PURPOSE: To take an accurate measurement by correcting an error with temperature by calculating a correcting value for the position of a moving body with the temperature in the device from the error characteristics of the position of the moving body with the temperature in the device which are found previously from measured values.

CONSTITUTION: This system consists roughly of a ground device 1 and a moving device 2. This device 1 sends an encoded radio wave m1 from a main station 3, and 1st and 2nd slave stations 4 and 5 receive the radio wave m1 and send encoded radio waves m2 and m3 in synchronism with the received wave. The mobile station 7 of the device 2, on the other hand, receives the radio waves m1 and m2 to find their propagation time difference Δt1 and receives the radio waves m1 and m3 to find their propagation time difference Δt2. Further, an in-device temperature correcting means 10 calculates the correcting value for each station by measuring the temperature in the device by a thermometer. Then, a processing means 8 calculates the position of the mobile station 7 from the time differences Δt1 Δt2 by hyperbola navigation and corrects the position with the correcting value from the means 10, thereby displaying the corrected position on a display means 9.