Version 4 (modified by mggr, 12 years ago) (diff)

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Boresight calibration

Copy of email to Andrew Wilson (wikise later)

As I understand it, a calibration flight passes over CEH several times in opposing directions.

The idea is to process the data sets and overlay them, then adjust the PRH numbers until things line up exactly over the calibration points (and hopefully everywhere else).

Because the flights are in opposing directions, one can "focus" the points inwards towards convergence by using estimates of distance and direction of flight/direction to convergence.

Additionally, you have the positions of the calibration points exactly measured (by placing a GPS unit on them for several hours at different times of day) and also have a base station in the flight line (in the CEH tower?).  Once the calibration is correct, the mapped position of these points should match your recorded coordinates (if this is correct, how accurate do you normally get this?).

Obviously, this would need to be done for each sensor (ATM, CASI, Hawk & Eagle).  The LIDAR correction is handled by Cambridge?

Also, which tools do you normally use?  I'm presuming you mostly use Imagine with the GeoTIFFs? 

2007 point locations and notes

Calibration zone:

  • CEH Monks Wood
  • Approximate location:
    • ETRS-89 (WGS-84) XYZ: 3899843.8284m, -16318.7154m, 5030129.9893m
      • Longitude: 0 degrees, 14 minutes, 13.56 seconds (
      • Latitude: 52 degrees, 28 minutes, 28.43 seconds
    • OS Grid (OSGB-36): 519857.522, 279414.596
Point ETRS 89 (WGS 84) Pos Qlty Hgt Qlty Pos+Hgt Qlty OS Grid (OSGB 36)
Id. X Y Z Quality Quality Quality E N H
1 3899990.9122 -16767.0766 5030016.9027 0.0096 0.0146 0.0175 519414.561 279216.784 44.499
2 3899983.7474 -16573.9922 5030023.1466 0.0049 0.0063 0.0080 519607.267 279231.601 44.576
3 3899977.7336 -16320.1818 5030025.6952 0.0120 0.0178 0.0214 519860.745 279244.932 42.279
4 3899843.8284 -16318.7154 5030129.9893 0.0035 0.0069 0.0077 519857.522 279414.596 43.201
5 3899738.4140 -16316.4996 5030210.5789 0.0017 0.0020 0.0027 519856.068 279547.267 42.728
6 3899731.4446 -16091.6668 5030214.0582 0.0002 0.0005 0.0006 520080.550 279561.121 40.668
7 3899489.7218 -16085.1161 5030392.4048 0.0040 0.0062 0.0074 520078.781 279861.452 34.480

Please note: point 25 on the previous survey is the same point as point 7 on this survey. As point 7 is an average solution derived from four other points + a temporary base station the result above is a far better solution..

Monkswood calibration targets (annotated)

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