Instrument Approach System Steering Computer

This paper is concerned with the theory of an air-borne electronic steering computer and associated instrumentation used in aircraft guidance during an instrument approach. It is shown that this guidance problem may be analyzed with advantage as one of feedback control. Means are discussed for achieving a stable flight path in the resultant variable gain feedback control system. Principles of complementary linear filtering are presented and combination of certain control signals in a complementary filter is shown to result in an improved system. The importance of the form of cockpit instrumentation in this guidance problem is indicated.