Are they comparing live data with Street view data to ensure accuracy or is it just simple direction overlays through GPS? What algorithm is best for comparing

Are they comparing live data with Street view data to ensure accuracy or is it just simple direction overlays through GPS? What algorithm is best for comparing images in 3D space while taking into account of differences due to littering, vehicles, street signs etc.? Also this is a great way for automated outsourced Street view data gathering. Would need a strong image stabilization algorithm but nothing a big enough neural network can't handle, in theory at least.