POWER AND COMMUNICATIONS FOR EFFECTING DESIRED 12 ICEPT...

POWER AND COMMUNICATIONS FOR EFFECTING DESIRED

DEVELOPMENTAL CHANGES 12th ICEPT

(2016)

Presenter

U. I. Bature (ATBU Bauchi) 1

CONTENTS

INTRODUCTION 1

MOTIVATION FOR RESEARCH 2

SIMULATION RESULTS AND DISCUSSIONS 4

EMITTER LOCATION ESTIMATION 3

ERRORS IN THE ESTIMATION 5

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CONCLUSION 6

INTRODUCTIONINTRODUCTIONINTRODUCTIONINTRODUCTION

� Radio Direction Finding (RDF) refers to the measurement of the

direction of the transmitted signal. Emitter location has been estimated

based on these measured parameters, namely; the Angle of Arrival

(AOA), Time of Arrival (TOA) or Time Difference of Arrival (TDOA).

� Numerous techniques of RDF have been in use over time to determine

the AOAs, such techniques like the pseudo-Doppler DF techniques,

Watson-Watt/Adcock antenna array and correlative interferometer.

However, correlative interferometer has been the highest tendency of

accurate estimation in AOA.

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INTRODUCTION (INTRODUCTION (INTRODUCTION (INTRODUCTION (ctn…)

� Estimation of emitter location has been applied in various areas like

military intelligence systems, geographical location, navigation of

ships and aircraft.

� Difficulties in emitter location attracts great interest in the signal

processing, underwater acoustics literature and vehicular technology,

this has been witnessed since World War I.

� This paper presents analysis on factors affecting the accuracy of

emitter locating via the derivation of range equations. It was also

discovered that intersection region can be realized using two

baselines, and can also be employed using more baselines for more

accurate evaluation.

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INTRODUCTION (INTRODUCTION (INTRODUCTION (INTRODUCTION (ctn…)

Correlative Interferometer ProcessCorrelative Interferometer ProcessCorrelative Interferometer ProcessCorrelative Interferometer Process

� Correlative Interferometer RDF system is used to determine the angle of

incidence of a received signal by measuring the phase difference between

the signals realized at various points on the received antenna array

elements.

� Correlative interferometer is a process that uses phase differences to

estimate the direction of the incoming signal.

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Correlative Interferometer showing two sensors and Look-up table 5

MOTIVATION FOR RESEARCHMOTIVATION FOR RESEARCHMOTIVATION FOR RESEARCHMOTIVATION FOR RESEARCH

� High need of processing ensue from the execution of

enormous data base of all possible directions (look-up table)

� Existing Direction Finding/Radio Direction Finding systems

have an increased directional error due to weak signal and

multipath.

� High demands in flexibility and accuracy in finding the exact

location of the signal source (emitters) in space .

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EMITTER LOCATION ESTIMATIONEMITTER LOCATION ESTIMATIONEMITTER LOCATION ESTIMATIONEMITTER LOCATION ESTIMATION

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� Baseline Design

� Range Equations

� Process of Triangulation

� Single Baseline

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� Least Squares Approximation

EMITTER LOCATION ESTIMATIONEMITTER LOCATION ESTIMATIONEMITTER LOCATION ESTIMATIONEMITTER LOCATION ESTIMATION 12th ICEPT

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Baseline is a line joining any couple of receiving units, receivers are also termed as sensors that are located on the ground level properly spaced by a distance of from one another.

� Baseline Design

Four Sensor Configuration

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Correlative interferometer compares phase differences for the unknown AOA with the computed and saved data (value) in a table where the maximum correlation resembles the estimated angles. AOA at each receiver will be estimated using this method and further used for locating the emitter position. Therefore, the hypothetical range equations of four receivers were considered as shown below:

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� Range Equations


Triangulation is the process of point estimation, where this point is fixed as the third point of a triangle and also in geometry of a planar object is defined as the subdivision into triangles, triangulation is the process of determining the location of a point by forming triangles to it from known points. Every sensor produces a set of points called hyperbola where the emitter was statistically present. Hyperbola is a set of points in which the difference in distance is always constant. Hyperbola is a set of points at a constant range-difference from two foci, where intersections estimate the actual location of hyperbolas.

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� Process of Triangulation

EMITTER LOCATION ESTIMATIONEMITTER LOCATION ESTIMATIONEMITTER LOCATION ESTIMATIONEMITTER LOCATION ESTIMATION 12th ICEPT

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The equation of the hyperbola was estimated by applying the coordinates of the emitter x, y and the parameters of the receiver to equation of a straight line.

� Single Baseline


Least squares (LS) approximation is a method of approximating a solution of over determined system. The least squares method computes the overall solution and reduces the sum of the squares of the errors made in results of any of the equations. Over determined system have more equations than unknowns. Therefore, this kind of system can have either one solution or no any solution at all.

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� Least Squares Approximation

Fitting a set of points using least-squares approximation

SIMULATION RESULTS AND DISCUSSIONSSIMULATION RESULTS AND DISCUSSIONSSIMULATION RESULTS AND DISCUSSIONSSIMULATION RESULTS AND DISCUSSIONS 12th ICEPT

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Emitter seen at 30degrees and 80km range

� Manipulation of coordinates of these pair of sensors and various angle of arrival projected at each sensor, will produce a locus of hyperbolas, with the probability that emitter is positioned on the intersection of these hyperbolas.

Elliptical Error Probable (EEP)

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14 Elliptical error probable and emitter position

EEP is an area where emitter is geometrically possible to be present. Based on projected AOAs, it is possible to determine 6 estimated emitter positions in blue colors and true emitter position in red color.

ERRORS IN THE ESTIMATION OF ERRORS IN THE ESTIMATION OF ERRORS IN THE ESTIMATION OF ERRORS IN THE ESTIMATION OF EMITTER POSITIONEMITTER POSITIONEMITTER POSITIONEMITTER POSITION

Errors in the System

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ERRORS IN THE ESTIMATION OF ERRORS IN THE ESTIMATION OF ERRORS IN THE ESTIMATION OF ERRORS IN THE ESTIMATION OF EMITTER POSITIONEMITTER POSITIONEMITTER POSITIONEMITTER POSITION 12th ICEPT

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Errors must be minimal in order to have accurate results. When errors affect the results, the system will generate inaccurate results, errors in the system were caused due to inherit errors from the system architecture or from the environment where the system is operating The true emitter location is the actual location of the emitter by theoretical computations while the estimated emitter location is the estimate of emitter location generated by this proposed algorithm.


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Gaussian noise was introduced to the x and y coordinates and computed the mean square distance (km) in the presence of this noise.

An illustration of the error plots in the x and y coordinates versus the noise error.


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Plot of the error in Range vs Distribution of noise when Gaussian noise was introduced to the x and y coordinates

The results obtained above were averaged for over 1000 iterations using Monte Carlo simulation. From the plots, it was noticed that the intensity of

the noise increases exponentially with the range distribution along the x and y coordinates.


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Bias plots of the system after the noise was introduced along the x and y coordinates


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The results obtained were also averaged for over 1000 iterations using the Monte Carlo simulation. From the plots, it was observed that the distortion in the accuracy of the estimation increases with the increase in the noise

intensity for both coordinates and the range.

� From the simulation analysis, it was observed that emitters were

statistically located at an area called EEP which is an area where

emitter is geometrically sited.

� Noise has been the major problem of signal processing; hence, various

sources of error were shown in plots.

� It was noticed that there was a linear relationship between the error in

the range and position error. This means that as the error increases

along the x and y coordinates, so is the error along the estimate

position increases and this leads to inaccuracy in the estimation.

� Increasing the number of receiving units would increase the accuracy

but with more ambiguities.

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CONCLUSIONCONCLUSIONCONCLUSIONCONCLUSION 12th ICEPT

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