# Having urgent problem while launching PX4 SITL

**URL:** <https://discuss.px4.io/t/having-urgent-problem-while-launching-px4-sitl/40723>\
**Category:** PX4 Autopilot\
**Created:** [September 14, 2024, 4:05pm UTC](https://discuss.px4.io/t/having-urgent-problem-while-launching-px4-sitl/40723 "2024-09-14T16:05:58Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![SvrT](https://discuss.px4.io/letter_avatar_proxy/v4/letter/s/35a633/32.png) [@SvrT](https://discuss.px4.io/u/SvrT)\
**Post date:** [September 14, 2024, 4:05pm UTC](https://discuss.px4.io/t/having-urgent-problem-while-launching-px4-sitl/40723/1 "2024-09-14T16:05:58Z")

</div>

I installed PX4 SITL by following this - [Notion – The all-in-one workspace for your notes, tasks, wikis, and databases.](https://kuat-telegenov.notion.site/How-to-setup-PX4-SITL-with-ROS2-and-XRCE-DDS-Gazebo-simulation-on-Ubuntu-22-e963004b701a4fb2a133245d96c4a247)

Once I try to launch everything, I get these errors -  
svrt@svrt-popos:~$ cd PX4-Autopilot/ && make px4\_sitl gz\_x500  
[0/1] cd /home/svrt/PX4-Autopilot/buil…topilot/build/px4\_sitl\_default/bin/px4

* * *

| \_\_\_ \ \ \ / / / |  
| |_/ / \ V / / /| |  
| \_\_/ / \ / /_| |  
| | / /^\ \ \_\_\_ |  
\_| / / |\_/

px4 starting.

INFO [px4] startup script: /bin/sh etc/init.d-posix/rcS 0  
INFO [init] found model autostart file as SYS\_AUTOSTART=4001  
INFO [param] selected parameter default file parameters.bson  
INFO [param] importing from ‘parameters.bson’  
INFO [parameters] BSON document size 251 bytes, decoded 251 bytes (INT32:11, FLOAT:2)  
INFO [param] selected parameter backup file parameters\_backup.bson  
INFO [dataman] data manager file ‘./dataman’ size is 7872608 bytes  
INFO [init] Gazebo simulator  
INFO [init] starting gazebo with world: /home/svrt/PX4-Autopilot/Tools/simulation/gz/worlds/default.sdf  
WARN [init] PX4\_GZ\_MODEL\_POSE not set, spawning at origin.  
INFO [gz\_bridge] world: default, model name: x500\_0, simulation model: x500  
INFO [gz\_bridge] Requested Model Position: 0,0,0,0,0,0  
INFO [gz\_bridge] Model position z is less or equal 0.0, moving upwards  
ERROR [gz\_bridge] Service call timed out. Check GZ\_SIM\_RESOURCE\_PATH is set correctly.  
WARN [gz\_bridge] Service call timed out as Gazebo has not been detected.  
libEGL warning: egl: failed to create dri2 screen  
libEGL warning: egl: failed to create dri2 screen  
libEGL warning: egl: failed to create dri2 screen  
INFO [lockstep\_scheduler] setting initial absolute time to 1256000 us  
INFO [commander] LED: open /dev/led0 failed (22)  
INFO [tone\_alarm] home set  
INFO [uxrce\_dds\_client] init UDP agent IP:127.0.0.1, port:8888  
INFO [mavlink] mode: Normal, data rate: 4000000 B/s on udp port 18570 remote port 14550  
INFO [mavlink] mode: Onboard, data rate: 4000000 B/s on udp port 14580 remote port 14540  
INFO [mavlink] mode: Onboard, data rate: 4000 B/s on udp port 14280 remote port 14030  
INFO [mavlink] mode: Gimbal, data rate: 400000 B/s on udp port 13030 remote port 13280  
INFO [logger] logger started (mode=all)  
INFO [logger] Start file log (type: full)  
INFO [logger] [logger] ./log/2024-09-14/16\_01\_37.ulg   
INFO [logger] Opened full log file: ./log/2024-09-14/16\_01\_37.ulg  
INFO [mavlink] MAVLink only on localhost (set param MAV\_{i}_BROADCAST = 1 to enable network)  
INFO [mavlink] MAVLink only on localhost (set param MAV_{i}\_BROADCAST = 1 to enable network)  
INFO [px4] Startup script returned successfully  
pxh\> WARN [health\_and\_arming\_checks] Preflight Fail: No connection to the ground control station   
WARN [health\_and\_arming\_checks] Preflight Fail: No connection to the ground control station   
WARN [health\_and\_arming\_checks] Preflight Fail: No connection to the ground control station   
pxh\> commander takeoff  
pxh\> WARN [commander] Arming denied: Resolve system health failures first   
INFO [tone\_alarm] notify negative

The errors -  
ERROR [gz\_bridge] Service call timed out. Check GZ\_SIM\_RESOURCE\_PATH is set correctly.  
WARN [gz\_bridge] Service call timed out as Gazebo has not been detected.  
and -  
WARN [health\_and\_arming\_checks] Preflight Fail: No connection to the ground control station   
pxh\> commander takeoff  
pxh\> WARN [commander] Arming denied: Resolve system health failures first

My bashrc already has this - export GZ\_SIM\_RESOURCE\_PATH=/home/svrt/PX4-Autopilot/Tools/simulation/gz

I just don’t understand what I am doing wrong. Please help