In order to secure accuracy and effectiveness of the electromagnetic compass as information sensor for ship's head up bearing with gyro compass, magnetic compass and electromagnetic compass on the sea and on the dock in land.The results obtained were as follows;1. Between the Northeast and the southsouthwest the deviation on ship's head up bearing on electromagnetic compass got easterly deviation with max. 53℃on the East and between the Southwest and the Northnortheast westerly deviation with max. 34℃ on the Northwest, of which values were not able to be corrected due to the angle excess of deviation adjustment.2. The varies of deviation seemed to have a tendency to increase easterly deviation on the Northeast and the East, easterly deviation after westerly deviation between the South and the Northwest, small one on the North and the Southeast.3. The varies of deviation of ship were larger than the one of around the dock, were extreme on the bow of forecastle deck and were stable on the ship's center line of compass deck at the dock in land.

본 연구에서는 고정된 나침 방위에서 측정한 단일 자차만을 이용하여 자차계수 B와 C를 추정할 수 있는 새로운 방법을 기술하였다. 먼저, 4척의 미해군 함정에서 실제 측정한 자차를 이용하여 자차계수 B와 C만을 적용하여 자차합성하는 경우의 문제점을 분석하였다. 그리고, 최적 추정계수 B와 C의 획득 이론과 절차를 전개하고, 제안한 방법의 유효성을 평가하였다. 평가결과, 추정한 B와 C의 측정한 단일 자차를 최적으로 근사할 수 있음을 나타냈다.