I'm a little confused on this topic. I need to put 2 SAR images into same coordinate grid.

In ESA SNAP tool, there are 2 options:

• coregistration: Radar->Coregistration->Coregistration
• collocation: Raster->Geometric Operations->Collocation

SAR images are from COSMO-SKYMED and ALOS1 missions.

What is the conceptual difference between collocation and coregistration?