Moving platform roll sensor system
First Claim
1. A moving platform roll sensor system, comprising:
- a moving platform, said platform comprising an ellipsometric detector capable of detecting a polarized beam of electromagnetic radiation when said ellipsometric detector is within the line-of-sight of said polarized beam, and of measuring said polarized beam'"'"'s polarization state such that said polarization state indicates the rotational orientation of said moving platform with respect to a predefined coordinate system;
said ellipsometric detector comprising;
a polarizing beamsplitter which receives said detected beam and splits said beam into first and second components having orthogonal circular polarizations, the relative intensities of which vary with the relative polarization vector of said detected beam;
first and second detectors arranged to receive said first and second components having orthogonal circular polarizations, respectively, and to generate respective outputs D1 and D2 that vary with the intensities of their received components; and
circuitry arranged to receive D1 and D2 and to calculate the rotational orientation θ
of said moving platform with respect to said predefined coordinate system, with θ
given by;
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Accused Products
Abstract
A moving platform roll sensor system comprises an ellipsometric detector capable of detecting a polarized beam within the detector'"'"'s line-of-sight, and measuring the beam'"'"'s polarization state, such that the polarization state indicates the rotational orientation of the moving platform with respect to a predefined coordinate system. The ellipsometric detector comprises a venetian blind component through which the polarized beam passes, arranged such that the intensity of the exiting beam varies with its incident angle with respect to the moving platform, a polarizing beamsplitter which splits the exiting beam into components having orthogonal circular polarizations, the relative intensities of which vary with the relative polarization vector of the beam, and first and second detectors which receive the first and second orthogonal circular components and generate respective outputs that vary with the intensities of their received components. The beamsplitter preferably comprises a quarter wave plate and a polarization grating.
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Citations
28 Claims
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1. A moving platform roll sensor system, comprising:
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a moving platform, said platform comprising an ellipsometric detector capable of detecting a polarized beam of electromagnetic radiation when said ellipsometric detector is within the line-of-sight of said polarized beam, and of measuring said polarized beam'"'"'s polarization state such that said polarization state indicates the rotational orientation of said moving platform with respect to a predefined coordinate system; said ellipsometric detector comprising; a polarizing beamsplitter which receives said detected beam and splits said beam into first and second components having orthogonal circular polarizations, the relative intensities of which vary with the relative polarization vector of said detected beam; first and second detectors arranged to receive said first and second components having orthogonal circular polarizations, respectively, and to generate respective outputs D1 and D2 that vary with the intensities of their received components; and circuitry arranged to receive D1 and D2 and to calculate the rotational orientation θ
of said moving platform with respect to said predefined coordinate system, with θ
given by; - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27)
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28. A moving platform guidance system, comprising:
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a transmitter which generates a pulsed beam having a known polarization with respect to a predefined coordinate system; a moving platform, said platform comprising an ellipsometric detector capable of detecting a polarized beam when said ellipsometric detector is within the line-of-sight of said polarized beam, and of measuring said polarized beam'"'"'s polarization state such that said polarization state indicates the rotational orientation of said moving platform with respect to a predefined coordinate system; said ellipsometric detector comprising; a venetian blind component through which said detected polarized beam passes, said component arranged such that the intensity of the beam after it passes through the component varies with the incident angle of said detected beam with respect to the said moving platform; a polarizing beamsplitter which receives said detected beam after it passes through said venetian blind component and splits said beam into first and second components having orthogonal circular polarizations, the relative intensities of which vary with the relative polarization vector of said detected beam, said polarizing beamsplitter including a polarization grating arranged to create angular separation between said orthogonal circular polarizations; first and second detectors arranged to receive said first and second components having orthogonal circular polarizations, respectively, and to generate respective outputs D1 and D2 that vary with the intensities of their received components; a retroreflector arranged to reflect said polarized beam; and circuitry arranged to receive D1 and D2 and to calculate the rotational orientation θ
of said moving platform with respect to said predefined coordinate system, with θ
given by;
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Specification