Object location/identification system

• US 3,898,619 A
• Filed: 06/29/1973
• Issued: 08/05/1975
• Est. Priority Date: 06/29/1973
• Status: Expired due to Term

• Current Assignee: Union Switch & Signal, Inc. (Hitachi, Ltd.)
• Original Assignee: Bruce W. Carsten, Stanley Knotek
• Inventors: Carsten, Bruce W., Knotek, Stanley
• Primary Examiner(s): Yusko, Donald J.
• Application Number:
  US05/374,914
• Time in Patent Office: 767 Days
• Field of Search: 340/152T,152R,171PF,151,258C 343/6.5SS
• US Class Current: 340/10.42
• CPC Class Codes: G08G 1/017 identifying vehicles G08G1/015, G08G1/054 take precedence

Abstract

A system for identifying a particular object with respect to other such objects, or locating a particular object within a specified area of use. A plurality of responder units, in combination with at least one interrogator-receiver unit, are provided in the system. Each responder unit may be actuated by predetermined signals from the interrogator-receiver unit, or by means of its own separate power supply. The responder unit generates and transfers back to the interrogator-receiver a coded signal which is unique to that particular responder and which thus identifies the location of that responder in the system. The unique coded signal data transferred to the interrogator-receiver will, after detection by the receiver, be in turn transmitted to a central data unit for display purposes or further information processing. The individual responder units may be placed within moving objects such as vehicles, and the interrogator location remaining fixed, or in another system configuration, the responder units may be positioned at strategic locations within a specified area, while individual interrogator-receiver units are placed on the moving objects, such as vehicles. Signal transfer between the individual responders and the interrogator receivers is accomplished by means of inductive coupling through use of resonant circuits.

Claims

1. An object location/identification system comprising a transceiver means and at least one unpowered responder means and further comprising:

means in said transceiver means generating a continuous alternating current interrogating clock signal having a predetermined frequency;

first means in said transceiver means and said responder means for inductively coupling said interrogating clock signal from said transceiver means to said responder means;

resonant circuit means in said responder means for detecting said interrogating clock signal;

circuit means in said responder means generating a DC power signal from said detected interrogating clock signal;

counter means in said responder means responsive to said detected interrogating clock signal and powered by said DC power signal for generating output pulses at predetermined counts of said interrogating clock signal;

means in said responder means responsive to said output pulses for generating a pulse series signal representing code data uniquely identified with said responder means, said pulse series signal having a repetition rate derived from said interrogating clock signal;

means in said responder means powered by said DC power signal for generating a data carrier signal having a frequency substantially greater than said predetermined frequency of said interrogating clock signal;

means in said responder means for controlling said data carrier signal generating means with said pulse series signal to produce an intermittent data signal, said code data being represented in binary format, the presence of said data carrier signal representing one binary state and the absence of said data carrier signal representing the other binary state; and

second means in said responder means and in said transceiver means inductively coupling said intermittent data signal from said responder means to said transceiver means.

2. The system of claim 1, wherein said first inductive coupling means includes in the transceiver a first resonant circuit, said first resonant circuit further including a first transmitting coil, said first inductive coupling means further including in the responder a second resonant circuit, comprising a first power coil and at least one tuning capacitor.

3. The system of claim 2, wherein said second inductive coupling means includes in the responder a third resonant circuit, said third resonant circuit further including a second transmitting coil.

4. The system of claim 3, wherein said first power coil and said second transmitting coil are positioned in said responder means to lie in spaced, substantially parallel planes, and further sufficiently overlap each other to result in substantially zero flux coupling between said first power coil and said second transmitting coil in operation.

5. The system of claim 1, wherein said second inductive coupling means includes in the transceiver means for receiving said intermittent data signal coupled from the responder, said intermittent data signal having positive and negative peaks, and wherein the transceiver further includes means for detecting said intermittent data signal, said detecting means including means for detecting said positive and negative peaks of said intermittent data signal, and means for determining an average value therebetween, and further including means for comparing said average value with the instantaneous magnitude of said detected intermittent data signal, said comparing means generating an output signal having one magnitude when said average value is greater than said instantaneous magnitude of said intermittent data signal, and having a second magnitude when said average value is less than said instantaneous magnitude of said detected intermittent data signal, said output signal thereby providing a reliable indication of said code data uniquely identified with the responder means.

6. The system of claim 5, wherein said detecting means further includes filter means tuned to pass said data carrier signal frequency, an RF peak detector responsive to said filter means, said RF peak detector producing a pulse output, an inverting amplifier, means applying said pulse output to said inverting amplifier, and positive and negative peak detectors, said inverting amplifier having an output which in turn is applied simultaneously to said positiive and negative peak detectors, said average value determining means including first and second resistance means and a storage capacitor, said first and second resistance means being connected, respectively, between said positive and negative peak detectors and one side of said storage capacitor, the voltage appearing on said storage capacitor being said average value of said intermittent data signal, and means connecting one side of said capacitor to one input of said comparing means.

7. The system of claim 1 wherein said means for generating a pulse series signal includes a diode matrix and gating means, said diode matrix having a series of outputs and responsive to a first group of predetermined outputs of said counter, and wherein said gating means is responsive to said series of outputs of said diode matrix and other outputs of said counter for producing said code signal.

8. The system of claim 7, wherein said diode matrix includes a plurality of input lines and a plurality of diodes connecting selected input lines to selected outputs of said diode matrix, said first group of selected outputs of said counter means being coupled to successive ones of said diode matrix input lines.

9. The system of claim 1, wherein said transceiver means and said unpowered responder means are, in operation, moving relative to one another and wherein signal coupling therebetween occurs whenever said transceiver means and said unpowered responder means are sufficiently close in physical proximity to one another to permit inductive coupling therebetween.

10. The system of claim 9, wherein said transceiver is stationary and said responder is moving.

11. The system of claim 10, wherein said transceiver is moving and said responder is stationary.

12. The system of claim 1, wherein said coded data includes synchronizing information bits and responder identification bits, and wherein said apparatus includes means for altering the number of responder identification bits without altering the total number of coded data bits.