Expanding time window for remote commands

Patent metadata

Field	Value
Publication number	US-9959690-B2
Application number	US-201615189789-A
Country	US
Kind code	B2
Filing date	Jun 22, 2016
Priority date	Jun 22, 2016
Publication date	May 1, 2018
Grant date	May 1, 2018

Abstract

A vehicle includes: receiver(s), a timer counting time, memory, and processor(s) configured to: receive a timestamped signal from a fob; compare the timestamp to a time window; reject the timestamp if the timestamp is outside the time window; expand the time window with the counted time; compute the time window as a trigonometric function of the counted time and a predetermined angle.

First claim

The invention claimed is:

1. A vehicle comprising:
a receiver, timer counting time, memory, and processor configured to:
receive a timestamped signal from a fob;
compare the timestamp to a time window;
reject the timestamp if the timestamp is outside the time window;
expand the time window with the counted time; and,
compute the time window as a trigonometric function of the counted time and a predetermined angle.

2. The vehicle of claim 1 , wherein the predetermined angle is a maximum divergence angle between the timer and a key fob timer due to non-constant timer skew.

3. The vehicle of claim 1 , wherein the processor is configured to:
synchronize the counted time with the timestamp upon accepting the timestamped signal.

4. The vehicle of claim 1 , wherein the processor is configured to:
enforce a predetermined maximum time window.

5. The vehicle of claim 4 , wherein the processor is configured to:
enable user selection, via a vehicle display, of a maximum resynchronization time and calculate the predetermined maximum time window based on the user selection.

6. A vehicle comprising:
a receiver, timer counting time, memory, and processor configured to:
receive a timestamped signal from a fob;
compare the timestamp to a time window;
reject the timestamp if the timestamp is outside the time window;
expand the time window with the counted time; and,
enable user selection, via a vehicle display, of a maximum predetermined time, compare the maximum predetermined time to the counted time, and when the counted time exceeds the maximum predetermined time, accept the timestamp if the timestamp is outside the time window.

7. The vehicle of claim 6 , wherein the processor is configured to: accept the timestamp if the timestamp is outside the time window only when the counted time exceeds the maximum predetermined time.

8. The vehicle of claim 1 , wherein the timer includes a dedicated battery that exclusively supplies electrical power to the timer.

9. The vehicle of claim 1 , wherein the processor configured to: adjust the counted time to account for constant clock skew.

10. The vehicle of claim 9 , wherein the processor is configured to:
perform the adjustment according to a function learned at a time of initial pairing between the receiver and the fob.

11. The vehicle of claim 10 , wherein the processor is configured to:
compare the timestamp to the time window even after adjusting the counted time to account for constant clock skew.

12. A system comprising:
the vehicle of claim 1 and the fob, which includes a fob timer counting fob time and a dedicated fob battery that exclusively supplies electrical power to the fob timer.

13. The system of claim 12 , wherein the processor is configured to:
synchronize the counted time with the counted fob time upon detecting a wired connection between the fob and the vehicle.

14. A method of controlling a vehicle including: a receiver, timer counting time, memory, and processor, the method comprising, with the processor:
receiving a timestamped signal from a fob;
comparing the timestamp to a time window;
rejecting the timestamp if the timestamp is outside the time window;
expanding the time window with the counted time; and,
enabling user selection, via a vehicle display, of a maximum predetermined time, comparing the maximum predetermined time to the counted time, and when the counted time exceeds the maximum predetermined time, accepting the timestamp if the timestamp is outside the time window.

15. The method of claim 14 , including:
configuring the processor to automatically account for constant timer skew from both of the vehicle timer and a fob timer.

16. The method of claim 15 , including:
synchronizing the timer with the timestamp upon accepting the timestamp.

17. The method of claim 16 , including:
computing the time window as a trigonometric function of the counted time and a predetermined angle.

18. The method of claim 17 , wherein the computing of the time window as a trigonometric function of the counted time and a predetermined angle includes:
finding a magnitude of a worst-case skew due to non-constant clock errors between the timer and the fob timer;
setting the time window as twice the magnitude.

Assignees

• Ford Global Tech Llc

Inventors

• Zielinski Mark Andre
• Bielawski Jr John Russell

Classifications

• G07C9/215 Primary

  the system having a variable access-code, e.g. varied as a function of time · CPC title

• H04L9/3297 Primary

  involving time stamps, e.g. generation of time stamps · CPC title

• G07C2209/06

  Involving synchronization or resynchronization between transmitter and receiver; reordering of codes · CPC title

• G07C2009/00849

  programming by learning · CPC title

• G07C9/00174 Primary

  Electronically operated locks; Circuits therefor; Nonmechanical keys therefor, e.g. passive or active electrical keys or other data carriers without mechanical keys (mechanical locks with electric permutation E05B49/00; arrangements for sensing or reading record carriers G06K7/00; electronic switching H03K17/00) · CPC title