COMMUNICATION DEVICE, COMMUNICATION SYSTEM AND POSITIONING METHOD

PROBLEM TO BE SOLVED: To provide a communication device, a communication system and a positioning method that can eliminate uncertainty equivalent to a maximum one code bit with respect to a distance detected by a GPS using a satellite.SOLUTION: According the present invention, a communication device 1a employing a MSK scheme as a modulation scheme for adding a signal to a radio wave comprises: a multiplier for an orthogonal demodulation of a reception signal; /2 phase shifter; a local oscillation oscillator; a low pass filter (LPF); a base band signal I that undergoes the orthogonal demodulation; a phase calculation part that calculates a tan(Q/I) from a base band Q signal; and a positioning calculation part that performs a positioning calculation from a phase calculation result. According to this configuration, from phase information varying from moment to moment, a distance where the radio wave reaches from each satellite is detected, so that there is no uncertainty (positioning error) that is equivalent to the maximum one code bit like a GPS positioning. Thus, a positioning scheme can be provided that does not exhibit the positioning error in principle.