| 摘要 |
<p>A PPI sonar which probes underwater sectorial area at the center of which the ship mounted with the sonar is located by rotating a transmitter/recorder, which transmits and receives ultrasonic signals in one direction, within a predetermined range in one and reverse directions in a horizontal plane, and displays the underwater situation on a corresponding wide sectorial displaying region on the screen of the display, with the position of the displayed ship being off the center of the screen. The PPI sonar is provided with means (3, 65) for setting the reference point (B) of rotation around which a transmitter/receiver (4) is rotated clockwise and counterclockwise in a horizontal plane within a probing range of a predetermined direction, or a means (103) for setting the position of the displayed ship; and is so designed as to set a region for displaying the probed underwater state on the screen of a display (14), according to the signal outputted from either one of the means (3, 65) and the means (103).</p> |
