中文摘要：

为了研究位场向下延拓的迭代法的扩边方法,分析位场向下延拓的迭代法的波数域因子Φn与单位脉冲函数的关系,在空间域迭代法实质上是一系列单位脉冲函数在系统F-1（Φn）作用下的线性代数和.理论分析得出扩边点数适当即可,大深度延拓相对需要扩更多的点,扩边的好坏会影响到延拓结果的精度,并使用理论模型进行检验.同时也利用理论模型试验对区域场扩边、三方向扩边、余弦扩边和最小曲率扩边进行对比,结果表明,最小曲率扩边的延拓结果精度是其他扩边的延拓结果精度1～3倍以上,效果好.

英文摘要：

In order to study the extending methods of iteration of downward continuation in potential field, this paper concerned the iterative method of the downward continuation and analyzed the relationship between wave domain factor , and unit pulse function. In spatial domain, iterative method is essentially linear algebraic sum of a series of unit pulse responses. It is applicable if appropriate number of extending points is attained by theoretical analysis. As large-depth continuation method needs more extending points, the quality of expanding has effects on the accuracy. This paper compared four extending methods ： extending regional field , extending three directions, extending cosine, extending minimum curvature. According to theoretical models test, this study points out that extending minimum curvature method has the better result and accuracy of this method is as one to three times as any other three methods.