You may have problems with the antenna "seeing" the satellites. It might work right next to the windshield. Our mini doesn't work well in forest or canyons, and while driving doesn't seem to find a location (perhaps because we are moving too fast). But once it knows where you are, it seems to keep connected to the GPS's better.
We have the minimum option where tracking is too expensive to use, so just send out "we are here" presets a bit past critical junctions. That way our ground team knows where to start looking.
I heard the latest version uses more satellites, and may work better. Frankly, the mini we have is a bit disappointing. Works great when it sees a lot of sky though!