The Multi-Chromatic Analysis, as introduced in [1], uses interferometric pairs of SAR images processed at range sub-bands and explores the phase trend of each pixel as a function of the different central carrier frequencies. The phase of stable scatterers evolves linearly with the sub-band central wavelength, the slope being proportional to the absolute optical path difference. Unlike the standard "monochromatic" InSAR approach, this technique allows performing spatially independent and absolute topographic measurements, if the attention is focused on single targets exhibiting stable phase behaviour across the frequency domain. Potential applications for the study of frequency-stable targets include topographic measurement, atmospheric research, and urban monitoring. Through a simplified model [2], we obtained a first evaluation of the impact of the MCA processing parameters on the height estimation performances. A total bandwidth of at least 300 MHz seems to be required to provide reliable results. Thus, the technique appears optimally suited for the new generation of satellite sensors, which operate with larger bandwidths than previously available instruments, generally limited to few tens of MHz. SAR sensors such as those mounted on TerraSAR-X (TSX) or COSMO-SkyMed (CSK) spacecraft, all pose great expectations on the potential use of multi-chromatic methods. The practical feasibility of the technique was demonstrated in [2] by using a set of SAR data collected by the airborne AES-1 radar interferometer, operating at X-band by multi-channel electronics, which provides a total radar bandwidth of 400 MHz. A first successful application of the technique to satellite data was also shown in [3] by using a spotlight interferometric pair of images acquired by TSX on the well-known Uluru monolith in Australia. In the present work, we illustrate results obtained through MCA processing on spaceborne SAR data acquired by the CSK constellation both on Parkfield in California (USA), and on the Uuluru monolith. A CSK tandem pair acquired on the Uluru test site was used to validate the MCA-based height measurements by using a digital surface model (DSM) derived from optical stereo imagery captured at 15 cm resolution. The same dataset was also processed to validate the theoretical analysis [2] developed to assess the performance of the MCA with respect to the radiometric parameters involved in the processing (total bandwidth, sub-bandwidth, number of sub bands). The MCA technique introduces the concept of frequency-stable targets (PSfd), i.e. objects exhibiting stable radar returns across the frequency domain. This concept is complementary to that of temporal stability, which is at the base of persistent scatterers interferometry (PSI) techniques [4]. In PSI applications, stable targets (PS) are recognized as those exhibiting temporal stability through a stack of tens of SAR images. It is then natural to try to compare the two concepts, examining the assumptions which form the basis of the two definitions, and evaluating the respective characteristics of the two populations, with the final goal of ascertaining if any synergy can be identified between the two types of object. The Parkfield test site was used to attempt this comparison. A stack of 33 spotlight CSK acquisition was used to perform PSI through the SPINUA PSI algorithm [5]. Four tandem pairs selected within the multitemporal dataset were processed through MCA in order to derive four sets of PSfd to compare to the PS targets. An ad hoc processing scheme was developed to derive PSI products by processing the same range sub-bandwidth used by the MCA in order to guarantee the same scattering conditions. The populations of PSfd and "temporal" PS were compared and preliminary considerations provided concerning the scattering properties of the targets selected by the two criteria. Finally, we present potentials of MCA to measure absolute ranging by using a single SAR image. References [1]N. Veneziani, F. Bovenga, A. Refice, "A wide-band approach to absolute phase retrieval in SAR interferometry", Multidimensional Systems and Signal Processing, Vol. 14(1-2), pp. 183-205, 2003. [2]F. Bovenga, V. M. Giacovazzo, A. Refice, N. Veneziani, R. Vitulli, "Multi-Chromatic Analysis of InSAR data: validation and potential", Proceedings of FRINGE 2009, ESA-ESRIN, Frascati, Italy, Nov.30 - Dec. 4, 2009. [3]F. Bovenga, V. M. Giacovazzo, A. Refice, D. O. Nitti, N. Veneziani, "Interferometric multi-chromatic analysis of high resolution X-band data". Proceedings of FRINGE 2011, ESA-ESRIN, Frascati, Italy, Sept. 19-23, 2011. [4]A. Ferretti, C. Prati, and F. Rocca, "Permanent Scatterers in SAR Interferometry", IEEE Trans. Geosc. Remote Sens., vol. 39(1), pp. 8-20, 2001. [5]F. Bovenga, A. Refice, R. Nutricato, L. Guerriero, and M. T. Chiaradia, "SPINUA: a flexible processing chain for ERS/ENVISAT long term interferometry," in Proc. 2004 Envisat & ERS Symposium, Salzburg, Austria, 6-10 September, 2004.
Multi-chromatic analysis of high resolution X-band SAR data
F Bovenga;FM Rana;A Refice;N Veneziani
2012
Abstract
The Multi-Chromatic Analysis, as introduced in [1], uses interferometric pairs of SAR images processed at range sub-bands and explores the phase trend of each pixel as a function of the different central carrier frequencies. The phase of stable scatterers evolves linearly with the sub-band central wavelength, the slope being proportional to the absolute optical path difference. Unlike the standard "monochromatic" InSAR approach, this technique allows performing spatially independent and absolute topographic measurements, if the attention is focused on single targets exhibiting stable phase behaviour across the frequency domain. Potential applications for the study of frequency-stable targets include topographic measurement, atmospheric research, and urban monitoring. Through a simplified model [2], we obtained a first evaluation of the impact of the MCA processing parameters on the height estimation performances. A total bandwidth of at least 300 MHz seems to be required to provide reliable results. Thus, the technique appears optimally suited for the new generation of satellite sensors, which operate with larger bandwidths than previously available instruments, generally limited to few tens of MHz. SAR sensors such as those mounted on TerraSAR-X (TSX) or COSMO-SkyMed (CSK) spacecraft, all pose great expectations on the potential use of multi-chromatic methods. The practical feasibility of the technique was demonstrated in [2] by using a set of SAR data collected by the airborne AES-1 radar interferometer, operating at X-band by multi-channel electronics, which provides a total radar bandwidth of 400 MHz. A first successful application of the technique to satellite data was also shown in [3] by using a spotlight interferometric pair of images acquired by TSX on the well-known Uluru monolith in Australia. In the present work, we illustrate results obtained through MCA processing on spaceborne SAR data acquired by the CSK constellation both on Parkfield in California (USA), and on the Uuluru monolith. A CSK tandem pair acquired on the Uluru test site was used to validate the MCA-based height measurements by using a digital surface model (DSM) derived from optical stereo imagery captured at 15 cm resolution. The same dataset was also processed to validate the theoretical analysis [2] developed to assess the performance of the MCA with respect to the radiometric parameters involved in the processing (total bandwidth, sub-bandwidth, number of sub bands). The MCA technique introduces the concept of frequency-stable targets (PSfd), i.e. objects exhibiting stable radar returns across the frequency domain. This concept is complementary to that of temporal stability, which is at the base of persistent scatterers interferometry (PSI) techniques [4]. In PSI applications, stable targets (PS) are recognized as those exhibiting temporal stability through a stack of tens of SAR images. It is then natural to try to compare the two concepts, examining the assumptions which form the basis of the two definitions, and evaluating the respective characteristics of the two populations, with the final goal of ascertaining if any synergy can be identified between the two types of object. The Parkfield test site was used to attempt this comparison. A stack of 33 spotlight CSK acquisition was used to perform PSI through the SPINUA PSI algorithm [5]. Four tandem pairs selected within the multitemporal dataset were processed through MCA in order to derive four sets of PSfd to compare to the PS targets. An ad hoc processing scheme was developed to derive PSI products by processing the same range sub-bandwidth used by the MCA in order to guarantee the same scattering conditions. The populations of PSfd and "temporal" PS were compared and preliminary considerations provided concerning the scattering properties of the targets selected by the two criteria. Finally, we present potentials of MCA to measure absolute ranging by using a single SAR image. References [1]N. Veneziani, F. Bovenga, A. Refice, "A wide-band approach to absolute phase retrieval in SAR interferometry", Multidimensional Systems and Signal Processing, Vol. 14(1-2), pp. 183-205, 2003. [2]F. Bovenga, V. M. Giacovazzo, A. Refice, N. Veneziani, R. Vitulli, "Multi-Chromatic Analysis of InSAR data: validation and potential", Proceedings of FRINGE 2009, ESA-ESRIN, Frascati, Italy, Nov.30 - Dec. 4, 2009. [3]F. Bovenga, V. M. Giacovazzo, A. Refice, D. O. Nitti, N. Veneziani, "Interferometric multi-chromatic analysis of high resolution X-band data". Proceedings of FRINGE 2011, ESA-ESRIN, Frascati, Italy, Sept. 19-23, 2011. [4]A. Ferretti, C. Prati, and F. Rocca, "Permanent Scatterers in SAR Interferometry", IEEE Trans. Geosc. Remote Sens., vol. 39(1), pp. 8-20, 2001. [5]F. Bovenga, A. Refice, R. Nutricato, L. Guerriero, and M. T. Chiaradia, "SPINUA: a flexible processing chain for ERS/ENVISAT long term interferometry," in Proc. 2004 Envisat & ERS Symposium, Salzburg, Austria, 6-10 September, 2004.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
