METHOD FOR TRACKING THE POSITION AND THE HEADING OF A VEHICLE USING DEAD RECKONING AND A TRACKING DEVICE FOR CARRYING OUT THE METHOD

Position (xref) and heading (H) of a vehicle are tracked using wheel tick numbers coming from wheel tick units (5a, 5b) at the front wheels (3a; 3b) only from which a velocity (v) and a heading rate (h) are calculated. The calculations are based on an intermediate wheel angle (δ). An exact solution δex for the same depends on the velocities of the left front wheel vl and of the right front wheel vr according to δ ex = arctan ( 2  p a 1 + p 2 + ( 1 - p 2 ) 2 - ( 2  p a ) 2 )   where   p = v l - v r v l + v r . An approximate solution δapp is calculated according to the simpler formula δ app = 1 2  arcsin   2  p a and used wherever its deviation from the exact solution δex is not significant, i.e., where the latter is not larger than a threshold wheel angle δthr. Only for δapp>δthr where the deviation is larger than, e.g., 2° or, preferably, 1°, the wheel angle according to the exact solution δex is used. The latter is determined in that the approximate solution δapp is first established and the corresponding exact solution δex read from a look-up table, interpolation being used if necessary.