Additional adjustment parameters for airborne photo-centre coordinates

[SP74]

Hi,

We fly the vast majority of our projects with survey grade GPS using PPK method.  Whilst ee may have our GCPs and airborne photocentre coordinates in the same datum/map projection, they have been derived off different origins.  For example, a mine-site survey may have the airborne photocentres derived from a CORS network. Meanwhile the mine surveyors have tied their GCPs into a existing geodetic network, potentially derived many years ago using optical survey methods.  In remote areas, there may be decimetre level differences between these datums, most notably in elevation.

To combat this some additional parameters in the block adjustment are introduced to allow the translation (and/or rotation & scale) of the airborne data to fit the GCPs.  Block adjustment applications such as PATB & ORIMA allow solution of such parameters, and it  doing so may increase the solution accuracy for Photoscan.

At the moment the GCPs are used as check points to determine the magnitude of any systematic translations, which are then manually applied using excel to the airborne photocentre coordinates.

Best regards,

Stu Paisley.