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In naval gunnery, when long-range guns became available, an enemy ship would move some distance after the shells were fired. It became necessary to figure out where the enemy ship, the target, was going to be when the shells arrived. The process of keeping track of where the ship was likely to be was called rangekeeping, because the distance to the target—the range—was a very important factor in aiming the guns accurately. As time passed, train (also called bearing), the direction to the target, also became part of rangekeeping, but tradition kept the term alive. Rangekeeping is an excellent example of the application of analog computing to a real-world mathematical modeling problem. Because nations had so much money invested in their capital ships, they were willing to invest enormous amounts of money in the development of rangekeeping hardware to ensure that the guns of these ships could put their projectiles on target. This article presents an overview of the rangekeeping as a mathematical modeling problem. To make this discussion more concrete, the Ford Mk 1 Rangekeeper is used as the focus of this discussion. The Ford Mk 1 Rangekeeper was first deployed on the in 1916 during World War I. This is a relatively well documented rangekeeper that had a long service life.〔 〕 While an early form of mechanical rangekeeper, it does illustrate all the basic principles.〔The improvements in rangekeeper technology for long range gunnery mainly came in the areas of automated gun steering and the incorporation of better sensors, like radar. The basic equations of fire control remained the same.〕 The rangekeepers of other nations used similar algorithms for computing gun angles, but often differed dramatically in their operational use.〔 〕 In addition to long range gunnery, the launching of torpedoes also requires a rangekeeping-like function.〔The torpedo and long range gun rangekeeping functions are different in terms of scale. For example, a torpedo's time of flight is much longer than that of battleship's main gun projectile. The projectile's advantages in terms of speed and rate of fire make ranging shots possible. A torpedo's time of flight is so long that ranging shots are not feasible. Some (papers ) do address these issues.〕 The US Navy during World War II had the TDC, which was the only World War II-era submarine torpedo fire control system to incorporate a mechanical rangekeeper (other navies depended on manual methods). There were also rangekeeping devices for use with surface ship-launched torpedoes. For a view of rangekeeping outside that of the US Navy, there is a detailed reference that discusses the rangekeeping mathematics associated with torpedo fire control in the Imperial Japanese Navy. 〔 〕 The following discussion is patterned after the presentations in World War II US Navy gunnery manuals. ==Analysis== 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Mathematical discussion of rangekeeping」の詳細全文を読む スポンサード リンク
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