THREE-DIMENSIONAL POSITION MEASUREMENT BY COMMUNICATION SATELLITE

PURPOSE:To measure the three-dimensional position of an object which is traced to its position at a measurement precision of 1mm or less by transmitting and receiving electric waves in a given procedure among the object, a wave relay which is mounted on a satellite and a ground fixed station (thereinafter called 'three stations'). CONSTITUTION:Electric waves transmitted and received in a given procedure among three stations are stored in a memory of a computer connected to a ground fixed station. A distance among three stations is measured from a time for carrying waves transmitted and received among three stations. The measurement of the wave carrying time among three stations is carried out many times to take a correlation among elapsed time mechanisms provided in three stations by using a statistical method, based on a elapsed time mechanism provided in the ground fixed station. Because waves are refracted by the effect of atmospheric gas, calculation for correcting the length of waves passing through the atmosphere is carried out. In order to instantly measure a distance among three stations, the elevation and azimuth angles of waves transmitted and received among three stations are determined from the wave carrying time among three stations.