The design and development of the decca flight log

The paper first outlines some of the problems involved in the presentation of navigational data. The choice of co-ordinates is discussed and examples are given which seem to merit human judgment in preference to fully automatic computation. Convenient compromises requiring less complex computers are described, with details of the Decca Mark 01 Flight Log. The servo mechanisms involve a d.c. sign-changing circuit, a d.c. amplifier with a slope of 10 amperes per volt and backlash neutralizers. Mechanical and electronic frequency changers are compared.