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This paper introduces the current radar intra-pulse modulation method, describes the status quo and development direction of the intentional modulation and unintentional modulation in the pulse, and summarizes the existing problems and prospects for the future. Looking forward to the future, and providing a reference direction for the research on radar signal recognition in the next step. [ABSTRACT FROM AUTHOR]

Quantitative radar precipitation estimates are affected by errors determined by many causes such as radar miscalibration, range degradation, attenuation, ground clutter, variability of Z-R relation, variability of drop size distribution, vertical air motion, anomalous propagation and beam-blocking. Range degradation (including beam broadening and sampling of precipitation at an increasing altitude)and signal attenuation, determine a range dependent behavior of error. The aim of this work is to model the range-dependent error through an adjustment factor derived from the G/R ratio trend against the range, where G and R are the corresponding rain gauge and radar rainfall amounts computed at each rain gauge location. Since range degradation and signal attenuation effects are negligible close to the radar, resultsshowthatwithin 40 km from radar the overall range error is independent of the distance from Polar 55C and no range-correction is needed. Nevertheless, up to this distance, the G/R ratiocan showa concave trend with the range, which is due to the melting layer interception by the radar beam during stratiform events. [ABSTRACT FROM AUTHOR]

Detection of water level in silty soils can be complicated because of capillary action. In this study, the water level in a silty soil sample was detected using Ground Penetrating Radar (GPR) technique in the laboratory. The soil sample has dimensions of 62 cm × 48 cm × 46 cm and was kept in a clear Plexiglas container which facilitated water level measurements. Two ground-coupled antennas with frequencies of 900 MHz and 1,500 MHz were used in this study. The soil sample was dry at the beginning of the experiment. The water level in the soil sample was raised to a pre-determined level and radar readings were taken at different times over 24 hours. The moisture content in the soil sample above the water level increased with time due to capillary action. At the end of the experiment, the variation of moisture content with depth of the sample was experimentally determined. The GPR observations were compared with measured water depth in the soil sample. The paper presents the comparison of water level as determined by GPR with the variation of experimentally determined moisture content in the silty soil sample. This study includes an investigation on the effects of capillary action on GPR measurements. © 2007 American Institute of Physics [ABSTRACT FROM AUTHOR]

Presently there are no suitable non-invasive methods for precisely detecting the subsurface defects in logs in real time. Internal defects such as knots, decays, and embedded metals are of greatest concern for lumber production. Nondestructive scanning of logs using Ground Penetrating Radar (GPR) to detect defects in logs prior to sawing can greatly increase the productivity and yield of high value lumber, and prevent damage to saw blade from embedded metals. In this research, the GPR scanned data has been analyzed to detect subsurface defects such as metals, decays, and knots. Also, GPR offers high speed scanning capability which is needed for future on-line implementation in saw mills. This paper explains the advantages of the GPR technique, experimental setup and parameters used, and data processing for detection of subsurface defects in logs. The results show that GPR can be a very promising technique for future on-line implementation in saw mills. © 2007 American Institute of Physics [ABSTRACT FROM AUTHOR]

The LOFAR Outrigger In Scandinavia (LOIS) is planned to be an addition to the LOFAR (Low Frequency Array) project currently being built in the Netherlands. LOIS will provide radar capabilities and fully digital sensors capable of getting complete vectorial information on electricmagnetic fields. The prime scientific targets will be space and solar physics, but a wide range of research possibilities from advanced computer science to astrophysics will be opened up with LOIS. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

In this paper, we compute coherent structures based on radar data collected in Monterey Bay during August 2001 and August 2003. The Lagrangian structures are extracted from a finite-time Lyapunov exponent field. In contrast with earlier approaches, the integration time used in computing the Lyapunov exponents is not constant but adapts to the timescales of the different flow regimes present in the radar data. Nowcasts of the radar data are performed using open-boundary modal analysis (OMA) and the projection coefficients of this filtering method are used to identify periods corresponding to different dynamical regimes in the bay. Lyapunov exponents are computed within a single dynamical regime, hence they determine dynamically consistent coherent structures. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]

In this paper another evolving way using penetrating life-detective radar to detect the existence of human movement is proposed and also a corresponding method to detect the human movement track. First we analyze the feasibility of this approach. Then we build the entire signal processing of the detection of human-motion track and achieve some experimental results. In the end plots agglomeration was applied to the motion track data and we achieve a more precise effect. [ABSTRACT FROM AUTHOR]