Abstract: An apparatus for determining the location and state of an object in an environment is disclosed. Three or more light-emitting beacons are located in the environment, and each beacon transmits a light pattern that contains information needed to identify the beacon. An optical receiver is attached to the object whose location needs to be determined. The optical receiver comprising one or more cameras images the beacons, and identifies the apparent direction from which the beacon is coming based on the pixel or pixels illuminated by the beacon. The optical receiver also decodes the light pattern transmitted by each beacon to identify it. Finally, based on knowledge of the locations of the beacons in the environment and based on the apparent directions from which the beacons appear to be coming, the optical receiver determines its location, and thus the location of the object.

Abstract: An apparatus for determining the location and state of an object in an environment is disclosed. Three or more light-emitting beacons are located in the environment, and each beacon transmits a light pattern that contains information needed to identify the beacon. An optical receiver is attached to the object whose location needs to be determined. The optical receiver comprising one or more cameras images the beacons, and identifies the apparent direction from which the beacon is coming based on the pixel or pixels illuminated by the beacon. The optical receiver also decodes the light pattern transmitted by each beacon to identify it. Finally, based on knowledge of the locations of the beacons in the environment and based on the apparent directions from which the beacons appear to be coming, the optical receiver determines its location, and thus the location of the object.

Abstract: The ternary alloy CdSexTe1-x(2 1 1) and the quaternary alloy Cd1-zZnzSexTe1-x have been grown on Si(2 1 1) substrates using molecular beam epitaxy (MBE). The growth of CdSeTe is facilitated using a compound CdTe effusion source and a Se effusion source while the growth of CdZnSeTe is facilitated using a compound CdTe effusion source, a compound ZnTe effusion source, and an elemental Se source. The alloy compositions (x) and (z) of CdSexTe1-x ternary compound and Cd1-zZnzSexTe1-x are controlled through the Se/CdTe and ZnTe/CdTe flux ratios. The rate of Se incorporation is higher than the rate of Te incorporation as growth temperature increases. As-grown CdSeTe with 4% Se and CdZnSeTe with 4% Zn+Se, which is substantially lattice matched to long-wavelength infrared HgCdTe materials, exhibits excellent surface morphology, low surface defect density (less than 500 cm2), and a narrow X-ray rocking curve (a full-width at half maximum of 103 arcsec).