Positional accuracy
Posted: Mon Jun 30, 2008 3:08 pm
I use a DL1 for autocross in an A-Stock Honda S2000. The DL1 is mounted just behind the passenger seat in the trunk area, the antenna is mounted on a flat space ahead of the trunk lid. All runs were taken with the top down so there is minimal GPS blockage.
My concern is a large amount of inaccuracy of position. As you can see in the screenshot below, the runs do not overlay very well at all. Is there something that can be done to improve the accuracy or is this an accepted amount of error?
A friend has an identical unit in a Pontiac Solstice, he has similar or worse errors on his runs. We were hoping to use this to see if taking different lines pays off in terms of time, but the positional error is such that you can have a 20' error at any time! Note that there are no trees or other cover anywhere near this (or our primary) site. This error has presented itself on multiple days from sunny to snowing.
Any thoughts?
Screenshot:
http://members.shaw.ca/ckdyck/axvids/PCA_event.jpg
Data log files:
http://members.shaw.ca/ckdyck/axvids/RUN___03.RUN
http://members.shaw.ca/ckdyck/axvids/RUN___04.RUN
Onboard video of the 4th run:
http://www.youtube.com/watch?v=zIMJAUSrb_0&fmt=18
A second question is in regards to graphing parameters. As shown in the screenshot, the steering angle trace covers less than 50% of the white space. Is there any way to make the max/min of the graph match the max/min of the reading? The blank white space effectively cuts the visible resolution in half, making subtle changes invisible. I've tried changing the min/max values in the variable setup with no change in the white space.
Thanks in advance for any help/advice you can offer!
My concern is a large amount of inaccuracy of position. As you can see in the screenshot below, the runs do not overlay very well at all. Is there something that can be done to improve the accuracy or is this an accepted amount of error?
A friend has an identical unit in a Pontiac Solstice, he has similar or worse errors on his runs. We were hoping to use this to see if taking different lines pays off in terms of time, but the positional error is such that you can have a 20' error at any time! Note that there are no trees or other cover anywhere near this (or our primary) site. This error has presented itself on multiple days from sunny to snowing.
Any thoughts?
Screenshot:
http://members.shaw.ca/ckdyck/axvids/PCA_event.jpg
Data log files:
http://members.shaw.ca/ckdyck/axvids/RUN___03.RUN
http://members.shaw.ca/ckdyck/axvids/RUN___04.RUN
Onboard video of the 4th run:
http://www.youtube.com/watch?v=zIMJAUSrb_0&fmt=18
A second question is in regards to graphing parameters. As shown in the screenshot, the steering angle trace covers less than 50% of the white space. Is there any way to make the max/min of the graph match the max/min of the reading? The blank white space effectively cuts the visible resolution in half, making subtle changes invisible. I've tried changing the min/max values in the variable setup with no change in the white space.
Thanks in advance for any help/advice you can offer!