# How to simulate magnetometer used on navigation system?

Magnetometer is used to measure yaw angle which will be used on AHRS system.When I simulate the magnetometer in matlab, I feel confused about what unit should be used for measurements magnetometer?Should I use μT(microtesla),rad or degree?

I know in real world, the magnetometer is to measure earth magnetic field, so it should be μT. the reason that I feel confused is that:In some papers, their simulation says $$B_{i}$$(earth's magnetic field) is given by $$[\frac{1}{\sqrt{2}},0,\frac{1}{\sqrt{2}}]$$ or $$[1;0;1]$$,symmetry-preserving observer.page11 and they didn't give the unit of above vector. I also find a book, called Small Unmanned Aircraft: Theory and Practice, it introduced how to simulate IMU sensors and says the standard deviation and bias error of Magnetometer could be 0.3 degrees and 1 degree.

So I am totally confused about the unit and value of the earth's magnetic field or Magnetometer measurements.

• It is impossible to answer this question without knowing what you want to achieve with your simulation. Are you analysing the electronics, are you developing navigation software, are you investigating the effect of magnetic anomalies on navigation performance, are you modeling the dynamic response of a magneto meter to a changing magnetic field, something else? Feb 5 at 9:09
• I am designing a estimator for the navigation system. so the measurements to my estimator are positions(GPS),acceleration(accelerometer),magnetic field(magnetometer).Right now I want to add some noise and bias to the measurements and see the estimation performance of the estimator. so in my case, I want to figure out the unit and value range of the magnetometer so that I can add the right noises. Feb 5 at 15:51

• For my case, the magnetometer would be a MEMS electric magnetometer. If a paper says $B_{i}$(earth's magnetic field) is given by $[\frac{1}{\sqrt{2}},0,\frac{1}{\sqrt{2}}]$ or $[1;0;1]$. Since they didn't give the unit, do you know the unit according to the values they give? is it μT, rad or degree? Feb 5 at 15:46