GPS based time determining system and method

• US 5,724,316 A
• Filed: 09/26/1995
• Issued: 03/03/1998
• Est. Priority Date: 09/26/1995
• Status: Expired due to Term

• Current Assignee: ValueStreet Consulting Group
• Original Assignee: Delco Electronics Corporation (Motors Liquidation Co. GUC Trust)
• Inventors: Brunts, Randall T.
• Primary Examiner(s): Miska, Vit W.
• Application Number:
  US08/533,904
• Time in Patent Office: 889 Days
• Field of Search: 368/10, 368/46, 368/47, 368/21, 368/22, 340/825.44, 340/825.26, 340/825.47, 340/825.48, 340/825.49, 340/990-995, 340/988, 364/444-452, 342/357, 342/457, 343/225, 455/12, 455/51
• US Class Current: 368/10
• CPC Class Codes: G01C 21/3697 Output of additional, non-guidance related information, e.g. low fuel level G01C21/3679 takes precedence
• CPC Class Codes: G04R 20/06 Decoding time data; Circuits therefor
• CPC Class Codes: G08G 1/096861 where the immediate route instructions are output to the driver, e.g. arrow signs for next turn
• CPC Class Codes: G08G 1/096872 where instructions are given per voice

Abstract

An audio entertainment/navigation system with updated time readings is provided especially for a mobile user. The navigation system receives GPS position information signals which are processed to determine current position latitude and longitude coordinates and direction of travel. A destination database includes a plurality of categorized destinations and corresponding destination position coordinates pertaining to the destinations. The destination database is stored on an interfacable memory card. A time change database is also included which contains time-related information such as time zone boundaries and special time change rules such as daylight saving time. The time-related information may be loaded into the system from an interfacable memory card. A time of day as referenced to a reference time and the date are also computed from the GPS signals. The time and date are compared with the time-related information so as to determine a current updated time and date which is used to periodically update the clock and may be displayed on a display. Also, a user may obtain a current time and date reading for a remote destination by entering the destination name or coordinates into the system.

Claims

1. A method of providing current updated time of day, said method comprising the steps of:

receiving GPS radio wave signals;

determining a current position from said GPS radio wave signals;

determining a reference time of day from said GPS radio wave signals;

providing a clock for providing a measured time;

determining a direction of travel;

determining a speed of travel;

determining an approximate current position as a function of the determined direction and speed of travel when GPS radio waves are unavailable;

determining the current time of day as a function of the approximate current position; and

displaying the determined current time of day.

2. In a GPS navigation and audio entertainment system having navigation control means, display means, a GPS receiver for receiving GPS radio wave signals and processing means for determining a current position, the improvement comprising:

means for determining a reference time of day of said received GPS radio wave signals;

a data base containing time-related information including time zone position boundaries mapped as a function of geographical position coordinates, said time-related information further including rules for defining changes in time;

a clock for providing a measured time of day;

means for determining a direction of travel;

means for determining a speed of travel;

means for calculating an approximate current position as a function of the determined direction and speed of travel when GPS radio wave signals are unavailable and calculating the current time of day for the approximate current position; and

means for periodically updating the clock with the calculated current time of day.

3. A navigation system for use in a vehicle and having a clock which is automatically updated with a measured time of day based on time change boundaries, the system comprising:

a radio wave receiver for receiving a position indicative signal and a reference time;

means for determining a current position of the vehicle from the radio wave signal;

memory containing time-related information including time zone position boundaries mapped as a function of geographical position coordinates, said time-related information further including rules for defining changes in time as a function of the geographical position coordinates;

a clock for providing a measured time of day;

means for determining a direction of travel;

means for determining a speed of travel;

means for calculating an approximate current position as a function of the determined direction and speed of travel when GPS radio wave signals are unavailable and calculating the current time of day for the approximate current position; and

means for periodically updating the clock with the calculated current updated time of day.