In-Orbit Antenna Pattern Measurements on Engineering Test Satellite VIII

The antenna pattern of a satellite must be measured in the early stages after a launch to confirm that the mechanical environment of the launch caused no damage and to verify the adequacy of the antenna design in the orbit. We describe the in-orbit measurement of the antenna pattern of the large S-band antenna installed on the Japanese Engineering Test Satellite VIII, which was launched in December 2006. An antenna pattern measurement method that estimates with sufficient accuracy under constraint conditions is proposed. The results measured according to the proposed method for the ETS-VIII antenna pattern in the orbit are presented. The results obtained with the proposed method are discussed in relation to the design.