Evenemanget pågår:
2012-12-21

PhD: Synthetic Aperture Radar signal and image ...

PhD: Synthetic Aperture Radar signal and image processing for moving target indication and side lobe supression

Doktorand Thomas Sjögren försvarar sin doktorsavhandling i ämnet Tillämpad Signalbehandling den 21 december.

Tid: 21 december 2012 kl. 10:15
Plats:
Sal G340, BTH, Campus Gräsvik, Karlskrona

Avhandlingens titel: Synthetic Aperture Radar signal and image processing for moving target indication and side lobe supression

Forskarutbildningsämne: Tillämpad Sigbalbehandling

Huvudhandledare och examinator: Professor Mats Pettersson, BTH

Opponent: Dr Ishuwa Sikaneta, Defence Research & Development, Canada


Betygsnämnd:

  • Professor Pierfrancesco Lombardo, University Rome, Italy
  • Docent Thomas Rylander, Chalmers Tekniska Högskola, Göteborg
  • Dr Patrik Dammert, Saab EDS, Göteborg


Betygsnämndssuppleant:
Professor Claes Hedberg, BTH

Anmälan om deltagande görs till administration BTH-ING senast den 10 december.

Länk till uppsatsen


Abstract

The thesis summarizes a selection of my research within Synthetic Aperture Radar (SAR). Mainly the research is aimed at applying and developing signal processing methods to single channel and multi channel SAR for wideband systems. SAR systems can generate images looking very similar to optical pictures, i.e. photos, and sometimes with much finer resolution compared to optical systems orbiting Earth. SAR has also for instance been used to obtain fine resolution images of the moon, Venus and the satellites of Saturn. It has for instance also been used to detect changes fine ice sheets and deforestation. In this thesis, SAR systems capable of very high resolution imaging are considered, and data from such systems, namely the VHF system CARABAS-II and the UHF system LORA, is used. Two of the topics in this thesis are related to detection and parameter estimation of moving targets in SAR, the first one using CARABAS-II data and the second with LORA data. On the CARABASII data, a speed estimation and refocusing method is introduced and applied to single channel CARABAS-II data. The results show good estimation accuracy as well as good ability to focus the target and suppress forest clutter by applying the refocusing algorithm. The results on LORA data are very good especially with regard to forest clutter suppression. The ability to detect and focus images of ships allow for surveillance of coastal areas and help in rescue of ships lost at sea. Detection and location of cars and trucks allow for trac monitoring to obtain statistics of how many cars travel the roads and their speed. Two further topics present important aspects for SAR processing. One paper presents windowing of UWB SAR images. A strong object such as a power line in a SAR image cause ringing on both sides of the power line. This ringing can cause a small house to be covered by these so called side lobes.
Applying a window can make these side lobes in the image much suppressed, however if windowing too much, the power line will smear over the image, covering the small house. The last topic in the thesis concern with theoretical limits for measurement accuracy of parameters for a moving object in a SAR image. These parameters are position, velocity, radar cross section and phase. The theoretical expressions are veri ed using simulations for a single channel
system for estimation accuracy of target speed and relative speed.

Arrangör, person/sektion/organisatör:
Sektionen för ingenjörsvetenskap

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