PURPOSE: To make a flight possible in a region where the flight is not detected by a radar by a method wherein the difference between the direction of the radar and that of a jammer is obtained and a computing element charged with these data outputs a drive signal denoting the direction and making the difference zero so as to bring the path of flight of the flying object on the straight line connecting the jammer and the radar.

CONSTITUTION: A receiver 4 on a flying object 1 receives through antennas 5 at its rear radio waves from a jammer 7 to detect the direction of the jammer 7 with respect to the axis of the flying object 1 and simultaneously a passive seeker 2 provided at the head of the flying object 1 detects the direction of a radar 6 with respect to the axis of the flying object 1; from the results the difference between the direction of the radar 6 and that of the jammer 7 is obtained. By inputting these data to a computing element 3, a drive signal denoting the direction and making the difference zero is outputted so as to bring the path of flight of the flying object 1 on the straight line connecting the jammer 7 and the radar 6. This method makes a flight possible in a region where the flight is not detected by the radar 6.