How to align a satellite raster layer and UAV raster layer with high accuracy?

[ScarletMaguire]

I have a World-View-3 satellite image of a specific scene and I also have a UAV image of the same scene. However, when I overlay them they do not spatially 'match up' with high accuracy. Interestingly, the degree to which the images do not match up changes at different points in the image; for example, in some parts of the scene there is a 14m difference between the same point in each image, in other parts of the scene the difference is only 2-3m. This suggests that perhaps one of the images is distorted to an extent, but I have been unable to establish which image.

I have tried several things to make them align, with no success: I ensured the geographic and projected coordinate systems are the same; I tried using Ground Control points (which made no difference even after making 12 points); I tried using the Project Raster tool to re-project one of the raster layers to match the other; I have also experimented with the Reproject tool. I am trying to achieve around a 1m accuracy.

I must mention that when the UAV image was collected, a RTK station was not used, which undoubtedly would have affected the spatial accuracy of the image.

Any advice on how I can make these layers align would be greatly appreciated. Thank you in advance.

[DanPatterson]

You don't specify which projected coordinate system you were using (anything but web mercator, I hope)

If you were doing any projection of the raster, what cell size projection method did you specify?

Cell Size Projection Method (Environment setting)—ArcGIS Pro | Documentation

How the Cell Size Projection Method environment setting works—ArcGIS Pro | Documentation

What is the extent of the rasters and its coordinate systems and datums?

[ScarletMaguire]

Thanks for your reply. The projected coordinate system for both layers is WGS 1984 UTM ZONE 30N, while the geographic coordinate system for both layers is WGS 1984. The satellite raster covers an area of 25 kmsq, while the UAV layer covers a smaller area of 2km sq.

I did not consider the importance of cell size projection, I just ran the tools and left those parameters as default. I will read the documentation you suggested and see if it helps.

[DanPatterson]

I would begin with subsampling the larger raster to the same extent as the smaller raster before doing any projection so that you set up the projection properties for cell size etc equally