Electronic tether

• US 20020190861A1
• Filed: 06/13/2001
• Published: 12/19/2002
• Est. Priority Date: 06/13/2001
• Status: Active Grant

• Current Assignee: Robert E. Wentworth
• Original Assignee: Robert E. Wentworth
• Inventors: Wentworth, Robert E.
• Granted Patent: US 6,529,131 B2
• Time in Patent Office: Days
• US Class Current: 340/568.1
• CPC Class Codes: G08B 21/0216 Alarm cancellation after generation
• CPC Class Codes: G08B 21/0227 System arrangements with a plurality of child units
• CPC Class Codes: G08B 21/023 Power management, e.g. system sleep and wake up provisions
• CPC Class Codes: G08B 21/0263 System arrangements wherein the object is to detect the direction in which child or item is located
• CPC Class Codes: G08B 21/0294 Display details on parent unit

Abstract

Apparatus for determining distance and location of a subordinate unit relative to a master unit. There may be a plurality of subordinate units for a single master unit. Both the master and subordinate unit(s) consist of a GPS receiver, RF transceiver, power supply, electronic compass, user interface and microprocessor. The master unit periodically polls and exchanges data with the subordinate unit via a RF transmission. The master unit processes the data and displays it on a display as distance and direction to a subordinate unit. The subordinate unit also processes data and displays it on a display as distance and direction to the master unit. Additionally, the master unit compares the data to user selectable predefined parameters. If the data is not within those parameters, the master unit initiates an alarm condition at both the master and subordinate unit.

Claims

1. An electronic tether system comprised of a master unit and a subordinate unit which directly interact for the purpose of monitoring distance and location of said subordinate unit with respect to the position of said master unit and the location of said master unit with respect to the position of the subordinate unit.

2. An electronic tether which includes a master unit comprised of a GPS receiver, antenna, transceiver, power supply, electronic compass, visual display, annunciator means, and a user interface for programming.

3. An electronic tether which includes a subordinate unit comprised of a GPS receiver, antenna, transceiver, power supply, electronic compass, visual display, annunciator means and a user interface for programming.

4. A method of placing units into a program mode that facilitate communication between a master unit and at least one subordinate unit of an electronic tether comprising the steps of:

placing into a memory of said master unit a unique address identifier of said subordinate unit that is to be supervised by said master unit;

removing from said memory a unique address of any subordinate unit that is not intended to be used at a given time;

placing into memory of a said subordinate unit a unique address identifier of said master unit to which it is set to respond; and

establishing an acceptable distance and programming such into said master unit, that a said subordinate unit may travel from said master unit before an alert indication is activated.

5. An electronic tether system composed of a master unit and a subordinate unit each capable of receiving signals from GPS satellites, processing said signals, determining the location of each said unit in terms of latitude, longitude and altitude which constitutes data and placing said data in a temporary memory within each both said master unit and said subordinate unit along with a time value.

6. An electronic tether comprising:

a master unit which receives GPS data;

a subordinate unit which receives GPS data, said subordinate unit being spaced from said master unit;

said master unit to directly interact with said subordinate unit to display distance and direction of said subordinate unit relative to said master unit; and

said subordinate unit to directly interact with said master unit to display distance and direction of said master unit relative to said subordinate unit.

7. The electronic tether as defined in claim 6 wherein:

said master unit is comprised of a GPS receiver, antenna, transceiver, power supply, electronic compass, visual display, annunciator means and a user interface for programming.

8. The electronic tether as defined in claim 6 wherein:

said subordinate unit is comprised of a GPS receiver, antenna, transceiver, power supply, electronic compass, electronic visual display, annunciator means and a user interface for programming.

9. The electronic tether as defined in claim 6 wherein:

said master unit to be selectively programmed to a preset allowable distance that said subordinate unit can be located from said master unit.

10. An electronic tether as defined in claim 6 wherein:

upon said subordinate unit exceeding a maximum preset distance from said master unit said subordinate unit will activate an alarm.

11. A method of operating an electronic tether comprising the steps of:

utilizing a master unit;

utilizing at least one subordinate unit;

placing into a memory of said master unit a unique address identifier of said subordinate unit that is to be supervised by said master unit;

placing into a memory of said subordinate unit a unique address identifier of said master unit to which it is set to respond; and

establishing an acceptable distance and programming such into said master unit that a said subordinate unit may travel from said master unit before an alert indication is activated.

12. The method as defined in claim 11 wherein after said establishing step there is included the following additional step;

polling of said subordinate unit by said master unit to determine distance and direction of said subordinate unit from said master unit.

13. The method as defined in claim 12 wherein the polling step includes calculating the distance to be within the preprogrammed safe range and then placing the location of said subordinate unit in temporary memory of said master unit for comparison with the next received location.

14. The method as defined in claim 13 wherein the polling step includes if the calculated distance is greater than the preprogrammed safe range an alert indication is activated on said master unit.

15. The method as defined in claim 14 wherein the polling step includes determining that if said subordinate unit has traveled beyond the preprogrammed safe range that transmitting by way of a transceiver contained within said master unit, an alert signal to said subordinate unit which informs that the subordinate unit has traveled beyond said safe range with the transmission from said master unit containing information that displays on said subordinate unit with this information comprising distance from the master unit and direction to travel to the master unit.

16. The method as defined in claim 11 wherein there is included within said master unit a call signal designed to be transmitted to a specific subordinate unit, and upon activation of same, trigger the alert indication on said subordinate unit will be activated which will also cause the displaying of the distance and direction of travel from the subordinate unit to the master unit.

17. The method as defined in claim 11 which includes programming into said master unit a power down instruction that is to be transmittable to said subordinate unit.

18. The method as defined in claim 11 wherein upon failure by the master unit to receive an acceptable polling response from said subordinate unit that the following steps are caused to occur:

verifying an invalid or missing response by repeating the polling procedure;

comparing the last received and stored GPS data within the master unit with the time of arrival of the signal from the subordinate unit by use of certain algorithms;

initiating an alert signal at the master unit which is transmitted to said subordinate unit;

displaying the last known distance and direction to travel from the master unit to the subordinate unit;

generating an alert signal transmission causing said subordinate unit to display the alert signal along with distance and direction to travel to the master unit based upon the last known coordinates;

continuing to poll the subordinate unit and attempt to acquire new and valid data from said subordinate unit and updating a display within said master unit accordingly; and

resolving the alert condition by receiving acceptable coordinates from new GPS data or by means of acceptable range determination by the time of arrival technique or other alternate measuring solutions.

19. A method which utilizes a master unit and a subordinate unit capable of receiving data from global positioning system (GPS) satellites, processing said data, determining the location of said master unit and said subordinate unit in terms of latitude, longitude and altitude achieving processed data and placing said processed data in temporary memory within said master unit and said subordinate unit along with a GPS time stamp;

as long as said system is instructed accordingly, said system will continuously acquire new GPS data at a predetermined refresh rate;

said new GPS data will also be stored in said temporary memory; and

previously stored GPS data will be erased.

20. An electronic tether system which includes a master unit and a subordinate unit, said method comprising the steps of:

periodically polling said subordinate unit to request said subordinate unit to transmit by way of the radio frequency transmitter its GPS coordinates and the time that said coordinates were received and stored.

21. An electronic tether system which includes a master unit and a subordinate unit, said method comprising the steps of:

receiving said subordinate units radio frequency transmissions by said master unit containing GPS coordinates and a time stamp of said subordinate unit and placing this information in temporary memory.

22. An electronic tether system which includes a master unit and a subordinate unit, said method comprising the step of:

simultaneously employing alternative distance and location determination techniques which include GPS and time of arrival technique where GPS constitutes a global positioning system and time of arrival constitutes time differential of signal transmitted between said master unit and said subordinate unit and return of a signal of said subordinate unit to said master unit.

23. An electronic tether system which includes a master unit and a subordinate unit, said method comprising the steps of:

producing a polling sequence between said master unit and said subordinate unit;

correlating data during a said polling sequence with data that has been stored in temporary memory of a said subordinate unit;

comparing the said correlated date;

determining the most accurate distance and direction of said subordinate unit relative to said master unit; and

if said master unit determines that available GPS information is insufficient or unacceptable, said distance and direction will be based upon an alternate measurement technique.

24. An electronic tether system which includes a master unit and a subordinate unit, said method comprising the step of:

evaluating calculated distance between said master unit and said subordinate unit and if said distance is calculated to be within a preprogrammed safe range, said location of said subordinate unit is placed in temporary memory for comparison with a next received location.