No GPS fix and gyro not calibrating

ArduPlane Plane 4.5
1

Hey folks,
I’m trying to get set up on a scratch-built foam plane using Mission Planner with a Pixhawk kit I purchased nearly 10 years ago.
I’m having two problems as I try to get it ready to arm:
GPS won’t fix, and gyro not calibrated.
I’ve gone through the setup menus for accel and compass. I had to turn off the compass on the GPS because no matter what I seemed to do, it would say it was backwards.

Here’s the message log from the latest boot, in case it’s helpful. Any tips on resolving gyro and GPS issues? Let me know what other info I should share. Thanks in advance!

11/13/2024 2:46:44 PM : PreArm: GPS 1: Bad fix
11/13/2024 2:46:44 PM : PreArm: Gyros not calibrated
11/13/2024 2:46:44 PM : PreArm: Hardware safety switch
11/13/2024 2:46:13 PM : PreArm: GPS 1: Bad fix
11/13/2024 2:46:13 PM : PreArm: Gyros not calibrated
11/13/2024 2:46:13 PM : PreArm: Hardware safety switch
11/13/2024 2:45:42 PM : PreArm: GPS 1: Bad fix
11/13/2024 2:45:42 PM : PreArm: Gyros not calibrated
11/13/2024 2:45:42 PM : PreArm: Hardware safety switch
11/13/2024 2:45:31 PM : u-blox 1 HW: 00040007 SW: 7.03 (45969)
11/13/2024 2:45:17 PM : GPS 1: detected as u-blox at 230400 baud
11/13/2024 2:45:11 PM : PreArm: AHRS: waiting for home
11/13/2024 2:45:11 PM : PreArm: Gyros not calibrated
11/13/2024 2:45:11 PM : PreArm: Hardware safety switch
11/13/2024 2:45:10 PM : Throttle failsafe off
11/13/2024 2:45:10 PM : RCOut: PWM:1-14
11/13/2024 2:45:10 PM : AHRS: DCM active
11/13/2024 2:45:10 PM : ArduPilot Ready
11/13/2024 2:45:10 PM : Airspeed 1 not initalized, cannot cal
11/13/2024 2:45:10 PM : Airspeed 1 init failed
11/13/2024 2:45:10 PM : MS4525[0]: no sensor found
11/13/2024 2:45:10 PM : Barometer 1 calibration complete
11/13/2024 2:45:08 PM : Initialising ArduPilot
11/13/2024 2:45:08 PM : Calibrating barometer
11/13/2024 2:45:03 PM : Initialising ArduPilot
11/13/2024 2:44:58 PM : Initialising ArduPilot
11/13/2024 2:44:53 PM : Initialising ArduPilot
11/13/2024 2:44:48 PM : Initialising ArduPilot
11/13/2024 2:44:43 PM : Initialising ArduPilot
11/13/2024 2:44:43 PM : IMU0: fast sampling enabled 8.0kHz/1.0kHz
11/13/2024 2:44:43 PM : RCOut: Initialising
11/13/2024 2:44:43 PM : IOMCU: 0 0 411FC231
11/13/2024 2:44:43 PM : fmuv2 0025003D 3034510B 36353832
11/13/2024 2:44:43 PM : ChibiOS: 6a85082c
11/13/2024 2:44:43 PM : ArduPlane V4.5.7 (0358a9c2)
11/13/2024 2:44:42 PM : IMU0: fast sampling enabled 8.0kHz/1.0kHz
11/13/2024 2:44:42 PM : RCOut: Initialising
11/13/2024 2:44:42 PM : IOMCU: 0 0 411FC231
11/13/2024 2:44:42 PM : fmuv2 0025003D 3034510B 36353832
11/13/2024 2:44:42 PM : ChibiOS: 6a85082c
11/13/2024 2:44:42 PM : ArduPlane V4.5.7 (0358a9c2)
11/13/2024 2:44:42 PM : IMU0: fast sampling enabled 8.0kHz/1.0kHz
11/13/2024 2:44:42 PM : RCOut: Initialising
11/13/2024 2:44:42 PM : IOMCU: 0 0 411FC231
11/13/2024 2:44:42 PM : fmuv2 0025003D 3034510B 36353832
11/13/2024 2:44:42 PM : ChibiOS: 6a85082c
11/13/2024 2:44:42 PM : ArduPlane V4.5.7 (0358a9c2)

2

Looks like the GPS is working, but it just hasn’t got a lock. It needs a good clear view of the sky, and if it’s been on the shelf for 10 years it’s going to be a very basic sensor that is going to need a long time to get a good lock. You might need to wait 10 minutes outside or more for that first lock.

3

Awesome, thanks for the tip! I will give this a shot as soon as the rain lets up!

You think there’s a chance the “gyros not calibrated” error will go away too once GPS gets a fix? I’m stumped on what else I can do for the gyros. All I see on the Accel Calibration tab are the 3 green buttons. On the first green button I orient the plane all six ways as it directs, holding it still and as precisely as it can, and it says it calibrates successfully. On the other two I just leave it flat on the ground and they both also say they calibrate successfully, though sometimes they had said unable or fail, but last time I did it all 3 were success. Anything else I’m supposed to do for gyro calibration?

4

I don’t expect that the gyro error goes away with a good gps fix as these two sensors are completely different and unrelated to each other.
For gps error @Allister gives the first approach. The time to first fix with wrong gps almanach data could be even longer as 10 minutes.
Regarding the gyro error read again carefully this:
https://ardupilot.org/plane/docs/common-accelerometer-calibration.html
Using all three methods is wrong. Either use the first or the third methode. The first methode is the best if it is praticall for you. Additional you can use after the first methode the second methode but only if rally required. So I would recommend to use the first method only and check if the error is gone.

1 Like
5

Hey thank you for your reply.
I still haven’t gotten GPS fix, though I’ve left it on outdoors and/or by a window for multiple extended periods of time.
For the gyro error - I re-calibrated using the first method only. While the “Gyros not calibrated” method disappeared, I now get this message: “PreArm: AHRS: EKF3 Yaw inconsistent 63 deg. Wait o”
I was getting this error before, and tried to solve it be deselecting the GPS’s compass from the “Compass” tab under the Mandatory Hardware Setup menu. I’m not sure why I’m still getting it if I’m only using one compass. Any tips? Thanks in advance.

6

Update:
Achieved GPS lock!!! Wow. It took about an hour, but I slowly watched it bounce around, first in Australia, then in mid North America, then off the Pacific coast, and now finally it’s got lock!
Now the only error I’m getting is that it’s again saying “Gyros inconsistent”. I will try calibrating gyro again now with GPS lock.