Patent ID: 7671790

Claim:
A communication base station which is communicable with a positioning device being located at a position by using satellite signals from a plurality of positioning satellites, is located at a fixed position, and includes a storage section which stores a program, the communication base station being a section which operates by executing the program and functioning as: a propagation time calculation section which calculates a propagation time required for a communication radio wave to propagate between the communication base station and the positioning device; a propagation time evaluation section which determines whether or not the propagation time is within a predetermined allowable time range; a satellite signal reception section which receives the satellite signals; a code phase calculation section which calculates a code phase of each of the satellite signals; a positioning-side code phase reception section which receives a positioning-side code phase which is a code phase of each of the satellite signals calculated by the positioning device; a difference calculation section which calculates a difference between the code phase calculated by the code phase calculation section and the positioning-side code phase received from the positioning device; a difference evaluation section which determines whether or not the difference is within a multipath range which is a difference range when the positioning-side code phase is affected by a multipath; and a correction value transmission section which transmits the code phase calculated by the communication base station to the positioning device when the difference evaluation section has determined that the difference is within the multipath range.