Detection and discrimination of live and inanimate radar targets through building walls holds great utility for public safety and disaster relief agencies.  Numerous through-wall life detection schemes have been developed in recent years, but their utility has been dampened by excessive cost.  The 2004 Indian Ocean tsunami and 2008 earthquake in China are prime examples of widespread disasters where the ability to quickly determine if living humans were trapped behind building rubble might have saved numerous lives.  A low cost through-obstruction life detection device may have saved countless people who survived the initial disaster, only to succumb after days trapped beneath rubble.

The Naval Research Laboratory sponsored design team developed a proof-of-concept radar system with the ability to detect movement through walls or other obstructions.  The radar system uses a National Instruments CompactRIO chassis for data acquisition and signal processing.  The design team investigated a key problem with portable through-wall radars; namely, receive sensitivity loss due to self-interference inherent in compact linear FMCW (frequency modulated continuous wave) radars.  Loss of sensitivity means the radar cannot "see" as deeply through obstructions or detect smaller targets due to self-interference.  Low-cost embedded microprocessors and microwave devices available as COTS items enable these interference-cancelling abilities.  The final product from the design team is a compact through-wall radar system using a laptop PC for near real-time display of the one-dimensional target data.

http://www.egr.msu.edu/classes/ece480/goodman/fall08/group04/