The Advance of Sensor Networks and Autonomous Systems

The past five years have seen the emergence of a growing array of autonomous swimming, flying, and rolling vehicles, each highly sensored and capable of real-time communication with processors external to themselves. Practical designs are now commercially available for each of the four primary areas of our environment: terrestrial, marine (subsea, surface, and amphibian), atmospheric (gravity constrained), and space (orbital and planetary).

A look at a selection of these achievements in networked sensor systems will set the stage to discuss the communications layer of the ubiquitous computing stack.


The Advance of Sensor Networks and Autonomous Systems

Both sensors and embedded processors are becoming increasingly more capable and less costly, requiring lower power and occupying smaller footprints. More significantly, the means and bandwidth available for information exchange between sensors and processors continues to grow, and costs are decreasing here also.

Together, these advances are the technological foundation for a reality in which high-quality, quantitive responses to an ever-changing environment can be made in real-time by a networked collection of autonomous, decision-making nodes (hardware and software). And these nodes are not only for fixed position sensing.

Autonomous Mobile Platforms: Swimming, Flying, and Rolling

The past five years have seen the emergence of a growing array of autonomous swimming, flying, and rolling vehicles, each highly sensored and capable of real-time communication with processors external to themselves. Practical designs are now commercially available for each of the four primary areas of our environment: terrestrial, marine (subsea, surface, and amphibian), atmospheric (gravity constrained), and space (orbital and planetary).

These designs come in a wide variety of configurations and sizes, from ultra-portable to those capable of carrying large payloads. But regardless of size, all are fully loaded with sensors, on-board imaging or vision systems, ranging and navigation systems, and networked communications. There are autonomous sea surface craft, autonomous subsea gliders, autonomous aerial drones, and autonomous tracked and wheeled vehicles.

The technological future that is unfolding is one of networked sensors, embedded processing (ubiquitous computing), and sophisticated, adaptive systems that are able to monitor their environment using a fusion of sensors and, when the conditions are deemed right by their on-board software programs, to adapt or intervene. Networked, self-powered subsea and surface craft are capable of performing unmanned precision missions. “Drive-by-wire” land vehicles with sophisticated decision processing software can safely navigate a recreated urban environment, obeying all traffic laws. Hand-launched aerial drones are capable of autonomous surveillance missions. These and similar systems have been engineered, seemingly out of the pages of science fiction, and are presently deployed in field sites of the offshore oil and gas, military defense, space, and automotive sectors.

These and similar systems have been engineered, seemingly out of the pages of science fiction, and are presently deployed in field sites of the offshore oil and gas, military defense, space, and automotive sectors.

A Selection of Achievements

A look at a selection of these achievements in networked sensor systems will set the stage to discuss the communications layer of the ubiquitous computing stack.

  1. DARPA’s Urban Grand Challenge of 2007 saw the successful completion of the six-hour built-city challenge by six, fully autonomous “drive-by-wire” unmanned vehicles from Carnegie-Mellon, Stanford, and others. Almost all of the designs incorporated high-definition terrestrial LiDAR communicating via UDP/IP, among a host of their other networked sensors.
  2. iRobot Corporation, the maker of the famous floor-cleaning Roomba autonomous robot, has, over the past decade, been developing and deploying autonomous military robots on track-and-belt platforms for hazardous mission critical operations in Afghanistan and Iraq such as cave exploration, mine-sweeping, IED de-activation. These have in-built orientation sensors, on-board vision systems, ultrasonic proximity sensors, amongst others, all streaming data for on-board processing, mechnical control and adaptive response.
  3. For use in the deep ocean, the Applied Physics Lab of the University of Washington developed the SeaGlider, an autonomous, long-range, ultra-low powered UUV that dives deep and then surfaces, communicating its data via Iridium satellite link, before diving again. (The SeaGlider is now part of the iRobot stable of technologies, as part of a technology transfer agreement in 2009.)
  4. On the surface of the ocean, Liquid Robotics has developed energy-efficient unmanned surface vehicles that are being used to undertake the kind of long-range, leisurely oceanographic observing research that would previously have required an ocean vessel or an anchored ocean buoy. Complete with on-board navigation, telemetry, solar panels, and a wave energy harvesting plaform, the WaveGlider is capable of accurately traveling a pre-defined transect of a thousand miles or more, or staying in place as a “un-anchored” buoy, all the while carrying a payload of oceanographic sensors.
  5. And for the interface between land and sea, in the near-shore surf zone, iRobot has developed the Transphibian, a shallow water mine sweeping autonomous robot.
  6. In the air, Aerovironment has developed back-pack portable, hand-deployable unmanned aerial surveillance drones that have been used to tactical advantage by fighting forces at the front-lines of counter-guerilla combat operations. These ultra-portable micro-UAVs are equipped with low power, high resolution cameras that wirelessly transmit images to the solder’s in-field console for the kind of “over the horizon” look-ahead capability that is pressing back the fog of war.
  7. Finally, in space, the Mars Rover Program of NASA’s Jet Propulsion Laboratory developed the much celebrated twin autonomous rovers Spirit and Opportunity that, after six years since their arrival onto the Red Planet, are still exploring the martian surface and telemetering their data back to earth. These rovers are not only kitted out with a king’s ransom of sensors, but they have on board processing and mission control software modules that allow for adaptive response and on-the-fly adjustment of tactics to suit the particular situation.

Communication Technologies in the Four Primary Environments

What is common to all of these systems, and to the many more applications not mentioned (some listed at the end of this article), is that they require a host of sensors to be integrated into a local-area network on board the system but also the ability to communicate wirelessly with other devices across a wider geographical area.

The examples have been chosen specifically to show that sensored and networking technologies are not limited to particular environments. They can be developed for each of the four principal environments: subsea marine, rugged or urban terrestrial, gravity-constrained atmosphere, and gravity-free and/or atmosphere-free space.

Given the widely varying physics in each of the four disparate environments mentioned above, and given the fact that no single communication technology can operate across all of these different environments, it is worth discussing the background to digital communication in general and wireless telemetry in particular, before turning to the details of particular communications protocols and how to use them.


Stay tuned for the next article on Communications in Sensor Networks.

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2 comments to The Advance of Sensor Networks and Autonomous Systems

  • Can the industry even solve these issues by 2020? Google recently convinced the Nevada legislature to allow driverless vehicles, but the industry will have to go state by state and get federal approval from the DOT and ICC as well. That doesn’t seem like an 8 year project.

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