ELECTRONIC TRACKING LOCATING SYSTEM USING MULTIPLE FREQUENCY, MODULATED, AND TIME DELAYED ULTRASONIC SIGNALS

• US 3,805,227 A
• Filed: 10/03/1972
• Issued: 04/16/1974
• Est. Priority Date: 10/03/1972
• Status: Expired due to Term

• Current Assignee: Intersonics Corporation
• Original Assignee: Robert W. Lester
• Inventors: Lester, Robert W.
• Primary Examiner(s): Farley, Richard A.
• Application Number:
  US05/294,761
• Time in Patent Office: 560 Days
• Field of Search: 340/3C,3E,312,152T,16R 343/6.5SS
• US Class Current: 367/6
• CPC Class Codes: G08B 3/1083 Pager locating systems
• CPC Class Codes: Y10S 16/13 Plastic hinge
• CPC Class Codes: Y10S 367/91 Portable sonar devices

Abstract

An electronic tracking and locating system for automatically locating at least one of a select group of individuals or objects disposed within a selected area of surveillance is disclosed. The system comprises an ultrasonic identification signal generator and transmitter for generating and transmitting the identification signal at one of a plurality of preselected frequencies throughout the selected area of surveillance, the frequency of the signal being unique with respect to the individual or object to be located. Transceivers are disposed remotely from the identification signal generator and transmitter, and are carried by each individual or object within the select group for receiving the identification signal. The transceivers transmit an output signal at a preselected frequency in response to an identification signal having a frequency corresponding to the frequency designated to the person or object and transceiver. Receivers selectively disposed throughout the area of surveillance receive the transmitted output signal from the transceiving means, and transmit a location identification signal which identifies the location within the area of surveillance of the output signal receiver. A console is disposed at a central location within the area of surveillance for receiving the location identification signal and indicating the location of the person or object located.

Claims

1. An electronic tracking and locating system for automatically locating at least one of a select group of individuals or objects disposed in different rooms within a selected area of surveillance, comprising:

means for generating and transmitting an ultrasonic identification signal at one of a plurality of preselected frequencies to the different rooms throughout the selected area of surveillance, the frequency of said signal being unique with respect to the individual or object to be located;

transceiving means, remote from said identification signal generation and transmission means, and carried by each individual or object within the select group, for receiving said information signal, and transmitting an output signal at a pre-selected ultrasonic frequency in response to an identification signal having a frequency corresponding to the frequency designated to the person or object and transceiving means;

a plurality of means, selectively disposed in the separate rooms throughout the area of surveillance, for receiving said transmitted ultrasonic output signal from said transceiving means, and transmitting a location identification signal which identifies the location within the area of surveillance of said output signal receiving means; and

means, disposed at a central location within the area of surveillance, for receiving said location identification signal and indicating the location of the person or object located.

2. The electronic tracking and locating system as recited in claim 1, wherein said identification signal generating and transmission means, comprises, a keyboard having a plurality of manually operated buttons, each representing a selected frequency designated to a particular person or object to be located, means, coupled to said keyboard, for selecting one of a plurality of preselected frequencies;

an oscillator, coupled to said frequency selection means, and at least one signal transducers, coupled to said oscillator, for transmitting said identification signal within said selected area of surveillance.

3. The electronic tracking and locating system as recited in claim 2, wherein said transceiving means comprises, means for receiving signals at only a selected one of said preselected frequencies generated by said identification signal transmitting and generating means, an oscillator, coupled to said selected frequency signal receiving means, for generating a return signal at a preselected frequency upon the reception by said selected frequency signal receiving means of an identification signal having a frequency corresponding to that designated to the transceiving means and person or object to be located, a gate coupled to said oscillator and said receiving means, and a transducer, coupled to said gate for receiving said signal transmitted by said signal generating and transmitting means, and transmitting said return signal generated by said transceiving means oscillator.

4. The electronic tracking and locating system as recited in claim 3, wherein said transceiving means further comprises a time delay, coupled to said selected frequency signal receiving means, and to said transceiving means oscillator, for delaying the generation of said signal generated by said transceiving means oscillator for a predetermined period of time after reception of a signal having a frequency designated to the transceiver and the person or object to be located.

5. The electronic tracking and locating system as recited in claim 3, wherein said frequency selection means comprises a plurality of relay switches, coupled and responsive to said keyboard buttons, and a plurality of capacitors, coupled to said relay switches and said oscillator of said identification signal generating and transmission means, for selectively generating a signal of a predetermined frequency in response to the depression of at least one of said keyboard buttons.

6. The electronic tracking and locating system as recited in claim 1, wherein said transceiving means transmits said output signal at only one preselected frequency, all of said transceiving means disposed within the selected area of surveillance transmitting output signals at said preselected frequency.

7. The electronic tracking and locating system as recited in claim 1, wherein said identification signal generating and transmitting means further comprises means for initiating transmission of said identification signal at a predetermined time and for controlling the duration of the transmission of said identification signal, wherein said transceiving means comprises means for delaying the transmission of said output signal for a predetermined time period after the reception of an identification signal having a frequency corresponding to the frequency designated to said transceiving means, and for controlling the duration of the transmission of said output signal, and wherein said means for receiving said transmitted output signal from said transceiving means further comprises means for delaying the transmission of said location identification signal for a predetermined time period and thereby blocking transmission of said location identification signal during the period of time in which said location identification signal transmission is delayed.

8. The electronic tracking and locating system as recited in claim 1, wherein said means for generating and transmitting said identification signal further comprises a modulator for modulating said preselected frequency generated and transmitted by said means, wherein said transceiving means further comprises a demodulator for detecting the modulating frequency generated by said modulator of said identification signal generating and transmitting means, and a modulator for modulating said output signal transmitted by said transceiving means at a single modulating frequency, and wherein said means for receiving said transmitted output signal from said transceiving means further comprises a demodulator for detecting said single modulating frequency transmitted by said transceiving means modulator.

9. The electronic tracking and locating system as recited in claim 1, wherein said means for generating and transmitting said identification signal further comprises a modulator, for modulating said transmitted identification signal, wherein said transceiving means further comprises a demodulator for detecting said modulated signal transmitted by said signal generating and transmitting means, and a modulator for modulating said output signal transmitted by said transceiving means at one of a plurality of preselected modulating frequencies, said transceiving means each being designated one of said plurality of modulating frequencies, and wherein said means for receiving said transmitted output signal from said transceiving means further comprises a demodulator, for detecting said pluralitY of modulating frequencies transmitted by said transceiving means.

10. The electronic tracking and locating system as recited in claim 3, wherein said means for receiving said location identification signal includes a plurality of digital readout tubes, coupled to said means for receiving said transmitted output signal from said transceiving means.