Kate Remley, an electronics engineer at the National Institute of Standards and Technology (NIST), addresses how robotics measure up during search-and-rescue incidents, issues with interference and future trends.
Kate Remley received a Ph.D. in electrical and computer engineering from Oregon State University, Corvallis, in 1999. Shortly afterwards, she joined the electro-magnetics division of the National Institute of Standards and Technology (NIST), Boulder, Colo., office as an electronics engineer. Her research focuses on wireless systems and developing methods for improved radio communications for the public-safety community. She joins Associate Editor Mary Rose Roberts to discuss how robotics measure up during search-and-rescue incidents, issues with interference and future trends. (You can also listen to the full podcast.)
Do robots have the potential for providing search-and-rescue assistance to first responders?
The first-responder community is very interested in using robots in a number of situations where it may be too dangerous for a human to be involved in an incident, for example during a chemical release or a building collapse. Currently, robots are being used by the bomb disposal community. So in cases where we don't want to send a human being in because of some sort of environmental conditions, robots have the possibility of really helping the response community.
Most robots are controlled wirelessly. Are there issues with interference or signal loss?
In fact, that's one of my main areas of research in the electro-magnetics division. Many robots are actually controlled using a tether, some sort of a wire that can be used to send video back from the robot to the operator. But more and more, responders would like to use robots wirelessly. This gives them the freedom to go into some sort of rubble pile, or go longer distances… And there are some issues with wireless communications. There are three main impairments that wireless devices experience. Those can be classified as reduction in signal strength — so if you go inside a building or as you go through a wall or structure it means you lose communications with, let's say, an incident commander outside of a building. That's a serious issue, especially in cases where we want to send a robot into a tunnel, which is below the earth so there is a lot of signal reduction, or, in the case of a building collapse where there is a lot of building material it can reduce the signal level. Another impairment of wireless environments is called multi-path and that involves reflections of signals off of buildings and other structures. Those signals can cause interference with a wireless signal. That can have an impact on wireless communications, mainly in an outdoor-to-outdoor situation. The third main impairment, and this can be a significant issue, is interference when wireless devices being transmitted on the same frequency interfere with a signal being transmitted by a responder — who may be trying to control a robot as it is going into a building.
So, some of the robots being deployed right now use unlicensed frequency bands — which means there is a number of wireless devices operating in the same frequency band. So these unlicensed devices have the potential to interfere with the critical communications the first responders are trying to conduct between the incident commander and the robot, essentially.
Is NIST currently working on any performance standards for robots involved in search and rescue?
NIST has an extensive program being funded by the Department of Homeland Security standards office. There's all this great technology out there; robots hold the potential for saving the lives of first responders. But there are very few performance standards that exist, especially for the response community. So DHS has asked NIST to figure standards not only on the wireless links of robots but also for the other types of performance: How well do they operate on a slanted plane, do they go up stairs well, can they find their way in the dark, can the recognize objects and transmit that back to the operator in typically emergency response environments? So what NIST has done is set up a series of field exercise stations that simulate various emergency response scenarios. For example rubble pile or recognize an object in the dark. The robot is rated on how well it can get through an obstacle course that NIST developed. The idea is that by getting the information, manufacturers can develop next-generation version of robots that are more applicable to response scenarios. It also lets NIST develop standards that will help response organizations purchasing robots that are most appropriate for their particular scenario.
In the area of communications, what performance requirements did first responders expect to see in robotics?
It will depend on the application of the specific response agency. Most responder agencies at least want to be able to control the robot in a line-of-sight condition. Perhaps, send the robot down range up to 1 kilometer. So control the robot and receive video feed from the robot, so we call that stand-off operation. Another common scenario is a non-line-of sight situation where a robot goes down range and then goes behind a building. So if you are in a bomb squad agency, you don't want to be right in the path of the suspected explosive, you want to be around the corner. So you've got to be sure you can control your robot as it goes around a corner.
What has your research found about line of sight vs. non line of sight usage of robots?
I mentioned that many of the robots being developed right now use these unlicensed frequency bands. The issue there is that other commercial applications — or even consumer applications use the same bands, for example, your wireless network at home operates in the unlicensed band. Some of the robot communication systems out there operate on the same frequency bands. So there is an issue with a consumer device entangling an emergency response scenario, essentially shutting the robot down. The other issue there is that robots… you may want to deploy more than one robot and you don't want multiple robots to interfere with each other, either. In the case of the emergency responder, they really need to know their systems are going to operate close to 100%, without slowing down or dropping data. The interference issue can be very serious. And we have found in our initial field tests that this can be a significant issue.
What options exist for mitigating radio interference?
One of the easiest is to not use the unlicensed frequency band. The issue there is that there is a limited amount of spectrum available to emergency responders that's been allocated by the Federal Communications Commission. So, that is a strategy. Robots would like to transmit not only the control of the robot — which is a very small amount of data — but also video, which is quite data extensive. So there is an issue with bandwidth and that the robots need a significant amount of spectrum to transmit the video signal. That's one option. Frequency coordination has been used for years with handheld radios and that is a very reliable and robust way of mitigating interference — except when response agencies come from other jurisdictions. Then, coordination of frequencies can be a little challenging.
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