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
[email protected], [email protected]
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).
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Volume VIII, Issue VI, JUNE/2019
ISSN NO:2236-6124
Page No:2633
Figure:3
Figure:4
Figure: 5
Figure:6
Figure:7
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Volume VIII, Issue VI, JUNE/2019
ISSN NO:2236-6124
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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.
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Volume VIII, Issue VI, JUNE/2019
ISSN NO:2236-6124
Page No:2635