Satellite signal reflections from buildings in NYC can be a challenge for a GPS or almost any wireless device. Perhaps more so the N810's GPS. A-GPS won't overcome that kind of problem. I've found that A-GPS does help in Fresno CA but we don't do lots of tall buildings here. We all wish that Nokia had made a different choice for GPS chip in this device. You may not find this acceptable but a bluetooth GPS receiver with the Sirf-III chip would likely give you the performance you are seeking.