Radar

There are several remote-sensing tools readily available for the study of nocturnally flying animals (e.g., migrating birds), each possessing unique measurement biases. We used three tools (weather surveillance radar, thermal infrared camera, and acoustic recorder) to measure temporal and spatial patterns of nocturnal traffic estimates of flying animals during the spring and fall of 2011 and 2012 in Lewes, Delaware, USA. Our objective was to compare measures among different technologies to better understand their animal detection biases. For radar and thermal imaging, the greatest observed traffic rate tended to occur at, or shortly after, evening twilight, whereas for the acoustic recorder, peak bird flight-calling activity was observed just prior to morning twilight. Comparing traffic rates during the night for all seasons, we found that mean nightly correlations between acoustics and the other two tools were weakly correlated (thermal infrared camera and acoustics, r ¼ 0.004 6 0.04 SE, n ¼ 100 nights; radar and acoustics, r ¼ 0.14 6 0.04 SE, n ¼ 101 nights), but highly variable on an individual nightly basis (range ¼ À0.84 to 0.92, range ¼ À0.73 to 0.94). The mean nightly correlations between traffic rates estimated by radar and by thermal infrared camera during the night were more strongly positively correlated (r ¼ 0.39 6 0.04 SE, n ¼ 125 nights), but also were highly variable for individual nights (range ¼ À0.76 to 0.98). Through comparison with radar data among numerous height intervals, we determined that flying animal height above the ground influenced thermal imaging positively and flight call detections negatively. Moreover, thermal imaging detections decreased with the presence of cloud cover and increased with mean ground flight speed of animals, whereas acoustic detections showed no relationship with cloud cover presence but did decrease with increased flight speed. We found sampling methods to be positively correlated when comparing mean nightly traffic rates across nights. The strength of these correlations generally increased throughout the night, peaking 2-3 hours before morning twilight. Given the convergence of measures by different tools at this time, we suggest that researchers consider sampling flight activity in the hours before morning twilight when differences due to detection biases among sampling tools appear to be minimized.

An accurate estimation of a plant's age is required for the prediction of yield and management practices. This study demonstrates the relationship between backscattering properties (σ°) of Phased Array type L-band Synthetic Aperture Radar (PALSAR) dual polarimetric data with cashew plants' biophysical parameters (height, age, crown diameter, diameter at breast height, basal area, tree density, and biomass) in Cambodia. PALSAR σ°has shown a positive correlation with the biophysical parameters of cashew plants. The value of σ°increases with the age of cashew plants. At a young stage, the cashew plants show a higher rate of an increase in σ°compared to that at the mature stage. The σ°horizontal polarization transmitted and vertical received (HV) shows higher sensitivity to the plant's growth than σ°horizontal polarization transmitted and received (HH). High backscattering and low variations were observed at mature stage (8-12 years) of cashew plantation. Saturation in backscattering has shown from the age of about 13 years. The validation results indicate strong coefficient of determination (R 2 00.86 and 0.88) for PALSAR-predicted age and biomass of cashew plants with root mean square error01.8 years and 16.3 t/ha for age and biomass, respectively. The correlations of σ°(HH) with biophysical parameters observed in the dry season were better than those of the rainy season because soil moisture interferes with backscattering in the rainy season. Biomass accumulation rate of cashew plants has been predicted that would be useful for selection of plants species to enhance carbon sequestration. This study provides an insight to use PALSAR for the monitoring of growth stages of plants at the regional level.

This paper presents a generalized structure for a frequency diverse array radar. In its simplest form, the frequency diverse array applies a linear phase progression across the aperture. This linear phase progression induces an electronic beam scan, as in a conventional phased array. When an additional linear frequency shift is applied across the elements, a new term is generated which results in a scan angle that varies with range in the far-field. This provides more flexible beam scan options, as well as providing resistance to point interference such as multipath.

Examining radio development over a long time span from the late nineteenth to the early twenty-first century, in this article, we claim that radio history is broader than the history of broadcasting only. We suggest looking at radio history through the perspective of intermediality and inter-technology, drawing on five different examples: radiography, radiotelegraphy/radiotelephony, radar and satellites, radiomobile/mobile phones with regard to radio spectrum and packet radio networks, such as Wi-Fi. We demonstrate how and why these (and other) technologies should be considered parts of radio studies even though they do not represent classic examples of radio broadcasting. Overall, this intermedia and inter-technological perspective on radio history offers new ways of rethinking and reformulating the confines of radio studies, as well as contributes to a greater field of media studies.

Today in the twenty first century the Missile technology is rapidly developing with the advancement of the science. In today's world all types of missiles uses the principle of combustion for its movement. So, until the new technology initiates the tracking of the missile is possible. These missiles can be tracked with the help of Radar, microwave sensing, etc. These equipment are highly advanced and too costly for every developing country to purchase and implement it for their safety.In order to make its design simple, easy to install and to achieve its efficiency, keeping this in background the project has been designed in such a manner that the Missile is detected using an Ultra-sonic sensor at cheaper cost. This will make the proposed system to be an economical, portable and low maintenance solution for tracking a missile. A plane or a unrecognized object by is sensed by the radar up to a certain limit. The thought achieves the same results by the robotic action automatically for possible application in military and industrial usage.