Multistatic three-dimensional syntheticapertureradar (3D SAR) has shown significant potential in rapid 3D imaging. Compared to traditional multi-pass or array 3D imaging systems, it achieves high-resolution imaging ...
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SARLink is a passive satellite backscatter communication system that uses existing spaceborne syntheticapertureradar (SAR) imaging satellites to provide connectivity in remote regions. It achieves orders of magnitud...
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ISBN:
(纸本)9798400714795
SARLink is a passive satellite backscatter communication system that uses existing spaceborne syntheticapertureradar (SAR) imaging satellites to provide connectivity in remote regions. It achieves orders of magnitude more range than traditional backscatter systems, enabling communication between a passive ground node and a satellite in low earth orbit. The system is composed of a cooperative ground target, a SAR satellite, and a data processing algorithm. A mechanically modulating reflector was designed to apply amplitude modulation to ambient SAR backscatter signals by changing its radar cross section. These communication bits are extracted from the raw SAR data using an algorithm that leverages subapertureprocessing to detect multiple bits from a target in a single image dataset. A theoretical analysis of this communication system using on-off keying is presented, including the expected signal model, throughput, and bit error rate. The results suggest a 5.5 ft by 5.5 ft modulating corner reflector could send 60 bits every satellite pass, enough to support low bandwidth sensor data and messages. Using Sentinel-1A, a SAR satellite at an altitude of 693 km, we deployed static and modulating reflectors to evaluate the system. The results, successfully detecting the changing state of a modulating ground target, demonstrate our algorithm's effectiveness for extracting bits, paving the way for ultra-long-range, low-power satellite backscatter communication.
If wide-range swath scenes are illuminated by a syntheticapertureradar with high-pulse repetition frequencies, ambiguous scattered signals from an undesired range may appear in its receiver at the same time from con...
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If wide-range swath scenes are illuminated by a syntheticapertureradar with high-pulse repetition frequencies, ambiguous scattered signals from an undesired range may appear in its receiver at the same time from consecutive transmitted pulses. This simplified analysis shows that range ambiguous signal returns result in a defocused image because they are convolved with the phase history of the desired range signal. A satellite borne SAR example is presented.
This paper evaluates and compares the performance of various image denoising techniques, including wavelet transform, Wiener filtering, non-local means (NLM), denoising autoencoders (DAEs), and feedforward autoencoder...
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ISBN:
(数字)9798331518752
ISBN:
(纸本)9798331518769
This paper evaluates and compares the performance of various image denoising techniques, including wavelet transform, Wiener filtering, non-local means (NLM), denoising autoencoders (DAEs), and feedforward autoencoders. There are cases of additive and multiplicative noises considered where the Gaussian distribution with zero mean stands for the first case and an exponential distribution with unity mean describes the second case (speckle). The experiments have been conducted on the given dataset which contained both still test images and syntheticapertureradar (SAR) images with varying noise levels to analyze the effectiveness of these denoising approaches. The performance of each method is assessed using key image quality metrics: Peak signal-to-Noise Ratio (PSNR), Structural Similarity Index (SSIM), Mean Squared Error (MSE), and Normalized Absolute Error (NAK). The results demonstrate that denoising autoencoders DAEs provide superior performance in terms of structural preservation and noise reduction, particularly in low-noise conditions, while Wiener filtering proves to be computationally efficient and robust under high-noise conditions. These findings offer insights into the selection of effective denoising techniques for noisy images based on specific noise characteristics and application requirements.
This letter closes a special stream consisting of selected papers from the fifth Asia-Pacific conference on syntheticapertureradar in 2015 (APSAR 2015). The latest research results and outcomes from APSAR 2015, part...
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This letter closes a special stream consisting of selected papers from the fifth Asia-Pacific conference on syntheticapertureradar in 2015 (APSAR 2015). The latest research results and outcomes from APSAR 2015, particularly on the syntheticapertureradar (SAR) systems/subsystems design, data processing techniques, and various SAR applications in remotesensing, are summarized and presented. All these results represent the recent advances in SAR remotesensing. Hopefully, this letter can provide some references for SAR researchers/engineers and stimulate the future development of SAR technology for remotesensing.
This paper introduces a task named Visual Grounding of remotesensing Ship images (VGRSS). The goal of VGRSS is to locate ship objects in remotesensingimages guided by natural language. Extensive research has been c...
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When it comes to deep learning-based methods for despeckling syntheticapertureradar (SAR) images, maintaining spatial structure, ensuring process stability as well as achieving fast inference are still major challen...
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The subject of this work is the detection and high resolution microwave imaging of objects moving on the ground and observed by an airborne radar. The proposed approach is based on a combined space-time and time-frequ...
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The subject of this work is the detection and high resolution microwave imaging of objects moving on the ground and observed by an airborne radar. The proposed approach is based on a combined space-time and time-frequency processing. The space-time processing makes use of a linear array antenna and exploits the radar motion for filtering the received echoes in order to improve as much as possible the signal-to-disturbance ratio. The signal is then mapped onto the time-frequency domain, by computing its Wigner-Ville distribution, for a further filtering and for estimating its instantaneous frequency, necessary for the formation of a high resolution image of the moving object.
As a powerful all-weather Earth observation tool, syntheticapertureradar (SAR) remotesensing enables critical military reconnaissance, maritime surveillance, and infrastructure monitoring. Although Vision language ...
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The proceedings contain 19 papers. The topics discussed include: laser long-path absorption experiment using retroreflector in space (RIS) on the ADEOS satellite;time walk compensated SPAD: multiple photons versus sin...
The proceedings contain 19 papers. The topics discussed include: laser long-path absorption experiment using retroreflector in space (RIS) on the ADEOS satellite;time walk compensated SPAD: multiple photons versus single photon operation;two-color SLR experiments at the GSFC 1.2m telescope;space lidar mission concepts for climate studies;some peculiarities in determining the range of the earth's surface with a spaceborne lidar 'Balkan-1' from the space station 'Mir';peculiarities of standardization efforts for lidar measurements;comparison of ERS-2 SAR wind measurements with an airborne Doppler lidar wind measurement;laser ranging and remotesensing;NASDA ELISE (MDS-LIDAR) program;LITE results, performance characteristics, and data archive;the WLRS streak camera experiment;and optical characteristics of the retroreflector in space (RIS) on the ADEOS satellite.
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