Аspects of electromagnetic compatibility at remote sensing of ionosphere in radiophysical observatory of Кharkiv National University
Specific responses of radio receivers of various type and frequency range under conditions to receiving of both a sole intense ultrashort signals and combination of information and interference ultrashort signals are studied. A possible scenario of functional upset of radio receivers at the V.N. Ka...
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Національний науковий центр «Харківський фізико-технічний інститут» НАН України
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Magda, I.I. Chernogor, L.F. 2019-02-14T14:23:57Z 2019-02-14T14:23:57Z 2018 Аspects of electromagnetic compatibility at remote sensing of ionosphere in radiophysical observatory of Кharkiv National University / I.I. Magda, L.F. Chernogor // Вопросы атомной науки и техники. — 2018. — № 4. — С. 122-126. — Бібліогр.: 18 назв. — англ. 1562-6016 PACS: 84.40, 94.05, 94.406 https://nasplib.isofts.kiev.ua/handle/123456789/147347 Specific responses of radio receivers of various type and frequency range under conditions to receiving of both a sole intense ultrashort signals and combination of information and interference ultrashort signals are studied. A possible scenario of functional upset of radio receivers at the V.N. Karazin Kharkiv National University Radiophysical Observatory during remotely sensing the ionosphere with new radar transmitting a few hundred MW ~10 ns pulse has been analyzed. In the tests of receivers, the characteristics of interference signals well enough meet the conditions of planned experiments to probe the ionosphere. It is expected that the research results will contribute to the development of various preventive measures for the electromagnetic protection of the radio facilities at the Radiophysical Observatory. Досліджуються характерні види реакції радіоприймальних пристроїв різних типів і частотного діапазону в умовах прийому інтенсивних сигналів надкороткої тривалості, а також в умовах комбінованого прийому інформаційних сигналів і перешкоджаючих сигналів надкороткої тривалості. Проведено аналіз можливого сценарію збоїв радіоприймальних пристроїв радіофізичної обсерваторії ХНУ в умовах сеансу дистанційного радіозондування іоносфери, в якому використовується нове обладнання з імпульсною потужністю до декількох сотень мегават і тривалістю імпульсу близько 10 нс. У тестах приймальних пристроїв використані характеристики перешкоджаючих сигналів, які досить повно відображають можливі умови передбачуваних експериментів з радіозондування іоносфери. Передбачається, що результати досліджень будуть сприяти розробці різних превентивних заходів щодо електромагнітного захисту радіоелектронної апаратури обсерваторії. Исследуются характерные виды реакций радиоприемных устройств различных типов и частотного диапазона в условиях приема интенсивных сигналов сверхкороткой длительности, а также в условиях комбинированного приема информационных сигналов и помеховых сигналов сверхкороткой длительности. Проведен анализ возможного сценария сбоев радиоприемных устройств радиофизической обсерватории ХНУ в условиях сеанса дистанционного радиозондирования ионосферы, в котором используется новое оборудование с импульсной мощностью до нескольких сотен мегаватт и длительностью импульса около 10 нс. В тестах приемных устройств использованы характеристики помеховых сигналов, которые достаточно полно отражают возможные условия предполагаемых экспериментов по радиозондированию ионосферы. Предполагается, что результаты исследований будут способствовать разработке различных превентивных мероприятий по электромагнитной защите радиоэлектронной аппаратуры обсерватории. en Національний науковий центр «Харківський фізико-технічний інститут» НАН України Вопросы атомной науки и техники Коллективные процессы в космической плазме Аspects of electromagnetic compatibility at remote sensing of ionosphere in radiophysical observatory of Кharkiv National University Аспекти електромагнітної сумісності при дистанційному зондуванні іоносфери в радіофізичній обсерваторії Харківського національного університету Аспекты электромагнитной совместимости при ионосферном дистанционном зондировании в радиофизической обсерватории Харьковского национального университета Article published earlier |
| institution |
Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| collection |
DSpace DC |
| title |
Аspects of electromagnetic compatibility at remote sensing of ionosphere in radiophysical observatory of Кharkiv National University |
| spellingShingle |
Аspects of electromagnetic compatibility at remote sensing of ionosphere in radiophysical observatory of Кharkiv National University Magda, I.I. Chernogor, L.F. Коллективные процессы в космической плазме |
| title_short |
Аspects of electromagnetic compatibility at remote sensing of ionosphere in radiophysical observatory of Кharkiv National University |
| title_full |
Аspects of electromagnetic compatibility at remote sensing of ionosphere in radiophysical observatory of Кharkiv National University |
| title_fullStr |
Аspects of electromagnetic compatibility at remote sensing of ionosphere in radiophysical observatory of Кharkiv National University |
| title_full_unstemmed |
Аspects of electromagnetic compatibility at remote sensing of ionosphere in radiophysical observatory of Кharkiv National University |
| title_sort |
аspects of electromagnetic compatibility at remote sensing of ionosphere in radiophysical observatory of кharkiv national university |
| author |
Magda, I.I. Chernogor, L.F. |
| author_facet |
Magda, I.I. Chernogor, L.F. |
| topic |
Коллективные процессы в космической плазме |
| topic_facet |
Коллективные процессы в космической плазме |
| publishDate |
2018 |
| language |
English |
| container_title |
Вопросы атомной науки и техники |
| publisher |
Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
| format |
Article |
| title_alt |
Аспекти електромагнітної сумісності при дистанційному зондуванні іоносфери в радіофізичній обсерваторії Харківського національного університету Аспекты электромагнитной совместимости при ионосферном дистанционном зондировании в радиофизической обсерватории Харьковского национального университета |
| description |
Specific responses of radio receivers of various type and frequency range under conditions to receiving of both a
sole intense ultrashort signals and combination of information and interference ultrashort signals are studied. A possible scenario of functional upset of radio receivers at the V.N. Karazin Kharkiv National University Radiophysical
Observatory during remotely sensing the ionosphere with new radar transmitting a few hundred MW ~10 ns pulse
has been analyzed. In the tests of receivers, the characteristics of interference signals well enough meet the conditions of planned experiments to probe the ionosphere. It is expected that the research results will contribute to the
development of various preventive measures for the electromagnetic protection of the radio facilities at the Radiophysical Observatory.
Досліджуються характерні види реакції радіоприймальних пристроїв різних типів і частотного діапазону в умовах прийому інтенсивних сигналів надкороткої тривалості, а також в умовах комбінованого прийому інформаційних сигналів і
перешкоджаючих сигналів надкороткої тривалості. Проведено аналіз можливого сценарію збоїв радіоприймальних пристроїв радіофізичної обсерваторії ХНУ в умовах сеансу дистанційного радіозондування іоносфери, в якому використовується нове обладнання з імпульсною потужністю до декількох сотень мегават і тривалістю імпульсу близько 10 нс. У тестах
приймальних пристроїв використані характеристики перешкоджаючих сигналів, які досить повно відображають можливі
умови передбачуваних експериментів з радіозондування іоносфери. Передбачається, що результати досліджень будуть
сприяти розробці різних превентивних заходів щодо електромагнітного захисту радіоелектронної апаратури обсерваторії.
Исследуются характерные виды реакций радиоприемных устройств различных типов и частотного диапазона в условиях
приема интенсивных сигналов сверхкороткой длительности, а также в условиях комбинированного приема информационных
сигналов и помеховых сигналов сверхкороткой длительности. Проведен анализ возможного сценария сбоев радиоприемных
устройств радиофизической обсерватории ХНУ в условиях сеанса дистанционного радиозондирования ионосферы, в
котором используется новое оборудование с импульсной мощностью до нескольких сотен мегаватт и длительностью
импульса около 10 нс. В тестах приемных устройств использованы характеристики помеховых сигналов, которые достаточно
полно отражают возможные условия предполагаемых экспериментов по радиозондированию ионосферы. Предполагается,
что результаты исследований будут способствовать разработке различных превентивных мероприятий по электромагнитной защите радиоэлектронной аппаратуры обсерватории.
|
| issn |
1562-6016 |
| url |
https://nasplib.isofts.kiev.ua/handle/123456789/147347 |
| citation_txt |
Аspects of electromagnetic compatibility at remote sensing of ionosphere in radiophysical observatory of Кharkiv National University / I.I. Magda, L.F. Chernogor // Вопросы атомной науки и техники. — 2018. — № 4. — С. 122-126. — Бібліогр.: 18 назв. — англ. |
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2025-11-25T23:55:25Z |
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2025-11-25T23:55:25Z |
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| fulltext |
ISSN 1562-6016. ВАНТ. 2018. №4(116) 122
ASPECTS OF ELECTROMAGNETIC COMPATIBILITY
AT REMOTE SENSING OF IONOSPHERE IN RADIOPHYSICAL
OBSERVATORY OF KHARKIV NATIONAL UNIVERSITY
I.I. Magda1, L.F. Chernogor2
1National Science Center “Kharkov Institute of Physics and Technology”, Kharkov, Ukraine;
E-mail: magda@kipt.kharkov.ua;
2V.N. Karazin Kharkiv National University, Kharkov, Ukraine
E-mail: leonid.f.chernogor@univer.kharkov.ua
Specific responses of radio receivers of various type and frequency range under conditions to receiving of both a
sole intense ultrashort signals and combination of information and interference ultrashort signals are studied. A pos-
sible scenario of functional upset of radio receivers at the V.N. Karazin Kharkiv National University Radiophysical
Observatory during remotely sensing the ionosphere with new radar transmitting a few hundred MW ~10 ns pulse
has been analyzed. In the tests of receivers, the characteristics of interference signals well enough meet the condi-
tions of planned experiments to probe the ionosphere. It is expected that the research results will contribute to the
development of various preventive measures for the electromagnetic protection of the radio facilities at the Radio-
physical Observatory.
PACS: 84.40, 94.05, 94.406
INTRODUCTION
For successful implementation of the scientific pro-
ject "Ionosat-Micro" [1], set by the National Target-
Oriented Scientific and Technical Space Program of
Ukraine for 2013-2017, the ground-based sub-satellite
monitoring of the geospace environment with the re-
mote sensing facilities located at the V.N. Karazin
Kharkiv National University (KhNU) Radiophysical
Observatory (RPO) has been planned [2], which re-
quired a metrological verification and certification of
the instruments. This work was accompanied by a de-
tailed investigating an impact of different radio elec-
tronic systems (RES) on radio receivers. On-site meas-
urements were preceded by vast laboratory studying the
electromagnetic fields impact on radio receivers (RR)
and their components. The work was carried on within
the framework of well-known and described in scientific
literature methods of electromagnetic compatibility and
strength (EMCS) against the impact of stationary or rela-
tively long-pulse interference (see, for example, [3 - 5]).
The present work aims at analyzing a possible sce-
nario of the RRs functional upset during a new cycle of
remote radio sensing of the ionosphere at the KhNU
RFO. A modernized multi-purpose UHF sensing system
based on the UHF radar has been proposed to be used in
these experiments. This up-grade supposes providing a
pulse compression in the master oscillator in order to
increase its pulse power to several hundred megawatts.
In this case, the pulse width should be reduced from
1 μs to 10 ns. In this concern, the investigation of the
RRs response to the impact of ultrashort pulse (USP)
~0.1…10 ns [6 - 8] interference, which previously had
not been carried out due to the lack of technical means,
becomes relevant.
It is known that under the impact of interference sig-
nals (IS), depending on their amplitude, a wide spec-
trum of phenomena (from functional upset to total fail-
ure) arises in the RR operation caused by changes in the
characteristics of the components. At the same time, if
the interference is the USP signal with the pulse width
τp and pulse rise time τr of 10-9…10 8 s and 10-10…10-11 s,
respectively, the character of the arising effects is sig-
nificantly different in comparison with the steady-state
or long-pulse impact [9 - 12].
The specific responses of the receivers of different
type and in different frequency ranges irradiated by the
USP IS either solely or in combination with the RF in-
formation signal (IFS) are presented below. The selec-
tion of types of the receivers, as well as of the test sig-
nals characteristics quite fully reflects the conditions
that can arise in the planned experiments on radio prob-
ing the ionosphere. The test results can be useful for
providing the preventive technical and organizational
measures for electromagnetic protection of the RES,
which operate in the KhNU Radiophysical Observatory.
1. BRIEF INFORMATION OF THE KHNU
RADIOPHYSICAL OBSERVATORY
From the beginning of the 1950s to the present time,
the geospace researches have been carried out at KhNU
(see, for example, [13 - 15]). Since the 1960s, the Radi-
ophysical Observatory equipped with automated and
computerized systems for remote sensing the geospace
environment in a wide range of altitudes
(z ≈ 60...1000 km) had been put into operation. A com-
plex investigation along with modeling, and predicting
the fundamental geospace physical and chemical pro-
cesses of natural and anthropogenic origin (which can
affect on functional stability of the telecommunication,
power and machinery systems as well as on human
health and wellbeing, etc.) have been run in the frame-
work of ground support for the scientific project "Iono-
sat-Micro" [1]. The facilities for remote radio-sensing
the ionosphere has been continuously improved and
upgraded. The Facility for Remote Sensing the Near-
Earth Space Environment at the Kharkiv V. N. Karazin
National University Radiophysical Observatory is in-
cluded in the State Register of Scientific Research In-
struments that Constitute a National Asset. Table 1 pre-
sents a brief description of the receiving devices includ-
ed into basic tools of the remote radio-sensing of the
ionosphere [2] in RPO.
mailto:magda@kipt.kharkov.ua
mailto:leonid.f.chernogor@univer.kharkov.ua
ISSN 1562-6016. ВАНТ. 2018. №4(116) 123
Table 1
Characteristics of the receivers in the radio systems
at the RPO
System Radio frequency
band (bandwidth) Critical level, Uin
MF radar 1.5…24 MHz
(40 kHz)
0.02…0.2
HF Doppler
radar at vertical
incidence
1…24 MHz
(10 Hz)
0.02…0.05
Digisonde 1…15 MHz
(1…16 kHz)
0.05…0.1
Multi-
frequency pas-
sive radar
3…30 MHz
(300 Hz),
30…300 MHz,
300…3000 MHz,
3…30 GHz
(10 kHz)
0.02…0.05
Fluxgate magne-
tometer
(based on IM-II
magnetometer)
0.001…1 Hz 10…100 nТ
GPS/GLONASS
receivers
150/400 MHz
1.2…1.6 GHz
0.01…0.03
0.003…0.03
* special fabrication
2. RF POWER AT THE INPUT
OF THE RECEIVER DISPOSED CLOSE
TO HIGH-POWER RADIATOR
The supposed interference signal levels produced by
radar with the RF power output of 100 MW have be
estimated for various distances and decrease factors as a
function of the antenna directivity. It is well known, the
RF power at the input of the receiving antenna is
( )
2
24
T R
in T
G GP P
R
λ
=
π
,
where PT is the transmitter power, GT and GR are the
transmitting and receiving antenna gains, respectively, λ is
the wave-length, R is the distance between the antennas.
Table 2
Power Pin (top line, W) and voltage Uin (bottom line, V)
at receiver input (Rin=75 Ω) versus the distance to and
side-lobe levels of transmitting antenna
GT dB R, m
15 45 150 450 1500
0 3.2⋅106
2.2⋅104
3.2⋅105
6.9⋅103
3.2⋅104
2.2⋅103
3.2⋅103
690
320
220
–10 3.2⋅105
6.9⋅103
3.2⋅104
2.2⋅103
3.2⋅103
690
3.2⋅102
220
32
69
–20 3.2⋅104
2.2⋅103
3.2⋅103
690
3.2⋅102
220
3.2⋅101
69
3.2
22
–30 3.2⋅103
690
3.2⋅102
220
3.2⋅101
69
3.2
22
0.32
6.9
–40 3.2⋅102
220
3.2⋅101
69
3.2
22
0.32
6.9
3.2⋅10–2
2.2
–50 3.2⋅101
69
3.2
22
0.32
6.9
3.2⋅10–2
2.2
3.2⋅10–3
0.69
The amplitudes of the power Pin (and voltage Uin) at
the receiver input with the input resistance Rin calculated
for PT = 0.1 GW, GT = 5.104, GR = 1, Rin = 75 Ω, and λ
= 0.15 m are given in Table 2. Apparently, such high
impulse amplitudes at the RR input are sufficiently
higher than those indicated in Table 1, and can result in
functional upsets and even destruction. To better under-
stand possible effects in receiving devices of the Obser-
vatory, the results of laboratory tests of various types of
receivers on functional upset under the exposure to the
USP IS are described below.
Table 3
Test conditions of receivers of different frequency bands
Test signals mode
Receiver
frequency
band
Test signals
characteristics
τp/τr, ns Uin , V
I,а
I,b
UWB VP or
transient pro-
cess
HF, UHF,
VHF,
SHF
1…500/
0.3…20
1…5/0.2…1
10–6…10
10–4…100
II NB RF in
frequency
band of RR
SHF 6…15/3 10–4…20
III Combination
NB RF and
UWB VP with
5 ns delay time
between signals
HF/UHF,
VHF,
SHF
NB RF
15/3
UWB VP
1.2/0.2
10–3…10
10–3…10
3. EXPERIMENTAL STUDY
OF FUNCTIONAL UPSETS IN RECEIVERS
AFFECTED BY USP IS
From the above, it follows that the efficiency of the
USP interference should depend substantially on the
time (frequency) characteristics of IS and the receiving
circuit. This has been studied in the tests of RRs, which
had significantly different frequency bandwidth of the
input components [16 - 18]. For this purpose, conven-
tional HF, UHF, and VHF receivers, as well as mock-
ups of SHF receivers have been used (Fig. 1).
Fig. 1. Diagram of RR test: 1 – G4-116 signal genera-
tor; 2 – G5-78 impulse generator; 3 – impulse genera-
tor G5-54; 4-5 – 30 dB attenuator; 5 – RR under test;
6 – S1-70 sampling oscilloscope; 7 – personal computer
In the first case, the RRs had a narrow input fre-
quency band due to the presence of a resonant tunable
input RF circuit. In the second case, the input filters
were removed in a RR, and the bandwidth of the receiv-
ing circuit was determined mainly by the properties of
the low-noise amplifier (LNA), which usually has
slightly varying characteristics over a wide (up to sever-
al octaves) frequency range.
The test conditions of the receivers differed in the
signal composition – the combinations of RF harmonics
and USP signals, as well as in the USP IS mode (Ta-
ble 3). The modulated narrowband harmonics signals
(NB RF) played the role of the IFS. The ultra-wideband
video pulse (UWB VP) signals simulated the USP IS.
The difference in the UWB VP signals was determined
mainly by the pulse and rise-time durations. Thus, the
following signals were applied to the input of the radio
receiver units: (1) NB RF with Δf << f0; (2) UWB VP
with Δf ~ f0; (3) combined NB RF and UWB VP.
ISSN 1562-6016. ВАНТ. 2018. №4(116) 124
3.1. RF RECEIVER RESPONSE
In view of the fact that different NB receivers in HF,
UHF, and VHF bands have identical responses to the IS,
the test of a conventional 3rd-class R-323M receiver is
considered below as an example. The RR test was car-
ried out using a close-type test-bed in conditions of di-
rect injection of USP IS and IFS to the RR input, Fig. 1.
The specific characteristics of the RR output signals
were determined, which corresponded to the nonlinear
response of the device (see Table 3, mode I,a): (1) the
RR nonlinear response width τres at the output of the
units: RFA, IFA, and LF; (2) the minimum width of the
USP IS τp min, when the impact on RR can be interpreted
as a shock-like, producing a specific nonlinear response;
(3) the critical repetition frequency of the USP IS, Fr cr,
when the individual responses at the RR output are
overlapped and perceived as a continuous signal (recep-
tion blocking).
а 50 ns/div
b 0.05 ms/div
c 1 ms/div
Fig. 2. Typical responses of the output units of HF/UHF
band RRs: (а) HFA, (b) IFA, (с) LFA in the modes of
single IS (а and b), and combination of IS and IFS (с).
IFS (f0 = 22 MHz, AM, FАM = 1 kHz),
USP IS (τp = 5 ns, τr= 0.45 ns, Fr = 1 kHz)
Fig. 2 demonstrates the response at the receiver HF,
UHF, and VHF units (a − HFA, b − IFA, and c − LFA)
obtained in the mode of single IS, Fig. 2,a,b), and of
combination of IS and IFS, Fig. 2,b. The IFC was a con-
tinuous harmonic signal with the carrier frequency f0 =
22 MHz, and modulation on amplitude at FM = 1 kHz.
The IS was a periodically repeating transient process
with the pulse width τp = 5 ns, rise-time τr = 0.45 ns, and
with an exponent-like decay. The IS repetition frequen-
cy, Fr = 1 kHz.
3.2. RF RECEIVER TESTS IN THE ABSENCE
OF INFORMATION SIGNAL
The character of high-frequency amplifier (HFA) re-
sponse. The HFA response to impact of a unipolar vid-
eo-USP was qualitatively equal for IS with a wide range
of characteristics (Uin i = 0.001…0.1 V, τr = 0.45 ns, and
τp = 1…500 ns). The amplitude of the RR response var-
ied proportionally to the amplitude of the USP IS im-
pact. In this case, the width of the response signals τres
was practically unchanged and exceeded τp by more
than 100 times.
The HFA response to single USP IS with a relatively
small amplitude (τp < f0
-1, Uin i < 0.05 V) had the form of
damped sinusoid, which is a typical response of high-Q
system to shock impact of USP IS with the decrement
proportional to the system quality factor (Q ~ 25…30),
Fig. 2,a. The period of the sinusoid signal corresponded
well to the resonant frequency f0 of the RR input RF
circuit. Thus, τres(HFA) ≈ Q/2f0. If the USP IS ampli-
tudes was high enough (τp < f0
-1, Uin i > 0.05 V), the
shape of the damped sine was distorted, indicating the
appearance of nonlinear distortions.
Variation in the unipolar USP IS width significantly
changed the response envelope. The distortion of the
HFA response was determined by the interference of the
leading and trailing edges of the impact signal. For
τp > τre(HFA), the impact of each edge of the IS had an
independent character, so the efficiency of the interfer-
ence from each edge was maximum. At smooth varia-
tion in the IS width τp, the phase of the response signals
from leading and trailing edges could coincide at the
time intervals of f0
-1. For different IS widths, when the
delay time between the pulse edges (measured in units
of the reception frequency f0
-1) were multiples of f0
-1, a
minimum(or maximum) efficiency of the impact on the
receiver NB reception unit was observed.
The intermediate-frequency amplifier (IFA) re-
sponse. The dynamics of the IFA response to the impact
of short edges of USP IS was qualitatively consistent
with the HFA response. The response width of the IFA
to IS significantly exceeded the URF response. Fig. 2,b
shows the response of the IFA when τp << f0
-1 <<
τres(HFA). Like the HFA excitation, the IFA response
signal envelope suffered irregular changes due to the
phase-shifted effect of the leading and trailing edges of
the IS for its sufficiently long width, τp > τres(HFA). At
the same time, the structure of the response at the IFA
output was more complex than at the HFA output. It
was distinguished by the presence of 2 components: (i)
the response of the IF amplifier with the conversion
frequency fint = f0 - fh = 10.7 MHz, where fh is the local
oscillator frequency, and (ii) the low-frequency ampli-
tude modulation of the signal. Due to a high Q-factor of
the IFA unit, its response width τres(IFA) >> τres(HFA)
and reached 250 μs. The measured period, ТМ ≈ 80 μs,
of the LF modulation of the response corresponded to a
frequency that was about a half of the passband fre-
quency of the IF amplifier in the mode of the average
passband (25 kHz), fM = TM
-1 ≈ 1/2∆f(IFA) = 12.5 kHz.
The dynamics of the receiver’s low-frequency ampli-
fier (LFA) response had significant differences in com-
parison with the responses of two previous RR units of
HF and IF amplification. Under the impact of a series of
USP IS, the LFA output to each of the signals had a
characteristic aperiodic response, Fig. 2,c. In this case,
the LFA response width was approximately equal to the
whole width of the IFA response. An increase in the IS
repetition frequency to a value comparable to the maxi-
mum frequency of the LFA spectrum led to the overlap
of the response-signals and appearance of the LFA per-
manent failure.
3.3. COMBINED RECEPTION
OF INTERFERENCE AND INFORMATION
SIGNALS
The effect of USP IS changed significantly when a
continuous harmonic IFS and USP IS were received
simultaneously (see Table 3, mode III). The tests were
ISSN 1562-6016. ВАНТ. 2018. №4(116) 125
carried out in conditions of receiving the amplitude and
frequency modulated IFS. The effect of a stationary
harmonic IFS (FAM(FM) = 1 kHz) led to the result qualita-
tively different from that of previous tests. Briefly, it
can be considered as stabilization of the RR operation
due to the action of automatic gain control. In this case,
the modes of weak and strong IFS differed greatly. If
the IFC level at the RR input Uin inf exceeded the noise
level Un by 10…15 dB, the AGC suppressed the RR
response to repetitive or single USP IS. For typical rela-
tion values Uin i/Uin inf = 1000...2000, the interference
signal at the IFA output was significantly lower (up to
20 dB) than the information signal. In this case, the RR
functional upset did not occur. In the opposite case,
when the IFS amplitude Uin inf was below a certain criti-
cal level (≤10 dB Un), the action of USP IS resulted in
blinding the receiver for the time τres, which is charac-
teristic of only a sole USP IS impact.
With the same amplitude of the responses to IS and
IFS recorded at the RR output (Uout i /Uout inf ≈1), the
ratio of the amplitudes of the input signals was high, Uin i
/Uin inf =500…2000, see Fig. 2,c. This ratio set the mini-
mum IS amplitude, which produced the RR functional
upset in the combined mode of receiving the IS and IFS.
Large value of the ratio was due to a low spectral power
density of the interference in the IFS frequency range,
which, because of the large frequency band of the USP
IS (up to 2 GHz) did not exceed the level of
10–8 W/MHz. In spite of this, the USP IS energy equiva-
lent was very small W = τp(Uin i)2/2Rin ~ 10–14 J in the
tests indicating principally high energy efficiency of the
USP interference in modern electromagnetic environ-
ment.
3.4. TESTS OF SHF RECEIVING UNITS
Testing the receivers with the operating frequencies
of 2.0, 3.1 and 9.3 GHz affected by USP IS (see Table 3,
modes I, b, II and III) showed that the character of their
responses were qualitatively consistent with the picture of
a functional upset described above, but the structure of
the responses turned out to be much more complicated.
The parts of the SHF radio-tracts had a modular de-
sign and were manufactured as matched strip-lines with
installed active and passive elements. At the USP IS
amplitude exceeding the level of the RR linear operation
mode, the output signal of the low-noise amplifier
(LNA) demonstrated a complex nonlinear response.
Due to short pulse width of the IS, the dimensional ef-
fects in the SHF modules turned out to be significant.
This produced a condition for a multiple-path IS coupling
to the parts of the radio-tract associated with delays of the
reflected signals. In this case, several complex SHF ac-
tive parts such as multistage solid-state protective devices
(PD) and LNA or vacuum TWT demonstrated the ap-
pearance of the output signals with τres >> τp.
Fig. 3 demonstrates the RR response (f0 = 9.3 GHz)
to USP interference (τp = 1.2 ns, τr = 0.2 ns) at several
characteristic points of the SHF radio-tract: panel (a) at
the antenna output, panel (b) at the output of the LNA
(in linear amplification mode), panel (c) at the output of
the LNA (in non-linear amplification mode). As can be
seen, there are several time scales (confirmed by spec-
tral data) in the fine structure of the responses, indicat-
ing a non-stationary character of the signal transmission
conditions, multiple scattering, and interference of the
signal components in the radio-tract.
a b c
Fig. 3. The SHF receiver (9.3 GHz) response signals
to USP IS (τp= 1.2 ns, τr = 0.2 ns): (a) antenna output;
(b) LNA output, linear operation mode; (c) LNA output,
non-linear operation mode
The detailed analysis of the RR response-signals dy-
namics due to the affect of USP IS of various types
showed that their complexity was a result of simultaneous
development of a number of effects [16]: (i) distortion of
the intense input signals when its amplitude was limited
in a PD that initiated the excitation of nonlinear oscilla-
tions; (ii) non-linear distortions of the UWB impulse sig-
nal and excitation of chaotic oscillations, caused by the
radio-signal components interacting in the active element.
CONCLUSIONS
1. The Kharkiv V. N. Karazin National University
Radiophysical Observatory includes a broad set of radar
and radio instrumentation. The performance specifica-
tions of the instrumentation and the software employing
modern signal processing techniques provide verified
high temporal resolution measurements required for
monitoring the highly variable space atmosphere inter-
action region. The Observatory can function both au-
tonomously and be successfully used for ground-based
support for space missions, and for the scientific project
“IonoSat-Micro” in particular. In planned radio-sensing
experiments, new radar with characteristics (pulse pow-
er of up to several hundred megawatts and pulse width
of about 10 ns) can create an extreme electromagnetic
environment. Thus, modern metrological verification
and certification of remote sensing equipment is re-
quired to minimize the radar impact on radio-electronic
equipment of the observatory.
2. The laboratory tests of radio receivers of different
frequency range have shown that intense ultrashort elec-
tromagnetic impulses, due to a high penetrating quality
and low upset threshold levels are the most dangerous
factor of the modern electromagnetic environment.
3. The efficiency of excitation of nonlinear respons-
es in unprotected radio receivers observed even for a
small-amplitude interfering USP, is determined by
combination of the their temporal and frequency charac-
teristics: the pulse width, pulse rise-time, and the repeti-
tion frequency for video signals, as well as the carrier
frequency for radio signals.
4. Taking into account the features of a receiver re-
sponse to USP interference, it is possible to choose cor-
rectly the methods and means for the receiver protec-
tion, and also to optimize terrestrial layout of complex
active radio-frequency electronics, such as, for example,
radars for sub-satellite monitoring of geospace and ion-
osphere sensing.
ISSN 1562-6016. ВАНТ. 2018. №4(116) 126
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Article received 04.06.2018
АСПЕКТЫ ЭЛЕКТРОМАГНИТНОЙ СОВМЕСТИМОСТИ ПРИ ИОНОСФЕРНОМ ДИСТАНЦИОННОМ
ЗОНДИРОВАНИИ В РАДИОФИЗИЧЕСКОЙ ОБСЕРВАТОРИИ ХАРЬКОВСКОГО НАЦИОНАЛЬНОГО
УНИВЕРСИТЕТА
И.И. Магда, Л.Ф. Черногор
Исследуются характерные виды реакций радиоприемных устройств различных типов и частотного диапазона в условиях
приема интенсивных сигналов сверхкороткой длительности, а также в условиях комбинированного приема информационных
сигналов и помеховых сигналов сверхкороткой длительности. Проведен анализ возможного сценария сбоев радиоприемных
устройств радиофизической обсерватории ХНУ в условиях сеанса дистанционного радиозондирования ионосферы, в
котором используется новое оборудование с импульсной мощностью до нескольких сотен мегаватт и длительностью
импульса около 10 нс. В тестах приемных устройств использованы характеристики помеховых сигналов, которые достаточно
полно отражают возможные условия предполагаемых экспериментов по радиозондированию ионосферы. Предполагается,
что результаты исследований будут способствовать разработке различных превентивных мероприятий по электромагнит-
ной защите радиоэлектронной аппаратуры обсерватории.
АСПЕКТИ ЕЛЕКТРОМАГНІТНОЇ СУМІСНОСТІ ПРИ ДИСТАНЦІЙНОМУ ЗОНДУВАННІ ІОНОСФЕРИ
В РАДІОФІЗИЧНІЙ ОБСЕРВАТОРІЇ ХАРКІВСЬКОГО НАЦІОНАЛЬНОГО УНІВЕРСИТЕТУ
І.І. Магда, Л.Ф. Черногор
Досліджуються характерні види реакції радіоприймальних пристроїв різних типів і частотного діапазону в умовах при-
йому інтенсивних сигналів надкороткої тривалості, а також в умовах комбінованого прийому інформаційних сигналів і
перешкоджаючих сигналів надкороткої тривалості. Проведено аналіз можливого сценарію збоїв радіоприймальних при-
строїв радіофізичної обсерваторії ХНУ в умовах сеансу дистанційного радіозондування іоносфери, в якому використову-
ється нове обладнання з імпульсною потужністю до декількох сотень мегават і тривалістю імпульсу близько 10 нс. У тестах
приймальних пристроїв використані характеристики перешкоджаючих сигналів, які досить повно відображають можливі
умови передбачуваних експериментів з радіозондування іоносфери. Передбачається, що результати досліджень будуть
сприяти розробці різних превентивних заходів щодо електромагнітного захисту радіоелектронної апаратури обсерваторії.
https://www.researchgate.net/researcher/2045551452_S_B_Bludov
https://www.researchgate.net/researcher/2005151082_N_P_Gadetskii
https://www.researchgate.net/researcher/30712345_K_A_Kravtsov
https://www.researchgate.net/researcher/2005151082_N_P_Gadetskii
https://www.researchgate.net/researcher/2005151082_N_P_Gadetskii
Test signals
characteristics
I,а
II
3.4. Tests of SHF receiving units
12. А.А. Vedmidsky, А.D. Antonov. Features of damage effect of the nanosecond EMP on various radio-elements (in Russian) // XIII Sci. Tech. Conf. on on protection of structures from damaging action of EMP. Scientific and technical collection of report...
АСПЕКТЫ ЭЛЕКТРОМАГНИТНОЙ СОВМЕСТИМОСТИ ПРИ ИОНОСФЕРНОМ ДИСТАНЦИОННОМ ЗОНДИРОВАНИИ В РАДИОФИЗИЧЕСКОЙ ОБСЕРВАТОРИИ ХарьковскОГО национальнОГО университетА
И.И. Магда, Л.Ф. Черногор
АСПЕКТи ЕЛЕКТРОМАГНІТНОЇ Сумісності ПРИ ДИСТАНЦІЙНОМУ ЗОНДуванні ІОНОСФЕРИ В радіофізичній Обсерваторії ХаркІвськОГО національнОГО університету
І.І. Магда, Л.Ф. Черногор
Досліджуються характерні види реакції радіоприймальних пристроїв різних типів і частотного діапазону в умовах прийому інтенсивних сигналів надкороткої тривалості, а також в умовах комбінованого прийому інформаційних сигналів і перешкоджаючих сигналів ...
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