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88 results on '"Vu, Viet T."'

51. Derivation of Bistatic SAR Resolution Equations Based on Backprojection.

Author

Vu, Viet T. and Pettersson, Mats I.

Abstract

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. [ABSTRACT FROM PUBLISHER]

Published
2018
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52. SAR image statistics and adaptive signal processing for change detection

Author

Vu, Viet T., Machado, Renato, Pettersson, Mats I., Dammert, Patrik, Hellsten, Hans, Vu, Viet T., Machado, Renato, Pettersson, Mats I., Dammert, Patrik, and Hellsten, Hans

Abstract

The paper presents investigations on SAR image statistics and adaptive signal processing for change detection. The investigations show that the amplitude distributions of SAR images with possibly detected changes, that is retrieved with a linear subtraction operator, can approximately be represented by the probability density function of the Gaussian or normal distribution. This allows emerging the idea to use the available adaptive signal processing techniques for change detection. The experiments indicate the promising change detection results obtained with an adaptive line enhancer, one of the adaptive signal processing technique. The experiments are conducted on the data collected by CARABAS, a UWB low frequency SAR system.

Published
2015
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53. Performance of Moving Target Parameter Estimation Using SAR

Author

Pettersson, Mats, Sjögren, Thomas K., Vu, Viet T., Pettersson, Mats, Sjögren, Thomas K., and Vu, Viet T.

Abstract

Synthetic aperture radar (SAR) gives not only the opportunity to image targets with high resolution but also to measure their position and velocity. Without acceleration (constant speed), the position and velocity both in range and azimuth can be estimated using a multichannel SAR system. This paper introduces a method to find the lower bound on variance of estimate of position and velocity for targets. The method is based on the assumptions needed for the Cramer-Rao lower bound (CRLB). The method works for both narrowband (NB) and ultrawideband (UWB) SAR systems. For demonstration, a monostatic single-channel UWB SAR system operating at low frequency is used. Thus, only lower bounds for estimate variance of azimuth, range, and relative speed are derived.

Published
2015
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82. Forest clutter suppression for moving target detection in UHF dual channel SAR.

Author

Sjogren, Thomas K., Vu, Viet T., Pettersson, Mats I., Murdin, Daniel, Gustavsson, Anders, Ulander, Lars M.H., and Wang, Feng

Abstract

In this paper one way to combine UHF Synthetic Aperture Radar (SAR) processing with MIMO radar is shown. The SAR processing is conducted in the time domain using a fast back projection algorithm (FBP). Each channel is SAR processed separately until a middle stage. Some results have been obtained using 2-channel data from the LORA system. The experimental results show that it is possible to estimate target speed parameters as well as it is possible to suppress forest clutter significantly in the SAR images. For the specific dataset used, the SAR data collection time is 4.6s and the target is a truck with a corner reflector mounted on the back. The results show a good ability to suppress the forest clutter while not suppressing the target signal. Also, in order to obtain the correct target speed components in azimuth and range for focusing, the target dynamic parameters in target focusing and in the steering vector were regulated. [ABSTRACT FROM PUBLISHER]

Published
2013

83. An experimental ground-based SAR system for studying SAR fundamentals.

Author

Vu, Viet T., Nehru, Dheeraj N., Pettersson, Mats I., and Sjogren, Thomas K.

Abstract

The paper introduces a simple experimental ground-based SAR (GB-SAR) system for studying SAR fundamentals. The SAR system is developed on a vector network analyzer (VNA), for example Agilent E5071C, with some useful built-in functions such as transform and gating. The procedure of acquiring the data by using the SAR system is presented in details. The acquired empirical data is also used to reconstruct the illuminated scene. The possibilities to use the SAR system to support SAR research topics are also discussed in this paper. [ABSTRACT FROM PUBLISHER]

Published
2013

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