estimation frame的用法和样例：
例句
- Linear measurement equation and linear static state estimation algorithm based right-angle coordinate are proposed when only PMU measurements are used.
在完全使用相量量测的情况下，提出了基于直角坐标系的实数形式的电力系统线性量测方程，和相应的线性静态状态估计算法。 - The model is continued by imposing a polar coordinate system on the moving reference frame.
通过把极坐标系作为该运动参照系而继续对模式进行积分。
