I think the accuracy should be fine, cell phones typically have a GPS accuracy of 5-10 m. The problem is that you won't be able to rely on it. You probably wo

I think the accuracy should be fine, cell phones typically have a GPS accuracy of 5-10 m. The problem is that you won't be able to rely on it. You probably won't have any GPS signal at all in an underground parking garage, and even in an above ground parking deck you will likely have poor or no signal due to being surrounded by steel and concrete.