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At the third stage, the three optimization criteria (9a -9c) all reached minima, indicating that the set of 15 
significant orientation parameters has been determined. Their respective estimated values are: 7 =0.0 deg, 
M, =4.04 m/pixel; a, =256208.1 m, a4 2-041 m/s, a,220x10^7 m/s a,=—4.2x10$ m/s’, 
4,232x10 7 m* h227402723 m, h-92 mí b,--23. m/s, b,z43x107 mh, 
b,--3.0x10  m/s*; c, 2 7095.4 m, c, 20.018 m/s, c, -—4.5x10 ^ m/s). Notably, the insignificant 
parameters c, and c, are the polynomial coefficients used to model airplane altitude variations. Their 
deletion is justified because the real flight, at 7.0 km above ground, was intended to be level. 
4.2 Horizontal RMS-Errors 
In the preceding subsection, 5 points were withdrawn to serve as independent horizontal ground check points. 
In total, 6 cases were studied, each with 5 randomly located check points (McGwire, 1996). The X/Y root- 
mean-square (RMS) errors were based on the 30 check point coordinate differences. To make these horizontal 
positionings possible, every check-point terrain elevation Z; was treated as a known parameter, in the space 
intersection with Eqs. (1-3; 4). The positioning RMS results are listed in Table 2. 
Table 2 Horizontal position RMS errors 
  
X/East (m) Y/North (m) 
  
At 5x6 check points +53 + 4.2 
  
5. CONCLUDING REMARKS 
The space resection concerning an airborne SAR slant-range image is based on the radargrammetric 
(range/Doppler) equations, and is enhanced through parameter-significance testings. The applied parametric 
F-test statistic and the optimization criteria are given to demonstrate how their feasibility is achieved. The 
adaptive orientation parameter determination is a result of statistical inferences and hardly requires any human 
intervention. 
It is thinkable that, whenever parameter/measurement estimations are desired, the same optimality reasoning 
can be introduced into a data processing algorithm. Some related SAR-image processing themes are such as 
image matching for conjugate points, geocoding of spaceborne remote sensing imagery (Tannous and Pikeroen, 
1994), and integration of ancillary navigational data. 
ACKNOWLEDGMENTS 
The authors would like to thank the Council of Agriculture for supporting the 1993 SAR campaign, and the 
NSC Satellite Remote Sensing Laboratory for providing them the experimental image. 
REFERENCES 
Curlander, J. C., Kwok, R., Pang, S. S., 1987. A post-processing system for automated rectification and 
registration of spaceborne SAR imagery. International Journal of Remote Sensing, 8(4), pp. 621-638. 
Dowman, I., 1992. The geometry of SAR images for geocoding and stereo applications. International Journal of 
Remote Sensing, 13(9), pp. 1609-1617. 
  
International Archives of Photogrammetry and Remote Sensing. Vol. XXXIII, Part B1. Amsterdam 2000. 351