Stand-Off Surveillance

The security screening of people can be broadly categorised into ‘portal screening’ or ‘surveillance’. Interest in the latter is growing rapidly with increased awareness of the need to identify any potential threat in a standoff situation before it gets too close, or before it enters a secure area. Future surveillance systems will be a fusion of two or more screening technologies with products already on offer that fuse some combination of video, infrared and biometrics in order to identify and track potentially dangerous people.

The introduction of active millimetre-wave screening will greatly increase the intelligence and capability of surveillance systems.

• It can be fused with video cameras to identify threat objects hidden under a subject’s clothing at standoff distances of up to 25 metres.
• It can be fused with infrared cameras to identify threat objects carried by people moving around in the dark.


Tadar Stand-Off Surveillance (SOS)
The TADAR SOS system consists of the standard TADAR scanning mechanism configured with 77 GHz FMCW (frequency modulated continuous wave) transceivers. These low-power, high-bandwidth transceivers illuminate the scene with 4 mm wavelength energy and measure both the intensity and flight path length of the reflected signal. In operation, a small horizontal array of transceivers is vertically scanned at near-real-time refresh rates, producing a narrow mm-wave window, as shown in the figure below. This window can be panned across a wider visual field-of-view, allowing the operator to track a suspect as they move. The mm-wave window is fused to the visual view, which is obtained from a digital camera.

When a threat object is hidden under a person’s clothing, the in tensity of the mm-wave signal increases as the location is scanned. This appears as a ‘hot spot’ superimposed on the visual image.