basic question regarding lateral accel map

Any discussion on using LapTimer. Please use this forum in case you need guidance on how to use LapTimer or perform a certain operation
Post Reply
ridewhencan
Fewer than 10 Posts
Fewer than 10 Posts
Posts: 1
Joined: Thu Jan 04, 2018 11:56 pm

basic question regarding lateral accel map

Post by ridewhencan » Fri Jan 05, 2018 6:26 am

I've been using the laptimer for a couple of years but really only for total laptime. My goal for the upcoming year is to better understand it's functionality, which based on today's reading I can see is extensive. My basic question is this, when looking at practically identical laps, on from 4/2017 and the other from 7/2017, the first lateral exceleration is yellow then red in only one section (the left hander at Lime Rock Park) and on the second one each turn is yellow, red, yellow. The charts are practically identical. I believe both times the iphone was in the Miata's center console, (I use a Mobius for vid) but I will be mounting on the window going forward. What would cause the difference? GPS connection?
User avatar
Harry
Site Admin
Site Admin
Posts: 9583
Joined: Sun Sep 12, 2010 10:32 am
Location: Siegum, Germany
Contact:

Re: basic question regarding lateral accel map

Post by Harry » Thu Jan 11, 2018 12:02 pm

The colors are derived from lateral G with certain thresholds:
  • 0 G - 1 G ‣ green, 1 G - 1.25 G ‣ yellow, 1.25 G and beyond ‣ red
For the standard GPS update rate (1 Hz) and tight corners, it is well possible, you get direct transitions from red to green. If for example one measurement is at 1.3 G and the next one is 0.9 G, you will get this transition. You will not see this for higher update rate GPSs (more positions stored) or longer bends with lower G volatility.

The next LapTimer version 22 (Spring 2018) will come with configurable storage rates (GPS Rate, 5 Hz, 10 Hz, 20 Hz). This will allow recording or acceleration data at a higher rate compared to GPS.

- Harry
Image Image Image Image
Bobl36
10 or more Posts ★
10 or more Posts ★
Posts: 12
Joined: Sat Oct 17, 2015 5:50 pm

Re: basic question regarding lateral accel map

Post by Bobl36 » Mon Mar 05, 2018 11:53 pm

Harry, Your response also answered one of my questions as well. However i still have little idea of how to read and apply the info from other graphs and charts. Can you, or one of your more accomplished users, put together a resource for some of us who may need to actually use all data available to us?
Thank you
Bobl36
User avatar
Harry
Site Admin
Site Admin
Posts: 9583
Joined: Sun Sep 12, 2010 10:32 am
Location: Siegum, Germany
Contact:

Re: basic question regarding lateral accel map

Post by Harry » Tue Mar 06, 2018 12:00 am

Please try the Train the Trainer document available from www.gps-laptimer.de/documentation. It is a bit dated but has a section on how to read various charts.

Harry
Image Image Image Image
Post Reply