Editing Fire-control system (section)

===Anti-aircraft based fire control===
By the start of [[World War II]], aircraft altitude performance had increased so much that [[anti-aircraft]] guns had similar predictive problems, and were increasingly equipped with fire-control computers. The main difference between these systems and the ones on ships was size and speed. The early versions of the [[High Angle Control System]], or HACS, of [[UK|Britain]]'s [[Royal Navy]] were examples of a system that predicted based upon the assumption that target speed, direction, and altitude would remain constant during the prediction cycle, which consisted of the time to fuze the shell and the time of flight of the shell to the target. The USN Mk 37 system made similar assumptions except that it could predict assuming a constant rate of altitude change. The [[Kerrison Predictor]] is an example of a system that was built to solve laying in "real time", simply by pointing the director at the target and then aiming the gun at a pointer it directed. It was also deliberately designed to be small and light, in order to allow it to be easily moved along with the guns it served.

The radar-based [[SCR-584 radar|M-9/SCR-584 Anti-Aircraft System]] was used to direct air defense artillery since 1943.  The MIT Radiation Lab's [[SCR-584]] was the first radar system with automatic following, [[Bell Labs|Bell Laboratory]]'s M-9<ref>{{cite journal |title=BLOW HOT-BLOW COLD - The M9 never failed|journal=Bell Laboratories Record |date=Dec 1946 |volume=XXIV |issue=12 |pages=454–456 |url=https://www.americanradiohistory.com/Bell_Laboratories_Record_Issue_Key.htm}}</ref> was an electronic analog fire-control computer that replaced complicated and difficult-to-manufacture mechanical computers (such as the Sperry M-7 or British Kerrison predictor). In combination with the VT [[proximity fuze]], this system accomplished the astonishing feat of shooting down [[V-1 (flying bomb)|V-1]] cruise missiles with less than 100 shells per plane (thousands were typical in earlier AA systems).<ref>Baxter, "Scientists Against Time"</ref><ref>Bennett, "A History of Control Engineering"</ref> This system was instrumental in the defense of London and Antwerp against the V-1.

Although listed in Land based fire control section anti-aircraft fire control systems can also be found on naval and aircraft systems.