A position measurement system for a geostationary artificial satellite, the system comprising: two or more antennas including at least a first antenna and a second antenna that receive, at mutually dissimilar locations, any signal transmitted by a geostationary artificial satellite; storage means for storing a reception signal received by each of the antennas, together with a reception time of the reception signal; correlation processing means for calculating a difference in reception time of a same signal between said first antenna and said second antenna, by performing correlation processing on the reception signal of said first antenna and the reception signal of said second antenna which have been stored in said storage means; measurement means for measuring a first distance between said first antenna and said geostationary artificial satellite on the basis of the measurement result of the round-trip time of a signal between said first antenna or an antenna for measurement disposed close to said first antenna and said geostationary artificial satellite; and calculation means for calculating a distance between said second antenna and said geostationary artificial satellite by adding a second distance (R21b) to the first distance between said first antenna and said geostationary artificial satellite as obtained by said measurement means, the second distance (R21b) being calculated from the difference in reception time between said first antenna and said second antenna as obtained by said correlation processing means, wherein said calculation means performs a first interpolation processing and/or a second interpolation processing in order to obtain a value of the first distance and a value of the second distance (R21b) at the same times, the first interpolation processing being processing for interpolating a plurality of values of the first distance obtained by a plurality of measurements by said measurement means, the second interpolation processing being processing for interpolating a plurality of values of the second distance (R21b) obtained by the correlation processing a plurality of times by said correlation processing means. two or more antennas including at least a first antenna and a second antenna that receive, at mutually dissimilar locations, any signal transmitted by a geostationary artificial satellite; storage means for storing a reception signal received by each of the antennas, together with a reception time of the reception signal; correlation processing means for calculating a difference in reception time of a same signal between said first antenna and said second antenna, by performing correlation processing on the reception signal of said first antenna and the reception signal of said second antenna which have been stored in said storage means; measurement means for measuring a first distance between said first antenna and said geostationary artificial satellite on the basis of the measurement result of the round-trip time of a signal between said first antenna or an antenna for measurement disposed close to said first antenna and said geostationary artificial satellite; and calculation means for calculating a distance between said second antenna and said geostationary artificial satellite by adding a second distance (R21b) to the first distance between said first antenna and said geostationary artificial satellite as obtained by said measurement means, the second distance (R21b) being calculated from the difference in reception time between said first antenna and said second antenna as obtained by said correlation processing means, wherein said calculation means performs a first interpolation processing and/or a second interpolation processing in order to obtain a value of the first distance and a value of the second distance (R21b) at the same times, the first interpolation processing being processing for interpolating a plurality of values of the first distance obtained by a plurality of measurements by said measurement means, the second interpolation processing being processing for interpolating a plurality of values of the second distance (R21b) obtained by the correlation processing a plurality of times by said correlation processing means.