Factory systems almost always use the vehicle sensors in addition to GNSS, some early systems only had this ability since GPS wasn’t used. Most cars have speed

Factory systems almost always use the vehicle sensors in addition to GNSS, some early systems only had this ability since GPS wasn’t used. Most cars have speed sensors, compass and steering angle sensors, but having that work with a smartphone is another problem. Also there were these things: https://www.thedrive.com/news/34489/car-navigation-systems-before-gps-were-wonders-of-analog-technology https://www.thedrive.com/news/34489/car-navigation-systems-b...