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Testing the effects of wind with SITL

Posted by Thomas Gehrmann on June 21, 2016 at 5:14am

Hello guys,

in the simulation there are the following parameters for testing the effects of wind:

SIM_WIND_DIR

SIM_WIND_SPD 

SIM_WIND_TURB

SIM_WIND_DELAY 

The first and second parameter (direction and speed) are clear, but was does SIM_WIND_DELAY do and which values can SIM_WIND_TURB take?

I also want to simulate wind shear, i.e. changing the wind speed with altitude. Does somebody know how to do that?

Thanks a lot!

Best regards,

Thomas 

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Replies

  • Thomas Gehrmann January 24, 2018 at 1:01am

    Thank you!


    Nicholas Engle said:

    Hi, I understand this is a year old topic, but after doing some research on my own I figured I would create an account and answer, as this thread shows up when googling "SIM_WIND_DELAY".

    The following conclusions were based on looking through the code of SITL.

    SIM_WIND_DELAY delays the sending of windspeed information, simulating part of an airspeed sensor. This is measured in milliseconds (ms). This is described in comments in the code.

    SIM_WIND_TURB randomly varies the horizontal and vertical wind speed. After recreating the code in MATLAB and testing, it seems that every time step the code adds vector to the wind at a random direction. In each direction (Horizontal and Vertical), the mean deviation from 0 is 0.16*SIM_WIND_TURB. For example, setting SIM_WIND_TURB to 10 would result in both horizontal (in a random yaw) and vertical deviations in the windspeed vector, with a mean deviation of 1.6 m/s.

    I hope this helps anyone digging up this thread, and feel free to ask questions if I was not clear enough. I wish this information was included in the SITL documentation... so people like me don't have to dig through c++ to learn aspects of the program.

  • Nicholas Engle January 23, 2018 at 12:34pm

    Hi, I understand this is a year old topic, but after doing some research on my own I figured I would create an account and answer, as this thread shows up when googling "SIM_WIND_DELAY".

    The following conclusions were based on looking through the code of SITL.

    SIM_WIND_DELAY delays the sending of windspeed information, simulating part of an airspeed sensor. This is measured in milliseconds (ms). This is described in comments in the code.

    SIM_WIND_TURB randomly varies the horizontal and vertical wind speed. After recreating the code in MATLAB and testing, it seems that every time step the code adds vector to the wind at a random direction. In each direction (Horizontal and Vertical), the mean deviation from 0 is 0.16*SIM_WIND_TURB. For example, setting SIM_WIND_TURB to 10 would result in both horizontal (in a random yaw) and vertical deviations in the windspeed vector, with a mean deviation of 1.6 m/s.

    I hope this helps anyone digging up this thread, and feel free to ask questions if I was not clear enough. I wish this information was included in the SITL documentation... so people like me don't have to dig through c++ to learn aspects of the program.

  • Yesica Villamil July 17, 2017 at 3:21pm

    Hello, 
    Did you find any information? You could share it please =)

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