An in-vehicle system includes: a position information reception unit configured to receive position information from a satellite positioning system; a first control unit; a communication line connected to the first control unit; and a second control unit that is connected to the first control unit through the communication line and has a first conversion process unit configured to convert a datum of the position information. The first control unit is configured to transmit the position information received by the position information reception unit to the second control unit through the communication line, and the second control unit is configured to convert a datum of the position information received from the first control unit by the first conversion process unit.