Many technologies onboard vehicles provide local or relative localization. GNSS provides an absolute localization solution, and with the following technologies can achieve the accuracy and availability requirements of a full autonomous driving solution.
In order to receive the best possible accuracy it is recommended that two or three frequencies broadcasted by each GNSS constellation (GPS, GLONASS, Beidou and Galileo) be used.
GNSS signals, without corrections, provide positioning accuracy of five to ten metres (16-32 feet). Corrections can be generated by a number of sources or methods, and system developers must choose the corrections method that best meets the demands of their application. NovAtel CORRECT, the algorithm embedded on all NovAtel GNSS receivers, optimizes all correction methods.
Corrections work in combinations with multi-frequency measurements from the GNSS to provide sub-decimetre to centimetre-level accuracy – depending on the correction source.
RTK sends data from reference receivers in the vicinity of the vehicle. Location can be covered by one or more RTK networks, available free of charge or for a subscription fee.
PPP uses globally available corrections using a world-wide network of reference receivers. Corrections are transmitted to the vehicle via satellite or by cellular. NovAtel utilizes TerraStar corrections to deliver a sub-deceimetre solution.
Components like radar, LiDAR and cameras are used to provide the distance to objects that surround the vehicle. If the exact location of the surrounding objects is known, this technology can provide the absolute vehicle location with assistance from a high amount of map data. When integrated with complimentary technology such as: ultrasonic, interial motion, digital maps, radar/LiDAR and cameras, GNSS acts as the sixth sense to deliver the positioning performance required by autonomous vehicles.