摘要 |
A secure identification system for identifying a potential target in a battlefield environment as being either a friend or a foe is disclosed. An interrogator produces two interrogation pulses, such as laser flashes, aimed at the target and separated from each other by a randomly determined period of time. The target detects the two interrogation pulses, measures elapsed time between the two pulses, and prepares a reply signal for transmission which is controlled by the elapsed time. Frequency, pulse width, and transmission delay parameters are each controlled in a substantially random, but predetermined manner in response to the elapsed time. The interrogator has a receiver and qualifier which receive reply signals and define expected values for the controlled parameters. An indication is provided concerning whether the target represents a friend or a foe based on received reply signals at the interrogator.
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