Testing of victim detection radars has traditionally used human subjects who volunteer to be buried in, or climb into a space within, a rubble pile. This is not only uncomfortable, but can be hazardous or impractical when typical disaster scenarios are considered, including fire, mud, or liquid waste. Human subjects are also inconsistent from day to day (i.e., they do not have the same radar properties), so quantitative performance testing is difficult. Finally, testing a multiple-victim scenario is difficult and expensive because of the need for multiple human subjects who must all be coordinated.

The Victim Simulation System (“Bob”) uses two air-filled bladders sandwiched inside two bags full of a dielectric medium that replicates the properties of humans, within a modified wetsuit to serve as a “skin.” An Arduino microcontroller with high-current drivers controls solenoid valves that fill and drain the bladders to simulate human breathing and heartbeat.

The solution is an anthropomorphic dummy with dielectric properties that replicate those of a human, and that has motions comparable to human motions for breathing and heartbeat. Two airfilled bladders filled and drained by solenoid valves provide the underlying motion for vinyl bags filled with a dielectric gel with realistic properties. The entire assembly is contained within a neoprene wetsuit serving as a “skin.” The solenoids are controlled by a microcontroller, which can generate a variety of heart and breathing patterns, as well as being reprogrammable for more complex activities.

Previous electromagnetic simulators or RF phantoms have been oriented towards assessing RF safety, e.g., the measurement of specific absorption rate (SAR) from a cell phone signal, or to provide a calibration target for diagnostic techniques (e.g., MRI). They are optimized for precise dielectric performance, and are typically rigid and immovable. This device is movable and “positionable,” and has motion that replicates the small-scale motion of humans. It is soft (much as human tissue is) and has programmable motions.

This device provides a way to characterize the performance of victim detecting radars objectively and quantitatively. It dramatically reduces the cost of testing in multiple-victim scenarios. The programmable victim simulator can be used to assess the sensitivity of the radar accurately, and can be placed for long periods of time in environments that would be unsafe for a human subject (e.g., buried for 24 to 48 hours in flowing mud, or within a burning building).

This work was done by James P. Lux and Salman Haque of Caltech; Anthony Vong of Columbus; and James Gill, Anand Gowda, and Susan Milliken of Reel EFX, Inc. for NASA’s Jet Propulsion Laboratory. NPO-48793

This Brief includes a Technical Support Package (TSP).
Victim Simulator for Victim Detection Radar

(reference NPO-48793) is currently available for download from the TSP library.

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This article first appeared in the September, 2013 issue of NASA Tech Briefs Magazine.

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