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Figure | clearly indicate that assisted triangulation using | strip 
of simulated data can improve the check point RMS, but it is 
unable to reach a similar performance of the POS AV 510 
Direct Georeferencing data, especially in the vertical. However 
it is still acceptable for some lower accuracy requirement 
projects. Another conclusion that can be drawn from Figure 1 is 
that an increase in PPVG value can not improve the result of the 
Integrated Sensor Orientation. Thus, using more tie points in 
assisted triangulation will actually degrade the performance. To 
investigate this further, additional strips (2, 3 and 4) were used 
in the test. Figure 2 presents the ISO test when using 2 strips of 
simulated POS AV 310 data. 
Integrated Sensor Orientation using 2 Strips of Simulated Data 
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Figure 2. ISO Test Result when using 2 Strips of Simulated 
POS AV 310 Data 
From the above Figure, further improvement in both horizontal 
and vertical has been achieved. In fact the final accuracy 
achieved by running the Integrated Sensor Orientation on only 
2 strips of the simulated data is similar to the Direct 
Georeferencing performance of the POS AV 510 system (Table 
6.0), and increasing the number of strips in the adjustment does 
not significantly improve the results. Therefore the minimum 
requirement for assisted triangulation is only 2 strips. 
Regardless of the number of strips however, the more tie point 
that are used, in the assisted AT, the poorer the results are. 
l'urther investigation on this behaviour will be given later. 
5.2 SO Testing on POS AV 510 Data 
Running Integrated Sensor Orientation on the POS AV 510 
system will provide an insight into how much an improvement 
that can. be achieved when using a high end Direct 
Georeferencing system. The test configuration is the same as to 
run the test using the simulated data. Starting with using 1 strip 
of the POS AV 510 data, the result is shown in Figure 3. 
Integrated Sensor Orientation using 1 Strip of POS/AV 510 
Data 
  
  
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Figure 3. ISO Test Result when using | Strip of POS AV 510 
Data 
International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part BS. Istanbul 2004 
From Figure 3, it can be seen that running assisted triangulation 
using | strip of POS AV 510 data did not make any 
improvement in the achievable final 3D position accuracy 
(Table 6). Such triangulation in fact degrades the performance 
because of the lack of information in resolving the Omega angle. 
Solving this will requires a lot of ground control point in the 
strips, which is not practical for many applications. This 
explains why a high end DG system is required for single pass 
corridor flights, for example. In comparison, Figure 4 presents 
the result when 2 strips of POS AV 510 data is used. 
Integrated $ensor Orientation using 2 Strips of POS/AV 510 
Data 
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Figure 4. ISO test result using 2 Strips of POS AV 510 Data 
Even these results clearly indicates that only slight 
improvement can be achieved when running assisted 
triangulation on the POS AV 510 data. This can be explained 
by the fact that having a scale of 1:6000 and using a high end 
Direct Georeferencing system, this data set already has highly 
accurate 3D position accuracy, and it is especially well 
calibrated system, with boresight and datum shift error being 
minimized. Therefore, by applying Integrated Sensor 
Orientation on this dataset, insignificant improvement will be 
made. Notice that the test is performed without any ground 
control points. In a case where datum shift might exists in the 
project, running Integrated Sensor Orientation with 1-2 ground 
control points would improve the result. 
Similar to the simulated data, the ISO test on POS AV 510 data 
shows a trend that by including more automatic collected tie 
points into the assisted triangulation, the results are slightly 
degraded. This can be explained by the fact that by using more 
tie point in assisted triangulation will create more noise in the 
adjustment, as there is no guarantee that the tie point collection 
module can maintain the same level of accuracy all the time. 
This has been proved when reviewing the parallax for the tie 
and the check points through EO Analysis using the assisted 
triangulated EO derived parameters. Table 10 lists the parallax 
result from the ISO test on 4 strips of simulated data. 
  
PPVG Point Parallax (um) Model Parallax (um) 
  
  
  
  
  
  
  
Value | Max Value RMS Max Value RMS 
2 23.2 S2 27 4.3 
4 27.3 5.5 7.5 4.4 
6 28.3 5.4 6.3 4.2 
8 29.5 5.4 6 4.2 
  
  
  
  
Table 10. Parallax Result on EO Analysis after running 
Assisted-Triangulation on 4 Strips of Simulated POS AV 310 
Data