US6188481B1
Expired / Lapsed
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Spatial interferometry
Assignee: BAE Systems Electronics Ltd
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Filing: 1997-07-03
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Granted: 2001-02-13
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Expires: 2017-07-03
Abstract
Abstract An interferometer comprises a non-uniform beam splitter ( 34 ) which splits an incoming beam ( 30 ) of energy into two beams ( 36, 38 ). The two beams ( 36, 38 ) are taken from parts of the incoming beam ( 30 ) which overlap. The two beams ( 36, 38 ) are fed spacially separated energy feeds ( 44, 46 ) and then fed to a comparator to produce sum and difference channels ( 54, 58 ). The sum and difference channels ( 54, 58 ) are guided to a means for detecting a difference in phase ( 60 ) between the sum and difference channels ( 54, 58 ).
Inventors
- 👤 Balbir Kumar
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 10:14
CPC Classifications
G; G01; G01S; G01S3/00; G01S3/78; G01S3/782; G01S3/02; G01S3/14; G01S3/28; G01S3/32; G01S13/00; G01S13/02; G01S13/06; G01S13/42; G01S13/44; G01S13/4409; G01S13/4454; G01S3/46; G01S3/48
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
99 words
An interferometer comprising: beam splitter means having an aperture, the beam splitter means splitting an incoming beam of energy incident on the aperture into at least a first beam and a second beam, the first and second beams originating substantially from separate regions of the aperture; first and second energy feeds for receiving said first and second beams, the beam splitter means and the energy feeds being separated by free space; and means for detecting a phase difference between the first and second beams; wherein the regions of the aperture from which the first and second beams originate overlap.
Claim 2
Dependent Claim
99 words
An interferometer comprising: beam splitter means having an aperture, the beam splitter means splitting an incoming beam of energy incident on the aperture into at least a first beam and a second beam, the first and second beams originating substantially from separate regions of the aperture; first and second energy feeds for receiving said first and second beams, the beam splitter means and the energy feeds being separated by free space; and means for detecting a phase difference between the first and second beams; wherein the regions of the aperture from which the first and second beams originate overlap.
Claim 3
Dependent Claim
22 words
An interferometer according to claim 1 wherein the first and second beams are fed to the energy feeds which are spatially separated.
Claim 4
Dependent Claim
27 words
An interferometer according to claim 1 , wherein the beam splitter means has a non-uniform splitting ratio from one side of its aperture to the other side.
Claim 5
Dependent Claim
18 words
An interferometer according to claim 1 wherein the reflectivity of the beam splitter means changes across its surface.
Claim 6
Dependent Claim
19 words
An interferometer according to claim 1 wherein the splitting ratio varies in more than one direction across the surface.
Claim 7
Dependent Claim
22 words
An interferometer according to any preceding claim wherein the first and second beams are obtained from opposite sides of the incoming beam.
Claim 8
Dependent Claim
36 words
An interferometer according to claim 1 wherein the first and second beams are fed into respective pairs of adjacent energy feeds disposed such that there is no null-point at the junction of the adjacent energy feeds.
Claim 9
Dependent Claim
23 words
An interferometer according to claim 7 wherein it comprises a single beam splitter which splits the beam only into first and second beams.
Claim 10
Dependent Claim
19 words
An interferometer according to claim 1 wherein the incoming beam of energy is split into more than two beams.
Claim 11
Dependent Claim
15 words
An interferometer according to claim 1 wherein the incoming beam is split into four beams.
Claim 12
Dependent Claim
20 words
An interferometer according to claim 1 or claim 10 wherein the beam splitter means comprises more than one beam splitter.
Claim 13
Dependent Claim
27 words
An interferometer according to claim 11 wherein there are three beam splitters each beam splitter having a changing splitting ratio across its surface in one direction only.
Claim 14
Dependent Claim
24 words
An interferometer according to claim 1 wherein the beam splitter means acts directly on the incoming beam to separate the first and second beams.
Claim 15
Dependent Claim
45 words
An interferometer according to claim 1 wherein the beam splitter means comprises an optical device which does not split the incoming beam but changes a characteristic across part of the incoming beam to produce a modified beam and a splitter which splits the modified beam.
Claim 16
Dependent Claim
25 words
An interferometer according to claim 1 wherein the first and second beams are guided to the means for detecting a difference by a waveguide structure.
Claim 17
Dependent Claim
25 words
An interferometer according to claim 1 wherein the first and second beams are guided to the means for directing a phase difference through free space.
Claim 18
Dependent Claim
12 words
A tracking system comprising an interferometer as claimed in claim 1 .
Claim 19
Dependent Claim
20 words
A tracking system according to claim 17 , wherein an incoming signal to said tracking system comprises a radar signal.
Claim 20
Independent Claim
89 words
A method of interferometry on an incoming beam of energy comprising the steps of: directing the incoming beam of energy onto an aperture splitting it into at least a first beam and a second beam, the first and second beams being primarily obtained from separate parts of the aperture, propagating the first and second beams through free space to respective energy feeds, and detecting a phase difference between the first and second beams, wherein the parts of the incoming beam from which the first and second beams originate overlap.
Claim 21
Independent Claim
89 words
A method of interferometry on an incoming beam of energy comprising the steps of: directing the incoming beam of energy onto an aperture splitting it into at least a first beam and a second beam, the first and second beams being primarily obtained from separate parts of the aperture, propagating the first and second beams through free space to respective energy feeds, and detecting a phase difference between the first and second beams, wherein the parts of the incoming beam from which the first and second beams originate overlap.
Claim 22
Dependent Claim
50 words
An interferometer according to claim 1 , said beam splitter comprising a single beam splitter that produces the first and second beams, and said first and second energy feeds comprising two pairs of adjacent energy feeds, each of the beams being split by one of the pair of energy feeds.
Claim 23
Dependent Claim
32 words
An interferometer according to claim 1 , wherein each of said first and second beams, split from the incoming beam by said beam splitter means, is fed to a single energy feed.
References Cited (Backward Citations)
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