Earlier SIGMA demonstrations conducted in New York and New Jersey used 100 sensors. For the most recent Washington DC test a thousand volunteers were equipped with smartphone-sized radiation detectors and sent out on a mission at the National Mall, the central urban park of the US capitol.
The ‘hunters,' wearing backpacks containing detectors, were given a fictional scenario involving the foiling of a terrorist plot by saving a geneticist kidnapped by masked men. The agency intended to determine how effective the sensors could act as nodes of a mobile network over an area of five square miles (13 km2) and to use the aggregated data to upgrade algorithms for the final version of SIGMA.
"The SIGMA system performed very well, and we collected and analyzed a huge amount of streaming data as we watched in real-time as participants covered a large portion of DC," said Vincent Tang, DARPA program manager, cited by New Atlas.
"The data collected is already proving invaluable for further development of the system, and we're excited that SIGMA is on track to provide US cities an enhanced layer of defense against radiological and nuclear threats."
The detector network is expected to be operational by 2018, upon the completion of final wide-area monitoring-capability tests.v
