Speed going negative when coming to a stop
Posted: Sun May 18, 2014 2:28 am
I'm using the lap timer V18 with a GoPoint BT1 ODB dongle, when the car comes to a stop, the reported wheel speed looks like its going negative, but this is being reported as a large positive speed, like 6553.5km/h (I assume this is -0.1km/h). I hadn't noticed this prior to today because the interesting lap data doesn't usually involve coming to a stop. Today I was practicing with a new XGPS160 (at 10Hz) unit while driving on the street. Looking at old data it seems this has happened previously (using an XGPS150 at 5Hz).
When this happens it makes the speed chart for the lap useless, as the trace is all along the x axis, with a spike up to 4000mph occasionally. I think I may have noticed this once or twice previously, but not realised why there was the glitch in the data.
Here's an extract of the data, coming to a stop.
When this happens it makes the speed chart for the lap useless, as the trace is all along the x axis, with a spike up to 4000mph occasionally. I think I may have noticed this once or twice previously, but not realised why there was the glitch in the data.
Here's an extract of the data, coming to a stop.
Code: Select all
351 17-May-14 22:55:04.9 246.7 37.391555 -122.072993 0 0 13.9 45.603675 331.7 1 2 14 1.01 3 2.8209 1.752826 1 0.05 -0.09 37.391544 -122.073018 840 -3 2.27 2.9 1.801976 0.03 0 0.6 88 0 27 0
351 17-May-14 22:55:05.0 246.8 37.391555 -122.072993 0 0 13.9 45.603675 331.7 1 2 14 0.79 2.3 2.821 1.752888 1 0.05 -0.09 37.391544 -122.073018 876 36 2.27 0.5 0.310686 1 0 0.6 88 0 27 0
351 17-May-14 22:55:05.1 246.9 37.391555 -122.072993 0 0 13.9 45.603675 331.7 1 2 14 0.79 2.3 2.8211 1.75295 1 0.04 -0.09 37.391546 -122.073013 884 8 2.27 6553.5 4072.156094 1 6 0.6 88 0 27 0
351 17-May-14 22:55:05.2 247 37.391555 -122.072993 0 0 13.9 45.603675 331.7 1 2 14 0.79 2.3 2.8212 1.753012 1 0.04 -0.1 37.391546 -122.073013 871 -13 2.8 1.9 1.180605 0 0 0.6 88 0 27 0
351 17-May-14 22:55:05.3 247.1 37.391555 -122.072993 0 0 13.9 45.603675 331.7 1 2 14 0.79 2.3 2.8213 1.753075 1 0.04 -0.1 37.391546 -122.073013 879 8 2.5 6553.5 4072.156094 0 6 0.6 88 0 27 0
351 17-May-14 22:55:05.4 247.2 37.391555 -122.072993 0 0 13.9 45.603675 331.7 1 2 14 0.79 2.3 2.8214 1.753137 1 0.04 -0.1 37.391546 -122.073013 883 4 2.5 6552.9 4071.783271 0 6 0.6 88 0 27 0
351 17-May-14 22:55:05.5 247.3 37.391555 -122.072993 0 0 13.9 45.603675 331.7 1 2 14 0.79 2.3 2.8215 1.753199 1 0.04 -0.1 37.391546 -122.073013 825 -58 2.5 6552.8 4071.721134 0 6 0.6 88 0 27 0
351 17-May-14 22:55:05.6 247.4 37.391555 -122.072993 0 0 13.9 45.603675 331.7 1 2 14 0.79 2.3 2.8216 1.753261 1 0.04 -0.1 37.391546 -122.073013 812 -13 2.5 6552.4 4071.472585 0 6 0.6 88 0 27 0
351 17-May-14 22:55:05.7 247.5 37.391555 -122.072993 0 0 13.9 45.603675 331.7 1 2 14 0.79 2.3 2.8217 1.753323 1 0.04 -0.1 37.391546 -122.073013 847 35 2.5 0 0 0 0 0.6 88 0 27 0
).