With two types of observations, using Helmert variance component estimation, it can improve adjustment precision through multiple iterations.
并对两类观测值，利用赫尔默特方差分量估计，通过多次迭代计算，提高平差精度。
With two types of observations, using Helmert variance component estimation, it can improve adjustment precision through multiple iterations.
并对两类观测值，利用赫尔默特方差分量估计，通过多次迭代计算，提高平差精度。
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