DARPA Persistent Aquatic Living Sensors (PALS) Proposers Day

Persistent Aquatic Living Sensors Program Overview

Despite advances in sensor systems for submarine and underwater vehicle monitoring, spatial and temporal coverage of maritime environments still suffers from numerous gaps. In particular, due to a combination of high manpower requirements, lack of persistence, the need for short endurance or ship/shore-based power sources, and the often noisy or cluttered environments,  current maritime procedures often employ sensor suites at the tactical level to protect high value assets, rather than at the strategic level, to maintain overall situational awareness. Furthermore, smaller targets, in particular unmanned underwater vehicles, are exceedingly difficult to detect using current active or passive sonar technologies from any meaningful standoff distance.

Marine organisms—or natural ‘sensors’—shaped by millions of years of evolution, abound in the world’s oceans. The sensory and behavioral characteristics of these biological organisms are routinely overlooked, often treated as noise by man-made sensor users. For example, sonar operators often complain about the strong signals of snapping shrimp in reef environments, disrupting their ability to listen for targets of interest. Biological sensors occupy every maritime environment, and have evolved multi-modal sensing capabilities across many domains—electrical, acoustic, optical (including in extremely low light), magnetic, chemical, and even tactile, in the form of mechanoreceptors capable of detecting and triangulating minute changes in fluid flow as well as sources of disturbances.

The PALS program aims to leverage the biological maritime ecosystem across a wide array of marine environments, particularly in the shallow-coastal and littoral regions, to find M/UUV targets. It aims to transform existing biology, historically characterized as background noise, into highly content-rich biological signals that can be interpreted to track, classify, and report on the presence of M/UUVs. Performers on the PALS program may consider organisms from bacteria through macro-organisms as well as multi-organism interactions, and will:

  1. Characterize the biological signal: engineer and/or reproducibly observe, understand, and model behavioral response of biological organisms to M/UUVs and confounder objects, including discriminations of like-sized objects at multiple scales
  2. Interpret the biological signal: detect observed unique biological signals and translate these into actionable alert information

The PALS effort requires two stages of sensing. In the first, the biological organisms sense the intrusion of an M/UUV or confounder into their environment and respond with an output signal or observable behavior. In the second stage, a man-made detector system captures and interprets the unique biological signal or behavior generated by the organism(s), making an analyzed result available in the form of distilled alerts. These components will be integrated into demonstrator systems able to be deployed in a maritime environment, and capable of end-to-end system performance through delivery of alerts via commercial satellite link. Ultimately, PALS systems will offer long-endurance, widespread sensory coverage in multiple maritime environments, augmenting and enhancing current detection capabilities.