| 摘要 |
PURPOSE:To enable accurate measurement of drift velocity by using a bipolar navigation apparatus adapted to track signals received automatically correcting the moving velocity of a sample timing to determine a drift velocity from a velocity with respect to water, a course and the correction value obtained. CONSTITUTION:In a bipolar navigation apparatus, as signals move to B from A at a velocity ve with the movement of a ship, a sample timing Tm at the tracking point must be altered to Tm'. From the velocity with respect to water obtained from an electromagnetic log, an estimated movement velocity v of said timing is determined. A unit value is added to or subtracted from the velocity v until the polarity of the signal at two timings Tf and Tb before and after the timing Tm corresponding to the velocity turns to positive and negative to cor- rect the velocity v by a correction value vc. The correction value contains drift velocity information. Therefore, the drift velocity is computed in the latitude and the longitude from the value vc, the velocity with respect to water, line-of-position data of the master station and the slave station. |
