Secondary surveillance radar
First Claim
Patent Images
1. A secondary surveillance radar including:
- a transmitter to transmit radar signals that interrogate transponders on remote targets;
a receiver to receive returns from the interrogated transponders on the targets; and
a controllable power source to produce r.f. signals for the transmitter, comprising circuitry to produce first and second r.f. signals having a predetermined phase relationship;
a phase setter that sets the phase relationship between first and second signals selectively;
first and second power amplifiers to amplify the first and second signals respectively; and
a power combiner to combine the first and second signals amplified by the amplifiers whereby to provide an amplified r.f. output signal of a power dependent upon the phase relationship set by the phase setter.
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Abstract
A secondary surveillance radar e.g. a Mode-S radar, has a controllable power source in which first and second in-phase r.f. signals are derived from a source (6) by a power splitter (11), and a phase shifter (32) adjusts selectively the relative phase of the signals, so that after amplification by main amplifiers (21, 22) and combination by power comber (23), the resultant power level can be controlled by the phase shift produced by the phase shifter (32).
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Citations
22 Claims
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1. A secondary surveillance radar including:
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a transmitter to transmit radar signals that interrogate transponders on remote targets; a receiver to receive returns from the interrogated transponders on the targets; and a controllable power source to produce r.f. signals for the transmitter, comprising circuitry to produce first and second r.f. signals having a predetermined phase relationship;
a phase setter that sets the phase relationship between first and second signals selectively;
first and second power amplifiers to amplify the first and second signals respectively; and
a power combiner to combine the first and second signals amplified by the amplifiers whereby to provide an amplified r.f. output signal of a power dependent upon the phase relationship set by the phase setter. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A Mode-S SSR comprising:
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an antenna configuration; a transmitter coupled to the antenna configuration to transmit radar signals that interrogate transponders on remote targets; a receiver coupled to the antenna configuration to receive returns from the interrogated transponders on the targets; and a controllable power source to produce r.f. signals for the transmitter, comprising circuitry to produce first and second r.f. signals;
a phase setter that sets the phase relationship between the first and second signals selectively;
first and second power amplifiers to amplify the first and second signals respectively; and
a power combiner to combine the first and second signals amplified by the power amplifiers whereby to provide an amplified r.f. output signal of a power dependent upon the phase relationship set by the phase setter.
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18. A method of operating a secondary surveillance radar including:
transmitting radar signals so as to interrogate transponders on remote targets;
receiving returns from the interrogated transponders on the targets; and
controlling the power of the transmitted signals, comprising producing first and second r.f. signals;
selectively setting the phase relationship between the first and second signals;
amplify the first and second signal respectively;
combining the first and second amplified signals whereby to provide an amplified r.f output signal for transmission.- View Dependent Claims (19, 20, 21)
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22. A method of operating a Mode-S SSR including:
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transmitting radar signals from an antenna configuration so as to interrogate transponders on remote targets; receiving returns from the interrogated transponders on the targets at the antenna configuration; and controlling the power of the transmitted signals, by producing first and second r.f. signals;
selectively setting the phase relationship between the first and second signals amplifying the first and second signals respectively;
combining the first and second amplified signals whereby to provide an amplified r.f. output signal of a power dependent upon the set phase relationship; and
feeding the out signal to the antenna configuration for transmission.
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Specification