FULL ACTIVE-PHASED-ARRAY MST (53 MHZ) RADAR

DETERMINATION OF CHARACTERISCS OF ATMOPSHERIC

TURBULENCE

Prof. SVS.JAYASYHAM1 and Y.Ramyasri2

1Professor, Department of ECE, S.V.Engineering college for women, Tirupati.

2Mtech, Department of ECE, S.V.Engineering college for women, Tirupati

1hod_ece@svew.edu.in, ramyasree2595@gmail.com

ABSTRACT:

The semi-active phased array

MST radar(32 by 32 Yagi-Uda antennae,

total 1024 antennae) operating at the

frequency of 53 MHz has been augmented

recently as fully-active phased array (FAPA)

Radar to study the atmospheric dynamics

and turbulence in detail. In this, receivers

were processed to determine the

characteristics of atmospheric turbulence

and its evolution in time could not be

studied. In the present case of FAPA, each

and every antenna is powered individually

with peak power of 1kW and a receiver

module is attached. With this facility, it can

be controlled the transmit beam pattern as

well as its pointing direction so that we

can space and time of atmospheric

turbulence can be studied. This review

paper discusses the generation, evolution

atmospheric turbulence of the FAPA system

and many digital receivers.

1. INTRODUCTION:

In fully-active phased array, each

and every antenna is powered individually

with peak power of 1kW and a receiver

module is attached. With this facility, it can

be controlled the transmit beam pattern as

well as its pointing direction so that a full

four dimensional characteristics (space and

time) of atmospheric turbulence can be

studied. The main aim of the present project

work is to study the generation, evolution

and dissipation mechanisms of atmospheric

turbulence and its imaging using multi

power-patterns of the FAPA system and

many digital receivers.

2. LITERATURE SURVEY

MST (MESOSPHERE STRATOSPHERE TROPOSPHERE) RADAR

International Journal of Research

Volume VIII, Issue VI, JUNE/2019

ISSN NO:2236-6124

Page No:2631

Mesosphere Stratosphere Troposphere, or

MST, Radar Technique was evolved from

the original work of Woodman and Guillen

in1974, which had proven to be powerful

means to explore the middle atmosphere

dynamics.

Determination of atmospheric turbulence by

MST

Radar technique requires the Radar system

be frequency coherent, that received signal

is compared with transmitted signal to retain

both the phase and amplitude of the returned

signals. Typical analysis procedures require

obtaining echo power spectrum. The results

of moments echo power spectrum yields the

echo power, mean Doppler shift and spectral

width.

METHODOLOGY:

Full Active-Phased-Array MST

(53 MHZ) RADARRadio Detection And Ranging

(RADAR) sends Electromagnetic (EM)

waves for collecting information about

distant targets and analysis the echo signals.

RADAR receives the characteristics of the

signal by determining the velocity and the

location of the target object. In atmospheric

science research, the radars emit pulse

modulated EM waveforms by using array of

antenna.

In the medium, refractive index

changes because of propagating

electromagnetic wave encounters. Changes

occur at the target region in electric property

which results in EM energy scatters in all

the directions.

The scattered energy which is

received back at the radar is known as back

scatter. Back scatter provides information

about the target region.

The radar derives basic information

of the target is parameters of target region

that are velocity and range. The distance of

the target from Radar is called as Range.

Due to back ground wind movement

velocity occurs.

The shift occurs in the carrier

frequency of the reflected wave due to

Doppler Effect is a measure of target’s

relative velocity. This is used to measure the

velocity of the moving target region.

Individual power supply is given to FAPA

so controlling of each element is easier.

Echoes which are obtained at height over

range of 1-1000km used by MST Radar and

this are used to study winds, waves,

turbulence and atmospheric stability. In the

world, turbulence is working constantly

International Journal of Research

Volume VIII, Issue VI, JUNE/2019

ISSN NO:2236-6124

Page No:2632

around us. Turbulence is the gusting winds

of the atmosphere.

Initially, echoes below 50 km

appear due to neutral turbulence but echoes

above 50 Km due to irregularities in the

electron density. Atmosphere density as well

as electron density at height range of 22-60

km is very low which results in very weak

echoes and gap region.

After collecting the information of

target object, then using atmospheric data

processor plot the MST Radar power

spectrum with Digital receiver also showing

the stacked power spectral plots of

atmosphere at height ranging from 1.50 km

to 26.85 km with 150 m height intervals.

By using Matlab R2008b plotted

power spectral density which represents the

Doppler shifted frequency and amplitude (8-

bit Radar echo strength) at height from 1.50

km upto 26.85 km of Zenith X. Collect the

first 5 peaks in height 1.50 km and then plot

that in one plane using Origin Pro 7.0. This

process continues considering all the

different heights (upto 26.85 km) which

were represented using Origin Pro 7.0. This

height from 1.5 km to 26.85 km in Origin

Pro 7.0 represents the generation and

evolution of atmospheric turbulence.

3.RESULTS ANALYSIS:

Figure 1: Power spectral plot of atmospherePlot of MST Radar power spectrum with Digital receiver and also shows plots of stacked power spectral at heights which ranges from 1.50 km to 26.85 km with an interval of height 150m.

The plot presents the Doppler shifted frequency with respective to each height Doppler shifted frequency in x-axis, Amplitude/Height in y-axis) which is nothing but the Radar output. Panel on the left represents the experiment parameters.

Figure 2: The radar output, power spectral density plot that represents target Doppler shift at height 1.50 km at Zenith X (Doppler shifted frequency in x-axis, Amplitude/Height in y-axis).

International Journal of Research

Volume VIII, Issue VI, JUNE/2019

ISSN NO:2236-6124

Page No:2633

Figure:3

Figure:4

Figure: 5

Figure:6

Figure:7

International Journal of Research

Volume VIII, Issue VI, JUNE/2019

ISSN NO:2236-6124

Page No:2634

Figure:8

Figure:9

Figure 3,4,5,6,7,8,9 : MST Radar power spectrum turbulence at different heights at zenith X

4. CONCLUSION

Fully Active phased array MST radar

is advanced technology of MST radar. In

this radar, by using optical cables, data loss

can be reduced and also it requires very low

power to operate it. As we use Transmitter

modules near the antenna which results in

the less number of cables are used. Due to

Fully Active phased array concept, beam

steering is possible to receive echo signals in

all directions.

5. REFERENCES1. Balley, B, B., and K.S.Gage, The

MST radar technique: Potential for

middle atmospheric Studies, Pure

Appl. Geophys., 118, 452-93, 1980.

2. Chakravarty, T., S H Damle, J. V.

Chande. S Hadle, K. P. Ray, and A.

Kollani, Calibration of ST radar

using radio source Vigro – A Indian

J.Rao Space Phys., 22, 103-10, 1993.

3. Ecklud, W. L. K. S Gage, B. B,

Balsley. R. G. Strauch and J. L,

Green, vertical wind variability

observed by VHP radar in the lee of

the Colorado Roches, Mon, weather

Rev., 1l0, 1451 - 1457, 1982.

International Journal of Research

Volume VIII, Issue VI, JUNE/2019

ISSN NO:2236-6124

Page No:2635