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MUFFAKHAMJAH COLLEGE OF ENGGINEERING AND TECHNOLOGY

DEPARTMENT OF ELECTRONICS AND COMMUNICATION.

A TECHNICAL PRESENTATIONON

DETECTION AND ESTIMATION OF COHERRENT SIGNALS

BY PROJECT GUIDE

SHAIK MOHAMMED NAWAZ(04084023) AYEESHA NAAZSHAIK ASWATH HUSSAIN(04084142L) ASSOCIATE .PROFMOHAMMMED KHADEER(04084046). MJCET.HYDERABAD.

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OUTLINE:

1. Back ground

2. What is Array Signal Processing???

3. Direction of arriaval (DOA)estimation.4. ESPRIT

5. Applications of DOA

6. References.

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OBJECTIVE.

Discuss sensor Arrays signal processing and similarities

to antenna arrays processing.

Investigate various direction of arrival(DOA) techniques.

Applications of DOAs

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ARRAY SIGNAL PROCESSING.

An array of sensors, distributed over a

horizontal plane surface, is used to receive a

propagating wave field with the following

objectives:

To localize a source. To receive a message from a distant

source.(DOA)

To image a medium through which the wave

field is propagating

Detect number of signals

U

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BASIC ARRAY CONFIGURATIONS

Uniform linear array

Uniform planar array

Uniform circular array

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DIRECTIONOF ARRIVAL

ESTIMATION(DOA)

DOA involves computing the spatialspectrum and determining the maximas.

Maximas correspond to DOAs

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DIRECTION OF ARRIVAL ESTIMATION

ALGORITHMS

The DOA algorithm must satisfy the following conditions :

Low computational intensity (MIPS/MFLOPS)

High accuracy (RMSE)

High speed

Easy implementation

Good performance at low SNRs

Works on a 2 microphone array system with 4cm

separation between them.

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DIRECTIONOF ARIVAL(DOA)

METHODS.

DOA

CLASSICAL

Delay and sum method

Minimum variance distortion lessresponse(MVDR) method

Subspacemethods

Estimation of signal parameters viarotational invarience technique(ESPRIT)

Multiple signal classification (algorithm)

Maximumlikelihood(ML)

techniques

Alternating projection algorithm(APA)

ESPRIT is explored in this presentation

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ESTIMATION OF SIGNAL PARAMETERS VIA ROTATIONAL

INVARIANCE TECHNIQUE(ESPRIT)

Basic assumption in ESPRIT is that a group of sensors can be

divided in two sub arrays so that sub arrays are geometric copies

of each other.

Calibration is not needed between sub arrays Assumes number of sources < Number of antenna elements.

else signals may be poorly resolved

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MATHEMATICALMODEL OFESPRIT

Xn=ASn+Vn(x)

Yn=Asn+Vn(x)

is a digonal matrix rxr Zn= | Xn | = AbSn+Vn

| Yn |

R is the covarience matrix of z.

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PETTERNFORMINGNETWORK.

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ESPRITALGORITM

Calculate Rzz from observationsof z

Estimate the number of sources:d

Pick the eigenvectors corresponding to the d largest eigenvalues of Rzz to contruct Es

Partition Es into dxd submatrices

Es= e11 e12

e21 e22

Compute the DOAs k= arcsin(arg( k)/2 )

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QR ESPRITALGORITHM.

Compute the signalsubspace:

E=|Ex^r Ey^r| r

QR decomposition ofE E=QR

Let R=Q^hER^-1

Eigenalues of Rgive the DOAs

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DOA Method Equation for Implementation

Delay and Sum

Minimum Variance

MUSIC

Coherent MUSIC

Root MUSIC

ESPRIT

*( ) ( ) ( ) P a SaU U U!

*

1( )

( ) ( ) ( )P

a inv s aU

U U!

*

* *

( ) ( )( )

( ) ( )N N

a aP

a E E a

U UU

U U

!

'( )

' 'N N

a aP

a E E aU !

_ a1 0sin . ( ) /( )K c angle z d U [

!

_ a10

sin arg( ) /( )K K

c dU J [

!


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APPLICATIONS OFDOA

DOA estimation is a very important technique both in wireless

telecommunication system and audio/speech processing system

The estimated DOAs of incoming signals can be used to suppress

the interference and enhance the desired signal in an adaptivearray sensor system

Another applicable field of DOA estimation is robotics

It can deal with signals up to the number of sensors, and because

its unnecessary to search nulls of directivity patterns, the

calculation cost is reduced.

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CONCLUSION. The conclusions based on the results of this simulation study are summarized as follows:

1. The ESPRIT method estimates signal DOA by finding the roots of two independent

equations closest to the unit circle. This method does not require using a scan vector to

scan over all possible directions like the MUSIC (Multiple Signal Classification)

algorithm.

2. Estimation error is relatively independent of signal azimuth angle if the signal

impinging the array from low elevation angle.

3. When the signal impinging the array from high elevation angle, there are some critical

azimuths angles that yield a very large estimation error. This is due to the fact that at

those critical azimuth angles, the received data vectors are very close. Thus there is not

sufficient information to process the received data. To avoid large estimation error, we

suggest to alternatively choosing a different subset and shifting the subset in different

directions.

4. Estimation error can be reduced by (a) using an array containing a large number of

elements, (b) increasing the number of temporal averaging in matrix element estimation.

5. Array element position may deviate from the ideal position. Position deviation will

degrade DOA performance. Sensitivity analysis due to imprecise element position will

be carried out in future study.

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REFERENCES.

Direction finding for wideband signals using an intrerpolatedarray, IEEE trans. Siganl proc,vol.41,n0.4,pp.1618-1634

Monthippa uthansakul and marek e bialkowski, an arrayantenna with wideband beam steering capability employing

spatial signal processing, IEEE transaction ,2010

Books:

1. Sensor array signal processing by prabhakar s naidu.

2. Narrowband direction of arrival estimation for antennaarrays. By jeffery foutz

3. Classical and modern direction of arrival estimation bybenjimen

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Queries?????

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Wewouldliketo thank

Ayesha naaz madam andrangaiahsir forguidingus

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