| 摘要 |
PURPOSE:To easily and accurately calculate the position and azimuth angle of a shipway from the measured distance values of three unknown sides and the lengths of two known sides, by forming triangles having one side in common on the basis of two known points on a fixed side and two constant points on a mobile shipway. CONSTITUTION:The first quadrant of orthogonal coordinates wherein north and east are made positive is used. The base points A, B on the land are separately obtained and the length of a reference line AB is L1<2>=DELTAX<2>+DELTAY<2> and the azimuth thereof is tantheta1=DELTAY/DELTAX. When a side AC=L2 and a side BC=L3 are measured, the intersectional angles thetaA, thetaB, thetaC of a triangle DELTAABC are calculated from formula I. When the coordinates of the point A are AX, AY, the coordinates of a point C are CX=AX+DELTAx, CY=AY+DELTAy and can be expressed by the length L2 of the side AC and the angles theta1, thetaA according to formula II. Next, in the same way, BD=L4 is measured and a point D is calculated from the information of DELTABCD. When the coordinates of C, D are calculated, the position of a shipway S is calculated and the azimuth angle is calculated from thetaS=tan<-1>(CY-CX)/(CX-CY).
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