• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.39 no.4
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• pp.332-340
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• 2011

A missile with a strapdown seeker should properly estimate line-of-sight(LOS) rate using its attitude information and the look angle of the seeker because LOS rate information in an inertial coordinate system, which is used for a proportional navigation(PN) homing guidance, can not be obtained directly. However, an unnecessary feedback loop(Parasite Loop) is formed in the guidance and control loop, and it may cause the guidance performance degradation or even the unstability of the system(Parasite Effect). This paper presents estimation methods for the LOS rate information and effective ways to minimize the parasite effect using Routh-Hurwitz stability criterion. Various numerical simulations are also included to verify the proposed methods.