# Arm the RB5 drone with Mavros only

Source: https://forum.modalai.com/topic/4175/arm-the-rb5-drone-with-mavros-only
Category: General Questions (https://forum.modalai.com/category/2/general-questions)
Posted: 2025-02-13 20:48:46 UTC by selina
Replies: 4 · Views: 790

## selina · 2025-02-13 20:48:46 UTC

Dear SIr or Madam,

I wish to use the mocap data instead of the GPS for telling the drone's position to use it indoor.

I wish to arm the drone with mavros or QGC settings. I have tried setting parameter COM_RC_IN_MODE and COM_ARM_WO_GPS to 4 and 1. Also I want to use the mode OFFBOARD. The QGC fails so I turned to Mavros instead.

I calibrate the senson in QGC beforehand and now I wish to arm the drone via:

ros2 service call /mavros/cmd/arming mavros_msgs/srv/CommandBool "{value: true}"

The status of the drone is always "STANDBY" but not "ACTIVE".

Could the drone be armed with Mavros only? Or is there anything I ignored? 

Best wishes,
Selina

## Reply by Eric Katzfey (ModalAI staff) · 2025-02-14 00:05:40 UTC

@selina QGC fails to arm in offboard mode or fails to go into offboard mode at all? What version of VOXL SDK are you using?

## Reply by selina · 2025-02-16 19:50:08 UTC (in reply to Eric Katzfey)

@Eric-Katzfey 

QGC could go into offboard mode. I can also make the drone into offboard mode via mavros. But the problem is that it still cannot arm and then takeoff through mavros control (udp connection). 

I am using qualcomm flight rb5 drone with default settings. Do I need to consider the specific version of VOXL SDK in my drone?

I have changes the COM_ARM_WO_GPS to 1 for not using GPS.

QGC complains about Not Ready still.

## Reply by Eric Katzfey (ModalAI staff) · 2025-02-16 23:20:31 UTC (in reply to selina)

@selina Can you get a PX4 log? You would need to, from the command line, issue `px4-logger on`, wait a couple of seconds, try to arm, then issue `px4-logger off`. You should now see a new log in `/data/px4/log` somewhere.

## Reply by selina · 2025-02-18 18:28:23 UTC (in reply to Eric Katzfey)

@Eric-Katzfey 

Thanks for answering! I have managed to solved this problem by using proper MOCAP data instead of GPS.

I did not test in the QGC. But for mavros I succesfully armed the drone, which is what I really want for doing more control.

I wonder if there is any tutorial or documentation for doing low-level control, such as to do control specifically on motors, PWM, instead of using PX4 to do high-level control.

Thanks for your help again!