IFF system cooperating with further position finding device
First Claim
1. IFF apparatus comprising:
- first transmission means operable to transmit first signals as interrogation signals with a broad radiation characteristic;
second transmission means operable to transmit second signals with a narrow radiation lobe directed within the broad radiation lobe;
first receiving means for receiving said first signals;
second receiving means for receiving said second signals;
control means connected to said first and second receiving means and responsive to the occurrence of a second signal within a predetermined time section of a first signal to produce a trigger;
third transmission means connected to said control means and responsive to a trigger to transmit a third signal as an answer signal; and
third receiving means for receiving third signals, including evaluation means for evaluating the third signals.
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Accused Products
Abstract
An IFF system comprises an interrogation device having an antenna arrangement operating in the HF or microwave range with a relatively broad radiation characteristic for radiation of coded interrogation pulses and for receiving answer signals. The IFF system cooperates with a position finding device whose transmission pulses are radiated by way of a relatively narrow radiation lobe and wherein the answer signals are triggered in the answering device in response to the arrival of transmission pulses of the position finding device. A pulse laser operating in the optical range and having a very narrow radiation lobe at the transmission radiator is used as the position finding device and an answer signal is only triggered in the answering device with the aid of a control circuit when the transmission pulse of the laser transmitter arrives in a certain section during the interrogation pulse produced by the interrogation transmitter, the duration of the interrogation pulses being essentially greater than the duration of the transmission pulses.
13 Citations
7 Claims
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1. IFF apparatus comprising:
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first transmission means operable to transmit first signals as interrogation signals with a broad radiation characteristic; second transmission means operable to transmit second signals with a narrow radiation lobe directed within the broad radiation lobe; first receiving means for receiving said first signals; second receiving means for receiving said second signals; control means connected to said first and second receiving means and responsive to the occurrence of a second signal within a predetermined time section of a first signal to produce a trigger; third transmission means connected to said control means and responsive to a trigger to transmit a third signal as an answer signal; and third receiving means for receiving third signals, including evaluation means for evaluating the third signals. - View Dependent Claims (2, 3, 4)
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5. An IFF system comprising:
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an interrogation station and at least one target including a transponder; a first HF transmitter and an antenna coupled thereto in said interrogation station for transmitting coded interrogation pulses toward the target with a broad radiation lobe; a laser transmitter in said interrogation station for transmitting laser pulses toward the target in a narrow radiation pattern within the broad radiation lobe; transmission control means connected to said first HF transmitter and laser transmitter to effect laser transmission within the duration of the interrogation pulses; a first HF receiver in said transponder for receiving the interrogation pulses; a laser receiver in said transponder for receiving the laser pulses; control means connected to said first HF receiver and to said laser receiver to produce a trigger in response to receipt of a laser pulse within a predetermined time section of the interrogation pulses; a second HF transmitter in said transponder connected to said control means and responsive to the trigger to transmit coded answer pulses; a second HF receiver coupled to said antenna for receiving the coded answer pulses; and decoding and evaluating means connected to said second HF receiver.
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6. A method of identifying a target as a friend or foe at an interrogation station having transmitting and receiving equipment and the target including a transponder, comprising the steps of:
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transmitting a HF interrogation signal in a wide radiation lobe toward the target, and at the same time transmitting a laser pulse toward the target in a narrow pattern within the wide pattern; receiving the HF interrogation signal and the laser pulse at the target target transponder; comparing the time position of the received laser pulse with respect to the received interrogation signal and generating a trigger when the received laser pulse coincides with a predetermined time section of a received interrogation signal; transmitting a HF answer signal with the transponder in response to generation of the trigger; and receiving and evaluating the HF answer signal at the interrogation station.
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7. A method of identifying a friend or foe target, comprising the steps of:
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at an interrogation station, scanning a target area with a wide radiation lobe microwave transmission of interrogation signals while simultaneously scanning the target area with laser pulses in a narrow radiation lobe; receiving the microwave and laser signals at a target; transmitting microwave answer signals from the target in response to receipt of a laser pulse during a certain time section of a microwave interrogation signal; and receiving and evaluating the microwave answer signals at the interrogation station.
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Specification