Design and Applications of Multi-Frequency Holographic Subsurface Radar: Review and Case Histories

Holographic subsurface radar (HSR) is currently not in widespread usage. This is due to an historical perspective in the ground penetrating radar (GPR) community that the high attenuation of electromagnetic waves in most media of interest, and the inability to apply time-varying gain to the continuous wave (CW) HSR signal precludes sufficient effective penetration depth. While it is true that the fundamental physics of HSR, with its use of a CW signal, does not allow amplification of later (i.e. deeper) arrivals in lossy media (as is possible with impulse subsurface radar — ISR), HSR has distinct some distinctive advantages. The most important of these is the ability to do shallow subsurface imaging with a resolution that is not possible with ISR. In addition, the design of an HSR system is simpler than for ISR due to the relatively low-tech transmitting and receiving antennae. This paper provides a review of the main principles of HSR through an optical analogy and describes possible algorithms for radar hologram reconstruction. We also present a review of the history of development of systems and applications for HSR of the “RASCAN” type which is possibly the only holographic subsurface radar that is produced in lots. Among the subsurface imaging and remote sensing applications considered are humanitarian demining, construction inspection, surveys of historic architecture and artworks, nondestructive testing of dielectric aerospace materials, security applications, paleontology, detection of wood-boring insect damage, and others. Each application is illustrated with relevant data acquired in laboratory and/or field experiments.

Design and Applications of Multi-Frequency Holographic Subsurface Radar: Review and Case Histories

Holographic subsurface radar (HSR) is currently not in widespread usage. This is due to an historical perspective in the ground penetrating radar (GPR) community that the high attenuation of electromagnetic waves in most media of interest, and the inability to apply time-varying gain to the continuous wave (CW) HSR signal precludes sufficient effective penetration depth. While it is true that the fundamental physics of HSR, with its use of a CW signal, does not allow amplification of later (i.e. deeper) arrivals in lossy media (as is possible with impulse subsurface radar — ISR), HSR has distinct some distinctive advantages. The most important of these is the ability to do shallow subsurface imaging with a resolution that is not possible with ISR. In addition, the design of an HSR system is simpler than for ISR due to the relatively low-tech transmitting and receiving antennae. This paper provides a review of the main principles of HSR through an optical analogy and describes possible algorithms for radar hologram reconstruction. We also present a review of the history of development of systems and applications for HSR of the “RASCAN” type which is possibly the only holographic subsurface radar that is produced in lots. Among the subsurface imaging and remote sensing applications considered are humanitarian demining, construction inspection, surveys of historic architecture and artworks, nondestructive testing of dielectric aerospace materials, security applications, paleontology, detection of wood-boring insect damage, and others. Each application is illustrated with relevant data acquired in laboratory and/or field experiments.

Record of the Emerald Ash Borer (Agrilus planipennis) in Ukraine is Confirmed

Agrilus planipennis (Coleoptera: Buprestidae) is a devastating invasive pest of ash trees. This wood-boring insect is native to Asia and established in European Russia about 20 years ago. It severely damages Fraxinus pennsylvanica plantations and quickly spreads. In 2019 we first detected A. planipennis in Ukraine. More than 20 larvae were collected from under the bark of F. pennsylvanica trees on 5 September 2019 in the Markivka District of the Luhansk Region. The coordinates of the localities of collection were 49.614991 N, 39.559743 E; 49.614160 N, 39.572402 E; and 49.597043 N, 39.561811 E. The photos of the damaged trees with larval galleries, exit holes and larvae are presented. It indicates that A. planipennis is established in the east of Ukraine. This fact is important for development of quarantine protocols to prevent or at least slow the further spread of this invasive pest in Europe.

The Stephanidae (Hymenoptera, Stephanoidea) of Iran with the description of a new species

Stephanidae (Hymenoptera, Stephanoidea) are solitary idiobiont ectoparasitoids of wood boring insect larvae. Here we present two genera, i.e., Afromegischus van Achterberg, 2002 and Foenatopus Smith, 1861, and five species, i.e., A. gigas (Schletterer, 1889), F. bisignatus Aguiar & Jennings, 2010, F. crispus Aguiar, 2010, F. nimaarkanii Ghafouri Moghaddam & Rakhshani sp. n. and F. prousti Aguiar & Turrisi, 2010 from Iran. Specimens were collected in southeastern Iran (Kerman and Sistan-o Baluchestan) from unknown hosts. Their morphological features and distribution are discussed in relation to the overall knowledge in the target and adjacent regions. Foenatopus nimaarkanii sp. n. is incorporated to the key for the identification of Foenatopus species with double spots on metasomal tergites.

Record of the Emerald Ash Borer (Agrilus planipennis) in Ukraine is Confirmed

Agrilus planipennis is a devastating invasive pest of ash trees. This wood-boring insect native to Asia and established in European Russia about 20 years ago poses a serious threat to ash trees all over Europe. In 2019 we first detected Agrilus planipennis in Ukraine. More than 20 larvae have been collected from under the bark of Fraxinus pennsylvanica trees on 5 September 2019 in Markivka District of Luhansk Region. Coordinates of the localities of collection: 49.614991 N, 39.559743 E; 49.614160 N, 39.572402 E and 49.597043 N, 39.561811 E. The photos of damaged trees with larval galleries, exit holes and larvae are presented. There is no doubt that the pest is established in Ukraine. This fact is important for development of quarantine protocols to prevent or at least slow the further spread of this invasive pest in Europe.