| 摘要 |
<p>PURPOSE:To obtain a coordinate transformation method in which a coordinate-transformation start address indicating the center of a polar coordinate system is generated while it is being updated a plurality of times during one rotation of an antenna, in which the address is written in accordance with the polar coordinate system using the address as the central point and in a true-motion and north-up mode and in which coordinates can be moved smoothly on a display device. CONSTITUTION:A direction arithmetic part 3 adds an antenna direction given by a direction pulse to a track given by a gyro compass, and it finds a polar coordinate direction so as to be sent to a coordinate transformation part 4. A control part 5 operates a coordinate- transformation start address so as to be given to the transformation part 4. The transformation part 4 generates a write address from the address. In this case, a received signal on a buffer memory part 2 is written into an image memory as radar image data in a true-motion and north-up mode. In addition, whenever the counted value of the direction pulse of an antenna, i.e., the antenna direction, is changed by a prescribed angle, the coordinate- transformation start address is updated a plurality of times during one rotation of the antenna according to the track and a speed. Thereby, a sudden image jump and a rotation on a screen are hard to be generated.</p> |
