Analysis of three differential gpr systems for subsurface imaging
The goal of this work is to analyze and compare possibilities of imaging using differential antenna systems with receiving antennas displaced symmetrically with respect to the transmitting antenna along three orthogonal directions. To this end, synthetic radargrams are generated by the finite-differ...
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Інститут радіофізики і електроніки ім. А.Я. Усикова НАН України
2014
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| Цитувати: | Analysis of three differential gpr systems for subsurface imaging / L.A. Varianytsia-Roshchupkina, G. Gennarelli, F. Soldovieri, G.P. Pochanin // Радіофізика та електроніка. — 2014. — Т. 5(19), № 4. — С. 48-55. — Бібліогр.: 19 назв. — англ. |
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nasplib_isofts_kiev_ua-123456789-1061472025-02-09T23:35:11Z Analysis of three differential gpr systems for subsurface imaging Анализ трех дифференциальных конфигураций георадаров с точки зрения качества отображения подповерхностных объектов Аналіз трьох диференційних конфігурацій георадарів відносно якості відображення підповерхневих об’єктів Varianytsia-Roshchupkina, L.A. Gennarelli, G. Soldovieri, F. Pochanin, G.P. Распространение радиоволн, радиолокация и дистанционное зондирование The goal of this work is to analyze and compare possibilities of imaging using differential antenna systems with receiving antennas displaced symmetrically with respect to the transmitting antenna along three orthogonal directions. To this end, synthetic radargrams are generated by the finite-difference time-domain forward solver for each measurement setup. After that a microwave tomographic approach is applied to process the scattered field differential data and to facilitate the comparison among these systems. As a result, it was obtained that the system with antennas displaced along the vertical axis is the only one capable to provide a reliable image regardless of the shape of the object. The performed studies have shown the prospects of such system application in the practical GPR problems. Цель работы состоит в том, чтобы проанализировать и сравнить визуализационные возможности дифференциальных конфигураций антенных систем, составленных из приемной антенны – передающей антенны – приемной антенны, в которых приемные антенны симмет-рично смещены относительно передающей антенны вдоль трех ортогональных направлений. Для этого выполнено FDTD-моделирование радарограмм для каждой измерительной конфигурации. Для обработки дифференциальных данных полей рассеяния и сравнения между системами использован метод микроволновой томографии. Установлено, что только система с вертикально разнесенными антеннами способна обеспечить наиболее реалистичное изображение независимо от формы исследуемого объекта. Проведенные исследования показали перспективность применения такой системы в практических задачах георадиолокационного зондирования. Мета роботи полягає у тому, щоб проаналізувати й порівняти візуалізаційні можливості диференційних конфігурацій антенних систем, що складаються з приймальної антени – передавальної антени – приймальної антени, у яких приймальні антени симетрично зміщені відносно передавальної антени вздовж трьох ортогональних напрямків. Для цього виконано FDTD-моделювання радарограмм для кожної вимірювальної конфігурації. Для обробки диференційних даних полів розсіювання та порівняння між системами використано метод мікрохвильової томографії. Встановлено, що тільки система з вертикально рознесеними антенами здатна забезпечити найбільш реалістичне зображення незалежно від форми досліджуваного об’єкта. Проведені дослідження показали перспективність застосування такої системи в практичних задачах георадіолокаційного зондування. 2014 Article Analysis of three differential gpr systems for subsurface imaging / L.A. Varianytsia-Roshchupkina, G. Gennarelli, F. Soldovieri, G.P. Pochanin // Радіофізика та електроніка. — 2014. — Т. 5(19), № 4. — С. 48-55. — Бібліогр.: 19 назв. — англ. 1028-821X https://nasplib.isofts.kiev.ua/handle/123456789/106147 517.962: 517.968.2: 537.874.6: 621.391.1 en Радіофізика та електроніка application/pdf Інститут радіофізики і електроніки ім. А.Я. Усикова НАН України |
| institution |
Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| collection |
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| language |
English |
| topic |
Распространение радиоволн, радиолокация и дистанционное зондирование Распространение радиоволн, радиолокация и дистанционное зондирование |
| spellingShingle |
Распространение радиоволн, радиолокация и дистанционное зондирование Распространение радиоволн, радиолокация и дистанционное зондирование Varianytsia-Roshchupkina, L.A. Gennarelli, G. Soldovieri, F. Pochanin, G.P. Analysis of three differential gpr systems for subsurface imaging Радіофізика та електроніка |
| description |
The goal of this work is to analyze and compare possibilities of imaging using differential antenna systems with receiving antennas displaced symmetrically with respect to the transmitting antenna along three orthogonal directions. To this end, synthetic radargrams are generated by the finite-difference time-domain forward solver for each measurement setup. After that a microwave tomographic approach is applied to process the scattered field differential data and to facilitate the comparison among these systems. As a result, it was obtained that the system with antennas displaced along the vertical axis is the only one capable to provide a reliable image regardless of the shape of the object. The performed studies have shown the prospects of such system application in the practical GPR problems. |
| format |
Article |
| author |
Varianytsia-Roshchupkina, L.A. Gennarelli, G. Soldovieri, F. Pochanin, G.P. |
| author_facet |
Varianytsia-Roshchupkina, L.A. Gennarelli, G. Soldovieri, F. Pochanin, G.P. |
| author_sort |
Varianytsia-Roshchupkina, L.A. |
| title |
Analysis of three differential gpr systems for subsurface imaging |
| title_short |
Analysis of three differential gpr systems for subsurface imaging |
| title_full |
Analysis of three differential gpr systems for subsurface imaging |
| title_fullStr |
Analysis of three differential gpr systems for subsurface imaging |
| title_full_unstemmed |
Analysis of three differential gpr systems for subsurface imaging |
| title_sort |
analysis of three differential gpr systems for subsurface imaging |
| publisher |
Інститут радіофізики і електроніки ім. А.Я. Усикова НАН України |
| publishDate |
2014 |
| topic_facet |
Распространение радиоволн, радиолокация и дистанционное зондирование |
| url |
https://nasplib.isofts.kiev.ua/handle/123456789/106147 |
| citation_txt |
Analysis of three differential gpr systems for subsurface imaging / L.A. Varianytsia-Roshchupkina, G. Gennarelli, F. Soldovieri, G.P. Pochanin // Радіофізика та електроніка. — 2014. — Т. 5(19), № 4. — С. 48-55. — Бібліогр.: 19 назв. — англ. |
| series |
Радіофізика та електроніка |
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РРААССППРРООССТТРРААННЕЕННИИЕЕ РРААДДИИООВВООЛЛНН,, РРААДДИИООЛЛООККААЦЦИИЯЯ ИИ ДДИИССТТААННЦЦИИООННННООЕЕ ЗЗООННДДИИРРООВВААННИИЕЕ
_________________________________________________________________________________________________________________
__________
ISSN 1028−821X Радиофизика и электроника. 2014. Т. 5(19). № 4 © ИРЭ НАН Украины, 2014
UDC 517.962: 517.968.2: 537.874.6: 621.391.1
L. A. Varianytsia-Roshchupkina, G. Gennarelli*, F. Soldovieri*, G. P. Pochanin
O. Ya. Usikov Institute for Radiophysics and Electronics of NAS of Ukraine
12, Ac. Proskura St., Kharkiv, 61085, Ukraine
E-mail: vla@ire.kharkov.ua; gpp@ire.kharkov.ua
*Institute for Electromagnetic Sensing of the Environment of CNR of Italy
328,Via Diocleziano, Naples, 80124, Italy
E-mail: gennarelli.g@irea.cnr.it; soldovieri.f@irea.cnr.it
ANALYSIS OF THREE DIFFERENTIAL GPR SYSTEMS FOR SUBSURFACE IMAGING
Quality of the radar images of the detected objects directly depends on the quality of the obtained GPR data. One of the ways to
increase the information content of such data is to use not traditional (monostatic, bistatic) but alternative (e. g., differential) antenna systems.
The goal of this work is to analyze and compare possibilities of imaging using differential antenna systems with receiving antennas displaced
symmetrically with respect to the transmitting antenna along three orthogonal directions. To this end, synthetic radargrams are generated by
the finite-difference time-domain forward solver for each measurement setup. After that a microwave tomographic approach is applied to
process the scattered field differential data and to facilitate the comparison among these systems. As a result, it was obtained that the system
with antennas displaced along the vertical axis is the only one capable to provide a reliable image regardless of the shape of the object.
The performed studies have shown the prospects of such system application in the practical GPR problems. Fig. 14. Table 1. Ref.: 19 titles.
Key words: GPR, differential antenna systems, FDTD, microwave tomography.
The choice of the optimal Ground
Penetrating Radar (GPR) system configuration is a
crucial factor for the imaging capabilities of
subsurface radar [1, 2]. The bistatic antenna system
with a common-offset transmitter and receiver pair is
the most commonly adopted solution for a modern
GPR. The main drawback of such system is that the
signal collected by the receiver (total signal) includes
not only a signal scattered from the object, but also
the direct signal from the transmitter to the receiver
(which does not convey any information about the
target). Usually, the amplitude of the direct signal is
much larger than that reflected by the object.
It complicates the target detection. In addition, this
coupling limits the dynamic range of the GPR, and
powerful direct signal may damage a sensitive input
circuit of the receiver.
In order to eliminate the incident field from
the total field signal, the multi-bistatic differential
systems were suggested in [3–7]. The basic principle
of differential systems is in the use of central
symmetry in configurations like transmitter – receiver –
transmitter (TRT) or receiver – transmitter – receiver (RTR).
The couplings of two transmitters in the TRT-system
cancel each other at the receiver. For the RTR-system,
the direct signal from the transmitter is canceled at
two receivers by subtraction of the total signals.
In the case of a differential system with
horizontal spacing between the antennas, if the
ground is homogeneous and all interfaces are
uniform, the signals reflected by the interfaces are
also canceled out at the input of receiver.
Theoretical studies in papers [3–7] have
shown a high efficiency of the application of
differential antenna systems for GPR investigations.
However, the practical implementation of the
proposed ideas is complicated by the difficulties of
creation of the geometrically and physically
completely symmetric system. A slightest inaccuracy
in the construction or discrepancy in characteristics of
pairs of components can have a catastrophic impact
on the performance of the whole system. So, the
difficulties associated with practical implementation
of the system limit the possibility of its application for
real GPR problems solving.
One of the earliest real developments of the
differential antenna system with horizontally
separated antennas is described in [8]. As previously
noted, such system could be useful for the detection
of localized buried targets. However, such systems are
unsuitable for detecting the extended buried targets
like layers. Accordingly, a differential system with
vertically spaced antennas was suggested in [9–11].
In [8–11] it was proposed to subtract signals coming
from two receiving antennas in the summator.
It allowed getting zero direct coupling signal at the
input of the receiver. In practice, such antenna system
(GPR “ODYAG”) made it possible to reach the
decoupling level of about –100 dB [10].
The preliminary theoretical comparisons of
imaging possibilities of the horizontal and vertical
differential systems were recently carried out in case
of the conducting objects located in a 2D free space
scenario [12]. In particular, it was shown that a more
reliable image of the object can be generally obtained
by using the receiving antennas displaced vertically.
In case of horizontally spaced receivers only edges of
targets can be imaged.
The aim of this work is to extend the
previous analysis to the 3D-geometry in the case of
conductive and dielectric objects. We consider the
sounding of different geometrical structures by three
differential GPR systems (Fig. 1) and compare their
imaging performance. Synthetic scattered field data
are generated by means of an ad-hoc developed
Finite-Difference Time-Domain (FDTD) code [13]. In
Л. А. Варяница-Рощупкина и др. / Анализ трех дифференциальных…
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49
addition, in order to improve the interpretation of the
results with respect to radargrams, the data are
processed by means of the microwave tomographic
approach similar to the one reported in [7] for the 2D
case. Reconstruction results are shown to support the
analysis and compare the systems.
1. Problem statement. For the sake of
simplicity, we consider the 3D free-space scenario
depicted in Fig. 1, a. A target Q stands in the
investigation domain D, and the scene is probed by an
antenna system moving on the survey plane Γ at z = 0
under a reflection configuration. The distance
between the nearest edge of the object Q and the
survey plane Γ is denoted as h.
Fig. 1, b depicts three differential antenna
systems consisting of the transmitting antenna T and a
pair of receiving antennas R symmetrically spaced
with respect to T along x, y or z at distance hs. We
denote each system using the following notation:
(Rx– T Rx+) and (Ry– T Ry+) are “horizontal” Systems I
and II respectively, (Rz– T Rz+) is a “vertical”
System III. Each antenna is simulated here as a
Hertzian dipole directed along the y-axis. These three
antenna systems move simultaneously along survey
lines in Γ-plane parallel to the x-axis at different
values of the y0 coordinate.
Fig. 1. Geometry of the imaging problem
The transmitting dipole is excited by the current
pulse I(t) with temporal variation corresponding to
the time derivative of Gaussian pulse (Ricker
function):
( )2)4/(1 )(exp)(2)( δςδς ς −−−−= ttetI , (1)
where 222 fπς = and ,/1 f=δ with f being the
central frequency of the pulse.
In this work, we focus on imaging three
types of objects. The first one is a rectangular bar with
sizes zyx lll ×× , the second one is a sphere of radius l
and the last one is a combination of two rectangular
bars with sizes 111
zyx lll ×× and 222
zyx lll ×× spaced by
distance h1 (Fig. 2). For the bar, both cases of
dielectric (relative permittivity ε = 1.3) and perfectly
conducting targets will be addressed; while only
metallic sphere and metallic combined target are
considered.
Fig. 2. Geometry of the targets Q
These types of object have been selected in
order to evaluate the systems’ performance for both
the localized and elongated targets.
2. Microwave tomographic approach.
In this section, we describe the inversion approach
used to retrieve the object profile from the scattered
field data.
We denote with )0,,( 000 yxr = the
coordinates of the transmitting antenna T. Moreover,
)0,,( 00 yhxr sx ∓∓ = , )0,,( 00 sy hyxr ∓∓ = , and =∓zr
),,( 00 shyx ∓= are the positions of the receivers in
Systems I, II, III, respectively.
The data to be inverted are the difference of
total fields measured by receivers while the antennas
move along Γ. To simplify the problem, we adopt a
linearized inverse scattering model based on the Born
approximation [7, 14, 15]. Accordingly, the functional
relationships between the frequency domain data and
the target in D are linear. In particular, we have:
( ) ( ) ( )
( )
( ) ( ) ( ) y
inc
D x
x
x
tot
yx
tot
y
I
y
erdrfrrE
frrG
frrG
k
frEfrEfrE
×′′′×⎥
⎦
⎤
⎢
⎣
⎡
′−
−′
=
=−=Δ
∫∫∫
+
−
+−
χ,,
,,
,,
,,,
0
2
0
0
(2)
for System I. In eq. (2), f is the work frequency, tot
yE
is the y-component of the total field at the receivers
Rx–, Rx+; k0 is wave number of free-space; G is the
dyadic Green’s function in free-space [16]; incE is
the incident field at the point ),,( zyxr ′′′=′ in D; and
1−= εχ is the unknown object contrast, where ε is a
relative permittivity of the object; ;zdydxdrd ′′′=′
)0,1,0(=ye is the y-directed unit vector. Functional
relationships for ),( 0
II frEyΔ and ),( 0
III frEyΔ
relevant to Systems II and III can be written in a
similar way.
Л. А. Варяница-Рощупкина и др. / Анализ трех дифференциальных…
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50
Once the differential scattered field data
IIIII,I,
yEΔ have been gathered, the imaging problem
amounts to performing the inversion of the
corresponding linear operators with respect to the
unknown χ. Such a problem is ill-posed and a
regularized solution is obtained by applying the
Truncated Singular Value Decomposition (TSVD)
algorithm [17]:
,
,
),(
0
∑
=
Δ
=′′
N
n
n
n
ny u
vE
zx σχ (3)
where NT is a truncation index determining the
“degree of regularization” of the solution, ⋅⋅,
denotes a scalar product, { }∞=0nnσ is a set of singular
values in non-increasing order, { }∞=0nnv and { }∞=0nnu
are basis functions in the data and unknown spaces,
respectively [17].
3. Numerical simulation. The radar signals
are computed by an ad-hoc developed 3D-code [13]
based on the FDTD-method. Perfectly absorbing
boundary conditions [18] are used in order to limit the
computational domain. Image profiles (В-scans) are
obtained by the program “GPR ProView” of GPR
data processing [19]. These program modules have
been developed and implemented in O. Ya. Usikov
Institute for Radiophysics and Electronics of NAS of
Ukraine. The method of variable density [1] is used
for result visualization.
For the simulations, we choose the following
input parameters:
− source T is located at the distance h = 0.3 m
from the object;
− distance hs between T and the receivers is fixed
to 0.05 m;
− central frequency of the pulse f = 1 GHz;
− object sizes are 4.02 === zyx lll m; 1.0=l m
and 4.042 111 === xzy lll m and === 222 2 zyx lll
2.0= m; the distance h1 between the objects in pair is
0.1 m.
Other parameters related to the problem are
listed in the Table below.
Simulation parameters
Parameter Value
Size of the measurement domain Γ 1×1 m2
Transmitter measurement step 0.1 m
Number of measurement points 11×11
Time window for each trace 8 ns
Number of time samples for each trace 416
3.1. Synthetic radargrams. The radargrams
corresponding to the dielectric and conducting bars
are shown in Fig. 3 and 4 for different antenna
systems and two survey lines. The same is done for
the conducting sphere and two conducting bars in
Fig. 5 and 6.
Fig. 3. Radargrams of the dielectric bar
Fig. 4. Radargrams of the conducting bar
Fig. 5. Radargrams of the conducting sphere
Fig. 6. Radargrams of a pair of conducting bars
Л. А. Варяница-Рощупкина и др. / Анализ трех дифференциальных…
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51
From the analysis of radargrams, it is
possible to make some common conclusions:
− When using Systems I, II and III instead of
the traditional multi-bistatic configuration, the
radargrams contain only the signals scattered by the
objects. In this way, the object detection is possible
without any additional processing. A quite different
situation occurs when the survey line is in the plane
of object symmetry and receiving antennas are
symmetrical to this plane; in this case, no object
response is observed in the radargram (the case of
System II with y = 0 in Fig. 3–5).
− Because of the symmetry problem, the System
I cannot image the middle part of the object.
− In case of the antenna system moving on the
bottom edge of the survey plane (y = –0.5), the
position and geometrical characteristics of the
reflecting object are similar for System II and System
III. The existing difference in extension of reflecting
surfaces has only a minor influence on the image of
the object in radargram and is almost undistinguished
by eye (see Fig. 3–6).
The analysis of radargams of dielectric and
conducting bars shows that the presence of the
rectangular bar in radargram can be detected by local
horizontal fascias when using Systems II and III, and
by sections of hyperbolic curves that indicate edges
of the bar when using System I.
In both cases (dielectric and conducting
objects), radargrams corresponding to the bottom
edge of the survey plane (y = –0.5) provide
information about both front and back sides of bars.
While the central location of the antenna system
survey line (y = 0) provides information about both
front and back sides of bars in case of the dielectric
object only (Except for System II). In this case we
can detect only the front side of the conducting
object.
In case of the dielectric object, spurious
reflections from the absorbing boundary conditions
(see Fig. 3, oblique line segments in the time
interval [2, 4] ns at y = –0.5 m and [5, 8] ns at
y = 0 m), are more significant.
We can note that the signals of maximal
amplitude are observed in System III when the
antenna system is placed over the center of the target.
When the antenna System II is placed over the center
of the target, the reflected signal is of zero amplitude.
The radargrams corresponding to conducting
objects of different geometrical shapes are shown in
Fig. 4–6 for different antenna systems and survey
lines. We can state that:
− The spherical object in the radar image is
represented as a hyperbolic curve (for all types of
antenna systems).
− Two bars in the radar image are represented as
a series of hyperbolic curves (for all types of antenna
systems). And it can be noticed that at the central
location of the antenna system survey line (y = 0)
different antenna systems detect objects in a different
way: System I detects one object, System II detects
another one, and System III combines information
about both of them.
− Representations of objects of different
geometrical forms are very much similar for System I
(they are always hyperbolic curves) and they can be
different for System II and System III. But in any
case it is difficult to recognize the object geometry
without additional processing (especially in case of
two closely spaced objects, see Fig. 6).
3.2. Tomographic reconstruction. The time
domain scattered field data collected under
configurations I, II and III have been processed
through the tomographic approach. The
corresponding software is developed and
implemented in the Institute for Electromagnetic
Sensing of the Environment of CNR of Italy.
The working frequency band [500,
2 000] MHz is considered and sampled with a step of
250 MHz. The targets are centered in the investigation
domain D = [–0.4, 0.4]×[–0.4, 0.4]×[0.2, 0.6] m3,
which is discretized into voxels with size
Δx = Δy = 0.05 m and Δx = 0.025 m. The truncation
index of the TSVD inversion scheme in (3) is selected
in a way to filter singular values that are 25 dB lower
than the maximum one.
The tomographic images of different objects
are shown in Fig. 7–14.
Dielectric and conducting bars. The
tomographic images shown in Fig. 7 and 8 refer to the
dielectric bar.
It can be seen that System I allows detecting
the edges aligned with the y-axis. System II permits to
identify the edges directed along the x-axis.
System III allows reconstructing the full geometry of
both the upper and lower surface of the object.
Therefore, System III allows getting clearer image of
the object and identifying better its shape.
As expected, the same considerations hold
for the metallic bar (Fig. 9 and 10), except for the
fact that now it is impossible to get information about
the lower surface because of full reflection by the
upper and lateral sides of the object.
Conducting sphere. The results of
microwave tomographic reconstruction for this kind
of target are presented in Fig. 11 and 12.
For System I, the tomographic image of the
spherical object is three elliptic objects elongated in
y-direction and spaced in x-direction. For System II,
the tomographic image of the spherical object is three
elliptic objects elongated in x-direction and spaced in
y-direction. System III allows getting a clearer image
of the object and to identify better its spherical shape.
Two conducting bars. Resolution and
detection of closely set targets is one of the important
problems of modern GPR. In Fig. 13 and 14, the
tomographic images of such kind of targets (two
conducting bars) are presented.
Л. А. Варяница-Рощупкина и др. / Анализ трех дифференциальных…
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52
Fig. 7. Z-slices of the tomographic reconstruction of the dielectric bar
Fig. 8. Isosurface plot of the tomographic reconstruction of the dielectric bar
Fig. 9. Z-slices of the tomographic reconstruction of the metallic bar
Fig. 10. Isosurface plot of the tomographic reconstruction of the metallic bar
Л. А. Варяница-Рощупкина и др. / Анализ трех дифференциальных…
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53
Fig. 11. Z-slices of the tomographic reconstruction of the metallic sphere
Fig. 12. Isosurface plot of the tomographic reconstruction of the metallic sphere
Fig. 13. Z-slices of the tomographic reconstruction of a pair of metallic bars
Fig. 14. Isosurface plot of the tomographic reconstruction of a pair of metallic bars
___________________________________________
We can state that it is very difficult to detect
the presence of the second (“x-oriented”) object for
System I. For System II, it is almost impossible to
detect the presence of the first (“y-oriented”) object.
Л. А. Варяница-Рощупкина и др. / Анализ трех дифференциальных…
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54
In order to detect these low contrast objects the
threshold value has to be fixed at a quite low value,
which is comparable with the level of noise.
But System III similarly to previous cases
gives us a quite clear image of the objects and allows
identifying its shape.
Conclusions. In this work, we have
compared the capabilities of three differential GPR
systems with symmetrical receiving antennas
displaced along three orthogonal directions with
respect to the transmitting antenna. Synthetic radar
images have been computed and analyzed.
It has been shown:
− When using Systems I, II and III instead of
the traditional multi-bistatic configuration, the object
detection is possible without any additional
processing, because the radargrams do not contain
masking high power signals of direct coupling.
Except for the situation when the survey line is in the
plane of the object symmetry and receiving antennas
are placed symmetrically to this plane. In this case
the object becomes “invisible”.
− Objects of different geometrical shapes can
have different representations in radargrams (fascia,
hyperbolic curve). But in any case, it is difficult to
identify their geometries without additional
processing (especially in case of two closely spaced
objects).
The microwave tomographic approach has
proved to be a valuable tool to support the proposed
analysis. Indeed, it has been shown:
− In case of one rectangular bar, the target form
can be recovered, despite the fact that each system
can only provide information about a pair of object
surfaces. But the correct information about object
dimensions can be obtained for the dielectric bar
only, when using System III. For metal objects, size
measurement is possible for only two of three
coordinate directions (length, width, but not depth).
− For GPR investigations of such objects as a
sphere and especially a pair of bars, using the
differential systems with receivers lying in the
measurement plane leads to the loss of the
information about the shape and size of target. The
vertical spacing of receiving antennas allows getting
more reliable images of objects in such problems.
Thus, the analysis has revealed the
advantages of using a differential antenna system with
vertically spaced different antennas for reconstructing
the shape and dimensions of sounding objects in free
space. Thereby the performed studies have shown that
the application of such systems in the practical GPR
problems is very promising.
The research has been performed in the
framework of the Active and Passive Microwaves for
Security and Subsurface imaging (AMISS) EU
7th Framework Marie Curie Actions IRSES project
(PIRSES-GA-2010-269157).
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Рукопись поступила 21.11.2014.
Л. А. Варяница-Рощупкина, Дж. Дженнарелли,
Ф. Сольдовьери, Г. П. Почанин
АНАЛИЗ ТРЕХ ДИФФЕРЕНЦИАЛЬНЫХ
КОНФИГУРАЦИЙ ГЕОРАДАРОВ
С ТОЧКИ ЗРЕНИЯ КАЧЕСТВА ОТОБРАЖЕНИЯ
ПОДПОВЕРХНОСТНЫХ ОБЪЕКТОВ
Качество радиолокационных изображений обнару-
живаемых объектов напрямую зависит от качества полу-
чаемых георадиолокационных данных. Одним из путей
повышения информативности таких данных является
использование не традиционных (моностатической, бистати-
ческой), а альтернативных (к примеру, дифференциальных)
антенных систем. Цель работы состоит в том, чтобы про-
анализировать и сравнить визуализационные возможности
дифференциальных конфигураций антенных систем, состав-
ленных из приемной антенны – передающей антенны –
приемной антенны, в которых приемные антенны симмет-
рично смещены относительно передающей антенны вдоль
трех ортогональных направлений. Для этого выполнено
FDTD-моделирование радарограмм для каждой измери-
тельной конфигурации. Для обработки дифференциальных
данных полей рассеяния и сравнения между системами
использован метод микроволновой томографии. Установлено,
что только система с вертикально разнесенными антеннами
способна обеспечить наиболее реалистичное изображение
независимо от формы исследуемого объекта. Проведенные
исследования показали перспективность применения такой
системы в практических задачах георадиолокационного
зондирования.
Ключевые слова: GPR, дифференциальная антен-
ная система, FDTD, микроволновая томография.
Л. А. Варяниця-Рощупкіна, Дж. Дженнареллі,
Ф. Сольдов’єрі, Г. П. Почанін
АНАЛІЗ ТРЬОХ ДИФЕРЕНЦІЙНИХ
КОНФІГУРАЦІЙ ГЕОРАДАРІВ
ВІДНОСНО ЯКОСТІ ВІДОБРАЖЕННЯ
ПІДПОВЕРХНЕВИХ ОБ’ЄКТІВ
Якість радіолокаційних зображень об’єктів, що
треба виявити, безпосередньо залежить від якості одержу-
ваних георадіолокаційних даних. Одним із шляхів підвищення
інформативності таких даних є використання не традиційних
(моностатичної, бістатичної), а альтернативних (наприклад,
диференційних) антенних систем. Мета роботи полягає у
тому, щоб проаналізувати й порівняти візуалізаційні можли-
вості диференційних конфігурацій антенних систем, що
складаються з приймальної антени – передавальної антени –
приймальної антени, у яких приймальні антени симетрично
зміщені відносно передавальної антени вздовж трьох
ортогональних напрямків. Для цього виконано FDTD-моделю-
вання радарограмм для кожної вимірювальної конфігурації.
Для обробки диференційних даних полів розсіювання та
порівняння між системами використано метод мікрохвильової
томографії. Встановлено, що тільки система з вертикально
рознесеними антенами здатна забезпечити найбільш
реалістичне зображення незалежно від форми досліджуваного
об’єкта. Проведені дослідження показали перспективність
застосування такої системи в практичних задачах
георадіолокаційного зондування.
Ключові слова: GPR, диференційна антенна система,
FDTD, мікрохвильова томографія.
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