Modeling INS Errors by Linear State Equations

The accuracy of an INS is affected by various sources. These include errors during the initial alignment procedure, sensor errors, and the limitations of the processing algorithm. To see the effect of these errors on the navigational output parameters (position, velocity and attitude) it is vital to understand their propagation through the navigation equations. Once the nature of the errors is known, one can mitigate them by proper modeling and estimation techniques. This usually requires external aiding sources in order to limit the errors and predict their behavior. Hence error models are required for the analysis and estimation of the error sources associated with any inertial navigation system.