LAND VEHICLE NAVIGATION DEVICE COMPRISING A FILTER UNIT FOR DETERMINING AN OPTIMUM HEADING FROM PRESENTED ORIENTATION SIGNALS, AND FILTER UNIT TO BE USED IN SAID NAVIGATION DEVICE

摘要

Land vehicle navigation device comprising a filter unit for determining an optimum heading from presented orientation signals, and filter unit to be used in said navigation device. In a navigation device for land vehicles the orientation signal which indicates the direction of movement along which the vehicle is moving is measured on the one hand by an electronic compass and on the other hand a further orientation signal is determined from a value for the variation of the orientation determined by wheel sensors. These two orientation signals comprise measuring errors. In order to determine an optimum value from said values for the orientation a digital filter unit is used which comprises low-pass and high-pass filters, respectively. The value for the orientation signal measured by the compass is presented to the input of the low-pass filter and the further orientation signal is presented to an input of the high-pass filter. The filter unit furthermore comprises a control unit which is suitable to generate a filter parameter from received orientation signals and to supply said filter parameter to the low-pass filter and the high-pass filter, respectively. Figure 1