Event driven persistent sensing: Overcoming the energy and lifetime limitations in unattended wireless sensors

The DARPA Near Zero Power RF and Sensor Operations (N-ZERO) program seeks to overcome the power limitations of persistent sensing by developing wireless, event-driven sensing capabilities that allow physical, electromagnetic and other sensors to remain dormant - effectively asleep yet aware - until an event of interest awakens them. State-of-the-art sensors use active electronics to monitor the environment for such external triggers. The power consumed by these electronic circuits limits the sensor lifetime to durations of weeks to months. In contrast, N-ZERO seeks to exploit the energy in signal signatures to detect and recognize attention-worthy events, such as the presence of a particular machinery type or radio communications protocol, while rejecting noise and interference. This paper will discuss the new architectural approaches and component technologies being developed under the N-ZERO program, which are predicted to extend the lifetime of wireless sensors to several years under many operational scenarios.