Guided No GPS - local position pose companion computer

ArduCopter Copter 4.4
1

Hi all,

Our team has made ArduCopter 4.4.4 work with offboard control (ATTITUDE_TARGET) with our companion controller in GUIDED mode.
We want to make it work without GPS in guided, no GPS mode. And the problems started going from there.

Hardware is the same as we had on the GPS drone, but we replaced GPS sensor for a compass
FC: Kakute H7 v1.3
Compass: CUAV IST8 External Compass

Arducopter params:

AHRS_EKF_TYPE     = 3 # Use EK3 for estimation
EK2_ENABLE        = 0 # Disable EK2
EK3_ENABLE        = 1 # Enable EK3
EK3_SRC1_YAW      = 1 # Compass
GPS_TYPE          = 0 # disable the GPS
ARMING_CHECK      = ? # disable GPS checks
EK3_SRC1_POSXY    = 0 # None
EK3_SRC1_POSZ     = 1 # Baro
EK3_SRC1_VELXY    = 0 # None
EK3_SRC1_VELZ     = 0 # None

So, when I launch the drone, I set the EKF home position in the mission planner, arm it, and there is no local position message appears: LOCAL_POSITION_NED
But the velocity is appearing on GLOBAL_POSITION_INT
We need only the velocities to run our control, but I can’t figure out how to properly get it.

Any help is appreciated.

2

Hello @demwing welcome to the community,

You have to explicitly request for the mavlink messages that you want.

3

Thx, but in this line for global pose there is a check only for velocity: https://github.com/ArduPilot/ardupilot/blob/3926e06508ffacbed79ada958b3dd25114cab968/libraries/GCS_MAVLink/GCS_Common.cpp#L5612
And in the local pose it needs vel & pose: https://github.com/ArduPilot/ardupilot/blob/3926e06508ffacbed79ada958b3dd25114cab968/libraries/GCS_MAVLink/GCS_Common.cpp#L2777
Maybe we understood the offboard mode different?
We have adapted our code to work with global pose velocity message, so we can fly, but would be great to understand it

4

I still do not understand your problem. Can you please explain it in more detail?

5

Are you referring to this?

6

We did request the message via Mavlink, but there is no Local Poistiion Pose message incoming.
We noticed that GPS global position is coming, and we got our velocities from there.
But my question is how to repeat the setup that we have in GUIDED mode to GUIDED NO GPS mode - meaning getting LOCAL_POSITION_NED message not the GLOBAL_POSITION_INT

7

Yes, we already succeeded doing some control in this mode, but just needed additional tweaks to get the velocities.
We would like to have the same setup of our code for GUIDED and GUIDED NO GPS, but it doesn’t seem to be possible rn

8

Will this be helpful to you?

LOCAL_POSITION_NED

9

We set these params, but do not receive LOCAL POSIITION NED, only the GLOBAL POSITION INT

10

Seem like someone else get into this issue too.

Indoor? Is it because there is no indoor navigation system such as Aruco map for the drone to navigate?

11

Hi,
No outdoor, we set the EKF origin and Home by hand and then fly by hand and take over via our controller from the companion computer ATTITUDE TARGET.
Thanks,
Yurii