Method of and system for classifying emergency locating transmitters and emergency positions indicating radio beacons
AssigneeThe United States of America as represented by the Administrator of the National Aeronautics and Space Administration
InventorPaul E. Wren
Life of this patent
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Abstract
During a distress call, a distress location transmitter 10 generates a high frequency carrier signal 40 that is modulated by a predetermined distress waveform characteristic 29. The classification of user associated with the distress call is identified by periodically interrupting modulation 42; user classification is determined by the repetition rate of the interruptions, the interruption periods, or both.
Claims10
A distress location transmitter, comprising:
- oscillator means for generating a carrier signal to be supplied to an antenna during a distress call;
- means for modulating said carrier signal with a distress characteristic waveform;
- and
- means for periodically disabling said modulating means at a predetermined rate corresponding to one of a plurality of classes of user for said distress location transmitter in providing a period of unmodulated carrier to identify said user class associated with said distress call.
A distress location transmitter, comprising:
- oscillator means for generating a carrier signal to be supplied to an antenna during a distress call;
- means for modulating said carrier signal with a distress waveform;
- means for enabling an output of said modulating means for a first period of time
- and for disabling said output for a second period of time;
- and
- means for controlling the time periods of said means for enabling and disabling in accordance with one of a plurality of classes of user for said distress location transmitter in providing a period of unmodulated carrier to identify said user class associated with said distress call.
A method of identifying a user class associated with a distress call comprising a carrier signal transmitted at a predetermined frequency and modulated by a distress characteristic waveform, the method comprising the step of periodically interrupting modulation of said carrier signal at a predetermined repetition rate corresponding to one of a plurality of classes of user for said distress call in providing a period of unmodulated carrier to identify the user class.
A method of identifying a user class associated with a distress call comprising a carrier signal transmitted at a predetermined frequency and modulated by a distress characteristic waveform, the method comprising the step of periodically interrupting modulation of said carrier signal for a predetermined time duration corresponding to one of a plurality of classes of user for said distress call in providing a period of unmodulated carrier to identify the user class.
Dependencies are inferred from the claim text.