在确定多个未知量的最或然值时，选择它们之间不存在任何条件关系的独立量作为未知量组成用未知量表达测量的函数关系、列出误差方程式，按最小二乘法原理求得未知量的最或然值的平差方法。-In determining the most probable value of more than one unknown quantity, there is no choice between them, the amount of any of the conditions independent relatio

最小二乘法，用于数据预处理，消除趋势项，减少误差-A time domain modal parameter identification, can be measured data get the structure frequency and damping ratio and mode shapes