Method and system for providing integrity for hybrid attitude and true heading

One embodiment is directed towards a method for providing integrity for a hybrid navigation system using a Kalman filter. The method includes determining a main navigation solution for one or more of roll, pitch, platform heading, or true heading for the vehicle using signals from a plurality of GNSS satellites and inertial measurements. Solution separation is used to determine a plurality of sub-solutions for the main navigation solution. The method also includes determining a separation between the main navigation solution and each of the sub-solutions, and a discriminator for each of the separations. If a discriminator is greater than the threshold the GNSS satellite at fault can be excluded. The method also includes determining a separation variance between the main navigation solution and each of the sub-solutions, a threshold for detection of a satellite failure based on the separation variances; and a protection limit that bounds error in the main navigation solution based on the threshold.