现行的NURBS插补二阶预估公式不能保证插补过程中参数u的单调性，可能会出现插补方向反转，且其迭代过程在NURBS曲线尖角拐角处不一定收敛．为此，文中提出了一阶预估校正算法：采用一阶预估公式计算NURBS参数u的估计值，再迭代计算NURBS曲线的坐标点，直到满足插补精度为止．测试结果表明，文中算法可以保证插补过程中参数u的单调性，消除插补方向反转的现象，其速度精度与二阶预估公式相同，但迭代次数有所增加

As the current methods of two-order predictor in real-time NURBS interpolation process can not ensure the monotonicity of parameter u, the interpolation direction may reverse in some conditions, and the iterative interpolation process in the comer of NURBS curves is not always convergent. In order to solve these problems, this paper proposes a one-order predictor-corrector algorithm, in which a one-order prediction formula is used to calculate parameter u, and an iterative calculation is performed to obtain the coordinates of NURBS curves up till a satisfying interpolation precision. Test results show that the proposed algorithm ensures the monotonicity of parameter u in the interpolation process and eliminates the interpolation direction reverse, and that it is of a velocity precision as high as that of the two-order predictor though more iteration cycles are needed.