河口海岸的水文、地貌及地质状况变化较大,故在测量中对定位的正确性要求较高。过去通常使用的定位观测工具是罗盘或六分仪,用前方或后方交会确定测量船的工作位置。但是,使用这种方法有许多局限性,如测量范围小,受海况、天气条件的影响较大等。 随着海洋科学的发展,这种传统的定位方法已远远不能满足要求。无线电定位已成为河口海岸研究中的重要手段之一。 Estuary coast hydrology, geomorphology and geological conditions vary greatly, so in the measurement of the correctness of the positioning of the higher. In the past, the commonly used positioning observation tool was a compass or sextant. The front or rear intersection was used to determine the working position of the survey ship. However, the use of this method has many limitations, such as small measuring range, the sea conditions, the greater impact of weather conditions. With the development of marine science, this traditional method of localization has far failed to meet the requirements. Radio positioning has become one of the important means in the research of estuarine and coastal areas.