Analysis of the possibilities of using reflected radiation of ground-based radioelectronic devices from low-orbit Earth satellites

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Analysis of the possibilities of using reflected 
radiation of ground-based radioelectronic devices 
from low-orbit Earth satellites 
1
st
Kuanysh Alipbayev 
Institute of Telecommunications 
and Space Engineering 
Almaty University of Power 
Engineering and 
Telecommications named after G. 
Daukeyev 
Almaty, Kazakhstan 
[e-mail]
 
2
nd
Yenglik Mellatova 
Institute of Telecommunications 
and Space Engineering 
Almaty University of Power 
Engineering and 
Telecommications named after G. 
Daukeyev 
Almaty, Kazakhstan 
[e-mail]
 
3
rd
Angsagan Kenzhegarayeva 
Institute of Telecommunications 
and Space Engineering 
Almaty University of Power 
Engineering and 
Telecommications named after G. 
Daukeyev 
Almaty, Kazakhstan 
[e-mail]
 
4
th
Zhanna Suimenbayeva 
Institute of Telecommunications 
and Space Engineering 
Almaty University of Power 
Engineering and 
Telecommications named after G. 
Daukeyev 
Almaty, Kazakhstan,
[e-mail]
5
th
Komil Tashev 
Tashkent University of 
Information Technologies named 
after Muhammad al-Khwarizmi 
Tashkent, Uzbekistan 
[e-mail]
 
Abstract—High-speed communication lines are one of the 
priorities of the developed countries of the world today. The 
scale of the territory, the cost of construction, the remoteness of 
many objects and other factors prevents the laying of this type 
of communication everywhere and create prerequisites for the 
importance of further development of radio communication 
systems, both terrestrial and satellite. This article discusses an 
extensive analysis of the possibilities of building passive radar 
and space communication systems based on the re-reflection of 
signals from space objects in near-Earth orbit. The objectives 
of the article are to conduct a point analysis to derive a 
preference for the use of reflected radiation of ground-based 
radio-electronic means from low-orbit Earth satellites. 
Keywords—Low-orbit satellites, ground-based electronic 
means, passive radar, space debris. 
I. I
NTRODUCTION
Large territories, diverse landscape, low population density, 
high cost of construction and operation, as well as many 
critically important natural and man-made facilities scattered 
throughout our country, prevent the laying of high-speed fiber-
optic communication lines. Considering the above reasons, it is 
of interest to study the possibility of using space objects located 
in low Earth orbits as passive repeaters of the radiation of 
unauthorized ground-based electronic means for subsequent 
reception of reflected radiation. 
The development of space communications today has 
predetermined a new stage of information transmission. Thanks 
to the use of satellites, remote and hard-to-reach areas can be 
connected, and the Earth's surface can be monitored.
It is known that during the period of space exploration, the 
amount of space debris in near-Earth orbit is also increasing. To 
date, there are more than 600 thousand objects of space debris 
larger than 1 cm in the near-Earth space [1]. 
Unfortunately, there are no effective measures to eliminate 
and protect spacecraft from space debris. However, objects of 
non-functioning satellites and their fragments in low orbit can 
serve as a repeater of the signal of ground-based electronic 
means.
II. A
NALYSIS OF THE DISTRIBUTION OF SPACE OBJECTS IN 
NEAR
-
EARTH ORBITS
Reflecting objects of electromagnetic waves emitted by the 
transmitter are artificial space objects in near-Earth orbit that 
are capable of scattering or directionally reflecting 
electromagnetic radiation of the operating frequency range of 
the communication line.
65 years have passed since the launch of the first spacecraft. 
More than 7500 space objects have been successfully launched 
in the world during this time. 
Currently, the largest database of space objects contains a 
catalog of American NORAD services. The NORAD catalog 
contains the following information: NORAD Number, 
COSPAR Number, Name, Source, Period, Inclination (in 
degrees), Apogee (in km), Perigee (in km), Eccentricity, etc. 

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About 6% of tracked objects are active. About 22% of the 
facilities have ceased functioning, 17% are spent upper stages 
and upper stages of launch vehicles, and about 55% are waste, 
technological elements accompanying launches, and fragments 
of explosions and fragmentation. 
The Union of Concerned Scientists database consists of the 
following data for active satellites: satellite name, country of 
operator/owner, operator/owner, users, destination, orbit class, 
type of orbit, longitude of the geostationary orbit (in degrees), 
perigee (km), apogee (km), eccentricity, inclination (in 
degrees), period (in minutes), launch mass (kg), dry mass (kg), 
power (Watts), launch date, expected service life, contractor 
(designer), contractor's country, launch pad, launch vehicle, 
COSPAR number, NORAD number, etc.
According to the American non–governmental organization 
Union of Concerned Scientists, among 4,852 active satellites in 
Earth orbit, 2,944 satellites for various purposes belong to the 
United States, 169 – to Russia, 499 - to China, 1,240 – to the 
rest of the world. 
The distribution of active spacecraft in near–Earth space as 
of December 12, 2021, was as follows: the number of satellites 
in low–Earth orbit (LEO), with altitudes from 160 km to 2000 
km above the Earth's surface - 4,078, medium-orbital (MEO) 
satellites, from 2000 km to 35786 km - 141, geostationary 
(GEO) satellites, the altitude of about 35786 km is 574, the 
satellite in an elliptical orbit is 59. 
To analyze the space objects listed in the NORAD database, 
it is necessary to determine the height of the large semi-axis, 
which determines the average distance from the center of the 
Earth. 
By the distribution of space objects by height, it can be 
found out that the most clogged areas of orbits around the Earth, 
which are most often used for spacecraft operation. These are 
Low Earth Orbit (LEO), Medium Earth orbit (MEO), 
geostationary orbit (GEO). Thus, 90% of near-Earth orbit space 
objects are located at an altitude of up to 2500 km. The largest 
number of low-Earth orbit space objects are located at 3 base 
altitudes: 300 km, 800 km, 1500 km. 
Fig. 1. Distribution of space objects by inclination angle 
 
The orientation of the orbital plane in outer space is 
determined by the angle of inclination. The inclination of the 
orbit of a celestial body. According to the results of the analysis 
of the NORAD catalog, it was found that the inclination angle 
of 82.2% of space objects in the range of values from 50° to 
100° (Fig.1). 
One of the 6 Kepler elements of the orbit is the eccentricity, 
which determines the shape of the orbit. Depending on the 
magnitude of the eccentricity e, the orbit has the shape of a 
circle (e=0), an ellipse (01). Analysis 
of the NORAD database showed that the eccentricity of 92.4% 
of space objects in the range of values from 0 to 0.1. 
The reflectivity of space objects is determined by the 
effective scattering area (ESA). ESA is the area σ of some 
fictitious flat surface located normally to the direction of the 
incident plane wave and is an ideal and isotropic re–emitter, 
which, when placed at the point of the object, creates the same 
power flux density at the antenna of the radio-electronic means 
(REM) as the real object. According to the results of the 
analysis of the Space Track catalog [3], it was revealed that the 
ESA of more than 33 thousand space objects is less than 0.1 m
2
, 
the ESA of about 6,135 space objects is between 0.1 m
2
and 1 
m
2
, the ESA of 12,500 space objects is more than 1 m
2
. 
Analysis of the distribution of artificial space objects in 
near-Earth orbits, given in the NORAD catalog, shows that 
more than 35,000 space objects, whose dimensions exceed 10 
cm, are located at an altitude of up to 2500 km from the Earth's 
surface. As reflectors of electromagnetic waves, it is advisable 
to use space objects at an altitude of 100 km, the number of 
which is about 7000. The values of the range of reflecting 
objects can be used 300, 800 and 1500 km as the heights with 
the largest accumulation of objects. Since most space objects 
are in orbits with a high inclination from 50° to 100°, the planes 
of which intersect, the average relative speed of their mutual 
passage is about 10 km/s. 
According to the results of the analysis of the NORAD and 
Space Track catalogs and the calculations carried out, it was 
determined that at any given time at least 251 space objects fly 
over the territory of the Republic of Kazakhstan at an altitude 
of up to 1500 km. At the same time, more than 60 space objects 
have an ESA of more than 1 m
2 
and of these, more than 30 space 
objects are located at an altitude of about 300 km. These space 
objects will be used as reflecting radiation objects in the 
communication system. 
III. A
NALYSIS OF THE POSSIBILITIES OF USING REFLECTED 
RADIATION OF GROUND
-
BASED RADIO
-
ELECTRONIC MEANS 
FROM LOW
-
ORBIT EARTH SATELLITES
In world practice, there are several projects in the 
organization of space radio communications using space 
objects as passive communication repeaters. Early analogues of 
the proposed passive radio communication system are 
American projects of the 60s, such as the Echo program, the 
Westford program and passive radar. 
Echo-1 (1960-1968) was developed for research in the use 
of satellite space repeaters. Due to its considerable size and 
large windage, it was quickly slowed down in the upper layers 
of the Earth's atmosphere. Echo-2 (1964-1969) was used in the 
joint research program on satellite communications of the 
USSR and the USA.
Project West Ford is an experiment carried out in 1961-
1963 by the Lincoln Laboratory of the Massachusetts Institute 
of Technology commissioned by the US Armed Forces. The 
belt of needles is an artificial space formation created in near–

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Earth orbit from many short pieces of thin metal wire thrown 
out of the container of an artificial Earth satellite. 
The main application is to serve as a passive repeater with 
non—directional scattering. Two belts of needles at an altitude 
of about 4000 km, in the equatorial and polar planes, provide 
communication between any ground points. Each of the needles 
was a dipole micro antenna and had 1.78 cm in length and 25.4 
microns (1961 launch) and 17.8 microns (1963 launch) in 
diameter. The needles were placed in near-Earth orbit at an 
altitude between 3,500 and 3,800 kilometers. The first radio 
communication session via an artificial copper cloud took place 
on the fourth day after the launch — between the transmitting 
antenna installed in California and the receiving antenna in 
Massachusetts. 
Spaced radio measuring systems are spaced transmitting 
and receiving devices. The main elements of the system are the 
transmitter subsystem, the receiver subsystem, and the 
observed area of space. 
Taking into account the previous experiences of foreign 
countries, it is proposed to modernize the organization of the 
space communication system using passive communication 
repeaters, which currently are a large amount of space debris in 
near-Earth space. The proposed space communication system 
will be built based on advanced computing and electronic 
digital technology, modern methods of encoding, modulating, 
and processing information will be used. Countries with a large 
territory, such as Kazakhstan, Russia, and China, do not need 
expensive communications throughout the country, low-speed 
communication is allowed in a number of tasks. 
IV. 
A
NALYSIS OF THE REFLECTIVITY OF SPASE OBJECTS
The primary radio wave induces conduction currents (in a 
conductor) or displacement currents (in a dielectric) on the 
surface of objects. These currents are a source of secondary 
radiation in different directions, i.e., radio waves are scattered. 
For a limited number of bodies of a relatively simple shape (a 
half-wave vibrator, a ball, a metal sheet, etc.), an 
electrodynamic calculation of the secondary radiation field is 
possible. However, most real space objects have a more 
complex shape. It is advisable to describe their secondary 
radiation statistically. 
Complex objects can be divided into concentrated and 
distributed. Concentrated objects include objects whose 
dimensions are noticeably smaller than the size of the allowed 
volume of the REM. Examples of such objects are aircraft, 
spacecraft and ships at long distances from the REM. Note that 
concentrated objects, in turn, can be divided into single and 
group objects, consisting of a number of independent single 
objects (for example, a group of spacecrafts within one allowed 
volume). Single concentrated objects will be called point 
objects. Distributed objects include the earth and water surface 
(surface objects), clouds, rain, snow, fog (volumetric objects), 
for which the specified ratio of dimensions and resolution 
elements is not met. They can occupy several allowed volumes. 
The reflective properties of objects depend on its size 
(usually there is a strong dependence on the projection area of 
the body on a plane perpendicular to the direction of the REM), 
the configuration, the surface material, the wavelength of the 
REM, its polarization, the direction of irradiation. 
Effective reflecting area of objects (ERA)—this is the area 
σ
о
of some fictitious flat surface located normally to the 
direction of the incident plane wave and being an ideal and 
isotropic re-emitter, which, when placed at the point of the 
object, creates the same power flux density at the REM antenna 
as the real object. a common expression for ERA: 
𝜎
о
= 4𝜋𝐷
2
(
𝐸
р
2
𝐸
о
2
).
(1.1) 
The lobe scattering diagram (SD) of the shadow contour can 
be interpreted as the radiation pattern of an equivalent flat 
antenna (Fig.2) oriented normally to the beam axis of the 
transmitting antenna. The maximum of the main lobe of the 
shadow field is oriented exactly in the direction of propagation 
of the plane incident wave emitted by the transmitting antenna.