Passive entry system and method for a vehicle
First Claim
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1. A method for determining the location of a remote transmitter positioned near a vehicle, the method comprising:
- transmitting at least two measuring signals to a remote transmitter, the at least two measuring signals being transmitted from a first and second antenna positioned about the vehicle;
receiving an acknowledgement signal in response to the measuring signal from the remote transmitter, wherein the acknowledgement signal includes a received signal strength indication (RSSI) for each measuring signal received;
establishing an authorization zone using an elliptical shape, the elliptical shape being established using the first antenna to establish a first focus point and the second antenna to establish a second focus point, and the authorization zone having at least one inclusion area and at least one exclusion area, wherein the at least one inclusion and exclusion area are established using the RSSI from each measuring signal received;
determining a constant value using the sum of the distances from the first focus point and second focus point, wherein the constant value is used to define the curvature of the elliptical shape;
determining the location of the remote transmitter by comparing whether the acknowledgment signal indicates that the remote transmitter is positioned within the authorization zone; and
determining that the remote transmitter is located within the at least one inclusion area when the sum of the RSSI from each measuring signal received is less than the constant value.
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Abstract
A passive entry system and method for determining the location of a remote transmitter positioned near a vehicle. The system and method may include an irregularly shaped authorization zone. The authorization zone may be formed using as least three LF antennas. Alternatively, at least two antennas may be used to form at least one elliptically shaped authorization zone. A controller may determine the location of the fob when the fob is physically positioned within the authorization zone.
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Citations
13 Claims
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1. A method for determining the location of a remote transmitter positioned near a vehicle, the method comprising:
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transmitting at least two measuring signals to a remote transmitter, the at least two measuring signals being transmitted from a first and second antenna positioned about the vehicle; receiving an acknowledgement signal in response to the measuring signal from the remote transmitter, wherein the acknowledgement signal includes a received signal strength indication (RSSI) for each measuring signal received; establishing an authorization zone using an elliptical shape, the elliptical shape being established using the first antenna to establish a first focus point and the second antenna to establish a second focus point, and the authorization zone having at least one inclusion area and at least one exclusion area, wherein the at least one inclusion and exclusion area are established using the RSSI from each measuring signal received; determining a constant value using the sum of the distances from the first focus point and second focus point, wherein the constant value is used to define the curvature of the elliptical shape; determining the location of the remote transmitter by comparing whether the acknowledgment signal indicates that the remote transmitter is positioned within the authorization zone; and determining that the remote transmitter is located within the at least one inclusion area when the sum of the RSSI from each measuring signal received is less than the constant value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A system for determining the location of a remote transmitter positioned near a vehicle, the system comprising:
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at least first and second antennas located about the vehicle, the first and second antennas respectively transmitting first and second measuring signals to a remote transmitter; and a controller configured to; receive an acknowledgement signal from the remote transmitter in response to the measuring signal, wherein the acknowledgement signal includes a received signal strength indication (RSSI) for each measuring signal received; establish an authorization zone using an elliptical shape, the elliptical shape being established using the first antenna to establish a first focus point and the second antenna to establish a second focus point, and the authorization zone having at least one inclusion area and at least one exclusion area, wherein the at least one inclusion and exclusion area are established using the RSSI from each measuring signal received; determine a constant value using the sum of the distances from the first focus point and the second focus point, wherein the constant value is used to define the curvature of the elliptical shape; determine the location of the remote transmitter by verifying whether the acknowledgment signal indicates that the remote transmitter is positioned within the authorization zone; and determine that the remote transmitter is located within the at least one inclusion area when the sum of the RSSI from each measuring signal received is less than the constant value. - View Dependent Claims (10, 11, 12, 13)
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Specification