[en] The natural cumulative distributions of rainfall observed by a network of rain gauges and a multiparameter radar are matched to derive multiparameter radar algorithms for rainfall estimation. The use of multiparameter radar measurements in a statistical framework to estimate rainfall is resented in this paper, The techniques developed in this paper are applied to the radar and rain gauge measurement of rainfall observed in central Florida and central Italy. Conventional pointwise estimates of rainfall are also compared. The probability matching procedure, when applied to the radar and surface measurements, shows that multiparameter radar algorithms can match the probability distribution function better than the reflectivity-based algorithms. It is also shown that the multiparameter radar algorithm derived matching the cumulative distribution function of rainfall provides more accurate estimates of rainfall on the ground in comparison to any conventional reflectivity-based algorithm

[en] The United States Department of Energy (US DOE) is developing a Geophysical Performance Evaluation Range (GPER) at Rabbit Valley located 30 miles west of Grand Junction, Colorado. The purpose of the range is to provide a test area for geophysical instruments and survey procedures. Assessment of equipment accuracy and resolution is accomplished through the use of static and dynamic physical models. These models include targets with fixed configurations and targets that can be re-configured to simulate specific specifications. Initial testing (1991) combined with the current tests at the Rabbit Valley GPER will establish baseline data and will provide performance criteria for the development of geophysical technologies and techniques. The US DOE's Special Technologies Laboratory (STL) staff has conducted a Ground Penetrating Radar (GPR) survey of the site with its stepped FM-CW GPR. Additionally, STL contracted several other geophysical tests. These include an airborne GPR survey incorporating a ''chirped'' FM-CW GPR system and a magnetic survey with a surfaced-towed magnetometer array unit Ground-based and aerial video and still frame pictures were also acquired. STL compiled and analyzed all of the geophysical maps and created a site characterization database. This paper discusses the results of the multi-sensor geophysical studies performed at Rabbit Valley and the future plans for the site

[en] This volume is divided into two parts: underground and obscured object imaging and detection and surveillance technologies. The first part is subdivided into the following sessions: system development and demonstration (sessions 1, 2, 3) and analysis and processing algorithms (session 4). Separate abstracts were prepared for most of the papers in this volume

[en] The system of non-cooperative passive location based on array is proposed. In the system, target is detected by beamforming and Doppler matched filtering; and bearing is measured by a long-base-ling interferometer which is composed of long distance sub-arrays. For the interferometer with long-base-line, the bearing is measured accurately but ambiguously. To realize unambiguous accurately bearing measurement, beam width and multiple constraint adoptive beamforming technique is used to resolve azimuth ambiguous. Theory and simulation result shows this method is effective to realize accurately bearing measurement in no-cooperate passive location system. (authors)

[en] The latent heat released in the clouds over the tropics plays a vital role in driving the Hadley circulation (HC). The present study discusses the influence of latent heating (LH) on the HC parameters viz., centre, strength and total width by using precipitation LH profiles derived from the space-borne observations of the Precipitation Radar (PR) onboard Tropical Rain Measuring Mission (TRMM) and meridional stream function (MSF) derived from ECMWF-Interim reanalysis. The latitude of peak latent heating, width of the latent heating distribution and the total LH released within the ascending limb of the HC are estimated and their influence on the HC centre, strength and width is quantified, for the first time. The present results show that the latitude of peak LH significantly influences the position of the HC centre with correlation coefficient of ~ 0.90. This high correlation between these two quantities seems to be due to their co-variability with the apparent motion of the Sun across the latitudes. The intensity of the HC in the NH as well as SH shows high correlation with the latitude of peak LH with coefficients − 0.85 and − 0.78, respectively. These results indicate that farther the latitude of peak LH from the equator in the summer hemisphere, stronger is the HC intensity in the winter hemisphere. The present analysis also reveals that the total LH released within the ascending limb of HC substantially influence the total width of the HC, with correlation coefficient ~ 0.52, as compared to the other two LH parameters. This observation can be attributed to the fact that the HC is sensitive to the latent heat release in the mid-tropospheric levels in the tropics. An attempt is also made to investigate the degree of variability of these parameters after deseasonalization and results are discussed in the light of present understanding. The significance of the present study lies in providing the observational evidence for the influence of latent heating on the HC strength/width variability, quantitatively, for the first time using TRMM observations of precipitation latent heating.

[en] Pulse Compression (PC) is applied in radar systems to enhance range resolution and simultaneously preserve a high duty cycle. PC phase coded radars suffer from unwanted side-lobes at the Matched Filter (MF) output which may mask weak nearby signals. Different methods have been applied to deal with this problem. Each method is designed and applied particularly for certain phase coded signal. In this paper, a generic mathematical formula for a Side-Lobe Cancelling (SLC) Optimum Filter (OP-F) in phase coded pulse compression waveforms is presented. The derived filter followed the MF and can be applied to any type of phase coded signals with any length. The validity of the derived formula is verified for Barker, polyBarker and polyphase coded signals. The enhanced detection performance of the OP-F over MF alone is verified though receiver detection curves. Also, Implementation issues of the OP-F in either time and frequency domain are discussed. (paper)

[en] A planning methodology for developing a radar system to protect nuclear materials facilities from the airborne threat is presented. Planning for physical security to counter the airborne threat is becoming even more important because hostile acts by terrorists are increasing and airborne platforms that can be used to bypass physical barriers are readily available. The comprehensive system planning process includes threat and facility surveys, defense hardening, analysis of detection and early warning requirements, optimization of sensor mix and placement, and system implementation considerations

[en] Radar data recorded during 1993 and 1994 by using the forward-scatter meteor radar of the National Research Council (CNR), enable us to obtain a measurement of the terrestrial mass accretion rate in the cosmic dust mass range 10^-12 to 10^-7 kg. This value results to be 5.4 · 10⁷ kg per year and is in good agreement with previous estimates obtained from other authors (Love S.G. and Brownlee D.E., Science, 262 (1993) 550). Calculations are possible only by taking into account some statistical data series and extrapolation toward higher mass ranges appears to be misleading

[en] A two-dimensional (2D) coding phase gradient metasurface (CPGM) is proposed for radar cross section (RCS) reduction in this work. The 2D phase gradient super cell is employed to serve as the coding element. The primary pattern of the coding element will be modulated by the designed 2D phase gradient. Thus, a more flexible method of scattering manipulation will be achieved by both the 2D phase gradient and coding sequences. The specific scattering patterns of the 2D CPGM under the modulation of phase gradient and coding sequence were analyzed. A controllable backward diffusion scattering coding phase gradient metasurface was realized based on Pancharatnam–Berry phase by modulating both the phase gradient and coding sequence. Both simulated and measured results demonstrate its excellent performance on RCS reduction. (paper)

[en] Passive Detection Network Composed of Multi-Radar Reconnaissance Station, which can receive multiple sets of radar signal pulse descriptor word at the same time, joint signal sorting becomes an inevitable measure of such data. This paper proposes a multi-radar time-aligned association sorting method, and builds scenario close to actual conditions for testing. The results show that method can overcome the problem of partial pulse loss leading to sorting failure, and can quickly complete complex radar signal sorting in real electromagnetic environment. (paper)