MIMO RADAR chap 2.pptx

7/28/2019 MIMO RADAR chap 2.pptx

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MIMO RADAR:

CONCEPTS,PERFORMANCE ENHANCEMENTS,

AND

APPLICATIONS

By-Saurabh Shukla

M.Tech (CE)ICE2012005


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CONTENTS

Introduction

Notations

MIMO Radar Virtual Aperture

MIMO Radar in Clutter Free Environment

Optimality of Radar for Detection

MIMO Radar with moving targets in Clutter : GMTIRadars 2


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1. INTRODUCTION

1.1-A SHORT HISTORYOF RADAR-

By 1904, Christian Hulsmeyer had developed and

patented a spark-gap transmitterreceiver system for

naval navigation.

In 1935, Sir Robert Watson-Watt demonstrated and

patented a working radar system. This system had all

the essential characteristics of a useful radar.

Synthetic aperture radar (SAR) became an active

area of research during the end of 1950.

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In the 1960s, the development of phased-array

antennas became an important area of research,

allowing radars to quickly change search direction.

During the 1970s, digital signal processing became

viable, and was applied to radar processing,

enabling adaptive array processing and the modernradar system.

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1.2-DEFINITION AND CHARACTERISTICS OF

MIMO RADAR

The notion of MIMO radar is simply that there aremultiple radiating and receiving sites.

Fig 1- Basic MIMO radar.

The location of the m-th transmitter is given by xm,and the location of the n-th receiver is given by yn.

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The collected information is then processedtogether.

RIAS & SIAR radar are the early example of MIMORadars.

By the most general definition, many traditional

systems can be considered as special cases ofMIMO radars.

As an example, SAR can be considered as a form

of MIMO radar.

Although SAR traditionally employs a singletransmit antenna and a single receive antenna

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The positions of these two antennas are translated and

images are formed by processing all the information jointly.

SAR radar does not have access to channel

measurements for all transmitreceive position pairs.

This is the significant difference between the SAR radar

and a typical MIMO radar, which takes full advantage ofthe degrees of freedom.

Various possible signaling techniques are used for MIMO

radar. The transmit antennas radiate signals, which may ormay not be correlated, and the receive antennas attempt

to disentangle these signals.

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It is assumed that the waveforms coming from eachtransmit antenna are orthogonal.

There is a continuum of MIMO radar systems concepts;however, there are two basic regimes of operation.

In the first regime, the transmit array elements (andreceive array elements) are broadly spaced, providing

independent scattering responses for each antennapairing, sometimes referred to as statistical MIMO radar.

In the second regime, the transmit array elements (andreceive array elements) are closely spaced so that thetarget is in the far field of the transmitreceive array,sometimes referred to as coherent MIMO radar.

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Answer to the question How large must the angular separation be toget independent scattering responses? is dependent on the details ofthe target.

As shown in Fig. 2, if an array of appropriately phased scatterers ofthe physical size of the target can resolve individual locations of theantennas, then independent scattering responses would theoretically

be possible.

Fig 2-Coherent versus incoherent scattering response.

Conversely, if the overall angular antenna separation were smallcompared to the beamwidth of the scatterer array, then coherentprocessing would be viable.

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1.3-USESOF MIMO RADAR

Improved target detection performance

Improved angle estimation accuracy

Decreased minimum detectible velocity

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2. NOTATION

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