NASA Scientific and Technical Aerospace Reports

problems associated with available ‘off-the-shelf’ LADAR systems, summarizes world-wide state-of-the-art research, and
elaborates on general trends in advanced LADAR sensor research and their likely impact on manufacturing, autonomous
vehicle mobility and on construction automation.
NTIS
Optical Radar; Radar Detection; Reliability Analysis
20040111174 Lawrence Livermore National Lab., Livermore, CA
Dispersion Compensation Requirements for Optical CDMA Using WDM Lasers
Mendez, A. J.; Hernandez, V. J.; Feng, H. X. C.; Heritage, J. P.; Lennon, W. J.; Dec. 10, 2001; In English
Report No.(s): DE2003-15005687; UCRL-JC-146464; No Copyright; Avail: National Technical Information Service (NTIS)
Optical code division multiple access (O-CDMA) uses very narrow transmission pulses and is thus susceptible to fiber
optic link impairments. When the O-CDMA is implemented as wavelength/time (W/T) matrices which use wavelength
division multiplexing (WDM) sources such as multi-frequency laser transmitters, the susceptibility may be higher due to: (a)
the large bandwidth utilized and (b) the requirement that the various wavelength components of the codes be synchronized
at the point of modulation and encoding as well as after (optical) correlation. A computer simulation based on the nonlinear
Schrodinger equation, developed to study optical networking on the National Transparent Optical Network (NTON), was
modified to characterize the impairments on the propagation and decoding of W/T matrix codes over a link of the NTON.
Three critical link impairments were identified by the simulation: group velocity dispersion (GVD); the flatness of the optical
amplifier gain; and the slope of the GVD. Subsequently, experiments were carried out on the NTON link to verify and refine
the simulations as well as to suggest improvements in the W/T matrix signal processing design. The NTON link measurements
quantified the O-CDMA dispersion compensation requirements. Dispersion compensation management is essential to assure
the performance of W/T matrix codes.
NTIS
Bandwidth; Code Division Multiple Access; Computerized Simulation; Velocity Distribution
20040111281 Physics and Electronics Lab. TNO, The Hague, Netherlands
Sensor Performance Measurements with the IR Zoom-Collimator
deJong, A. N.; Winkel, J.; June 2004; 41 pp.; In English
Contract(s)/Grant(s): TNO Proj. 33132
Report No.(s): TD-2003-0072; FEL-03-A159; Copyright; Avail: Other Sources
In this report a review has been given on the technical and theoretical problems, occumng during performance
measurements and specification of IR cameras. A new device, an infiared zoom-collimator, is described, allowing a rapid
change of the type of target and its orientation. The capability to choose any spatial frequency between 0.6 and 2.5
cycles/milliradian allows a direct measurement of the range limit of a camera. The set-up allows the use of a perception test
following the forced choice method, excluding fraud by the observer. During experiments it was shown that the angle of
orientation has an impact on the recognition range. It was shown, that the asymmetry of the standard 4-bar target limits its
usefulness. In the small details, as occurring in the C-ring target, running phase effects play a major role. Therefore it is
recommended to apply a slow scanning motion to the camera under test.
Author
Cameras; Collimators; Infrared Instruments; Performance Tests
20040111439 Space Telescope Science Inst., Baltimore, MD, USA
Density, Velocity and Ionization Structure in Accretion-Disc Winds
Sonneborn, George, Technical Monitor; Long, Knox; September 21, 2004; 3 pp.; In English
Contract(s)/Grant(s): NAG5-10338; STScI Proj. J0303; No Copyright; Avail: CASI; A01, Hardcopy
This was a project to exploit the unique capabilities of FUSE to monitor variations in the wind- formed spectral lines of
the luminous, low-inclination, cataclysmic variables(CV) -- RW Sex. (The original proposal contained two additional objects
but these were not approved.) These observations were intended to allow us to determine the relative roles of density and
ionization state changes in the outflow and to search for spectroscopic signatures of stochastic small-scale structure and
shocked gas. By monitoring the temporal behavior of blue-ward extended absorption lines with a wide range of ionization
potentials and excitation energies, we proposed to track the changing physical conditions in the outflow. We planned to use
a new Monte Carlo code to calculate the ionization structure of and radiative transfer through the CV wind. The analysis
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