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Publications (10 of 95) Show all publications
Sievert, T., Rasch, J., Carlström, A. & Pettersson, M. (2018). Analysis of reflections in GNSS radio occultation measurements using the phase matching amplitude. Atmospheric Measurement Techniques, 11, 569-580
Open this publication in new window or tab >>Analysis of reflections in GNSS radio occultation measurements using the phase matching amplitude
2018 (English)In: Atmospheric Measurement Techniques, ISSN 1867-1381, E-ISSN 1867-8548, Vol. 11, p. 569-580Article in journal (Refereed) Published
Abstract [en]

It is well-known that in the presence of super-refractive layers in the lower-tropospheric inversion of GNSSradio occultation (RO) measurements using the Abel trans-form yields biased refractivity profiles. As such it is problem-atic to reconstruct the true refractivity from the RO signal.Additional information about this lower region of the atmo-sphere might be embedded in reflected parts of the signal. Toretrieve the bending angle, the phase matching operator canbe used. This operator produces a complex function of theimpact parameter, and from its phase we can calculate thebending angle. Instead of looking at the phase, in this paperwe focus on the function’s amplitude. The results in this pa-per show that the signatures of surface reflections in GNSSRO measurements can be significantly enhanced when usingthe phase matching method by processing only an appropri-ately selected segment of the received signal. This signatureenhancement is demonstrated by simulations and confirmedwith 10 hand-picked MetOp-A occultations with reflectedcomponents. To validate that these events show signs of re-flections, radio holographic images are generated. Our resultssuggest that the phase matching amplitude carries informa-tion that can improve the interpretation of radio occultationmeasurements in the lower troposphere.

National Category
Remote Sensing Meteorology and Atmospheric Sciences
Identifiers
urn:nbn:se:bth-15843 (URN)10.5194/amt-11-569-2018 (DOI)
Funder
Knowledge Foundation, 20140192Swedish National Space Board, 241/15
Note

open access

Available from: 2018-01-31 Created: 2018-01-31 Last updated: 2018-02-22Bibliographically approved
Vu, V. T. & Pettersson, M. (2018). Derivation of Bistatic SAR Resolution Equations Based on Backprojection. IEEE Geoscience and Remote Sensing Letters
Open this publication in new window or tab >>Derivation of Bistatic SAR Resolution Equations Based on Backprojection
2018 (English)In: IEEE Geoscience and Remote Sensing Letters, ISSN 1545-598X, E-ISSN 1558-0571Article in journal (Refereed) Epub ahead of print
Abstract [en]

This letter introduces ground-range and cross-range resolution equations for the side-looking bistatic synthetic aperture radar (SAR). The derivation is based on the backprojection integral and the method of stationary phase. The ground-range and cross-range resolution equations are provided in closed form, making them easy for calculation. They are, therefore, helpful for bistatic SAR system development. The derived ground-range and cross-range resolution equations are validated with the bistatic data simulated mainly using the parameters of the LORA system. IEEE

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers Inc., 2018
Keyword
Bistatic, resolution equation, stationary phase, synthetic aperture radar (SAR).
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:bth-16025 (URN)10.1109/LGRS.2018.2810314 (DOI)2-s2.0-85043458813 (Scopus ID)
Available from: 2018-03-26 Created: 2018-03-26 Last updated: 2018-03-26Bibliographically approved
Fabrin, A., Molin, R., Alves, D. I., Machado, R., Bayer, F. & Pettersson, M. (2017). A CFAR optimization for low frequency UWB SAR change detection algorithms. In: International Geoscience and Remote Sensing Symposium (IGARSS): . Paper presented at 37th Annual IEEE International Geoscience and Remote Sensing Symposium, IGARSS, Fort Worth (pp. 1071-1074). Institute of Electrical and Electronics Engineers Inc.
Open this publication in new window or tab >>A CFAR optimization for low frequency UWB SAR change detection algorithms
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2017 (English)In: International Geoscience and Remote Sensing Symposium (IGARSS), Institute of Electrical and Electronics Engineers Inc. , 2017, p. 1071-1074Conference paper, Published paper (Refereed)
Abstract [en]

This paper presents a study on the constant false alarm rate (CFAR) filter design for change detection algorithms (CDA). More specifically, we are interested in CFAR filters used in CDA for low frequency ultra-wideband (UWB) synthetic aperture radar (SAR) systems. The filter design performance was evaluated in terms of false alarm rate (FAR) and probability of detection (PD). For evaluation purposes, we considered a set of SAR images obtained with the CARABAS-II system. The results are compared with the ones presented in [1], where the same CDA was considered, except for the CFAR filter. The results show that relevant FAR performance improvements can be obtained by just modifying the CFAR filter parameters taking into account the image resolution and target characteristics. © 2017 IEEE.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers Inc., 2017
Series
IEEE International Symposium on Geoscience and Remote Sensing IGARSS, ISSN 2153-6996
Keyword
CARABAS-II, CDA, CFAR, UWB SAR
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:bth-15925 (URN)10.1109/IGARSS.2017.8127141 (DOI)000426954601057 ()2-s2.0-85041815057 (Scopus ID)9781509049516 (ISBN)
Conference
37th Annual IEEE International Geoscience and Remote Sensing Symposium, IGARSS, Fort Worth
Available from: 2018-02-22 Created: 2018-02-22 Last updated: 2018-04-12Bibliographically approved
Sievert, T., Rasch, J., Anders, C., Pettersson, M. & Vu, V. T. (2017). Determining the refractivity at the bottom of the atmosphere using radio occultation. In: 2017 IEEE International Geoscience and Remote Sensing Symposium (IGARSS): . Paper presented at 2017 IEEE International Geoscience and Remote Sensing Symposium (IGARSS), Fort Worth (pp. 4433-4436). IEEE
Open this publication in new window or tab >>Determining the refractivity at the bottom of the atmosphere using radio occultation
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2017 (English)In: 2017 IEEE International Geoscience and Remote Sensing Symposium (IGARSS), IEEE, 2017, p. 4433-4436Conference paper, Published paper (Refereed)
Abstract [en]

High accuracy of impact height is important to get reliableRadio Occultation (RO) measurements of the atmosphere refractivity.We have made an investigation on how accuratelywe can measure the impact height at ground level using waveoptics simulations, realistic refractivity profiles, a realisticsimulator for an advanced RO instrument including noise,and using phase matching for the inversion. The idea of theinvestigation is to increase the measurement accuracy of impactheight at low altitudes and to give reliable measurementseven in cases of super-refractive layers. We present statisticson the accuracy and precision of the determination of theimpact height at ground, as well as the resulting accuracy andprecision in the measured refractivity.

Place, publisher, year, edition, pages
IEEE, 2017
Series
IEEE International Symposium on Geoscience and Remote Sensing IGARSS, ISSN 2153-6996
Keyword
radio occultation, GPS, marine boundary layer
National Category
Meteorology and Atmospheric Sciences
Identifiers
urn:nbn:se:bth-15745 (URN)10.1109/IGARSS.2017.8127984 (DOI)000426954604121 ()978-1-5090-4951-6 (ISBN)
Conference
2017 IEEE International Geoscience and Remote Sensing Symposium (IGARSS), Fort Worth
Available from: 2018-01-11 Created: 2018-01-11 Last updated: 2018-04-12Bibliographically approved
Vu, V. T., Pettersson, M., Machado, R., Dammert, P. & Hellsten, H. (2017). False Alarm Reduction in Wavelength-Resolution SAR Change Detection Using Adaptive Noise Canceler. IEEE Transactions on Geoscience and Remote Sensing, 55(1), 591-599
Open this publication in new window or tab >>False Alarm Reduction in Wavelength-Resolution SAR Change Detection Using Adaptive Noise Canceler
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2017 (English)In: IEEE Transactions on Geoscience and Remote Sensing, ISSN 0196-2892, E-ISSN 1558-0644, Vol. 55, no 1, p. 591-599Article in journal (Refereed) Published
Abstract [en]

This paper introduces a method to reduce false alarms in wavelength-resolution synthetic aperture radar (SAR) change detection and aims at very high frequency-band systems like the Coherent All Radio Band System (CARABAS). The false alarms are usually caused by the elongated structures, such as power lines and fences, which stand out from the background. The responses of elongated structures are sensitive to flight path. The introduced method aims at minimizing the false alarms caused by the elongated structures and is based on the well-known adaptive processing mechanism, i.e., the so-called adaptive noise canceler (ANC) where a separate reference signal is required. The changes between measurements are considered by the input signal of ANC while the separate reference signal comes from the measurements without change. Hence, the method requires three SAR images associated with three measurements, with no changes between two of them. The reference data for the study are provided by CARABAS. The experimental results indicate that the method can reduce false alarms significantly and provide high probability of detection (≥98%). The experimental results also show that the method still works well even in the case where the flight tracks of the SAR system in the change detection measurements are slightly different.

Keyword
Adaptive signal processing; change detection; statistics; synthetic aperture radar (SAR)
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:bth-13888 (URN)10.1109/TGRS.2016.2611684 (DOI)000391527900046 ()
Available from: 2017-02-21 Created: 2017-02-21 Last updated: 2017-11-29Bibliographically approved
Pettersson, M., Vu, V. T., Gomes, N. R., Dammert, P. & Hellsten, H. (2017). Incoherent detection of man-made objects obscured by foliage in forest area. In: International Geoscience and Remote Sensing Symposium (IGARSS): . Paper presented at 37th Annual IEEE International Geoscience and Remote Sensing Symposium, IGARSS, Fort Worth (pp. 1892-1895). Institute of Electrical and Electronics Engineers Inc.
Open this publication in new window or tab >>Incoherent detection of man-made objects obscured by foliage in forest area
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2017 (English)In: International Geoscience and Remote Sensing Symposium (IGARSS), Institute of Electrical and Electronics Engineers Inc. , 2017, p. 1892-1895Conference paper, Published paper (Refereed)
Abstract [en]

The paper introduces a new likelihood ratio test (LRT) for incoherent detection of man-made objects obscured by foliage in forest area. The test is performed to detect changes between a reference image and a surveillance image. The method is developed for change detection in high resolution Synthetic Aperture Radar (SAR). For simplicity and lack of more appropriate models, the new LRT is still based on simple and efficient models. If there is no man-made object, the statistical model for clutter and noise of two images will be a bivariate Rayleigh distribution. In contrary, a joint distribution of Rayleigh and uniform is used to model for target, clutter, and noise. The proposed LRT is evaluated using radar data acquired by CARABAS in northern Sweden. The probability of detection is up to 96% with much less than one false alarm per square kilometer. © 2017 IEEE.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers Inc., 2017
Series
IEEE International Symposium on Geoscience and Remote Sensing IGARSS, ISSN 2153-6996
Keyword
Change Detection, LRT, Rayleigh, SAR
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:bth-15923 (URN)10.1109/IGARSS.2017.8127347 (DOI)000426954602003 ()2-s2.0-85041836105 (Scopus ID)9781509049516 (ISBN)
Conference
37th Annual IEEE International Geoscience and Remote Sensing Symposium, IGARSS, Fort Worth
Available from: 2018-02-22 Created: 2018-02-22 Last updated: 2018-04-12Bibliographically approved
Vu, V. T., Sjögren, T., Pettersson, M. & Dahl, M. (2017). Measurement of traffic flows with SAR: Field test on the swedish road network. In: International Geoscience and Remote Sensing Symposium (IGARSS): . Paper presented at 37th Annual IEEE International Geoscience and Remote Sensing Symposium, IGARSS,Forth Worth (pp. 3321-3324). Institute of Electrical and Electronics Engineers Inc.
Open this publication in new window or tab >>Measurement of traffic flows with SAR: Field test on the swedish road network
2017 (English)In: International Geoscience and Remote Sensing Symposium (IGARSS), Institute of Electrical and Electronics Engineers Inc. , 2017, p. 3321-3324Conference paper, Published paper (Refereed)
Abstract [en]

This paper reports the measurement campaign Blekingetraffic that was performed by Blekinge Institute of Technology with collaboration with the partners. The measurements are part of a case study to evaluate the feasibility of spaceborne SAR for measuring traffic flow change before and after toll charge introduced in Sweden. The radar measurements were conducted around Pukavik, western of Karlshamn, Sweden in the end of 2015 and in the beginning of 2016. In this paper, the results of one of the controlled measurements performed in the first week of February 2016 is presented. In the ground scene, some trucks tracked with GPS were deployed in European route E22 and local roads. The trucks have either cabinets or food tankers resulting in different radar cross sections. The data acquisition is with TanDEM-X using two satellites giving up to 6 data channels. Since the measurements were performed at 5:00 pm there were unknown traffic i.e. trucks and cars that were not controlled. Therefore, the traffic on the roads was recorded by cameras next to the road and on a drone. The initial analysis of the measured data shows the possibilities to apply available processing techniques such as ground moving target indication and change detection to obtain the knowledge of traffic flow change. © 2017 IEEE.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers Inc., 2017
Series
IEEE International Symposium on Geoscience and Remote Sensing IGARSS, ISSN 000426954603103
Keyword
change detection, SAR, STAP, TanDEM-X, TerraSAR-X, traffic monitoring
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:bth-15924 (URN)10.1109/IGARSS.2017.8127708 (DOI)000426954603103 ()2-s2.0-85041860005 (Scopus ID)9781509049516 (ISBN)
Conference
37th Annual IEEE International Geoscience and Remote Sensing Symposium, IGARSS,Forth Worth
Available from: 2018-02-22 Created: 2018-02-22 Last updated: 2018-04-12Bibliographically approved
Vu, V. T., Pettersson, M. & thomas, S. (2017). Moving Target Focusing in SAR Image with Known Normalized Relative Speed. IEEE Transactions on Aerospace and Electronic Systems, 53(2), 854-861
Open this publication in new window or tab >>Moving Target Focusing in SAR Image with Known Normalized Relative Speed
2017 (English)In: IEEE Transactions on Aerospace and Electronic Systems, ISSN 0018-9251, E-ISSN 1557-9603, Vol. 53, no 2, p. 854-861Article in journal (Refereed) Published
Abstract [en]

This paper presents the moving target focusing method, whichallows focusing moving targets in complex synthetic aperture radar(SAR) images without raw data. The method is developed on the rangemigration algorithm, where focusing moving target is an interpolationstep in the wave domain. The simulated results are provided in thepaper to illustrate the proposed method whereas the experimentalresults show its practicality. The method can be flexibly applied fromsmall area to the whole SAR scene.

Place, publisher, year, edition, pages
IEEE, 2017
Keyword
Engineering, Aerospace; Engineering, Electrical & Electronic; Telecommunications
National Category
Signal Processing
Identifiers
urn:nbn:se:bth-14153 (URN)10.1109/TAES.2017.2665358 (DOI)000400905700026 ()
Available from: 2017-05-08 Created: 2017-05-08 Last updated: 2017-06-13Bibliographically approved
Vu, V. T., Pettersson, M., Gomes, N., Dammert, P. & Hellsten, H. (2017). Wavelength-resolution SAR change detection with constant false alarm rate. In: 2017 IEEE Radar Conference, RadarConf 2017: . Paper presented at 2017 IEEE Radar Conference, RadarConf, Seattle (pp. 1504-1508). Institute of Electrical and Electronics Engineers Inc.
Open this publication in new window or tab >>Wavelength-resolution SAR change detection with constant false alarm rate
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2017 (English)In: 2017 IEEE Radar Conference, RadarConf 2017, Institute of Electrical and Electronics Engineers Inc. , 2017, p. 1504-1508Conference paper, Published paper (Refereed)
Abstract [en]

The paper introduces an incoherent change detection algorithm with constant false alarm rate (CFAR). The algorithm is based on a CFAR detector that preceded with an adaptive noise smoothing filter while the input of the filter is preliminary changes retrieved from a subtraction of surveillance SAR image to reference SAR image. The algorithm is tested with 24 data sets provided by CARABAS. The average probability of detection calculated for 1200 deployed vehicles is up to 96% while the false alarm rate calculated for an area of 288 square kilometers is only 0.15 per square kilometer. In our test, the algorithm did not require a longer processing time than other wavelength-resolution SAR change detection algorithms. Based on these evaluations, the introduced algorithm is seen to be effective. © 2017 IEEE.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers Inc., 2017
Series
IEEE Radar Conference, ISSN 1097-5764
Keyword
Alarm systems, Errors, Radar, Radar imaging, Signal detection, Adaptive noise, Change detection, Change detection algorithms, Constant false alarm rate, False alarm rate, Probability of detection, Processing time, Wavelength resolution, Synthetic aperture radar
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering Signal Processing
Identifiers
urn:nbn:se:bth-15011 (URN)10.1109/RADAR.2017.7944445 (DOI)000405307600286 ()2-s2.0-85021454303 (Scopus ID)9781467388238 (ISBN)
Conference
2017 IEEE Radar Conference, RadarConf, Seattle
Available from: 2017-08-23 Created: 2017-08-23 Last updated: 2017-08-24Bibliographically approved
Javadi, M. S., Dahl, M. & Pettersson, M. (2016). Change detection in aerial images using a Kendall's TAU distance pattern correlation. In: PROCEEDINGS OF THE 2016 6TH EUROPEAN WORKSHOP ON VISUAL INFORMATION PROCESSING (EUVIP): . Paper presented at 2016 6th European Workshop on Visual Information Processing (EUVIP), Marseille. IEEE
Open this publication in new window or tab >>Change detection in aerial images using a Kendall's TAU distance pattern correlation
2016 (English)In: PROCEEDINGS OF THE 2016 6TH EUROPEAN WORKSHOP ON VISUAL INFORMATION PROCESSING (EUVIP), IEEE, 2016Conference paper, Published paper (Refereed)
Abstract [en]

Change detection in aerial images is the core of many remote sensing applications to analyze the dynamics of a wide area on the ground. In this paper, a remote sensing method is proposed based on viewpoint transformation and a modified Kendall rank correlation measure to detect changes in oblique aerial images. First, the different viewpoints of the aerial images are compromised and then, a local pattern descriptor based on Kendall rank correlation coefficient is introduced. A new distance measure referred to as Kendall's Tau-d (Tau distance) coefficient is presented to determine the changed regions. The developed system is applied on oblique aerial images with very low aspect angles that obtained using an unmanned aerial vehicle in two different days with drastic change in illumination and weather conditions. The experimental results indicate the robustness of the proposed method to variant illumination, shadows and multiple viewpoints for change detection in aerial images.

Place, publisher, year, edition, pages
IEEE, 2016
Keyword
Aerial images, change detection, Kendall rank correlation, optical remote sensing
National Category
Signal Processing
Identifiers
urn:nbn:se:bth-13878 (URN)10.1109/EUVIP.2016.7764604 (DOI)000391630800023 ()978-1-5090-2781-1 (ISBN)
Conference
2016 6th European Workshop on Visual Information Processing (EUVIP), Marseille
Available from: 2017-02-03 Created: 2017-02-03 Last updated: 2017-02-21Bibliographically approved
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Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-6643-312x

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