Methods for locating a vehicle key fob

1. A method of locating a key fob with respect to a vehicle, comprising the steps of:

(a) periodically broadcasting an interrogation signal from the vehicle using a BLUETOOTH™ Low Energy (LE) protocol;

(b) detecting at the vehicle a BLUETOOTH™ LE response signal from the key fob;

(c) authenticating the key fob using the BLUETOOTH™ LE response signal;

(d) monitoring a position of the key fob using short-range wireless signals communicated between the key fob and the vehicle using the BLUETOOTH™ LE protocol;

(e) when the position of the key fob is within a predetermined distance from the vehicle, activating a receiver configured to operate using an IEEE 802.11 protocol;

(f) detecting a short-range wireless signal communicated between the key fob and a plurality of nodes at the vehicle using the IEEE 802.11 protocol;

(g) calculating the distance of the key fob relative to each of the nodes attached to the vehicle based on the detected short-range wireless signal; and

(h) determining the location of the key fob based on the distance of the key fob relative to each of the nodes.

2. The method of claim 1 , further comprising the step of determining whether the key fob is located within the vehicle based on the calculations in step (g).

3. The method of claim 1 , wherein step (f) further comprises detecting at each node the short-range wireless signal transmitted by the key fob.

4. The method of claim 1 , wherein step (f) further comprises detecting at the key fob the short-range wireless signal transmitted by each of the plurality of nodes.

5. The method of claim 1 , further comprising the step of detecting an angle at which the short-range wireless signal is received at one or more of the nodes.

6. The method of claim 1 , wherein step (g) is carried out using a lookup table that includes a distance value associated with a plurality of signal strength values.

7. The method of claim 1 , further comprising the step of determining the key fob is within a predetermined range of the vehicle based on the short range wireless signal.

8. A method of locating a key fob with respect to a vehicle, comprising the steps of:

(a) detecting a short-range wireless signal communicated between the key fob and the vehicle using a BLUETOOTH™ Low Energy (LE) protocol;

(b) determining in which of a plurality of virtual zones surrounding the vehicle the key fob is located based on a calculation of the distance between the key fob and the vehicle using the detected short-range wireless signal;

(c) initiating select vehicle functions based on the location of the key fob relative to the plurality of zones;

(d) when the distance between the key fob and the vehicle is within a predetermined range, activating a receiver configured to detect another short-range wireless signal transmitted between the key fob and the vehicle using an IEEE 802.11 protocol;

(e) calculating the location of the key fob, relative to each of a plurality of nodes attached to the vehicle, using the IEEE 802.11 protocol wireless signal; and

(f) determining whether the key fob is located within the vehicle based on the calculations in step (e).

9. The method of claim 8 , further comprising the step of detecting an angle at which the short-range wireless signal is received at one or more of the nodes.

10. The method of claim 8 , wherein step (a), step (d), or both further comprises detecting at each node the short-range wireless signal transmitted by the key fob.

11. The method of claim 8 , wherein step (a), step (d), or both further comprises detecting at the key fob the short-range wireless signal transmitted by each of the plurality of nodes.

12. The method of claim 8 , wherein step (b), step (e), or both are carried out using a lookup table that includes a distance value associated with a plurality of signal strength values.

13. The method of claim 8 , further comprising the step of authenticating the key fob using the short-range wireless signal transmitted by the key fob using the BLUETOOTH™ Low Energy (LE) protocol.

14. The method of claim 12 , further comprising the step of detecting an angle at which the short-range wireless signal is received at one or more of the nodes.

15. The method of claim 12 , wherein step (e) is carried out using a lookup table that includes a distance value associated with a plurality of signal strength values.

16. The method of claim 12 , further comprising the step of authenticating the key fob using the short-range wireless signal transmitted by the key fob using the BLUETOOTH™ Low Energy (LE) protocol.

17. A method of locating a key fob with respect to a vehicle, comprising the steps of:

(a) detecting at a vehicle a short-range wireless signal transmitted by the key fob using a BLUETOOTH™ Low Energy (LE) protocol;

(b) comparing the detected short-range wireless signal to one or more known signal strength thresholds for the BLUETOOTH™ LE protocol;

(c) determining whether the key fob is within a predetermined range of the vehicle based on the comparison in step (b);

(d) initiating an 802.11 receiver using a plurality of nodes at the vehicle when the key fob is within the predetermined range of the vehicle;

(e) calculating the location of the key fob relative to each of the plurality of nodes using an IEEE 802.11 wireless signal received at each node; and

(f) determining whether the key fob is located within the vehicle based on the calculations in step (e).