Just a thought.. Assuming that those interested in PilotAware are a bit tech savvy, I would think many are feeding a GPS signal into their transponder so they too are transmitting their position through ADS-B Extended Squitter. That may well be an independed GPS signal of much higher quality than the dongle/rosetta can provide.
If this is the case, then I'd think PilotAware can use the plane's own ADS-B signal to establish position, even if the GPS dongle fails to provide a decent fix. You already need to fill in your 24-bit identifier anyway, so when you receive your own transponder, it will have your exact position included.
This way you may have redundancy in GPS location.
What do you think?