Legend has it that medieval Chinese warriors (used manned kites to survey enemy troops,a technique anticipating modern aerial surveillance.)我认为 surveying 改为to survey 比较好.
后面a technique anticipating.按照意思,a technique是对using manned kites to survey.的同位
这样的语法不算错
其实 也可以 看作 非限制性定语 补充说明 前面的Chinese warriors (used manned kites to survey enemy troops这句话 = ,which was a technique anticipating modern aerial surveillance.)