초록 ▼

An electronic compass system and method in which an automatic calibration process is available while the vehicle is in use. The procedure uses a binning process to collect and count data points which automatically triggers the automatic calibration process, and which is also used for manual calibrat

An electronic compass system and method in which an automatic calibration process is available while the vehicle is in use. The procedure uses a binning process to collect and count data points which automatically triggers the automatic calibration process, and which is also used for manual calibration. Also, there is a procedure for detecting and rejecting anomalous magnetic events outside the vehicle through a jitter phenomenon.

대표청구항 ▼

[ What is claimed is:] [1.] Apparatus for calibrating the distortions in the readings of a magnetic compass having a plurality of magnetic field sensors and for characterizing and rejecting readings caused by transient magnetic disturbances comprising:first means coupled to the compass sensors for o

[ What is claimed is:] [1.] Apparatus for calibrating the distortions in the readings of a magnetic compass having a plurality of magnetic field sensors and for characterizing and rejecting readings caused by transient magnetic disturbances comprising:first means coupled to the compass sensors for obtaining the outputs from each of the sensors as a function of time by weighting and combining the outputs from each of the sensors at a first time and for a predetermined number of the next previous times to said first time to obtain a time filtered output for each of the sensors;second means coupled to said first means to form from said sensors outputs measurement parameters having sensitivity values; said sensitivity values being variables in a generalized equation that represents the configuration and location of a geometrical figure defined by the focus of coordinates of said outputs, said outputs having distortions due to permanent and induced magnetism of the vehicle and distortions due to sensor imbalance between the misorientation of the magnetic compass sensors;said second means for defining calibration coefficients of said measurement parameters in said equation;third means coupled to said second means to incorporate said measurement parameters and said calibration coefficients into a least squares matrix and to solve for said calibration coefficients;fourth means coupled to said third means for computing calibration parameters from said calibration coefficients that are to be applied to said outputs;fifth means coupled to said first means and said fourth means for applying said calibration parameters to said outputs from said f&Art means to form an output from each of two sensors; said two sensors being orthogonally related to one another;sixth means coupled to said fifth means for obtaining the calibrated compass heading from said two sensors outputs; andfurther comprising means for obtaining said outputs separately from said sensors at a selected rate sufficient to characterize the high frequency signature of transient magnetic disturbances and said characterization means further comprising means for analyzing the output separately from each of said sensors by comparing sensor reading magnitudes by application of a selected difference in magnitude as an acceptability threshold and using readings for heading determination which are within the acceptability threshold.