Failsafe: add timer for non gps fused position estimates

[perrrre]

Solved Problem

Configured PX4 to enter controlled descent after (parameterized delay of) x s of dead reckoning.

Solution

• Add parameter COM_DR_TOUT_T to specify time based threshold to safety action
• Add parameter COM_DR_TOUT_ACT to select safety action after the timeout
• Add failsafe flag dead_reckoning_invalid

Test coverage

• Tested with fixed wing simulation with AMC 1.37.19
  At start up before gps is fixed, but vehicle is in landed, dead_reckoning_invalid is not updated

After simulating gps loss and setting COM_DR_TOUT_T to 3 s dead_reckoning_invalid is true

After landing and switching navigation state to stabilized warning appear again as flag isnt updated when vehicle is on ground

[github-actions]

🔎 FLASH Analysis

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Updated: 2025-10-30T08:42:23