RU2368076C2 - Method for aiming of retransmitter antennas - Google Patents

Abstract

FIELD: physics, radio engineering.

SUBSTANCE: invention is related to communication systems and is intended for retransmission of radio television signals. Substance of stated method consists in performance of additional operations in process of transmitting and receiving antennas aiming, which are carried out in mode of initial aiming of retransmitter and in mode of information transfer, with application of additional angle detector and possibility for compensation of retransmitter base shifts.

EFFECT: improved accuracy of retransmitter transmitting antenna aiming, simplification of equipment in operation.

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Description

The invention relates to communication systems and can be used to expand the service area in areas where there is no or unstable reception of a microwave television signal.

The reason for this is the terrain: the direct passage of the signal from the signal source to the receiving point is impeded by the presence of a hill or mountain barrier, or the receiving point is located in a hollow. In such cases, special microwave communication lines and repeaters are used. The source of the radio television signal may be a ground source or a spacecraft (SC).

Known methods for pointing antennas of spacecraft that use the technical means of spacecraft orientation and navigation systems (Bartenev V.A., Bolotov G.V., Bykov V.L. et al. Edited by Kantor L.A. Satellite communication and broadcasting. - M .: Radio and communications, 1997, p.334-349). In this case, the accuracy of pointing the antenna to a given point on the Earth's surface is determined by errors in the angular stabilization of the spacecraft, errors in the installation of the antenna on the landing surfaces of the spacecraft relative to the coordinate system associated with the spacecraft, errors in the spacecraft coordinate system relative to the coordinate system associated with the Earth, and errors in the manufacture of the antenna. The accuracy of pointing such antennas is low (at the level of 30-60 arc minutes).

The disadvantages of this method of pointing the antennas are relatively low accuracy, due primarily to the technical characteristics of the spacecraft, as well as the lack of a sufficiently accurate autonomous antenna pointing system.

In terrestrial satellite communication stations, which are usually transceiver radios with one common antenna (for receiving and transmitting), for pointing the antenna, guidance methods are used in which the program guidance mode is set to a given point in space, as well as the exact guidance mode for the received signal, into which they are transferred by means of signal search and capture (Pokras AM, Somov A.M., Tsurikov G.G. Antennas for satellite earth stations. - M.: Radio and communications, 1985, p. 35-76).

In the accurate guidance mode on the received signal, various guidance methods on the received signal, extreme guidance method, monopulse method, etc. can be used.

The disadvantage of these methods is the difficulty in implementing accurate programmed guidance of the antenna, which is associated with the need to use sufficiently complex accurate measuring tools.

The prototype of the invention is a method of pointing an antenna of a satellite communications station containing a parabolic mirror antenna with a microwave unit and azimuth and elevation axis blocks, an antenna pointing unit, a computing device equipped with programs, including antenna pointing programs (Frolov O.P. Antennas for satellite earth stations Communications. - M.: Radio and Communications, 2000, p. 260-265).

In this method, the antenna is programmed to be guided by elevation and azimuth to a given point in space, as well as the antenna is accurately guided to a signal source using auto tracking (i.e., working on a received signal) implemented using the extreme guidance method. The antenna’s exact guidance mode is carried out by switching from the program guidance mode using the search and capture of the signal. Precise pointing of the antenna to the signal source is also carried out with constant programmatic pointing of the antenna by the correct elevation angle and azimuth, with the automatic tracking being turned on periodically to clarify the elevation angle and azimuth of the signal source.

Software guidance of the antenna in elevation and azimuth is carried out by turning the antenna to the angles calculated in the computing device from the basic measuring planes:

- horizon plane - for elevation;

- meridian planes - for azimuth.

The disadvantage of this method of pointing the antenna is the relatively low accuracy of the software guidance. This is primarily due to the error in determining the meridian.

For highly directional antennas (beamwidth less than 30-40 arc minutes), the task of accurately programmatically guiding the transmitting antenna to the subscriber station, as well as maintaining this direction during operation, is one of the most difficult. In these devices, due to the lack of a receiving channel, signal feedback cannot be used to increase the accuracy of antenna pointing, as is done in transceiver stations.

For stationary repeaters placed on a rigid base, it is sufficient to solve the problem of the exact initial pointing of the transmitting antenna, which can be considered as a one-time operation using high-precision and expensive additional equipment that is not part of the repeater.

The deviation of the base of the repeater from the horizontal plane (non-horizontal error) can be determined using a local vertical device, for example, a pendulum type.

Astronomical measuring instruments or a high-precision radio compass can be used to determine the meridian.

This task is more complicated for mobile repeaters placed, for example, in a car body or on a temporary platform.

In this case, the errors of the initial pointing of the transmitting antenna to the subscriber station are supplemented by angular errors due to seasonal ground movements. These errors can reach 30-60 arc minutes. In addition, daily angular errors are possible with non-rigid, moisture-saturated soil. In these repeaters, the local vertical and the meridian must be constantly determined. Therefore, built-in measuring equipment should be used.

The deviation of the azimuthal axis of the repeater from the local vertical in this case can be determined with the required accuracy using angle sensors, for example, a pendulum type.

A more difficult task is the accurate determination of the meridian. Astro vehicles with the greatest accuracy cannot be used because of the need to ensure constant all-weather operation. The compass with acceptable dimensions (measuring base 4-6 meters) has an accuracy (at 3σ level) of 10-15 arc minutes. This is not enough for the analyzed repeaters.

An object of the invention is to increase the accuracy of pointing the transmitting antenna of the repeater, as well as eliminating the use of additional equipment for pointing the transmitting antenna during operation and, accordingly, simplifying and reducing the cost of the equipment.

This problem is solved in such a way that in the method of pointing the antennas of the repeater, the receiving antenna of the repeater is guided to the signal source, and when pointing, the receiving antenna is turned in azimuth and elevation to capture the signal, and then the target antenna is precisely guided in azimuth and elevation using software guidance and auto-tracking operations with correction for the received signal, and also programmatically guide the transmitting antenna of the repeater to the subscriber station at the calculated azimuth and All places, in this case, the initial pointing mode of the repeater is entered, in this mode, before pointing the receiving antenna to the signal source, it is set in azimuth to an angle that differs ninety degrees from the direction to the signal source, and the base angle of the repeater relative to the horizon is measured using an angle sensor installed on the azimuthal axis of the receiving antenna, then the receiving antenna is rotated first in elevation to the calculated angle of the signal source, taking into account the measured base angle p transmitter, and then turn in azimuth until the signal is captured, after which, in the mode of accurately pointing the receiving antenna to the signal source after the auto-tracking operation, the azimuth and elevation angle of the signal source are specified, and in this mode, the angle of the repeater’s base relative to the horizon plane is also measured the angles found in the exact guidance of the receiving antenna are input into the computing device and used as initial values during the subsequent operation of correcting the program azimuth and angle places of the subscriber station in the mode of transmitting information of the repeater, while the azimuth of the signal source and the base angle of the repeater are also used to find the program azimuth of the subscriber station in the initial pointing mode of the repeater, after which the receiving antenna is installed in azimuth at an angle different from the azimuth of the subscriber station by ninety degrees, and then the receiving antenna is installed at an angle corresponding to the azimuth of the subscriber station, in both positions is measured using the angle sensor y ol of the base of the repeater relative to the horizon plane, the measurement data is used to determine the corrections of the azimuth and elevation angle of the subscriber station, after which the receiving antenna is azimuthally directed to the signal source and programmed in accurate guidance, and the transmitting antenna is guided by the calculated azimuth and elevation taking into account the corrections found to the subscriber station, then in the transmission mode of the relay information cyclically after each operation of the auto-tracking of the receiving antenna at The measuring device introduces the current values of three parameters: the azimuth and elevation angle of the receiving antenna, as well as the angle of rotation of the receiving antenna, determined using the angle sensor, then find the differences between the current and initial values of these parameters, determine the departures of the base of the repeater based on the measurement results of these three parameters and find corrections to the program values of the azimuth and elevation angle of the subscriber station, the corrections found for both angles are compared with the permissible deviations, after which if one or both amendments exceeds the permissible deviation, the program value of the angle of the subscriber station is corrected, the deviation of which from the program value exceeds the permissible value; at the same time, for the given angle of the subscriber station, the initial values of the base angle of the repeater are corrected, as well as the initial value of the correction to the program value this angle, then carry out the software guidance of the transmitting antenna to the subscriber station at the corrected angles.

The method is implemented in the repeater through the use of an additional angle sensor mounted on the azimuthal axis of the receiving antenna, as well as additional operations when pointing the transmitting and receiving antennas. These operations are carried out in the initial guidance mode of the repeater and in the mode of information transfer.

As an example, we consider a repeater in which both the receiving and transmitting antennas are highly directional parabolic reflector antennas with a beam pattern width Д Д Н equal to 30 angular minutes.

For frequencies from 6 to 12 GHz, the diameter of such an antenna should be from 7 to 3.5 meters.

The accuracy of pointing the antenna with a power loss of 0.5 dB is considered sufficiently high, which corresponds to a pointing error of the antenna under consideration of ± 6 arc minutes, i.e. ± 0.2 φDN.

The method is illustrated in FIGS. 1-4, in which: FIG. 1 is a functional diagram of a repeater, FIG. 2 is a flowchart of an initial guidance mode of a receiving and transmitting antenna of a repeater, FIG. 3a, b, c, d, d - the error of pointing the antenna in elevation and azimuth due to its rotation around the optical axis, Fig. 4 is a block diagram of a program for correcting azimuth and elevation of a subscriber station.

The repeater shown in Fig. 1 comprises a receiving antenna 1 on which a microwave unit 2 of the receiving antenna is mounted connected to a microwave unit 4 of the transmitting antenna located on the transmitting antenna 3. The microwave unit 2 and the microwave unit 4 are designed to amplify, filter, and convert the frequency of the relayed microwave signal. The second output of the microwave unit 2 of the receiving antenna is connected to the block 5 of the guidance of the receiving antenna, designed to convert the microwave signal into a signal used for precise guidance of the receiving antenna 1. For control along the azimuth axis 6 of the receiving antenna, the relay includes a block 7 of the azimuthal axis of the receiving antenna, and for control along the elevation axis 8 of the receiving antenna, a block 9 of the elevation axis of the receiving antenna. An angle sensor 10, for example, of a pendulum type, is used to measure the accuracy of the relay exhibit relative to the horizon plane on the azimuthal axis of the receiving antenna.

For control along the azimuthal axis 11 of the transmitting antenna, the repeater comprises a block 12 of the azimuthal axis of the transmitting antenna, and for control along the elevation axis 13 of the transmitting antenna, a block 14 for the elevation axis of the transmitting antenna.

The composition of blocks 7 and 9 of the receiving antenna and blocks 12 and 14 of the transmitting antenna include angle sensors with signal processing devices, as well as drives that provide axis rotations.

The repeater also includes a computing device 15, designed to control the receiving antenna 1 and the transmitting antenna 3 and connected to the block 5, the angle sensor 10, and also with blocks 7, 9, 12 and 14.

The receiving antenna 1 of the relay is intended to amplify the received radio television signal 16 coming from the signal source, and the transmitting antenna 3 is to amplify the radiated television and radio signal 17 coming from the relay to the subscriber station.

Figure 2 shows the operation:

18 - bringing the receiving and transmitting antennas to their initial position in azimuth and elevation and stabilizing them in this position;

19 - installation of the receiving antenna in azimuth at an angle that differs by 90 degrees from the direction to the signal source, measuring and introducing ΔГП1 into the computing device;

20 - a turn of the receiving antenna to the position (Az = Az _ik , UM = UM _pi );

21 - search for a signal source;

22 - precise pointing of the receiving antenna to the signal source;

23 - measurement and introduction to the computing device ΔГП2;

24 - installation of the receiving antenna in azimuth at an angle that differs by 90 degrees from the direction to the subscriber station, measuring and introducing ΔГП3 into the computing device;

25 - turn of the receiving antenna in azimuth to the subscriber station, measuring and introducing ΔГП4 into the computing device;

26 - turn the receiving antenna in azimuth to the position (Az = Az _pi , UM = UM _pi ) and accurately pointing the receiving antenna to the signal source;

27 - pointing the transmitting antenna in the corrected azimuth and elevation to the subscriber station.

Notation used here:

Az - azimuth;

UM - elevation;

ΔГП1, ΔГП2, ΔГП3, ΔГП4 - error of the relay relative to the horizon plane (error of non-horizontalness);

Az _IR - the initial azimuth of the signal source, determined using a compass;

UM _pi - program angle of the signal source;

Az _pi is the program azimuth of the signal source.

Figure 2 shows the well-known regular operations of pointing the receiving and transmitting antennas of the repeater, as well as new additional operations, the use of which made it possible to obtain the specified technical result.

The flowchart reflects the sequence of operations and their relationship.

The mutual reference of the azimuthal and elevation systems of both antennas 1 and 3 (Fig. 1) is made in the manufacture of the repeater. The error in installing the repeater on the landing plane relative to the horizontal plane is measured and compensated by using the angle sensor 10. The usually used initial exhibition of the base of the repeater parallel to the horizontal plane (leveling) with the help of gaskets and washers is not practical in this case. This is due to a violation of leveling due to soil drift. The initial binding of the azimuthal repeater system to the meridian is carried out using a simple relatively rough magnetic compass or radio compass having an error of 0.5 to 3 degrees. Since the compass is used only during initial guidance, it may not be part of the repeater equipment.

A method of improving the accuracy of pointing the transmitting antenna of the repeater is implemented as follows.

After applying power to the repeater according to the program of computing device 15 (Fig. 1), a regular operation is performed (Fig. 2): 18 - bringing the receiving and transmitting antennas 1 and 3 (Fig. 1) to the initial position in azimuth (Az = 0) and elevation (UM = 0) and their stabilization in this position.

Antennas are controlled using computing device 15 (Fig. 1).

For a programmatic turn in azimuth of the receiving antenna 1 according to the signals of the computing device 15, a drive is used located in the block 7 of the azimuthal axis of the receiving antenna. The turn is made around the azimuth axis 6.

Using a drive located in block 9 of the elevation axis of the receiving antenna, a rotation is performed around the elevation axis 8. Turns of the transmitting antenna 3 are performed using a drive located in block 12 of the azimuthal axis of the transmitting antenna, around the azimuth axis 11, and also a drive located in the block 14 of the elevation axis of the transmitting antenna, around the elevation axis 13.

The turning speed of the antennas 1 and 3 in question is from a few degrees to thirty degrees per second. The stabilization time of antennas 1 and 3 is determined by the dynamic characteristics of the control loop. The minimum required time does not exceed 1 second.

Then, using block 7 and computing device 15, an additional operation 19 (Fig. 2) is carried out, which includes turning the receiving antenna 1 (Fig. 1) in azimuth and setting it to an angle that differs by 90 degrees relative to the direction of the signal source, stabilizing the receiving antenna 1 in this position, as well as measuring and introducing into the computing device 15 the error of non-horizontalness Δ GP1. The measurement is carried out using the angle sensor 10. The sensitivity axis of the angle sensor 10 in the manufacture of the repeater is attached to the coordinate system of the repeater, and to ensure maximum sensitivity it is set perpendicular to the elevation axis and the azimuth axis of the receiving antenna 1.

The measurement of the non-horizontal error of the ΔГП1 repeater makes it possible to simplify the operation of searching for a signal source. In this case, the error of the software guidance of the receiving antenna 1 to the signal source in elevation does not exceed half the width of the antenna pattern. Therefore, a single-line azimuth scan can be used in the search.

In the invention, it is proposed to use the direction of the optical axis of the receiving antenna 1 to the signal source (terrestrial or satellite) as a physically feasible exact azimuthal base direction. In this case, the direction of the meridian, which is used in the guidance program of the transmitting antenna 3, is calculated. The angle ψ _and between the meridian and the direction to the signal source and the angle ψ _с between the meridian and the direction to the subscriber station are found by the known coordinates (latitude and longitude) of the signal source, subscriber station and repeater. If the signal source is the spacecraft, then take the coordinates of the sub-satellite point - the intersection of the Earth's surface and a straight line segment between the center of the Earth and the spacecraft.

When pointing the receiving antenna 1 to the signal source determine the azimuth angle (azimuth) Az _and . The azimuth angle Az _c required for the azimuthal pointing of the transmitting antenna 3 to the subscriber station, is found from the formula

After operation 19 (FIG. 2), regular operation 20 is performed — turn the receiving antenna 1 (FIG. 1) to the position Az = Az _ik , UM = UM _pi and stabilize it in this position. The receiving antenna 1 is controlled by a computing device 15 and blocks 7 and 9.

Azimuth Az = _Azk corresponds to the initial azimuth of the signal source, determined using a compass.

Elevation angle UM = UM _pi corresponds to the program angle of the signal source, which is found from

where UM _ri is the calculated elevation angle of the signal source relative to the horizontal plane, found for a known location of the signal source and repeater.

Then carry out a regular operation (figure 2) 21 - search for the signal source. When searching for a signal source, the movement of the receiving antenna 1 (Fig. 1) is carried out only in azimuth using a computing device 15 and block 7.

The received radio television signal 16 from the signal source is detected using the receiving antenna 1. In the microwave unit 2, the microwave signal is converted: filtering, amplification, frequency change. After conversion, the signal is supplied to the receiving antenna pointing unit 5. Using this signal, the guidance loop of the receiving antenna 1 is realized by the received signal.

The signal capture is fixed using block 5 when the received signal exceeds the level from 0.5 to 0.7 of the maximum signal value.

After capturing the signal, a regular operation is performed (Fig. 2) 22 — precise pointing of the receiving antenna to the signal source in azimuth and elevation using auto tracking, for example, using the well-known extreme guidance method. The time of this operation depends on the required accuracy of guidance and can range from several units to several tens of seconds.

Operation 22 is carried out using a computing device 15 and blocks 5, 7 and 9 (figure 1).

With the exact pointing of the receiving antenna 1 to the signal source using the well-known operation — auto tracking — the program azimuth and elevation angle of the signal source are refined. These specified angles are measured by azimuth and elevation sensors of the angle of the receiving antenna 1 and input into the computing device 15. The adjusted values of these angles are used in the well-known standard operation of accurately pointing the receiving antenna 1 when it is programmed to the signal source before the next auto tracking operation. They are also used as initial values during a new operation - correction of program azimuth and elevation of a subscriber station in the mode of information transfer.

In the same new operation, the results of measurements of the angle sensor 10 are used as the initial value, which are input to the computing device 15 simultaneously with the specified azimuth and elevation angles of the receiving antenna 1. These measurements are made in the mode of accurately pointing the receiving antenna 1 to the signal source when additional operation (figure 2) 23 - measurement using the sensor 10 (figure 1) of the angle and the introduction into the computing device 15 of the horizontal error Δ GP2.

Figure 3a shows an orthogonal 3-axis coordinate system in which the X0Z plane coincides with the horizontal plane, the signal source (IC) is located in the X0Y plane, the subscriber station (C _T A) is azimuthally rotated relative to the signal source at an angle ε. The angles UM _ri and UM _pc are the calculated elevation angles of the signal source and subscriber station relative to the horizontal plane. The angles α, β, γ are the base rotation angles, respectively, around the Y, Z, and X axes. The β ₁ and γ ₁ angles are the base rotation angles, respectively, around the Z ₁ and X ₁ axes. The positive direction of the turn is counterclockwise. The error ΔГП1 corresponds to a rotation around the Z axis, ΔГП2 corresponds to the axis X. The error ΔГП2 represents the turning angle (SD) of the receiving antenna 1 around its optical axis relative to the vertical. The non-horizontalness error ΔГП2 of the base of the repeater leads to additional errors in pointing the receiving antenna 1 in azimuth ΔАз (UR) and elevation angle ΔУМ (UR). The receiving antenna 1 must be further rotated at these angles (in azimuth and elevation) in order to ensure accurate guidance to the signal source, taking into account this error of the base of the repeater.

On figb, c, d, d diagrams of occurrence and compensation of the indicated errors of the receiving antenna 1 (Fig. 1) ΔAz (SD) and ΔUM (SD) are shown.

On figb, c, d shows three projections of a conditional sphere with radius R, the center and axes of which coincide with the center and axes of the coordinate system XYZ (figa).

On these projections are depicted:

UM - elevation angle of the receiving antenna 1 (figure 1);

UR - angle of the base of the repeater around the X axis (for clarity, this angle is shown more than the real value, which does not exceed 30-60 angular minutes);

S ₁ is a section of a sphere perpendicular to the X axis;

S ₂ and S ₃ are sections of a sphere perpendicular to the Y axis;

S ₄ is a section of a sphere perpendicular to the axis Y ₁ , which is rotated in the XOY plane relative to the Y axis by the angle UR;

RsinUM - section radius S ₁ ;

RcosUM - the radius of the sections S ₂ and S ₄ ;

01 - the segment corresponding to the direction of the optical axis of the receiving antenna 1 to the signal source with SD = 0;

02 - the segment corresponding to the direction of the optical axis of the receiving antenna 1 in the presence of error SD;

a - a segment connecting points 1 and 2 and corresponding to the displacement of the optical axis of the receiving antenna 1 when the base of the repeater is rotated by an angle of SD;

b is the length of the segment 23 in section S ₁ corresponding to the displacement of the optical axis of the receiving antenna 1 in azimuth when the base of the repeater is rotated through the angle of the SD;

C is the length of the segment 13 in section S ₁ corresponding to the displacement of the optical axis of the receiving antenna 1 in elevation when the base of the repeater is rotated through the angle of the SD.

On fig.3d shows the points 1, 2, 3 of the displacement of the optical axis of the receiving antenna 1 (Fig.1) in section S ₁ when the repeater is rotated through the angle of the SD.

From a right triangle 032 (fig. 3d) find b - the length of the segment 23

In the cross section S ₃ (FIGS. 3b and 3d), the radius of the cross section is Rсos [UM-Δ UM (UR)].

From triangle 032 in section S ₃ (Fig. 3d) also determine b - the length of the segment 23

Considering that UR = ΔGP2 and angles ΔGP2, ΔAz (UR), ΔUM (UR) are small (less than 60 arc minutes), replace sin ΔAz (UR) with ΔAz (UR) and sinYP with ΔGP2. Moreover, from expressions (3) and (4), the error in azimuth is found

The error in elevation is found from a right triangle 043 (Fig.3b), in which

The length of the segment 13 is determined from a right triangle 231 (Fig. 3d)

From formulas (3), (6) and (7), taking into account the conditions adopted upon receipt of formula (5), additionally including the replacement of tg (UR / 2) with ΔГП2 / 2, сsΔUM (UR) with 1 and cos [УМ -ΔUM (SD)] on cosUM, find the error in elevation

In order to return the optical axis of the receiving antenna 1 (Fig. 1) from point 2 to point 1 (Fig. 3c), it is necessary to perform an azimuthal rotation of the receiving antenna 1 (Fig. 1) around the axis Y ₁ (in section S ₄ ), as well as a rotation around the corner of the place.

Using the projection of the secant arcs reflecting the motion of the optical axis of the receiving antenna onto the section S ₁ (Fig. 3d), a segment 25 of length d corresponding to the azimuthal turn and a segment 51 of length e corresponding to the rotation along the elevation angle of the receiving antenna 1 are obtained (Fig. 1 )

For small angles ΔAz (UR) (no more than 40 angular minutes) and ΔUM (UR) (no more than 0.4 angular minutes), the error of these transformations (cosine error) is negligible (less than 10 ^-4 ).

Rectangular triangles 231 and 251 (Fig. 3d) are equal, since the angle 321 is equal to the angle 521.

In the triangle 102, the angle 120 is equal to (90 ° -UR / 2), in the triangle 230 the angle 320 is equal to (90 ° -UR), from which the angle 321 is determined - UR / 2.

The angle 025 is straight, so the angle 521 is equal to UR / 2.

Thus, d = b and e = c are obtained.

Therefore, the turning angles of the receiving antenna 1 (Fig. 1) in azimuth and elevation to compensate for the angle of the base of the relay UR relay are found, respectively, from the obtained formulas (5) and (8).

For the most common values of the elevation angle of the signal source from 12 to 35 degrees, the error ΔАз (UR) is from 0.2 ΔГП2 to 0.7 ΔГП2. If, for example, ΔГП2 = 20 arc minutes, then ΔАз (УР) can be from 4 to 14 arc minutes. Since ΔГП2 does not exceed 30-60 arc minutes (0.01-0.02 radians), then, in accordance with formula (8), the error ΔУМ (УР) is 100-200 times less than ΔАз (УР) and may not be taken into account. To evaluate the correction ΔAz (SD) of the receiving antenna 1 (Fig. 1), the elevation angle is found from formula (2) and from formula (5),

The ΔAz (SD) correction found from expression (9) is used in determining the program azimuth of the subscriber station.

Then carry out an additional operation 24 (figure 2) - the receiving antenna 1 (figure 1) is turned in azimuth and set at an angle that differs by 90 degrees from the direction to the subscriber station. The elevation angle of the receiving antenna 1 does not change.

Using the angle sensor 10, the error of the relay ΔГП3 relative to the horizon plane is measured and introduced into the computing device 15. This error is a correction for the elevation of the subscriber station.

After this, an additional operation 25 (Fig. 2) is carried out - the receiving antenna 1 (Fig. 1) is turned in azimuth and installed in the azimuth of the subscriber station, measured using the angle sensor 10 and the accuracy of the DGP4 relay relative to the horizon plane is entered into the computing device 15.

Errors ΔГП3 and ΔГП4 can be determined by calculation from the found values of ΔГП1 and ΔГП2. Direct measurement of ΔГП3 and ΔГП4 allows one to reduce the errors in determining these errors from 2-3 angular minutes to 0.25-0.5 angular minutes by taking into account the bends of the repeater base that occur when the base is attached to landing sites, the height of which may vary. The effect of bending increases with significant sizes of antennas (diameter up to 7 meters) and the base (length up to 8.5-9.5 meters). These operations give the greatest effect when finding the software elevation angle of the subscriber station.

The error ΔГП4 characterizes the rotation of the transmitting antenna 3 around the optical axis relative to the vertical. It leads to additional errors in azimuth and elevation, which are found using formulas (5) and (8) with the replacement of ΔГП2 by ΔГП4. Moreover, this error in elevation, as noted, is small and may not be taken into account.

The software elevation angle of the subscriber station is calculated in the computing device 15 in accordance with the formula

where UM _pc is the estimated elevation angle of the subscriber station relative to the horizontal plane.

The azimuth of the subscriber station, in accordance with the formula (1), is calculated in the computing device 15 by the formula

The value of Az _and , as indicated, is found in the exact guidance of the receiving antenna to the signal source, the correction ΔAz _and (SD) are determined in accordance with formula (9). The correction ΔAz _with (SD) taking into account formulas (5) and (10) is found from the following formula

The elevation angle calculated for the subscriber station UM _s and the azimuth Az _s are entered into the memory of computing device 15 and used to program the transmitting antenna 3 to the subscriber station.

Then carry out a regular operation 26 (Fig. 2) - turn the receiving antenna 1 (Fig. 1) in azimuth to the signal source and provide accurate guidance of the receiving antenna 1. In this case, accurate guidance is implemented as software guidance to the signal source in azimuth and elevation refined as a result of auto tracking conducted during operation 22 (figure 2).

After that, an additional operation 27 (Fig. 2) is carried out - the transmitting antenna 3 (Fig. 1) is directed to the subscriber station in azimuth and elevation, calculated according to formulas (11) and (10), respectively.

The control of the transmitting antenna is carried out in the mode of software guidance to the subscriber station.

The initial guidance operations of the receiving and transmitting antennas 1 and 3 of the repeater are completed and go to the transmission mode of information of the subscriber station from the signal source. In this mode, the receiving antenna 1 is programmed to the signal source with periodic correction according to the received signal (auto tracking operation). In particular, the extreme guidance method, which has become widespread, can be used for correction. Also in this mode, the transmitting antenna 3 is programmed to the subscriber station.

In the invention, for the mode of transmitting information of the relay, they solve the problem of increasing the accuracy of pointing the transmitting antenna 3 to the subscriber station by compensating for the angular errors caused by seasonal and daily soil movements.

The required accuracy of pointing the receiving antenna 1 to the signal source is ensured by using the well-known method - periodic correction of the signal (auto tracking). In this example, the well-known extreme guidance method is used.

Figure 4 shows the block diagram of the program of the new operation - correction of program bearing and elevation of the subscriber station.

This operation includes the measurement and input into the computing device 15 (figure 1) of the following parameters:

Az _in - the initial value of the azimuth of the signal source;

Az and _t - the current value of the azimuth of the signal source;

UM _in - the initial value of the elevation angle of the signal source;

UM and _t is the current value of the elevation angle of the signal source;

γ _n - the initial value of the angle of rotation of the base of the repeater relative to the vertical;

γ _t is the current value of the angle of rotation of the base of the repeater relative to the vertical.

This operation also includes operations performed in the computing device 15, which are shown in FIG. 4, and moving the transmitting antenna 3 (FIG. 1) according to the results of the correction of the program values of the azimuth and elevation angle of the subscriber station.

The first operation to correct the program azimuth and elevation of the subscriber station begins after the second operation of auto tracking with the exact pointing of the receiving antenna 1 to the signal source. This auto tracking operation is the first for the relay information transfer mode.

In the block diagram of the program shown in FIG. 4, as an initial operation (FIG. 4, operation 28), initial values of the angles Az _in , UM _in and γ _n are input into the computing device 15 (FIG. 1). These values were found and entered into the computing device 15 during operations 22 and 23 (figure 2).

The azimuth and elevation angle of the signal source corrected after the auto-tracking, as well as the simultaneously measured results of measurements of the angle sensor 10 (Fig. 1), are input into the computing device 15 as the current values of these parameters (Fig. 4, step 29).

In the computing device 15 (figure 1) find the difference between the current and initial values of these parameters (figure 4, operation 30):

Then, the following operation 31 is carried out - determining the turning angles of the base of the repeater α, β, γ around the axes Y, Z, X and the angles β ₁ , γ ₁ around the axes Z ₁ and X ₁ (Fig. 3a), as well as determining the current program corrections azimuth and elevation of the subscriber station.

The angles of the base of the repeater (current values) for the elapsed time interval between two auto tracking operations are found from the formulas

The angle Δγ _{t is} measured by the angle sensor 10 (Fig. 1).

In accordance with the above analysis, the quantities k ₁ Δγ _t and k ₂ Δγ _{t are} determined from formulas (5) and (8) with the replacement of ΔГП2 by Δγ _t , and the value of k ₂ Δγt is small and may not be taken into account. Formulas (14) transform to the form

The base rotation angles (current values) around the axes Z ₁ and X _{1 are} found from the formulas

Using formulas (15) and (16), the current corrections are determined by azimuth and elevation of the subscriber station:

where the coefficient to _{3 is} found from formula (5)

After that, carry out operation 32 (figure 4) - a comparison of the corrections ΔAz _ct and ΔUM _ct with acceptable values, respectively, ΔAz _sd and ΔUM _sd .

If at both angles the corrections in absolute value are less than the permissible values, then the operation of correcting the program angles of the subscriber station is not carried out (Fig. 4, operation 33 — logical operation AND).

With slow departures of the base of the repeater, the operations of correcting the software angles of the subscriber station can be performed at significant intervals, including a large number of auto tracking operations, which are carried out to compensate for the departures of the spacecraft.

If the correction for one or both angles exceeds the permissible value, then the next operation 34 is carried out — the correction in the computing device 15 (Fig. 1) of the program value of that angle of the subscriber station whose deviation from the program value exceeds the permissible value.

At the same time, operation 35 is performed - the initial values of the angles are corrected, respectively, in the azimuth of the subscriber station (ΔAz _sn , α _n , β _n , Δγ _n ) and the elevation angle of the subscriber station (ΔUM _sn , β _n , Δγ _n ).

In the first operation of correcting the program angles of the subscriber station, the initial values of the angles ΔAz _sn , Δ UM _sn , α _n , β _n , Δγ _n are 0.

In subsequent operations, the initial values of these angles are determined by the results of the previous correction of the program angles of the subscriber station.

Starting from the second operation of the correction of the program angle of the subscriber station (azimuth or elevation angle), instead of formulas (17), formulas are used

The initial values of the corrections in azimuth (ΔAz _sn ) and elevation (ΔUM _sn ) of the subscriber station are found by the formulas

The initial values of the angles α _n and β _{n are} determined using formulas (15), and the angle Δγ _n is determined by the readings of the angle sensor 10 (Fig. 1).

The angles Δα, Δγ _1t and Δβ _1t in formulas (19), taking into account formulas (15) and (16), are determined using the following formulas:

Where

After that, according to the results of the correction of the software angles of the subscriber station, program guidance (moving) of the transmitting antenna 3 to the subscriber station is carried out at corrected angles.

The operation of correcting the software angles of the subscriber station in the transmission mode of the relay information is carried out continuously after the auto tracking operation.

The error in the programmatic guidance of the transmitting antenna 3 of the repeater to the subscriber station in azimuth in the initial guidance mode includes the following main components: the navigation error of pointing the receiving antenna 1 to the signal source - Δн ₁ , the navigation error of pointing the transmitting antenna 3 to the subscriber station - Δн ₂ , the error of precise guidance receiving antenna 1 to the signal source - Δtn, the error of the programmed movement of the transmitting antenna 3 - Δpp.

The error in elevation in this mode includes Δn ₂ and Δpp.

Errors Δn ₁ and Δn ₂ arise due to the error in determining the location of the ground signal source, repeater and subscriber station.

In azimuth, Δn ₁ and Δn ₂ respectively characterize the errors in determining ψ _and and ψ _c in formula (1). Elevation error? H ₁ characterizes finding PA _When in formula (2), and? H ₂ - finding the error PA _pc in equation (10).

Both errors (Δn ₁ and Δn ₂ ) are random. Their values correspond to the initial pointing mode of the repeater and do not change during operation (with a stationary signal source, repeater and subscriber station).

When using a spacecraft as a signal source, instead of an error Δn _1, an error of uncertainty (inaccuracy of determination) of the angular position of the spacecraft - Δka occurs.

This error is random and can change during operation within the specified limits.

Errors Δtn and Δpp are random and during operation can vary within specified limits.

In the mode of transmitting information of the repeater, the indicated errors of the programmed guidance of the transmitting antenna 3 in azimuth and elevation (in the initial guidance mode) are supplemented with systematic errors caused by departures of the base of the repeater. Their maximum values are equal to the permissible values ΔAz _sd and ΔUM _sd, respectively.

In addition, similarly to the error Δtn, there are total random errors in azimuth and elevation, respectively, Δca and Δcu, including errors of the summands in formulas (19).

Analysis of random errors is carried out for the normal distribution law. In this case, the maximum error corresponds to the 3σ level, the probability of exceeding which is P = 2.7 · 10 ^-3 .

In the absence of base drifts, the probability of a “false” inclusion of the correction operation of the program angle of the transmitting antenna 3 corresponds to the probability of fulfilling the condition P _1A (Δс≥Δaz _sd ) or P _1U (Δс≥ΔUM _sd ).

As a result of the “false” inclusion of the correction operation, an additional random error of pointing the transmitting antenna 3 occurs, respectively, ΔAz _sd or

ΔUM _sd In this case, the initial value ΔAz _sn or ΔUM _sn changes, respectively, by the value ΔAz _sd or ΔUM _sd .

Therefore, in the next auto-tracking operation, the probability of “false” switching on the operation of correcting the program angle of the transmitting antenna 3 decreases and corresponds to the probability of fulfilling the condition P _2A (Δca≥2ΔAz _sd ) or P _2U (Δс≥2ΔUM _sd ).

The probability of a random error of 2ΔAz _sd or 2ΔUM _sd is equal to the product, respectively, P _1A P _2A or P _1U P _2U .

Choosing

provide the values of these random errors in pointing the transmitting antenna 3, respectively, ΔAz _sd and ΔUM _sd . Those. These random errors occur only during the first auto tracking operation.

Given the combination of random and systematic errors, to find the total errors of the software guidance of the transmitting antenna 3 in the mode of transmitting information at the ground source of the signal, in azimuth and elevation, respectively, use the formula

When using a spacecraft as a signal source in formula (24), the error Δn _{1 is} replaced by Δka.

For the considered example of a repeater, the analyzed errors have the following meanings: Δca = Δcu = 1.4 angular minutes, Δpp = 2 angular minutes, Δn ₁ = Δn2 = 3 angular minutes.

The indicated navigation errors Δn ₁ and Δn ₂ correspond to an error in determining the coordinate (according to the 3σ level) of the object (ground source, repeater, subscriber station) of 20 meters and the distance between the objects is 30 kilometers. This error decreases linearly with increasing distance between objects.

For modern geostationary spacecraft Δka does not exceed 3 arc minutes.

To ensure the conditions (23) choose:

ΔAz _sd = 1 / 2Δsa = 0.7 arc minutes,

ΔUM _sd = 1 / 2Δsu = 0.7 arc minutes.

From formulas (24) and (25), respectively, ΔΣА = 5.4 arc minutes; ΔΣU = 4.4 arc minutes.

Direct measurement of ΔГП3 and ΔГП4 for the considered example makes it possible to increase the accuracy of determining ΔΣУ by 10% (from 4.9 to 4.4 arc minutes) for a horizontal error of 2 arc minutes and by 18% (from 5.4 to 4.4 arc minutes) for non-horizontal error 3 arc minutes.

The above description of the method allows the following conclusion.

Introduced in this method, additional operations can improve the accuracy of pointing the transmitting antenna of the repeater to the subscriber station by 1.5-2.5 times, which leads to an increase in the speed of transmitted information and an improvement in the interference environment.

Compensation of the departures of the repeater base during operation makes it possible to abandon expensive bulky structures, increase the mobility of communication systems, and use repeaters in hard-to-reach areas.

The implementation of the invention allows to abandon the use of high-precision expensive equipment, which should be used in the construction of measuring reference planes.

According to estimates, due to the simplification of the equipment (the exclusion of a high-precision radio compass with spaced antennas and a local vertical), the mass of the repeater is reduced by 40-50 kg, power consumption is reduced by 20-30 watts. At the same time, the cost of the repeater is reduced by 15000-25000 cu

Claims (1)

The method of pointing the antennas of the repeater, in which the receiving antenna of the repeater is pointing at the signal source, and when pointing, the receiving antenna is rotated in azimuth and elevation until the signal is captured, and then the exact antenna is guided in azimuth and elevation using software guidance and auto tracking with correction for the received signal, and also programmatically guide the transmitting antenna of the repeater to the subscriber station at the calculated azimuth and elevation angle, excellent characterized in that the initial pointing mode of the repeater is introduced, in this mode, before pointing the receiving antenna to the signal source, it is set in azimuth to an angle that differs 90 ° from the direction to the signal source, and the angle of the base of the repeater relative to the horizon is measured using an angle sensor, mounted on the azimuthal axis of the receiving antenna, then the receiving antenna is rotated first in elevation to the calculated angle of the signal source, taking into account the measured angle of the base of the repeater, and then m azimuthal turn until the signal is captured, after which, in the mode of accurately pointing the receiving antenna to the signal source after the auto-tracking operation, the azimuth and elevation angle of the signal source are specified, and in this mode, using the angle sensor, measure the base angle of the repeater relative to the horizon plane, found in In the exact pointing mode of the receiving antenna, the angles are input into the computing device and used as initial values in the subsequent operation of correcting the program azimuth and elevation angle of the subscriber with communications in the repeater information transmission mode, in addition, the signal source azimuth and the relay base angle relative to the horizon plane are used to find the program azimuth of the subscriber station in the initial pointing mode of the relay, after which the receiving antenna is installed in azimuth at an angle different from the azimuth of the subscriber station at 90 °, and then the receiving antenna is installed at an angle corresponding to the azimuth of the subscriber station, in both positions the angle is measured using an angle sensor the base of the repeater relative to the horizon, the measurement data is used to determine the corrections of the azimuth and elevation angle of the subscriber station, after which the receiving antenna is azimuthally directed to the signal source and programmed in accurate guidance, and the transmitting antenna is guided by the calculated azimuth and elevation s taking into account the corrections found to the subscriber station, then in the mode of transmitting information of the repeater cyclically after each operation of auto-tracking of the receiving antenna in the calculation The diesel device introduces the current values of three parameters: the azimuth and elevation angle of the receiving antenna, as well as the angle of rotation of the receiving antenna, determined using the angle sensor, then find the differences between the current and initial values of these parameters, determine the departures of the base of the repeater based on the measurement results of these three parameters and find corrections to the program values of the azimuth and elevation angle of the subscriber station, the found corrections of both angles are compared with permissible deviations, and then at If the permissible deviation is exceeded by one or both amendments, the program value of that angle of the subscriber station, the deviation of which from the program value exceeds the permissible value, is corrected; at the same time, for the given angle of the subscriber station, the initial values of the base angle of the repeater are corrected, as well as the initial value of the correction to the program value this angle, then carry out the software guidance of the transmitting antenna to the subscriber station at the corrected angles.

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