Land vehicle navigation system

摘要

A land vehicle navigation system is adapted to display the present position of a vehicle by receiving signals from a combination of satellites under the global positioning navigation system. The present position of the vehicle is displayed on a screen, superposed over map data. To obtain the best global positioning data, the combination of satellites is selected in connectio with the visibility. To perform the positive reception of signals from the satellites as the vehicle is running in an urban area, data relating to the building height around the area can be obtained from a geographical information section including data indicative of the map and the building height distribution with respect to the area to determine the visibility.