The contactless control of persons and the remote surveillance of sensitive infrastructures are important tasks in order to
provide the required security measures to protect the human population against the threads of international terrorism.
Passive microwave imaging allows a daytime independent observation and examination of objects and persons under
nearly all adverse ambient conditions without artificial exposure, hence fully avoiding health risks. The penetration
capability of microwaves provides the detection of objects through atmospheric obstacles like bad weather, fog or dust,
vapour and smoke, as well as through thin non-metallic materials and clothing. For the latter the detection of hidden
objects like weapons, explosives, and contraband is possible by monitoring dielectric anomalies.
The experiment "Common Shield" is part of a perennial investigation series leaded by the "Center for Transformation of
the German armed forces (Bundeswehr)". In 2008 the protection of soldiers and facilities was experimentally
investigated under the aspect of a networked operational leadership. In this context as well a harbour protection trial was
carried out in August/September 2008 at the naval base Eckernfoerde in Germany. This trial was part of the NATO
CNADs program of work for "Defence Against Terrorism (DAT)" starting in 2003, and Germany is the lead nation for
item 7 on "Technology for Intelligence, Surveillance, Reconnaissance & Target Acquisition of Terrorists (ISRTA)".
One main activity in the Eckernfoerde trial was the simulation of a military entrance control facility by a tent including
various imaging and a chemical sensor suite in order to provide security for a military camp. Besides commercial optical
and infrared cameras various passive millimeter-wave imagers have been used from different German research
institutions. The DLR Microwaves and Radar Institute, Department for Reconnaissance and Security (HR-AS), provided
an imaging radiometer scanner operating at W band. A multitude of situations have been simulated and many persons
carrying hidden objects under their clothing have been scanned. The ongoing evaluation of the radiometer measurements
are shown and discussed in the paper.