"How can I do this?"

This Wikipedia pages has a lot of math I don't understand:

https://en.wikipedia.org/wiki/Dilution_of_precision_(GPS)

but the two pictures speak to the issue. "DOP" depends greatly on the angle from your location to satellites in view. The example in the canyon show the effect of what I would call narrow angles. For altitude/elevation, low DOP depends more on getting signal from satellites whose angle is closer to a tangent to earth curvature, so lower-lying features like hills and trees make it hard to get signals from stallites that can provide a flatter geometry. Airplanes flying at altitude don't have the same problem of acquiring and keeping enough satellites to provide low VDOP.

This doesn't answer the question (and I made some of this up) but there may not be a good answer. No free lunch as they say.