Abstract: In a method of determining the position of an object, raw image data of the sky is recorded using a celestial imaging unit. The last known position, orientation, date, and time data of the object are obtained, and the position of a celestial body is measured. A latitude and longitude of the object is determined by matching the measured celestial body position to the expected celestial body position based on the input parameters. A system for determining a new position of an object comprises a celestial imaging unit configured to record image data of the sky, a signal processing unit, and a signal processing unit configured to receive and store in memory the image data received from the celestial imaging unit. The signal processing unit filters the image to find the positions of celestial objects in the sky. The signal processing unit is further configured to use roll and pitch from an IMU, and date and time from a clock to determine the object's position (latitude and longitude).

Abstract: In a method of determining the position of an object, raw image data of the sky is recorded using a celestial imaging unit. The last known position, orientation, date, and time data of the object are obtained, and the position of a celestial body is measured. A latitude and longitude of the object is determined by matching the measured celestial body position to the expected celestial body position based on the input parameters. A system for determining a new position of an object comprises a celestial imaging unit configured to record image data of the sky, a signal processing unit, and a signal processing unit configured to receive and store in memory the image data received from the celestial imaging unit. The signal processing unit filters the image to find the positions of celestial objects in the sky. The signal processing unit is further configured to use roll and pitch from an IMU, and date and time from a clock to determine the object's position (latitude and longitude).

Abstract: A system for determining a new orientation and/or position of an object comprises a sky polarimeter configured to record image data of the sky, a signal processing unit, and logic configured to receive and store in memory the image data received from the sky polarimeter. The logic calculates the Stokes parameters (S0, S1, S2,), DoLP, and AoP from the image data, detects obscurants and filters the obscurants (such as clouds and trees) from the image data to produce a filtered image. The logic is further configured to find the Sun and zenith in the filtered image, and to determine the roll, pitch, yaw, latitude and longitude of the object using the filtered image.

Abstract: A system for determining a new orientation and/or position of an object comprises a sky polarimeter configured to record image data of the sky, a signal processing unit, and logic configured to receive and store in memory the image data received from the sky polarimeter. The logic calculates the Stokes parameters (S0, S1, S2,), DoLP, and AoP from the image data, detects obscurants and filters the obscurants (such as clouds and trees) from the image data to produce a filtered image. The logic is further configured to find the Sun and zenith in the filtered image, and to determine the roll, pitch, yaw, latitude and longitude of the object using the filtered image.

Abstract: A reflectometer and a method for measuring the reflectance and transmittance of material using an integrating sphere and a light concentrator. The reflectance and transmittance measurements are performed as a function of the angle of incidence of a beam of light onto a sample and reference material. In a preferred embodiment, a CHC-lens concentrator having a high f/# and a low index of refraction is used.

Abstract: An infrared achromatic waveplate structure having a cadmium sulfide (CdS) plate and a cadmium selenide (CdSe) plate aligned with each other so that the fast axis of the plates are perpendicular to each other, this structure provides a desired retardance of a first orthogonal polarization component with respect to a second orthogonal polarization component of an incident light beam. The thickness of the plates are in a ratio between 0.8:1 and 0.9:1 (CdSe:CdS), an achromatic response with a substantially constant retardance is provided in a wavelength range from 3 to 11 microns. A desired amount of retardance is available by adjusting the thickness of the two plates as long as the ratio of the thicknesses is maintained within the recited value. In particular a quarter wave net retardance of an incident light beam operating between 3 and 11 microns is provided when the cadmium sulfide plate is 1.25 millimeters and the cadmium selenide plate is 1.0666 millimeters.