Faz-MIMO radar
Faz-MIMO radar
Yazar: ÇAĞATAY GÜRBÜZ
Danışman: DOÇ. DR. ENDER METE EKŞİOĞLU
İstanbul Teknik Üniversitesi / Bilişim Enstitüsü / İletişim Sistemleri Ana Bilim Dalı / Uydu Haberleşmesi ve Uzaktan Algılama Bilim Dalı
Derece: Yüksek Lisans, 2014
Konu: Mühendislik Bilimleri = Engineering Sciences

Özet:
Tezin, altı ana başlık altında toplandığı görülmektedir. Birinci kısım, tezin üzerine yoğunlaştığı konsept faz-MIMO radar tekniğinin kavranmasının kolaylaştırılması için altyapı oluşturacak biçimde sırasıyla radar sistemleri, MIMO radar sistemleri, faz-dizi radar sistemleri, faz-MIMO radar tekniği, benzetim sonuçları hakkında çok kısa bilgi veren ve buna bağlı olarak tezin genelini kapsayacak ve yapılan çalışmaya açıklama teşkil edecek nitelikte bir giriş kısmıdır.
İkinci kısımdan itibaren genel giriş tanımından uzaklaşılarak, daha spesifik nitelikte teknik bilgi verilmeye başlanmıştır. Bu kısımda radar sistemleri üzerinde durulmuş, radar sistemleri, uygulama alanları ve temel fonksiyonları başlıkları altında tespit ve mesafeleme, hız kestirimi ve huzme şekillendirmeden bahsedilerek esas hatları ile ifade edilmeye çalışılmıştır. İlerleyen bölümlerde anlatılacak olan MIMO radar, faz-dizi radar ve bunların kısmen harmanlandığı bir teknik olan faz-MIMO radar teknikleri için ortak bir zemin olarak radar sistemleri sunulmuştur.
MIMO radar ve faz-dizi radar sistemlerinden bahsettiğimiz üçüncü kısımda, tezin üzerine bina edildiği konsept olan faz-MIMO radar sistemi için altyapı teşkil eden bu iki sistem, detaylı bir biçimde sunulmuştur. Multistatik radar sistemleri başlığını takiben, faz-dizi radar başlığı altında, faz-dizi radar konseptine ışık tutulmaya çalışılmıştır. Bunu takip eden bölümde MIMO radar konseptine giriş yapılmış, yapışık (coherent) MIMO radar, istatistiksel MIMO radar başlıkları altında MIMO radar tekniği sunulmuş, sonraki başlıkta ise bu tekniğin sunduğu yenilikler belirtilmiştir. 
Dördüncü kısım, tezin başlığı faz-MIMO radar tekniğine genel bir giriş yapılmıştır. Genel konseptin açıklanmasını takiben, önerilen faz-MIMO radar formülasyonları belirtilmiş, dikkate alınması gereken pratik hususlar üzerinde durulmuş, faz-MIMO radarlarda iletim/alım huzme şekillendirme, adaptif olmayan iletim/alım huzme şekillendirme, baskın gürültü gücü, baskın girişim, sağlam/adaptif huzme şekillendirme konseptleri ifade edilerek faz-MIMO radarın diğer iki radar türü olan faz-dizi ve MIMO radar ile performans karşılaştırmasının yapılacağı benzetim ortamı hakkında gerekli bilgi verilmeye çalışılmıştır. 
Beşinci kısımda, faz-dizi radar ve MIMO radar konseptlerini harmanlayan faz-MIMO radar sisteminin performans nitelikleri benzetim yoluyla yine bu sistemlerle kıyaslanmış, karşılaştırmalı sonuçlar gerekli görsellerle desteklenerek ifade edilmeye çalışılmıştır.
Sonuç başlığı altında sunulan son kısımda sunulan bu yeni teknik genel hatlarıyla yorumlanmış, geçmiş anlatımlar ve benzetim sonuçlarının da eldesiyle konsepte ve çalışmaya genel bir yorum getirilmek amaçlanmıştır.

Abstract:
This thesis consists of six main titles. The aim of the first section, is to make easier to understand about the phased-MIMO radar technique which is the main concept of the thesis. Radar systems, MIMO radar systems, phased-array radar systems, phased-MIMO technique, simulation concept, simulation results were mentioned briefly and related to all them, in first section an introduction is available. 
The second section moving from the general concept definition to more specifical technical information has been given. Radar is an object-detection system that uses radio waves to determine the range, altitude, direction, or speed of objects. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, weather formations and terrain. The radar dish or antenna transmits pulses of radio waves or microwaves that bounce off any object in their path. The object returns a tiny part of the wave's energy to a dish or antenna that is usually located at the same site as the transmitter. In this section radar systems have been studied radar systems in areas of usage to detecting and ranging, velocity estimation and beamforming under the heading mainly line with expression were examined. MIMO radar, phase-array radar and their partially blended technique phase-MIMO radar have been presented on a common ground which named radar systems.
MIMO radar and phased-array radar systems were mentioned in this third section, which is the main subject of the thesis phased-MIMO radar system infrastructure that constitute the two systems are presented in detail. In radio, multiple-input and multiple-output, or MIMO (pronounced my-moh by some and me-moh by others), is the use of multiple antennas at both the transmitter and receiver to improve communication performance. It is one of several forms of smart antenna technology.
MIMO technology has attracted attention in wireless communications, because it offers significant increases in data throughput and link range without additional bandwidth or increased transmit power. It achieves this goal by spreading the same total transmit power over the antennas to achieve an array gain that improves the spectral efficiency (more bits per second per hertz of bandwidth) and/or to achieve a diversity gain that improves the link reliability (reduced fading). Because of these properties, MIMO is an important part of modern wireless communication standards such as IEEE 802.11n (Wi-Fi), 4G, 3GPP Long Term Evolution, WiMAX and HSPA+. More recently MIMO signal processing has also found its way into power line communications (PLC) as part of standard ITU G.hn and specification HomePlug AV2.
A multistatic radar system contains multiple spatially diverse monostatic radar or bistatic radar components with a shared area of coverage. An important distinction systems based on these individual radar geometries is the added requirement for some level of data fusion to take place between component parts. The spatial diversity afforded by multistatic systems allows for different aspects of a target to be viewed simultaneously. The potential for information gain can give rise to a number of advantages over conventional systems.
Multistatic radar is often referred to as 'multisite' or 'netted' radar, and is comparable with the idea of macrodiversity in communications. A further subset of multistatic radar with roots in communications is that of MIMO radar.
In antenna theory, a phased array is an array of antennas in which the relative phases of the respective signals feeding the antennas are varied in such a way that the effective radiation pattern of the array is reinforced in a desired direction and suppressed in undesired directions. 
An antenna array is a group of multiple active antennas coupled to a common source or load to produce a directive radiation pattern. Usually, the spatial relationship of the individual antennas also contributes to the directivity of the antenna array. Use of the term "active antennas" is intended to describe elements whose energy output is modified due to the presence of a source of energy in the element (other than the mere signal energy which passes through the circuit) or an element in which the energy output from a source of energy is controlled by the signal input. One common application of this is with a standard multiband television antenna, which has multiple elements coupled together.
Multistatic radar systems, phase-array radar signal model, phase-array radar under the headings identified, phased-array radars have been explained. The subsequent section MIMO concept is introduced and coherent MIMO, statistical MIMO radar, MIMO radar concept offers innovations are expressed. 
Fourth section of the thesis focused on phased-MIMO radar concept. One of new techniques in recent years for multiple-input multiple-output (MIMO) radar with colocated antennas which is called phased-MIMO radar has been examined. 
This technique enjoys the advantages of the MIMO radar without sacrificing the main advantage of the phased-array radar which is the coherent processing gain at the transmitting side. The essence of the proposed technique is to partition the transmit array into a number of subarrays that are allowed to overlap. Then, each subarray is used to coherently transmit a waveform which is orthogonal to the waveforms transmitted by other subarrays. Coherent processing gain can be achieved by designing a weight vector for each subarray to form a beam towards a certain direction in space. 
Moreover, the subarrays are combined jointly to form a MIMO radar resulting in higher angular resolution capabilities. Substantial improvements offered by the phased-MIMO radar technique as compared to the phased-array and MIMO radar techniques are demonstrated analytically and by simulations through analyzing the corresponding beampatterns and the achievable output signal-to-noise-plus-interference ratios. Both analytical and simulation results validate the effectiveness of the phased-MIMO radar. An introduction to the concept of the phased-MIMO radar is made then following the announcement of general concept, the proposed phased-MIMO radar formulations have been stated to be reckoned with practical elements specified phased-MIMO radar in the transmit / receive beamforming, non-adaptive transmitter / receiver beamforming, the dominant noise power, the dominant interference, robust / adaptive beamforming concepts by expressing the phased-MIMO radar are intended to bring clarity to the subject.
In the fifth section, phased-MIMO radar which is the partial blending of phased-array radar and MIMO radar are compared to them again in simulations, supported by the required visual comperative results have been trying to express.
The results presented in the last section have collected under this new technique broadly interpreted, history, narrative and the concept of simulation results obtained and the work was intended to be a general comment.