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Launch Monitor Accuracy - Doppler vs Camera

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@blugold's post #845 in this thread made me wonder about accuracy of calculated numbers from camera-based systems like Foresight Sports' GC series vs doppler-based systems like TrackMan.

Admittedly I know absolutely nothing about how any of these systems actually work, so I might be totally inaccurate here. But I understood the post referenced above to say that camera-based systems give more accurate information (at least specific to smash factor derived by ball speed divided by clubhead speed) than doppler-based systems.

My question is whether this is an accurate statement, and if so why?
 
c.a.eleric said:
@blugold's post #845 in this thread made me wonder about accuracy of calculated numbers from camera-based systems like Foresight Sports' GC series vs doppler-based systems like TrackMan.

Admittedly I know absolutely nothing about how any of these systems actually work, so I might be totally inaccurate here. But I understood the post referenced above to say that camera-based systems give more accurate information (at least specific to smash factor derived by ball speed divided by clubhead speed) than doppler-based systems.

My question is whether this is an accurate statement, and if so why?
Click to expand...

I know probably about as much about this as you do so I don't know the answer to your question, but I could see it making some sense. In the case of the GC series the system is placed on the side of the ball where the doppler system is behind the ball. It makes some sense in my mind that being on the side would be more accurate for ball/clubhead speed at impact? Doppler based systems like flightscope and trackman are much better at tracking ball flight where the GC2 is not following the ball flight but is creating one based on calculations at impact? Which is why trackman/flightscope is used primarily outdoors?

I don't understand how any of them work really though its all over my head, but I love to see those numbers haha.
 
I don't know the dirty details about how each work other than one is taking a pic as the ball goes by and the other is using radar to track the ball and needs to see the whole flight and can have settings tweaked to mimic different condition or to optimize for use of range balls and wind.

From my experience being fit on gc2, track,an and flight scope all seem to be within an acceptable tolerance for my numbers.
 
I don't know if it's fair to say one is more accurate than the other. They measure things differently and both have positives and negatives.

For example, GC2/GCQuad will never measure your entire ball flight due to the design limitations of the system. So it will always have to guess at what happened based on math. It cannot account for turf variations or weather. Trackman has to guess too though when you use it indoors. Trackman does not have to guess when outdoors though. If the wind pushed the ball left the radar is going to measure that and give you accurate numbers regardless. I can see this being a big benefit for those looking to see how much their ball flight is influenced by the weather.

As far as the club speed/smash factor statement, the two systems measure club speed at different points. I think that is the common answer regarding the discrepancies seen. It's my understanding (and I could be misinformed) that GC2/HMT measures club speed at the point of impact on the face of the club. I know Trackman measures club speed at the geometric center of the club head. So gear effect or lack-there-of can influence resulting smash factors.

All that being said, FlightScope is using a camera with radar. So they must believe there are some benefits you get with the camera over radar alone.
 
-CRW- said:
So gear effect or lack-there-of can influence resulting smash factors.
Click to expand...

can you expand on this? in my brain, this could result in higher smash factor for poorer quality of strike depending on the design of the head. is that what you're saying here? i want that driver!
 
My understanding as to why gear effect plays a part is due to it causing the head to move differently through impact as opposed to centered contact.

https://mytrackman.com/media/db865dec-50e0-439a-b0fd-c1efd12f27b6/yqpGWA/PDF/3.%20Newsletter/newsletter3.pdf

"However, with the club head speed things are not quite as simple. It might be a surprise to many golfers, but the club head speed actually varies significantly depending on where on the club face you are looking. On average there is a 14% difference between heel and toe speed. This means that if you have 100 mph club head speed in the center of the club face, the speed of the heel will be around 93 mph and the toe 107 mph. This is primarily due to two things: 1) the further distance from grip to the toe of the club compared to the grip to heel 2) the rotation of the club head during the downswing. Likewise, the club head speed low on the club face is higher than high on the club face."
Click to expand...
 
Here's another section of that article that is pertinent:

If the smash factor was calculated from straight theory (last column in table 3): ball speed divided with the club head speed at point of impact, the smash factor producing the highest 150.3 mph ball speed would come out as 1.463.

Since ball speed (together with launch angle and spin rate) is what matters for the ball flight, by using the center of the club face as reference for the club head speed measurement, maximizing your TrackMan™ smash factor means also maximizing your ball speed for a given physical strength.

This means that in the case the ball is impacted towards the toe (higher club head speed) but still with a high COR and no loss of energy due to twisting of the club head during impact, the theoretical maximum smash factor might be 1.48, but the TrackMan™ smash factor could come out higher.
Click to expand...

* To see the chart mentioned, refer to page 3 of the article *
 
emart2173 said:
I don't know the dirty details about how each work other than one is taking a pic as the ball goes by and the other is using radar to track the ball and needs to see the whole flight and can have settings tweaked to mimic different condition or to optimize for use of range balls and wind.

From my experience being fit on gc2, track,an and flight scope all seem to be within an acceptable tolerance for my numbers.
Click to expand...

While it follows the whole ball, neither of those doppler systems are doing so in what you see on the screen. First 40 yards or so.
This comes directly from both Trackman and Flightscope in our meetings with them.
 
JB said:
While it follows the whole ball, neither of those doppler systems are doing so in what you see on the screen. First 40 yards or so.
This comes directly from both Trackman and Flightscope in our meetings with them.
Click to expand...

Thanks for that. I knew it was limited to something but didn't know the specifics. In my experiences around this area there is a good mix of flight scope, track man and gc2 among fitters and for instructors I have been to its either track man or flightscope. Last year for the fall ping upgraded to the new track man from gc2 for their fitters.

From a practice and club dialing in perspective I would love to have the new gcquad but the price range is just too much. I may just wait a find a used gc2 this year
 
JB said:
While it follows the whole ball, neither of those doppler systems are doing so in what you see on the screen. First 40 yards or so.
This comes directly from both Trackman and Flightscope in our meetings with them.
Click to expand...

It depends on where you are hitting outdoors with Trackman:

Last data: distance at which TrackMan last recoded data. If the range is sloping upwards last data should be shorter than carry “ at,” if the range is sloping downwards and the TrackMan radar has a line-of-sight to the landing area last data should be longer than carry “ at”
Click to expand...

http://trackmangolf.com/media/5bf8a...0c5c/-rN_WA/PDF/3. Newsletter/newsletter7.pdf
 
Using the Trackman indoors at Modern Golf I had a smash factor average of 1.52 with driver and even 1.5 with my 33* iron.
That said the distances were bang on what I would normally see on course.

I don't quite understand how it gets the smash factor wrong but gets all the ball data right? What am I missing?
 
ArmyGolf said:
Using the Trackman indoors at Modern Golf I had a smash factor average of 1.52 with driver and even 1.5 with my 33* iron.
That said the distances were bang on what I would normally see on course.

I don't quite understand how it gets the smash factor wrong but gets all the ball data right? What am I missing?
Click to expand...

You should have seen Mwards when we were testing the unit. Then you should have seen their reasoning, which was hysterical.
 
JB said:
You should have seen Mwards when we were testing the unit. Then you should have seen their reasoning, which was hysterical.
Click to expand...
Hmm. I'm not sure what to take away from what I saw. Is Trackman basically neutered indoors? I've hit on Trackman outdoors before and never had that same issue.

For the smash to be way off but the ball data correct I assume the issue is the club head data?
 
ArmyGolf said:
Hmm. I'm not sure what to take away from what I saw. Is Trackman basically neutered indoors? I've hit on Trackman outdoors before and never had that same issue.

For the smash to be way off but the ball data correct I assume the issue is the club head data?
Click to expand...

I can't answer that honestly. Nor do I agree with the above about it calculating the entire flight, especially when it was spitting info out as it landed. I understand why they say it though. I don't think the doppler systems work as well indoors honestly though, but that is just from personal trial and error. Then again, I thought the camera systems worked better overall and I have both.
 
c.a.eleric said:
@blugold's post #845 in this thread made me wonder about accuracy of calculated numbers from camera-based systems like Foresight Sports' GC series vs doppler-based systems like TrackMan.

Admittedly I know absolutely nothing about how any of these systems actually work, so I might be totally inaccurate here. But I understood the post referenced above to say that camera-based systems give more accurate information (at least specific to smash factor derived by ball speed divided by clubhead speed) than doppler-based systems.

My question is whether this is an accurate statement, and if so why?
Click to expand...
Yes, my statement was accurate. Mainly, because I said it and believe it.

300px-Truthiness.png
 
JB said:
You should have seen Mwards when we were testing the unit. Then you should have seen their reasoning, which was hysterical.
Click to expand...

ArmyGolf said:
Hmm. I'm not sure what to take away from what I saw. Is Trackman basically neutered indoors? I've hit on Trackman outdoors before and never had that same issue.

For the smash to be way off but the ball data correct I assume the issue is the club head data?
Click to expand...

Mine was outdoors, and I'm looking at the report now and I had some smash factors above 1.50. Three shots in a row were smash factors all of 1.55. Ball striking superiority at its finest :angel:
 
blugold said:
Yes, my statement was accurate. Mainly, because I said it and believe it.

300px-Truthiness.png
Click to expand...

mods- this thread can be closed lol


Sent from my iPhone using Tapatalk
 
JB said:
I can't answer that honestly. Nor do I agree with the above about it calculating the entire flight, especially when it was spitting info out as it landed. I understand why they say it though. I don't think the doppler systems work as well indoors honestly though, but that is just from personal trial and error. Then again, I thought the camera systems worked better overall and I have both.
Click to expand...

I've only been on Trackman 20-30 times (hitting from a bay out onto a range), but I haven't seen it spit out carry/total as the ball is landing. Several measurements are spit out shortly after the shot, then you can literally watch the software trace the flight on a monitor as it flies, then shortly after the ball stops the system will chirp and then give you the remaining measurements. The tracer for the shot will even appear jagged at first but once the software is done calculating everything it normalizes the line so that it appears uniform. I assume it does that for aesthetic purposes.
 
Last edited:
MWard said:
Mine was outdoors, and I'm looking at the report now and I had some smash factors above 1.50. Three shots in a row were smash factors all of 1.55. Ball striking superiority at its finest :angel:
Click to expand...

My favorite was the person from Trackman trying to explain that to you, like we don't understand club head and ball speed. It was a funny day.
 
JB said:
My favorite was the person from Trackman trying to explain that to you, like we don't understand club head and ball speed. It was a funny day.
Click to expand...

I'd rather them had just said, "hey the software does that from time to time on pretty much dead center hits, especially when we have the wrong ball plugged in." don't try and make up stuff.
 
MWard said:
I'd rather them had just said, "hey the software does that from time to time on pretty much dead center hits, especially when we have the wrong ball plugged in." don't try and make up stuff.
Click to expand...

The next time I met with them, I had another similar situation and I really struggled with it. There are two shaft companies I know that still have one, but have moved to something else over similar issues.

They have marketed the device extremely well.
 
JB said:
The next time I met with them, I had another similar situation and I really struggled with it. There are two shaft companies I know that still have one, but have moved to something else over similar issues.

They have marketed the device extremely well.
Click to expand...

That they have. What's funny is, you never hear about the tour pros using it having that issue :confused2:
 
MWard said:
That they have. What's funny is, you never hear about the tour pros using it having that issue :confused2:
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It's unfortunate that the employee couldn't explain to you why it occurs. Did neither of you read the post as to why it occurs, or do you just not understand it?
 
-CRW- said:
It's unfortunate that the employee couldn't explain to you why it occurs. Did neither of you read the post as to why it occurs, or do you just not understand it?
Click to expand...

Went back and read it again. I understand it, but if it's more likely to happen when it happens on impact towards the toe, why did it happen when my impact was center of the face?
 
MWard said:
Went back and read it again. I understand it, but if it's more likely to happen when it happens on impact towards the toe, why did it happen when my impact was center of the face?
Click to expand...

Where you guys using impact tape to know it was in the center of the face?
 
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