摘要
本文着重论述用新的30°棱镜等高仪同时测定大地方位角A和垂线偏差分量ξ、η的基本理论及作业方法。这种方法有三个特点：1）就方位角而言，观测30°等高圈上的星较观测北极星的地理位置更广阔，前者适用于地球的任意一点，而后者只适用于北半球的中纬度地区；2）利用有限的观测值，即测星的时刻及星和地标的水平方向值，同时解算大地方位角和垂线偏差分量三个未知数，避免了在已知大地经纬度的点上分别测定天文经纬度和天文方位角，而后推算A、ξ和η的传统方法；3）用30°棱镜的上、下棱面观测星和地标，消除了垂直轴倾斜和水平轴轴颈误差垂直分量对星的水平方向值的影响，不需按传统方法加改正数，提高了观测精度。
:
This paper puts stress on the basic theory and operational process for simultaneously
determining the geodetic azimuth A and the components of deflections of the vertical
by newly designed 30° prismatic astrolabe. This method has three features:
(1) As long as azimuth is concerned, observations of stars on 30° almucantar can be
made almost in any place the world over, whereas only the mid-latitude zone of the
north hemisphere is suitable for the observation of polaris: (2) Only the time of star's
almucantar crossing and the horizontal angle between the star and the reference object
are observed; from these limited observations, a simultaneous solution for A and can
be made, thus obviating the traditional process of determining astronomical latitude, lon-
gitude and azimuth at stations with known geodetic latitude and longitude in order to
derive A. ; (3) Observations of star and reference object are made by upper and lo-
wer prism faces respectively; this practice eliminates the influences of the inclination of
vertical axis and the error of trunnion axis on horizontal direction observations without
making it necessary to apply corrections as traditional process does, thereby leading to an
increase in accuracy.
出处
《测绘学报》
EI
CSCD
北大核心
1989年第1期39-50,共12页
Acta Geodaetica et Cartographica Sinica
