Mitigation of LF interference from adjacent vehicles also using LF approach detection system

• US 9,405,944 B2
• Filed: 04/25/2013
• Issued: 08/02/2016
• Est. Priority Date: 04/25/2013
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Van Wiemeersch, John Robert, Hille, Kevin Thomas
• Primary Examiner(s): NWUGO, OJIAKO K
• Application Number:
  US13/870,049
• Publication Number:
  US 20140320260A1
• Time in Patent Office: 1,195 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: G06K 7/10069 the collision being resolved in the frequency domain, e.g. by hopping from one frequency to the other frequency hopping or spread spectrum techniques H04B7/00
• CPC Class Codes: G07C 2009/00388 code verification carried out according to the challenge/response method
• CPC Class Codes: G07C 2209/63 Comprising locating means for detecting the position of the data carrier, i.e. within the vehicle or within a certain distance from the vehicle
• CPC Class Codes: G07C 9/00309 operated with bidirectional data transmission between data carrier and locks

Abstract

A system may include at least one antenna and a controller in communication with the antenna. The controller may be configured to establish a pattern for transmitting low frequency challenges; and instruct the first antenna to transmit the low frequency challenges based on the established pattern.

Claims

1. A system comprising:

at least one first antenna;

a second antenna configured to detect low frequency signals not produced by the first antenna;

a controller in communication with the antennas and configured to;

establish a pattern for transmitting low frequency challenges based on the low frequency signals; and

instruct the first antenna to transmit the low frequency challenges based on the established pattern to avoid interference with the low frequency signals.

2. The system of claim 1, wherein the pattern is a random pattern.

3. The system of claim 2, wherein, based on the random pattern, the antenna transmits low frequency challenges at least once every approximately 200 milliseconds to 800 milliseconds.

4. The system of claim 1, wherein the pattern is a time-shifted interval pattern beginning at a predefined time after a trigger event, the trigger event being at least one of a vehicle turn-off indication and a vehicle lock indication.

5. The system of claim 4, wherein the predefined time is approximately 50 milliseconds after the trigger event and, based on the interval pattern, the antenna transmits the low frequency challenges at equal intervals from the predefined time.

6. The system of claim 1, wherein the controller is configured to determine at least one signal offset of at least one of the detected signals and establish the pattern to avoid the signal offset of the detected signal, the signal offset being measures from an initial reference time.

7. A method, comprising:

receiving, at a computing device of a first vehicle, a signal from a second vehicle;

determining a sequence of the received signal;

establishing a pattern for transmitting low frequency challenges based on the sequence of the received signal, wherein the low frequency challenges avoid the determined sequence of the received signal; and

instructing a first antenna to transmit the low frequency challenges based on the established pattern.

8. The method of claim 7, wherein the sequence includes a polling rate and offset, the signal offset being measured from an initial reference time.

9. The method of claim 8, wherein the pattern is a time-shifted interval pattern beginning at a predefined time after a trigger event, the predefined time differing from the offset.

10. The method of claim 9, wherein the antenna is instructed to transmit the low frequency challenges at equal intervals from the predefined time.

11. The method of claim 7, wherein the pattern is a random pattern.

12. The method of claim 11, wherein, based on the random pattern, the antenna transmits low frequency challenges at least once every approximately 200 milliseconds to 800 milliseconds.

13. A method, comprising:

receiving, at a computing device of a first vehicle, a signal from a second vehicle;

determining a location attribute of the second vehicle based on the received signal;

determining whether the location attribute exceeds a predefined threshold; and

in response to the location attribute exceeding the predefined threshold, establishing a pattern for transmitting low frequency challenges.

14. The method of claim 13, wherein the location attribute is at least one of a location coordinate and a signal strength.

15. The method of claim 13, wherein the received signal includes a sequence at which low frequency signals are transmitted from the second vehicle, the sequence having at least one of a polling rate and an offset measured from an initial reference time.

16. The method of claim 15, wherein the pattern is established based on the received signal to avoid the sequence of the second vehicle.

17. The method of claim 16, further comprising instructing a first antenna to transmit the low frequency challenges based on the established pattern.

18. The method of claim 13, wherein the pattern is a time-shifted interval pattern beginning at a predefined time after a trigger event, the predefined time differing from an offset.