PURPOSE: To make it possible to guide a guided flying body to a target by a semiactive homing system by installing a radar equipment on ground behind a mountain when there is a mountain which obstructs the radio waves of a radar on the ground and installing a command receiver on a guided flying body and switching a frequency which can be received by the guided flying body by the instructions from the radar on the ground.

CONSTITUTION: A main radar 1 can not detect a target 3 because it is behind a mountain 4, but an auxiliary radar 2 can detect it, and the information on the target obtained by the auxiliary radar 2 is sent to the main radar 1. The main radar 1 carries out the calculation of shooting and shoots a guided flying body 5. Until the guided flying body 5 goes over the mountain, it is guided by the command signal 7 that is given from the main radar 1. When the guided flying body 5 is over the mountain 4, the body 5 receives a standard signal 8 from the auxiliary radar 2 and at the same time the radio waves are shot from the auxiliary radar 2 to the target 3, and the reflection signal 9 reflected from the target is received. The guided flying body 5 receives both standard signal 8 and reflection signal 9 from the target and starts semiactive homing and it is continued until it hits the target 3.