Processing of SAR Data

Hein, Achim

doi:10.1007/978-3-662-09457-0

Cited by 27 publications

(4 citation statements)

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“…Microwave wavelengths allow imaging of the land surface through cloud cover, and with SAR being an active system, images can also be gathered at night. Airborne or space-borne SAR systems follow a side-looking design that uses the Doppler effect of relative motion between the antenna and its target to provide distinctive long-term coherent signal variations to generate much higher resolution imagery than would be possible from a real aperture radar [74].…”

Section: Microwavementioning

confidence: 99%

Quantifying Forest Biomass Carbon Stocks From Space

et al. 2017

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Purpose of Review This review presents cutting-edge methods and current and forthcoming satellite remote sensing technologies to map aboveground biomass (AGB). Recent Findings The monitoring of carbon stored in living AGB of forest is of key importance to understand the global carbon cycle and for the functioning of international economic mechanisms aiming to protect and enhance forest carbon stocks. The main challenge of monitoring AGB lies in the difficulty of obtaining field measurements and allometric models in several parts of the world due to geographical remoteness, lack of capacity, data paucity or armed conflicts. Space-borne remote sensing in combination with ground measurements is the most cost-efficient technology to undertake the monitoring of AGB. Summary These approaches face several challenges: lack of ground data for calibration/validation purposes, signal saturation in high AGB, coverage of the sensor, cloud cover persistence or complex signal retrieval due to topography. New space-borne sensors to be launched in the coming years will allow accurate measurements of AGB in high biomass forests (>200 t ha −1 ) for the first time across large areas.

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Section: Microwavementioning

confidence: 99%

Quantifying Forest Biomass Carbon Stocks From Space

et al. 2017

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“…However, this reduces the overall duty cycle and limits the available power of the transmitted signal. To cope with this problem, modern SAR systems use "chirp" signals, which offers a higher bandwidth, and thus range resolution, independent of the pulse duration [12]. A single pulse of a typical SAR signal with center frequency f 0 , pulse duration T p , and sweep rate k can be represented as…”

Section: Sar Signal Characteristicsmentioning

confidence: 99%

GNSS Interference in L-Band SAR Missions � Assessment and Mitigation

Montenbruck¹,

Markgraf²,

Tossaint³

2019

The International Technical Meeting of the the Institute of Navigation

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Synthetic Aperture Radar (SAR) satellites commonly make use of onboard Global Positioning System (GPS) receivers for precise orbit and baseline determination. In view of the extreme SAR transmit power levels, interference from SAR signals may inhibit proper GPS tracking and poses a particular challenge to space missions using L-band SAR signals with frequencies adjacent to or even overlapping GPS frequency bands. Within this study, the impact of simulated SAR signals on direct and semi-codeless GPS signal tracking is assessed in a signal simulator test bed using two commercial-off-the-shelf geodetic-grade receivers. A high robustness of GPS tracking to both adjacent-band and in-band SAR interference is obtained within the tests using representative chirp signals. For SAR signals next to or overlapping the GPS L2 band, proper tracking of the GPS L1 C/A code, GPS2 L2C, and semi-codeless L1/L2 P(Y)-code tracking is retained for interference powers up to 90 db above the natural GPS signal power. Apparently, a high level of immunity to high-power pulsed signals with repeat periods in the (sub-)ms regime is already provided by the automatic gain control of the receivers and/or a saturation of the analog-to-digital converters in the frontend that mimic an explicit pulse blanking. On the other hand, the addition of an external pulse blanking synchronized with the chirp pulses was found to be of marginal value. This unexpected results can presumably be understood by low power "noise" in the synthetic SAR signals that adds an additional signal outside the spectral and temporal limitations of the actual chirp signal and dominates the overall interference when simulating very high chirp signal powers.

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“…This Doppler information is embedded in the phase, which has to be properly processed to obtain a higher resolution image, which turns out to be independent of the range and proportional to the antenna aperture. Measurements are usually arranged in two-dimensional arrays, matrices, that contain the sampled echoes of the signals emitted at a fixed point in space in columns while rows correspond to sampled echoes taken at other points in space [4,9]. SAR signal memory is shown in Fig.…”

Section: Introductionmentioning

confidence: 99%

“…There are several known algorithms for SAR image focusing, range Doppler algorithm (RDA), chirp scaling algorithm (CSA), ω-k algorithm, back-projection algorithm and others [4,9,20]. Since linearity is assumed in most of these models, the vast majority use both frequency and spatial coordinates in the processing stages.…”

Section: Introductionmentioning

confidence: 99%

Synthetic aperture radar signal processing in parallel using GPGPU

2015

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In this work an efficient parallel implementation of the Chirp Scaling Algorithm for Synthetic Aperture Radar processing is presented. The architecture selected for the implementation is the general purpose graphic processing unit, as it is well suited for scientific applications and real-time implementation of algorithms. The analysis of a first implementation led to several improvements which resulted in an important speed-up. Details of the issues found are explained, and the performance improvement of their correction explicitly shown.

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Processing of SAR Data

Abstract: The use of general descriptive names, registered names trademarks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use.

Cited by 27 publications

References 0 publications

Quantifying Forest Biomass Carbon Stocks From Space

Quantifying Forest Biomass Carbon Stocks From Space

GNSS Interference in L-Band SAR Missions � Assessment and Mitigation

Synthetic aperture radar signal processing in parallel using GPGPU

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