This site contains information for the communications working group members.

The leaders of the Communications Working Group are Kate Remley (contact) and Galen Koepke (contact), both the National Institute of Standards and Technology Electromagnetics Division

WK14437  Evaluating the Performance of Radio (Wireless) Communication Links used for the Control and Telemetry Systems on Urban Search and Rescue Robots

1.1. This practice covers the performance evaluation of radio (wireless) communications links used for the control and telemetry systems on Urban Search and Rescue (US&R) robots. These performance metrics include physical range (line-of-sight (LOS), non-line-of-sight (NLOS)), and building/rubble/tunnel penetration, effective data capacity at maximum range, susceptibility to electromagnetic interference, link security, and data logging. This protocol provides a basis for performance comparisons among such systems based on these metrics.

1.2. This protocol establishes requirements and measurement methods for specifying and testing the performance of radio (wireless) links used between the control operator station and the working robot. These links include the command and control channel, video, all sensor data telemetry, and other radio-frequency systems.

1.3. The measurement methods in this document are intended to apply to ground based robots. Test protocols for aerial and aquatic robots are not included in this revision.

1.4. This protocol does not apply to systems connected by a wire or optical cable (tether).

1.5. Actual performance specifications and tests for specific systems (e.g. real-time video, sensors, etc) are given in other documents. The communications criteria (distances, measurement bandwidth, etc.) in this document must be used with the systems documents to determine acceptable performance.

1.6. The measurement methods assume systems that require a clear frequency channel will have that available (see 1.7). Systems that utilize protocols capable of multiplexing and can share a common frequency channel will be tested with some level (to be determined) of other activity on the channel, typical of what would exist during an emergency response.

1.7. Frequency coordination and assignments, and interoperability are not addressed except as noted in 1.6. These issues should be resolved by the affected agencies (Fire, Police, Urban Search and Rescue, etc.) and written into the Standard Operating Procedures (SOPs) that guide the response to emergency situations.

1.8. This protocol also establishes minimum electromagnetic interference and compatibility requirements to control unintentional emissions and insure some level of immunity to other radio-frequency sources operating in the vicinity of the robot and control station.

No such standard exists.

Keywords
communications; radio; wireless; robots; urban search and rescue;

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Conflicting Signals Can Confuse Rescue Robots

Sensor-laden robots capable of vital search and rescue missions at disaster sites are no figment of a science fiction writer's imagination. Prototypes and commercial models of urban search and rescue (US&R) robots will soon begin to work rubble piles across the country. Too many of these lifesaving robots, however, could be too much of a good thing, according to researchers at the National Institute of Standards and Technology (NIST), who report that the radio transmissions of multiple robots can interfere with each other and degrade search and rescue performance.

A NIST analysis of wireless radio field trials for US&R robots, presented at a conference on February 28,* found that 10 out of the 14 robots tested experienced communication problems due to radio interference from other systems. Engineers carried out tests on the robots last August at a US&R robot standards development gathering in Gaithersburg, Md., sponsored by the Department of Homeland Security. The researchers found that neither use of "industrial, scientific, and medical" (ISM) frequency bands nor adherence to protocols designed to minimize interference between systems in the bands could guarantee flawless communication between a robot and its human operator. Radio interference could happen whenever the ISM frequency bands became crowded or when one user had a much higher output power than the others. An example of the latter problem occurred during the tests when transmitters in the 1760 MHz band knocked out video links in the 2.4 GHz frequency band. In another case, a robot using an 802.11b signal in the 2.4 GHz band overwhelmed and cut off a robot that had been transmitting an analog video link at 2.414 GHz.

The NIST paper lists a number of ways to improve urban search and rescue wireless communications. Options, some of which are currently being investigated by robot manufacturers, include changes in frequency coordination, transmission protocols, power output, access priority, and using relay transformers to increase the range of wireless transmissions (a technique known as multi-hop communications). The paper also suggests establishing new access schemes or software-defined radios that allow interoperable communications.

The August 2006 US&R DHS/NIST robot exercise at the Montgomery County Fire Academy in Gaithersburg offered emergency responders an opportunity to deploy robots in realistic training scenarios as well as helped robot developers and manufacturers refine designs and better understand performance requirements. The work is funded by DHS's Science and Technology Directorate through NIST's Office of Law Enforcement Standards.

* K.A. Remley, G. Koepke, E. Messina, A. Jacoff and G. Hough. Standards development for wireless communications for urban search and rescue robots. 9th Annual International Symposium on Advanced Radio Technologies, Feb. 26-28, 2007, Boulder, Colo.

Technical Paper [PDF]
Conference Presentation [PDF]

Media Contact: John Blair, john.blair@nist.gov, (301) 975-4261

You may wish to go to the original web page to get this:
www.nist.gov/public_affairs/techbeat/tb2007_0301.htm#robots