Abstract: Yarns are described herein which, in some embodiments, comprise plies or single strands dyed with at least one vat dyestuff yielding a tweed or heathered appearance. In one aspect, a yarn comprises a first ply and a second ply each dyed with at least one vat dyestuff, wherein a difference in color depth (DL*) between the dyed first single strand and the dyed second single strand has an absolute value of at least 2 when the vat dyestuff is in an oxidized state. As described further herein, the first ply and the second ply are dyed in the same dyebath. In another aspect, a yarn comprises a first ply and a second ply each dyed with at least one vat dyestuff, wherein a reflectance ration between the second ply and the first ply ranges from 0.05 to 0.95.

Abstract: A calibration method comprises providing a mounting fixture including a tray coupled to a frame, and an alignment measurement sensor removably coupled to the tray. An angular orientation of the tray is determined using the alignment measurement sensor removably coupled to the tray in a first position. The alignment measurement sensor is then moved to a second position on the tray that is rotated from the first position, and the angular orientation of the tray is determined using the alignment measurement sensor at the second position. An axis misalignment for at least two of a pitch axis, a roll axis, or a yaw axis of the alignment measurement sensor is then calculated to determine one or more misalignment factors. The one or more misalignment factors are then applied to correct for misalignment of the alignment measurement sensor.

Abstract: A boresight alignment system is disclosed. The system comprises a frame movement sensor operable to determine a reference position on an object, a frame alignment sensor operable to determine a first boresight position on the object, a data acquisition processing unit in communication with the frame movement and frame alignment sensors and a display processing unit in communication with the data acquisition processing unit. The display processing unit is operable to display near real time attitude data measured by the frame movement and frame alignment sensors. The data acquisition processing unit comprises program instructions to correct for angular differences with respect to a reference position.

Abstract: A boresight alignment system is disclosed. The system comprises a frame movement sensor operable to determine a reference position on an object, a frame alignment sensor operable to determine a first boresight position on the object, a data acquisition processing unit in communication with the frame movement and frame alignment sensors and a display processing unit in communication with the data acquisition processing unit. The display processing unit is operable to display near real time attitude data measured by the frame movement and frame alignment sensors. The data acquisition processing unit comprises program instructions to correct for angular differences with respect to a reference position.

Abstract: A method for installation alignment of an inertial reference unit (IRU) with vehicle axes when the IRU is installed within the vehicle is provided. The vehicle axes include roll, pitch, and yaw axes. The method includes recording vehicle angular position data including roll and pitch, using an angular position measurement device with the vehicle being in a starting position, recording IRU data including roll and pitch, receiving measured nose plunge data, computing initial roll and pitch misalignment corrections, applying initial roll and pitch misalignment corrections to measured nose plunge data. A nose plunge yaw misalignment is determined using corrected nose plunge data and utilized to adjust the assumed heading reference.

Abstract: A method for installation alignment of an inertial reference unit (IRU) with vehicle axes when the IRU is installed within the vehicle is provided. The vehicle axes include roll, pitch, and yaw axes. The method includes recording vehicle angular position data including roll and pitch, using an angular position measurement device with the vehicle being in a starting position, recording IRU data including roll and pitch, receiving measured nose plunge data, computing initial roll and pitch misalignment corrections, applying initial roll and pitch misalignment corrections to measured nose plunge data. A nose plunge yaw misalignment is determined using corrected nose plunge data and utilized to adjust the assumed heading reference.