Autonomous vehicles such as cars, trams, boats and trucks are cruising towards becoming a mainstream reality. To achieve full autonomy, onboard systems contain an array of complementing technologies. LIDAR, radar, ultrasonic, inertial sensors, cameras and digital maps are such technologies. However, they can only provide relative localisations. GNSS is the only technology which can provide an absolute position, and hence plays a critical role in any autonomous system. Conventional GNSS receivers typically provide a positioning accuracy of approximately 5 meters (16 feet). With additional correction methods (using RTK, PPP) this can be improved significantly to centimeter level precision.
For accurate positioning, at least two frequencies broadcast by each GNSS constellation (BeiDou, Galileo, GLONASS, GPS, QZSS) should be used for the following reasons:
More GNSS signals are obtained from multiple constellations. Autonomous systems not only require increased accuracy but also reliability, integrity and availability.
Multiple GNSS signals from multiple systems are also indispensable when driving in more challenging environments such as cities, where buildings may block many GNSS satellites.
Atmospheric conditions such as ionospheric scintillation may impact position accuracy and availability. Using multiple frequencies and constellations can help mitigate such errors.
Septentrio’s GNSS technology and positioning engine provides reliable, centimeter-level accuracy and extended availability. The AIM+ anti-jamming, anti-spoofing technology provides reliability and integrity that is indispensable for a self-moving vehicle.