(1) AL » A. AX n»m 
where 
AL=L- L(X9) : observed minus computed observations; 
AX : unknown elements; 
A : design-matrix giving the functional relations between the unknown elements 
and the AL-values; 
n : number of observations; 
m : number of unknown elements. 
The covariance matrix of AL is denoted as Q, with variance factor c; , hence 
(2) y - $.Q, 
The weight matrix of AL is denoted as 
(9 P-d 
The general least-squares solution of (1) is: 
(4) x = Xx° + (A'paytatau 
where 
O | 
X' : approximate values for all unknown elements; 
: : : t -1 
X : a solution for the unknown elements with covariance matrix i. = (A PA) 
- 396 =