# Multi vehicle simulation - Queries

**URL:** <https://discuss.px4.io/t/multi-vehicle-simulation-queries/8255>\
**Category:** Uncategorized\
**Created:** [October 25, 2018, 1:44pm UTC](https://discuss.px4.io/t/multi-vehicle-simulation-queries/8255 "2018-10-25T13:44:19Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![Vrinda](https://discuss.px4.io/letter_avatar_proxy/v4/letter/v/839c29/32.png) [@Vrinda](https://discuss.px4.io/u/Vrinda)\
**Post date:** [October 25, 2018, 1:44pm UTC](https://discuss.px4.io/t/multi-vehicle-simulation-queries/8255/1 "2018-10-25T13:44:19Z")

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Hello !  
I followed the instructions mentioned in the dev guide. However I am unable to get the output. This is what I get when I do,  
roslaunch px4 multi\_uav\_mavros\_sitl.launch

 ![](https://discuss.px4.io/uploads/default/original/2X/6/6d97f51cc51d71978c1e232680e7b07d775b810e.png)

I needed some help.  
Thank you for your time !

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**Author:** ![shrit](https://discuss.px4.io/letter_avatar_proxy/v4/letter/s/ea5d25/32.png) [@shrit](https://discuss.px4.io/u/shrit)\
**Post date:** [October 25, 2018, 2:58pm UTC](https://discuss.px4.io/t/multi-vehicle-simulation-queries/8255/2 "2018-10-25T14:58:34Z")

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There are some problems with multi vehicles simulations,

I have more or less the same issue, I think it is a python problem (migration from 2.7 to 3.7)

I will give an answer once I find a solution

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<div class="post-metadata">

**Author:** ![Vrinda](https://discuss.px4.io/letter_avatar_proxy/v4/letter/v/839c29/32.png) [@Vrinda](https://discuss.px4.io/u/Vrinda)\
**Post date:** [October 25, 2018, 3:03pm UTC](https://discuss.px4.io/t/multi-vehicle-simulation-queries/8255/3 "2018-10-25T15:03:37Z")

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Should I install python 2.7 then ? Thanks much @shrit. Will wait for your reply.

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**Author:** ![shrit](https://discuss.px4.io/letter_avatar_proxy/v4/letter/s/ea5d25/32.png) [@shrit](https://discuss.px4.io/u/shrit)\
**Post date:** [October 25, 2018, 3:05pm UTC](https://discuss.px4.io/t/multi-vehicle-simulation-queries/8255/4 "2018-10-25T15:05:22Z")

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You need to install gazebo\_ros package  
you are using kinetics, you have already python 2.7 installed on your machine

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<div class="post-metadata">

**Author:** ![Vrinda](https://discuss.px4.io/letter_avatar_proxy/v4/letter/v/839c29/32.png) [@Vrinda](https://discuss.px4.io/u/Vrinda)\
**Post date:** [October 25, 2018, 3:10pm UTC](https://discuss.px4.io/t/multi-vehicle-simulation-queries/8255/5 "2018-10-25T15:10:13Z")

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Apologies ! Yes I have 2.7 python. I will try gazebo\_ros and keep you posted.

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**Author:** ![Vrinda](https://discuss.px4.io/letter_avatar_proxy/v4/letter/v/839c29/32.png) [@Vrinda](https://discuss.px4.io/u/Vrinda)\
**Post date:** [October 26, 2018, 12:01pm UTC](https://discuss.px4.io/t/multi-vehicle-simulation-queries/8255/7 "2018-10-26T12:01:29Z")

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Hey I installed gazebo\_ros. The multi vehicle simulation tutorial works now. Thanks much for your help @shrit !