Optimizing the gains of baro-inertial vertical channel mechanizations

Abstract

This work revisits the problem of Inertial Navigation Systems (INSs) vertical channel stabilization via barometer-aided feedback control loops (also referred to as mechanizations). The origin of the problem is associated with the gravity compensation positive feedback carried out internally to the INS, which acts destabilizing its altitude and vertical velocity solutions. In the vast majority of works dealing with the problem, there is an excess of empiricism regarding the mechanization tuning procedure, as well as an incipience w.r.t. the use of optimization techniques. This work, hence, investigates the use of performance indices, directly applied to the unit step response of the integrated altitude, aiming at optimizing the gains of the baro-inertial vertical channel mechanization. Four performance indices are particularly analyzed, namely: the Integral Absolute Error (IAE), Integral Squared Error (ISE), Integral of Time Multiplied Absolute Error (ITAE) and Integral of Time Multiplied Squared Error (ITSE). As main contribution of the paper, we demonstrate that the mechanization tuning based on ITAE minimization is able to over-perform the remaining tested indices, as well as other traditional empirical and optimized tunings proposed in the literature, in terms of altitude and vertical velocity Root Mean Squared Errors (RMSE). Experimental tests are carried out whose results confirm the adequacy of the verifications.