138 
TSX 
GPS 
Difference 
X (m) 
392130.3 
392136.2 
-5.9 
Y(m) 
3948962.3 
3948962.2 
0.1 
Corner reflector 2 
Figure3. Four validation points of Tsukuba site. 
3.3 Evaluation using the digital map 
The pixel location accuracy of the mountain area was evaluated 
using digital map at the scale of 2500 because the pixel location 
accuracy of the reference data was better than 2 m. Table 10 
shows the specification of the used data. The study sites were 
Toy a (Hokkaido prefecture) for SpotLight and Kagawa 
(Kagawa prefecture) for StripMap. Figure 4 shows the part of 
TerraSAR-X image and validation points of both sites. 
More than 20 validation points were extracted mainly from the 
intersections of the roads (Fig. 5). The recorded position of 
these points on TerraSAR-X images were compared with those 
from digital map. 
TSX 
GPS 
Difference 
X (m) 
392146.3 
392151.1 
-4.8 
Y(m) 
3948963.3 
3948963.2 
0.1 
Table 8. Comparison of the location accuracy of the EEC 
product by different looking direction. 
3.2.4 Pixel location accuracy comparison for Tsukuba 
site: The validation of the pixel location accuracy for some 
points is effective to evaluate the deviation of the errors 
spatially. Table 9 shows the comparison of location accuracy of 
EEC product in Tsukuba site. Four comer reflectors were set at 
the flat park or parking lots (Fig. 3). The used orbit type was 
science orbit. 
Toya 
Kagawa 
Acquisition Date 
21th Oct. 2007 
4th Jan. 2008 
Mode 
SL 
SM 
Incidence Angle 
31.3 
35.3 
Orbit 
Descending 
Descending 
Scene Center 
42.6 N, 140.8 E 
34.1 N, 134.0 E 
Table 10. Specification of used TerraSAR-X data. 
The pixel location accuracy is better than 1 m for both X and Y 
except the X of point 1. The deviation for the points is found to 
be small. 
Point 1 
Table 9. Comparison of the location accuracy of 4 points in 
Tsukuba site. 
(a) Toya 
(b) Kagawa 
Figure 4. TerraSAR-X EEC product of Toya and Kagawa. 
Points show the validation points for each site.