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The principle and performance of Synthetic Impulse and Antenna Radar(SIAR) are analyzed with the concept of 3D matched filtering. The discussion here is concentrated on the characteristics of SIAR in the case of three dimensions....
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The principle and performance of Synthetic Impulse and Antenna Radar(SIAR) are analyzed with the concept of 3D matched filtering. The discussion here is concentrated on the characteristics of SIAR in the case of three dimensions. The results obtained are helpful for designing this new style radar.
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The design and development of a wideband dual polarized planar array antenna of 3 ×6 elements in C band is presented. The center frequency is 5.3 GHz. The single radiating element used in the array configuration is of stacked SSF...
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The design and development of a wideband dual polarized planar array antenna of 3 ×6 elements in C band is presented. The center frequency is 5.3 GHz. The single radiating element used in the array configuration is of stacked SSFIP. The antenna has been developed for beam pointing of 100 and side-lobe level better than -15 dB by proper choice of the complex excitation coefficients. The array antenna offers a bandwidth of 20% for a VSWR ratio of 2:1. The measured S parameters and radiation patterns are presented.
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This article presents a novel broadband circularly polarized microstrip array antenna for synthetic aperture radar system onboard Cessna 172 Aircraft. The antenna employs an $8\times 8$ matrix formation with uniform element sepa...
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This article presents a novel broadband circularly polarized microstrip array antenna for synthetic aperture radar system onboard Cessna 172 Aircraft. The antenna employs an $8\times 8$ matrix formation with uniform element separation of $0.5\lambda $ and single-proximity-coupled strip-line feeding. The circular polarization wave generation uses a curved-truncation patch and a circle-slotted parasitic patch above it to realize the broadband circularly polarized antenna. The broadening of the axial ratio bandwidth (ARBW) applies a fully serial sequential rotation on the array feeding network. Meanwhile, the gain is improved using a circle-slotted parasitic patch with a floating cover on the top layer. The prototype antenna has a physical aperture of 270 mm $\times $ 300 mm with 1.1-kg weight. The prototype produces an impedance bandwidth of 1.5 GHz (29.3%), ARBW of 1.62 GHz (30.6%), a gain of 18.17 dBic, and aperture efficiency of 26%. The azimuth and elevation beamwidth achieved 12.7° and 13.0° at the center frequency, respectively.
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In the bistatic synthetic aperture radar (SAR), the comodulation effect induced by transmitting and receiving antennas to the image amplitude is the main factor affecting the radiometric accuracy. Therefore, the corresponding mech...
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In the bistatic synthetic aperture radar (SAR), the comodulation effect induced by transmitting and receiving antennas to the image amplitude is the main factor affecting the radiometric accuracy. Therefore, the corresponding mechanism must be determined, and a correction method must be developed. However, there is no effective calibration target and method for measuring the bistatic SAR range round trip antenna pattern. In this letter, it is pointed out that the comodulation effect is not only related to the transmitting and receiving one-way antenna patterns but also to the range variation of the bistatic angle in the swath caused by the bistatic SAR observation geometry. To increase the radiometric accuracy in bistatic SAR images, a comodulation effect correction method based on accurate antenna models is proposed, and different error factors related to the range round trip antenna pattern are analyzed. Moreover, simulation experiments are conducted to verify the effectiveness of the proposed method.
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In this paper, after a brief review on the working principles of synthetic aperture radiometers exploiting interferometry and mechanical rotation of the antenna, analytical expressions are provided which allow to easily compute th...
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In this paper, after a brief review on the working principles of synthetic aperture radiometers exploiting interferometry and mechanical rotation of the antenna, analytical expressions are provided which allow to easily compute the receiving performance of the interferometer starting from given locations of its sensors. Then, an innovative and general approach is developed and discussed for the optimal synthesis of the locations of the array sensors in order to fulfill requirements of crucial interest. Moreover, an innovative approach is also developed for the synthesis of the optimal weighting of the different collected signals. Finally, the performances of the developed synthesis approaches are discussed with reference to the GEO Atmospheric Sounder (GAS) array instrument.
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This paper presents the integration and channel characterization of a highly integrated dual-band digital beamforming space-borne synthetic aperture radar (SAR) receiver. The proposed SAR sensor is a low-cost, lightweight, low-pow...
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This paper presents the integration and channel characterization of a highly integrated dual-band digital beamforming space-borne synthetic aperture radar (SAR) receiver. The proposed SAR sensor is a low-cost, lightweight, low-power consumption, and dual-band (X/Ka) dual-polarized module ready for the next-generation space-borne SAR missions. In previous works, by the authors, the design and experimental characterization of each sub-system was already presented and discussed. This work expands upon the previous characterization by providing an exhaustive experimental assessment of the fully integrated system. As it will be shown, the proposed tests were used to validate all the instrument channels in a set-up where the SAR sensor was illuminated by an external source minim the ground reflected waves. Test results demonstrate how the system channels are properly operating allowing the reception of the input signals and their processing in the digital domain. The possibility to easily implement a calibration procedure has also been validated to equalize, in the digital domain, the unavoidable amplitude differences between the different channels.
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Ground penetrating radar (GPR) systems on board unmanned aerial vehicles (UAVs) have been successfully used for subsurface imaging applications. Their capability to detect buried targets avoiding the contact with the soil turn the...
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Ground penetrating radar (GPR) systems on board unmanned aerial vehicles (UAVs) have been successfully used for subsurface imaging applications. Their capability to detect buried targets avoiding the contact with the soil turn these systems into a great solution to detect buried threats, such as landmines and improvised explosive devices. Significant advances have been also conducted to enhance the detection capabilities of these systems, complementing the synthetic aperture radar (SAR) processing methods with several clutter mitigation techniques. However, the improvement in the scanning throughput (i.e., increasing the inspected area in a given time) remains a significant challenge. In this regard, this article compares several scanning strategies for UAV-mounted multichannel GPR-SAR systems using antenna arrays. In particular, two different scanning strategies have been compared: a uniform scheme and a nonuniform strategy called 3
X
. In addition, different across-track spacing values to generate dense and sparse sampling distributions were considered for each scanning scheme. After conducting a theoretical analysis of these strategies, they have been experimentally validated with measurements gathered with a portable scanner and during flights in realistic scenarios. Results show that the dense configurations of both scanning strategies yield good quality images of buried targets while improving the scanning throughput (compared to a single-channel architecture). In particular, the dense uniform scheme (with a 20-cm across-track spacing) achieves a greater reduction in the inspection time, compared to the dense 3
X
strategy, at the expense of a slightly smaller signal to clutter ratio.
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A high-priority next-generation satellite remote sensing mission necessitates a lightweight deployable antenna that can fit in the package of low-Earth orbit (LEO) small satellites. In this work, we present the development of a 7 ...
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A high-priority next-generation satellite remote sensing mission necessitates a lightweight deployable antenna that can fit in the package of low-Earth orbit (LEO) small satellites. In this work, we present the development of a 7 m
$\times1.5$
m aperture C-band parabolic cylinder mesh reflector along with a 1 × 32 element linear patch array feed. The detailed and tailored mechanical design, full-wave analysis, and measurements of the reflector are elaborated. The reflector is constructed with a mesh surface with unique deployment mechanisms for weight reduction and stowage. The linear microstrip patch array feed is designed with a lightweight honeycomb substrate and is used for the breadboard testing of the parabolic cylinder reflector. The antenna achieved the desired surface accuracy and a measured gain of 42.06 dBi at 5.357 GHz, with half-power beamwidths of 0.52° and 2.35° in the two principal planes.
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As part of the European Space Agency (ESA) studies of new instrument for Earth observation, the design of a synthetic aperture radar (SAR) architecture based on overlapped array antennas was launched last year. The objective of th...
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As part of the European Space Agency (ESA) studies of new instrument for Earth observation, the design of a synthetic aperture radar (SAR) architecture based on overlapped array antennas was launched last year. The objective of the activity is to develop a test unit of a reflector based SAR antenna fed by an array organized in overlapped subarrays, supporting novel multichannel wide-swath SAR architectures, and exploiting multiple beams in both azimuth and range/elevation directions. In the letter, a hybrid analog/digital beamforming on reception with analog beamforming approach on transmission is analyzed. The antenna system consists of a large oversize reflector with a feedarray capable of generating multiple beams on receive for digital processing. In the letter, a description of the hybrid SAR Instrument is presented, describing the characteristics of the system, the antenna, the considered feedarray options and the main characteristics and system performances.
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A C-band four-frequency resonant stacked-patch array antenna is developed for synthetic thinned aperture radiometer measurements of hurricane force wind speeds. This antenna is being integrated into an aircraft instrument referred...
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A C-band four-frequency resonant stacked-patch array antenna is developed for synthetic thinned aperture radiometer measurements of hurricane force wind speeds. This antenna is being integrated into an aircraft instrument referred to as the Hurricane Imaging Radiometer (HIRAD). Details of the antenna design are presented along with antenna performance tests and laboratory measurements using a full-scale prototype array with a subset model of the HIRAD instrument.
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