Creating a new earth connection for grounding an outlet

I have an older outlet in the house that is not grounded. Running a ground wire back to the panel is not easy. But the outlet is on an exterior wall that is quite close to the dirt outside. Can I sink a copper pipe into the dirt, drill a hole in the wall, and attach a ground wire from the outlet to this new ground connection outside? Is that as good as a normal ground connection at the panel?