Power management system and method for vehicle locating unit

• US 8,618,957 B2
• Filed: 10/23/2009
• Issued: 12/31/2013
• Est. Priority Date: 10/23/2009
• Status: Active Grant

• Current Assignee: Calamp Wireless Networks Inc. (CalAmp Corporation)
• Original Assignee: LoJack Corporation (Solera Holdings Incorporated)
• Inventors: Justice, James, Rhodes, Jesse, Goodwin, Michael, Meacci, Fabio
• Primary Examiner(s): Wu, Daniel
• Assistant Examiner(s): Barakat, Mohamed
• Application Number:
  US12/589,498
• Publication Number:
  US 20110095915A1
• Time in Patent Office: 1,530 Days
• Field of Search: 340/988, 340/9.13, 340/10.33, 340/10.34, 340 732- 736, 340/8.1, 340/539.13, 340/539.32, 340/7.34, 340/539.3, 340/539.2, 4553431-3435, 455/572, 455/574, 4554561-457, 370/311
• US Class Current: 340/988
• CPC Class Codes: B60R 25/102 a signal being sent to a remote location, e.g. a radio signal being transmitted to a police station, a security company or the owner
• CPC Class Codes: B60R 25/403 Power supply in the vehicle
• CPC Class Codes: G08G 1/20 Monitoring the location of vehicles belonging to a group, e.g. fleet of vehicles, countable or determined number of vehicles
• CPC Class Codes: H04W 52/0229 where the received signal is a wanted signal
• CPC Class Codes: H04W 52/0235 where the received signal is a power saving command
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

Improved power management for a vehicle locating unit is achieved by receiving a transmission from a communication source, each transmission including at least one message frame having a data field and at least one auxiliary field; entering a wake mode upon indexing the assigned message frame of the receiver in the transmission; matching the pattern of bits of at least one auxiliary field of the indexed frame with one or more stored patterns of bits expected for that auxiliary field; and returning to the sleep mode as soon as a mismatch is determined or processing the message if no mismatch occurs.

Claims

1. A vehicle locating unit with improved power management, the vehicle locating unit comprising:

a receiver for receiving an intermittent transmission from a communications source and having an assigned message frame, each transmission including at least one message frame having a data field and at least one auxiliary field; and

a power management system responsive to said receiver and configured to perform the following sequential steps;

(i) enter a wake mode corresponding to an expected start of the intermittent transmission,

(ii) enter a sleep mode until a start of a next intermittent transmission if the expected start of the intermittent transmission is not detected;

otherwise, after detecting the expected start of the intermittent transmission, re-enter sleep mode and index to the receiver'"'"'s assigned message frame in the intermittent transmission,

(iii) re-enter the wake mode after indexing,

(iv) match a pattern of bits of the at least one auxiliary field of the indexed message frame with a plurality of stored patterns of bits, each pattern of bits corresponding to a command to the vehicle locating unit, and

(v) return to the sleep mode if a mismatch is detected.

2. The vehicle locating unit of claim 1 in which there are a plurality of message frames in each transmission.

3. The vehicle locating unit of claim 1 in which there are one or more auxiliary fields in each message frame.

4. The vehicle locating unit of claim 1 in which said power management system includes a processor for controlling said wake and sleep modes.

5. The vehicle locating unit of claim 1 in which said power management system includes a memory for storing said plurality of patterns of bits expected for an auxiliary field.

9. The vehicle locating unit of claim 1 further comprising:

a transmitter for transmitting reply codes;

wherein the periodic, intermittent transmission includes at least one of an activate command, a de-activate command, and a speed-up command, the receiver further adapted to wake up at a start of the periodic intermittent transmission; and

the power management system responsive to said receiver is configured to switch said transmitter from a de-activated state to a slow mode state upon receipt of an activate command, to switch said transmitter from said slow mode state to a second, slower, slow mode state after a predetermined period; and

upon receipt of a speed-up command to switch said transmitter from either of the slow mode state or second slow mode state to a fast mode state and to switch said transmitter from the fast mode state to said slow mode state after a predetermined period.

10. The vehicle locating unit of claim 9 in which said power management system is further configured to switch said transmitter from said second slow mode state to a third, slower, slow mode state after a preselected period, and to switch said transmitter from said third slow mode state to said fast mode state upon receipt of a speed-up command.

11. The vehicle locating unit of claim 10 in which said power management system is further configured to de-activate said transmitter from any of said mode states to a de-activated state upon receipt of a de-activate command.

6. An improved method of power management for a vehicle locating unit having a receiver, the method comprising:

assigning a message frame to the receiver;

receiving an intermittent transmission from a communication source, each transmission including at least one message frame having a data field and at least one auxiliary field;

entering a wake mode corresponding to an expected start of the intermittent transmission;

entering a sleep mode until a start of a next intermittent transmission if the expected start of the intermittent transmission is not detected;

otherwise, after detecting the expected start of the intermittent transmission, re-entering sleep mode and indexing to the receiver'"'"'s assigned message frame in the intermittent transmission;

reentering the wake mode after indexing to the assigned message frame in the intermittent transmission;

matching a pattern of bits of the at least one auxiliary field of the indexed frame with a plurality of stored patterns of bits, each pattern corresponding to a command to the vehicle locating unit; and

returning to the sleep mode if a mismatch is detected.

7. The improved method of power management of claim 6 in which there are a plurality of message frames in each transmission.

8. The improved method of power management of claim 6 in which there are one or more auxiliary fields in each message frame.