RU2583450C1 - Method of locating ground source of radio-frequency of satellite communication system - Google Patents

Abstract

FIELD: radio engineering.

SUBSTANCE: invention relates to radio engineering and can be used for determining coordinates of radio-frequency source (RFS) of ground satellite communication system (SCS) from flying lifting device (FLD). Said result is achieved by measuring device arranged on FLD to spatial search of ground SCS RFS signal at given height h, moving over free path stores coordinates of N points (N ≥ 5) of proper location detection moments (losses) of ground SCS RFS signal. At that, using coordinates of points ellipsoid horizontal cross-section area of electromagnetic availability is restored, representing in space cone with top in point of arrangement of RFS. Using values of parameters of section (coordinates of centre of semi-axes of large and small dimensions, turning angle of ellipse) and height h azimuth θ and elevation γ direction on RFS are calculated, after which coordinates of ground SCS RFS are determined.

EFFECT: technical result is simplification of equipment due to determination of coordinates of ground SCS RFS by one measuring device.

1 cl, 3 dwg

Description

The invention relates to the field of radio engineering and can be used to determine the location of a ground-based source of radio emission (IRI) from a satellite communications system (CCC) with a flight lifting device (LPS).

There are known systems for determining the coordinates of IRI [1, 2], based on measuring the parameters of radio emissions at several points in space by scanning radio receivers and converted into a system of equations of circles of equal relations, while at least four stationary posts located on more than one straight line are used to measure the parameters of radio emissions , one of which is taken as the base, providing it with additional special software and connecting with the rest of the posts with communication lines. All posts carry out quasi-synchronous scanning at given fixed frequencies.

The indicated systems for determining the coordinates of Iran have a number of significant drawbacks:

- the need to place at least four stationary posts;

- the need for complex tuning of the subsystems for synchronizing peripheral posts for quasi-synchronous frequency scanning;

- the need to use the communication subsystem between peripheral posts;

- the inability to determine the location of ground-based sources of radio emissions from satellite communication systems due to the lack of electromagnetic accessibility to the indicated IRI.

There is also a known method for determining the coordinates of the IRI [3], designed to determine the location of the IRI from a flight-lifting means (LPS) using the goniometer-distance measuring method and based on determining the orientation of the antenna array of the direction finder in three planes while measuring spatial parameters (azimuth and elevation angle) through angular parameters: roll, pitch and heading angle.

The specified system for determining the coordinates of the IRI has a number of significant drawbacks:

- the technical complexity of direction finding systems (using a two-channel interferometer, additional computers);

- the need to place additional angular orientation devices;

- high requirements for precision manufacturing of antenna systems;

- heavy weight and dimensions of the equipment used.

There is also a method of determining the coordinates of the IRI [4], based on the reception of signals from radio sources moving in space by a meter that sequentially determines the signal level (at least four measurements), and the construction of circular position lines. IRI coordinates are defined as the intersection point of the received circular position lines.

The specified system for determining the coordinates of the IRI has a number of significant drawbacks:

- obtaining sufficiently large errors in determining the coordinates of the IRI when crossing tangent circular lines of position at sharp angles (with a bad geometric factor);

- the inability to determine the location of ground-based sources of radio emissions from satellite communication systems due to the lack of electromagnetic accessibility to the indicated IRI.

The closest in technical essence to the claimed method is the "Method for determining the location of the source of radio emission" [5], based on measuring the field strength on the ground by a device moving along a free trajectory and determining from the received data the vector of the electromagnetic field gradient from the investigated IRI at various points on terrain.

The main disadvantage of the prototype is the mandatory presence of a circular radiation pattern of the antenna element of the IRI, since to calculate the coordinates of the source it is necessary to determine pairs of points with the same magnitude of the electromagnetic field, with which the intersection of the middle perpendiculars of the segments constructed at the indicated points is calculated. The second significant drawback of this method is the receipt of large errors in determining the coordinates of the IRI when using this method on very rough terrain due to the multipath effect.

The method is illustrated by illustrations, which represent:

FIG. 1 is a diagram of the flight path of a flight lifting means with a meter;

FIG. 2 - points of space at the moments of detection / signal loss of the investigated IRI;

FIG. 3 - line position of the positioning system IRI CCC.

The proposed method differs from the prototype in that it allows, using the energy detector located on the LPS, to determine the coordinates of the IRI of ground-based CCC stations with any direction of the conical radiation pattern characteristic of antenna elements of ground-based CCC. The use of the mathematical apparatus indicated in the prototype is possible only in the case of a vertical direction of the conical radiation pattern. Thus, the claimed method meets the criteria of the invention of "novelty."

Comparison of the proposed method with other similar methods shows the need for either the presence of distributed processing posts with a synchronization subsystem, or the use of complex antenna systems and / or additional equipment with angular orientation. However, the use of an energy detector when restoring the horizontal section of the radiation pattern of a ground-based IRI allows us to conclude that the proposed method meets the criterion of "significant differences".

The proposed method for determining the location of the source of radio emission is as follows. Let the ground-based IRI SSS be stationary and emit a radio signal in the direction of the satellite, which is in a geostationary orbit, for a time t≥t _ism sufficient for measurements. The measuring device, which is an IRI signal detector, located on a flight-lifting means, moving along a free trajectory at a given height h in a plane parallel to the Earth’s surface, performs a spatial search for the signal of the ground IRI CCC (Fig. 1). At the moments of detection / loss of the signal of the investigated IRI, the measuring device remembers the coordinates of N points of its own location, which, subsequently, calculate the direction and determine the coordinates of the ground IRI CCC.

Radiation from ground-based IRI SSS forms in space a zone of electromagnetic accessibility in the form of a cone with a vertex at the point of placement of the IRI. The axis of the cone is the line between the IRI and the satellite, the angle of inclination β of which relative to the Earth’s surface depends on the relative position of the satellite in orbit and the IRI on the ground. The angle of the cone solution is the angle α, corresponding to the width of the radiation pattern of the IRI antenna system.

The section of a cone by a plane parallel to the Earth’s surface is an ellipse or, in a particular case, a circle (for β = π / 2). These figures are second-order curves, the type of lines of which and their position are uniquely determined by five points, if no four of them lie on one straight line. Therefore, to determine the ellipse, the measuring device must remember the coordinates of N≥5 points of its own location at the moments of detection / loss of the signal of the investigated IRI (Fig. 2).

The canonical equation of an ellipse in a Cartesian coordinate system has the form

where X _n = x _n cosθ + y _n sinθ;

Y _n = -x _n sinγ + y _n cosγ;

x _n , y _n - coordinates of the detection / loss points of the IRI signal;

x ₀ , y ₀ - coordinates of the center of the ellipse;

a , b are the major and minor axes of the ellipse, respectively;

θ is the angle of rotation of the semiaxis a of the ellipse relative to the abscissa axis.

Using the coordinates of N points x _n , y _n, by solving a system of five nonlinear equations (1), find x ₀ , y ₀ , a , b, and also the angle θ that determines the azimuthal direction to the IRI from the center of the ellipse. The ambiguity of determining θ is eliminated by taking into account the fact that the satellite is geostationary, therefore, θ is opposite to the direction to the equator (Fig. 3).

The direction of direction in the IRI γ is calculated in accordance with the expressions (2) ... (5).

By the sine theorem

Where

$$\sin \left(\beta -\frac{\alpha }{2}\right)=\frac{h}{L};$$

$$d=\frac{h}{\tan \gamma }.$$

By the cosine theorem

$$\tan \frac{\mathrm{<figure-callout\; id="2"\; label="\alpha "\; filenames="00000013.png,00000014.png"\; state="\{\{state\}\}">\alpha </figure-callout>}}{2}=\frac{b}{M},\left(\text{four}\right)$$

Where

.Substituting K, L and M in (2), (3) and (4), we find sinα, cosα and $$\mathrm{<figure-callout\; id="2"\; label="tan\; \alpha "\; filenames="00000013.png,00000014.png"\; state="\{\{state\}\}">tan\; </figure-callout>}\raisebox{1ex}{$\alpha $}\!\left/ \!\raisebox{-1ex}{$$}\right.\raisebox{1ex}{$$}\!\left/ \!\raisebox{-1ex}{$2$}\right.$$

.

в (5), находят угломестное направление на ИРИ γ из центра эллипса. Координаты наземного ИРИ ССС определяют как точку пересечения прямой, направленной на источник под углами θ и γ, с поверхностью Земли. Двузначность определения координат ИРИ ССС устраняется учетом того факта, что ИСЗ является геостационарным, следовательно, азимутальное направление на ИРИ 9 противоположно направлению на экватор.Substituting sinα, cosα and $$\mathrm{<figure-callout\; id="2"\; label="tan\; \alpha "\; filenames="00000013.png,00000014.png"\; state="\{\{state\}\}">tan\; </figure-callout>}\raisebox{1ex}{$\alpha $}\!\left/ \!\raisebox{-1ex}{$$}\right.\raisebox{1ex}{$$}\!\left/ \!\raisebox{-1ex}{$2$}\right.$$

in (5), they find the elevation direction to the IRI γ from the center of the ellipse. The coordinates of the ground IRI CCC are defined as the point of intersection of a straight line directed to the source at angles θ and γ with the Earth's surface. The ambiguity in determining the coordinates of the IRI SSS is eliminated by taking into account the fact that the satellite is geostationary, therefore, the azimuthal direction to IRI 9 is opposite to the direction to the equator.

Bibliography

1. Loginov Yu.I. et al. Patent RU No. 2423721, published July 10, 2011.

2. Loginov Yu.I. et al. Patent RU No. 2430385, published September 27, 2011.

3. Ivanov, Yu.I. et al. Patent RU No. 2419106, published May 20, 2011.

4. Balyukov V.M. et al. Patent RU No. 2306579, published September 20, 2007.

5. Alexandrov V.G. et al. Patent RU No. 2319169, published March 10, 2008.

USED SOURCES

1. Loginov Yu.I. et al. Patent RU No. 2423721, published July 10, 2011.

2. Loginov Yu.I. et al. Patent RU No. 2430385, published September 27, 2011.

3. Ivanov, Yu.I. et al. Patent RU No. 2419106, published May 20, 2011.

4. Balyukov V.M. et al. Patent RU No. 2306579, published September 20, 2007.

5. Alexandrov V.G. et al. Patent RU No. 2319169, published March 10, 2008.

Claims (1)

A method for determining the location of a ground-based radio emission source (IRI) of a satellite communications system (CCC), which consists in performing a spatial search for the signal of the investigated IRI by a measuring device moving along a free path, storing the coordinates of the measuring device’s own location at certain N points in space, and calculating the direction from the points on IRI SSS and determine its coordinates as the point of intersection of a straight line with the Earth’s surface, characterized in that the measuring device The property, which is an IRI signal detector, located on a flight-and-lift vehicle, moves in space along a free trajectory at a given height h in a plane parallel to the Earth’s surface, outside the electromagnetic accessibility zone (EMD) of the ground IRI CCC, at the moment of detection / loss of the signal under study IRI measuring device remembers the coordinates of N points (N≥5) of its own location, the coordinates of N points restore an elliptical horizontal section of the EMD zone, which is a cone with a vertical different at the location of the IRI, the azimuthal θ and elevation γ direction to the IRI from the center of the section is calculated from the parameters of the cross-section (the coordinates of the center, the dimensions of the major and minor axes, the angle of rotation of the ellipse) and the height h, and then the coordinates of the ground-based IRI CCC are determined as the intersection point direct directed to the source, with the surface of the Earth.

Images