Interoperable indoor positioning systems can determine locations of people and objects within buildings

Maxim Van de Wynckel, a researcher at the WISE lab of the Vrije Universiteit Brussel (VUB), successfully defended his Ph.D. in computer science on 30 June 2025. Over six years, he explored a major challenge facing many modern technologies: How can indoor positioning systems—which determine the location of people or objects inside buildings—work better together?

Indoor positioning, also known as indoor localization, is used in a wide range of applications. Think of apps that guide you through a hospital, systems that track the movement of goods or equipment in a factory, or technologies used in museums, airports or shopping centers. But there is a significant problem: Most systems are built for one specific building or scenario. They “speak” different technical languages and are not compatible with one another.

“There are many different technologies in use—like Bluetooth, Wi-Fi, or sensors—but they aren’t linked or interoperable,” explains Van de Wynckel. “That makes it hard to reuse systems or to securely share data between them.”

In his Ph.D. thesis, he has developed several solutions to tackle this issue. One of them is POSO, a kind of dictionary that allows different systems to describe locations in a similar way, enabling them to better understand each other’s data.

He also designed SemBeacon, a Bluetooth-based system that adds semantic information to beacons—for example, letting a device recognize that it is detecting an “emergency exit” or a “wheelchair-accessible entrance.”

Another key contribution is OpenHPS, an open and flexible software platform that enables developers to create new applications using a mix of technologies.

“With OpenHPS, we show that collaboration between systems isn’t some distant ideal. It’s already possible today,” says Van de Wynckel.

A major part of his work also focused on discoverability: How can devices or users quickly know which positioning systems are available in a given environment? He explored various methods, including publishing these services on the web or via Solid pods—personal data vaults where users control who has access to their location data.

“People should remain in control of their own data. That’s especially important in sensitive contexts, such as health care or residential settings,” he emphasizes.

His research has been presented at international scientific conferences. In 2022, he published a paper on the POSO ontology at the International Semantic Web Conference (ISWC), and at the International Conference on Indoor Positioning and Indoor Navigation (IPIN), he presented a privacy-friendly architecture based on Solid.

In 2023, he released the SemBeacon specification, which has since gained traction among developers. Between 2020 and 2025, he also made multiple contributions to the OpenHPS framework, including algorithms and datasets that are freely available as open source.

“My goal is to make indoor positioning technology as universal as GPS, but with a focus on interoperability, adaptability, and privacy,” concludes Van de Wynckel.