| 摘要 |
<p>PURPOSE:To measure the initial velocity of a shell with high precision without any restriction of the mounting place of an antenna, by compensating the wide angle characteristic of the radiation pattern of the antenna when the initial velocity of the shell at the muzzle of a gun is measured based on a Doppler signal according to the velocity of the shell. CONSTITUTION:An electromagnetic wave generated by a microoscillator 1 is led to a directional coupler 3 via a circulator 2. A power is distributed to an antenna 4 on one hand and to a small-sized electromagnetic horn 5 on the other by the coupler 3 and electromagnetic waves are emitted in the air by these devices. In this way, the emission characteristic at a wide angle is raised to an appropriate level by adding the horn 5 to the antenna 4, while the depth of a zero point is lessened and the number thereof is reduced. The continuous electromagnetic wave emitted in the air is applied to a shell and a reflected wave therefrom is received by the antenna 4. The reception signal is given to a mixer 6 through the intermediary of the circulator 2 and subjected to homodyne detection at this mixer 6 to obtain a Doppler frequency, and the initial velocity of the shell is displayed in a display unit 15 based thereon.</p> |
