Article about what dual-frequency GPS is: https://www.zdnet.com/article/what-is-l5-precision-dual-freq...

It says that GPS has added a new band (L5) that works better indoors. Combining it with traditional L1 gives better results. L5 is not fully deployed.

My Google Pixel 6 can already do this. I can see L5 and L1 GPS satellites at the same time right now. I can also see a lot of other systems ones.

MilaM

How is the positioning accuracy outdoors?

My iPhone 13 is rather disappointing in this regard. Even in my garden, with a clear sky, Maps.app will show my location at least 5 m off my actual position.

orev

5m is within the design spec of L1 GPS, so you’re getting it as designed. GPS was never designed to be mm level accurate. The new L5 frequency aims for 30cm accuracy.

joecool1029

It is possible on quite a few modern Android phones to access raw receiver data and do post-processing using a rinet file to get mm-level accuracy. It's a little over my head since this isn't my industry. One of Google's more obscure Android apps to be used with it: https://play.google.com/store/apps/details?id=com.google.and...

GPSTest also carries some logging functionality to do the same: https://github.com/barbeau/gpstest