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.