@Tony Campos yeah what you're describing is pretty much textbook urban canyon behavior — nothing wrong with your module, it's a physics problem. When you've got buildings on both sides, you're losing a big chunk of your visible sky, so the module is working with fewer satellites and worse geometry (high PDOP), and on top of that you're getting multipath where signals bounce off building faces before they hit the antenna, which is what really kills that last meter of accuracy.
The 18Hz fix rate actually helps here more than people realize — at that update speed the module can track position drift in real time rather than jumping, so even if absolute accuracy is degraded you're getting a smoother, more usable position trace than you would with a slower module. For the worst intersections, if you're logging data rather than needing real-time precision, you can do some post-processing filtering to clean up the multipath spikes.
One thing worth trying if you haven't already — antenna placement matters a lot in canyons. Even a few centimeters higher or tilted differently can meaningfully change which satellites you're acquiring. If you're mounting this on a drone or vehicle, getting the antenna as high and unobstructed as possible (away from metal structures, batteries, motors) makes a real difference.
