40 km
ngth
gth
Fig. 11 demonstrates the single hight errors O7 of one strip at the
axis and the borders. The strip length is 84 km“ and absolutely
oriented by only four control points in the corner of the strip. The
dashed line represents the theoretical error in case of error free
orientation parameters.
Flight altitude h 8.0 km
oz;m Strip length 85.0 km
b Strip width 12.0 km
| Update point interval DOR 0.3 km
Hight error of the Focal length c 100.0 mm
1.4 — : borders of the strip Image error 09 + 5.0 um
Hight error of
124 the strip axis Pad
: es mTuR LIGAS M 0. 7 . 4. NY. sl TT ET TQ .
j —— Y descente jad rimes een te S PL X
1 .0 1 == — \ Py . int 777 -— Kan gt Sal ea” A X .
\ Z. aae Nl ;
0.8 - 7 -—
a, SE SET
0.6 -| \ : L
\ Theoretical error limit
0.4—
0.2 —
Middle of the strip
! 1 i | | i | i i | i
4 8 12 16 20 24 28 32 36 40 44 km
Strip coordinate X
T
1 2 3 4 5 6 7 8 9 b
-T
À
-
-
-
-
E
-
—
Figure 11. DEM-hight errors of a long DPS strip
5. APPLICATION OF THE DPS-PRINCIPLE TO OPTO-MECHANICAL SCANNERS
The DPS-principle is not restricted to push-broom scanners, it may be
applied to opto-mechanical or other scanners too. In this case three
scan planes must be generated by rotating mirrors or other suitable
means and instead of the image coordinates the directions of the
image rays to the correlated image points are the observations to be
adjusted. This requires the measurement of the scanning rays and their
synchronisation with the recorded image data. The compilation and mean
square adjustment is the same as for the three line push-broom scanner.
6. CONCLUSIONS
In connection with the correlation process, which is an integral part
of the system, the DPS can be developed to a very accurate and efficient
method for topographic and thematic map production in a wide range of
scales, especially for large areas.
The main result of the model simulation is the high stability and near-
ly constant accuracy over the whole strip model.
The DPS may be applied in aircraft or spacecraft. The stereo camera can
be combined with spectral modules whose sensor lines are parallel to
the central line B of the three line camera. Orthophotos and stereo
orthophotos can be produced and form the base for various geometrical
and spectral evaluations.
= 355 -
