Millimeter-Wave Radars for Environmental Studies
A review is given of recent activities undertaken in the Institute of Radio Astronomy of the National Academy of Sciences of Ukraine for the development of millimeter-wave radars. The radars constructed include cloud radars and a side-looking airborne radar system. They are capable to perform real-t...
Saved in:
| Date: | 2002 |
|---|---|
| Main Authors: | , , , , , , , |
| Format: | Article |
| Language: | English |
| Published: |
Радіоастрономічний інститут НАН України
2002
|
| Series: | Радиофизика и радиоастрономия |
| Online Access: | https://nasplib.isofts.kiev.ua/handle/123456789/122308 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| Journal Title: | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| Cite this: | Millimeter-Wave Radars for Environmental Studies / D.M. Vavriv, V.A. Volkov, V.N. Bormotov, V.V. Vynogradov, R.V. Kozhyn, B.V. Trush, A.A. Belikov, V.Ye. Semenyuta // Радиофизика и радиоастрономия. — 2002. — Т. 7, № 2. — С. 121-138. — Бібліогр.: 26 назв. — англ. |
Institution
Digital Library of Periodicals of National Academy of Sciences of Ukraine| id |
nasplib_isofts_kiev_ua-123456789-122308 |
|---|---|
| record_format |
dspace |
| spelling |
nasplib_isofts_kiev_ua-123456789-1223082025-02-10T00:47:45Z Millimeter-Wave Radars for Environmental Studies Радиолокаторы миллиметрового диапазона длин волн для исследования параметров окружающей среды Радіолокатори міліметрового діапазону довжин хвиль для дослідження параметрів навколишнього середовища Vavriv, D.M. Volkov, V.A. Bormotov, V.N. Vynogradov, V.V. Kozhyn, R.V. Trush, B.V. Belikov, A.A. Semenyuta, V.Ye. A review is given of recent activities undertaken in the Institute of Radio Astronomy of the National Academy of Sciences of Ukraine for the development of millimeter-wave radars. The radars constructed include cloud radars and a side-looking airborne radar system. They are capable to perform real-time, high-resolution measurements in the frequency bands of 36 and 95 GHz. The setup of these instruments, the novel technical solutions, and the signal processing technique introduced are discussed. The results obtained with such instruments during measurement campaigns are presented as well. В статье обобщены результаты работ, инициированных в последнее время в Радиоастрономическом институте НАН Украины, по созданию радиолокаторов миллиметрового диапазона длин волн. Разработанные радиолокационные системы включают метеорологические локаторы и самолетный радиолокатор бокового обзора. Они дают возможность проведения измерений в 8- и 3-мм диапазонах длин волн с высоким пространственным разрешением в реальном времени. В статье обсуждаются вопросы построения этих инструментов, использованные новые технические решения и методы обработки сигналов. Представлены также результаты проведенных измерений. У статті узагальнені результати робіт, ініційованих останнім часом у Радіоастрономічному інституті НАН України, по створенню радіолокаторів міліметрового діапазону довжин хвиль. Розроблені радіолокаційні системи включають метеорологічні локатори і літаковий радіолокатор бічного огляду. Вони дають можливість проведення вимірювань у 8- і 3-мм діапазонах довжин хвиль з високим просторовим розділенням у реальному часі. У статті обговорюються питання побудови цих інструментів, використані нові технічні рішення і методи обробки сигналів. Представлено також результати проведених вимірювань. The authors would like to thank all of their colleagues at the Department of Microwave Electronics of the Institute of Radio Astronomy for their effort in the development of the cloud radars. The helpful cooperation with Dr. V. I. Kazantsev, Prof. B. A. Rozanov, Dr. A. C. Kurekin, and A. S. Gavrilenko is appreciated. The authors are indebted to Prof. L. Lytvynenko, Prof. K. Schünemann, and Dr. G. Peters for fruitful discussions and support. 2002 Article Millimeter-Wave Radars for Environmental Studies / D.M. Vavriv, V.A. Volkov, V.N. Bormotov, V.V. Vynogradov, R.V. Kozhyn, B.V. Trush, A.A. Belikov, V.Ye. Semenyuta // Радиофизика и радиоастрономия. — 2002. — Т. 7, № 2. — С. 121-138. — Бібліогр.: 26 назв. — англ. 1027-9636 https://nasplib.isofts.kiev.ua/handle/123456789/122308 en Радиофизика и радиоастрономия application/pdf Радіоастрономічний інститут НАН України |
| institution |
Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| collection |
DSpace DC |
| language |
English |
| description |
A review is given of recent activities undertaken in the Institute of Radio Astronomy of the National Academy of Sciences of Ukraine for the development of millimeter-wave radars. The radars constructed include cloud radars and a side-looking airborne radar system. They are capable to perform real-time, high-resolution measurements in the frequency bands of 36 and 95 GHz. The setup of these instruments, the novel technical solutions, and the signal processing technique introduced are discussed. The results obtained with such instruments during measurement campaigns are presented as well. |
| format |
Article |
| author |
Vavriv, D.M. Volkov, V.A. Bormotov, V.N. Vynogradov, V.V. Kozhyn, R.V. Trush, B.V. Belikov, A.A. Semenyuta, V.Ye. |
| spellingShingle |
Vavriv, D.M. Volkov, V.A. Bormotov, V.N. Vynogradov, V.V. Kozhyn, R.V. Trush, B.V. Belikov, A.A. Semenyuta, V.Ye. Millimeter-Wave Radars for Environmental Studies Радиофизика и радиоастрономия |
| author_facet |
Vavriv, D.M. Volkov, V.A. Bormotov, V.N. Vynogradov, V.V. Kozhyn, R.V. Trush, B.V. Belikov, A.A. Semenyuta, V.Ye. |
| author_sort |
Vavriv, D.M. |
| title |
Millimeter-Wave Radars for Environmental Studies |
| title_short |
Millimeter-Wave Radars for Environmental Studies |
| title_full |
Millimeter-Wave Radars for Environmental Studies |
| title_fullStr |
Millimeter-Wave Radars for Environmental Studies |
| title_full_unstemmed |
Millimeter-Wave Radars for Environmental Studies |
| title_sort |
millimeter-wave radars for environmental studies |
| publisher |
Радіоастрономічний інститут НАН України |
| publishDate |
2002 |
| url |
https://nasplib.isofts.kiev.ua/handle/123456789/122308 |
| citation_txt |
Millimeter-Wave Radars for Environmental Studies / D.M. Vavriv, V.A. Volkov, V.N. Bormotov, V.V. Vynogradov, R.V. Kozhyn, B.V. Trush, A.A. Belikov, V.Ye. Semenyuta // Радиофизика и радиоастрономия. — 2002. — Т. 7, № 2. — С. 121-138. — Бібліогр.: 26 назв. — англ. |
| series |
Радиофизика и радиоастрономия |
| work_keys_str_mv |
AT vavrivdm millimeterwaveradarsforenvironmentalstudies AT volkovva millimeterwaveradarsforenvironmentalstudies AT bormotovvn millimeterwaveradarsforenvironmentalstudies AT vynogradovvv millimeterwaveradarsforenvironmentalstudies AT kozhynrv millimeterwaveradarsforenvironmentalstudies AT trushbv millimeterwaveradarsforenvironmentalstudies AT belikovaa millimeterwaveradarsforenvironmentalstudies AT semenyutavye millimeterwaveradarsforenvironmentalstudies AT vavrivdm radiolokatorymillimetrovogodiapazonadlinvolndlâissledovaniâparametrovokružaûŝeisredy AT volkovva radiolokatorymillimetrovogodiapazonadlinvolndlâissledovaniâparametrovokružaûŝeisredy AT bormotovvn radiolokatorymillimetrovogodiapazonadlinvolndlâissledovaniâparametrovokružaûŝeisredy AT vynogradovvv radiolokatorymillimetrovogodiapazonadlinvolndlâissledovaniâparametrovokružaûŝeisredy AT kozhynrv radiolokatorymillimetrovogodiapazonadlinvolndlâissledovaniâparametrovokružaûŝeisredy AT trushbv radiolokatorymillimetrovogodiapazonadlinvolndlâissledovaniâparametrovokružaûŝeisredy AT belikovaa radiolokatorymillimetrovogodiapazonadlinvolndlâissledovaniâparametrovokružaûŝeisredy AT semenyutavye radiolokatorymillimetrovogodiapazonadlinvolndlâissledovaniâparametrovokružaûŝeisredy AT vavrivdm radíolokatorimílímetrovogodíapazonudovžinhvilʹdlâdoslídžennâparametrívnavkolišnʹogoseredoviŝa AT volkovva radíolokatorimílímetrovogodíapazonudovžinhvilʹdlâdoslídžennâparametrívnavkolišnʹogoseredoviŝa AT bormotovvn radíolokatorimílímetrovogodíapazonudovžinhvilʹdlâdoslídžennâparametrívnavkolišnʹogoseredoviŝa AT vynogradovvv radíolokatorimílímetrovogodíapazonudovžinhvilʹdlâdoslídžennâparametrívnavkolišnʹogoseredoviŝa AT kozhynrv radíolokatorimílímetrovogodíapazonudovžinhvilʹdlâdoslídžennâparametrívnavkolišnʹogoseredoviŝa AT trushbv radíolokatorimílímetrovogodíapazonudovžinhvilʹdlâdoslídžennâparametrívnavkolišnʹogoseredoviŝa AT belikovaa radíolokatorimílímetrovogodíapazonudovžinhvilʹdlâdoslídžennâparametrívnavkolišnʹogoseredoviŝa AT semenyutavye radíolokatorimílímetrovogodíapazonudovžinhvilʹdlâdoslídžennâparametrívnavkolišnʹogoseredoviŝa |
| first_indexed |
2025-12-02T06:47:30Z |
| last_indexed |
2025-12-02T06:47:30Z |
| _version_ |
1850378080072237056 |
| fulltext |
Ðàäèîôèçèêà è ðàäèîàñòðîíîìèÿ, 2002, ò. 7, ¹2, ñ. 121-138
© D. M. Vavriv, V. A. Volkov, V. N. Bormotov, V. V. Vynogradov, R. V. Kozhyn, B. V. Trush, A. A. Belikov, and V. Ye. Semenyuta, 2002
Millimeter-Wave Radars for Environmental Studies
D. M. Vavriv, V. A. Volkov, V. N. Bormotov, V. V. Vynogradov, R. V. Kozhyn,
B. V. Trush, A. A. Belikov, and V. Ye. Semenyuta
Institute of Radio Astronomy of the National Academy of Sciences of Ukraine
4, Chervonopraporna St., 61002, Kharkov, Ukraine
E-mail: vavriv@rian.kharkov.ua
Received January 16, 2002
A review is given of recent activities undertaken in the Institute of Radio Astronomy of the
National Academy of Sciences of Ukraine for the development of millimeter-wave radars. The radars
constructed include cloud radars and a side-looking airborne radar system. They are capable to
perform real-time, high-resolution measurements in the frequency bands of 36 and 95 GHz. The set-
up of these instruments, the novel technical solutions, and the signal processing technique introduced
are discussed. The results obtained with such instruments during measurement campaigns are pre-
sented as well.
1. Introduction
During the last five years in the Institute of
Radio Astronomy several R&D projects have
been fulfilled aimed at the development of mm-
wave radars for environmental studies. In partic-
ular, we have constructed 95 and 36 GHz cloud
radars and a dual-frequency (95 and 36 GHz)
airborne side-looking radar.
Millimeter-wave Doppler radars are consid-
ered now as the most actual instruments for per-
manent monitoring and investigations of clouds.
An idea of using cloud radars at millimeter wave-
lengths is based on the fact that the power of
radar returns from cloud particles scales as 4−λ
( λ is the wavelength) almost up to the wave-
length of 3 mm. Therefore, both a high radar sen-
sitivity and resolution can be achieved by using
the radar transmitters with a relatively low out-
put power and the antenna systems with moder-
ate dimensions, as compared to those at lower
frequencies. The above advantages enable the
development of compact and transportable cloud
radar systems. Another advantage of the milli-
meter-waves is related with a negligible role of
reflections caused by the clear air turbulence.
Such reflections manifest themselves substantially
in radar returns at larger wavelengths, leading to
a serious problem of identification of signals pro-
duced purely by the cloud particles.
The millimeter-wave cloud radars are typically
produced to operate at the frequencies of about
36 and 95 GHz, which correspond to the atmo-
spheric low-loss windows. The 36 GHz frequency
band is considered now as the most suitable band
for the development of ground-based radars, where-
as 95 GHz radars have obvious advantages for per-
forming observations from aircraft. However, com-
bined observations at both these frequencies are
rather promising. They allow to find the cloud
particle size and velocity distributions, the water
content, and other cloud parameters.
Until the beginning of the 90th, millimeter-
wave cloud radars were available only at sever-
al institutions around the world, and they were
used as laboratory instruments for non-regular
cloud observations [1-3]. During the last decade,
there are growing activities related both with
the development and applications of the milli-
meter-wave radar systems [4-7]. Such activities
have been stimulated by several international
programs aimed at investigating the global cli-
mate change. It is believed that by means of such
cloud radars it would be possible to investigate
and understand in details the macro- and micro-
physical properties of clouds and their impact
D. M. Vavriv, V. A. Volkov, V. N. Bormotov, V. V. Vynogradov, R. V. Kozhyn, B. V. Trush, A. A. Belikov, and V. Ye. Semenyuta
122 Ðàäèîôèçèêà è ðàäèîàñòðîíîìèÿ, 2002, ò.7, ¹2
on the Earth radiation budget and the hydrolog-
ical cycle.
Nowadays cloud radar systems with a high
sensitivity are required to study even rather weak
and thin cloud layers. Such systems should be
capable for long-term, unattainable operation and
real-time, high-resolution measurements of vari-
ous atmospheric characteristics, like profiles of
radar reflectivity, Doppler spectrum and its mo-
ments, and polarimetric quantities. Besides, the
radars should include a reliable system of perma-
nent calibration, a possibility of a remote con-
trol, and a possibility of an access to radar data
through a network. The cloud radars developed
and produced in our institute [8-10] satisfy these
requirements to a great extent.
The side-looking airborne radar [11], which
will be also described in this paper, is used for
the investigation of the radar scattering proper-
ties of various surfaces at the frequencies of
36 and 95 GHz simultaneously. At the first stage
of exploitation, the radar system has been used
for the study of millimeter-wave backscatter
characteristics of water surfaces in the presence
of oil films. This study has been aimed at the
development of efficient instruments and meth-
ods for oil-spill detection and quantification.
There are two main reasons for the application
of millimeter waves rather than microwaves
when developing instruments for oil pollution
monitoring. Firstly, so far accumulated experi-
mental data [12, 13] and recent theoretical re-
sults [14] indicate that radar contrast of the films
becomes larger with increasing the radar oper-
ating frequency. Secondly, millimeter wave sys-
tems offer the well-known weight and portabil-
ity advantages, what make their installation on
a light-weight aircraft easy.
The above radar systems are described in this
paper which is organized in the following way. In
Section 2, general approaches and solutions to
the development of the transmitters and the data
acquisition system used in the both types of ra-
dars, are described. In Section 3, the 36 Doppler
cloud radar is described along with examples of
measurement results. The 95 GHz Doppler cloud
radar is presented in Section 4. Section 5 con-
tains a description of the dual-frequency side-
looking radar and an example of its application
for oil-spill detection. Section 6 contains a brief
summary of this paper.
2. Radar Design Solutions
2.1. Radar Ttransmitters
Usually, the choice of reliable high-power
tubes for 36 and 95 GHz radar transmitters pre-
sents the most serious problem when developing
the mm-wave radars with a long-distance opera-
tion range. The problem lies in the necessity to
have the transmitters which should provide both
a high peak and average power in order to achieve
a high radar sensitivity and spatial resolution si-
multaneously. The transmitters for 36 GHz ra-
dars are usually based on conventional magne-
trons or travelling-wave tubes (TWT). The mag-
netron transmitters, however, often suffer from a
low reliability of conventional magnetrons for this
frequency band [7]. The application of TWTs
makes it necessary to use a pulse compression
technique, since such tubes have typically a low
level of the peak power, but they can operate with
a high value of the duty factor [7]. Until recently,
transmitters for 95 GHz radars have been mainly
built on the basis of the klystron with extended
interaction [4, 6]. This klystron surpasses the other
tubes suitable for such radars in the average power
provided, the dimensions, and the weight.
We have used an alternative way of develop-
ing both the 36 and 95 GHz radar transmitters.
Our transmitters are based on spatial-harmonic
magnetrons with cold secondary-emission cath-
ode [15-17], which are produced in our institute.
Compared with the classical magnetrons, such
magnetrons can operate effectively at these fre-
quencies and even at higher ones. Besides, they
are characterized by smaller dimensions and
weight, higher peak and averaged output power,
and larger lifetime while maintaining other well-
known advantages of magnetron tubes.
Our studies have shown that using specially
designed modulator enables the development of
transmitters with a rather high quality of output
pulses [18, 19]. We have found that among vari-
ous possible schemes of modulators, the scheme
with partial discharge of the storage capacitor and
a hard tube as high voltage switch is most suit-
Millimeter-Wave Radars for Environmental Studies
123Ðàäèîôèçèêà è ðàäèîàñòðîíîìèÿ, 2002, ò. 7, ¹2
able for driving both the 36 and 95 GHz spatial-
harmonic magnetrons with cold cathode. The typ-
ical transmitter block diagram is shown in Fig. 1.
The transmitter usually includes the following
main parts: a high-voltage power supply, filament
power supplies for the magnetron and the modu-
lator tube, a driver for this tube, and a controller.
The low-voltage power supplies were built by
using a resonant technique to provide high effi-
ciency and to suppress interference. The high
power supply utilizes a flyback converter with a
current feedback along with a voltage multiplier.
Such scheme allows one to obtain a voltage rip-
ple as low as 2 V with an output voltage of 20 kV
and an output power of 500 W. The output stage
of the hard tube driver is based on the two-pole
scheme and provides a voltage swing of 1500 V
with the rise and fall times less than 15 ns. All
power supplies in the modulator are synchronized
at the frequencies which are a multiple of the
pulse repetition frequency of the transmitter.
The operation of the transmitters is controlled
by a microprocessor, which provides a smart mode
of transmitter operation and a possibility of the
transmitter diagnostics. In particular, pulse-to-
pulse programmable control of the pulse repeti-
tion frequency is introduced. Local and remote
control of the transmitters are made possible.
The above solutions enabled us to obtain the
output transmitter pulses of a rather good shape
and with a negligibly small jitter. The intrapulse
phase change during the high power period of the
200 ns pulses is about 10° and 20 ,° and the pulse-
to-pulse frequency chirp is reproducible to about
100 Hz and 300 Hz for the 36 and 95 GHz trans-
mitters, respectively. The pulse jitter is less than
2 ns. The jitter occurs only at the initial stage of
the pulse formation.
In order to illustrate the high quality of mag-
netron transmitters introduced in a 36 GHz radar
system, a Doppler spectrum from a stationary
ground based target at 12 km is shown in Fig. 2.
A dwell time of 0.1 s and a pulse repetition fre-
quency of 5 kHz were used in the measurements.
It appeared that the width of the spectrum around
zero frequency is 10 Hz at the level �5 dB and
20 Hz at the level � 45 dB, and it is determined
by the dwell time rather than by the phase insta-
Fig. 1. Typical block-diagram of the radar transmitters
D. M. Vavriv, V. A. Volkov, V. N. Bormotov, V. V. Vynogradov, R. V. Kozhyn, B. V. Trush, A. A. Belikov, and V. Ye. Semenyuta
124 Ðàäèîôèçèêà è ðàäèîàñòðîíîìèÿ, 2002, ò.7, ¹2
bilities of the transmitted pulses. It is also seen
from this figure that the power density in the vi-
cinity of zero frequency is about 50 dB higher
compared to that in other spectral components.
The achieved high quality of output pulses of
the transmitters predetermined the application of
a coherent on receiver technique for the realiza-
tion of Doppler spectrum measurements.
2.2. Data Acquisition System
Modern radars for environmental studies are
multipurpose and complicated instruments. This
calls for the development of corresponding hard-
ware and software to provide real-time signal
processing, representation, and storing of the ra-
dar data. Recent advances in programmable dig-
ital signal processors (DSP) together with novel
approaches in signal processing and program-
ming techniques allow the development of a cost-
effective, universal data acquisition system with
a wide range of application. We have developed
such data acquisition system [20], which have
been successfully implemented in both the side-
looking dual frequency radar and the cloud ra-
dar systems.
The elaborated data acquisition system in-
cludes the following main components and cor-
responding software: (i) pre-processing board
with a DSP, flash programming gate array
(FPGA), and A/D converters; (ii) routines for
DSP, providing input and performing prelimi-
nary processing of data; (iii) software package
installed on a host computer performing inter-
face between all the DSP on the ISA or PCI
busses, reading preliminary processed and com-
pressed data from the DSP, and performing oth-
er necessary functions (see below).
The main problem in the development of the
pre-processing board lies in the necessity to re-
ceive, process, and compress a large input stream
of data and service information in a real-time
operation mode. For example, in the case of the
dual-frequency side-looking radar, the input data
stream is about 40 Mbytes per second under the
pulse repetition frequency of 5 kHz. This prob-
lem is effectively solved with the help of a com-
bination of hardware and software signal pro-
cessing in the board as illustrated in Fig. 3. The
board provides also interface with radar trans-
mitters and receivers. So, there are two chan-
nels, each of them consisting of an input ampli-
fier with a level shift circuit and ADCs. In order
to provide a fast time-variant gain control of the
receivers, a 40 MHz, 10-bit DAC is introduced.
There is also a 5 kHz, 8-bit DAC for manual
control of the gain of the receivers. The board
contains also a buffer RAM, a serial port inter-
face, control and synchronization circuits, to-
gether with DSP and ISA or PCI bus interface.
The receiver quadrature outputs come into the
ADC input. The sampling rate is typically 50 MHz
with the resolution of 12 bit. The digitized sig-
nals are written into one of the RAM buffers.
The presence of two buffers allows to minimize
time losses and to organize an optimal data pro-
cessing. The generation of control and synchro-
nization signals is performed in the RAM syn-
chronization and control module based on the
FPGA. There is a serial port, which allows to
receive and transmit signals from/to up to
32 external sensors or sub-systems, like gyroscop-
ic sensor, altimeter, etc. The interface of the pre-
processing board with the host computer is ar-
ranged through standard ISA or PCI busses. Par-
allel synchronous operation of several such boards
is possible in the host computer.
A software package has been developed for
the host computer to perform the final stage of
Fig. 2. Doppler spectrum from a stationary ground
based target at a distance 12 km obtained with a
36 GHz Doppler radar
Millimeter-Wave Radars for Environmental Studies
125Ðàäèîôèçèêà è ðàäèîàñòðîíîìèÿ, 2002, ò. 7, ¹2
the radar data processing. The package consists
of the main program, which provides the user
interface of the host computer and the interaction
between other external devices; the library of
additional functions performing the control of
external devices (e. g., GPS receiver and aircraft
orientation system connected to the computer
through its serial ports); the virtual device driver
performing the correct operation of the central
processor and ISA or PCI cards in multitask op-
erating system. In addition to the data processing
and displaying, the package performs an inde-
pendent control of the radar data channels (re-
ceiver TVGC, preliminary data processing, etc.).
The controls are independent with respect to the
real time data processing. This possibility can be
realized only if the host processor operates under
a multitask operating system. For this purpose
we used OS Windows�98, NT, 2000, and Linux.
A block diagram of the software package and its
interaction with the hardware is presented in Fig.
4. Generally, the program represents a 32-bit mul-
tithread application. There are several reasons
using the multithread approach. Firstly, the data
from both pre-processing boards and serial ports
of the host computer come asynchronously rela-
tive to the main program (i. e., by hardware inter-
rupts). Then one can understand that a one-thread
program cannot use the processor time optimally.
Secondly, it is necessary to process radar data as
well as to control both processing channels inde-
pendently. In this case, the multithread approach
together with thread synchronization tools, data
buffering and object programming facilitate dras-
tically the global architecture and debugging of
the program. The data flows between the data
processing software threads are shown in Fig. 4 by
thick solid lines with arrows. The transfer roads of
the control and the service information between
the software modules are shown by solid lines and
thick dashed lines with arrows, respectively. Thread
1a,b and Thread 3a,b have maximal time-critical
priority. Thread 2 and Thread 4 are common for
both radar data processing channels. Thread 4 is
the main application thread. This thread provides
the user interface, so it starts automatically after
the program start. The user interface provides the
option of a desired preliminary data processing
routine. The user interface allows the operator to
change preliminary data processing parameters
(say, type of the TVGC function, slow or manual
GC values, type and sizes of the averaging win-
dows, etc.) without interrupting the real time sig-
nal processing. The operator can change the pa-
rameters determining the operation modes of
Thread 3a,b performing the main data process-
Fig. 3. Combination of hardware and software signal processing in the board of the dual frequency radar
D. M. Vavriv, V. A. Volkov, V. N. Bormotov, V. V. Vynogradov, R. V. Kozhyn, B. V. Trush, A. A. Belikov, and V. Ye. Semenyuta
126 Ðàäèîôèçèêà è ðàäèîàñòðîíîìèÿ, 2002, ò.7, ¹2
ing. For example, it is possible to change dis-
playing parameters, namely the size, scale and
the colour palette of radar image, the service in-
formation display parameters, the switch on and
off data saving on HDD, etc. The software al-
lows to browse and display radar data files saved
before. A lot of additional service options for the
data displaying analysis are available in the brows-
ing/displaying regime.
3. 36 GHz Doppler Cloud Radar
3.1. Radar Characteristics
The 36 GHz Doppler cloud radar to be de-
scribed in this section was developed and pro-
duced in cooperation with Meteorologische
Messtechnik GmbH, Elmshorn, Germany, during
2000. The radar was designed for unattended
long-term operation to provide real-time perma-
nent measurements of vertical profiles of the re-
flectivity, the mean velocity, the velocity vari-
ance, and the velocity spectrum. The possibility
of raw data saving is also introduced. A perma-
nent calibration system is included in the radar.
The radar contains a server to provide remote
control and data receiving.
Radar measurements are performed with the
characteristics listed in Table 1. Corresponding
characteristics of the 95 GHz Doppler radar,
which will be described in Section IV, are also
given in this table. The main technical parame-
ters of the both radars are given in Table 2.
Fig. 4. A block diagram of the software package and its interaction with the hardware of the dual frequency radar
Millimeter-Wave Radars for Environmental Studies
127Ðàäèîôèçèêà è ðàäèîàñòðîíîìèÿ, 2002, ò. 7, ¹2
A block-diagram of the 36 GHz radar is
shown in Fig. 5. The radar includes the follow-
ing principal systems: an antenna system, a trans-
mitter-receiver switch, two transmitters, one of
which is used as a back-up transmitter, a receiv-
er, a calibration system, a radar controller, a data
acquisition and signal processing system, and a
host computer. In addition, the radar has a
waveguide ventilation system (not indicated in
Fig. 5). The transmitter-receiver switch, the
transmitters, the receiver, the calibration system,
and the radar controller are placed in a transmit-
ter-receiver rack (TRR), which is shown in Fig. 6
together with the radar antenna. During experi-
Table 1. Radar measurement characteristics
36 GHz radar 96 GHz
Minimum height, m 200 200
Measuring range, km 15 15
Range resolution, m 15 � 60 7.5 � 60
Doppler velocity resolution, m/s 0.05 0. 1
Maximum unambiguous velocity, m/s ±15 ±3.5
Number of Gates (max) 500 256
FFT length 128, 256, and 512 256 and 512
Minimum dwell time, s 0.1 0.1
Antenna beam width, degree 0.6 0.4
Number of gates with simultaneous stored raw data 8 2
Sensitivity at 5 km with the integration time of 0.1 s, dBZ �41 �41
Table 2. Technical parameters of the 36 GHz and 95 GHz cloud radars
36 GHz radar 95 GHz radar
Peak power (max), kW 30 4
Pulse width, ns 100 � 400 50 � 400
Pulse repetition frequency, kHz 2.5, 5, and 7.5 2.5 and 5
Minimum detectable signal, dBm �104 �100
Sampling rate, MHz 50 20
Sampling resolution, bit 12 12
Type of bus for the signal processing board PCI ISA
Operation system of the host computer Linux or Windows Windows
Network protocol TCP/IP
Antenna diameter, m 1 0.5
Antenna sidelobe level, dB �20 �20
Power supply 230V ± 10 % AC 230V ± 10 % AC
Watt consumption (max), kW 1300 700
Weight, kg 140 60
D. M. Vavriv, V. A. Volkov, V. N. Bormotov, V. V. Vynogradov, R. V. Kozhyn, B. V. Trush, A. A. Belikov, and V. Ye. Semenyuta
128 Ðàäèîôèçèêà è ðàäèîàñòðîíîìèÿ, 2002, ò.7, ¹2
ments, the radar is typically placed in a car trail-
er. This allows to use it at remote locations at
any weather conditions.
Recent advances in millimeter wave compo-
nents, circuit design, and programming technique
were implemented in the radar hardware and soft-
ware. A Cassegrainian antenna with a 1-meter
parabolic dish of 540 mm focal length is used.
The antenna gain is 50 dB. The cross-polariza-
tion decoupling is better than � 40 dB. A corru-
gated horn with a 30° -mouth is used as the illu-
minator. The illuminator is protected from rain
and dust by a Teflon cap. Holes are made in the
antenna dish to evacuate water during rain. The
antenna is lodged on a chassis, which enables
pointing the antenna at any desirable angle.
The receiver was built by using only single
frequency conversion to minimize the overall
phase noise. The realization of such scheme be-
came possible due to the introduction of a low
noise synthesizer operating in the frequency band
of 36 � 37 GHz and having the frequency step as
low as 100 kHz. The receiver also benefits from
the application of a mixer with a 3.5 dB noise
figure and a 25 dB suppression of the local os-
cillator signal. A novel digital automatic frequen-
cy control loop is introduced to keep the differ-
ence between the magnetron and coherent oscil-
lator frequencies less than 100 kHz with a high
stability.
A digital coherence on receiver technique
is realized. The phase of each transmitted pulse
is stored directly in the digital signal processor
and compared with the phase of reflected sig-
nal to calculate the Doppler velocity spectrum
and its moments. The spectrum and the spec-
trum moments are measured simultaneously for
500 gates.
Fig. 5. A block-diagram of the 36 GHz radar
Millimeter-Wave Radars for Environmental Studies
129Ðàäèîôèçèêà è ðàäèîàñòðîíîìèÿ, 2002, ò. 7, ¹2
The availability of a comprehensive control
and diagnostic system is an important feature of
this radar. The transmitters and receiver have their
own controllers, which provide their programma-
ble operation and a possibility of local and re-
mote control and diagnostics. Totally, 29 radar
parameters are controlled in real time, and the
values of these parameters are stored in log-files,
that simplifies essentially radar troubleshooting.
Simultaneously, the controllers provide a safe
radar operation by automatically controlling the
radar parameters and switching off the radar in
the case of dangerous situations.
The radar has a built-in permanent calibra-
tion system. The radar calibration is based on
the independent measurements of the transmit-
ter and receiver parameters. For these purposes,
the transmitter output power and receiver sensi-
tivity are continuously measured. The receiver
sensitivity is determined by means of measure-
ments of the signal to noise ratio of an addition-
al signal with a constant power level. Such cal-
ibration system also enables evaluating the an-
tenna surface conditions.
The radar has network capabilities allowing
remote radar control and data receiving through
any network supporting the TCP/IP protocol, in-
cluding the Internet. In order to provide the net-
work services, a special radar server is developed
and introduced [21]. The server is working on
the radar host computer under control of the Linux
operating system. There is also a software pack-
age of Windows programs for obtaining and vi-
sualising radar data via the Internet. Remote con-
trol and diagnostics of the radar operation from
any network computer is made possible as well.
The measured quantities, namely the reflec-
tivity and velocity profiles, the velocity variance,
and the Doppler spectrum are accessible in real
time in various graphical and map forms on user
displays of local and remote users. There are three
levels of access to the radar. The first level, which
is the level of the highest priority, includes a low
level control and diagnostics of the whole radar
system with a possibility to modify any radar
parameters, including the internal parameters of
the radar units. Such access is allowed only for
qualified technical personnel. The second level
of the radar control includes both local and re-
mote high level control of radar operation, signal
processing, data displaying, and data storing.
Local and remote receiving of radar data and
control of the mode of data displaying are made
possible at the third level.
The user interface with the radar is organized
as four display pages with corresponding menus.
Each page forms a specific group of control ele-
ments: The first page, named DSP control, is used
to control the DSP of the preprocessing card. The
second page, named Radar control, is introduced
to control the transmitter and receiver operation.
The third page, named Processing control, is used
to control the modes of row data processing, in-
cluding data storage. The fourth page, named
Image control, is for controlling the modes and
parameters of the processed data viewing.
Example of configuration of the Image con-
trol page on the user display is shown in Fig. 7.
The page includes a control panel and a data
Fig. 6. Transmitter-receiver rack together with the
radar antenna
D. M. Vavriv, V. A. Volkov, V. N. Bormotov, V. V. Vynogradov, R. V. Kozhyn, B. V. Trush, A. A. Belikov, and V. Ye. Semenyuta
130 Ðàäèîôèçèêà è ðàäèîàñòðîíîìèÿ, 2002, ò.7, ¹2
image panel. The control panel allows control-
ling radar operation in real time. On the data
image panel, there are the intensity, velocity,
variance, and the spectrum windows. Each of
these four windows is divided into two subwin-
dows. The upper part reflects the height-time
map of the intensity, velocity, and variance in
the case of the intensity, velocity, and variance
windows, respectively. The lower part of these
windows shows the instant oscilloscope plots of
the incoming data. The instant oscilloscope plots
can display either the horizontal or the vertical
cut of the upper maps. For example, such cut
may show the intensity versus time at some se-
lected height (horizontal plot), or the intensity
versus height (vertical plot). The upper plot of
the spectrum window is the dynamical spectrum,
where the vertical axis corresponds to the time
and horizontal one to the Doppler frequency (or
the corresponding velocity). The lower plot is
an instant spectrum. Any of these windows may
be temporarily hidden.
3.2. Examples of Measurements
Typical examples of radar images of various
types of clouds obtained with the 36 GHz cloud
radar are presented in Fig. 8, 9, and 10. These
figures show the vertical profiles of the reflec-
tivity in terms of dBZ (left column) and the mean
velocity (right column) in a time-height repre-
sentation. The horizontal axes show the time in
seconds, and the vertical ones show the height
in meters.
In Fig. 8 cirrus clouds are shown. The base of
such clouds is typically more than 6 km. In this
case, the clouds occupy the layer from 6.5 km to
about 11 km. From the velocity data, one can
find the regions where the cloud particles are
moving mainly in the up- and downward direc-
tions. However, the maximum velocities is less
than 1 m/s. Notably higher particle velocities are
seen inside the middle- and low-layer clouds
shown in Fig. 9. These two types of clouds are
clearly separated in space. The low-layer clouds
are precipitating, but the precipitation does not
Fig. 7. Example of configuration of the radar user display
Millimeter-Wave Radars for Environmental Studies
131Ðàäèîôèçèêà è ðàäèîàñòðîíîìèÿ, 2002, ò. 7, ¹2
reach the ground in this case. The latter takes
place in Fig. 10, where a heavy rain situation is
illustrated.
Reflections from the atmospheric boundary
layer can be seen in Fig. 8 and 9. Such reflections
exist under the conditions of the clear air atmosphere
and arrive from the heights up to about 2 km.
A great deal of experimental data has already
been accumulated and some general properties
of the reflections have been determined [22-24].
For example, it has been found that: (i) the re-
flections are from closely spaced scatterers, (ii)
the maximum scattering activity occurs in the
noon and the minimum is at night, and (iii) in
Fig. 8. Cirrus clouds
Fig. 9. Middle and low layer clouds
Fig. 10. Precipitating clouds
D. M. Vavriv, V. A. Volkov, V. N. Bormotov, V. V. Vynogradov, R. V. Kozhyn, B. V. Trush, A. A. Belikov, and V. Ye. Semenyuta
132 Ðàäèîôèçèêà è ðàäèîàñòðîíîìèÿ, 2002, ò.7, ¹2
summer the activity reaches its maximum. Vari-
ous hypotheses have been put forward in order to
explain the nature of the discussed reflections.
Air turbulence, air layers, aerosols, insects, and
birds have been considered as possible scatter-
ers. However, any of these hypotheses can ex-
plain simultaneously all principal features of the
boundary layer reflections.
4. 95 GHz Cloud Radar
The first version of the 95 GHz Doppler cloud
radar was completed and tested in our Institute
in 1999. In 2001, this radar was upgraded to per-
form polarimetric measurements. A photo of the
radar system is given in Fig. 11. The measured
parameters and technical characteristics of the
radar are given in Tables 1 and 2, respectively.
A simplified block diagram of the radio frequen-
cy part of the radar is shown in Fig. 12.
The separate 0.5-meter parabolic antennas are
used for the transmitter and receiver ends. A
polarization independent illuminator is used in
the both antennas. In order to realize polarimet-
ric measurements, ferrite quasioptical polariza-
tion manipulators are introduced between the re-
ceiver and its antenna, as well as between the
transmitter and corresponding antenna. The ma-
nipulators are computer controlled allowing to
obtain the pulse-to-pulse variation of the polar-
ization of transmitted pulses and measurement
of co- and cross-polarized components of the
backscattered signals.
The transmitter is based on a 4 kW spatial-
harmonic magnetron with cold secondary-emission
cathode and a hard-tube modulator. The pulse du-
ration is software controlled between 0.05 µs and
0.4 µs, and the maximum pulse repetition frequen-
cy is 5 kHz.
The radar receiver was built by using a scheme
with the double frequency conversion. The first
local oscillator is realized on a chain which con-
sists of a highly stable, tunable oscillator operat-
ing at a frequency of about 10 GHz, a frequency
multiplier, and a 95 GHz amplifier. The second
local oscillator is a voltage-controlled generator
with a maximum frequency deviation of 50 MHz.
It is included in the loop for automatic frequency
control.
The signal channel after the second mixer in-
cludes the stages of time-varying and manual gain
control which provide the total dynamic range of
90 dB. Following these stages, the received sig-
nals are fed to a quadrature demodulator together
with the output of a coherent oscillator (COHO).
The outputs of the demodulator are used for phase
and amplitude measurements in the data acquisi-
tion system.
5. Side-Looking Airborne Radar
5.1. Radar Characteristics
The radar system consists of the 95 and
36 GHz channels with the corresponding anten-
nas, transmitters, receivers, and signal pre-process-
ing units as shown in Fig 13. A single interface
unit and a host computer are used for both chan-
nels. The radar system also contains a navigation
and orientation system (NOS), which include the
GPS receiver, the autonomous gyroscope angle sen-
sors, and an altimeter. The NOS is introduced in
order to account for the variations of aircraft alti-
tude, pitch angle, roll, and bank, necessary to pro-
duce a high quality radar image of the sea surface.
The general characteristics of the radar system are
given in Table 3.
A single antenna is used in the 8 mm wave
channel for both the transmitter and receiver. The
Fig. 11. A photo of the 95 GHz radar system
Millimeter-Wave Radars for Environmental Studies
133Ðàäèîôèçèêà è ðàäèîàñòðîíîìèÿ, 2002, ò. 7, ¹2
Fig. 12. A simplified block diagram of the radio frequency part of the 95 GHz radar
D. M. Vavriv, V. A. Volkov, V. N. Bormotov, V. V. Vynogradov, R. V. Kozhyn, B. V. Trush, A. A. Belikov, and V. Ye. Semenyuta
134 Ðàäèîôèçèêà è ðàäèîàñòðîíîìèÿ, 2002, ò.7, ¹2
receiver and transmitter are decoupled by means
of a circulator and a pin-modulator. An original
�dielectric waveguide � diffraction grating� an-
tenna with V-V polarisation is used [25]. It has a
planar construction with the dimensions of
100 30 5× × cm3. The antenna forms a beavertail
radiation pattern of 0.5 40 ,°× ° with the gain of
37 dB, and a side lobe level of � 20 dB.
The problem of the transmitter-receiver de-
coupling in the 3 mm-wave channel is solved by
the application of two separate identical anten-
nas for the receiver and the transmitter ends. The
antennas are of horn-parabolic type, where a par-
abolic cylinder is used as the reflection surface.
Metal sheets overlap the end surfaces of the cyl-
inder in order to reduce the side-lobes which are
�18 dB down. A plane sub-reflector is introduced
in order to decrease the antenna dimensions. The
radiation pattern of these antennas is similar to
that of the 8 mm-wave antenna.
The receivers for both radar channels have been
built by using a scheme with the double frequency
conversion and with a frequency control loop.
Special efforts have been made to obtain a large
Fig. 13. Block diagram of the dual frequency radar system
Millimeter-Wave Radars for Environmental Studies
135Ðàäèîôèçèêà è ðàäèîàñòðîíîìèÿ, 2002, ò. 7, ¹2
dynamic range of the receiver, low level of the
phase noise, and to simultaneously satisfy linear-
ity of the control characteristics.
During the first experiments, the radar system
was installed on a helicopter MI-8. Due to small
dimensions of the radar, it was possible to place
the radar just in an open door of the helicopter, as
is shown in Fig. 14.
5.2. Oil-Spill Detection
The detection of oil spills by means of the
side-looking radars or SAR systems usually lies
in the analysis of reflectivity charts [12, 13, 26].
The presence of an oil film on the water surface
leads to smoothing the surface, causing a reduc-
tion of the backscattering reflectivity coefficient
which is readily detected by corresponding anal-
ysis of the radar returns. So far, the capabilities
to detect oil spills with side-looking radars or SAR
systems have mainly been demonstrated in the
experiments undertaken over the sea or ocean
surfaces. The first measurement campaign with
the above described radar system dealt with the
investigation of oil films on the river and lake
surfaces. This campaign was organized in Sep-
tember 1997 near Nizshniy Novgorod, Russia, in
cooperation with the Institute of Radio Physics
and Electronics of the Ukrainian Academy of
Sciences and the Research and Development In-
stitute of Radio Technical Measurements.
Two main peculiarities of the oil-spill de-
tection on the river and lake surfaces should be
Fig. 14. The dual frequency radar system installed on
a helicopter
Table 3. General characteristics of the dual frequency radar system
Transmitted frequencies, GHz 36.8±0.5 95±0.5
Peak transmit power, kW 20 4
Pulse length, µs 0.05 � 0.4 0.05 � 0.4
Pulse repetition frequency, kHz 5 5
Receiver noise figure, dB 4.5 8
Dynamic range, dB 60 60
Tilt angles, degree from 30 to 70 from 30 to 70
Beam width in azimuthal plane, degree 0.5 0.5
Polarization Vertical Vertical
Resolution in the flight perpendicular direction Better than 30 m Better than 30 m
Resolution in azimuthal direction
(from the flight altitude of 4 km) Better than 60 m Better than 60 m
Width of the instantaneous observation area
(from the flight altitude of 4 km), km 8.5 8.5
DC supply voltage, V 28
Watt consumption (max) 1500
Total weight, kg 70
D. M. Vavriv, V. A. Volkov, V. N. Bormotov, V. V. Vynogradov, R. V. Kozhyn, B. V. Trush, A. A. Belikov, and V. Ye. Semenyuta
136 Ðàäèîôèçèêà è ðàäèîàñòðîíîìèÿ, 2002, ò.7, ¹2
mentioned. Firstly, the signal of a relatively
small intensity reflected from the water sur-
face is usually present in the receiver output
together with the rather intense signals reflect-
ed from the river or lake banks. Therefore the
receivers with a large dynamical range and a
rather fast time varying gain control are neces-
sary. The transient processes in the receivers
should also be minimized to a great extent.
Secondly, the radar contrast of oil spills on such
surfaces is typically small compared with that
on the sea or ocean surfaces because of the
relatively small amplitudes of the surface waves
on slick-free surfaces. Nevertheless, the exper-
iments have shown that the radar system de-
veloped has a large potential for oil-spill de-
tection even in case of rather small wind. For
example, the radar contrast of an oil slick shown
in Fig. 15 and 16 is about 6 dB. This slick was
detected when the maximum amplitude of the
surface waves on the slick-free surface was only
1 cm. The thickness of the oil film was about
0.05 mm.
Another series of experiments have been or-
ganized dealing with the detection of oil spills in
a spool of 20 10× m, which is shown in Fig. 17.
An oil film has covered the half of the pool.
This part of the spool on the radar image is
markedly different from the slick-free part of
the pool, as is shown in Fig. 18. There was prac-
tically no wind during the measurements, and
the amplitude of the surface waves was smaller
Fig. 16. Radar image of the oil slick shown in Fig. 18
Fig. 17. Experimental pool, which is covered by half
by oil film
Fig. 18. Radar image of the pool. The oil spill is shown
by blue
Fig. 15. Optical image of an oil slick on a river
Millimeter-Wave Radars for Environmental Studies
137Ðàäèîôèçèêà è ðàäèîàñòðîíîìèÿ, 2002, ò. 7, ¹2
than 1 cm. It should be noted that the oil spill is
detected even when the dimensions of the pool
are relatively small as compared to the spatial
resolution of the radar system.
Thus, the experiments have demonstrated a
high capability of the developed radar system
for the detection of oil spills on the river and
lake surfaces. The results also indicate that the
radar system can be effectively used for reveal-
ing and investigation of leakage from oil pipe-
lines by means of detection of oil films on near-
by rivers and lakes.
6. Conclusion
The development of radar systems for environ-
mental studies has been initiated during the last years
in the Institute of Radio Astronomy to meet the
current demand for a new generation of such sys-
tems. The 95 and 36 GHz cloud radar systems and
the dual-frequency 95 and 36 GHz side-looking
airborne radar system have been developed, pro-
duced, and tested. These systems have embodied
recent advances in the development of high power
compact magnetron transmitters, mm-wave receiv-
ers, novel types of antennas, high speed digital sig-
nal processing boards, and signal processing tech-
nique. The obtained measurement results have dem-
onstrated a high potential of the developed systems
for various remote sensing applications.
Acknowledgements
The authors would like to thank all of their col-
leagues at the Department of Microwave Electron-
ics of the Institute of Radio Astronomy for their
effort in the development of the cloud radars. The
helpful cooperation with Dr. V. I. Kazantsev, Prof.
B. A. Rozanov, Dr. A. C. Kurekin, and A. S. Gavri-
lenko is appreciated. The authors are indebted to
Prof. L. Lytvynenko, Prof. K. Schünemann, and
Dr. G. Peters for fruitful discussions and support.
References
1. F. Pasqualucci, B. W. Bartram, R. A. Kropfli, and
W. R. Moninger. J. Climate Appl. Meteor. 1983, 22,
pp. 758-765.
2. T. Takeda and M. Horiguchi. J. Atmos. Oceanic
Technol. 1986, 64, pp. 109-122.
3. R. M. Lhermitte. J. Atmos. Oceanic Technol. 1987,
4, pp. 36-48.
4. J. B. Mead, A. L. Pazmany, S. M. Sekelsky,
R. E. McIntosh. Proc. IEEE. 1994, 82, pp. 1891-1906.
5. R. A. Kropfly and R. D. Kelly. Meteor. Atmos. Phys.
1996, 59, pp. 105-121.
6. O. Danne, M. Quante, E. Raschke, and C. Weitkamp.
Phys. Chem. Earth (B). 1999, 24, pp. 167-171.
7. K. P. Moran, B. E. Martner, M. J. Post,
R. A. Kropfli, D. C. Welsh, and K. B. Widener. Bull.
Amer. Meteor. Soc. 1998, 79, pp. 443-455.
8. V. Bormotov, G. Peters, K. Schünemann, D. Vavriv,
V. Vinogradov, and V. Volkov. Proc. of the Millennium
Conf. on Antennas and Propagation. Davos,
Switzerland, 2000, p. 319.
9. V. Bormotov, G. Peters, K. Schünemann, D. Vavriv,
V. Vinogradov, and V. Volkov. MST9 � COST 76
Workshop. France, Toulouse. 2000.
10. D. M. Vavriv. �Physics and Engineering of
Millimeter and Sub-Millimeter Waves�. Kharkov,
Ukraine, 2001, pp. 85-89.
11. M. Jenett , V. Kazantsev, A. Kurekin,
K. Schünemann, D. Vavriv, V. Vinogradov, and
V. Volkov. Int. Geoscience and Remote Sensing
Symposium. Hamburg. 1999.
12. N. Bartsch, K. Gruner, W. Keydel, and F. Witte.
IEEE Trans. Geosci. Remote Sensing. 1987, GE-25,
pp. 677-690.
13. E. N. Belov, et al. Proc. of 7-th Int. Crimean
Microwave Conf. Sept. 1997, Sevastopol, Ukraine,
pp. 56-61.
14. K. Schünemann, A. Timchenko, and A. Serebryannikov.
�A new model of electromagnetic wave scattering from
sea surface with and without oil films� (in press).
15. I. M. Vigdorchik, V. D. Naumenko, V. P. Timofeev.
Doklady Ukr. Akademii Nauk. 1975, A, No. 7,
pp. 634-637 (in Russian).
16. V. D. Naumenko, K. Schünemann, and D. M. Vavriv.
Electronics Letters. 1999, 35, pp. 1960-1961.
17. K. Schünemann, S. Sosnitskiy, and D. M. Vavriv.
IEEE Trans. on ED. 2001, 48, pp. 993-998.
18. V. D. Naumenko, K. Schünemann, V. Ye. Semenuta,
D. M. Vavriv, and V. A. Volkov. Proc. of the 22-nd
Int. Conf. on Infrared and Millimeter Waves. USA,
1997, pp. 42-43.
19. K. Schünemann, B. Trush, D. Vavriv, and V. Volkov.
Proc. of the 30-th European Micr. Conf. Paris, 2000.
20. M. Jenett, R. Kozshin, K. Schünemann, D Vavriv,
and V. Vinogradov. Proc. of the Int. Geoscience and
Remote Sensing Symposium. Hamburg, 1999.
D. M. Vavriv, V. A. Volkov, V. N. Bormotov, V. V. Vynogradov, R. V. Kozhyn, B. V. Trush, A. A. Belikov, and V. Ye. Semenyuta
138 Ðàäèîôèçèêà è ðàäèîàñòðîíîìèÿ, 2002, ò.7, ¹2
21. D. M. Vavriv, V. V. Vinogradov, and S. A. Razbejko.
Radio Physics and Radio Astronomy. 2001, 6, No. 3,
pp. 212-221.
22. D. Atlas. Advances in Radar Meteorology.
Academic Press. 1964.
23. H. Ottersten. Radio Science. 1969, 4, No. 12,
pp. 1251-1255.
24. R. M. Lhermitte. Journal of the Atmospheric
Sciences. 1966, 23, pp. 575-591.
25. A. P. Yevdokimov, and V. V. Krizhanovsky.
Radioelectronics. 1996, 39, pp. 54-61.
26. J. T. Macklin. GEC J. of Research. 1992, 10,
pp. 19-27.
Ðàäèîëîêàòîðû ìèëëèìåòðîâîãî
äèàïàçîíà äëèí âîëí äëÿ èññëåäîâàíèÿ
ïàðàìåòðîâ îêðóæàþùåé ñðåäû
Ä. Ì. Âàâðèâ, Â. À. Âîëêîâ,
Â. Í. Áîðìîòîâ, Â. Â. Âèíîãðàäîâ,
Ð. Â. Êîæèí, Á. Â. Òðóø, À. À. Áåëèêîâ,
Â. Å. Ñåìåíþòà
 ñòàòüå îáîáùåíû ðåçóëüòàòû ðàáîò, èíè-
öèèðîâàííûõ â ïîñëåäíåå âðåìÿ â Ðàäèîàñò-
ðîíîìè÷åñêîì èíñòèòóòå ÍÀÍ Óêðàèíû, ïî
ñîçäàíèþ ðàäèîëîêàòîðîâ ìèëëèìåòðîâîãî
äèàïàçîíà äëèí âîëí. Ðàçðàáîòàííûå ðàäèî-
ëîêàöèîííûå ñèñòåìû âêëþ÷àþò ìåòåîðîëî-
ãè÷åñêèå ëîêàòîðû è ñàìîëåòíûé ðàäèîëîêà-
òîð áîêîâîãî îáçîðà. Îíè äàþò âîçìîæíîñòü
ïðîâåäåíèÿ èçìåðåíèé â 8- è 3-ìì äèàïàçîíàõ
äëèí âîëí ñ âûñîêèì ïðîñòðàíñòâåííûì ðàç-
ðåøåíèåì â ðåàëüíîì âðåìåíè. Â ñòàòüå îá-
ñóæäàþòñÿ âîïðîñû ïîñòðîåíèÿ ýòèõ èíñòðó-
ìåíòîâ, èñïîëüçîâàííûå íîâûå òåõíè÷åñêèå
ðåøåíèÿ è ìåòîäû îáðàáîòêè ñèãíàëîâ. Ïðåä-
ñòàâëåíû òàêæå ðåçóëüòàòû ïðîâåäåííûõ èç-
ìåðåíèé.
Ðàä³îëîêàòîðè ì³ë³ìåòðîâîãî ä³àïàçîíó
äîâæèí õâèëü äëÿ äîñë³äæåííÿ
ïàðàìåòð³â íàâêîëèøíüîãî
ñåðåäîâèùà
Ä. Ì. Âàâð³â, Â. À. Âîëêîâ,
Â. Ì. Áîðìîòîâ, Â. Â. Âèíîãðàäîâ,
Ð. Â. Êîæèí, Á. Â. Òðóø, Î. Î. Áºë³êîâ,
Â. ª. Ñåìåíþòà
Ó ñòàòò³ óçàãàëüíåí³ ðåçóëüòàòè ðîá³ò,
³í³ö³éîâàíèõ îñòàíí³ì ÷àñîì ó Ðàä³îàñòðîíî-
ì³÷íîìó ³íñòèòóò³ ÍÀÍ Óêðà¿íè, ïî ñòâîðåí-
íþ ðàä³îëîêàòîð³â ì³ë³ìåòðîâîãî ä³àïàçîíó
äîâæèí õâèëü. Ðîçðîáëåí³ ðàä³îëîêàö³éí³ ñè-
ñòåìè âêëþ÷àþòü ìåòåîðîëîã³÷í³ ëîêàòîðè ³
ë³òàêîâèé ðàä³îëîêàòîð á³÷íîãî îãëÿäó. Âîíè
äàþòü ìîæëèâ³ñòü ïðîâåäåííÿ âèì³ðþâàíü ó
8- ³ 3-ìì ä³àïàçîíàõ äîâæèí õâèëü ç âèñîêèì
ïðîñòîðîâèì ðîçä³ëåííÿì ó ðåàëüíîìó ÷àñ³.
Ó ñòàòò³ îáãîâîðþþòüñÿ ïèòàííÿ ïîáóäîâè öèõ
³íñòðóìåíò³â, âèêîðèñòàí³ íîâ³ òåõí³÷í³ ð³øåí-
íÿ ³ ìåòîäè îáðîáêè ñèãíàë³â. Ïðåäñòàâëåíî
òàêîæ ðåçóëüòàòè ïðîâåäåíèõ âèì³ðþâàíü.
|