The US Defense Advanced Research Projects Agency (DARPA) is set to test next-generation sensors for detecting chemical threats through its SIGMA+ initiative.

Beginning in 2014, DARPA’s SIGMA programme has demonstrated a city-scale capability to detect radiological and nuclear threats, and it is now being operationally deployed.

It aims to expand SIGMA’s advance capability for detecting illicit radioactive and nuclear materials by developing new sensors and networks.

The SIGMA+ initiative is focused on providing city- to region-scale detection capabilities across the full chemical, biological, radiological, nuclear, as well as explosive threat space.

Last year, the agency initiated a SIGMA+ pilot study called ChemSIGMA to provide initial data and insights into the way new chemical sensors would function with the help of the existing SIGMA network.

As part of this study, DARPA researchers from MIT Lincoln Laboratory, Physical Sciences, and Two Six Labs, built a small network of chemical sensor packages.

Using the chemical sensor network and the data collected during the events, the team was able to assess the performance of the sensors and network algorithms.

DARPA Defense Sciences Office programme manager Anne Fischer said: “The algorithms were developed using a custom simulation engine that fuses multiple detector inputs. We built the algorithms based on simulant releases in a large metropolitan area – so we took existing data to build the algorithms for this network framework.

“With this network, we’re able to use just the chemical sensor outputs and wind measurements to look at chemical threat dynamics in real time.”

“With this network, we’re able to use just the chemical sensor outputs and wind measurements to look at chemical threat dynamics in real time, how those chemical threats evolve over time, and threat concentration as it might move throughout an area.”

In April 2018, DARPA’s performer teams partnered with the Indianapolis Metropolitan Police Department, Indianapolis Motor Speedway, and the Marion County Health Department to deploy the network on-site at the Indianapolis Motor Speedway.

DARPA researchers could also collect a large relevant data set and user feedback that will assist ongoing system development efforts.

At present, the agency is advancing additional sensor modalities, including short-range point sensors to extend the capabilities for networked chemical detection.

Fischer added: “We’re looking at how we might make this network more robust and more mature.”

“For example, we implemented a network at Dugway Proving Ground as part of a DoD test for simulant releases, and have shown that the network can respond to a number of chemical simulant threats different than those used in Indianapolis, as well as built-in capabilities for mobile releases.”

These systems will further be developed and integrated into the SIGMA+ continuous, real-time, and scalable network architecture to increase the capabilities of the system to monitor chemical and explosive threats.