測定船位に関する95%確率円について(日本航海学会第34回講演会)

抄録

Concerning the probable circle, which is a method of expressing the error boundaries of a ship's position, the writer has investigated the terms in which the probability is 95%, when the accuracies of two position lines are alike ; and moreover he has described the method for applying it to the error boundaries of a ship's position fixed by three position lines, in an earlier paper. [1] However as the coefficient of the probable circle system is determined by the function of the intersecting angle of position lines and the ratio of accuracies of positon lines, he submits the 95% probable circle of the unequal accuracies of position lines, in this paper. The method: As shown in Fig.1, the probability of ship's position within the circle with an arbitrary radius is calculated according to the sum total of probability within the very thin parallelogram. And then the radius of the circle which includes the ship's position with 95% probability is found by repeating the above-mentioned method. However as massive calculation is required to do it, the writer calculated the radius of the 95% probable circle by integrating the probabilities when the ratios of standard deviation (σ_1, σ_2) of two position lines are 1, 2, 3, 5, 7.5, 10, and the other case they were estimated from Fig.3 & 4. The result : The radius of 95% probable circle are shown in Fig.5 & 4 and the coefficient(K) of the circle are shown in Fig.2 & 3.