Position detection system and position detection method

A position detection method using a position detection system,

• the position detection system including:
• a mobile station having a mobile station reference clock circuit, a radio signal transmission circuit, and a transmission antenna;
• a reference station having a reference station reference clock circuit, a radio signal transmission circuit, and a transmission antenna;
• and
• at least three or more fixed stations each having a fixed station reference clock circuit, a radio signal reception circuit, and a reception antenna,
• the position detection method comprising:
• asynchronously and independently operating each of the fixed station reference clock circuits of the three or more fixed stations to generate reference clocks with same frequency as one another;
• intermittently transmitting at least one first radio signal based on a reference clock of the mobile station reference clock circuit in the mobile station;
• disposing the reference station at a predetermined position and intermittently transmitting at least one second radio signal based on a reference clock of the reference station reference clock circuit;
• in each of the fixed stations, receiving the first radio signal and extracting a phase difference between a carrier included in the first radio signal and each of the reference clocks of each of the fixed stations, receiving the second radio signal and extracting a phase difference between a carrier included in the second radio signal and each of the reference clocks of each of the fixed stations;
• and
• canceling a phase offset of the reference clock of each of the fixed stations using phase difference information between the mobile station and each of the fixed stations and phase difference information between the reference station and each of the fixed stations, obtaining distance information between each of the fixed stations and the mobile station, and calculating a position of the mobile station.