Add Pointing error over a reference attitude message

[luca1396]

Hi!
I would like to ask if there is a way to add a random error on the spacecraft attitude.
I'm trying to simulate a scenario in which I have a Nadir pointing satellite that is imaging a set of ground points.
I'm imposing the Hill frame using the reference attitude message of the HillPoint module and the GroundMapping module to evaluate the instants in which my Nadir pointing camera can acquire the ground points. So my idea was to add to the reference attitude message a gaussian error with a 3-sigma equal to the expected pointing accuracy of my platform but I can't figure out how I could do it.
A couple of ideas came to my mind but I'm not sure if they are feasible:

• I was wondering if the attRefCorrection module could be useful in this sense (maybe there is a way to define a time varying sigma_RN?).
• Since the groundMapping module takes the SCStatesMsgPayload message I was also thinking if there is a way to perturb the attitude contained in this message. An idea that came to my mind was to use an ad-hoc simpleNav module to perturb the attitude message. But I don't know if there is a way to create a SCStatesMsgPayload message from the outputs of the SimpleNav module.

Is there a way in which I could do it or do I need to implement the actual actuators and guidance system to add a realistic pointing error to my simulation?