Tracking Speed


#1

There’s been talk of turret tracking speed in other threads, but it occurred to me that, as far as I can tell, only the speed of the target is taken in to account. I then started thinking that really the “speed” that the enemy is moving is the speed of both the attacker and target combined. This is, of course, completely false.

I then realized the true speed that matters is not the speed of the target, but rather the speed that the target is moving IN RELATION to the attacker. If both targets are moving at the same high speed, but they’re both headed the same direction, there’s a net tracking speed of aprox. zero. If they’re moving in exactly opposite directions, there’s a net tracking speed of double the speed of either one. But then it gets more tricky… If the attacker is moving slowly away from the target, and the target is moving perpendicular to the attacker, but is also turning, the attack speed must be a calculation of the movement of the attacker in relation to the movement of the target. I’m sure there’s a geometric equation to do this that I learned in geometry and just cannot remember, but I wonder, is this how GSB is doing it? If not, would it be cool?


#2

From a fire control standpoint, particularly at the ridiculously short ranges of GSB (shorter than modern land warfare combat, lol), the only thing that matters is CROSSING movement, actually. The apparent movement of the target as seen in 2D from the shooter, the distance, Z, doesn’t matter at all.


#3

For any weapon in motion with a time of flight consideration, it isn’t a geometric equation, it’s actually a differential equation.

From a fire control standpoint, you not only have to calculate where your target is and its relative motion, but where YOU are going to be when you shoot and then how to get your shot (along with all of the ballistic variables) to intersect with your target. Early in the 20th century, battleships used “tables” and analog MECHANICAL computers known as fire control clocks to perform these calculations. To get a valid fire control solution, the firing ship had to maintain a relatively stable course, which is one reason the “battle line” still existed conceptually and in practice. Late WW2, the US integrated radar into their fire control systems along with “stabilized” fire control elements which mean that US battleships no longer had to maintain a steady course and speed to maintain a fire control solution.

In a test, the USS North Carolina actually maintained a valid solution while turning minimum radius “doughnuts” at flank speed. At Surigao Strait, the quantum leap in fire control capability by the US was demonstrated when a line of old US battleships battered IJN Yamashiro into scrap metal in a matter of minutes AT NIGHT, AT RANGE, with considerable background clutter:

[i]"At 03:16, West Virginia’s radar picked up the surviving ships of Nishimura’s force at a range of 42,000 yd (38,000 m) and had achieved a firing solution at 30,000 yd (27,000 m). West Virginia tracked them as they approached in the pitch black night. At 03:53, she fired the eight 16 in (406 mm) guns of her main battery at a range of 22,800 yd (20,800 m), striking Yamashiro with her first salvo. She went on to fire a total of 93 shells. At 03:55, California and Tennessee joined in, firing a total of 63 and 69 14 in (356 mm) shells, respectively. Radar fire control allowed these American battleships to hit targets from a distance at which the Japanese battleships, with their inferior fire control systems, could not return fire.

The other three US battleships, equipped with less advanced gunnery radar, had difficulty arriving at a firing solution. Maryland eventually succeeded in visually ranging on the splashes of the other battleships’ shells, and then fired a total of 48 16 in (406 mm) projectiles. Pennsylvania was unable to find a target and her guns remained silent.

Mississippi only obtained a solution at the end of the battle-line action, and then fired just one (full) salvo of twelve 14 in (356 mm) shells. This was the last salvo ever to be fired by a battleship against another heavy ship, ending an era in naval history.

Yamashiro and Mogami were crippled by a combination of 16 in (406 mm) and 14 in (356 mm) armor-piercing shells, as well as the fire of Oldendorf’s flanking cruisers. Shigure turned and fled but lost steering and stopped dead. Yamashiro sank at about 04:20, with Nishimura on board."[/i]

Diff EQ will melt your brain. It melted mine, and I got an A.

I doubt GSB is solving a differential equation for this, particularly when a % to hit chance random number calc can do the job just fine.


#4

But surely attacker speed should at least be PART of the picture?


#5

I would imagine it is. It certainly complicates fire control in the real world.


#6

Yes, but in the real world time of flight can be meaningful in terms of target cross-sectional areas and target speed. Meaning that you need to move a target at least one cross-section radius during the time of flight to avoid a certain hit.

In the case of lasers and even near-c particle beams, missing in GSB is technically impossible (assuming the “meters” range is considered real. It’s too short if instead of meters you treat it as kilometers, frankly).

At 2000m, evading fire is impossible, period. Even a plain ole rifle bullet moves at 1000m/s. That means at max GSB range, unless the target displaces one cross section radius in 2 seconds, the shot cannot miss. Ever. For a laser it needs to do this in 6x10^-6 seconds (displace itself by one ship radius) to avoid a CERTAIN hit.

I understand “gratuitous,” but IMO a baseline at reality is always a good starting point.

If we assumed the GSB ranges were megameters instead of meters, max range would be 3 light seconds right now (2000 MM). That at least makes misses at max range plausible.


#7

If I understand you correctly, you’re assuming the turret has computed a correct firing solution to begin with. I’m just saying it would seem to me to be cool if the speed used to determine if a turret hits or misses should take both the speed of the attacker and target into account… That’s really it…


#8

What all you lot are overlooking are a number of common, far-future technologies in use by all space-faring species. Quantum evasion, anticipatory glitch auto-steering, plain old chaff and ecm, reciprocal spatial lensing, and of course S.O.* quotient particulator membranic anti-targeting hull coatings. Sure, if we stuck an M1A1 Abrams up there, it could shoot much farther than we see in GSB, but against GSB technology the poor Abrams just wouldn’t see anything to shoot at.

*Space Opera (of course)


#9

As ive said before, lasers require stable platforms to fire correctly. Add that into the equation for firing solution, and you could have all sorts of problems.

Also, the gunners could be gratuitously drunk. Or looking into the sun. Or blind as most sci fi ships have windows, and the light from a sun should hurt a creature that evlolved on a planet.


#10

I am 95% sure this is true of all plasma gunners.


#11

As an aspiring plasma gunner, I resent that remark! You people have no appreciation for the complexity of our jobs! I have a big red button that I push that causes the computer to acquire a firing solution. That button doesn’t push itself, buddy! sigh I can’t take this anymore. I’ll be at the pub… =p