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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Simulation-based Comparison Of Some Gmti Techniques

Baktir, Can 01 March 2009 (has links) (PDF)
With the developing radar technology, radars have been started to be used in the airborne platforms due to the need of fast, accurate and reliable information about the enemies. The most important and tactically needed information is the movements in an observation area. The detection of a ground moving target buried in a dense clutter environment from a moving air platform is a very challenging problem even today. The geometry of the operation, the course of the flight and structure of the clutter are the most effective parameters of this problem. There are some &ldquo / Ground Moving Target Indication&rdquo / (GMTI) techniques that have been studied for the last twenty years to overcome this problem. In this thesis, the simulation of some of these techniques in a realistic environment and the comparison of their performances are discussed. In this work, a GMTI simulator is developed to generate the environment containing the clutter and the noise signals, to locate and simulate the targets in this environment and to apply the GMTI techniques on the raw data generated by the simulator. The generation of the clutter signals including the internal clutter motion (ICM) for different types of clutter distributions is one of the most important parts of this thesis. The GMTI techniques being investigated throughout this thesis are &ldquo / Displaced Phase Center Antenna&rdquo / (DPCA), &ldquo / Along-Track Interferometry&rdquo / (ATI), &ldquo / Adaptive DPCA&rdquo / , &ldquo / Pre-Doppler Sigma-Delta STAP&rdquo / and &ldquo / Post-Doppler Sigma-Delta STAP&rdquo / techniques. These techniques are compared according to their clutter suppression and target detection performances under different environmental conditions.
12

Antenna Patterns For Detecting Slowly Moving Targets In Two Channel Gmti Processing

Yildirim, Gokhan 01 June 2010 (has links) (PDF)
Ground Moving Target Indicator (GMTI) is a well-known and widely used signal processing method in airborne and spaceborne radars. In airborne radar and GMTI literature, many radar designs and signal processing techniques have been developed to increase the detection and estimation performance under heavy interference conditions. The motion of the aircraft on which the radar is mounted, high altitudes and ranges, targets with low radar cross sections and slowly moving targets complicates the problem of localization and observation of moving targets on a huge area of interest. In order to overcome these problems, engineers developed more complex radar hardwares with many receiver channels and signal processing algorithms. Multi-channel receivers provide adaptive digital beam-forming and adaptive Doppler processing capabilities. However, designing a cost efficient and light multi-channel receiver and a signal processing unit, which can handle a huge amount of received data from multi channels, is a difficult task to accomplish. Therefore, this thesis aims to propose non-adaptive antenna beams to reduce the number of channels to two in GMTI processing. This reduction yields a simplification both in receiver structure and signal processing unit. The measure of excellence of these propositions will be the ability to detect slowly moving targets with nearly optimum performance.

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