On the base station, the LED lights solid white when the module is powered via USB.
Red Safety LED
This LED is located next to the module's button.
When installed on Alta X, the LED indicates arm status
Double-blinking red: aircraft is powered up, but not armed
Solid red: Aircraft is armed
On the base station, the safety LED is used to indicate bootloader mode (used for firmware updates). The LED will briefly blink when the module is first powered up via USB, and will stay solid red when the module is in bootloader mode.
Alta QGroundControl GUI
When the base station is plugged into your computer, Alta QGC will display two GPS-related indicators:
Aircraft GPS: This is the same dialog as with normal GPS, and it indicates:
GPS Count: The number of satellites seen by the Alta
GPS Lock: The type of lock.
3D GPS = normal (non-RTK)
3D RTK GPS Lock (fixed) = RTK lock, best precision
3D RTK GPS Lock (floating) is pretty much equivalent to 3D GPS
2D GPS is equivalent to not having GPS (ie, it must be at least 3D to be of any use to the aircraft)
HDOP: Horizontal Dilution of Precision: A measure of how good the horizontal position is (lower is better)
VDOP: Vertical Dilution of Precision: A measure of how good the vertical position is (lower is better)
Course over ground: Direction of flight path. Only valid when the aircraft is moving
Aircraft GPS Status
RTK Base Station: This icon and window indicates the status of the base station
The RTK icon color indicates status:
Red or Grey: Not connected, no base station GPS detected
Blue: Survey-in initializing
Yellow: Survey-in active
White: Survey-in complete, base station is sending RTK corrections
GPS Status (inside the window when the icon is clicked) indicates the Survey-in Status
Not Connected: No base station GPS detected
Survey-in in process
Survey-in complete: Base station is providing RTK corrections, aircraft can compute RTK lock
Accuracy: Current accuracy of position estimate. Accuracy number should decrease during survey-in, and will remain the same after survey in is complete
Satellites: Number of satellites observed by the ground station. This number might not match the aircraft's number
Duration: Duration of survey-in. Number will increase until survey-in completes