How tachymetric anti-aircraft fire control predicted a target

What does tachymetric anti-aircraft fire control do?

It derives target movement from successive observations and calculates the gun bearing and elevation needed to lead the aircraft.

A tachymetric fire-control system takes measured range, height, and bearing from radar reports or visual observations. Successive observations allow its computer to derive the target's speed, direction, and rate of range change. It then calculates the gun elevation and bearing needed to meet the target's predicted movement. The examples named here are analog systems: the fuze-keeping clock, High Angle Control System, and US Mark 37.