Wander Azimuth Mechanizations
In addition to the north-slaved mechanization, the GPSoft Inerial Navigation toolbox supports wander azimuth mechanizations including Free Azimuth, Foucault and Unipolar. Consider the following example simulations produced with the toolbox. In each case, a great circle path from New York to Istanbul was followed ( See Great Circle Path INS Simulation with Sensor Errors)
Free Azimuth Simulation
In the free azimuth case, the vertical component of craft rate is set to zero. As a result, the computed azimuth (yaw) remains constant. The actual heading is given by yaw-minus-wander-angle. Note that the wind is assumed to be zero thus the heading is also the aircraft course.
Since the local-level frame is NOT east-north-up (ENU), additional computation is required to determine east and north velocities: