Stability region analysis of the parasitic loop of the semi-strapdown homing seeker

Abstract

The stability of the parasitic loop induced by the disturbance rejection effect (DRE) of a semi-strapdown homing seeker (SSHS) is analysed in this paper. First, the seeker’s tracking controller is designed so as to have a simple structure and then the explicit relationships between the control parameters and the desired performance index is presented. Mathematical models of the DRE of the SSHS and the parasitic loop are then proposed. The approximate maximum magnitude of the seeker’s DRE as a function of the friction coefficient and the counter electromotive force coefficient is also given. Routh’s criterion is used to obtain the approximate stability region of the parasitic loop. The necessary and sufficient conditions which ensure the stability of the parasitic loop are directly related to the seeker’s control parameters. This approach provides direct theoretical support for the design of a seeker’s control system. Simulations are performed to verify the validity of the stability analysis performed on the parasitic loop.