Researchers from Delft University of Technology, Vrije Universiteit Amsterdam and VSL have developed an alternative positioning system that is more reliable and accurate than GPS, especially in urban environments. A working prototype demonstrating this new mobile network infrastructure achieved an accuracy of 10 centimeters. This new technology is important for a variety of location-based applications, including automated vehicles, quantum communication, and next-generation mobile communication systems.

Much of our vital infrastructure depends on global navigation satellite systems such as the US’s GPS and the EU’s Galileo. However, these satellite-based systems have limitations and vulnerabilities. Radio signals are weak when received on Earth, and accurate location determination is no longer possible if radio signals are reflected or blocked by buildings.

“This can make GPS unreliable in urban environments, for example,” says Christian Tiberius, Delft University of Technology and project coordinator, “which would be a problem if we wanted to use automated tools.” Also, our citizens and our government actually depend on GPS for many applications based on location and navigation devices. Also, we didn’t have a backup system yet.”

The aim of the project, called SuperGPS, was to develop an alternative positioning system that uses a mobile telecommunications network instead of satellites and could be more reliable and accurate than GPS.

“We realized that with several advanced innovations, the telecommunications network can be transformed into a very accurate alternative positioning system that does not depend on GPS,” says Jeroen Koelemey from Vrije Universiteit Amsterdam. “We have succeeded and successfully developed a system that can provide connectivity like mobile networks and Wi-Fi networks, precise positioning and timing like GPS.” We’re investigating a navigation system with an accuracy of ten centimeters. Image credit: TU Delft/Frank Auperlé

atomic clock

One of these innovations is to connect the cellular network to a highly accurate atomic clock so that it can broadcast perfectly synchronized positioning messages, just as GPS satellites do with the atomic clocks they carry on board.

These connections are made over the existing fiber optic network. “We have already explored methods of distributing the national time generated by our atomic clocks to users elsewhere over the telecommunications network,” says Erik Dieriks of VSL.

“With these techniques, we can transform the network into a nationwide distributed atomic clock, with many new applications such as very precise positioning over mobile networks. With the hybrid optical-wireless system we have just shown, in principle anyone can access the national time produced in VSL wirelessly. creates an extremely accurate radio clock.”

In addition, the system uses radio signals with much higher bandwidth than normally used. “Buildings reflect radio signals, which can confuse navigation devices. The high bandwidth of our system helps resolve these confusing signal reflections and provides higher positioning accuracy,” explains Gérard Janssen of Delft University of Technology.

“At the same time, bandwidth in the radio frequency range is limited and therefore expensive. We get around this by using a series of combined low-bandwidth radio signals spread over a large virtual bandwidth. The advantage is that only a small part of the virtual bandwidth is actually used and the signals are transmitted to the mobile phone. is that it can be very similar to the signals.’