PURPOSE: To keep automatically height of a navigated object having a means which can raise up and lower down the height (an elevating means) by a method wherein an atmospheric pressure sensor to detect a relative height is provided so that the elevating means is controlled based on its output.

CONSTITUTION: In a fly control of radio controlled plane, various kinds of steering signals are transmitted into air by a wireless steering transmitter 201 in the form of electric wave, received by a wireless steering receiver 202 carried on a navigated object, and at the same time they are received, separated into their original forms. In this instance, as to a height control, the waveform signals are separated into an engine control signal 7 and an elevator signal 8 to drive an elevating steer. Further, an atmospheric pressure signal detected by an atmospheric pressure sensor 6 and a height command signal 4 are compared by a differential amplifier 5 to get a signal which represents a difference. The engine control signal 7 and the elevator signal 8 are mixed with the difference representing signal by mixing circuits 9 and 10, and then, the mixed signals are sent to servo-motors 11 and 12 to control drive of an engine throttle 13 and an elevator mechanism 14.