公开(公告)号：US5581899A

公开(公告)日：1996-12-10

申请号：US211103

申请日：1994-03-15

申请人： Markus Brehler ,  Patrick Feigen

发明人： Markus Brehler ,  Patrick Feigen

IPC分类号： G01C17/38 ,  G01R33/025

CPC分类号： G01R33/025 ,  G01C17/38

摘要： Process for compensating a magnetic interference field in a vehicle having a navigation installation. During a calibration run for initial compensation, a first set of interference field parameters is determined from the measurements of the magnetic field probe (interference field vector V1, axes a, b of the elliptical locus curve E1, oblique position) and transformed onto points of a circular locus curve with the radius a about the origin (0); the distance from the origin (0) and the angle are calculated for each pair of measurements. The calculated radius values and the circularly transformed pairs of measurements (MP) are averaged and entered in their appropriate memory cell in a segmented memory for 360.degree. with a plurality of memory ceils (predetermined angular region). Variant 1: for each segment, the radius difference (.DELTA.a) is determined from the averaged radius values and the radius (a) and filtered; from this the maximum (MAX) is calculated according to direction and magnitude and the new center (M2) of the locus curve (K2) and thus the new interference field vector (V2=V1+V2') are calculated. The distances from the measurement points (MP) are calculated from M2 and compared with the radius; if there is adequately accurate agreement, compensation is carried out with the new interference field vector (V2). Variant 2: a straight line (g) is calculated from the averaged X and Y values by means of linear regression. Their correlation coefficient is determined and compared with an empirically found threshold; if the correlation coefficient is greater than the threshold, the center point (P) of the straight line section (S1,S2) is determined, which is given by the pairs of measurement points (MP). The perpendicular (L) at the center point (P), towards the origin (0), is constructed and the circle radius (a) is plotted, the end point of the radius forming the center (M2) of the new locus curve (circle K2) (new interference field vector V2).