User proximity detection for activating vehicle convenience functions
A convenience controller activates a small zone high precision welcoming detecting function (with high current utilization) in response to a detected arrival of an authorized user into a larger zone low precision approach region around a vehicle (with low current utilization). A short range transmitter broadcasts a polling signal covering the region. The short range transmitter has an approach pending mode wherein the polling signal is broadcast according to a first repetition and a baseline mode wherein the polling signal is broadcast according to a lower repetition. The short range transmitter has a first power drain in the approach pending mode. A wireless communication system is configured to monitor for user activity outside the approach region corresponding to proximity to the approach region. If the short range transmitter is in the baseline mode when the activity is detected, then the short range transmitter switches to the approach pending mode.
1. A method controlling a vehicle welcoming function not including door unlocking, comprising:
broadcasting a polling signal from a short range transmitter in the vehicle covering an approach region using a baseline repetition rate having a first power drain;
detecting user activity outside the approach region via a cellular telephone system coarsely indicative of proximity to the approach region, wherein the detected user activity corresponds to a potential entry into the approach region;
increasing a rate of the polling signal from the short range transmitter to an approach-pending repetition rate in response to the detection of the user activity, wherein the approach-pending repetition rate has a second power drain higher than the first power drain;
receiving a response to the polling signal from a user-carried short range wireless device located within the approach region; and
activating the welcoming function when the response is valid.
2. The method of claim 1 further comprising the step of restoring the short range transmitter to broadcasting the polling signal at the baseline repetition rate if a response to the polling signal is not received within a predetermined period of time after the short range transmitter was activated to broadcast the polling signal at the increased approach-pending rate.
3. The method of claim 1 wherein the short range transmitter is comprised of a low-frequency passive entry transmitter.
4. The method of claim 1 wherein the short range transmitter is comprised of a Bluetooth node.
5. The method of claim 1 wherein the short range transmitter is comprised of a WiFi node.
6. The method of claim 1 wherein the user activity is performed in a cellular phone carried by a user, and wherein the vehicle includes a cellular modem configured to receive a message from the cellular phone that is coarsely indicative of proximity to an approach region.
7. The method of claim 6 wherein the message includes a GPS-monitored location of the cellular phone.
8. The method of claim 1 wherein the welcoming function is comprised of illuminating at least one courtesy light on the vehicle.
9. The method of claim 1 wherein the welcoming function is comprised of adjusting a user-customized vehicle accessory.