Digital Differential Analyzers vs General Purpose Digital Computers for Schuler-Tuned Inertial Navigation Systems

A pure Schuler-tuned terrestrial inertial navigator with polar mode capability is considered. The general computing requirements for digital mechanizations are outlined and pertinent characteristics for digital differential analyzers (DDA) and general purpose (GP) digital computers are listed. Factors involved in choosing between the two, and combinations thereof, are discussed, It is concluded that the addition of a DDA section for complete or partial performance of the inertial navigation function provides no advantage for the faster GP digital computers available for airborne inertial navigation, but might well be advantageous for a very slow GP digital computer.