Patent ID: 8604972

Claim:
A position measuring device by means of GPS, the device measuring a three-dimensional position of a moving object based on GPS ranging data obtained at a reference station that is a reference GPS receiver installed on ground and GPS ranging data obtained at an observation station that is an observation GPS receiver disposed on the moving object to be located, the position measuring device comprising multiple solution calculating sections that receive the GPS ranging data from the reference station and the GPS ranging data from the observation station and calculate RTK solutions, including a fixed solution and a float solution, as position data of the observation station according to a real time kinematic (RTK) technique, the solution calculating sections being sequentially restarted at predetermined time intervals, the position measuring device further comprising a solution obtaining unit for receiving the RTK solutions outputted from said solution calculating sections and obtaining an optimum fixed solution; the solution obtaining unit comprising: a number decision section for deciding whether or not the inputted RTK solutions include multiple fixed solutions; a deviation calculating section for determining, when the number decision section decides that the RTK solutions include multiple fixed solutions, deviations between the fixed solutions; and an allowable value decision section for deciding whether or not the deviations calculated by the deviation calculating section exceed an allowable value, wherein when the allowable value decision section decides that none of the deviations exceed the allowable value, said optimum fixed solution is obtained based on the fixed solutions, when said number decision section decides that the number of fixed solutions is one, the fixed solution is outputted from the solution obtaining unit; and when all of the deviations exceed the allowable value in the allowable value decision section, all of the obtained fixed solutions are cancelled.