Page "Artillery" Paragraph 67

All these calculations to produce a quadrant elevation ( or range ) and azimuth were done manually by highly trained soldiers using instruments, tabulated data, data of the moment and approximations until battlefield computers started appearing in the 1960s and 1970s.

While some early calculators copied the manual method ( typically substituting polynomials for tabulated data ), computers use a different approach.

They simulate a shell's trajectory by ' flying ' it in short steps and applying data about the conditions affecting the trajectory at each step.

This simulation is repeated until it produces a quadrant elevation and azimuth that lands the shell within the required ' closing ' distance of the target co-ordinates.

NATO has a standard ballistic model for computer calculations and has expanded the scope of this into the NATO Armaments Ballistic Kernel ( NABK ) within the SG2 Shareable ( Fire Control ) Software Suite ( S4 ).