A traditional radar actively transmits pulses and receive the corresponding echoes. By computing time taken to echoes system is able detect targets estimate their ranges. However, mainly for military applications, an active has a major drawback: it can be detected by enemy since radiates electromagnetic pulses. As such, there currently high research development activity in field of passive syst...

Abstract Square-wave pulse generation with a variable duty ratio can be realized the help of ideas Talbot array illuminators formulated for binary phase gratings. A temporal modulation continuous wave (CW) laser field propagating through group-delay-dispersion circuit fractional length P...

The Global Navigation Satellite System (GNSS)-based passive bistatic radar (PBR) which uses the GNSS signal as illuminators of opportunity is studied for moving target detection (MTD). GNSS-based PBR has many advantages due to removal transmitting device; however, its fundamental limitation low power density signal. Therefore, integration time should be sufficiently long obtain a promising maxi...

In the last decades, working methods of late medieval illuminators have been widely discussed by art historians and codicologists. Non-invasive analyses are able to characterise painting as well investigate artistic collaborations among them. The aim this study was palettes techniques different artists who illuminated two leaves from an early fourteenth century manuscript. were carried out with...

Crenits Bedel is a small hydrophilid genus of 41 species (Hansen, 1999; Hebauer, 1994, 2005), distributed across Eurasia, Africa and the Americas. The genus is particularly diverse in temperate regions, with the eastern Palaearctic and Nearctic regions containing the highest concentrations of taxa. The eight described African species are all restricted to temperate South Africa, most being foun...

Rather than emitting pulses, passive radar systems rely on illuminators of opportunity, such as TV and FM radio, to illuminate potential targets. These systems are particularly attractive since they allow receivers to operate without emitting energy, rendering them covert. Many existing passive radar systems estimate the locations and velocities of targets. This paper focuses on adding an autom...

Stereograms mark a threshold in understanding visual perception. Modern study of stereopsis began with Wheatstone's invention of the stereogram and stereoscope (~1832) 1 , important tools in vision research and technical imagery ever since 2,3. Stereoscopic images formed with frieze and wallpaper patterns in illuminated Insular manuscripts 4 such as the Book of Durrow (~680 CE) 5 , Lindisfarne ...

The separation of transmitter and receiver in bistatic and multistatic radar sensors offers the system designer new and additional degrees of freedom to tailor solutions to specific applications. The receivers may be passive and hence largely immune to jamming. Passive systems that also use ‘illuminators of opportunity’ do not have to provide a potentially expensive transmitter. Multiple transm...

Ronald Mahler’s Probability Hypothesis Density (PHD) provides a promising framework for the passive coherent location of targets observed via multiple bistatic radar measurements. We consider tracking targets using only range measurements from a simple non-directional receiver that exploits non-cooperative FM radio transmitters as its “illuminators of opportunity.” A target cannot be located at...

Strong fluorescent Fe line emission at 6.4 keV has been observed from the Sgr B2 giant molecular cloud located in the Galactic Center region. The large equivalent width of this line and the lack of an apparent illuminating nearby object indicate that a time-dependent source, currently in a low-activity state, is causing the fluorescent emission. It has been suggested that this illuminator is th...