HLT doesn't record acceleration data when using external GPS

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gplracerx
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Re: HLT doesn't record acceleration data when using external GPS

Postby gplracerx » Mon May 07, 2018 10:22 pm

Circuit Tools doesn't use measured acceleration data. It calculates it from the GPS position data and uses it's own smoothing algorithm. If you look at the exported .vbo file in Notepad or some other text editor, is the acceleration data there? I'm betting not.


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Re: HLT doesn't record acceleration data when using external GPS

Postby svtdoug » Tue May 08, 2018 10:46 pm

I am having the exact same issue - no acceleration data is appearing on video when I use an external GPS - XGPS160. When is this going to be fixed? When is the new version going to be released? Have track day this Saturday.

Doug


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ereynold60
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Re: HLT doesn't record acceleration data when using external GPS

Postby ereynold60 » Wed May 09, 2018 6:31 pm

gplracerx wrote:Circuit Tools doesn't use measured acceleration data. It calculates it from the GPS position data and uses it's own smoothing algorithm. If you look at the exported .vbo file in Notepad or some other text editor, is the acceleration data there? I'm betting not.


OK... I didn't know that. The VBO has columns for lateral and longitudinal G, but they are ZEROs, except for any S/F or split time event, as I noted previously. CSV exports also show ZEROs for acceleration values, except S/F and splits.

Therefore, its a logic error in Laptimer 21.2, where acceleration values are ONLY recorded during an "action event" (S/F, split), and not being recorded with each GPS location when using an external GPS.


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Re: HLT doesn't record acceleration data when using external GPS

Postby godnamnit » Wed May 09, 2018 11:13 pm

Although one could generate acceleration data fron GPS and use smoothing, the main issue is that we can no longer compare this with previous data that was generated using acceleration sensor. Also it's very hard to apply the same amount of smoothing to each lap.
What's important is the delta, not the absolute value itself in order to compare my progress and improvement from past track days. Hence this is a sinificant issue to be fixed as we are in the middle of a track season now.


gplracerx
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Re: HLT doesn't record acceleration data when using external GPS

Postby gplracerx » Thu May 10, 2018 1:02 am

I have an iPhone 5s running iOS 11.3.1, XGPS160 and GoPoint BT1. I usually get accelerometer data with each fix. The times I don't, it's usually related to accelerometer calibration. I use CAM PRESET for calibration. You can check that in the Administration/Settings menu. That preset assumes that the phone is nearly vertical and phone perpendicular to the lineal acceleration axis of the car, not twisted toward the driver. So I would say it's probably a setup error, not necessarily a logic error/bug in the program.


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Re: HLT doesn't record acceleration data when using external GPS

Postby svtdoug » Thu May 10, 2018 2:18 am

I just ran a test on a neighborhood loop. Drove one lap with external GPS - XGPS160 - and no acceleration data showed up for that lap, other than a few small spikes of lateral g.

Then did another lap with internal GPS only - it recorded acceleration data just fine.

Yes, there is sort of a work around, but no where near accurate. To use workaround - Open up the lap without acceleration data, scroll down to Recalculate, press Acceleration. You will then need to slide the smoothing slider up almost all the way to Strong, to get the best results. Apparently this recalculation uses GPS data to approximate the acceleration data, but it is a very rough approximation. Seems to under records lateral G by 15 - 20%.

Keep in mind, this was driving around my neighborhood at 20-25 mph...

Here is a screen shot of the first lap with External GPS:
Screenshot_2018-05-09-17-59-00.png
Screenshot_2018-05-09-17-59-00.png (139.76 KiB) Viewed 284 times


Screen shot of 2nd lap with internal GPS - normal...
Screenshot_2018-05-09-17-59-16.png
Screenshot_2018-05-09-17-59-16.png (155.88 KiB) Viewed 284 times


And here is a screen shot of the 1st lap - after recalculating the acceleration -
Screenshot_2018-05-09-18-06-20.png
Screenshot_2018-05-09-18-06-20.png (164.6 KiB) Viewed 284 times


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Re: HLT doesn't record acceleration data when using external GPS

Postby ereynold60 » Thu May 10, 2018 8:42 pm

gplracerx wrote:I have an iPhone 5s running iOS 11.3.1, XGPS160 and GoPoint BT1. I usually get accelerometer data with each fix. The times I don't, it's usually related to accelerometer calibration. I use CAM PRESET for calibration.


I use the "right-hand drive" preset, but do not get any acceleration data with an external XGPS160 on Android. I have Laptimer 21.2 - what version are you running ?


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Re: HLT doesn't record acceleration data when using external GPS

Postby Harry » Thu May 10, 2018 9:42 pm

Hi guys,

I understand this is an issue with v21.

As written above, sensor fusion has been rewritten for v22 and we will have a focus on this during beta. There is no fixed date for the release yet, it depends on stability we can achieve during beta.

In case you can’t live with the workaround described in this thread and in case you are used to beta testing, you are free to join the beta.

Please consider this thread closed otherwise.

Thanks, Harry


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Re: HLT doesn't record acceleration data when using external GPS

Postby gplracerx » Thu May 10, 2018 11:15 pm

ereynold60 wrote:
gplracerx wrote:I have an iPhone 5s running iOS 11.3.1, XGPS160 and GoPoint BT1. I usually get accelerometer data with each fix. The times I don't, it's usually related to accelerometer calibration. I use CAM PRESET for calibration.


I use the "right-hand drive" preset, but do not get any acceleration data with an external XGPS160 on Android. I have Laptimer 21.2 - what version are you running ?


21.2.

Maybe it's more of a thing with Android.


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Re: HLT doesn't record acceleration data when using external GPS

Postby godnamnit » Tue May 15, 2018 12:38 am

Harry wrote:Hi guys,

I understand this is an issue with v21.

As written above, sensor fusion has been rewritten for v22 and we will have a focus on this during beta. There is no fixed date for the release yet, it depends on stability we can achieve during beta.

In case you can’t live with the workaround described in this thread and in case you are used to beta testing, you are free to join the beta.

Please consider this thread closed otherwise.

Thanks, Harry


Dear Harry,

Please approve my beta request, unless there is a compelling reason not to. I have track days lined up like a conga line to test it out, and I won't complain! :)



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