# Position Mode Rejected

Source: https://forum.modalai.com/topic/1141/position-mode-rejected
Category: General Questions (https://forum.modalai.com/category/2/general-questions)
Tags: position-mode, uart, px4, ekf2
Posted: 2022-07-21 20:51:17 UTC by rapit
Replies: 1 · Views: 1753

## rapit · 2022-07-21 20:51:17 UTC

Hi,
I tried the voxl-cam for the first time and all seems to be working fine except that px4 is not getting into position mode.

`voxl-inspect-qvio` prints reasonable poses, I can see the Odometry topic in QGC with 30 hz with x,y values not zero.

My `EKF2_AID_MASK` is `280` and with the same parameters and the voxl flight-deck I managed to start in position mode without GPS attached. 

Problem seems to be that I cannot get values in `LOCAL_POSITION_NED` and nothing is being output on `uorb top vehicle_visual_odometry` in a nuttx console.

I made a cable to connect the pixhawk4 and the voxlcam, which is twice as long as in the old setup. The `voxl-vision-px4` systemd service suggests that UART is connected, but maybe there could be some issue in sending the data?

Do you have any suggestions?

Thanks!

## Reply by James Strawson (ModalAI staff) · 2022-07-25 18:44:39 UTC

Which version of PX4 are you running on the Pixhawk and do you have a magnetometer connected? EKF2 is generally unhappy about about starting without a magnetometer in PX4 1.11 so we patched the PX4 firmware for Flight Core to get around this. In PX4 1.12 and newer the following PX4 parameter can be set to allow EKF2 to allow position mode without a GPS/Mag

```
## disable mag
SYS_HAS_MAG	0	
EKF2_MAG_TYPE	5	
```