but depend mathematically on the given 
approximations. In this method, the first approxima- 
tions were calculated by contaminating the control 
point coordinates with random errors having a standard 
deviation of 15 meters. Then, the iterative calculation 
of the free network adjustment was performed by 
regarding the solutions obtained in the (i-1)th step as 
the approximations in the i-th step and replacing only 
the approximations of the control point coordinates by 
the rue values. Weights assigned to the control point 
coordinates must be very loose in the conventional free 
network adjustment. However,.he nine free network 
constraints (Equation 11) correspond to three control 
points in the orientation problem of satellite CCD 
line-scanner imagery, and they are too weak to obtain 
stable solutions. Thus, rather tight weights(one tenth 
of the unit weight) were given to the control points. 
The obtained results regarding the standard error of 
unit weight, the average internal error at the check 
» points and the average external error are shown in 
Table-2. From these tables the following characteris- 
tics may be extracted for the free network adjustment of 
satellite CCD line-scanner imagery: 
1) Unlike the conventional free network adjustment, the 
improvements in the internal accuracy are not very 
great, because comparatively tight weights were 
assigned to the control point coordinates. 
2) The improvements in the external precision are 
almost 10 percents in the case where the terrain is 
hilty. 
3) The solution sometimes diverges when the terrain is 
mountainous and the number of control points is 
small. 
CONCLUDING REMARKS 
In order to employ the orientation theory based on 
affine transformation for the analysis of satellite CCD 
line-scanner imagery, we must transform the 
central-perspective line images into affine ones. 
However, this image transformation cannot be 
performed without errors due to height differences in the 
terrain. Therefore, this paper presented an orientation 
approach of removing the image transformation errors 
by employing an iterative calculation. Further, the free 
network theory of affine line-scanner images has been 
constructed by finding nine linearly independent 
vectors.The proposed theories have been tested with 
simulated examples and have proved to be very effective 
for the analysis of satellite CCD line scanner imagery. 
REFERENCES 
/1/ Ebner. H. : Analysis of Covariance Matrices. 
Deutsche Geodaetische Kommission, Series B, 
No. 214, (1974). 
/2/^ Okamoto. A., Akamaru. S., Hasegawa. Y. : 
ORIENTATION THEORY FOR SATELLITE 
610 
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B3. Vienna 1996 
     
CCD LINE-SCANNER IMAGERY OF HILLY 
TERRAINS. International Archives of 
Photogrammetry and Remote Sensing, Vol. 29, 
Commission IIT, (1992) pp. 217-222.