Target identification using ISAR imaging techniques

Atılgan, Erdinç Levent
A proper time-frequency transform technique suppresses the blurring and smearing effect of the time-varying Doppler shift on the target image. The conventional target imaging method uses the Fourier transform for extracting the Doppler shift from the received radar pulse. Since the Doppler shift is timevarying for rotating targets, the constructed images will be degraded. In this thesis, the Doppler shift information required for the Range-Doppler image of the target is extracted by using high resolution time-frequency transform techniques. The Wigner-Ville Distribution and the Adaptive Gabor Representation with the Coarse-to-Fine and the Matching Pursuit Search Algorithms are examined techniques for the target imaging system. The modified Matching Pursuit Algorithm, the Matching Pursuit with Reduced Dictionary is proposed which decreases the signal processing time required by the Adaptive Gabor Representation. The Hybrid Matching Pursuit Search Algorithm is also introduced in this thesis work and the Coarse-to-Fine Algorithm and the Matching Pursuit Algorithm are combined for obtaining better representation quality of a signal in the time-frequency domain. The stated techniques are applied on to the sample signals and compared with each other. The application of these techniques in the target imaging system is also performed for the simulated aircrafts.


Nonuform pulse repetition interval optimization for pulse doppler radars
Mercan, Hasan; Tanık, Yalçın; Department of Electrical and Electronics Engineering (2004)
In this thesis, a method of optimization of nonuniform pulse repetition interval for pulse Doppler radars is investigated. PRI jittering technique is used for the selection of inter-pulse intervals. An environment with white Gaussian noise and clutter interference is defined and applying generalized likelihood ratio test, a sufficient statistic function for the detection of the target is derived. The effect of jitter set selection on range and Doppler ambiguity resolution and clutter rejection is investigat...
Nonlinear image restoration
Ungan, Cahit Uğur; Demirbaş, Kerim; Department of Electrical and Electronics Engineering (2005)
This thesis analyzes the process of deblurring of degraded images generated by space-variant nonlinear image systems with Gaussian observation noise. The restoration of blurred images is performed by using two methods; a modified version of the Optimum Decoding Based Smoothing Algorithm and the Bootstrap Filter Algorithm which is a version of Particle Filtering methods. A computer software called MATLAB is used for performing the simulations of image estimation. The results of some simulations for various o...
Use of the ambiguity function technique for target detection in phase coded continuous wave radars
Çankaya, Erkan; Sayan, Gönül; Department of Electrical and Electronics Engineering (2005)
The goal of this thesis study is to investigate the Ambiguity Function Technique for target detection in phase-coded continuous wave radar. Also, phase shift keying techniques are examined in detail. Continuous Wave (CW) Radars, which are also known as Low Probability of Intercept (LPI) radars, emit continuous signals in time which are modulated by either frequency modulation or phase modulation techniques. Modulation of the transmitted radar signal is needed to estimate both the range and the radial veloci...
Target tracking with input estimation
Gazioğlu, Ersen; Demirbaş, Kerim; Department of Electrical and Electronics Engineering (2005)
In this thesis, the target tracking problem with input estimation is investigated. The estimation performance of the optimum decoding based smoothing algorithm and a target tracking scheme based on the Kalman filter is compared by performing simulations. The advantages and the disadvantages of these algorithms are presented.
Noncoherent differential demodulation of CPM signals with joint frequency offset and symbol timing estimation
Çulha, Onur; Tanık, Yalçın; Department of Electrical and Electronics Engineering (2011)
In this thesis, noncoherent differential demodulation of CPM signals with joint carrier frequency offset and symbol timing estimation is investigated. CPM is very attractive for wireless communications owing to major properties: good spectral efficiency and a constant envelope property. In order to demodulate the received CPM signal differentially, the symbol timing and the carrier frequency offset have to be estimated accurately. There are numerous methods developed for the purpose. However, we have not en...
Citation Formats
E. L. Atılgan, “Target identification using ISAR imaging techniques,” M.S. - Master of Science, Middle East Technical University, 2005.