| 摘要 |
<p>PURPOSE:To enable correct position measurement by making calling signal and response signal be of the same frequency and by emitting the response signal from a transponder with a certain delay time after receiving the calling signal, in order to remove influence of reflected wave of the calling signal from the sea bed or the like. CONSTITUTION:A transponder 10 does not emit response signal immediately after detection of calling signal but waits for a certain delay time duration. A submerged position measurement device 30 masks received wave signal data for a time longer than the delay time after the calling signal is emitted. Reflected wave data from sea bed, etc., to be input to a wave transmitter/ receiver 20, is masked and therefore influence by the reflected wave can be removed. The masking is released at the timing when the responding signal is emitted from the transponder 10 with a certain delay time and can be input to the wave transmitter/receiver 20, and also there remains no influence of the reflected wave. By this procedure, correct position measurement can be well conducted.</p> |
