Collision avoidance method and system

• US 6,614,721 B2
• Filed: 10/15/2001
• Issued: 09/02/2003
• Est. Priority Date: 10/13/2000
• Status: Expired due to Term

• Current Assignee: Tag Safety Systems Incorporated
• Original Assignee: Edward Bokhour
• Inventors: Bokhour, Edward
• Primary Examiner(s): Lobo, Ian J.
• Application Number:
  US09/977,858
• Publication Number:
  US 20020067660A1
• Time in Patent Office: 687 Days
• Field of Search: 367/127, 367/128, 367/907, 367/909, 340/10.1, 340/572.1, 340/573.1, 340/825.49, 340/825.72, 340/539
• US Class Current: 367/128
• CPC Class Codes: G01S 11/16 using difference in transit time between electrical and acoustic signals
• CPC Class Codes: G01S 13/74 Systems using reradiation of radio waves, e.g. secondary radar systems; Analogous systems
• CPC Class Codes: G01S 13/931 of land vehicles
• CPC Class Codes: G01S 2013/9324 Alternative operation using ultrasonic waves
• CPC Class Codes: Y10S 367/907 Coordinate determination

Abstract

A presence detection system includes a reader device attached to a first body, and a tag device attached to a second body. The reader device has an ultrasonic transducer for generating and transmitting ultrasonic pulses at a first rate of occurrence; an RF receiver for receiving a RF signal; and a microcontroller coupled to the ultrasonic transducer and the RF receiver for receiving signals from the ultrasonic transducer and the RF receiver and for controlling the operation of ultrasonic transducer and the RF receiver. The tag device has an ultrasonic receiver for receiving ultrasonic pulses from the ultrasonic transducer of the reader device; and an RF pulse generator for generating and transmitting an RF pulse. The microcontroller instructs the ultrasonic transducer to generate and transmit the ultrasonic pulses; the ultrasonic receiver of the tag device receives at least one of the ultrasonic pulses; the ultrasonic receiver triggers the RF signal generator to transmit an RF pulse; the RF receiver of the reader device receives the RF signal; and the microcontroller detects the presence of the tag device based on the reception of the RF pulse. The distance between the reader device and the tag device is determined based on the amount of time between the transmission of the ultrasound pulse by the reader device and the reception of the response RF pulse by the reader device.

Claims

1. A presence detection system comprising:

a reader device attached to a first body, comprising;

an ultrasonic transducer for generating and transmitting ultrasonic pulses at a first rate of occurrence;

an RF receiver for receiving an RF signal; and

a first microcontroller coupled to said ultrasonic transducer and said RF receiver for receiving signals from said RF receiver and for controlling the operation of ultrasonic transducer and said RF receiver; and

a tag device attached to a second body, comprising;

an ultrasonic receiver for receiving ultrasonic pulses from said ultrasonic transducer of said reader device;

an RF pulse generator for generating and transmitting an RF pulse; and

a timing circuit which operates to trigger said RF pulse generator to transmit an RF pulse at a second rate of occurrence, said second rate of occurrence being different from said first rate of occurrence;

wherein;

A. said first microcontroller instructs said ultrasonic transducer to generate and transmit said ultrasonic pulses;

B. said ultrasonic receiver of said tag device receives at least one of said ultrasonic pulses;

C. said ultrasonic receiver triggers said RF signal generator to transmit an RF pulse;

D. said RF receiver of said reader device receives said RF signal;

E. said first microcontroller detects the presence of said tag device based on the reception of said RF pulse; and

F. said timing circuit generates a timing pulse to trigger said RF transmitter to transmit an RF pulse at said second rate of occurrence when said ultrasonic receiver does not receive an ultrasonic pulse from said ultrasonic transducer within a predetermined period of time from the reception of a previous ultrasonic pulse.

2. The system of claim 1 wherein one of said ultrasonic pulses transmitted by said ultrasonic transducer is transmitted at a time τ

₁, and said RF pulse resulting from the reception of said ultrasonic pulse by said ultrasonic receiver is received by said RF receiver of said reader device at a time τ

₂;

wherein said first microcontroller determines a distance D between said reader device and said tag device according to the equation;

3. The system of claim 1 wherein said first rate of occurrence is three pulses per second.

4. The system of claim 3 wherein said second rate of occurrence is one pulse per second.

5. The system of claim 4 wherein said first body is a movable vehicle having said reader device attached thereto.

6. The system of claim 5 wherein said second body is a person having said tag device attached thereto.

7. The system of claim 1 further comprising an alarm device coupled to said first microcontroller, wherein said first microcontroller activates said alarm device upon detecting the presence of said tag device.

8. The system of claim 2 further comprising an alarm device coupled to said first microcontroller, wherein said first microcontroller activates said alarm device upon detecting the presence of said tag device.

9. The system of claim 8 wherein said alarm device includes at least one of a visual indicator of the activation of said alarm and an audible indicator of the activation of said alarm.

10. The system of claim 9 wherein said visual indicator comprises a plurality of LEDs in which the number of LEDs that are triggered increases as the distance between said reader device and said tag device decreases.

11. The system of claim 9 wherein said audible indicator comprises a beeper in which the frequency of beeps output by the beeper increases as the distance between said reader device and said tag device decreases.

12. The system of claim 1 wherein said timing circuit comprises a microcontroller which is programmed trigger said RF pulse generator at predetermined intervals and when said ultrasonic pulse is received by said ultrasonic receiver.

13. A method of detecting the presence of an object comprising:

A. transmitting ultrasonic pulses at a first rate of occurrence from a first location;

B. receiving at least one of said ultrasonic pulses at a second location;

C. transmitting an RF pulse in response to said reception of said ultrasonic pulse at said second location;

D. receiving said RF pulse at said first location; and

E. detecting the presence of said object at said second location based on the reception of said RF pulse at said first location; and

F. generating a timing pulse to trigger the transmission of the RF pulse in Step C at a second rate of occurrence when the reception of an ultrasonic pulse in Step B does not occur within a predetermined period of time from the reception of a previous ultrasonic pulse.

14. The method of claim 13 further comprising determining a distance of said object from said first location based on an elapsed time between said transmission of said ultrasonic pulse from said first location to the reception of said RF pulse at said first location.

15. The method of claim 14 further comprising activating an alarm when said distance between said object and said first location is less than a predetermined range.

16. The method of claim 15 wherein said activating step comprises at least one of illuminating a series of LEDs and activating a beeper.

17. A presence detection system comprising:

a reader device attached to a first body, comprising;

an ultrasonic transducer for generating and transmitting ultrasonic pulses at a first rate of occurrence;

an RF receiver for receiving an RF signal; and

a first microcontroller coupled to said ultrasonic transducer and said RF receiver for receiving signals from said RF receiver and for controlling the operation of ultrasonic transducer and said RF receiver; and

at least two tag devices, each tag device comprising;

an ultrasonic receiver for receiving ultrasonic pulses from said ultrasonic transducer of said reader device; and

an RF pulse generator for generating and transmitting an RF pulse;

wherein;

A. said first microcontroller instructs said ultrasonic transducer to generate and transmit said ultrasonic pulses;

B. said ultrasonic receiver of said tag devices receive at least one of said ultrasonic pulses;

C. said ultrasonic receiver of each of said tag devices triggers its associated RF signal generator to transmit an RF pulse;

D. said RF receiver of said reader device receives said RF pulse from each of said tag devices; and

E. said first microcontroller detects the presence of a closest of said tag devices to said reader device, with range determination based on the elapsed time between transmission of any particular ultrasonic pulse and reception of the first RF response pulse associated with that ultrasonic pulse.

18. A presence detection system comprising:

a reader device attached to a first body, comprising;

an ultrasonic transducer for generating and transmitting ultrasonic pulses at a first rate of occurrence;

an RF receiver for receiving an RF signal; and

a first microcontroller coupled to said ultrasonic transducer and said RF receiver for receiving signals from said RF receiver and for controlling the operation of ultrasonic transducer and said RF receiver; and

a tag device attached to a second body, comprising;

an ultrasonic receiver for receiving ultrasonic pulses from said ultrasonic transducer of said reader device; and

an RF pulse generator for generating and transmitting an RF pulse;

wherein;

A. said first microcontroller instructs said ultrasonic transducer to generate and transmit said ultrasonic pulses;

B. said ultrasonic receiver of said tag device receives at least two of said ultrasonic pulses;

C. said ultrasonic receiver triggers said RF signal generator to transmit a first RF pulse in response to the reception of a first of said ultrasonic pulses;

D. said RF receiver of said reader device receives said first RF pulse;

E. said ultrasonic receiver triggers said RF signal generator to transmit a second RF pulse in response to the reception of a second of said ultrasonic pulses;

F. said RF receiver of said reader device receives said second RF pulse; and

G. said first microcontroller detects the rate of change of the distance of said tag device from said reader device based on a difference between reception times of said first and second RF pulses with respect to the transmission times of the first and second ultrasonic pulses, respectively.