Besides providing communication between devices, BLE can also be used for positioning by determine the approximate distance between the devices. Positioning can be helpful in some applications like social distancing devices that need to determine when two things (i.e. people, devices, tags) are in close proximity.

A somewhat similar method that has been around for decades, but just recently started making its way into everyday devices is Ultra-Wide Band (UWB). For example, most of the smart phone makers like Apple and Samsung have started incorporating UWB technology into their devices.

At ARIN Technologies, all of our products like ARINAlert and the new SocialDistancer digital PPE devices rely on UWB and here is why.

Reason #1 – Bandwidth

UWB and BLE are similar in that they are both low-power radio systems. However, the biggest differentiator is the bandwidth.

Typical bandwidth of UWB is 500MHz compared to 20MHz for BLE. This massive bandwidth differential, along with other characteristics, makes UWB more suitable for positioning.

It [BLE] was not made for tracing, but at least it can give an indication [of] which other phones have been in close range.

Sven Mattisson, Bluetooth designer and engineer, Ericsson AB, 1995

Reason #2 – Time-of-Flight

UWB uses a technique called Time-of-Flight (ToF) to calculate distances. It is similar to echo location used by bats. On the other hand, BLE uses Received Signal Strength (RSS) for calculating position.

As an example, consider six people, each with a PPE device that can communicate with each other. Each person is anywhere from one to five meters from the center (0 meters) person as illustrated below.

The ToF method of computing distance is through timestamps and does not require the devices (tags) to be in Line of Sight (LOS) with one another. The normal distribution curve for distance calculated using ToF between different devices at different distances is shown in Figure 1. As you can clearly see, each distance is very distinguishable and within an accuracy of 10 centimeters.

Figure 1

As mentioned above, BLE uses RSS to measure distances between devices. The normal distribution curve for RSS indication is shown in Fig.2 and indicates the unreliable nature of BLE to differentiate devices even when they are 1 meter apart.

Figure 2

Another interesting point about Figure 2 is that the tags are in LOS with each other. While the yellow curve can be clearly distinguished, the others are not.

For this example, the device represented by yellow curve is placed right on top of the receiver while the other six devices are spread 1 meter apart (or anywhere from one to six meters from the receiver). As shown, you cannot distinguish whether a distance is 1 meter or 6 meters because there is no clear relation between RSS and distance outside of an ideal environment. As such, this is the reason why BLE can only provide proximity and not precision.

Reason #3 – Non-Line of Sight

In Non-Line of Sight (non-LOS) situations, the UWB radio signal will be attenuated, but the signal strength measurement is not used for range calculation. As such, the timestamps required by the ToF technique remains accurate in calculating the distance with an accuracy of 10 centimeters. We have tested our UWB devices in non-LOS situations where there are obstacles (e.g. concrete blocks, humans, etc.) and the distance calculations have always been accurate.

To see ARINAlert at work in a non-LOS scenario, please view our video.

In contrast, BLE’s reliance on RSS for distance calculations can be negatively influenced by external environmental factors. The signal can be diminished, reflected, or even amplified, thus resulting in unreliable calculations. For instance, if the person is simply turned away from the receiver, the distance calculated by RSS is greater than the true distance and thus inaccurate.

Need to learn more?

Here are two articles that might be of interest.

FiRa Consortium – How UWB Works

ElectronicDesign. – What’s The Difference Between Measuring Location By UWB, Wi-Fi, and Bluetooth?

Conclusion

UWB with the ToF technique is the more accurate method of measuring distances when compared to BLE with the RSS technique. This is critical for social distancing and contact tracing applications, where accuracy and precision can make or break the effectiveness of a safety system.

The post BLE vs UWB – Which Social Distancing Technology is Right for You? appeared first on ARINAlert - Forklift Pedestrian Collision Avoidance System.

According the latest CDC guidance, the virus is thought to spread mainly from person to person:

• Between people who are in close contact with one another (within about 6 feet, which is about two meters)
• Through respiratory droplets produced when an infected person coughs, sneezes, or talks

While masks can help with the “respiratory droplets”, it does not tell workers, busy doing their job, that other workers are within the 6 feet (2 meter) close contact zone.

This is where our new SocialDistancer can provide busy workers with the alerts they need. Unlike Bluetooth devices, our devices use proprietary Ultra Wideband (UWB) technology that is much more precise when calculating distances, providing a more reliable alert. Bluetooth uses Received Signal Strength Indicator (RSSI) for distance approximation which leads to unreliable alerts and false positives for contact. In other words, while you want workers alerted, you don’t want errant alerts which not only distract workers from their task but provides unreliable contact data.

Speaking of contact data, the SocialDistancer records recent contacts so in the unfortunate event of a worker testing positive for COVID-19, you have a record of recent contacts and can take appropriate actions. And for worker privacy, contacts are anonymous, based on unique ARIN ID’s.

To help manage all of the data, it can be easily be uploaded and retrieved from our cloud servers.

Lastly, the SocialDistancer is designed for industrial ruggedness and split-second response times so you and your workers can get on with your work knowing that SocialDistancer is standing watch.

To recap, here is why you should choose SocialDistancer:

• Alerts are given at precisely 6 ft (1.83 m)
• Contacts are cached at 6 ft, no false positives
• Contacts are anonymous, based on unique ARIN ID’s

If your business is ramping back up, SocialDistancer can help. For more information, visit www.socialdistancer.us

SocialDistancer is a trademark of ARIN Technologies

The post Introducing SocialDistancer appeared first on ARINAlert - Forklift Pedestrian Collision Avoidance System.

Can we do it? Yes, we can!

At the core of ARINAlert is the ability to measure distances accurately and making decisions rapidly based on those measurements. It is a natural extension to give social distancing alerts.

How did we respond to such requests? Initially, we considered a single request to be an outlier and added it to the backlog. Several in-bounds later, we ran a short experiment. In this case, we packaged 2 pedestrian wearables with lightly customized software, added a buzzer and, voila, we created one social distance alerting system.

The ARINAlert wearable now provides a protective bubble.

Workers within 6 feet of each other (aerosol droplet range) receive a warning beep of 2 Hz and workers within 3 feet of each other (large droplet range) hear a danger beep of 4 Hz.

Stay away. Stay safe.

Now that we have established feasibility, we ask ourselves,

“Should we do it?”

It is understood that people need to feel safe at work. No employer wants the liability of exposing workers to illness, and nobody wants to get sick, especially when the consequences are high, but we have some questions:

• Are people serious about investing in social distancing PPE?
• Is social distancing a fad? Will people still care about this scenario after the curve has flattened and things return to normal?
• In the wake of reduced productivity and trillions of dollars of economic damage, will widespread adoption of outbreak prevention technology become a priority?
• Is it worth spending time to complete the development and commercialize social distance alerting?

What do you think? Will social distancing alerts become a thing?

Send us a note at info@arintechnologies.xyz and let us know what you think.

The post Will social distancing alerts become a thing? appeared first on ARINAlert - Forklift Pedestrian Collision Avoidance System.