On SAR processing using pixel-wise matched kernels

Jylhä, Juha; Väilä, Minna; Perälä, Henna; Vaisanen, Ville; Visa, Ari; Vehmas, Risto; Kylmala, Jarkko; Salminen, Vesa-Jukka

doi:10.1109/eurad.2014.6991216

Cited by 4 publications

(1 citation statement)

References 9 publications

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“…Mathematically, the SAR processing can be implemented as

where

is the complex sample at the frequency n of the VNA measurement from the aperture position m ,

is an amplitude compensation factor due to free space propagation, and

is the position of the radar along the track. SAR image reconstruction using ( 7 ) is equivalent to performing a matched filter for each image pixel [ 19 ]. Although evaluating ( 7 ) is computationally intensive, we avoid introducing any approximations to speed up the computation: reconstruction accuracy is more important than real-time processing.…”

Section: Sar Signal Processingmentioning

confidence: 99%

SodSAR: A Tower-Based 1–10 GHz SAR System for Snow, Soil and Vegetation Studies

Ruiz

Vehmas

Lemmetyinen

et al. 2020

Sensors

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We introduce SodSAR, a fully polarimetric tower-based wide frequency (1–10 GHz) range Synthetic Aperture Radar (SAR) aimed at snow, soil and vegetation studies. The instrument is located in the Arctic Space Centre of the Finnish Meteorological Institute in Sodankylä, Finland. The system is based on a Vector Network Analyzer (VNA)-operated scatterometer mounted on a rail allowing the formation of SAR images, including interferometric pairs separated by a temporal baseline. We present the description of the radar, the applied SAR focusing technique, the radar calibration and measurement stability analysis. Measured stability of the backscattering intensity over a three-month period was observed to be better than 0.5 dB, when measuring a target with a known radar cross section. Deviations of the estimated target range were in the order of a few cm over the same period, indicating also good stability of the measured phase. Interforometric SAR (InSAR) capabilities are also discussed, and as a example, the coherence of subsequent SAR acquisitions over the observed boreal forest stand are analyzed over increasing temporal baselines. The analysis shows good conservation of coherence in particular at L-band, while higher frequencies are susceptible to loss of coherence in particular for dense vegetation. The potential of the instrument for satellite calibration and validation activities is also discussed.

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“…Mathematically, the SAR processing can be implemented as

where

is the complex sample at the frequency n of the VNA measurement from the aperture position m ,

is an amplitude compensation factor due to free space propagation, and

Section: Sar Signal Processingmentioning

confidence: 99%

SodSAR: A Tower-Based 1–10 GHz SAR System for Snow, Soil and Vegetation Studies

Ruiz

Vehmas

Lemmetyinen

et al. 2020

Sensors

Self Cite

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Inverse Synthetic Aperture Radar Imaging: A Historical Perspective and State-of-the-Art Survey

Vehmas¹,

Neuberger

2021

IEEE Access

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Radar can obtain high spatial resolution at large operating distances and its operation is largely independent from weather and lighting conditions. This makes it an important instrument in an ever-increasing number of applications requiring robust and reliable sensing of the environment. Due to the advancements in semiconductor technology and digital computation power, radar can obtain increasingly better position estimation accuracy, detection sensitivity, and target resolution. High-resolution imaging is an example of a rapidly advancing field of radar technology. Inverse synthetic aperture radar (ISAR) is an imaging technique that uses the motion of a target to obtain a high-resolution radar image of it. This paper presents a comprehensive review of past work and the state-of-the-art in ISAR imaging systems, algorithms, and applications. Starting from the early historical developments of simple monostatic range-Doppler imaging, we present the developments up to the current advanced spatially distributed imaging modalities and reconstruction algorithms. The list of references includes the most influential ISAR publications in the open literature up to early 2021.

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