I am investigating different solutions for precise GNSS, specifically for doing photogrammetry and 3D reconstruction at correct scale using images from a standard phone tagged with precise (relative) positions. Photogrammetry and structure-from-motion algorithms have an inherent limtation that the reconstruction can only be determined up to an unknown scale factor, without any ground control points or camera positions.

I am looking to determine this scale based on precise GNSS measurements. Only relative positions in some arbitrary coordinate system are needed, for scaling the 3D reconstruction.

All the 3D reconstruction and image analysis stuff are in place, and in searching for dgps/rtk solutions I came across Reach and your great documentation and interesting products.

I am new to the world of precision GNSS, but I figure a possible solution could be the Reach RS base station combined with a Reach module coupled with a Android phone (rover). A few questions in this regard:

  • Is this overkill given that only relative coordinates are required. Is there anything simpler that achieves the same?
  • Is a standard Android GPS receiver (or some specific phone model) of any use combined with Reach RS/Reach modules for doing RTK?
  • The measurements are going to take place in a forest with varying degrees of Canopy - will this be a problem?

Thanks for any input!

Best regards,