# Drone is getting crashed in HITL ( MAVSDK example: offboard_position_ned2.py )

Source: https://forum.modalai.com/topic/1393/drone-is-getting-crashed-in-hitl-mavsdk-example-offboard_position_ned2-py
Category: Flight Core and Legacy VOXL (https://forum.modalai.com/category/9/flight-core-and-legacy-voxl)
Tags: voxl-cam
Posted: 2022-09-28 09:46:42 UTC by Anubhav
Replies: 2 · Views: 793

## Anubhav · 2022-09-28 09:46:42 UTC

Hi, 

I have been implementing MAVSDK example in HITL. Below I have linked their short videos. 
**My question is that why it's loosing it's local position in 2nd example and getting crashed and showing critical navigation failure message whilst odometry or qvio is working properly?** I have also attached mavlink messages and code execution below.
1. [Video ](https://drive.google.com/file/d/1K-P2dAsS8x2EU1jzKhX8jhk7KI9xt5Qf/view?usp=sharing)of hitl with MAVSDK example takeoff_and_land2.py
2. [Video ](https://drive.google.com/file/d/1ZZc6subJ8IrS2LLFk2EK8NzBabZy82tc/view?usp=sharing)of hitl with MAVSDK example offboard_position_ned2.py.

Mavlink messages and code execution of MAVSDK example takeoff_and_land2.py
```
root@apq8096:/home# python3 takeoff_and_land2.py udp://:14551
Waiting for mavsdk_server to be ready...
Connected to mavsdk_server!
Waiting for drone to connect...
Drone discovered with UUID: 5428614370902488403
Waiting for drone to have a global position estimate...
Global position estimate ok
-- Arming
[08:07:47|Debug] MAVLink: info: Armed by external command (system_impl.cpp:250)
-- Taking off
[08:07:47|Debug] MAVLink: critical: Failsafe enabled: No manual control stick input (system_impl.cpp:250)
[08:07:47|Debug] MAVLink: info: Failsafe mode activated (system_impl.cpp:250)
[08:07:47|Debug] MAVLink: info: [logger] /fs/microsd/log/2022-09-28/08_12_29.ulg (system_impl.cpp:250)
[08:07:47|Debug] MAVLink: info: Failsafe mode deactivated (system_impl.cpp:250)
[08:07:47|Debug] MAVLink: info: Using minimum takeoff altitude: 2.50 m (system_impl.cpp:250)
[08:07:48|Debug] MAVLink: info: Takeoff detected (system_impl.cpp:250)
-- Landing
[08:07:52|Debug] MAVLink: info: Landing at current position (system_impl.cpp:250)
```
Mavlink messages and code execution of MAVSDK example offboard_position_ned2.py.
```
python3 offboard_position_ned2.py udp://:14551
Using mavsdk server port 50051
Connecting to vehicle using port 14550
Waiting for mavsdk_server to be ready...
Connected to mavsdk_server!
-- Arming
[08:11:45|Debug] MAVLink: info: Armed by external command (system_impl.cpp:250)
-- Setting initial setpoint
-- Starting offboard
[08:11:45|Debug] MAVLink: critical: Failsafe enabled: No manual control stick input (system_impl.cpp:250)
-- Go 0m North, 0m East, -1m Down within local coordinate system
[08:11:45|Debug] MAVLink: info: Failsafe mode activated (system_impl.cpp:250)
[08:11:45|Debug] MAVLink: info: [logger] /fs/microsd/log/2022-09-28/08_16_54.ulg (system_impl.cpp:250)
[08:11:45|Debug] MAVLink: info: Failsafe mode deactivated (system_impl.cpp:250)
[08:11:47|Debug] MAVLink: info: Takeoff detected (system_impl.cpp:250)
-- Go 1m North, 0m East, -1m Down within local coordinate system, turn to face East
-- Go 1m North, 1m East, -1m Down within local coordinate system
[08:11:57|Debug] MAVLink: emergency: Critical navigation failure! Check sensor calibrat (system_impl.cpp:250)
[08:11:57|Warn ] Unknown StatusText severity (telemetry_impl.cpp:891)
[08:11:57|Debug] MAVLink: emergency: ion (system_impl.cpp:250)
[08:11:57|Warn ] Unknown StatusText severity (telemetry_impl.cpp:891)
-- Go 0m North, 1m East, -1m Down within local coordinate system, turn to face South
[08:12:01|Warn ] command temporarily rejected (21). (mavlink_commands.cpp:178)
[08:12:01|Debug] MAVLink: critical: Landing denied! Please land manually (system_impl.cpp:250)
Failed to land
-- Disarming
Disarming failed
root@apq8096:/home# [08:12:48|Debug] MAVLink: emergency: BARO #0 failed:  TIMEOUT! (system_impl.cpp:250)
[08:12:48|Warn ] Unknown StatusText severity (telemetry_impl.cpp:891)
```
Thanks!

## Reply by Zachary Lowell · 2022-09-28 16:09:06 UTC

@Anubhav are you still flying gazebo with the iris_vision instead of just the iris_hitl in the gazebo world?

## Reply by Anubhav · 2022-09-28 17:27:54 UTC

@Zachary-Lowell, Yes I am leveraging iris_vision in hitl_hiris.world file. Isn't it required to fly drone in VIO mode in simulation considering there is no GPS?