JPH11326477A - Antenna control device and antenna control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antenna control device by which radio wave from an artificial satellite, even an artificial satellite operating on an inclined orbit, can be acquired in a short time. SOLUTION: A search region, by which a region to be searched is shown, relative to an artificial satellite operating on an inclined orbit, is inputted from the outside, and a preferable search pattern is decided by a search pattern decision means 22 based on the search region. As for the search pattern, an elliptic shape pattern or a linear folded type pattern is selected. Especially, in the case that the search region is a quadrilateral, search times required by respective search patterns are calculated and a search pattern requiring a shorter search time is decided. A concrete command angle of an antenna is produced by an antenna command angle generation means 24 based on the decided search pattern. The command angle is provided to an antenna 28 through an antenna drive means 26, to thereby enable to rapidly search the inside of the search region.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a satellite communication earth station. In particular, the present invention relates to an antenna control device and control method used in the earth station.

[0002]

2. Description of the Related Art Satellite communications using so-called geostationary satellites are widely used. Since this geostationary satellite appears to be stationary when viewed from the earth, communication between the satellite and the earth station can be performed by pointing the antenna of the earth station to the direction where the geostationary satellite exists. Can be.

[0003] However, some geostationary satellites have poor geostationary accuracy, and errors may occur in the direction of the antenna of the earth station.

[0004] Therefore, when starting satellite communication, the direction of the antenna is changed in a predetermined pattern to capture the position of the geostationary satellite.

As a pattern for changing the directivity of the antenna, a so-called spiral pattern is widely used. FIGS. 16A and 16B are explanatory diagrams (graphs) showing the state of the conventional spiral pattern. These graphs are graphs showing patterns in which the directivity direction of the antenna changes. In this graph, the horizontal axis is the azimuth axis, and the vertical axis is the elevation axis. The origin of this graph is the position where the geostationary satellite to be acquired should exist. That is, when the so-called geostationary accuracy of the geostationary satellite is good, the radio wave from the geostationary satellite should be able to be received by directing the direction of the antenna to the origin of the graph. However, as described above, in a geostationary satellite having poor geostationary accuracy, the position of the geostationary satellite may be shifted from the origin.

In the pattern shown in FIG. 16A, first, the directivity direction of the antenna is directed to the origin. Next, as shown in this figure, the directional direction of the antenna is spirally moved about this origin. In this way, the directional direction of the antenna is changed outward in a helical manner with the origin at the center, and an azimuth that can receive the strongest radio wave from the geostationary satellite is searched. Finally, the direction of the antenna is directed to the direction in which the radio wave from the geostationary satellite can be received most strongly.

Further, depending on the antenna (the structure of the driving device for driving the antenna), a case in which a smooth spiral movement as shown in FIG. In such a case, a rectangular spiral pattern is used as shown in FIG. In this pattern, as shown in this figure, only the movement of the antenna in the direction parallel to the azimuth axis or the movement parallel to the elevation axis is used. Therefore, it is not necessary to control the movement in the azimuth axis direction and the movement in the elevation axis direction at the same time, and the control for changing the directing direction of the antenna is simplified. In the change pattern of the directivity shown in FIG. 16B, the antenna is first directed toward the origin at the start of communication, and the directivity of the antenna is gradually changed outward from the direction.

[0008]

As described above, in the prior art, the directivity of the antenna is first directed to the direction where the geostationary satellite is originally located, and the directivity of the antenna is changed in a spiral from the origin. As a result, the search area was gradually expanded. Then, the directional direction of the antenna was ultimately directed to the direction in which the radio wave from the geostationary satellite was most strongly received.

[0009] Such a method of controlling an antenna brings about a favorable result for a geostationary satellite having extremely good geostationary accuracy. That is, it is possible to quickly capture a geostationary satellite.

However, in recent years, artificial satellites operating in so-called inclined orbits are often used. The above-described conventional antenna control method has a problem that the acquisition efficiency is poor for such artificial satellites operating in inclined orbits.

[0011] This problem will be described in detail below. An explanatory diagram for explaining this problem is shown in FIG. In this figure, the moving orbit of the artificial satellite is represented by the inclined orbit 10. Since the artificial satellite is moving on the inclined orbit 10, it is necessary to change the directing direction of the antenna based on some pattern to check the exact direction of the artificial satellite in order to know the exact direction of the artificial satellite. There is.

By performing a search operation using a spiral pattern as shown in FIG. 16 (1) with respect to an artificial satellite operating in such an inclined orbit, for example, as shown in FIG.
It is considered that an effective search operation is performed when the pointing direction of the antenna is in the vicinity of the inclined trajectory 10, but it is considered that there is almost no point in searching where the pointing direction of the antenna is far away from the inclined trajectory 10. . In FIG. 17, a region far from the inclined trajectory 10 is shown as a waste region 12. Thus, in the conventional spiral pattern, a useless search operation is performed,
It was difficult to capture satellites quickly.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide an antenna control apparatus capable of quickly capturing a geostationary satellite operating in an inclined orbit or an artificial satellite having poor position accuracy. It is to be.

[0014]

SUMMARY OF THE INVENTION The present invention is directed to an antenna control device for capturing the direction of the artificial satellite by searching for a radio wave emitted by the artificial satellite, and pointing the antenna to the captured direction. Search area input means for inputting a target search area; search pattern determining means for determining a search pattern that is a pattern in which the antenna searches the search area based on a shape of the search area; An antenna command azimuth angle generating means for generating an azimuth angle of an antenna to be instructed to the antenna based on a pattern, and an antenna driving means for driving the antenna based on the antenna azimuth angle. It is.

The present invention is characterized in that the search pattern determining means determines an elliptical pattern as a search pattern when the input search area is round or elliptical.

[0016] In the present invention, the search pattern determining means may be arranged such that, when the input search area is rectangular,
A time required for searching the search area by two or more search patterns is calculated, and the search pattern having the shortest search time is selected.

The present invention is characterized in that the two or more search patterns include an elliptical pattern and a straight folded pattern.

The present invention is characterized in that it includes a search end determining means for determining a search end timing based on the intensity of a reception level from the artificial satellite received by the antenna.

According to the present invention, in order to capture the azimuth of the artificial satellite having a large positional drift in orbit, the search pattern determining means includes a part of a search range superimposed,
During a search operation, a search pattern that allows a part of the already searched range to be searched again is determined.

According to the present invention, the antenna driving means drives the antenna at a high speed when the directional direction of the antenna is out of the search area.

In the present invention, when the command angle of the generated antenna is out of the search area, the antenna command angle generating means generates the azimuth angle of the next position to enter the search area as the command angle. It is characterized by the following.

According to the present invention, there is provided a first step in which the directional direction of the antenna is moved in a predetermined search pattern so that the antenna can receive radio waves from artificial satellites. After a state in which radio waves from an artificial satellite can be received is achieved, the pointing direction of the antenna is moved in a predetermined direction by a predetermined amount, and a second step of finding an azimuth in which the radio waves from the artificial satellite are more strongly received, It is characterized by including.

In the present invention, in the second step, the directivity direction of the antenna is shifted by ± d (d is a positive real number) in the azimuth axis direction so that the radio wave from the artificial satellite can be received more strongly. It is characterized by finding the direction.

According to the present invention, in the second step, the pointing direction of the antenna is shifted by ± d (d is a positive real number) in the elevation axis direction to receive radio waves from the artificial satellite more strongly. It is characterized by finding a possible direction.

In the present invention, d is a number greater than the maximum angle from the directional direction of the antenna in a beam area in which the antenna can receive radio waves from the artificial satellite. .

[0026]

Preferred embodiments of the present invention will be described below with reference to the drawings.

Embodiment 1 The antenna control apparatus according to the first embodiment is provided with a search area from the outside, and searches in the given search area.
In other words, the pointing direction of the antenna is changed inside a given search area, and an attempt is made to detect in which direction in the search area the geostationary satellite (hereinafter simply referred to as a satellite) is located.

As described above, in the first embodiment, it is assumed that the search area is provided from the outside.
An example of this search area is shown in FIG. For example, FIG. 1A shows an example in which an elliptical shape is used as an approximation of a region where a satellite performing an inclined orbit operation exists. In this figure, the region where the satellite exists, that is, the search region 14 is represented as the azimuth on the graph. In the graph shown in FIG. 1A, the horizontal axis is the azimuth axis, and the vertical axis is the elevation axis. Thus, a coordinate system including the azimuth axis and the elevation axis is often called an antenna coordinate system.

The satellites operating in inclined orbit are:
The position in the latitudinal direction fluctuates as compared with a conventional satellite in which position control is well performed. Therefore, it is also preferable to perform approximation with a tilted rectangle as shown in FIG. 1 (2) as a region where such a satellite can exist (search region 14). The graph shown in FIG. 1 (2) is also a graph on the antenna coordinate system in which the horizontal axis is the azimuth axis and the vertical axis is the elevation axis. The search area 14 shown here is represented by a rectangle.

The antenna control apparatus according to the first embodiment is supplied with the search area 14 approximated by an ellipse or a rectangle from the outside, drives the antenna based on the search area 14, and changes the direction of the antenna. Things.

In the example shown in FIG. 1, only the elliptical shape (FIG. 1 (1)) and the quadrangular shape (FIG. 1 (2)) are shown. The area 14 may of course be used.

FIG. 2 is a block diagram showing the configuration of the antenna control apparatus according to the first embodiment. As shown in FIG. 2, the antenna control device includes a search area input means 20 for inputting the search area 14 first. The search area 14 is an area where the satellite exists as described above, and specifically, is an area represented by an ellipse or a rectangle as shown in FIG. For example, in the case of a rectangle, the search area 14 is defined by the coordinates of each vertex. For example, in the case of an ellipse, the search area 1
Reference numeral 4 denotes the coordinates of the focal point.

The search pattern determining means 22 determines a search pattern based on the type of the search area 14 input by the search area input means 20.

The features of the first embodiment are as follows.
That is, the search pattern determining means 22 determines the type of the search pattern based on the type of the shape of the search area 14. Since the type of the search pattern is also determined according to the type of the search area 14, the search in the search area 14 can be performed without waste, and the satellite can be quickly acquired.

The antenna command angle generating means 24 generates an antenna command angle which is an angle for commanding the directional direction of the antenna based on the search pattern determined by the search pattern determining means 22. This command angle is specifically expressed as an angle on the antenna coordinate system as described above. That is, the command angle is determined by the azimuth axis and the elevation axis.

The antenna driving means 26 drives the antenna 28 so as to direct the directional direction of the antenna to the angle generated by the antenna command angle generating means 24.

Further, the search end determining means 30 constantly monitors the reception level of the satellite signal received by the antenna 28. When it is determined based on this monitoring that the antenna 28 has been able to direct its pointing direction to the satellite, the search end determining means 30 supplies a predetermined control signal to the antenna driving means 26 and the like in order to end the search. I do. Upon receiving this control signal, the antenna command angle generating means 24 stops generating a new command angle. When receiving the control signal, the antenna driving unit 26 stops driving the antenna 28.

The characteristic of the antenna control apparatus according to the first embodiment is that the supplied search area 1
That is, the search pattern determining means 22 determines the type of the search pattern based on the four types. A specific method of determination will be described below.

The antenna control apparatus according to the first embodiment has two types of search patterns. That is, the search pattern determining means 22 selects one of the two types of search patterns based on the shape of the search area. These two types of search patterns are shown in FIGS. 3 (1) and (2). The search pattern shown in FIG. 3A is an elliptical search pattern. FIG.
The search pattern shown in (2) is a straight-turning type search pattern. Search pattern determining means 22
Selects one of the two types of search patterns shown in FIG. 3 based on the input search area 14. An explanatory diagram of this specific selection method is shown in FIG. As shown in FIG. 4, when the shape of the given search area 14 is round or elliptical, an elliptical pattern is used as a search pattern as shown in FIG. select. This is search area 1
If 4 is round or elliptical, the straight folded pattern is clearly inappropriate.

Next, when the shape of the given search area is a quadrangle, the calculation of the time required for the search is first performed for both of the search patterns shown in FIGS. 3 (1) and 3 (2). Try. First, when a search is performed using an elliptical pattern, the time required to search the entire search area 14 is calculated. This search operation starts from the center of the rectangular search area 14 and calculates the time until the search of the entire search area 14 is completed.

Next, when the straight folded pattern is used as the search pattern, the time required to search the entire rectangular search area is calculated. The search based on this search pattern starts from the vertex at the left corner of the rectangular search area 14.

In this way, the time required for the search is calculated for the two types of patterns, the elliptical pattern and the linear folded pattern, and the search pattern that can be searched in a shorter time is selected. The search pattern determining means 22 selects an appropriate search pattern for the given search area 14 by the above processing.

In this way, the search pattern determining means 22 determines either the elliptical pattern or the linear folded pattern. Next, the antenna command angle generation means 24 generates an angle to specifically command the antenna 28 based on the determined pattern. A specific method of generating an angle will be described below.

FIG. 5 is an explanatory diagram of a method of generating a specific command angle of a search pattern to be supplied to the antenna 28 when the elliptical pattern is determined by the search pattern determining means 22.

As shown in the figure, the elliptical pattern first supplies the supplied center coordinates of the search area 14 to the antenna 28. As a result, the antenna 28
Is directed toward the center of the search area 14.

Next, the antenna 28 is moved in the azimuth direction by the length of the beam area 40 in which the antenna 28 can recognize radio waves from the satellite. As a result, the pointing direction of the antenna 28 is shifted from the center direction of the search area 14 by the length of the major axis.

Next, the beam area 40 of the antenna 28 is rotated once with respect to the center of the given search area 14 so as to draw an elliptical orbit at a predetermined ratio. This elliptical orbit is an elliptical orbit requiring the same ratio as the ratio of the ellipse in the beam area 40.

Here, the fact that the beam area 40 becomes elliptical will be described. The beam area 40, which is an area in which radio waves from a satellite can be recognized, is often basically circular in a general antenna 28. However, when this beam area is displayed in the antenna coordinate system composed of the azimuth axis and the elevation axis as shown in the text, the elevation axis side becomes a closed shape, and forms an ellipse on the graph. The clogging ratio increases as the elevation angle increases. More precisely, if the elevation angle is θ, the relationship between the major axis a and the minor axis b of the beam region 40 is a = b / cos θ. Beam area 4
It is well known that 0 takes such a form.

As described above, the ratio between the major axis a and the minor axis b of the beam area 40 changes with the elevation angle θ. Therefore,
Even when a search is performed using an elliptical pattern, the ratio between the minor axis b and the major axis a of the beam area 40 changes as the elevation angle changes. In the first embodiment, the elevation angle at the center point of the given search area is given. Using the major axis a and the minor axis b
The ratio is fixed at a fixed value. This is because even in satellites operating in inclined orbit, the change in elevation angle is considered to be very small, so even if the elevation angle at the center coordinate of the given search area is used as a representative, the error is considered to be small. Because. In this way, as shown in FIG. 5, a spiral search is performed in order from the center of the search area using the elliptical beam area 40. That is, the beam area 40 is moved so that the beam area 40 moves outward from the center point of the search area 14 by the major axis a every time the circle travels around the elliptical orbit, and the elliptical orbit is caused to circle around the center point of the search area 14 as a center. It is. By repeating such a search operation a predetermined number of times, a search can be finally performed for the entire search region 14 given.

FIG. 6 is an explanatory diagram showing a specific manner in which the directivity of the antenna is changed by the linear folded pattern. Such a linear folded pattern is employed when the shape of a given search area 14 is a quadrangle as described in FIG. Then, as described in FIG. 4, when this straight folded pattern is adopted, the directivity of the antenna is first directed to the vertex of the left corner of the rectangle, and then a straight line is formed as shown in FIG. The search in the search area 14 is performed by turning back.

As shown in FIG. 6, the pitch of the straight line in the straight folded pattern is referred to as r in the text. As shown in FIG. 6, the return pitch r is determined by the width of the search performed by the movement of the beam area 40 in order to prevent an unsearched portion from being left when the directional direction of the antenna is returned. It is desirable to make them equal. That is, when the beam area 40 performs a reciprocating operation,
If the reciprocating operation is performed such that the peripheral portion of the beam area 40 is in direct contact with the beam region 40, an efficient search operation can be performed without leaving a non-searched portion. Therefore, the turn pitch r is calculated by the following equation.

[0052]

R = (1 / (cos ² φ / a ² + sin ² φ /
b ² )) ^1/2/2 where φ is the angle at which the search area 14 is inclined,
a is the major axis of the beam region 40, and b is the minor axis of the beam region 40. In this way, by determining the turning pitch r, the straight line is turned so that the edges of the beam area 40 are in contact with each other, and the search area 14 can be searched efficiently.

Embodiment 2 In the first embodiment, an elliptical pattern or a linear folded pattern (see FIG. 3)
In, each pattern is created such that the beam regions 40 are in contact with each other.

However, there are many satellites whose positions fluctuate with time. When capturing a satellite having such a so-called time drift, the situation where the beam region 40 is moved so that the beam region 40 is in contact only at the side portion as described in the first embodiment. In some cases, satellites cannot be acquired due to the influence of the time drift. For example, if the elliptical pattern is configured so that the beam regions 40 are completely touching as shown in FIG.
If the beam area 40 has already moved and has moved into the searched area, the beam area may not be able to capture the satellite because the searched area is not searched again.

As described above, in order to prevent a case where the satellite cannot be acquired due to the drift of the satellite, it is possible to configure a search pattern in which each beam area 40 has an overlapping area little by little when moving. preferable.

FIG. 7 shows that when the beam area 40 is moved in this manner, a certain overlapping area 50 is provided between the beam areas 40.
An example is shown in which a search pattern is configured so as to generate. The search pattern shown in FIG. 7 is an elliptical pattern. For example, one round of the elliptical orbit is searched with the major axis a1, and then the beam area 40 searches for the elliptical orbit with the major axis a2. According to the first embodiment shown in FIG. 5, there is a difference between the major axis a1 and the major axis a2 by twice the major axis of the beam area 40, that is, by 2a.

On the other hand, in the second embodiment, the difference between a1 and a2 is set to be smaller, and the search pattern is formed so that a constant overlapping area 50 is generated as shown in FIG. Therefore, in the overlap region 50, the search is performed both in the case where the beam region 40 performs one round search with the long diameter a1 and in the case where the beam region 40 performs one round search with the long diameter a2. Therefore, if the amount of time drift of the satellite is smaller than the width of the overlapping area 50, it is possible to prevent a situation in which the satellite cannot be acquired due to the time drift.

Hereinafter, in order to form the overlapping area 50,
How to determine the major axis a1 and the major axis a2 will be described.

First, the length of one round of an elliptical orbit is generally 4a.
It is known that it is represented by E (k). Where a
Means a major axis such as a1 or a2 as shown in FIG. E and k are represented by the following equations.

[0060]

## EQU2 ## k = (1- (b)^Two/ A^Two))^1/2 E (k) = (π / 2) · (1− (1/4) k^Two -(3 /
64) k^Four-(5/256) k⁶−…) Now, if the position of the antenna in the directional direction is represented by δ,
The degree (the change amount of the azimuth angle per unit time) is dδ / d
It is represented by t. Therefore, this velocity and the elliptical orbit described above
The time required to make an orbit around an elliptical orbit based on the length of one orbit
Time is required. This time is represented by the following equation.

[0061]

[Equation 3] (4aE (k)) / (dδ / dt) Next, by multiplying the time required for making a round of this elliptical orbit by the drift velocity of the satellite to be acquired, the beam area 40 is obtained. It is required how much the satellite moves during one round. If the overlap region 50 is determined by the same amount as the amount of movement of the satellite during the time of one round of the search operation in this way, it is considered that acquisition does not fail even if a time drift occurs in the satellite (see FIG. 7). ).

As described above, when searching for a satellite with an elliptical pattern, the overlapping area 50 is obtained as described above.

Next, it is conceivable to provide such an overlapping region also in the case of a linear folded type pattern as shown in FIG. A method of obtaining the overlap region 50 when the straight folded pattern is employed will be described below.

FIG. 8 is an explanatory view showing a case where the folding pitch is reduced in order to provide the overlapping region 50 when the linear folding type pattern is adopted. If the folding pitch is smaller than the folding pitch r in the first embodiment, the overlapping region 50 having the reduced width is provided. As described above, the width of the overlap region 50 in the case where the linear folded pattern is adopted is also the maximum period in which the search is performed in the overlap region 50 where the beam region 40 overlaps in the same manner as in the case where the above-described elliptical pattern is adopted. If the amount of drift of the satellite is obtained in between, and the overlapping region 50 having a width larger than the drift amount is provided, it is considered that satellite acquisition failure can be prevented.

First, as shown in FIG. 8, it is easily understood that the search cycle of the folded portion becomes the longest in the linear folded pattern. As shown in FIG. 8, for example, the beam area 40 moves along the search pattern from the start point, and again overlaps the beam area 40 at this start point with a distance of 2L + r.
This is after the beam area 40 has moved by the distance. It can be easily understood from FIG. 8 that the time required for the beam area 40 to move by this distance is the longest as the search cycle. Note that the distance was previously described as 2L + r, but this r is
This is the folded pitch, which is exactly r- (overlap area 5
0 width). However, here, for the sake of approximation, the folded pitch is approximated by r as in the first embodiment. As a result, the longest period of the search performed by searching the beam region 40 is represented by the following equation.

[0066]

## EQU4 ## (r / (dδ / dt)) + (2L / (dδ / d)
t)) + α Here, r is an approximate value of the turning pitch in FIG. 8 as described above. L represents the length of the straight line folded as shown in FIG. Dδ / dt is a change in the azimuth of the beam area 40 per unit time, that is, the moving angular velocity of the antenna 28 in the pointing direction. And α
Is based on the acceleration of the antenna 28. That is, as shown in FIG. 8, the moving direction of the antenna 28 changes its moving direction twice at the time of turning back. Α is used as the time required for the change in the moving direction. This α is known to be represented by the following equation.

[0067]

Α = 2 × ((dδ / dt) / (d ² δ / d ² t)) Here, as described above, dδ / dt represents the angular velocity of the antenna 28 in the directivity direction, and d ² δ / d ² t represents the driving acceleration of the antenna 28.

Thus, the beam area 4
The time required for 0 to move 2L + r is determined.
By multiplying the time obtained in this manner by the drift speed of the satellite to be acquired, the amount of movement of the satellite during one round trip of the beam area 40 can be determined as shown in FIG. Therefore, if the overlapping area 50 is set to be larger than the amount of movement of the satellite, it is possible to prevent satellite acquisition failure.

As described above, according to the second embodiment, the search pattern is configured such that a constant overlapping area 50 is generated as the beam area 40 moves. As a result, an antenna control device that can capture the satellite even if the satellite has a time drift is obtained. In addition, Embodiment 2
The configuration block itself of the antenna control apparatus according to the third embodiment is the same as that of the first embodiment, and has the configuration shown in FIG.

Embodiment 3 In the first and second embodiments, the search in the search area can be performed more quickly by selecting the elliptical pattern or the linear folded pattern according to the shape of the given search area.

However, for example, when the search area 14 is given as a rectangular shape, an elliptical pattern may be selected. This is because, as described with reference to FIG. 4, the search time when two patterns of the elliptical pattern and the linear folded pattern are applied to the search area 14 is calculated, and the shorter one is selected. Therefore, an elliptical pattern may be selected depending on the shape of the search area 14.

As described above, when an elliptical pattern is selected for the rectangular search area 14, an area where the search is useless often occurs as shown in FIG.

As shown in FIG. 9A, the search pattern (shown by a broken line in FIG. 9A) protruding from the search area 14 is shown.
It is a useless part.

Therefore, in the third embodiment, for the portion where the search pattern is outside the search area 14, the moving speed of the antenna in the transition direction is set to the search area 1
4 It is proposed to increase the speed compared to the inside.

In the search area 14, in order to receive and process a radio wave from a satellite, the moving speed of the antenna 28 in the directional direction needs to be lower than a certain fixed speed so as to be in time for the processing. is there. However, when moving a portion other than the search area 14, it is not necessary to process radio waves from satellites, so that the pointing direction of the antenna 28 can be moved at high speed. When the pointing direction of the antenna 28 enters the search area 14 again, the moving speed in the pointing direction of the antenna 28 is reduced again to a speed lower than a certain speed, and the processing of the radio wave from the satellite is performed. I can do it.

FIG. 10 is a block diagram showing the configuration of an antenna control apparatus for moving the directivity of the antenna 28 at high speed in a search pattern other than the search area 14 as described above.
Is shown in

As shown in the figure, the antenna control apparatus according to the third embodiment includes a search area input means 20 for inputting a search area 14 and a search pattern determination means 2.
2 and an antenna command angle generation means 24. These configurations correspond to the first embodiment shown in FIG.
The configuration is exactly the same as that of the antenna control devices of the first and second embodiments.

A characteristic configuration of the configuration shown in FIG. 10 is the search area deviation processing means 60. This means receives the command angle generated by the antenna command angle generating means 24, and searches the search area 1 given this command angle.
4 is determined, and if it is, the command angle is supplied to the antenna driving means 26 at high speed in order to drive the antenna 28 at high speed. The search area departure processing means 60 causes the search area 1
The drive speed of the antenna 28 can be increased in portions other than the portion 4, and a more rapid search can be performed. As a result, according to the third embodiment, a satellite can be acquired more quickly.

As shown in FIG. 10, the output signal of the search area departure time processing means 60 is given to the antenna driving means 26, and the antenna driving means 26 drives the antenna 28 based on the received command angle. When the search pattern does not deviate from the search area 14, that is, when the search pattern is inside the search area 14, the command angle received from the antenna command angle generating means 24 is directly sent to the antenna driving means 26. Supply. Therefore, the operation when searching inside the search area 14 is exactly the same as in the first and second embodiments.

Further, FIG.
0 is also provided, but this operation is exactly the same as FIG. 2 showing the configuration of the first and second embodiments.

As shown in FIG. 9A, the third embodiment is mainly proposed for a case where the search area 14 is rectangular and the search pattern is elliptical. However, even when the search area 14 is given in an elliptical shape, a useless portion may similarly occur (see FIG. 9B). Even in the case as shown in FIG. 9 (2), if it deviates from the search area 14, the antenna 28 in the search pattern
By setting the moving speed to high, a quick search can be performed as in FIG. 9A, and a satellite can be quickly acquired.

As shown in FIG. 9 (2), even when a search is performed using an elliptical pattern, a useless portion occurs because the elliptic ratio of the elliptical pattern is originally determined by the elliptic ratio of the beam area 40. On the other hand, when the search area 14 has an elliptical shape, the ellipticity ratio depends on the angle of the satellite's inclined orbit. Therefore, if the two elliptic ratios do not match, FIG.
A useless portion as shown in (2) may occur.

As described above, according to the third embodiment, a portion other than the search area is quickly searched, so that a satellite can be quickly acquired.

Embodiment 4 In the third embodiment, when the directional direction of the antenna deviates from the search area, the antenna 28 is driven at a high speed.
This allowed for a quicker search.

However, when the beam area 40 moves in a portion other than the search area 14, the operation is useless after all. Therefore, returning to the search area 14 more quickly can shorten the search time. It is clear that this contributes to

Therefore, in the fourth embodiment, when it is determined that the directivity of the antenna has entered an area other than the search area 14, the search pattern to be traced in the future is inspected.
Next, until the position (azimuth) where the vehicle enters the search area 14,
The directional direction of the antenna 28 was moved at high speed ignoring the search pattern. As shown in FIG. 11, when the directional direction of antenna 28 comes out of search area 14 while moving the directional direction of the antenna in search area 14, the antenna control apparatus according to the fourth embodiment will The search pattern was ignored, and the pointing direction of the antenna was moved at a high speed to the point where it entered the search area 14 next. In general, it is considered that it is better to connect a point that enters a straight line and a point at which the vehicle enters the high-speed movement path. However, considering the acceleration of the antenna 28, it is ultimately better to follow a path that is as smooth as possible. The time is considered to be shorter. Therefore, in the present embodiment, simply “exited point” and next “entry point”
Instead of moving the line with a straight line, we decided to follow the path that would move the fastest. As this route, a route that can move fastest is selected in consideration of the acceleration of the antenna 28 and the like.

The configuration of the antenna control apparatus according to the fourth embodiment is almost the same as the configuration of the antenna control apparatus of the third embodiment, and has the configuration shown in FIG. In the configuration shown in FIG. 10, the search area departure time processing means 60 differs from the third embodiment in that the search area departure point from the search area 14 and the reentry point as shown in FIG. The process of moving between the spaces at high speed is performed.

That is, the search area deviation processing means 60
If it is determined that the direction of the antenna has deviated from the search area 14, the search follows the search pattern supplied from the antenna direction angle generation means 24, and calculates the point at which the direction of the antenna falls within the search area. I do. Then, the search area departure time processing means 60 calculates a route connecting the current directional direction of the antenna 28 to the point of re-entering obtained in the above calculation in the shortest time, and moves this route at high speed.

As described above, according to the fourth embodiment, when the directional direction of antenna 28 moves in a part other than search area 14, search area 14 is re-established in the shortest time.
As a result, the antenna control device can acquire the satellite more quickly.

Embodiment 5 FIG. 12 shows a graph of a typical reception sensitivity pattern of the antenna 28.
In this graph, the horizontal axis represents the deviation angle from the directional direction of the antenna, and the vertical axis represents the receiving sensitivity. The direction where the angle is 0 is the directivity direction of the antenna itself, and in this direction, the reception sensitivity usually takes the maximum value. The portion having high reception sensitivity centered on the antenna directional direction is usually called a main lobe.

Although depending on the configuration of the antenna 28, generally, a so-called side lobe is generated in a direction deviated by a fixed angle from the directional direction of the antenna. In the example shown in FIG. 12, a first side lobe and a second side lobe are illustrated.

In the antenna 28, the absolute value of the receiving sensitivity is generally large in the main lobe, but the first side lobe and the second side lobe can also receive radio waves from the satellite.

Therefore, as shown in FIG.
Even if the directional direction of the antenna 28 is moved according to a predetermined search pattern and a radio wave from the satellite is received in the azimuth A, the radio wave from the satellite is not always received in the main lobe. For example, reception may be performed in the first side lobe or the second side lobe shown in FIG. Therefore, in the direction A shown in FIG.
Even if radio waves from the satellite can be received when the antenna is pointed, it cannot be concluded that the satellite exists in the azimuth A direction.

That is, the search patterns as shown in the above-described first to fourth embodiments and FIG. 13 are search patterns for finding out where the satellite exists. Therefore, the above-described beam region 40 generally includes not only the main lobe but also the first side lobe and the second side lobe. Hereinafter, in the fifth embodiment, a case where the beam area 40 extends to the second side lobe will be described.

Embodiment 5 proposes a method for more accurately determining the direction of the satellite after receiving the radio wave of the satellite.

The technique proposed in the fifth embodiment is as follows.
After receiving a radio wave from the satellite in the azimuth A shown in FIG. 13, a small search pattern is drawn around this azimuth A to search for a beam peak point at which the radio wave received from the satellite is maximum. More specifically, as shown in FIG. 14, the directional direction of the antenna 28 is moved in the azimuth direction by ± d around the azimuth A, and a peak at which the intensity of the received radio wave is the strongest is found. Then, the direction of the antenna is further moved in the elevation direction by ± d from the position of the peak to find a peak at which the intensity of the received radio wave is the highest.

As described above, if the direction in which the intensity of the radio wave received from the satellite is finally found is found, the direction of the antenna coincides with the direction of the satellite. As a result, the antenna 28 can receive the radio wave from the satellite with the main lobe, and can receive the radio wave from the satellite with sufficient intensity.

Note that d shown in FIG. 14 is preferably set to an angle larger than the angle s2 of the second side lobe. That is, it is preferable to set an angle wider than the angle of the beam region 40. As shown in FIG. 12, the angle s2 of the second side lobe represents an angle from the directional direction of the antenna, that is, an angle of a difference from the main lobe. By making the small search pattern d in FIG. 14 larger than s2, even if the second side lobe is receiving the radio wave from the satellite, it can be surely received by the main lobe, and the radio wave from the satellite can be obtained. Can be favorably maintained.

Now, the operation of the antenna control method according to the fifth embodiment will be described with reference to flowcharts. FIG.
FIG. 5 shows a flowchart illustrating the operation of the antenna control method.

First, in the first step S15-1, the directional direction of the antenna 28 is moved so that the antenna 28 can receive radio waves from satellites. In this operation, as described in FIG. 13, the direction of the antenna 28 is moved in a predetermined search pattern to search whether or not a radio wave from a satellite can be received. As described in the first and second embodiments, a search pattern such as an elliptical pattern or a linear folded pattern (see FIG. 3) is selected as the search pattern. When the radio wave from the satellite is received in the first step S15-1 (for example, when the pointing direction of the antenna is directed to the point A in FIG. 13), the process proceeds to the second step S15-2. I do.

In the second step S15-2, so-called fine adjustment of the directivity of the antenna is performed so that the radio wave from the satellite can be received most strongly. That is, by moving the pointing direction of the antenna 28 within a range in which the satellite is expected to exist, a direction in which radio waves from the satellite can be received more strongly is searched. This operation is performed by moving the direction of the antenna in the azimuth direction or the elevation direction by a predetermined amount as shown in FIG. Then, as a result of the movement, the position where the radio wave from the satellite can be received most strongly is found. By the processing in the second step S15-2, the radio wave from the satellite can be received by the main lobe of the antenna 28 (see FIG. 12).

[0102]

As described above, according to the present invention, since the search pattern is determined based on the search area, it is possible to obtain an antenna control apparatus capable of quickly searching for an artificial satellite.

According to the present invention, when the search area is round or elliptical, an elliptical pattern is selected as the search pattern. As a result, an antenna control device that can more quickly search for an artificial satellite is obtained.

Further, according to the present invention, when the search area is a quadrangle, the search time for a plurality of search patterns is calculated, and a search pattern having a shorter time is selected. Therefore, the search time for the artificial satellite can be more reliably reduced.

According to the present invention, in particular, the plurality of search patterns for calculating the search time include an elliptical pattern and a linear folded pattern. Therefore, it is possible to find out a search pattern that allows a more rapid search for an artificial satellite.

Further, according to the present invention, since the end timing of the search is determined based on the reception level strength, the end of the search for the artificial satellite can be more reliably performed.

Further, according to the present invention, a search pattern in which a part of the search path overlaps is adopted in an area searched by the search pattern. Therefore, even if the satellite trying to capture radio waves drifts,
Radio waves from artificial satellites can be reliably captured.

Further, according to the present invention, when the directional direction of the antenna deviates from the given search area, the antenna is driven at a high speed, so that an artificial satellite search can be performed more quickly. Is obtained.

Further, according to the present invention, when the command angle of the antenna is out of the search area, the antenna is quickly driven to the azimuth of the next position to enter the search area. Therefore, an antenna control device capable of searching for an artificial satellite more quickly can be obtained.

Further, according to the present invention, after searching for a satellite, capturing a radio wave from the satellite, and moving the antenna in a predetermined direction, the azimuth for receiving the radio wave from the satellite more strongly can be determined. An antenna control method that can be found accurately can be obtained.

Further, according to the present invention, since the object is moved by ± d angle in the azimuth axis direction, it is possible to find the direction in which the radio wave from the artificial satellite can be more strongly received in the azimuth axis direction.

Further, according to the present invention, since the directivity direction of the antenna is shifted by ± d angle in the elevation axis direction, it is possible to find a direction in which the radio wave from the artificial satellite can be more strongly received in the elevation axis direction. it can.

According to the present invention, d is set to a value larger than the angle of the range of the beam area of the antenna. Therefore, it is possible to reliably find a position where radio waves from artificial satellites can be received more strongly.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram illustrating an example of an input search area.

FIG. 2 is a configuration block diagram of an antenna control device according to preferred embodiments 1 and 2 of the present invention.

FIG. 3 is an explanatory diagram illustrating an example of a search pattern.

FIG. 4 is an explanatory diagram illustrating an operation of selecting a search pattern based on an input search area.

FIG. 5 is an explanatory diagram showing a specific method of obtaining a search pattern of an elliptical pattern.

FIG. 6 is an explanatory diagram for explaining a specific method for obtaining a search pattern that is a straight-folding pattern.

FIG. 7 is an explanatory diagram illustrating a search pattern in a case where a search is performed using an elliptical pattern and a certain overlapping area is provided in the search range.

FIG. 8 is a diagram showing a search pattern in which a fixed overlapping area is provided in the search range when a linear folded pattern is employed, and the position of the satellite can be reliably captured even when the satellite has a position drift. FIG.

FIG. 9 is an explanatory diagram illustrating an operation in a case where the directivity direction of the antenna is moved at high speed in a portion of the search pattern that is off the search area.

FIG. 10 is a configuration block diagram of an antenna control device according to the third and fourth embodiments.

FIG. 11 is an explanatory diagram showing an operation in which, when a part of a search pattern is out of the search area, the pointing direction of the antenna is quickly moved to a point where the search pattern reenters the search area.

FIG. 12 is a graph showing a sensitivity distribution of an antenna.

FIG. 13 is an explanatory diagram showing that a radio wave from a satellite is captured at point A when a radio wave from a satellite is captured using an elliptical pattern as a search pattern.

FIG. 14 is an explanatory diagram of an operation when the directivity direction of the antenna is moved by ± d angles in the elevation direction and the azimuth direction.

FIG. 15 is a flowchart showing an operation of the antenna control method according to the fifth embodiment.

FIG. 16 is an explanatory diagram showing an example in which a conventional spiral pattern for capturing radio waves from a satellite is used as a search pattern.

FIG. 17 is an explanatory diagram of a case where a search is performed on a satellite operating in a so-called inclined orbit using a conventional spiral pattern.

[Explanation of symbols]

10 inclined orbit, 12 wasted area, 14 search area,
20 search area input means, 22 search pattern determination means, 24 antenna command angle generation means, 26 antenna drive means, 28 antennas, 30 search end determination means, 40 beam area, 50 overlap area, 60 search area deviation processing means.

Claims (12)

[Claims] 1. An antenna control apparatus for capturing an azimuth of the artificial satellite by searching for a radio wave emitted by the artificial satellite and directing an antenna to the captured azimuth, wherein a search area to be searched is input. Search area input means; search pattern determination means for determining a search pattern that is a pattern in which the antenna searches the search area based on the shape of the search area; and instructing the antenna based on the determined search pattern. An antenna control device, comprising: an antenna command azimuth angle generation unit that generates an azimuth angle of an antenna to be formed; and an antenna driving unit that drives the antenna based on the antenna azimuth angle. 2. The antenna control according to claim 1, wherein the search pattern determining means determines an elliptical pattern as the search pattern when the input search area is round or elliptical. apparatus. 3. The search pattern determining means calculates a time required to search the search area by using two or more search patterns when the input search area is a quadrangle. The antenna control device according to claim 1, wherein the search pattern is selected. 4. The antenna control device according to claim 3, wherein the two or more search patterns include an elliptical pattern and a straight-back pattern. 5. The search termination determining means for determining a search termination timing based on the strength of a reception level from the artificial satellite received by the antenna. An antenna control device according to any one of the above. 6. In order to capture the azimuth of the artificial satellite having a large position drift in orbit, the search pattern determining means has a part of a search range superimposed, and already searches during a search operation. 6. The antenna control device according to claim 1, wherein a search pattern that allows a part of the searched range to be searched again is determined. 7. The antenna driving means, when the directional direction of the antenna is out of the search area,
The antenna control device according to any one of claims 1, 2, 3, 4, and 5, wherein the antenna is driven at a high speed. 8. The antenna command angle generating means, when the generated command angle of the antenna is out of the search area, generates the azimuth angle of the next position to enter the search area as the command angle. The antenna control device according to any one of claims 1, 2, 3, 4, and 5, wherein: 9. A first step in which the directional direction of the antenna is moved in a predetermined search pattern so that the antenna can receive radio waves from a satellite, and in the first step, the antenna is connected to the satellite. After the state in which the radio wave from the satellite can be received is achieved, the pointing direction of the antenna is moved in the predetermined direction by a predetermined amount to find a direction in which the radio wave from the artificial satellite is received more strongly. An antenna control method, comprising: 10. The method of claim 2, wherein the directional direction of the antenna is shifted by ± d angles in the azimuth axis direction to find an azimuth capable of receiving radio waves from the artificial satellite more strongly. Item 10. An antenna control method according to Item 9. Here, d is a positive real number. 11. The method according to claim 11, wherein the directional direction of the antenna is shifted by ± d degrees in the elevation axis direction to find a direction capable of receiving radio waves from the artificial satellite more strongly. The antenna control method according to claim 9. Here, d is a positive real number. 12. The apparatus according to claim 9, wherein d is a number larger than a maximum angle from a directional direction of the antenna in a beam area in which the antenna can receive radio waves from the artificial satellite. , 11.