IFF-SYSTEM
First Claim
1. An electronic identification system for determining whether a target is friend or foe comprising:
- a. a first radar means to be carried in an aircraft capable of transmitting to an interrogation center a coded signal representing the identification of the aircraft, and second radar means located at the interrogation center for analyzing this coded signal, b. low frequency pulse generating means in each of said first and second radar means, c. identical digital counter means, each connected to one of said pulse generating means, d. means for initially synchronizing the pulse generating means and digital counter means in said second radar means with the pulse generating means and digital counter means in said first radar means, such that the pulse generating means in said second radar means will not differ from the pulse generating means in the station to be identified by more than one-tenth of a cycle after an elapsed time of 100,000 seconds and the digital counter means in each of said first and second radar means will indicate the same number, e. code computers, each connected to one of said digital counter means, the number from said digital counter means in each of said first and second radar means being fed to respective code computers each of which perform a sequence of identical mathematical operations and have identical outputs which are a sequence of random code numbers, the output of the digital counter means and the code computers changing at a desired rate, f. a code generating means connected to the code computer in said first radar means, the output of the code computer in said first radar means being converted into a pulse code by said code generating means, and means for transmitting said pulse code to said second radar means, g. means in said second radar means for receiving the pulse code transmitted from said first radar means, h. decoder means in said second radar means for restoring the received pulse code into its original code numbers and means for comparing these code numbers with the code number from the output of the code computer in the second radar means, whereby when both code nUmbers are equal aircraft carrying said first radar means is identified as friendly.
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Abstract
6. An electronic identification system for determing whether a target is friend or foe comprising: A FIRST RADAR MEANS TO BE CARRIED IN AN AIRCRAFT CAPABLE OF TRANSMITTING TO AN INTERROGATION CENTER A CODED SIGNAL REPRESENTING THE IDENTIFICATION OF THE AIRCRAFT, AND SECOND RADAR MEANS LOCATED AT THE INTERROGATION CENTER FOR ANALYZING THIS CODED SIGNAL, B. PULSE GENERATING MEANS IN EACH OF SAID FIRST AND SECOND RADAR MEANS, C. IDENTICAL DIGITAL COUNTER MEANS, EACH CONNECTED TO ONE OF SAID PULSE GENERATING MEANS, D. MEANS FOR INITIALLY SYNCHRONIZING THE PULSE GENERATING MEANS AND DIGITAL COUNTER MEANS IN SAID SECOND RADAR MEANS WITH THE PULSE GENERATING MEANS AND DIGITAL COUNTER MEANS IN SAID FIRST RADAR MEANS, SUCH THAT THE PULSE GENERATING MEANS IN SAID SECOND RADAR MEANS WILL NOT DIFFER SUBSTANTIALLY FROM THE PULSE GENERATING MEANS IN SAID FIRST RADAR MEANS AND THE DIGITAL COUNTER MEANS IN EACH OF SAID FIRST AND SECOND RADAR MEANS WILL INDICATE THE SAME NUMBER, E. CODE COMPUTERS, EACH CONNECTED TO ONE OF SAID DIGITAL COUNTER MEANS, THE NUMBER FROM SAID DIGITAL COUNTER MEANS IN EACH OF SAID FIRST AND SECOND RADAR MEANS BEING FED TO RESPECTIVE CODE COMPUTERS EACH OF WHICH PERFORM A SEQUENCE OF IDENTICAL MATHEMATICAL OPERATIONS AND HAVE IDENTICAL OUTPUTS WHICH ARE A SEQUENCE OF RANDOM CODE NUMBERS, THE OUTPUT OF THE DIGITAL COUNTER MEANS AND THE CODE COMPUTERS CHANGING AT A DESIRED RATE, F. ADDER MEANS AND CODE GENERATING MEANS CONNECTED TO THE CODE COMPUTER IN THE FIRST RADAR MEANS, THE OUTPUT OF SAID CODE COMPUTER IN SAID FIRST RADAR MEANS BEING FED TO SAID ADDER MEANS WHERE AN IDENTIFICATION NUMBER IS ADDED THERETO, THE RESULTANT NUMBER BEING CONVERTED INTO A CODE SIGNAL BY SAID CODE GENERATING MEANS, AND MEANS FOR TRANSMITTING SAID CODE SIGNAL TO SAID SECOND RADAR MEANS, G. MEANS IN SAID SECOND RADAR MEANS FOR RECEIVING THE CODE SIGNAL TRANSMITTED FROM SAID FIRST RADAR MEANS, H. DECODER MEANS IN SAID SECOND RADAR MEANS FOR RESTORING THE RECEIVED CODE SIGNAL INTO ITS ORIGINAL RESULTANT NUMBER AND MEANS FOR SUBTRACTING THE OUTPUT OF THE CODE COMPUTER IN THE SECOND RADAR MEANS THEREFROM, WHEREBY AN AIRCRAFT CARRYING SAID FIRST RADAR MEANS WILL BE IDENTIFIED BY ITS IDENTIFICATION NUMBER.
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Citations
7 Claims
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1. An electronic identification system for determining whether a target is friend or foe comprising:
- a. a first radar means to be carried in an aircraft capable of transmitting to an interrogation center a coded signal representing the identification of the aircraft, and second radar means located at the interrogation center for analyzing this coded signal, b. low frequency pulse generating means in each of said first and second radar means, c. identical digital counter means, each connected to one of said pulse generating means, d. means for initially synchronizing the pulse generating means and digital counter means in said second radar means with the pulse generating means and digital counter means in said first radar means, such that the pulse generating means in said second radar means will not differ from the pulse generating means in the station to be identified by more than one-tenth of a cycle after an elapsed time of 100,000 seconds and the digital counter means in each of said first and second radar means will indicate the same number, e. code computers, each connected to one of said digital counter means, the number from said digital counter means in each of said first and second radar means being fed to respective code computers each of which perform a sequence of identical mathematical operations and have identical outputs which are a sequence of random code numbers, the output of the digital counter means and the code computers changing at a desired rate, f. a code generating means connected to the code computer in said first radar means, the output of the code computer in said first radar means being converted into a pulse code by said code generating means, and means for transmitting said pulse code to said second radar means, g. means in said second radar means for receiving the pulse code transmitted from said first radar means, h. decoder means in said second radar means for restoring the received pulse code into its original code numbers and means for comparing these code numbers with the code number from the output of the code computer in the second radar means, whereby when both code nUmbers are equal aircraft carrying said first radar means is identified as friendly.
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2. An electronic identification system for determining whether a target is friend or foe comprising:
- a. a first radar means to be carried in an aircraft capable of transmitting to an interrogation center a coded signal representing the identification of the aircraft, and second radar means located at the interrogation center for analyzing this coded signal, b. pulse generating means in each of said first and second radar means, c. identical digital counter means, each connected to one of said pulse generating means, d. means for initially synchronizing the pulse generating means and digital counter means in said second radar means with the pulse generating means and digital counter means in said first radar means, such that the pulse generating means in said second radar means will not differ substantially from the pulse generating means in said first radar means and the digital counter means in each of said first and second radar means will indicate the same number, e. code computers, each connected to one of said digital counter means, the number from digital counter means in each of said first and second radar means being fed to respective code computers each of which perform a sequence of identical mathemathical operations and have identical outputs which are a sequence of random code numbers, the output of the digital counter means and the code computers changing at a desired rate, f. code generating means connected to the code computer in said first radar means, the output of said code computer in said first radar means;
being converted into a code signal by said code generating means, and means for transmitting said code signal to said second radar means, g. means in said second radar means for receiving the code signal transmitted from said first radar means, h. decoder means in said second radar means for restoring the received code signal into its original code numbers and means for comparing these code numbers with the code number from the output of the code computer in the second radar means, whereby when both code numbers are equal the aircraft carrying said first radar means is identified as friendly.
- a. a first radar means to be carried in an aircraft capable of transmitting to an interrogation center a coded signal representing the identification of the aircraft, and second radar means located at the interrogation center for analyzing this coded signal, b. pulse generating means in each of said first and second radar means, c. identical digital counter means, each connected to one of said pulse generating means, d. means for initially synchronizing the pulse generating means and digital counter means in said second radar means with the pulse generating means and digital counter means in said first radar means, such that the pulse generating means in said second radar means will not differ substantially from the pulse generating means in said first radar means and the digital counter means in each of said first and second radar means will indicate the same number, e. code computers, each connected to one of said digital counter means, the number from digital counter means in each of said first and second radar means being fed to respective code computers each of which perform a sequence of identical mathemathical operations and have identical outputs which are a sequence of random code numbers, the output of the digital counter means and the code computers changing at a desired rate, f. code generating means connected to the code computer in said first radar means, the output of said code computer in said first radar means;
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3. A device as in claim 2 wherein said code signal is a pulse code.
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4. A device as in claim 2 wherein said code signal is a frequency code.
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5. A device as in claim 2 wherein said code signal is a combination of both pulse and frequency code.
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7. An electronic identification system for determining whether a target is friend or foe comprising:
- a. at least one first radar means each to be carried in an aircraft and capable of transmitting to an interrogation center a coded signal representing the identification of the aircraft, and a second radar means located at the interrogation center for analyzing this coded signal, b. low frequency pulse generating means in each of said first and second radar means, c. identical digital counter means, each connected to one of said pulse generating means d. the pulse generating means and digital counter means in the second radar means being synchronized with that in said first radar means, e. code computers, each connected to one of said digital counter means, the number from said digital counter means in each of said first and second radar means being fed to respective code computers each of which perform a sequence of identical mathematical operations and have identical outputs which are a sequence of random code numbers, the output of the digital counter means and the code computers changing at a desired rate, f. code generating means connected to the code computer in said first radar means, the output of said code computer in said first radar means;
being converted into a code signal by said code generating means, and means for transmitting said code signal to said second radar means, g. means in said second radar means for receiving the code signal transmitted from said first radar means, h. decoder means in said second radar means for restoring the received code signal into its original code numbers and means for comparing these code numbers with the code number from the output of the code computer in the second radar means, whereby when both code numbers are equal the aircraft carrying said first radar means is identified as friendly.
- a. at least one first radar means each to be carried in an aircraft and capable of transmitting to an interrogation center a coded signal representing the identification of the aircraft, and a second radar means located at the interrogation center for analyzing this coded signal, b. low frequency pulse generating means in each of said first and second radar means, c. identical digital counter means, each connected to one of said pulse generating means d. the pulse generating means and digital counter means in the second radar means being synchronized with that in said first radar means, e. code computers, each connected to one of said digital counter means, the number from said digital counter means in each of said first and second radar means being fed to respective code computers each of which perform a sequence of identical mathematical operations and have identical outputs which are a sequence of random code numbers, the output of the digital counter means and the code computers changing at a desired rate, f. code generating means connected to the code computer in said first radar means, the output of said code computer in said first radar means;
Specification
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- Resources
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Current AssigneeKlaus J. Hecker
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Original AssigneeKlaus J. Hecker
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InventorsHecker, Klaus J.
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Primary Examiner(s)Hubler, Malcolm F.
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Application NumberUS04/168,287Time in Patent Office4,207 DaysField of Search325/32 343/6.5,6.8,10,11,112.3US Class Current342/45CPC Class CodesG01S 13/78 discriminating between diff...
