Sea Fall Point Measurement Method Based on Cone Angle Intersection

The naval gun strikes against the sea need to measure the deviation of the fall point to determine the accuracy and hit probability. In order to improve the accuracy of measuring the fall point position of the naval gun, this paper proposes a maritime fall point measurement method based on cone angle intersection, which does not need to use the axis angle data of the equipment and eliminates the dependence on the equipment’s axis angle data when measuring accuracy. Firstly, the photographic measurement method is used to achieve automatic optical intersection of single equipment at different moments, using two observation stations and one cooperative target ship. Then, the image data within 10 km from the measured target are collected using two observation stations. The line of sight directions and angles of the two observation stations are combined to measure the target object and the cooperative target ship at each observation station. The constraint of the approximate equal radius of the Earth ellipsoid is added under close range conditions. The cone angle intersection model mapping relationship is established. Finally, the coordinate position of the target object in three-dimensional space is calculated using field tests at sea and compared with the actual position for analysis. The experimental results show that the measured fall point is within 5 m in the range of 700 m with a ratio of more than 75%. This has increased the range of measurement accuracy processing and proved the feasibility of the measurement method. The method can be used for calibrating large and medium caliber naval gun firing to the sea to improve the firing accuracy of the weapon. It has guiding significance for measuring the fall point position of naval guns at sea.