US3790941A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Antenna tracking systems
Assignee: UK Secretary of State for Defence
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Filing: 1972-03-27
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Granted: 1974-02-05
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Expires: 1992-03-27
Abstract
Abstract Apparatus for controlling a steerable antenna to track a distant radio source, according to the relative phase and amplitude of TMO1 mode signals and TE11 mode signals developed in a circular waveguide which receives the radio signals collected by the antenna. The apparatus comprises a TMO1 mode coupler and a modulator arranged to apply a cyclic modulation to signals derived from the TMO1 mode, a second coupler connected to combine the modulated signals with signals derived from the TE11 mode signals to form an amplitude-modulated resultant signal, and detector means for deriving tracking control signals from the amplitude modulation on the resultant signal. The modulation may be a sawtooth or a sinusoidal waveform and the detector means may comprise a phase sensitive detector for comparing the amplitude modulation with the modulation control waveform. Alternatively the modulation may be a four-step staircase or a staircase with the steps transposed; then the detector means may comprise four detectors arranged to operate in synchronism with the steps of the staircase and two differential amplifiers. The second coupler may be connected to the circular waveguide by a polarizer. The modulator may be a ferrite phase shifter but a diode balanced modulator may be used if the modulation is sinusoidal.
Inventors
- 👤 M Chivers
- 👤 T Dawson
- 👤 P Masterman
- 👤 M Weston
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 05:48
CPC Classifications
H; H01; H01Q; H01Q25/00; H01Q25/04
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
324 words
Apparatus for controlling a steerable antenna to collect electromagnetic waves from a distant source including: circular waveguide means for receiving electromagnetic wave signals collected by the antenna for supporting circularly polarized TE11 mode signals in response to circularly polarized electromagnetic wave signals received from a distant source near to or on a predetermined steerable axis of the antenna and for supporting TM01 mode signals in response to electromagnetic wave signals received from a distant source near to but not on the predetermined axis, a TM01 mode signal coupler means connected to the circular waveguide means and responsive to TM01 mode signals developed in the circular waveguide means, a modulator connected to the output of the TM01 mode coupler means, control means connected to the modulator for applying a cyclic modulation control waveform to the modulator, a polarizer connected to the circular waveguide means and constructed to transform the said circularly polarized TE11 mode signals into TE11 mode signals linearly polarized in a given plane, a square section waveguide connected to the polarizer and capable of propagating the said TE11 mode signals linearly polarized in the said given plane, a second coupler means connected to the modulator and to the square section waveguide for feeding the output signals from the modulator into the said square section waveguide so that they will combine with the said TE11 mode signals linearly polarized in the said given plane and will thereby form an amplitude modulated resultant signal within the square section waveguide, receiver apparatus connected to the square section waveguide and responsive to signals linearly polarized in the said given plane within the said square section waveguide, and detector means connected to the said receiver apparatus for deriving tracking control signals from the amplitude mOdulation on the said resultant signal to indicate parameters of any misalignment between the predetermined axis of the antenna and the mean direction of incidence of the electromagnetic wave signals from the distant source.
Claim 2
Dependent Claim
324 words
Apparatus for controlling a steerable antenna to collect electromagnetic waves from a distant source including: circular waveguide means for receiving electromagnetic wave signals collected by the antenna for supporting circularly polarized TE11 mode signals in response to circularly polarized electromagnetic wave signals received from a distant source near to or on a predetermined steerable axis of the antenna and for supporting TM01 mode signals in response to electromagnetic wave signals received from a distant source near to but not on the predetermined axis, a TM01 mode signal coupler means connected to the circular waveguide means and responsive to TM01 mode signals developed in the circular waveguide means, a modulator connected to the output of the TM01 mode coupler means, control means connected to the modulator for applying a cyclic modulation control waveform to the modulator, a polarizer connected to the circular waveguide means and constructed to transform the said circularly polarized TE11 mode signals into TE11 mode signals linearly polarized in a given plane, a square section waveguide connected to the polarizer and capable of propagating the said TE11 mode signals linearly polarized in the said given plane, a second coupler means connected to the modulator and to the square section waveguide for feeding the output signals from the modulator into the said square section waveguide so that they will combine with the said TE11 mode signals linearly polarized in the said given plane and will thereby form an amplitude modulated resultant signal within the square section waveguide, receiver apparatus connected to the square section waveguide and responsive to signals linearly polarized in the said given plane within the said square section waveguide, and detector means connected to the said receiver apparatus for deriving tracking control signals from the amplitude mOdulation on the said resultant signal to indicate parameters of any misalignment between the predetermined axis of the antenna and the mean direction of incidence of the electromagnetic wave signals from the distant source.
Claim 3
Dependent Claim
44 words
Apparatus as claimed in claim 1 having a diplexer means connecting the said square section waveguide to the said receiver apparatus, and transmitter means for transmitting signals through the diplexer means, the square section waveguide, the polarizer and the circular waveguide to the antenna.
Claim 4
Dependent Claim
41 words
Apparatus as claimed in claim 1 and wherein the control means comprises a linear sawtooth generator and the modulator is an electrically controllable phase modulator constructed to advance the phase of the TM01 mode signal in response to the control waveform.
Claim 5
Dependent Claim
47 words
Apparatus as claimed in claim 3 and wherein the detector means comprises a phase sensitive detector connected to compare the amplitude modulation on the said resultant signal with the modulation control waveform and to provide signals indicating the amplitude and relative phase of the said amplitude modulation.
Claim 6
Dependent Claim
16 words
Apparatus as claimed in claim 4 and wherein the phase modulator is a ferrite phase shifter.
Claim 7
Dependent Claim
56 words
Apparatus as claimed in claim 1 and wherein the control means comprises means for generating a four step staircase waveform and the modulator is an electrically controllable phase modulator constructed to advance the phase of the TM01 mode signal through 90*, with respect to the TE11 mode signal, at each step in the said staircase waveform.
Claim 8
Dependent Claim
56 words
Apparatus as claimed in claim 6 and wherein the detector means comprises four detectors connected to operate sequentially and in synchronism with the steps in the modulation control waveform, and two differencing amplifiers connected to the said detectors to derive misalignment indicating signals from the difference between the outputs of different pairs of the said detectors.
Claim 9
Dependent Claim
46 words
Apparatus as claimed in claim 1 and wherein the control means comprises a sine wave generator and the modulator comprises a diode balanced modulator constructed to change the frequency of the TM01 mode signal cyclically in response to the output of the said sine wave generator.
References Cited (Backward Citations)
US3530471A
Cited
US3665481A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-02-04 | 1977-08-06 | 1978-02-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-02-04 | 1981-08-06 | 1982-02-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-02-04 | 1985-08-06 | 1986-02-05 | $7700.00 | Window Closed / Lapsed |