The external AHRS has no GPS fix or has not finished aligning
What ArduPilot says:
- SensAItion Aligning
- MicroStrain5 no GPS lock
- ExternalAHRS: No origin
- VectorNav no GPS1 lock
- VectorNav no GPS2 lock
The external AHRS (a separate navigation unit that supplies attitude and position) is talking to ArduPilot but cannot give a position yet. “no GPS lock”: its GPS receiver has less than a 3D fix; GPS2 is the second antenna of a two-antenna unit. “No origin”: it has not yet reported the first position from which all others are measured. “Aligning”: its own estimator is still finding level and heading. The aircraft will not arm.
What to do, most likely first
The unit's GPS has no fix yet: indoors, or just powered on.
FixWait outside under open sky.
A GPS antenna of the unit is unplugged or shaded by the airframe.
CheckIt is always the same antenna, GPS1 or GPS2, that has no lock.
FixCheck the antenna cable and give the antenna a clear view of the sky.
Parameters to look at
| Parameter | What it is |
|---|---|
EAHRS_TYPE | AHRS type |
EAHRS_SENSORS | External AHRS sensors |
The code that sends it
SensAItion Aligning
libraries/AP_ExternalAHRS/AP_ExternalAHRS_SensAItion.cpp AP_ExternalAHRS_SensAItion::pre_arm_check() · Open in ArduPilot Copter-4.7.1
MicroStrain5 no GPS lock
libraries/AP_ExternalAHRS/AP_ExternalAHRS_MicroStrain5.cpp AP_ExternalAHRS_MicroStrain5::pre_arm_check() · Open in ArduPilot Copter-4.7.1
ExternalAHRS: No origin
libraries/AP_ExternalAHRS/AP_ExternalAHRS.cpp AP_ExternalAHRS::pre_arm_check() · Open in ArduPilot Copter-4.7.1
VectorNav no GPS1 lock
libraries/AP_ExternalAHRS/AP_ExternalAHRS_VectorNav.cpp AP_ExternalAHRS_VectorNav::pre_arm_check() · Open in ArduPilot Copter-4.7.1
And 1 more messages, sent from the same places.