In the most challenging rescue situations, it’s vital that first responders know both where they are and where to go. But when visibility is hindered by smoke or darkness, they need a “sixth sense” that guides them in the right direction – and we’ve been working on a wearable technology that could allow the makers of personal protective equipment (PPE) to offer just that.

Lost in the darkness?

Imagine you’re in a room you’ve never been in before, and it’s full of smoke. You can’t see your hand in front of your face, and there’s fire all around. If you need to find your way out, you had better keep calm, have perfect memory, and know exactly which way to go.

However, that’s rarely the case. In fact, becoming disorientated in a smoke-filled building is one of the most commonly reported issues facing firefighters, leading to valuable time being wasted, and an increased risk of lives being lost.

But what if we could provide first-responders with a directional “sixth sense”, so they almost intuitively knew their exact location and the way to safety?

Dialling-down the build-up of error

When you’re trying to find your way through a room without visual cues, a big problem is the build-up of error over time, because it means that your perception of location gradually becomes less and less accurate.

This also applies to the inertial measurement unit (IMU) sensors used in conventional position-locating devices, just as much as it does to finding your way when you’re blindfolded. Data on changes in speed or direction always comes with an error, and with each additional change these errors mount until the accuracy of the readout is no longer fit for purpose.

Three steps to improving accuracy

We’ve been working on three ways to reduce the errors associated with positional measurement, while keeping the costs down by sticking to affordable IMU sensors:

  • Getting more data: Part of the problem of measurement ‘drift’ can be solved by simply using more IMU sensors – essentially tackling the problem with statistics. But how many sensors do you need to make a difference? We’ve done some modelling to work out where the sweet-spot lies.
  • Building in reference points: If the measured position has drifted from the true position over time, then you can get back on course by using reference points, or anchoring. And by using behaviour-based modelling, we’ve come up with a nice way of doing this, even when a building plan isn’t available.
  • Using people-power: First-responders never work alone, and we’ve realised there’s opportunity to capitalise on the multiple independent location measurements that would be made during an operation.

By integrating the information provided by the above three routes, we’ve found you can substantially increase the accuracy of the predicted position measurement.

sketch of a fire belt
Fire belt sketch

A “sixth sense” of direction for first-responders

Measuring someone’s location is only part of the solution. We still need to relay this vital positional awareness to the rescue worker. We’ve done this by means of a wearable belt with pager-style actuators around the waist like a compass to let them know which way to go.

Although there are many different types of feedback, including visual and auditory indicators that could be integrated into existing wearables, we opted to use a haptic solution. Similar belts have been used before to give users a sixth sense of magnetic north.

A user can be consciously guided by the belt, but over time the body interprets the vibrations by remapping its existing nervous system, giving the user a subconscious sense of direction. When first responders have more pressing and urgent considerations on their mind, “just knowing” where to go could be critical to mission success.

To find out more about how we improved measurement accuracy in this project, get in touch.

Simon Shakespeare