A positioning system includes the ability to receive GPS signals and to receive and transmit packet radio signals. The positioning system receives GPS transmissions to determine its pseudo position. The positioning system also receives differential corrections relative to its pseudo position using packet...http://www.google.de/patents/US20010041535?utm_source=gb-gplus-sharePatent US20010041535 - Positioning system using packet radio to determine position and to obtain information relative to a position
