The Intel national Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. Vol. XXXVII. Part B4. Beijing 2008 
95 
GPS Shift/Drift Correction and INS Shift/Drift Correction 
check box(See Figure 2), then Click Ok, press Compute to do 
block adjustment, and, as desired, monitor the progress of the 
computation in the Solution Progress dialog box. If there is 
antenna height correction, we will also select Antenna Offsets, 
and input X, Y, Z correction parameters. 
Adjustment Mode 
r g elative 
; (• Absolute 
Adjustment Parameters 
[✓ Enable Precision Computation 
f~ Enable Error Detection 
P Chiude Manual 
\ r~ On tdr I 
JSl 
Camera Calibration Settings 
f* Camera Catenation [ 
Given EO / GPS / INS Settings 
p EnableÉivenEO/GPS 
Antenna Offsets 
p GPS Shift/Drift Correction 
p INS Shift/Drift Correctiorl 
Residual Filter Options 
f~ Auto Threshold 
f~ 2D {mage Pont Residuals 
r~ X> Qbiect Point Residuals. 
Display Precision Settings 
Image Decimal Precision fT 
Object Decimal Precision: |3 
Point Fier Options 
& Tie Points 
Î7 Pass Points 
P Control / Check Pomts 
Number erf Rays Fiter: 
Min: |0 Metcliw“ 
U.inSWD* 
r p OOT 
CacnMaID I On 1 FociLength . [Ön I PPACXSldD, [pPACYSId .. 1 
597029042 011 0.030 nmo nn„. 
r Sell - Calbtetion j~ 
r. r 
r r 
r 5 ri 
r r . 
I Enabled Additional Paramele«« 
N 
Camera ID 
1 X Offset 
1 Y onset 
1 Z onset 
597029042 
0.000 
0.000 
0.000 
Figure 2 
orientation on the models, by block ID, or by model ID. Click 
Compute, and review the results when they are displayed. 
Finally, we use Export command in Translators menu to export 
PATB > EO and Control reports. 
p Photo Statistics 
p Object Statistics 
p Point Statistics 
p Exterior Orientation 
p GPS Statistics 
p INS Statistics 
T iSelf-Caiibration Statistics! 
Help 
Cancel 
Figure 3 
4. CONCLUSION 
Through the aerotriangulation of Spanish project, we are more 
skillful with ISAT sofware. We think it has good reliability, 
quality and function. It can work for large projects more 
conveniently and effectively. Its points matching can reduce a 
lot of manual points selection work. With GPS\INS aid, we need 
less ground control points, so the field work has been reduced a 
lot too. Furthermore, DMC images do not need to be scanned, it 
also increase the efficiency of aerotriangulation. 
When computation completes, we can analyze the triangulation 
results, view the summary statistics to check whether the 
solution is satisfactory or not. Check sigma value, Root Mean 
Squares(RMS) errors of control and check points, maximum 
control point residuals, and mean standard deviation values of 
the object point coordinates and EO parameters, and check if 
the drift value between exterior orientation and input GPS\INS 
is within accuracy. If there are still big residual error ground 
control points, we can written down the point label and use 
Point Measurement command(ISAT menu) or Multiphoto 
command(Orientations menu) to re-measure the points in stereo. 
After we adjust the ground control points, we can re-do bundle 
adjustment till the result reaches the accuracy requirement. This 
step will Commit the bundle adjustment results to the project 
files by clicking OK on the Photo Triangulation Results dialog 
box. This writes the computed EO parameters to the Photo file 
and the adjusted tie/pass points coordinates to the project Triang 
file. The absolute orientation accuracy for this project is Max 
Rms X,Y^0.1m; Z^O.lm. 
3.8 Submission of final result 
After the relative orientation and absolute orientation meet the 
accuracy requirement, we can click Reports in Photo 
Triangulation Results dialog box, a PhotoT Reports will come 
out, See Figure 3. The computed EO parameters has been 
written into Photo file when we do block adjustment; Select the 
Densify command(Orientations menu, Photo Triangulation 
submenu) to open the Densification dialog box, click OK to 
densify control procedure and this process writes the calculated 
ground coordinates of the tie/pass points from the Triang file to 
the Control file. Select the Bulk Orientation command 
(Orientations menu, Photo Triangulation submenu) to open the 
Bulk Orientation dialog box. At a minimum, select the Relative 
Orientation and Absolute Orientation check boxes. Select 
photos and models to perform relative orientation and absolute 
In high-speed developing information society, satellite 
navigation system has been widely used and it can provide high 
precision service. GPS has the function of navigation, 
positioning, timing, and measuring etc. Besides, with the 
development of aerophotography technology, there will be more 
and more DMC digital images with air-borne GPS and INS 
which can takes place of aerophotograph films and scanners. 
We believe ISAT will be used more and more widely. 
REFERENCES 
Chen Xiaoming, 1992. Theory and Application of High 
Precision GPS Dynamic Positioning:[Doctoral Thesis]. Wuhan: 
Wuhan Science and Technology University of Surveying and 
Mapping, 1997 
Li Deren, Zheng Zhaobao. Analytical Photogrammetry. 
Beijing: Surveying Publishing House, 
Users’ Manual of ISAT 
Wang Huinan. 2003. Principle and Applications of GPS 
Navigation..Beijing:Science Publishing House 
Yuan Xiuxiao, 2001. Theory and Application of 
Aerotriangulation with GPS Aid. Beijing: Surveying Publishing 
House 
ACKNOWLEDGEMENTS 
During writing this paper, Mr. Bai Zhigang gave us the 
constructive support, and Ms.Peilei made the translation for this 
article. Here we would like to express our hearfelt appreciation 
to them.