Regarding the satellite signal bar, the Garmin aera manual states:
GPS Status can be helpful in troubleshooting weak (or missing) signal levels due to poor satellite coverage or installation problems. As the GPS receiver locks onto satellites, a signal strength bar is displayed for each satellite in view, with the appropriate satellite PRN number (01-32 or 33-64 for WAAS) below each bar. The progress of satellite acquisition is shown in three stages, as indicated by signal bar appearance:
- No bar—Receiver is looking for the indicated satellite
- Gray bar—Receiver has collected the necessary data and the satellite signal can be used
- Green bar—Satellite is being used for the GPS solution
Since the EGNOS signal is merely a corrective augmentation, I can't really see how it is used as a source for the GPS solution itself as the vehicle is in a geostationary location. The manual also states that the Receiver Status field gives the following information concerning SBAS corrections:
When the receiver is in the process of acquiring a 3D differential GPS solution, "3D GPS Location" is indicated as the solution until the 3D differential fix has finished acquisition.
“3D Differential” appears when you are receiving DGPS corrections in 3D mode.