The purpose of the GPS is to give the computer
some of the information it needs to compute its model of the sky, the other being the position of 2 (or more) stars during alignment.
The Starsense eliminates that...it zips around the sky snapping pics of snippets of the sky and deciphering what the stars are for itself and computing its model of the sky that way. It would have to compute the location and time as part of that determination based on where it finds the stars, otherwise it wouldn't be able to goto or track correctly.
In the interests of science, I would try it with just the Starsense and without the GPS to confirm that