Configuring Ground Mode
Written by Fezile Mojapelo
Updated at December 8th, 2025
Table of Contents
The Griffin Air features ‘Ground Mode’, which is an advanced detection mechanism for determining whether a device is in a flight or not. This can be useful for determining when the device should go into a dormant mode so that it doesn't waste power or transgress air safety rules by attempting communication during flight.
‘Ground Mode’ is equivalent to 'normal' operation. That is, operation of the device when it is on the ground and not in flight. Therefore, by default, the device is said to be in ‘Ground Mode'.
When the device is detected to be in flight, it is said to have EXITED ‘Ground Mode’. In this state, the device goes into a sleep mode until it detects that it is no longer in flight. It may still log data and scan for Bluetooth tags in this state, but it will not perform uploads.
Distinction between Ground Mode and Flight Mode
Although the feature is called ‘Ground Mode', this is simply to distinguish its behaviour from the existing ‘Flight Mode’ feature on Digital Matter devices, which is much less complicated as it is either geofence-triggered or enabled via an async message. ‘Ground Mode' and ‘Flight Mode’ are independent features, but they both achieve the same goal: suppression of cellular communication when the device is deemed to be in-flight.
Configuration
The triggers for exiting Ground Mode are accelerometer jostling and the barometer (whichever configuration the user has set in the System Parameters for it to trigger). Once one of these triggers becomes active, the device will either exit Ground Mode straight away, or it will first attempt to get a GPS fix if the GPS Fix Period is non-zero.
Note
Ground Mode detection is disabled by default. It needs to be explicitly enabled.
The GPS fix is used as a temporary suppressor, whereby the device will not exit Ground Mode if it is able to get a fix and determines that the speed is below the configured threshold (meaning that the device is actually not in-flight). The GPS Fix Period determines how often the device checks for fixes if it is deemed to be in-flight as a failsafe to lingering triggers.
Sensor Logic: By default, this is ‘EITHER’. This means that either accelerometer jostling, or a barometer trigger can cause the device to deem itself to be in flight and exit Ground Mode. Setting this to ‘BOTH’ is a stricter condition, whereby both triggers are required for the device to exit Ground Mode.
Accelerometer Trigger End Duration: If the device registers a jostle, it will set the accelerometer trigger to be true for this duration. This means that if a device registers movement and then does not experience any movement thereafter, the trigger will still be held for this duration. If, at the end of this period, there is still movement, the trigger will be prolonged.
Barometer Trigger End Duration: Similar to the Accelerometer Trigger End Duration, but for the barometer.
GPS Fix Period: As described in the overview, this is how often the device attempts a GPS fix while the device is in a flight. This behaviour can be disabled for additional power saving, but it is not recommended from a failsafe perspective.
Speed Threshold: This is the speed limit that the device must adhere to if it gets a successful GPS fix while the flight triggers are active in order to suppress the flight condition temporarily and allow uploads again.
Flight Detection
Flight detection relies on the barometer module and accelerometer configuration.
This means that Barometer Mode needs to be enabled and configured for an appropriate trigger together with the accelerometer and jostle filter - see Accelerometer Wakeup Thresholds.
Threshold Configuration example
Below is an example of a pressure profile showing barometer readings of the Griffin Air during a flight. The departure and arrival destination both have altitudes near sea-level. The analogue value is pressure logged in hectopascals against UTC time.
Given the pressure profile above, two barometer modes could be used to detect the flight condition:
Relative Low Threshold: An initial pressure decrease sets the trigger, and a final pressure increase clears the trigger
Absolute Low Threshold: Once the pressure goes below a given absolute threshold, the trigger is set. Upon increasing above the threshold, the trigger is cleared.
Important Considerations
Ground pressure is not always close to 1000hPa and the rate at which the pressure changes is important for determining the Relative Low Threshold. This means that testing is important to determine the most effective configuration to cater for variations in altitude.
Ground Mode System Parameters
A potential system parameter configuration for an effective accelerometer trigger and general Ground Mode setup is as follows:
Relative Low Threshold Parameter Choice
Absolute Low Threshold Parameter Choice
Note
An absolute pressure threshold of 800hPa is only applicable for devices that travel to airports with altitude below ~2000m
