![\"wander\"](\"http:\/\/fll-freak.com\/blog\/wp-content\/uploads\/2013\/07\/wander.png\")
<\/a><\/p>\nAt first glance, this looks ugly in that there is up to nearly\u00a08 meters (24 feet) of variation. But before panicking, perhaps the variation is over a long time. If the variation would stay within a meter over the 90 seconds it takes to make a single run at AVC, the long term wander would be meaningless.<\/p>\n
So the next thing was to plot the difference in the X position at each sample, and the X position 90 seconds ago. I also did the same for the Y coordinate. This would give me an idea how much variation I would see from the start to the end of a run. Here is the data:<\/p>\n
So now it IS time to PANIC. In as little as a 90 second period I can still expect to see +- 4 meters of wander. Some points on the AVC course are not that wide!<\/p>\n So GPS is good for very long term position solutions, affordable IMUs are good for very short time durations (~15 seconds), what is good for the middle ground?<\/p>\n This looks like it is pointing me to a sensor fusion solution. Can I merge GPS, and IMU, wheel encoders, and possibly my SUNDAR into a good position?<\/p>\n <\/p>\n","protected":false},"excerpt":{"rendered":" Towards my goal of entering the AVC competition in 2014, I have been evaluating GPS units. The current model I am looking at is a u-Blox LEA-6H with a patch antenna. The first test I tried was to hold the … Continue reading <\/a><\/p>\n