Patents by Inventor David N. Sitter

David N. Sitter has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Publication number: 20220026727
    Abstract: A beam splitter configured to split incident light includes a polarization grating having a liquid crystal layer and a reflective sub-aperture beam splitter. The liquid crystal layer is configured to switch between an “on” state and an “off” state in response to an applied voltage. In the “off” state, the polarization grating angularly deviates and polarizes a portion of received incident light passing therethrough. In the “on” state, crystals of the polarization grating align with the incident light, allowing it to pass therethrough unimpeded and unpolarized. The beam splitter includes a plurality of sub-aperture mirrors which are spaced at randomly varying distances from one another, the mirrors being configured to reflect a portion of the incident light.
    Type: Application
    Filed: July 23, 2020
    Publication date: January 27, 2022
    Applicant: Raytheon Company
    Inventor: David N. Sitter, Jr.
  • Publication number: 20210255325
    Abstract: A coherent imaging system produces coherent flood illumination directed toward a remote object and local oscillator (LO) illumination derived based on a same master oscillator as the flood illumination. A Doppler sensor receives the LO illumination and a return of flood illumination reflected off the object. Doppler shift data from the Doppler sensor, corresponding to a longitudinal velocity of the object relative to the imaging system, is used to produce Doppler-shifted LO illumination received by a low bandwidth, large format focal plane array (FPA), together with the return illumination from the object. Interference between the Doppler-shifted LO illumination and the return illumination facilitates producing an image of the object with the low bandwidth FPA despite the longitudinal velocity. Pixel intensities from the FPA are integrated over a period approaching the maximum interference frequency. The Doppler sensor and FPA may concurrently process return for a high energy laser target spot.
    Type: Application
    Filed: April 16, 2021
    Publication date: August 19, 2021
    Inventors: Joseph Marron, Maurice J. Halmos, Justin S. Grayer, David N. Sitter, JR., Gamze Erten
  • Patent number: 10996336
    Abstract: A coherent imaging system produces coherent flood illumination directed toward a remote object and local oscillator (LO) illumination derived based on a same master oscillator as the flood illumination. A Doppler sensor receives the LO illumination and a return of flood illumination reflected off the object. Doppler shift data from the Doppler sensor, corresponding to a longitudinal velocity of the object relative to the imaging system, is used to produce Doppler-shifted LO illumination received by a low bandwidth, large format focal plane array (FPA), together with the return illumination from the object. Interference between the Doppler-shifted LO illumination and the return illumination facilitates producing an image of the object with the low bandwidth FPA despite the longitudinal velocity. Pixel intensities from the FPA are integrated over a period approaching the maximum interference frequency. The Doppler sensor and FPA may concurrently process return for a high energy laser target spot.
    Type: Grant
    Filed: January 5, 2016
    Date of Patent: May 4, 2021
    Assignee: Raytheon Company
    Inventors: Joseph Marron, Maurice J. Halmos, Justin S. Grayer, David N. Sitter, Jr., Gamze Erten
  • Patent number: 10969578
    Abstract: An unobscured five-mirror afocal telescope includes an aperture configured to direct electromagnetic radiation to first, second, third, fourth and fifth mirrors, each configured to receive electromagnetic radiation and reflect electromagnetic radiation along a beam path. The five mirrors are arranged to sequentially reflect from one another electromagnetic radiation received via the aperture to produce a collimated output beam of the electromagnetic radiation at an exit pupil, with the five mirrors consisting of a three-element objective and a two-element eyepiece. A beam splitter may be disposed between the first mirror and the second mirror to direct short-wavelength electromagnetic radiation toward a device along a separate path.
    Type: Grant
    Filed: March 11, 2019
    Date of Patent: April 6, 2021
    Assignee: RAYTHEON COMPANY
    Inventor: David N. Sitter, Jr.
  • Publication number: 20210026128
    Abstract: An on-axis four mirror anastigmat telescope includes an entrance pupil configured to receive light from an image, and a mirror assembly. The mirror assembly has a first reflective surface having a central aperture formed therein, a second reflective surface, a third reflective surface having a central aperture formed therein, a fourth reflective surface, and an aperture stop. The mirror assembly is configured to receive light from the image on a common axis and to reflect the light successively by the four coaxial reflective surfaces through the aperture stop. The telescope further comprises a detector configured to receive light from the mirror assembly. The central aperture formed in the first reflective surface defines a field stop to limit the field of view.
    Type: Application
    Filed: May 7, 2020
    Publication date: January 28, 2021
    Inventor: David N. Sitter, JR.
  • Publication number: 20200292811
    Abstract: An unobscured five-mirror afocal telescope includes an aperture configured to direct electromagnetic radiation to first, second, third, fourth and fifth mirrors, each configured to receive electromagnetic radiation and reflect electromagnetic radiation along a beam path. The five mirrors are arranged to sequentially reflect from one another electromagnetic radiation received via the aperture to produce a collimated output beam of the electromagnetic radiation at an exit pupil, with the five mirrors consisting of a three-element objective and a two-element eyepiece. A beam splitter may be disposed between the first mirror and the second mirror to direct short-wavelength electromagnetic radiation toward a device along a separate path.
    Type: Application
    Filed: March 11, 2019
    Publication date: September 17, 2020
    Inventor: David N. Sitter, JR.
  • Patent number: 10754038
    Abstract: An apparatus includes at least one processor configured to determine a wavefront phase profile of return illumination reflected from a remote object, where the wavefront phase profile is based on interference between Doppler-shifted local oscillator (LO) illumination and the return illumination. The at least one processor is also configured to calculate a wavefront error based on a comparison between (i) the determined wavefront phase profile of the return illumination and (ii) a desired wavefront phase profile of a high energy laser (HEL) beam. The at least one processor is further configured to control a deformable mirror to at least partially compensate the HEL beam for the calculated wavefront error.
    Type: Grant
    Filed: May 6, 2019
    Date of Patent: August 25, 2020
    Assignee: Raytheon Company
    Inventors: Joseph Marron, Maurice J. Halmos, Justin S. Grayer, Gamze Erten, David N. Sitter, Jr.
  • Patent number: 10690903
    Abstract: Examples are directed to optimal field mappings that provide the highest contrast images for back-scanned imaging methods. The mappings can be implemented for back-scanned imaging with afocal optics including an anamorphic field correcting assembly configured to implement a non-rotationally symmetric field mapping between object space and image space to adjust distortion characteristics of the afocal optics to control image wander on a focal plane array. The anamorphic field correcting assembly can include one or more mirrors or lenses having non-rotationally symmetric aspherical departures.
    Type: Grant
    Filed: May 24, 2018
    Date of Patent: June 23, 2020
    Assignee: RAYTHEON COMPANY
    Inventor: David N. Sitter, Jr.
  • Patent number: 10502951
    Abstract: An apparatus includes a wavefront sensor configured to receive coherent flood illumination that is reflected from a remote object and to estimate wavefront errors associated with the coherent flood illumination. The apparatus also includes a beam director optically coupled to the wavefront sensor and having a telescope and an auto-alignment system. The auto-alignment system is configured to adjust at least one first optical device in order to alter a line-of-sight of the wavefront sensor. The wavefront errors estimated by the wavefront sensor include a wavefront error resulting from the adjustment of the at least one first optical device. The beam director could further include at least one second optical device configured to correct for the wavefront errors. The at least one second optical device could include at least one deformable mirror.
    Type: Grant
    Filed: June 7, 2016
    Date of Patent: December 10, 2019
    Assignee: Raytheon Company
    Inventors: David N. Sitter, Jr., Joseph Marron, Maurice J. Halmos, Joseph J. Ichkhan, Justin S. Grayer, Gamze Erten
  • Patent number: 10401499
    Abstract: A laser beam projection system builds on a coherent imaging to project a tightly focused laser beam onto a remote object. Coherent flood illumination and local oscillator (LO) illumination are based on one master oscillator. The coherent flood illumination is directed toward a remote object, with a second laser beam directed onto an aimpoint on the same object. A Doppler sensor provides Doppler shift data used to produce Doppler-shifted LO illumination received by a focal plane array, together with the return flood illumination. Interference between the Doppler-shifted LO illumination and the return flood illumination facilitates imaging the object despite the velocity. The wavefront error of the flood illumined remote object image is computed and compared to the desired wavefront of the second laser beam at the aimpoint, with the difference applied to a deformable mirror to shape the second laser beam wavefront for obtaining a desired aimpoint intensity profile.
    Type: Grant
    Filed: March 16, 2016
    Date of Patent: September 3, 2019
    Assignee: Raytheon Company
    Inventors: Joseph Marron, Maurice J. Halmos, Justin S. Grayer, Gamze Erten, David N. Sitter, Jr.
  • Publication number: 20190265362
    Abstract: An apparatus includes at least one processor configured to determine a wavefront phase profile of return illumination reflected from a remote object, where the wavefront phase profile is based on interference between Doppler-shifted local oscillator (LO) illumination and the return illumination. The at least one processor is also configured to calculate a wavefront error based on a comparison between (i) the determined wavefront phase profile of the return illumination and (ii) a desired wavefront phase profile of a high energy laser (HEL) beam. The at least one processor is further configured to control a deformable mirror to at least partially compensate the HEL beam for the calculated wavefront error.
    Type: Application
    Filed: May 6, 2019
    Publication date: August 29, 2019
    Inventors: Joseph Marron, Maurice J. Halmos, Justin S. Grayer, Gamze Erten, David N. Sitter, JR.
  • Patent number: 10394007
    Abstract: Optimal angular field mappings that provide the highest contrast images for back-scanned imaging are given. The mapping can be implemented for back-scanned imaging with afocal optics including an anamorphic field correcting assembly configured to implement a non-rotationally symmetric field mapping between object space and image space to adjust distortion characteristics of the afocal optics to control image wander on a focal plane array. The anamorphic field correcting assembly can include one or more mirrors having non-rotationally symmetric aspherical departures.
    Type: Grant
    Filed: October 17, 2017
    Date of Patent: August 27, 2019
    Assignee: RAYTHEON COMPANY
    Inventor: David N. Sitter, Jr.
  • Patent number: 10379337
    Abstract: Examples are directed to optimal field mappings that provide the highest contrast images for time delay integration (TDI) imaging systems and methods. The mapping can be implemented for line-scanned imaging with optical systems including an anamorphic field correcting assembly configured to implement a non-rotationally symmetric field mapping between object space and image space to adjust distortion characteristics of the optics to control image wander on a focal plane array. The anamorphic field correcting assembly can include one or more mirrors or lenses having non-rotationally symmetric aspherical departures.
    Type: Grant
    Filed: May 24, 2018
    Date of Patent: August 13, 2019
    Assignee: RAYTHEON COMPANY
    Inventor: David N. Sitter, Jr.
  • Patent number: 10330929
    Abstract: A method for cross-band apochromatic correction in a multi-element optical system.
    Type: Grant
    Filed: July 26, 2016
    Date of Patent: June 25, 2019
    Assignee: RAYTHEON COMPANY
    Inventor: David N. Sitter, Jr.
  • Publication number: 20190113736
    Abstract: Optimal angular field mappings that provide the highest contrast images for back-scanned imaging are given. The mapping can be implemented for back-scanned imaging with afocal optics including an anamorphic field correcting assembly configured to implement a non-rotationally symmetric field mapping between object space and image space to adjust distortion characteristics of the afocal optics to control image wander on a focal plane array. The anamorphic field correcting assembly can include one or more mirrors having non-rotationally symmetric aspherical departures.
    Type: Application
    Filed: October 17, 2017
    Publication date: April 18, 2019
    Inventor: David N. Sitter, JR.
  • Publication number: 20180307033
    Abstract: Examples are directed to optimal field mappings that provide the highest contrast images for time delay integration (TDI) imaging systems and methods. The mapping can be implemented for line-scanned imaging with optical systems including an anamorphic field correcting assembly configured to implement a non-rotationally symmetric field mapping between object space and image space to adjust distortion characteristics of the optics to control image wander on a focal plane array. The anamorphic field correcting assembly can include one or more mirrors or lenses having non-rotationally symmetric aspherical departures.
    Type: Application
    Filed: May 24, 2018
    Publication date: October 25, 2018
    Inventor: David N. Sitter, JR.
  • Publication number: 20180284420
    Abstract: Examples are directed to optimal field mappings that provide the highest contrast images for back-scanned imaging methods. The mappings can be implemented for back-scanned imaging with afocal optics including an anamorphic field correcting assembly configured to implement a non-rotationally symmetric field mapping between object space and image space to adjust distortion characteristics of the afocal optics to control image wander on a focal plane array. The anamorphic field correcting assembly can include one or more mirrors or lenses having non-rotationally symmetric aspherical departures.
    Type: Application
    Filed: May 24, 2018
    Publication date: October 4, 2018
    Inventor: David N. Sitter, JR.
  • Publication number: 20180267299
    Abstract: An apparatus includes a wavefront sensor configured to receive coherent flood illumination that is reflected from a remote object and to estimate wavefront errors associated with the coherent flood illumination. The apparatus also includes a beam director optically coupled to the wavefront sensor and having a telescope and an auto-alignment system. The auto-alignment system is configured to adjust at least one first optical device in order to alter a line-of-sight of the wavefront sensor. The wavefront errors estimated by the wavefront sensor include a wavefront error resulting from the adjustment of the at least one first optical device. The beam director could further include at least one second optical device configured to correct for the wavefront errors. The at least one second optical device could include at least one deformable mirror.
    Type: Application
    Filed: June 7, 2016
    Publication date: September 20, 2018
    Inventors: David N. Sitter, JR., Joseph Marron, Maurice J. Halmos, Joseph J. lchkhan, Justin S. Grayer, Gamze Erten
  • Patent number: 10001636
    Abstract: Optimal field mappings that provide the highest contrast images for back-scanned and time delay integration (TDI) imaging are given. The mapping can be implemented for back-scanned imaging with afocal optics including an anamorphic field correcting assembly configured to implement a non-rotationally symmetric field mapping between object space and image space to adjust distortion characteristics of the afocal optics to control image wander on a focal plane array. The anamorphic field correcting assembly can include one or more mirrors or lenses having non-rotationally symmetric aspherical departures. For optimal TDI imaging, anamorphic optics are also employed.
    Type: Grant
    Filed: April 14, 2016
    Date of Patent: June 19, 2018
    Assignee: RAYTHEON COMPANY
    Inventor: David N. Sitter, Jr.
  • Publication number: 20180031828
    Abstract: A method for cross-band apochromatic correction in a multi-element optical system.
    Type: Application
    Filed: July 26, 2016
    Publication date: February 1, 2018
    Inventor: David N. Sitter, JR.