Took my Spark out for a flight mid day yesterday, after 5 or 6 successful flights the night before. This time it had me do several updates, which went well. When i put the drone up it would get to about 75 feet and it would say no GPS and then start drifting away. Once it was brought down in elevation, GPS would be back on. Is the GPS limited to the wireless range? Which doesnt sound right, but cant quite figure it out, everything reads as A OK,,, appreciate the help!    Cheers Jason

Gps is received by GPS receiver in your AC it's not affected by wifi , if it's not receiving gps it's usually because something is blocking it. It can be as simple as a very cloudy day over hanging trees flying under bridges.
So it's strange why you are getting gps at low altitude and loosing when you ascend, opposite should be happening, maybe try it in another area, also remember the best reading for gps on your telemetry is the graph beside where it shows number of sats, 4/5 is good to very good.

If problem persists it may be your receiver.