| Ambient Light Calibration of a Scanning Slope Sensor |
26 JUN 95 |
27 pages |
| Authors:
Mark A. Sletten; Dennis B. Trizna; Paul A. Hwang; NAVAL RESEARCH LAB WASHINGTON DC
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 | This paper outlines a procedure developed to calibrate a laser-based water surface slope sensor against ambient light variations. An analysis of the optical position sensor used in the system indicates how variations in the ambient light intensity cause shifts in the illumination pattern centroid calculated by the sensor electronics. These shifts are misinterpreted as slope variations of the water surface unless special calibration measures are performed. The analysis is also ... |
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| Pacific Marine Radar Sea Scatter Experimental Results |
22 AUG 89 |
29 pages |
| Authors:
Dennis B. Trizna; NAVAL RESEARCH LAB WASHINGTON DC
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| Results are presented for a low grazing angle marine radar sea scatter experiment conducted in the Pacific Ocean. A wide range of wind speeds and directions resulted in non-equilibrium sea conditions, in contrast to a previous Atlantic experiment in which ocean waves were fully developed. Statistical properties of the radar echoes are parameterized by a dual-Weibull model versus wind speed and differ from the North Atlantic data. A modified version ... |
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| Calculated Radar Images of Ship Wakes from Simulated Wake Hydrodynamic Models |
24 MAR 89 |
25 pages |
| Authors:
Dennis B. Trizna; George Keramidas; NAVAL RESEARCH LAB WASHINGTON DC
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| Calculations of radar scatter images from simulated ship wakes are presented for two ships, the Quapaw and a DDG class vessel. Three ship speeds were used for each, scaled so that the Froude numbers were the same for both vessels. Two radar scattering mechanisms were used: Bragg scatter and an empirical sea spike model. No doppler effects are considered so that the model is one for a real-aperture radar. Both ... |
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| Measurement and Interpretation of North Atlantic Ocean Marine Radar Sea Scatter |
31 MAY 88 |
54 pages |
| Authors:
Dennis B. Trizna; NAVAL RESEARCH LAB WASHINGTON DC
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| Results are presented for experiments conducted with a noncoherent, high-resolution marine navigation radar aboard the NOAA ship Researcher in the North Atlantic Ocean. High-resolution radar backscatter data were collected under wind-wave equilibrium conditions, i.e., both fetch and time requirements for fully developed seas were satisfied for the wind speeds reported. Cumulative distributions of normalized radar cross section (NRCS) of the sea surface are calculated and found to follow two Weibull ... |
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| Analysis of Environmental Parameters from the Panama City Tower Radar Experiment |
12 APR 88 |
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| Authors:
Lee U. Martin; Dennis B. Trizna; NAVAL RESEARCH LAB WASHINGTON DC
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 | Wind and wave data have been analyzed for the Panama City Tower Radar Experiment performed by Keller, Plant and Weissmann (1985), for comparison with radar data. Time series of wave height records were analyzed for a variety of definitions of wave height, with the resultant RMS heights calibrated against spectrum analysis results. As a result of the consideration of the wave spectra and wind history, the data are sorted into ... |
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| Definition of Long Ocean Wave Slope for Radar Applications |
04 MAR 88 |
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| Authors:
Dennis B. Trizna; Lee U. Martin; NAVAL RESEARCH LAB WASHINGTON DC
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| Consideration is given to the definition of open ocean long wave slope, as a parameter for correlation with radar section (RCS). In preparation for studies of dependence of short pulse radar statistics on long wave features, we have re-examined the long time averaged RCS data previously reported by Keller, Plant and Weissman (KPW), and its dependence on in-situ measurements of long wave slope. Comparisons of RCS are made with the ... |
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| Method for Sea Surface High Frequency Radar Cross-Section Estimation Using Doppler Spectral Properties. |
30 DEC 1986 |
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| Authors:
Dennis B. Trizna; DEPARTMENT OF THE NAVY WASHINGTON DC
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| A method for estimating the high frequency radar cross-section of the sea surface. A Doppler spectrum of the sea surface is obtained by correlating returns from the high frequency radar signals. Approach and recede Bragg spectral lines and a zero Doppler frequency continuum level are identified in the Doppler spectrum. The amplitude ratio rho between the Bragg spectral lines and an amplitude ratio zeta(m) between the maximum amplitude Bragg spectral ... |
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| Theoretical Antenna Patterns for Sea Echo at San Clemente Island. |
JUL 1976 |
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| Authors:
John C. Moore; Dennis B. Trizna; NAVAL RESEARCH LAB WASHINGTON D C
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| Theoretical product array gains were calculated and plotted for a nonuniformly spaced array of twenty-five side-terminated vertical half-rhombics. The HF radar array, located at the NRL/ITS/NOAA San Clemente Island, is being used as both a ground-wave and sky-wave Doppler radar for sea scatter measurements. The antenna operates at a frequency range of 2-30 MHz and is capable of beam steering over a 40 degree sector in steps the size of ... |
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| WINDVEL2: A Program for Plotting Wind Velocity as Determined by OTH Radar. |
DEC 1974 |
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| Authors:
Mark H. Etzel; Dennis B. Trizna; NAVAL RESEARCH LAB WASHINGTON D C
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| A FORTRAN program has been developed for displaying wind direction and wind speed data maps, as determined by the HF Over-the-Horizon Radar. The output products are a grid of wind direction arrows for each range/azimuth radar cell, and continuous contours of wind speed, plotted on a stereographic projection of the Northern Hemisphere about the North Pole by a CALCOMP 565 plotter or compatible CRT display. Data inputted are generated by ... |
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