Advanced Avionics Practice Test

Attitude accuracy is the foundation of an inertial navigation system. Gyros measure how the platform is rotating, and those rates are integrated to keep track of orientation. If a leveling gyro drifts, it introduces a slow, unwarranted bias in the estimated attitude—the system starts to think the platform is slightly tilted even when it isn’t.

That attitude error matters because all accelerations must be expressed in the navigation frame. The wrong orientation means accelerations (including gravity) are projected into the wrong directions, so the calculated velocity and then the position drift over time. The gravity reference used to determine level is also misread, compounding the misalignment. So, leveling gyro drift directly degrades the INS outputs by corrupting the attitude estimate, which then leads to erroneous navigation results.