow officers to separate offenders from officers. Exhibits

Date Published: January 1, 2001