# Send Position to px4

Source: https://forum.modalai.com/topic/49/send-position-to-px4
Category: Flight Core and Legacy VOXL (https://forum.modalai.com/category/9/flight-core-and-legacy-voxl)
Tags: voxl-vision-px4, px4, voxl
Posted: 2020-12-01 14:27:32 UTC by rapit
Replies: 1 · Views: 1702

## rapit · 2020-12-01 14:27:32 UTC

Hi,
I was wondering how I have to configure px4 to get the position estimate from voxl for position mode.

The connection to `TELEM2`port of my Pixhawk4 works, I am getting Odometry Messages when `voxl-vision-px4` is running. I set the px4 parameter `EKF_AID_MASK` to `8` which is `vision position fusion`. I completely removed GPS from my drone. 

When I inspect `LOCAL_POSITION_NED` messages I see the `x,y` coordinates from the odometry but the `z` coordinate is very off. 

Any thoughts on that? Thank you!

## Reply by rapit · 2020-12-01 14:40:25 UTC

Nevermind, apparently I looked in the wrong places: 

[https://dev.px4.io/master/en/ros/external_position_estimation.html](https://dev.px4.io/master/en/ros/external_position_estimation.html) has the answer: `EKF2_HGT_MODE` must be set to `vision` to use the voxl odometry instead of the barometer. Closing this.