On-board encoding of the ENVISAT wave mode data

McLeod, I.H.; Cumming, I.

doi:10.1109/igarss.1995.523995

Cited by 10 publications

(4 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A popular evolution of BAQ is the Flexible Block Adaptive Quantizer (FBAQ), used in many mission [5].The goal of FBAQ is to maintain the simple quantization approach of BAQ, allowing for three different compression ratios, namely 2, 3, or 4 bits/sample. The main practical difference lies in the number of threshold comparisons required for each input sample.…”

Section: Flexible Block Adaptive Quantizermentioning

confidence: 99%

“…The implementation on a rad tolerant DSP permits to achieve high efficiency levels exploiting parallelization at the instruction and possibly board level. Classical SAR raw data compression is based on BAQ (Block Adaptive Quantizer) [3], that yields a fixed compression ratio, or its flexible version FBAQ [5] . This latter is a non-uniform quantizer, in which compression is performed comparing the input samples with proper thresholds.…”

mentioning

confidence: 99%

See 1 more Smart Citation

<title>Efficient DSP implementation of a new SAR raw-data compression algorithm</title>

Cordara

Laia

Grangetto

et al. 2002

Earth Observing Systems VI

View full text Add to dashboard Cite

Modern SAR sensors exhibit data rates of the order of hundreds Mbit/s; as a consequence, on board data compression is mandatory. The compression algorithms must be characterized by high computational efficiency and satisfactory compression ratios; on the other hand, losses must be kept within limits that take into account the interpretability of the decompressed data.The compressor presented in this paper is flexible, and allows for compression on 2, 3 or 4 bit/sample, useful respectively for topographic monitoring and interferometric applications. The implementation on a rad tolerant DSP permits to achieve high efficiency levels exploiting parallelization at the instruction and possibly board level. Classical SAR raw data compression is based on BAQ (Block Adaptive Quantizer) [3], that yields a fixed compression ratio, or its flexible version FBAQ [5] . This latter is a non-uniform quantizer, in which compression is performed comparing the input samples with proper thresholds. The achievable throughput is limited by the need for multiple comparisons for each data sample. For this reason, a variant of FBAQ is presented, based on the key idea of transforming the input samples so that they exhibit uniform distribution; this feature makes possible to perform the compression via simple truncation. The algorithm has been implemented and optimized from the point of view of the achievable throughput.With respect to FBAQ, it exhibits larger memory requirements (16384 extra words of 32-bit), but significantly improved processing speed without appreciable performance degradation in terms of SQNR and phase error.For example, in the case of 4 bit/sample, a throughput 40% larger than FBAQ can be achieved. The algorithm, implemented on high-frequency, radiation tolerant DSPs, will be able to match the requirements of modern SAR for most practical applications.

show abstract

Section: Flexible Block Adaptive Quantizermentioning

confidence: 99%

mentioning

confidence: 99%

<title>Efficient DSP implementation of a new SAR raw-data compression algorithm</title>

Cordara

Laia

Grangetto

et al. 2002

Earth Observing Systems VI

View full text Add to dashboard Cite

show abstract

“…The first is Sardinia, Italy, consisting of ERS-1 data acquisitions taken six days apart during orbits 241 (Aug. 2, 1991) and 327 (Aug. 8,1991). The second pair is Toolik Lake, Alaska, from orbits 943 (Sept. 20, 1991) and 1029 (Sept. 26, 1991).…”

Section: A Scene Selectionmentioning

confidence: 99%

“…The ASIC was implemented by Saab-Ericsson Space in 1994. However, while the quality of SAR images produced using the algorithm were evaluated with good results, it was also considered important to examine the impact of data encoding on selected applications, such as ocean wave analysis (wavemode) [8] and repeat-pass interferometry [9].…”

Section: Introductionmentioning

confidence: 99%

ENVISAT ASAR data reduction: impact on SAR interferometry

McLeod

Cumming

Seymour

1998

IEEE Trans. Geosci. Remote Sensing

Self Cite

View full text Add to dashboard Cite

Abstract-An onboard synthetic aperture radar (SAR) signaldata reduction algorithm called Flexible Block Adaptive Quantization (FBAQ) was developed in 1994 for the Advanced SAR (ASAR) on the ENVISAT satellite. This paper presents work done in a follow-on study that examined the impact of the datareduction algorithm on the accuracy of two digital elevation models (DEM) produced by using the technique of repeat-pass SAR interferometry. All three allowable data compression ratios were investigated to determine the maximum compression ratio appropriate for SAR interferometry. Based on the scenes studied in this paper, it was concluded that a reduction from 8 to 4-bits/sample was the maximum data reduction ratio appropriate for precision SAR interferometry, while 8 to 3-bits/sample and 8 to 2-bits/sample encoding were only appropriate for lessdemanding wide-swath applications.Index Terms-Block adaptive quantization, data compression, satellite interferometry.

show abstract