Magnetometer Sensor Noise Std is scaled by a factor of 1.5

[AmolikaSoni]

Describe the bug The standard deviation provided as input for magnetometer modelling is scaled by a factor of 1.5

To reproduce Locate line no. 71 in https://github.com/AVSLab/basilisk/blob/develop/src/simulation/sensors/magnetometer/magnetometer.cpp auto nMatrix = (this->senNoiseStd * 1.5).asDiagonal();

Expected behavior Not sure on why 1.5 is being multiplied.

Screenshots Code lines already mentioned above

[schaubh]

Howdy @AmolikaSoni , thanks for the info. I'm not sure either why this 1.5 multiplier was added there in the original code. I'll take a look this weekend and correct or document if needed.

[AmolikaSoni]

Hi @schaubh, any updates on this? I just found the same scaling of 1.5 in the coarse sun sensor modeling as well! https://github.com/AVSLab/basilisk/blob/develop/src/simulation/sensors/coarseSunSensor/coarseSunSensor.cpp

[schaubh]

Howdy @AmolikaSoni , I found the same. I searched the BSK code base for the use of .setNoiseMatrix() and found that only the magnetometer and CSS modules use the 1.5 multiplier. At this point I have a task to make a branch to remove the 1.5x term and document this change in the known issues file.

[sdunlap-afit]

Hi @schaubh, While reviewing the following document, I came across multiple references to scaling standard deviations by 1.5 and remembered this thread. Is the document correct, or should I provide the desired standard deviations without scaling? Thank you for your time.

"where senRotNoiseStd and senTransNoiseStd are input by the user as 1.5x the desired standard deviation as scalar floats."

https://github.com/AVSLab/basilisk/blob/develop/src/simulation/sensors/imuSensor/_Documentation/BasiliskCorruptions.pdf

[schaubh]

@sjkcarnahan , you wrote this original documentation. Do you recall why this 1.5x factor was put in there? Some modules used it, most didn't?