Ultrawideband radar echoes of land mine targets measured at oblique incidence using a 250-kW impulse radar system

1997 ◽  
Author(s):  
Ian J. Chant ◽  
Geoff Staines
Keyword(s):  
Oblique Incidence ◽  
Radar System ◽  
Radar Echoes ◽  
Land Mine ◽  
Ultrawideband Radar

scholarly journals Determination of meteor-head echo trajectories using the interferometric capabilities of MAARSY

2013 ◽  
Vol 31 (10) ◽  
pp. 1843-1851 ◽  
Author(s):  
C. Schult ◽  
G. Stober ◽  
J. L. Chau ◽  
R. Latteck
Keyword(s):  
Middle Atmosphere ◽  
Radar System ◽  
Neutral Atmosphere ◽  
Plasma Irregularities ◽  
Radar Systems ◽  
Radar Echoes ◽  
High Kinetic Energy ◽  
Head Echo ◽  
Sporadic Meteors

Abstract. During the flight of a meteoroid through the neutral atmosphere, the high kinetic energy is sufficient to ionize the meteoric constituents. Radar echoes coming from plasma irregularities surrounding the meteoroids are called meteor-head echoes, and can be detected by HPLA radar systems. Measurements of these echoes were conducted with MAARSY (Middle Atmosphere Alomar Radar System) in December 2010. The interferometric capabilities of the radar system permit the determination of the meteor trajectories within the radar beam with high accuracy. The received data are used to gain information about entry velocities, source radiants, observation heights and other meteoroid parameters. Our preliminary results indicate that the majority of meteors have masses between 10−10 and 10−3 kg and the mean masses of the sporadic meteors and Gemenids meteors are ∼10−8 kg.

Spatial relationship of visual arcs to auroral electrojets

1991 ◽  
Vol 69 (8-9) ◽  
pp. 1047-1054 ◽  
Author(s):  
Q. Pao ◽  
L. L. Cogger ◽  
D. D. Wallis ◽  
A. G. McNamara
Keyword(s):  
Electric Field ◽  
Electron Flow ◽  
Spatial Relationship ◽  
Radar System ◽  
Maximum Magnitude ◽  
Temporal Relationships ◽  
Radar Echoes ◽  
E Region ◽  
Relationship Of ◽  
Coherent Backscatter

Observations of the 5577 Å (1 Å = 10−10 m) emission detected with an all-sky imager are superimposed onto maps of auroral E-region coherent backscatter at 50 MHz made by the bistatic auroral radar system (BARS) to obtain the spatial and temporal relationships of stable visual arcs to auroral electrojets and the Harang discontinuity. At large aspect angles, characteristic of BARS, many eastward electron-drift velocities appear poleward of the visual arcs, in agreement with a recent proposed explanation that is based on refraction through auroral ionization structures in the E region. For some observations, the radar echoes are essentially co-located with the visual aurora. When the Harang discontinuity is present, the discrete arc separates the counterstreaming electron flow. Under these circumstances, the electric field in the E region associated with the stable arc agrees with the theoretical electric-field simulation, in which the electric field with a maximum magnitude of 40 mV m−1, reverses direction across the discrete auroral arc. It is also evident from the observations that there is often no obvious spatial correspondence between the visible aurora and the velocity vectors of the electron flow. In some cases there exists electron flow with a large southward component across the stable arc.

Radar detection of subglacial sulfides

Geophysics ◽  
1991 ◽  
Vol 56 (6) ◽  
pp. 870-873 ◽  
Author(s):  
W. R. Hammond ◽  
K. F. Sprenke
Keyword(s):  
Mineral Exploration ◽  
Radar System ◽  
Perfect Conductor ◽  
Southeast Alaska ◽  
Radar Echoes ◽  
Anomalous Reflection ◽  
Reflected Power ◽  
Drill Holes ◽  
Lateral Variations ◽  
Ice Radar

Using an ice radar system, we detected anomalous reflection strengths over subglacial disseminated sulfide zones beneath the Mt. Henry Clay Glacier in southeast Alaska. The subglacial sulfide zones, which were verified by drill holes, were not detected by previous magnetic, helicopter EM, or ground‐based time‐domain EM surveys. The sulfide zones were mapped by measuring lateral variations in the strength of radar echoes from the ice‐bedrock interface at the base of the glacier. The reflected power from these disseminated occurrences ranged from 20 percent to 60 percent of the theoretically predicted reflected power from a perfect conductor at the base of the ice. The empirical results of this experiment suggest that ice radar may be a useful tool for direct mineral exploration in ice‐covered terrain.

Scattering Rings in Birefringent Porous Silicon

2003 ◽  
Vol 762 ◽  
Author(s):  
Claudio J. Oton ◽  
Zeno Gaburro ◽  
Mher Ghulinyan ◽  
Nicola Daldosso ◽  
Lucio Pancheri ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Light Scattering ◽  
Porous Silicon ◽  
Direct Measurement ◽  
Optical Anisotropy ◽  
Oblique Incidence ◽  
Laser Light ◽  
Anisotropic Scattering ◽  
Scattering Measurements

AbstractWe report the observation of strongly anisotropic scattering of laser light at oblique incidence on (100)-oriented porous silicon layers. We performed angle-resolved light scattering measurements and three concentric rings were observed. Modeling porous silicon by means of nanometric columnar air pores and an effective anisotropic uniaxial dielectric constant explains the observed phenomenon, and besides, the observation of the angle aperture of these rings allows a direct measurement of relative birefringence. We finally study the changes of optical anisotropy after different modifications of the structure.

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