Beacon proximity detection system for a vehicle

• US 4,710,020 A
• Filed: 05/16/1986
• Issued: 12/01/1987
• Est. Priority Date: 05/16/1986
• Status: Expired due to Fees

• Current Assignee: E.T.M. Realty Trust
• Original Assignee: Denning Mobile Robotics, Inc.
• Inventors: Berger, Alan D., George, Robert W. II, Kadonoff, Mark B., Maddox, James F., Benayad-Cherif, Faycal E., Taivalkoski, Amy L.
• Primary Examiner(s): Buczinski, Stephen C.
• Assistant Examiner(s): Wallace, Linda J.
• Application Number:
  US06/864,292
• Time in Patent Office: 564 Days
• Field of Search: 356/1, 356/4, 356/141, 342/46, 901/1, 364/424, 364/444, 180/167, 180/168
• US Class Current: 356/3.13
• CPC Class Codes: G01C 3/22 using a parallactic triangle with variable angles and a base of fixed length at, near, or formed by the object
• CPC Class Codes: G01S 11/12 using electromagnetic waves other than radio waves
• CPC Class Codes: G01S 5/16 using electromagnetic waves other than radio waves
• CPC Class Codes: G08B 13/2494 by interference with electro-magnetic field distribution combined with other electrical sensor means, e.g. microwave detectors combined with other sensor means

Abstract

A proximity detection system for determining the distance between a vehicle and a navigation beacon by resolving the altitude angle between the beacon and the vehicle and determining the distance between them. The system then defines an optimum distance between the beacon and the vehicle and compares the determined distance and the optimum distance to establish any difference between them.

Claims

1. A proximity detection system for determining the distance between a vehicle and a navigation beacon comprising:

detector means, responsive to the beacon, for resolving the altitude angle between the beacon and the vehicle;

means, responsive to said resolved altitude angle and to the height of the beacon, for determining the distance between the beacon and the vehicle; and

means for defining an optimum distance between the beacon and the vehicle and for comparing said determined distance and said optimum distance to establish any difference between them.

2. The proximity detection system of claim 1 further including means for supplying to said means for defining the height of the beacon and an additional known geometric parameter for said optimum distance.

3. The proximity detection system of claim 2 in which said means for defining includes means for generating the difference in distance of the vehicle as a function of said resolved altitude angle, said known geometric parameter and said known height.

4. The proximity detection system of claim 3 in which said additional known geometric parameter is the expected altitude angle between said detector means and the beacon at said optimum distance.

5. The proximity detection system of claim 4 in which said means for defining calculates the difference in position according to the formula:

##EQU7## where delta x is the difference in position, θ

_VE is the expected vertical angle, θ

_VA is the actual vertical angle, and e is the known height of the beacon.

6. The proximity detection system of claim 3 in which said additional known geometric parameter is the expected horizontal distance of said vehicle to the beacon.

7. The proximity detection system of claim 2 in which said means for supplying includes memory means for storing said known height and said known geometric parameter.

8. The proximity detection system of claim 1 in which said detector means includes:

a multisector sensor for sensing a signal emitted by the beacon; and

means responsive to said sensor sectors for generating an angle data signal representative of the angle from said sensor to the beacon in at least the altitudinal dimension.

9. The proximity detection system of claim 8 in which said sensor is a lateral effect photodiode.

10. The proximity detection system of claim 8 in which said detector means further includes means, responsive to said altitudinal angle, for calculating the direction from the sensor to the beacon.

11. The proximity detection system of claim 1 further including means for adjusting the position of the vehicle by the established difference.

12. The proximity detection system of claim 1 further including inclinometer means for sensing deviation of said vehicle from vertical.

13. The proximity detection system of claim 12 in which said means for defining includes means for combining said vertical deviation and said resolved altitude angle with each other and substituting the combined value for said resolved altitude angle to establish the difference in position.

14. A proximity detection system for determining the distance between a mobile robot and a navigation beacon, comprising:

a mobile robot;

detector means, responsive to the beacon, for resolving the altitude angle between the beacon and said robot;

means, responsive to said resolved altitude angle and to the height of the beacon, for determining the distance between the beacon and said robot;

means for defining an optimum distance between the beacon and said robot and for comparing said determined distance and said optimum distance to establish any difference between them.

15. The proximity detection system of claim 14 further including means for adjusting the position of said robot by said established difference.

16. The proximity detection system of claim 14 in which said robot includes a synchro-drive locomotion system.

17. A proximity detection system for determining the distance between a vehicle and a navigation beacon, comprising:

at least one beacon;

detector means, responsive to said beacon, for resolving the altitude angle between said beacon and the vehicle;

means, responsive to said resolved altitude angle and to the height of said beacon, for determining the distance between said beacon and the vehicle; and

means for defining an optimum distance between said beacon and the vehicle and for comparing said determined distance and said optimum distance to establish any difference between them.

18. The system of claim 17 in which said beacon includes means for emitting detectable energy.

19. The system of claim 18 in which said beacon is a point source.

20. The system of claim 18 in which said beacon includes means for producing said energy in a coded signal which uniquely identifies that beacon.

21. The system of claim 20 further including means for supplying the height of that uniquely identified beacon.

22. The system of claim 21 in which said means for supplying includes memory means, disposed in said vehicle, for storing the known height for that beacon.

23. The system of claim 20 in which said detector means includes:

a multisector sensor for sensing the signal emitted by said beacon;

means, responsive to said sensor, for generating a code data signal representative of said coded signal; and

means, responsive to said sensor sectors, for generating an angle data signal representative of the angle from said sensor to said beacon in at least the azimuthal dimension.

24. The system of claim 17 in which said beacon is positioned along the axis corresponding to the intended direction of travel of said vehicle.