Vehicle locating unit with improved power management method

• US 20090305640A1
• Filed: 08/12/2009
• Published: 12/10/2009
• Est. Priority Date: 05/18/2005
• Status: Active Grant

• Current Assignee: Calamp Wireless Networks Inc. (CalAmp Corporation)
• Original Assignee: LoJack Operating Company, LP (Solera Holdings Incorporated)
• Inventors: Shroud, Ian Christopher, Smith, Gerard Edward, Nguyen, Son, Rhodes, Jesse, Howe, Timothy David, Cletheroe, Daniel Jonathan Finchley, Watson, Nigel James, Krishna, Sampath, Romano, Frank, Greendale, Steven Walter, Crewe, Philip Grahame, Marsden, Mark
• Granted Patent: US 7,853,218 B2
• Time in Patent Office: Days
• US Class Current: 455/67.110
• CPC Class Codes: G01S 13/825 with exchange of information between interrogator and responder
• CPC Class Codes: H04W 52/0245 according to signal strength
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A method of checking messages from a network of communication sources includes initially testing the signal strength of a plurality of communication sources, storing the identity of the communication sources with the two strongest signals, and alternatively entering a sleep mode and a wake-up mode, the wake-up mode synchronized to the communication source with the strongest signal. The method further includes testing the signal strength of one additional communication source, switching synchronization to the additional communication source if said source presents a signal stronger than the signal of a stored communication source with the strongest signal, and replacing the identity of any stored communication source if an additional communication sources tested in sequence presents a signal stronger than the signal of said stored communication source.

Claims

1. A method of checking messages from a network of communication sources, the method comprising:

initially testing the signal strength of a plurality of communication sources;

storing the identity of the communication sources with the two strongest signals;

alternatively entering a sleep mode and a wake-up mode, the wake-up mode synchronized to the communication source with the strongest signal;

testing the signal strength of one additional communication source;

switching synchronization to the additional communication source if said source presents a signal stronger than the signal of a stored communication source with the strongest signal; and

replacing the identity of any stored communication source if an additional communication source tested in sequence presents a signal stronger than the signal of said stored communication source.

2. The method of claim 1 in which there are n communication sources each transmitting a signal at a different time every n seconds.

3. The method of claim 2 in which n is 8.

4. The method of claim 1 including all communication sources in a start-up mode.

5. The method of claim 1 including powering down during the sleep mode and powering up during the wake-up mode.

6. The method of claim 1 in which the checking of messages from a network of communication sources includes improving power management.