Achieving high precision GNSS
GNSS correction data enables much higher levels of precision, by cancelling out GNSS errors. This correction data can be gathered using a base station in a known location, which monitors signals coming from the satellites and identifies any discrepancies between its actual position and the one obtained from the GNSS signals. These deviations are then sent to moving ‘rover’ vehicles that subscribe to the service, enabling them to pinpoint their position more accurately by using the correction data to adjust the reading from the GNSS satellites. If conditions are good, and the rover and base station are relatively close together, this technique can deliver centimeter-level accuracy.
However, while correction data can address satellite clock, satellite position and atmospheric errors, multipath errors are often unique to a device’s surroundings, meaning they may differ between the rover and the base station. As a result, these errors need to be tackled within the individual receiver device.
High precision GNSS has been around for some time, but because both the kit and correction services have been so expensive, it’s remained the preserve of a handful of specialist professions, such as surveying. But new technologies are now making high precision positioning accessible to the mass market. This is unlocking use cases such as lane-accurate navigation, precision aerial drone flights and landings, unmanned farm machinery, augmented reality and vehicle-to-everything (V2X) communication, where vehicles wirelessly communicate with one another and the road infrastructure to avoid collisions.