I find that Mesh Lab is a lot easier to use for this than Blender. Then again, I think just about everything is easier to use than Blender. Open mesh life, drag your .obj into it and export as .dae. It's as simple as that.
I should note that I'm hardly an expert at mesh so others may have some better advise.
I should note that I'm hardly an expert at mesh so others may have some better advise.