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US 4,788,547 AGranted
Static-split tracking radar systems
AssigneeThe Marconi Company Limited
InventorsMichael A. Jones, John R. G. Woods
Life of this patent
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Abstract
A static-split tracking radar system with substantially improved performance. The system includes parallel signal processing channels for processing sum and difference signals from a target-seeking aerial array, to produce target tracking signals. Novel means are provided for trimming relative phase and gain of these channels to achieve substantially perfect matching, which gives a receiver stability sufficient for homing head use in a guided missile system. The system also includes a receiver for acquiring a reference frequency signal, the receiver having novel bandwidth adaptation and doppler tracking facilities. Other novel features provide improved clutter rejection and jamming immunity.
Claims16
A static-split tracking radar system comprising
- (A) an aerial
- (i) having more than two outputs,
- (B) a first combining circuit for combining signals from said aerial outputs to produce at least two receiver input signals,
- (i) the relative phases and amplitudes of which contain information characterizing the orientation of a target relative to the aerial,
- (C) a receiver having two channels to which said receiver input signals are respectively applied,
- (D) a second combining circuit for combining output signals from the channels of said receiver to produce a feedback signal,
- (E) said first and second combining circuits being such that said feedback signal characterizes the degree of mismatch between said channels,
- (F) the system also comprising at least one trimming circuit which is connected in one of said channels and which is responsive to said feedback signal for automatically correcting mismatch between said channels,
- (G) means to produce a modulating waveform,
- (H) said first combining circuit including means to modulate said receiver input signals in synchronism with the modulating waveform to cause said receiver input signals to vary periodically in amplitude and phase relative to each other in such a manner that the average value of their difference over one period of said modulating waveform is zero, and
- (I) differencing and averaging means coupled to receive the output signals from said receiver channels and to produce said feedback signal by averaging the difference of the output signals from said receiver channels over at least one period of said modulating waveform, whereby when said channels are equally matched, said feedback signal is zero, and when said channels are mismatched said feedback signal is non-zero.
8 more elements
A static-split tracking radar system comprising
- (A) an aerial
- (i) having more than two outputs,
- (B) a first combining circuit for combining signals from said aerial outputs to produce at least two receiver input signals,
- (i) the relative phases and amplitudes of which contain information characterizing the orientation of a target relative to the aerial,
- (C) a receiver having two channels to which said receiver input signals are respectively applied,
- (D) a second combining circuit for combining outupt signals from the channels of said receiver to produce a feedback signal,
- (E) said first and second combining circuits being such that said feedback signal characterizes the degree of mismatch between said channels,
- (F) the system also comprising at least one trimming circuit which is connected in one of said channels and which is responsive to said feedback signal for automatically correcting mismatch between said channels, and
- (G) means to produce a modulating waveform,
- (H) said first combining circuit including means to modulate said receiver input signals in synchronism with the modulating waveform to cause said receiver input signals to vary periodically in amplitude and phase relative to each other in such a manner that the average value of their difference over one period of said modulating waveform is zero.
7 more elements
A static-split tracking radar system comprising
- (A) an aerial
- (i) having more than two outputs,
- (B) a first combining circuit for combining signals from said aerial outputs to produce at least two receiver input signals,
- (i) the relative phases and amplitudes of which contain information characterizing the orientation of a target relative to the aerial,
- (C) a receiver having two channels to which said receiver input signals are respectively applied,
- (D) a second combining circuit for combining outupt signals from the channels of said receiver to produce a feedback signal,
- (E) said first and second combining circuits being such that said feedback signal characterizes the degree of mismatch between said channels,
- (F) the system also comprising at least one trimming circuit which is connected in one of said channels and which is responsive to said feedback signal for automatically correcting mismatch between said channels,
- (G) a phase lock loop connected in the second combining circuit, and
- (H) the output signal of said phase lock loop providing a signal of reduced bandwidth.
7 more elements
A static-split tracking radar system comprising
- (A) an aerial
- (i) having more than two outputs,
- (B) a first combining circuit for combining signals from said aerial outputs to produce at least two receiver input signals,
- (i) the relative phases and amplitudes of which contain information characterizing the orientation of a target relative to the aerial,
- (C) a receiver having two channels to which said receiver input signals are respectively applied,
- (D) a second combining circuit for combining output signals from the channels of said receiver to produce a feedback signal,
- (E) said first and second combining circuits being such that said feedback signal characterizes the degree of mismatch between said channels,
- (F) the system also comprising at least one trimming circuit which is connected in one of said channels and which is responsive to said feedback signal for automatically correcting mismatch between said channels,
- (G) each said receiver channel comprising
- (i) a mixer,
- (ii) an intermediate frequency amplifier and
- (iii) a filter connected in series, and
- (H) means for cross coupling a signal containing a percentage of the output of the intermediate frequency amplifier of each channel into the output of the intermediate frequency amplifier of the other respective channel.
10 more elements
A static-split tracking radar system comprising
- (A) an aerial
- (i) having more than two outputs,
- (B) a first combining circuit for combining signals from said aerial outputs to produce at least two receiver input signals,
- (i) the relative phases and amplitudes of which contain information characterizing the orientation of a target relative to the aerial,
- (C) a receiver having two channels to which said receiver input signals are respectively applied,
- (D) a second combining circuit for combining output signals from the channels of said receiver to produce a feedback signal,
- (E) said first and second combining circuits being such that said feedback signal characterizes the degree of mismatch between said channels,
- (F) the system also comprising at least one trimming circuit which is connected in one of said channels and which is responsive to said feedback signal for automatically correcting mismatch between said channels,
- (G) a second aerial,
- (H) a local oscillator the output frequency of which is mixed with one of said receiver channel inputs, and
- (I) means for controlling the frequency of said local oscillator both in response to a signal received at said second aerial and in response to a signal obtained from an output signal of said second combining circuit.
8 more elements
A tracking radar system for use in a moving body, comprising a first aerial;
- a superheterodyne receiver for processing signals from the first aerial, the receiver including a local oscillator;
- a second aerial for receiving a reference signal;
- a phase-locked loop for locking the frequency of said local oscillator in a fixed relationship to that of the reference signal;
- and means to automatically adjust the bandwidth of the phase-locked loop according to the received strength of the reference signal, so that when the received reference signal is strong, the bandwidth is relatively wide, and when the received reference signal is weak, the bandwidth is relatively narrow.
1 more element
Dependencies are inferred from the claim text.