# M500 driff when flying VIO indoor navigation.

Source: https://forum.modalai.com/topic/95/m500-driff-when-flying-vio-indoor-navigation
Category: Development Drones (https://forum.modalai.com/category/44/development-drones)
Tags: m500
Posted: 2021-01-14 10:02:30 UTC by Vũ Văn Long
Replies: 6 · Views: 1882

## Vũ Văn Long · 2021-01-14 10:02:30 UTC

Hello, as the topic name when I starting to fly indoor nav with M500 VOXL frame, the UAV not go up straight but driff to the left side or right side (randomly). I also checking the Local_position_NED is 0,0,0 before the flight.
Here is the "systemctl status voxl-vision-px4"
![2.png](https://forum.modalai.com/assets/uploads/files/1610618418614-2.png) 
and when i test the odometry with "voxl-test-vision-lib -o"
![3.png](https://forum.modalai.com/assets/uploads/files/1610618520707-3.png) 
pls give me some advice.

## Reply by modaltb (ModalAI staff) · 2021-01-15 22:58:25 UTC

Hi @Vũ-Văn-Long ,

In order to better understand the setup, are you flying in offboard mode or manually through RC in position mode?

Thanks!

## Reply by Vũ Văn Long · 2021-01-16 07:04:44 UTC (in reply to modaltb)

@modaltb hi, i'm just trying to take-off manually though RC in position mode.

## Reply by Vũ Văn Long · 2021-01-16 07:28:46 UTC

every step is correct with the manual document. Here is what we do with the UAV. In the last week i had tested the UAV load in position mode and it's work well, after that i also tried with MavROS node to take-off UAV in Offboard mode. we would set the altitude to take off is 0.5 m but the UAV takeoff higher than 1m much (i had build rosnode after launch). 
**But** it was other problem, in this week we had installed a asus xtion camera and a raspberry pi at the bottom of m500 frame, then trying to maunally filght at position mode but the driff has occurred.

## Reply by Vũ Văn Long · 2021-01-18 03:29:40 UTC

Here is the video of flight with position mode, what is the problem ??? 
[video link](https://drive.google.com/file/d/1qp6mNSRsZGpFAOMvYYFDgjBBIwP7-TGx/view?usp=sharing)

## Reply by Chad Sweet (ModalAI staff) · 2021-01-18 04:21:19 UTC

thanks for sending the video. We'll look at this in detail. Can you please dump /etc/modalai/voxl-vision-px4.conf and provide? Can you make sure offboard_mode: "off"?

## Reply by Vũ Văn Long · 2021-01-18 08:39:57 UTC

@Chad-Sweet oh my godness. My mistaken, i didn't realise that before that i had configured UAV off board mode. when I check the /etc/modalai/voxl-vision-px4.conf the offboard_mode ="figure_eight" => so that's why it's cause the problem here. anyway, it's work again, thank you so much for the effective support