Medic505
Gold $$ Contributor
Easy Greg, easy..... remember, it's not about accuracy, it's about cheese and crackers.
Accuracy of Electronic Targets
- Thread starter goodi
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Ned Ludd
Silver $$ Contributor
I'm not attempting to advocate one system or another. All I'm saying is that the overall [truly documented] error rate for both human pullers and e-targets isn't that high when you consider the number of total shots fired in a match. But in my experience, the question of "best accuracy" would still go to the human puller at this point.
As you know, I've never tried to hide the fact that I don't like shooting on e-targets. But my primary reason for that is not their "accuracy", it's because of how I perceive they change the game in other ways. For example, a 7 second wait (i.e. e-target delay) while the target is pulled by a human puller would be about the best target service most of us ever had, if the human puller could even do it consistently. Nonetheless, if I start worrying about the accuracy of every single shot taken on an electronic target, it would reduce my enjoyment of the sport markedly . So even though I'm not crazy about the implementation of e-targets in F-Class, they're here, and I made the personal choice to participate in spite of my general dislike of them. Even though I have documented a few errant shots during practice with my own ShotMarker system, I will readily accept the scoring results from an e-target system without unnecessary concern until such time as I have solid evidence that a shot was scored incorrectly, something that hasn't happened to me in a match...yet.
Errors at any range are similar it is a set distance. The target doesn't know what distance your shooting at. In my 2018 test the error of .17" was consistent from 300-600 and would have been the same at 1000.
I will accept that in your test the error was consistent from 300-600, you measured it and have now reported it although you did not give details of the conduct of the test which would have been helpful in establishing validity of the data in the event someone would like to do an independent replication of your test.
I did a similar test and got similar results. But I am not ready to say this will be true if others do a similar test. I would like to see statically significant testing to give more confidence in our results. I did a detailed report that could be followed by others if they would like to participate.
I will say, that we can not say, that "it would have been the same at 1000". There would have to be a test to determine that or not.
Also, please explain what you mean by "Errors at any range are similar it is a set distance". I think I understand your meaning but it would be good to know for sure.
Thanks for sharing your test results, this is how we learn. Data is golden, sometimes all we have is opinions but data trumps opinions and you have data.
Best wishes,
Clyde
Monte F
Silver $$ Contributor
From this past Sunday. Looks like it was slightly off center, but negligible error. Carefully set up electronics work very well. We do not have dropped shots or ghost shots since we starting using every other target carrier. I will shoot on pulled or electronic targets that are set up well. The seven second delay is about what I see at SWN with two average pullers.
Attachments
Clyde the test results are on our website but here are the links. At the time I wrote the test there was a maker of a given closed system who was badmouthing SMT and SM pretty hard to gain support for his system so there is some sarcasm in the verbiage I used in writing the reports. Here are the links
The second link is the updated analysis of the error as provided by a fellow HP shooter to match how Elley measures stuff using radial error. The day in question wasn't super windy but it wasn't the best day to get a test showing the nth amount of accuracy with the system. I plan on doing an updated test at 3/5/6 and 10 again here sometime this season.
The statement that the error is the same at all distances is quite easy to make. The target sensors don't know what distance you are at when you fire they only measure a sonic crack. So long as the sonic crack is loud enough to measure, system runs multiple calculations before plotting a placement and they agree its plotted. This doesn't change with distance. The error your measuring isn't does the pin wheel X line up with the pin wheel X on paper but rather does the shot location as measured from the acoustic center line up to the recorded shot locations on the paper as measured from the paper center. If all the distances are the same then we would say there is 0 error. If the target is offset to shoot 1 MOA low on paper but the shot distances from acoustic center are still the same as paper there is still 0 error. On the results above the SD error was 0.17" and this was with the first generation of math that the system was using which SMT even said of the three was the least accurate. In an enclosed testing environment (read tunnel) the Solo has show sub millimeter accuracy. So at any distance there is going to be a SD of 0.17" on this setup/software/weather day at any distance. If you do the match the accuracy actually gets better the farther back you go. I'm just thinking of all the cleans I've missed in offhand.... (sarcasm).
I never said anything about human error in scoring. Please re read it, but again, the error was induced when the target or face was put on. The next target puller doesn’t know so what they score is what they score but is it correct because of the paper?
If you truly measure the rings, you will see what I am talking about.
Here is a good example of what I am talking about.
A official NRA face. It’s pretty obvious the issue.
What if the person lined up the inside of the lines instead of the outside?? The lines from the reface target and original target aren’t even the same.
I have seen and have scored shots that are closer then that but this is one error I am talking about.
Attachments
When you are measuring error you don't measure if it is centered on the paper. You need to figure out where the acoustic center is plot the distance of the shots from where the accoustic center acctually is.
Ned Ludd
Silver $$ Contributor
I knew what you meant and understand your concerns. Your observations regarding the potential scoring issues presented to (and by) human pullers are valid and are something that need to be considered and addressed whenever possible. However, I have seen numerous posts in the past by others advocating the use of electronic targets that would almost lead one to believe humans are barely even capable of providing fair scoring on pulled targets. I don't think the situation with pulled targets is nearly that bad, but I was not specifically replying to your statements, which is why I didn't directly quote your earlier post.
I've encountered the situation you illustrated more than a few times, myself. In the images you showed, it appears to be more than simple misalignment caused by re-facing the target. The scoring rings of the target face and the repair center actually appear to be of different width. Nonetheless, I still believe the human eye is more than capable of resolving such issues and providing a fair score to the shooter. I can only speak for myself, but in such a case I would still use the outermost edge of the scoring ring(s) where they were mis-aligned to judge. If there was any question at all in my mind, the shooter would receive the benefit of the doubt and get the higher score.
As I noted previously, I made the choice to continue participating in F-Class matches using e-targets. I struggled with the notion for some time, but finally caved and bought an e-target for myself. It is an excellent practice tool, but I would personally still rather shoot matches on pulled targets. That's just me. But that is a moot point as my home range has adopted the use of e-targets and they appear to be here to stay. For that reason, I don't agonize over their "accuracy", which was my second point. That would really drive me nuts...well, at least more so than I already am LOL. I certainly pay close attention to the scores the e-targets generate, but providing solid evidence of an obvious scoring error by an e-target system during a match may be difficult, if not impossible, for certain types of scoring errors. Even with a fresh target face, it is not possible to stop the match just to drive down to the pits to check a single target and determine whether the score was "correct". I have noted a couple times during practice that I received a score from the e-target system that was clearly incorrect, as could be proved afterward due to having a fresh target face on it. The system gave me an "8", when there were clearly no bullet holes at all outside the 9-ring, even though the total number of holes on the target face was correct. I can't tell you if that was caused by crosswind at the target face, or some other phenomenon. But if I start thinking too much about the accuracy of every single shot on an e-target system during a match, my performance might start to suffer, and my enjoyment of the sport certainly would. Unfortunately, that is probably not going to mollify anyone that believes they received an unfair score, possibly not winning a match due to an e-target scoring error. Other than constant scrutiny, I'm not really sure how that issue can ever be fully addressed. The error rate for electronic targets (or human pullers) will never be zero, although there is still clearly room for improvement. So at this point I choose not to worry about it too much until presented with clear evidence that a scoring error has occurred due to the e-target system, which may or may not ever happen. That's just how I have decided to deal with this issue.
Thank you so much for sending this. I took a quick look but this will take some time to digest fully.
For the testing that I did the biggest challenge was getting the virtual electronic target congruent with the paper target. Since any error in congruency carries over into the error calculation this is significant and was on the same order of magnitude as the electronic target error. This congruency is not that important in actual usage, just center up with the electronic target and do not worry about what is happening on paper. If I reran the test or did the analysis different there may be a way around this but I did not spent the time to pursue it.
I am still thinking about the error being independent of distance since I had assumed it to be greater with distance but that was just an assumption on my part.
I did testing at 100/200/300/and 600 yards. My 100 yard frame was smaller than the frame that I used at the other ranges so that muddies the water some what.
Thanks again for sharing data. Opinions are not worth much but data is golden.
Agree on all your points. I am in the same boat as you. Many just want to say they aren’t as accurate. In my eyes, both have flaws but some don’t want to admit it.
Everything evolves. It’s just a matter of how efficiently it moves forward.
Besides comparing digital to paper targets, one can get an idea of the actual accuracy of a system and its frame, by changing the microphone order.
One orientation of plugging in the mics will plot shots across a relatively horizontal line and another orientation, vertical. “How” flat the horizontal and vertical lines are goes to the system accuracy that one is getting on a particular frame, with that particular set. Whether the lines are plumb or canted is also reveled. This kind of testing could conceivably lead to favorite versus forlorn targets, though.
A number of clubs have noted the phenomenon of accidentally incorrectly color matching plug inputs but additionally, the results are at least indirectly indicative of a system’s absolute accuracy.
I thought our club’s variance from a flat line at 600 yards was about as good as possible with exceptionally rigid set ups.
One orientation of plugging in the mics will plot shots across a relatively horizontal line and another orientation, vertical. “How” flat the horizontal and vertical lines are goes to the system accuracy that one is getting on a particular frame, with that particular set. Whether the lines are plumb or canted is also reveled. This kind of testing could conceivably lead to favorite versus forlorn targets, though.
A number of clubs have noted the phenomenon of accidentally incorrectly color matching plug inputs but additionally, the results are at least indirectly indicative of a system’s absolute accuracy.
I thought our club’s variance from a flat line at 600 yards was about as good as possible with exceptionally rigid set ups.
I've seen/heard that happen before but with our system using the 8mic carbon fibers the plugs clearly state top right, bottom left, etc. If you go in manually and change sensor mapping you can change the impact points. This use to be something you may do in the early days if you noticed a certain sensor was slow etc., but thankfully didn't have to do that much then and don't anymore.
Chkunz, testing at 100yds is probably the hardest because that is where the accuracy seems the worst because the target is smaller (i.e. .17" is bigger on a 100yd target compared to rings than the 1000yd). To find the center I typically find the shot that is closest to the center, measure that offset, and then take the next closest see if its close and then run with it. Not precise but made sense. The other thing that increases accuracy is having your sensors spread farther apart. Open mic systems are more accurate in the center, so if you have more room in the center the more accurate they are. On our frames then sensors are more of a rectangular arrangement 6' wide but probably 8' (forget the exact dimension) apart vertically. This is so the lower sensors are below the berm but also spreads them apart more. So long as you have the sensor distances the same and measured correctly it doesn't matter on the shape. For example if you say have the sensors mounted 1M apart horizontally and vertically but put in a distance of 2m you change the scaling of the scoring rings and it makes the scoring target 2x as big, or that is what it appeared to be when I was testing all this a couple years ago in my backyard. That is why it is important to have your sensor spacing measured accurately because having the inputted values different than the actual spacing will affect the size of the rings.
The other thing we played around with last year on the ETs was decimal scoring instead of X,10,9, etc. made decimal targets 10.9, 10.8,10.7,...., 9.6, 9.4, etc. Was interesting to see how that changed the outcome of a match as it favors people who shoot center and hold hard. When you have a match where several guys are shooting cleans and high X counts the decimal scoring definitely gave some separation. Not saying this is something that should be done but just opens up all the possibilities of things you can do with ETs.
Running a few tests is kind of like a three shot group. We've run many tests on multiple targets and matches at 300, 600 and 1000 yds over 3 years now. To make this easy as possible I developed an Excel app that plots the shots from the Shotmarker data and overlays it on a picture of the target. The picture is scaled to match the scoring rings and moved around to get the best fit. This makes it easy to find shots that are outliers. We found out a lot of things and the physical setup areas have been covered very well. They account for a large part of the issues we encountered in the early days but the environmental issues affecting accuracy are not as well known.
Wind has the biggest effect. As the wind gets bigger accuracy degrades. It's a physics issue, no way around it. Under ideal conditions at 1K yds almost all shots are less than a bullet diameter from their plotted location. At 15 mph a significant number will be outside a bullet diameter. Head and Tail winds seem to be worse as are switchy winds.
Mike spacing does matter. The smaller the spacing the better. We put two Shotmarkers on one target, one with 6' spacing and one with 4' spacing. The 4' was better under all conditions. It is also easier to hit a mike,
Shots will be missed. On the two mike system one registered 20 shots in a match and the other had 19.
Rifle type matters. F-O is best, Service rifle not so much. Service rifle at 600 on a windy day is not good. Shots are all over the target and the velocity is low.
Distance does matter. 300 yds was good, 1K not as good. This is probably a combination of closer mike spacing, better shot placement (closer to center), higher velocity at the target. Our 300 yd range is more protected so doesn't get as much wind effect.
Here are some example tests:
Wind has the biggest effect. As the wind gets bigger accuracy degrades. It's a physics issue, no way around it. Under ideal conditions at 1K yds almost all shots are less than a bullet diameter from their plotted location. At 15 mph a significant number will be outside a bullet diameter. Head and Tail winds seem to be worse as are switchy winds.
Mike spacing does matter. The smaller the spacing the better. We put two Shotmarkers on one target, one with 6' spacing and one with 4' spacing. The 4' was better under all conditions. It is also easier to hit a mike,
Shots will be missed. On the two mike system one registered 20 shots in a match and the other had 19.
Rifle type matters. F-O is best, Service rifle not so much. Service rifle at 600 on a windy day is not good. Shots are all over the target and the velocity is low.
Distance does matter. 300 yds was good, 1K not as good. This is probably a combination of closer mike spacing, better shot placement (closer to center), higher velocity at the target. Our 300 yd range is more protected so doesn't get as much wind effect.
Here are some example tests:
After reading your report I think I better understand your meaning. That is, the error as measured in inches does increase with distance but when converted to MOA it is approximately the same. Am I understanding you meaning correctly?
The MOA error may be a better way to look at the error for the reasons that you state, but it is probably a mental block for most competitors and especially those who are not as familiar with the math.
As of now the NRA uses 0.25 inches and not MOA. This may be important, but on the other hand it may not be important since the NRA has lost control. Regardless of accuracy, good or bad. clubs are going more and more to the open mike ET systems. Match Directors find it easier to run matches with the ETs and most competitors consider the advantages outweigh the negatives.
The error is a linear measurement that is constant as in our case .17" in the 2018 test from 300-600. The moa changes and actually decrease. 300 error moa is .17/3 where as 600 is .17/6. So just because of ease of calculations .17" error at 100yd is .17 moa because .17/1=.17. Where as the .17" error at 1000 is .017 moa as .17/10= .017 moa
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What do you estimate that your measurement error is?
I am asking what part of the measurements that you recorded for your test do you estimate is your measurement error? If I measure the length of a board with a tape measure, there is some error in my measurement process. If I measure the distance from the center of the target to the shot hole with a scale there is some error in that measurement. All measurements have some error. I am asking what is your estimate of your measurement error for this test.
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