Radio localization

Precise measurement of distance with Bluetooth

23. Juni 2022, 6:00 Uhr | Harry Schubert
Ken Kolderup, Chief Marketing Officer (CMO) der Bluetooth Special Interest Group (SIG)
Ken Kolderup, Chief Marketing Officer (CMO) of the Bluetooth Special Interest Group (SIG).
© Bluetooth SIG

Many are unaware that Bluetooth technology is now also a leading wireless positioning technology. We spoke to Ken Kolderup, Chief Marketing Officer of the Bluetooth Special Interest Group (SIG), about the technology, its use, and the future of Bluetooth location services.

Bluetooth technology is mostly known as the leading standard for wireless audio streaming, with over 1.4 billion audio products expected to ship in 2022 alone. Much of the world is also aware of its being the leading wireless standard for low-power data transfer, with just over 1 billion Bluetooth connected devices expected to be sold this year, from fitness through wellness products to every kind of consumer electronics.

But, more than 250 million Bluetooth devices will probably also be shipped this year to support location service solutions.

?   What’s the current state of Bluetooth location services?

!   Ken Kolderup: Location services is actually the fastest growing area for Bluetooth technology, with over 550 million products expected to ship in 2026 alone. One reason for the rapid growth is that SIG members have continued to meet market demands by adding more advanced positioning capabilities. Even now, a project to add high-accuracy distance measuring capability is well underway within Bluetooth SIG. And promises to enhance the performance of all manner of locating solutions.

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Ken Kolderup, Chief Marketing Officer (CMO) der Bluetooth Special Interest Group (SIG)
Ken Kolderup, CMO of Bluetooth SIG, heads an international team responsible for marketing, business development, and developer relations. His team cooperates with over 3538,000 member companies to increase the awareness, understanding, and adoption of Bluetooth technology. Kolderup comes with more than 25 years of marketing, business development, and general management experience. Most recently he served as CMO at Taqua, a key innovator and leading supplier of virtualized core network solutions to mobile operators worldwide. Prior to Taqua, Kolderup was CMO of Kineto Wireless, as well as general manager of the company’s core network products business unit. Kolderup holds a BSc in electrical engineering and MSc in industrial engineering from Stanford University.
© Bluetooth SIG

?   What methods does Bluetooth use to determine location?

!   Kolderup: Bluetooth’s role as a positioning technology began with the launch of Bluetooth Low Energy or LE over ten years ago. It introduced the ability of a Bluetooth device to broadcast short advertising messages that any other Bluetooth device nearby could receive. Primarily used to support a subsequent pairing process between two devices, you now find Bluetooth advertising in countless applications where one device needs to determine the presence of another.  For example, regardless of the technology used for Internet connectivity, many IoT solutions use Bluetooth Advertising to support device onboarding.

Bluetooth LE also introduced the ability for one device to estimate the distance to another by a feature known as Received Signal Strength Indication or RSSI. I don’t think anyone ever imagined this basic ability to estimate distance between two devices based on the strength of the received Bluetooth radio signal would now be powering everything from finding a consumer item to sophisticated Real Time Location Systems or RTLS, capable of tracking thousands of assets in a commercial and industrial environment with meter-level positioning accuracy.

While location services solutions based on RSSI have seen tremendous success, it showed some years ago that the market demanded technologies enabling even higher levels of positioning accuracy. In some RTLS deployments for example, the solution must be able to provide location accuracy measured in centimeters rather than meters. So, the Bluetooth community embarked on projects to add more advanced positioning capability.

Bluetooth localization

RTLS Device Shipments
© Bluetooth SIG
Anwendungen der Bluetooth-Ortung.
© Bluetooth SIG
Branchen die Bluetooth-Ortung anwenden wollen.
© Bluetooth SIG

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?   And how are these projects progressing?

!   Kolderup: The first was completed in 2019 with the introduction of Bluetooth Direction Finding, enabling one Bluetooth device to determine the direction of a signal transmitted from another. By adding support for high-accuracy signal direction determination, RTLS asset tracking solutions could now start delivering centimeter positioning accuracy. As an extreme example, many ice-hockey leagues are now deploying RTLS solutions based on Bluetooth Direction Finding that can track player and puck movement with centimeter accuracy, and latency measured in milliseconds.

A second project, now reaching the advanced stages of specification development within the Bluetooth SIG, is that of enabling high-accuracy distance measurement. Similarly, to how the direction-finding project brought the well-proven practice of radio direction finding to Bluetooth technology, the distance measurement project is now working to bring well-established wireless ranging techniques to the Bluetooth standard. Coming soon, this new feature is expected to further enhance the performance of many Bluetooth RTLS solutions.

?   Is there one particular application area that will benefit from this enhancement?

!   Kolderup: One rapidly growing demand for the new feature is access control, like using your smartphone as a digital key to access your car, home, and more. Most digital key solutions today are already based on Bluetooth technology, but the addition of high-accuracy distance measurement promises to further enhance the user experience they provide, as well as introducing an even greater level of security.

?   Thank you for this rundown, Ken.


Lectures on the topic at the Embedded World Conference 2022

Date Time Session Title Speaker
23.6. 16:00–16:30 Session 2.9 Bluetooth Localization Bluetooth Direction Finding: An Overview of AoA and AoD Technologies Fabio Belloni, Quuppa
16:30–17:00 Taking Bluetooth Direction Finding Beyond the Theory Sami Kaislasuo, Silicon Labs
17:00–17:30 Bluetooth 5.1 Based Indoor Localization: Performance Results and Insights Gerrit Maus, University of Wuppertal


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