International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part Bl. Istanbul 2004
regular grid, a regridding interpolation processing is necessary.
[Eineder M., 2003]
4. RESULTS
Three groups of terrain data are randomly generated with fBm
model, and each comprises three types of terrain, the flat region
(c23,H 20.9 ) the hill region ( &6 210,7 «0.6 ) and
mountain region (c — 30, H = 0.3). In the visual sense, these
simulated terrain models are obviously different in terms of
roughness and shape. The simulation results are shown in
Figure 2.
In the study case, the orbit parameters of a pair of ERS-1/2
tandem data are assumed and a location for synthetic DEM in
common area of two SAR images is assigned. Here the
geographic location of left-low corner point of synthetic DEM
is (30.2500^ , 111.625" ) and the space of pixels is 1.5 arc-
second (about 45 meter in ground). The difference of the
elevation can change arbitrarily. Other parameters for the
simulation are given in Table 1.
Table 1. The simulation parameters
Item Parameters
DEM pixel spacing 45 m X45 m
DEM data size 256 X 256
LAT: 30.2500° -30.3567°
LON: 111.625° -111.7317°
ERS-1 orbit = 25070
ERS-2 orbit = 5397
FRAME = 2997
1996-5-1/2
DEM location
Orbit of ERS-1/2
Imagery time of ERS-1/2
PRF 1679. 902 Hz
Wavelength 0. 05667 m
azimuth X range pixel spacing | 3. 985 m X 7. 904 m
Nearest slant range 829. 213 km
Parallel and normal
; ; Br 52m B,= 102m
| components of the baseline
Master to Slave Warp Matrix
59979 —000000 1.00027
[ACA 1.00001 T
We choose the synthetic hill region (c =10,H = 0.6) to test
the interferogram simulation algorithm with different elevation
differences. Assume the look angle is 23 degree for ERS data. It
is found that the height ambiguity approximates 90.1m when
the normal baseline equals tol02m. Figure 3(a) shows the
synthetic DEM with the elevation changes from 16m to 536m.
Figure 3(b) gives the corresponding interferogram after
removing the flat phase. lt is seen that the synthetic
interferogram can well reveal the variety of DEM. Figures 3(c)
and (d) give another example with the elevation changes from
263m to 367m.
5. CONCULSION
- An interferogram simulator combining DEM simulation and
interferometric phase simulation has been developed and tested
94
with real orbit parameters and geometry model. It is a good
assistant tool not only for validaition of phase-to-height
converion and geocoding processing, but also for D-InSAR
processing.
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IEEE Trans. on Geoscience and Remote Sensing, Vol. GE-20,
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Eineder M., 2003, “Efficient Simulation of SAR Interferograms
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Franceschetti G., lodice A., Migliaccio M. and Riccio D., 1998,
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Acknowledgements
The present work is supported by 863 programs
(2001AA 135070) of the Ministry of Science and Technology,
China. The authors would like to express their gratitude to Prof.
Zhong LIU for his help.
Internationa
