In order to solve the problem of GPS reliability in the city, Dutch researchers created SuperGPS. Based on the mobile telecommunications network, it allows geolocation to within 10 centimeters, improving, among other things, the reliability of the navigation system of autonomous cars in urban areas.
Current geolocation systems, including GPS or Galileo, can determine their position to the nearest centimeter under ideal conditions. They use triangulation based on the signal emitted by orbiting satellites. However, in urban areas buildings can block or reflect the signal and reduce accuracy to several meters. Geolocation is then no longer reliable enough for certain uses.
Of the dutch researchers have developed a new system, called SuperGPS, which allows geolocation in town with an accuracy of around ten centimeters. Their article, published in the journal Naturedetails how to reuse the mobile telecommunications network as a GPS system.
The mobile system connected to an atomic clock
SuperGPS would use the mobile antennas already in place. The GPS satellites each contain an atomic clock in order to stay synchronized. With the SuperGPS, a single atomic clock would be enough to synchronize the signals from the antennas, thanks to the fiber optic links. To solve the problem of signal reflected or blocked by buildings, their system uses a very wide bandwidth. By reusing the mobile network, the researchers were able to cut out the signal on limited frequency bands very close to those used by smartphones.
The SuperGPS thus offers a positioning of the order of a decimetre, and a synchronization of less than a nanosecond. In addition to increased accuracy for mobiles, this network would be important for quantum communications, as well as improving the navigation reliability of self-driving cars in the city.
