Electronic compass system
First Claim
1. An electronic compass for a vehicle, comprising:
- a magnetic sensor circuit for sensing three perpendicular components of the Earth'"'"'s magnetic field vector, and for generating output signals representing the three sensed components; and
a processing circuit coupled to said magnetic sensor circuit for receiving the output signals, approximating a three-dimensional geometric pattern derived from the three sensed components, computing a heading of the vehicle as a function of at least two of the sensed components while referencing the three-dimensional geometric pattern, and generating a heading signal representing the computed heading.
0 Assignments
0 Petitions
Accused Products
Abstract
An electronic compass system includes a magnetic sensor circuit having at least two sensing elements for sensing perpendicular components of the Earth'"'"'s magnetic field vector. A processing circuit is coupled to the sensor circuit to filter, process, and compute a heading. The processing circuit further selects an approximating geometric pattern, such as a sphere, ellipsoid, ellipse, or circle, determines an error metric of the data points relative to the approximating pattern, adjusts the pattern to minimize the error, thereby obtaining a best fit pattern. The best fit pattern is then used to calculate the heading for each successive sensor reading provided that the noise level is not noisy and until a new best fit pattern is identified. The electronic compass system is particularly well suited for implementation in a vehicle rearview mirror assembly.
-
Citations
41 Claims
-
1. An electronic compass for a vehicle, comprising:
-
a magnetic sensor circuit for sensing three perpendicular components of the Earth'"'"'s magnetic field vector, and for generating output signals representing the three sensed components; and
a processing circuit coupled to said magnetic sensor circuit for receiving the output signals, approximating a three-dimensional geometric pattern derived from the three sensed components, computing a heading of the vehicle as a function of at least two of the sensed components while referencing the three-dimensional geometric pattern, and generating a heading signal representing the computed heading. - View Dependent Claims (2, 3, 4)
-
-
5. An electronic compass for a vehicle, comprising:
-
a magnetic sensor circuit for sensing at least two perpendicular components of the Earth'"'"'s magnetic field vector and for generating output signals representative of the sensed components; and
a processing circuit coupled to said magnetic sensor circuit for receiving the output signals, selecting an approximating geometric pattern that constitutes a best fit to select data points corresponding to the sensed components taken over time, computing a heading of the vehicle as a function of at least two of the sensed components while referencing the selected approximating geometric pattern, and generating a heading signal representing the computed heading. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12, 13)
-
-
14. An electronic compass for a vehicle, comprising:
-
a magnetic sensor circuit for sensing at least two perpendicular components of the Earth'"'"'s magnetic field vector and for generating output signals representative of the sensed components; and
a processing circuit coupled to said magnetic sensor circuit for receiving the output signals, iteratively selecting an approximating geometric pattern by repeatedly comparing and changing the geometric pattern based on the sensed components taken over time, computing a heading of the vehicle as a function of at least two of the sensed components while referencing the geometric pattern, and generating a heading signal representing the computed heading. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21)
-
-
22. An electronic compass for a vehicle, comprising:
-
a magnetic sensor circuit including at least two sensing elements, each for sensing a component of the Earth'"'"'s magnetic field vector that is perpendicular to the component sensed by the other sensor and for generating output data signals representative of the sensed components; and
a processing circuit coupled to said magnetic sensor circuit for receiving the output data signals, associating the output data signals from each of said sensing elements to establish a data point, applying a smoothing filter to smooth the data point by utilizing a weighted average with the most recent data point given a greater weight than prior data points, computing a heading of the vehicle as a function of the most recent data point, and generating a heading signal representing the computed heading. - View Dependent Claims (23, 24, 25, 26, 27, 28)
-
-
29. An electronic compass for a vehicle, comprising:
-
a magnetic sensor circuit for sensing at least two perpendicular components of the Earth'"'"'s magnetic field vector and for generating output signals representative of the sensed components; and
a processing circuit coupled to said magnetic sensor circuit for receiving the output signals, selecting an elliptical approximating geometric pattern, computing a heading of the vehicle as a function of at least two of the sensed components while referencing the elliptical approximating geometric pattern, and generating a heading signal representing the computed heading. - View Dependent Claims (30, 31, 32, 33)
-
-
34. An electronic compass for mounting in a rearview mirror housing of a vehicle, comprising:
-
a magnetic sensor circuit including first and second sensing elements each for sensing substantially horizontal perpendicular components of the Earth'"'"'s magnetic field vector, and a third sensing element for sensing a substantially vertical component of the Earth'"'"'s magnetic field vector, said sensing elements being mounted in the mirror housing and for generating output signals representing the three sensed components; and
a processing circuit coupled to said magnetic sensor circuit for receiving the output signals, determining a tilt angle of the mirror housing by monitoring said third sensing element during travel of the vehicle through a predetermined range of vehicle headings, compensating the sensed components of the first and second sensing elements for the tilt angle of the mirror housing, computing a heading of the vehicle as a function of the sensed components of the first and second sensing elements, and generating a heading signal representing the computed heading. - View Dependent Claims (35, 36, 37, 38, 39, 40, 41)
-
Specification