摘要
长边GPS观测边长与坐标边长的不一致性与使用基准及基准转换模型有关。其主要原因是 1 954坐标系自身的缺陷 ,即高程异常偏高和平差变形及误差积累。因此 ,进行GPS的WGS - 84坐标向 1 954坐标转换计算时 ,应尽可能选择参考点作对比分析。若满足精度要求 ,可采用全国精密参数作转换计算 ,若不能满足精度要求或不知道实际测点 (相对地面点 )的点位误差 ,可先将边长作高程异常改正 ,再相对起算点作方位改正。一般地 ,地面控制点少于三个 ,边长达数百km时 ,基准转换可采用全国精密转换参数 ,边长作高程异常改正 ,利用已知点作约束平差 ;地面控制点有三个以上时 。
The differnece between observation values of long side-length and the side-length values which is calculated from the coordinates is caused by excessive height anomaly, adjustment transfiguration and error cumulation. Transforting from WGS-84 system to BJCS 1954, known points would be analysed completely. When to need, side-length values are corrected with height anomaly, and the azimuth of sides should be corrected as well. Under the control of known points exceeding three points, restriction adjustment is gone on.
出处
《地矿测绘》
2000年第3期25-26,21,共3页
Surveying and Mapping of Geology and Mineral Resources
关键词
长边GPS控制测量
基准转换
高程异常改正
Long Side-length GPS control surveying
Datum transformation
Correction of height anomaly
Transformation coefficient
Azimuth correction
Restriction adjustment
