To confirm the health of the GPS on the Cortex M1 there are several views to confirm that the GPS is working correctly.
On the M1 hub itself the GPS icon will have these indications:
Solid Orange when acquiring a GPS fix
Solid Green - flashing green momentarily when acquired and then returns to solid after a few seconds
Solid Red- GPS Antenna short detected. It may also be a system error. Contact support.
To check the GPS health on the handset and with the Onboard app (Android). iOS is very similar- tap the GPS icon and the GPS status page comes up
Tap the GPS icon on the top of the banner
This will bring up the satellites in view and and the type of satellite, and whether active or inactive. You see the symbols used by tapping the ? .
You can also make changes to the GPS options by tapping the gear icon.
To get to the settings on iOS
Menu>Config>Hub setup>Systems>GPS
To decide the best setup for your vessel, check this linked article.