Interior rearview mirror system with compass

An interior rearview mirror system for a vehicle, said interior rearview mirror system comprising:

• an interior rearview mirror assembly;
• a casing having a reflective element;
• said casing being adjustable relative to a mounting structure that mounts said interior rearview mirror assembly to an interior portion of the vehicle;
• a compass sensor having a first magnetoresponsive sensing element and a second magnetoresponsive sensing element, said compass sensor being disposed within said mirror casing;
• a control, said control receiving a first signal indicative of a magnetic field sensed by said first magnetoresponsive sensing element, said control receiving a second signal indicative of a magnetic field sensed by said second magnetoresponsive sensing element;
• said control determining a directional heading of the vehicle based on said first and second signals, said control automatically compensating for a deviating magnetic field of the vehicle and generating a signal indicative of the directional heading of the vehicle;
• said control being operable to enter a rapid compensating mode in response to an ignition cycle of the vehicle;
• said control automatically exits said rapid compensating mode and enters a less aggressive calibration mode that distinguishes the Earth's magnetic field from magnetic anomalies and non-abrupt changes in the vehicle magnetic signature;
• and
• wherein said control automatically exits said rapid compensating mode after a predetermined period of time has elapsed since the ignition cycle.

An interior rearview mirror system for a vehicle, said interior rearview mirror system comprising:

• an interior rearview mirror assembly;
• a casing having a reflective element;
• said casing being adjustable relative to a mounting structure that mounts said interior rearview mirror assembly to an interior portion of the vehicle;
• a compass sensor having a first magnetoresponsive sensing element and a second magnetoresponsive sensing element, said compass sensor being disposed at the rear of said reflective element and supported thereby;
• a control, said control receiving a first signal indicative of a magnetic field sensed by said first magnetoresponsive sensing element, said control receiving a second signal indicative of a magnetic field sensed by said second magnetoresponsive sensing element;
• said control determining a directional heading of the vehicle based on said first and second signals, said control automatically compensating for a deviating magnetic field of the vehicle and generating a signal indicative of the directional heading of the vehicle;
• said control determining that said casing is adjusted by an occupant of the vehicle in response to a change in said first and second signals being indicative of an abrupt movement of said casing about said mounting structure by an occupant of the vehicle;
• said control receiving a third signal indicative of an ignition cycle of the vehicle;
• and
• said control being operable to enter a rapid compensating mode to compensate for the mirror adjustment in response to at least one of (a) said control determining that said casing is adjusted by an occupant of the vehicle and (b) said control receiving said third signal indicative of an ignition cycle of the vehicle.