In the context of satellite-based positioning, sensors are used which record and process the signals of the GPS, GLONASS or Beidou satellite navigation systems. On the other hand, the differential approach, in which correction signals are determined with the aid of a reference station, is used to increase position accuracy.
Multi-sensor systems consisting of a camera, laser scanner and GNSS module are used for visual positioning. The GNSS module provides a rough starting position, whereas the reference points detected by the laser scanner and the camera, or the reference points detected therein, allow an accurate determination of the vehicle position.
In areas where no satellite signal is available (e.g. in multi-storey car parks), FusionSystems first uses a network of stationary radio modules to determine the approximate vehicle position. The initialization of the module network is done by solving a non-linear optimization problem regarding the paired distances of the permanently installed modules, which are determined from the signal strengths and running times measured at the beginning. The vehicle position is calculated using the radio signals received from the vehicle from reachable module triplets of the stationary network. In combination with laser-based positioning and the use of a suitable Kalman filter, the system also determines the exact position of areas with low signal coverage.
Direct map matching offers, among other things, the possibility of using highly accurate map data to transform map or object data with insufficient position accuracy. Especially in vehicle navigation systems as well as in simulation environments, the true position on the map plays an important role.