航行用100KHz電波帯の伝播特性の解析とそれらによる船位精度の改善-I : ロランC…I(日本航海学会第38回講演会)

抄録

In summer, SS3 rate of Loran C is simultaneously measured by visual receivers of three types at two points which distance is about 150 miles in East China Sea. Additionally, the other data obtained at various points in spring and autumn are introduced for reference. The outlined features of both the coverage of ground and sky waves (contains the diurnal changes of reflecting height) is defined. The deviations from the computed value of sky wave (fig.5) are constant, as a result, the ionospheric heights of day and night will be adjusted. The deviations of integer multiply of 10 microseconds are commonly seemed to be due to unavoidable characters of such visual receiver. The author, however, supposes that the deviation is caused by the correlation of geographical position, the characteristics of propagation and the solar time. Because the 10 microseconds deviation of upper side of standard value are obtains in Tanegashima (2 position), (fig.2, 3), on the contrary, that of Mejima and Yamakawa are in lower side. When the transmitting station is in the eastside of receiving point the deviation might be in lower side, on the other hand, in the westside is in upper side. The time of sunrise is completely coincides with the variation of the height of ionosphere in daytime, but the height of nighttime is slowly changeable. The average deviation of X chain over land at Mejima is +2.3 microseconds.