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Precision and Accuracy in the call for fire

Infanteer

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GnyHwy said:
Found some stuff on gyrocompasses.  Originally used in the Navy in WWI, and eventually used by the Airforce in WWII.  Still looking for the first time it was used for artillery orientation.

It'd be interesting seeing the link between the Navy and the Artillery on this one (thesis topic!) - with the later-Dreadnoughts having 15-inch guns, there has to be some science to shooting that caught the Artillery's attention when they started getting real range.
 

Old Sweat

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Infanteer said:
It'd be interesting seeing the link between the Navy and the Artillery on this one (thesis topic!) - with the later-Dreadnoughts having 15-inch guns, there has to be some science to shooting that caught the Artillery's attention when they started getting real range.
Which is why I suggested checking for coastal artillery material. All the problems of naval gunnery except for a moving platform had to be solved. It is interesting that as the range of guns increased, the number used decreased but the effectiveness increased. The same point could be made for naval weapons.
 

TangoTwoBravo

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Going through some of my notes, I found a few passages making references to the equipment useed for indirect artillery fire in the Russo-Japanese War. A British observer noted that the Russian batteries were equipped with telephones by which the observing post could communicate with the guns. The British reports go on to suggest that "this method (indirect fire) ought to be largely practiced by field artillery." Similar observations were made regarding Japanese artillery employing telephones.

Another book makes reference to "gonimetric sights" being developed shortly after "quick-firing" guns appeared (but perhaps it was at the same time, or the technology was married up to the new guns). I think that these are panoramic sights.
 

Kirkhill

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Infanteer said:
It'd be interesting seeing the link between the Navy and the Artillery on this one (thesis topic!) - with the later-Dreadnoughts having 15-inch guns, there has to be some science to shooting that caught the Artillery's attention when they started getting real range.

I think Infanteer may be on to something there.  The RN's battleship gunners, in four separate gun positions, all fought blind.  They were all given individual laying instructions from a Gunnery/Direction/Control?? Officer positioned high on a mast above the Bridge and equipped with a mechanical computer.  Instructions,  I believe,  were passed internally by sound telephones.  For fleet actions the communications were either by wireless (the RN was an early adopter) or by Aldis Lamp.

It might also be interesting to check on the role of the Heliograph, which permitted long range communications in the pre-wireless days (ca 1850-1914).
 

GnyHwy

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Tango2Bravo said:
Going through some of my notes, I found a few passages making references to the equipment useed for indirect artillery fire in the Russo-Japanese War. A British observer noted that the Russian batteries were equipped with telephones by which the observing post could communicate with the guns. The British reports go on to suggest that "this method (indirect fire) ought to be largely practiced by field artillery." Similar observations were made regarding Japanese artillery employing telephones.

Another book makes reference to "gonimetric sights" being developed shortly after "quick-firing" guns appeared (but perhaps it was at the same time, or the technology was married up to the new guns). I think that these are panoramic sights.

Wiki mentions the invention of the lining-plate in 1890 by the Germans. This in my mind is the first goniometer, which eventually evolved into current survey intruments and panoramics.

Wiki also mentions' "The earliest example of indirect fire adjusted by an observer seems to be during the defence of Hougoumont in the Battle of Waterloo where a battery of the Royal Horse Artillery fired an indirect Shrapnel barrage against advancing French troops using corrections given by the commander of an adjacent battery with a direct line of sight.[7]"
http://en.wikipedia.org/wiki/Indirect_fire#History
From this reference.  Against All Odds!: Dramatic Last Stand Actions; Perret, Brian; Cassell 2000; ISBN13: 9780304354566: discussed during the account of the Hougoumont action.

Still looking for field artillery gyros, prior to the US Army PADS in 85.
 

GnyHwy

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The Navy gyrocompass discussion is interesting.  The first use of gyros by them was for WWI, but I am quite certain it was just for navigation (just because a magnetic compass doesn't work too well in a metal ship).  Just like the Airforce using them in WWII, they were just for navigation.

Not sure when the Navy started using them for firing solutions.  It may not have been necessary if the observer in the crow's nest had good visibility.  Even over long ranges, it could still be considered a direct fire mission and the elevation would be much, much more difficult to determine than the orientation.  The orientation would be easy. In line? Check.  Guessing range for correction at 10 NM plus would be unbelievably hard; and without the help of any recognizable features to help judge distance.

Edited to Add:  The best way to judge distance would likely have been to know the length or width of the ship you were up against.  By determining the FOV that it fit into within your telescope, you could probably be fairly accurate with distance.  Range=length or width of target/mils or degrees in the telescope.  Judging the corrections after that would still be very difficult.
 

Old Sweat

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I have a book in my library that I spent 20 bucks on in the early seventies when a nice house went for 40 grand called Guns at Sea by Peter Padfield. It has a very good explanation of solving the various parts of the gunnery problem. Around 1905 the RN had got a lot of it right, but it still was pretty basic. You might be able to get it through the library system.
 

Rifleman62

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To add on, Guns At Sea is available from various sources including here: http://www.abebooks.com/9780238789458/Guns-Sea-Padfield-Peter-0238789454/plp
 

GnyHwy

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Looking for opinions.  Where do you draw the line that defines accuracy in FOO locating devices?

There are many devices out there that all do much of the same thing, but the general relation is, the more accurate, the more cumbersome.  i.e. The GLPS is the most accurate survey/locating device we own, but not practical for FOO/FAC use.

Devices with digital magnetic compasses (DMC) and built in laser range finders (LRF) offer better accuracy than a prismatic or Silva in a highly mobile device, but will be unreliable in highly magnetic areas like modern cities.

Potential solutions are gyros and diff GPS systems that provide <1 mil accuracy.  They are not as mobile as the Vectors or Coral CRC, but will provide guaranteed accuracy as they are not influenced by magnetic interference. 

Gyros have virtually no limitations in accuracy, but size, weight and the fact they have to be tripod mounted is a hindrance; smaller gyro systems that calibrate on the tripod and then switch to DMC for mobility are available.  Diff GPS has the same size and mounting issues, as well as dealing with a GPS denied environment, but they will continue to improve in size as well.  Digital mapping is another solution, but they are also somewhat combersome as you will be hauling around a small laptop, and they don't help in areas that don't have a lot of close proximity reference objects.

So, when trying to engage with GPS guided munitions where do we draw the line for accuracy in the attempts to narrow down the amount of systems we have?  Will a somewhat guaranteed +/- 5 mil work i.e Vectors or Coral CRC?  Do we need < 1 mil accuracy?

For some framework, if targets are within 1km an instrument like the Vectors and giving up a few mils may not be a big deal, assuming your calibration is good, but out beyond that dropping a GPS guided bomb could be a waste.

Thoughts?

 

Old Sweat

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I guess the first question is what kind of accuracy does the FOO need?

I am not going to state the obvious about his own orientation and fixation, but without accuracy here, everything else is pointless. For whatever it is worth, I had a conversation yesterday with a friend who had been in the Airborne Battery when it exercised in the High Arctic. They were subject to large changes in magnetic variation over short distances and used to use devices/techniques such as a gyro, azimuth by polaris and a sun compass. This was in the bad old pre-GPS days, but there may be a hint there. If you wish to explore this, PM me and I will put you in touch.
 

GnyHwy

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Old Sweat said:
I guess the first question is what kind of accuracy does the FOO need?

That is a good question, and as simple as it may sound, is a very complex question.  Situation to situation will dictate and the standard answer of "it depends" does apply, but until we define this, the status quo of digital magnetic compasses (DMC) may have to suffice.

I believe there is somewhat of a blind faith that DMCs are giving correct orientation; "it's digital it must be accurate".  Persons who have done research know this is not true.  When an observer uses a bad direction, even off by 100mils (which is not unlikely), the initial round is off by 100m at 1km.  100mils is very easy to be off, and can easily go unnoticed, until the round hits the ground of course.  Simple magnetic forces such as vehicles, buildings and power lines etc. will make this happen, and with the potential for urban operations ever growing, this becomes even more likely; 100m in a built up area with close proximity friendlies can be a very big deal.

Maybe a better question may be "at what accuracy do we need orientation to be guaranteed"?  If you were to say 20mils, which is the standard arty double check, I would argue that DMCs can't even guarantee that; below 5 mils is barely attainable even in perfect environments.

Gyros and GPS can guarantee less than 5 mil, but they also have their limitations; bulk, vibrations, GPS signal and power requirements are just a few.

Digital mapping is another solution, but again, there are plenty of limitations there as well.

Up north is another can of worms all together.  It would be back to pirate days and sextants for accuracy up there, not to mention that your map is just a sheet of white paper with grid lines on it.
 

GnyHwy

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For the naysayers that believe that the Arty is just an area weapon and that our double checks and "minuscule" calculations are a waste of time or not necessary, tell that to these guys.

Of course the naysayers will chalk it up as a bad target location and dismiss it, but for those of us who know, there are plenty more things that could make this happen. 

Thank goodness those naysayers are a dying breed.

https://www.facebook.com/FUNKER530/videos/932595823458721/?fref=nf
 
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