VEHICLE COMPASS SYSTEM WITH HEATED WINDSHIELD COMPENSATION

• US 20150276403A1
• Filed: 03/31/2015
• Published: 10/01/2015
• Est. Priority Date: 04/01/2014
• Status: Active Grant

• Current Assignee: Magna Mirrors of America Incorporated (Magna International Incorporated)
• Original Assignee: Magna Mirrors of America Incorporated (Magna International Incorporated)
• Inventors: Schierbeek, Kenneth L.
• Granted Patent: US 9,587,942 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B60R 1/04 mounted inside vehicle B60R1/025, B60R1/08 take precedence
• CPC Class Codes: B60R 1/12 Mirror assemblies combined with other articles, e.g. clocks
• CPC Class Codes: B60R 2001/1215 with information displays
• CPC Class Codes: G01C 17/28 Electromagnetic compasses with north seeking magnetic elements and having electric pick-offs G01C17/26
• CPC Class Codes: G01C 17/38 Testing, calibrating, or compensating of compasses
• CPC Class Codes: H04N 7/183 for receiving images from a single remote source
• CPC Class Codes: H05B 1/0236 for vehicles

Abstract

A compass system for a vehicle includes a compass sensor and compass circuitry. The compass sensor is disposed at or near an interior heated surface of a windshield of a vehicle equipped with the compass system. The compass circuitry, responsive to an output of the compass sensor indicative of sensed magnetic signals or fields, is operable to determine a directional heading of the vehicle. The compass circuitry is operable to determine a magnetic signature generated by a heating element that heats the interior heated surface of the windshield when the heating element is powered. The compass circuitry, responsive to a determination that the heating element is powered, is operable to compensate the sensed magnetic signals to determine the vehicle directional heading. The compensation is derived from the determined magnetic signature. The compass circuitry may compensate the sensed magnetic signals by applying an offset derived from the determined magnetic signature.

Claims

1. A compass system for a vehicle, said compass system comprising:

a compass sensor disposed at or near an interior heated surface of a windshield of a vehicle equipped with said compass system;

wherein the interior heated surface has a heating element disposed thereat and wherein the heating element is heated by an electrically resistive material of the heating element passing an applied electric current when the heating element is powered;

compass circuitry, wherein said compass circuitry, responsive to an output of said compass sensor indicative of sensed magnetic signals, is operable to determine a vehicle directional heading of the equipped vehicle;

wherein said compass circuitry is operable to determine a magnetic signature generated by the heating element when the heating element is powered; and

wherein said compass circuitry, responsive to a determination that the heating element is powered, is operable to compensate for the magnetic signature generated by the heating element to determine the vehicle directional heading, and wherein the compensation is derived from the determined magnetic signature.

2. The compass system of claim 1, wherein the magnetic signature generated by the heating element is determined periodically.

3. The compass system of claim 2, wherein, responsive to an input indicative of the heating element being powered, said compass circuitry determines a change in sensed magnetic signals and determines an amount of magnetic shift that the heating element generates when the heating element is powered, and wherein said compass circuitry compensates for the magnetic signature generated by the heating element by applying an offset derived from the determined amount of magnetic shift.

4. The compass system of claim 2, wherein, responsive to a determination of the magnetic signature generated by the heating element being affected by other factors, said compass circuitry uses a previously determined compensation.

5. The compass system of claim 4, wherein said other factors comprise at least one of (i) vehicle speed information and (ii) stability of sensed magnetic signals sensed by said compass sensor.

6. The compass system of claim 1, wherein said compass circuitry is operable to adjust the compensation to accommodate variances in current flow through the electrically resistive material of the heating element when the heating element is powered.

7. The compass system of claim 6, wherein said compass circuitry adjusts the compensation responsive, at least in part, to at least one of (i) current flow through the electrically resistive material of the heating element when the heating element is powered, (ii) vehicle battery voltage fluctuation when the heating element is powered, (iii) a temperature exterior of the equipped vehicle at or near the windshield and (iv) vehicle speed.

8. The compass system of claim 1, wherein said compass circuitry is operable to compensate for the magnetic signature generated by the heating element by applying an offset derived from the determined magnetic signature.

9. The compass system of claim 8, wherein said compass circuitry, responsive to the determination that the heating element is powered, is operable to apply said offset to one of (i) the output of said compass sensor and (ii) the determined vehicle directional heading of the equipped vehicle.

10. The compass system of claim 1, wherein said compass sensor is disposed at one of (i) an interior rearview mirror assembly disposed at and behind the interior heated surface of the windshield of the equipped vehicle and (ii) an accessory module disposed at and behind the interior heated surface of the windshield of the equipped vehicle.

11. The compass system of claim 1, wherein a camera views through the interior heated surface of the windshield, and wherein said compass sensor is disposed at or near said camera.

12. The compass system of claim 1, wherein the interior heated surface of the windshield comprises one of (i) a heated localized region at or near said compass sensor and (ii) substantially the entire surface of the windshield.

13. A compass system for a vehicle, said compass system comprising:

a compass sensor disposed at or near an interior heated surface of a windshield of a vehicle equipped with said compass system;

a camera disposed at and behind the interior heated surface of the windshield, wherein said camera views through the interior heated surface of the windshield, and wherein said compass sensor is disposed at or near said camera;

wherein the interior heated surface has a heating element disposed thereat and wherein the heating element is heated by an electrically resistive material of the heating element passing an applied electric current when the heating element is powered;

compass circuitry, wherein said compass circuitry, responsive to an output of said compass sensor indicative of sensed magnetic signals, is operable to determine a vehicle directional heading of the equipped vehicle;

wherein said compass circuitry is operable to determine a magnetic signature generated by the heating element when the heating element is powered;

wherein said compass circuitry, responsive to a determination that the heating element is powered, is operable to compensate for the magnetic signature generated by the heating element to determine the vehicle directional heading; and

wherein said compass circuitry is operable to compensate for the magnetic signature generated by the heating element by applying an offset derived from the determined magnetic signature.

14. The compass system of claim 13, wherein said compass circuitry, responsive to the determination that the heating element is powered, is operable to apply said offset to one of (i) the output of said compass sensor and (ii) the determined vehicle directional heading of the equipped vehicle.

15. The compass system of claim 13, wherein the magnetic signature generated by the heating element is determined periodically, and wherein, responsive to an input indicative of the heating element being powered, said compass circuitry determines a change in sensed magnetic signals and determines an amount of magnetic shift that the heating element generates when the heating element is powered, and wherein said compass circuitry compensates for the magnetic signature generated by the heating element by applying the offset derived from the determined amount of magnetic shift.

16. The compass system of claim 15, wherein, responsive to a determination of the magnetic signature generated by the heating element being affected by other factors, said compass circuitry uses a previously determined offset, and wherein said other factors comprise at least one of (i) vehicle speed information and (ii) stability of sensed magnetic signals sensed by said compass sensor.

17. The compass system of claim 15, wherein said compass circuitry is operable to adjust the offset to accommodate variances in current flow through the electrically resistive material of the heating element when the heating element is powered, wherein said compass circuitry adjusts the offset responsive, at least in part, to at least one of (i) current flow through the electrically resistive material of the heating element when the heating element is powered, (ii) vehicle battery voltage fluctuation when the heating element is powered, (iii) a temperature exterior of the equipped vehicle at or near the windshield and (iv) vehicle speed.

18. The compass system of claim 15, wherein the interior heated surface of the windshield comprises one of (i) a heated localized region through which said camera views and (ii) substantially the entire surface of the windshield.

19. A compass system for a vehicle, said compass system comprising:

a compass sensor disposed at or near an interior heated surface of a windshield of a vehicle equipped with said compass system;

wherein said compass sensor is disposed at one of (i) an interior rearview mirror assembly disposed at and behind the interior heated surface of the windshield of the equipped vehicle and (ii) an accessory module disposed at and behind the interior heated surface of the windshield of the equipped vehicle;

wherein the interior heated surface of the windshield comprises one of (i) a heated localized region at or near said compass sensor and (ii) substantially the entire surface of the windshield;

wherein the interior heated surface has a heating element disposed thereat and wherein the heating element is heated by an electrically resistive material of the heating element passing an applied electric current when the heating element is powered;

compass circuitry, wherein said compass circuitry, responsive to an output of said compass sensor indicative of sensed magnetic signals, is operable to determine a vehicle directional heading of the equipped vehicle;

wherein said compass circuitry is operable to determine a magnetic signature generated by the heating element when the heating element is powered;

wherein said compass circuitry, responsive to a determination that the heating element is powered, is operable to compensate for the magnetic signature generated by the heating element to determine the vehicle directional heading, and wherein the compensation is derived from the determined magnetic signature;

wherein said compass circuitry is operable to compensate for the magnetic signature generated by the heating element by applying an offset derived from the determined magnetic signature; and

wherein said compass circuitry, responsive to the determination that the heating element is powered, is operable to apply said offset to one of (i) the output of said compass sensor and (ii) the determined vehicle directional heading of the equipped vehicle.

20. The compass system of claim 19, wherein said compass circuitry is operable to adjust the compensation to accommodate variances in current flow through the electrically resistive material of the heating element when the heating element is powered, and wherein said compass circuitry adjusts the compensation responsive, at least in part, to at least one of (i) current flow through the electrically resistive material of the heating element when the heating element is powered, (ii) vehicle battery voltage fluctuation when the heating element is powered, (iii) a temperature exterior of the equipped vehicle at or near the windshield and (iv) vehicle speed.