"Measured" x and y is the physical error measured by a ruler and "Calculated" x and y is computed error displayed in the LCD on the NXT.
The **Non-systematic** involves variations in the surface and the internal uncertainty of ~2% . These errors are difficult to cope with. However the **systematic** errors involves incorrect definition of the LEGO car parameters and these can be corrected by calibration which is described in the following.
## Calibration of wheel diameter and the track width
![Calibration of LEGO car paramters](https://gitlab.au.dk/rene2014/lego/raw/master/Lesson10/Images/Calibration.JPG)
#### Initial square run with calibrated values
| Parameter | Value |
@@ -86,11 +105,23 @@ The plan is to follow the plan described in .
| Track width | 16.27 cm |
## Position tracking by means of particle filters
Why this behavior?
Quantization error in tacho counter in each step of the trip.
Orientation of back wheel.
500 mm kørt distance. Afstand fra mål ~0.5 mm = dist_err = 0.001