JPH07154127A - Antenna directing device - Google Patents

Abstract

PURPOSE:To direct the antenna accurately in a direction of a satellite by providing a shake angle arithmetic section and a gimbaling error arithmetic section in the device and using an output signal of the gimbaling error arithmetic section to eliminate a gimbaling error from a stern azimuth angle. CONSTITUTION:A shake angle arithmetic section 94 receives a signal indicating a tilt correction value DELTAphiA outputted from a tilt correction arithmetic section 93, a signal indicating a rotary angle theta of an antenna 14 outputted from an elevating angle oscillator 34, and a signal indicating a satellite altitude angle phiS Then shake angles eta, xsi of a mount side of a ship to which the antenna direction device is fitted are calculated. A gimbaling error arithmetic section 108 receives a signal indicating the shake angles eta, xsi and a signal indicating a satellite azimuth angle phiS to obtain a gimbaling error delta and it is fed to an adder 61 as a correction value DELTAphiC=delta. Then an error included in a stern azimuth angle phiC fed to a gyro compass or the like is eliminated thereby.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna directing device for directing an antenna suitable for use in maritime satellite communications or the like toward a satellite.

[0002]

2. Description of the Related Art FIG. 3 shows an example of a conventional antenna pointing device. This antenna pointing device is basically referred to as an azimuth-elevation system, and has a base 3 and an azimuth gimbal 40 attached to the base 3, and a mounting bracket attached to a U-shaped member at the upper end of the azimuth gimbal 40. 41 and the antenna 14 attached to such a mounting bracket 41.

The base 3 may have a bridge portion 3-1.
The bridge portion 3-1 has a cylindrical portion 11 protruding upward.
Is mounted, and a pair of bearings 21-1 and 21-2 is mounted inside the cylindrical portion 11. The azimuth axis 20 is fitted to the inner rings of the bearings 21-1 and 21-2, and the azimuth gimbal 40 is attached to the upper end of the azimuth axis 20 via the arm 13.

Thus, the azimuth axis 20 has the bearings 21-1, 21.
The azimuth gimbal 40 can rotate about an axis passing through the azimuth axis 20 while being supported by -2. The azimuth gimbal 40 has a lower support shaft portion 40-1 and an upper U-shaped portion 40-2, and the central axis of the support shaft portion 40-1, that is, the azimuth axis ZZ is as shown in the figure. It is arranged deviated from the axis passing through. The support shaft portion 40-1 may be configured to be aligned with the axis line passing through the azimuth axis 20.

On the U-shaped portion 40-2 of the orientation gimbal 40, a smaller U-shaped mounting member 41 is arranged, and the mounting member 41 has two legs 41-
The elevation angle axes 30-1 and 30-2 are provided on the respective 1 and 41-2. A suitable bearing is mounted on each of the two legs of the U-shaped portion 40-2 of the orientation gimbal 40, and the elevation shafts 30-1 and 30-2 are rotatably supported by the bearings.

The central axes of the elevation axes 30-1 and 30-2 form an elevation axis YY, and thus the mounting bracket 41 is located between the two legs of the U-shaped portion 40-2 of the orientation gimbal 40. Is rotatably supported around the elevation axis Y-Y. The elevation axis Y-Y is arranged at right angles to the azimuth axis Z-Z.

The azimuth axis ZZ is perpendicular to the mounting surface of the antenna directing device, for example the hull surface, so that the elevation axis YY is always arranged parallel to the hull surface.

The leg portion 41 of the U-shaped mounting bracket 41
The antenna 14 is attached to the antennas 1 and 41-2.
It can rotate around Y. The antenna 14 has a central axis XX, which is the elevation axis Y-.
It is perpendicular to Y.

The mounting bracket 41 includes an elevation gyro 44.
And the azimuth gyro 45 are attached, and the rotation angular velocity of the antenna 14 rotating around the elevation axis YY is detected by the elevation gyro 44, and both the elevation axis YY and the center axis XX of the antenna 14 are detected by the azimuth gyro 45. The angular velocity of rotation of the antenna 14 around the axis orthogonal to is detected. The elevation gyro 44 and the azimuth gyro 45 may be, for example, an integral gyro such as a mechanical gyro or an optical gyro, or an angular velocity detection gyro such as a vibration gyro, a rate gyro, or an optical fiber gyro.

A first accelerometer 46, a second accelerometer 47, and a third accelerometer 48 are further mounted on the mounting bracket 41. The first accelerometer 46 detects the inclination angle of the central axis XX of the antenna 14 around the elevation axis YY, and the second accelerometer 47 detects the inclination angle x of the elevation axis YY with respect to the horizontal plane. It

If the second accelerometer 47 is mounted on the mounting bracket 41 so that its input axis is parallel to the elevation axis YY, its output is proportional to sinx. The second accelerometer 47 may be attached to the azimuth gimbal 40 so that its input axis is parallel to the elevation axis YY.

The third accelerometer 48 is the first accelerometer 46.
And the second accelerometer 47 are mounted so as to be orthogonal to each other, that is, to have an input axis line that is orthogonal to both the input axis line of the first accelerometer 46 and the input axis line of the second accelerometer 47. It is attached. Thus, the third accelerometer 48 has the central axis XX and the elevation axis Y- of the antenna 14.
The tilt angle of the axis line orthogonal to both Y with respect to the horizontal plane is detected.

An elevation gear 32 is mounted on one leg of the mounting bracket 41 coaxially with the elevation axis Y--Y. A pinion 35 is meshed with the elevation gear 32, and the pinion 35 is mounted on one leg of the U-shaped portion 40-2 of the azimuth gimbal 40.
It is attached to the rotating shaft of 3.

An elevation transmitter 34 is attached to one leg of the U-shaped portion 40-2 of the azimuth gimbal 40, and the elevation transmitter 34 mounts the elevation axis Y--Y of the antenna 14.
A rotation angle θ around the rotation angle is detected and a signal indicating the rotation angle θ is output.

On the other hand, the azimuth gear 2 is provided at the lower end of the azimuth axis 20.
2 is attached, and the azimuth servo motor 23 and the azimuth transmitter 24 are attached on the bridge portion 3-1 of the base 3.
Pinions (not shown) attached to the rotating shafts of the azimuth servo motor 23 and the azimuth transmitter 24 are configured to mesh with the azimuth gear 22.

As shown, an elevation control loop and an azimuth control loop are provided to control the antenna pointing device. The angle formed by the central axis line XX of the antenna 14 with the horizontal plane is the elevation angle θ _A of the antenna, and the angle formed by the central axis line XX of the antenna 14 with the meridian line N on the horizontal plane is the azimuth angle φ _{A of the} antenna.

The elevation control loop is configured to rotate the antenna 14 about the elevation axis Y--Y so that the elevation angle θ _A of the antenna matches the satellite elevation angle θ _S , a fast control loop, namely elevation stabilization. A loop and a slow control loop, ie an elevation constraint loop. Fast control loop, ie
In the elevation angle stabilization loop, the output of the elevation angle gyro 44 is transmitted through the integrator 54 and the amplifier 55 to the elevation angle servo motor 3
It is fed back to 3. As a result, even if the hull oscillates, the angular velocity about the elevation axis YY of the antenna 14 with respect to the inertial space is always maintained at zero.

In the slow control loop, that is, the elevation angle restraint loop, the output signal of the orthogonal three-axis accelerometer consisting of the first accelerometer 46, the second accelerometer 47 and the third accelerometer 48 is the antenna elevation angle calculator. 81. The antenna elevation angle calculation unit 81 inputs the output signals of the three accelerometers 46, 47, 48, and receives the elevation angle θ _A of the antenna 14, that is, the inclination angle θ _A of the central axis XX of the antenna 14 with respect to the horizontal plane.
Is calculated.

Such calculation includes performing arctangent calculation from the tangent of the elevation angle θ _A of the antenna 14 to obtain the value of the elevation angle θ _A of the antenna 14 and its quadrant. For details of the function and configuration of the antenna elevation angle calculation unit 81, refer to Japanese Patent Application No. 4-348745 filed by the same applicant as the present applicant.

The signal indicating the elevation angle θ _A of the antenna 14 output from the antenna elevation angle calculation unit 81 is reduced by, for example, the signal indicating the manually set satellite altitude angle θ _S , and further passed through the attenuator 56. It is then input to the integrator 54 and the amplifier 55. This loop has a suitable time constant for matching the elevation angle θ _A of the antenna 14 to the satellite elevation angle θ _S. It should be noted that the attenuator 56 may be provided with an integral characteristic in order to compensate the drift fluctuation of the elevation angle gyro 44.

The azimuth control loop controls the azimuth gimbal 4 so that the azimuth φ _A of the antenna 14 matches the satellite azimuth φ _S.
It is configured to control zero azimuth and includes a fast control loop, an azimuth stabilization loop and a slow control loop, an azimuth constraint loop.

In a fast control loop, ie the azimuth stabilization loop, the output signal of the azimuth gyro 45 is the integrator 5
8 and the feedback to the azimuth servomotor 23 via the amplifier 59, which causes the antenna 14 to respond to the rotational movement of the hull about an axis orthogonal to both the central axis XX and the elevation axis YY of the antenna 14. Can be stabilized.

In the slow control loop, that is, in the azimuth angle constraining loop, the azimuth oscillator 24 outputs a rotation angle signal indicating the rotation angle φ of the azimuth gimbal 40 (rotation angle of the antenna), and the rotation angle signals are added. Is supplied to the container 61. In the adder 61, the rotation angle φ, the bow azimuth angle φ _C supplied from, for example, a magnetic compass or a gyro compass, and the tilt correction value Δφ _A supplied from the tilt correction calculation unit 93 are added, and the satellite is calculated from the sum. The azimuth angle φ _S is subtracted. The output signal of the adder 61 is further input to the integrator 58 via the attenuator 60. When the sum of the antenna rotation angle φ, the bow azimuth angle φ _C and the tilt correction value Δφ _A is equal to the satellite azimuth angle φ _S , the azimuth of the antenna 14 is stationary.

The tilt correction calculation unit 93 is used for the elevation transmitter 3.
4 outputs a signal indicating the rotation angle θ of the antenna 14 about the elevation axis YY and a sine value sinx of the inclination angle x of the elevation axis YY with respect to the horizontal plane output from the second accelerometer 47. Signal and the central axis line XX and the elevation axis line YY of the antenna output from the third accelerometer 48.
Enter a signal indicating the sine value sin [theta _P inclination angle theta _P with respect to the horizontal plane of the axis perpendicular to both of, it calculates a tilt correction value [Delta] [phi _A.

The tilt correction value Δφ _A is obtained by the following equation (1).

[0026]

## EQU1 ## tan Δφ _A = sin θ · sinx / sin θ _P

For the details of the construction and operation of the inclination correction calculation unit 93, refer to Japanese Patent Application No. 5-2581 filed by the same applicant as the present applicant.

The azimuth control loop has an appropriate time constant for matching the azimuth angle φ _A of the antenna 14 with the satellite azimuth angle φ _S. Incidentally, the attenuator 60 may be provided with an integral characteristic in order to compensate for the drift fluctuation of the azimuth gyro 45. That is, the outputs of the attenuators 56 and 60 correspond to the output of the integral gyro torquer.

In this way, the antenna 14 is constructed so that its central axis XX is directed toward the satellite by the elevation angle control loop and the azimuth angle control loop.

[0030]

However, in the conventional antenna directing device, the bow azimuth angle φ _C supplied to the adder 61 is obtained from, for example, a gyro compass or a magnetic compass. Since these gyro compass and magnetic compass have a gimbal mechanism inside, they have an output error called a gimbaling error due to the motion or static inclination of the hull.

A mechanism for generating a gimbaling error in the gyro compass will be described with reference to FIG. Consider a unit spherical surface having a radius of 1, and let the center of the unit spherical surface be O. It is assumed that the bow of the hull faces the true north direction ON (spin axis direction), and when the hull surface is in the horizontal plane, points where the roll axis and the pitch axis intersect the unit spherical surface are points F and B, respectively.

Next, it is assumed that the hull oscillates and is rotated and tilted around the rotation axis (tilt axis) of the hull surface. A point at which the rotation axis (tilt axis) intersects the unit spherical surface is defined as A. It is assumed that the rotation axis (tilt axis) OA of the hull surface is offset by the azimuth angle γ with respect to the true north direction ON. That is, arc AF
= Γ. When the hull surface rotates about the rotation axis (tilt axis) OA by the rotation angle ε, points where the unit spherical surface intersects the roll axis and the pitch axis are defined as points F ″ and B ″, respectively.

When the hull surface rotates about the rotation axis OA by the rotation angle ε, the follower axis OZ rotates by the rotation angle ε and moves to OZ ', and the roll axis OF moves to OF ". A point intersecting the sphere draws an arc FF ″ having a radius γ. Arc AF = arc AF ″ = γ.

The baseline of the compass card does not move from point F to point F'along the meridian, but from point F to point F "along arc FF". Therefore, the gyro compass outputs an angle δ corresponding to the arc F′F ″ = δ, which is a gimbaling error in the gyro compass.

Applying the spherical trigonometry to the spherical triangle ΔAFF ',

[0036]

## EQU2 ## tan (γ + δ) = tan γ / cos ε

If this is solved for δ,

[0038]

[Equation 3]

This is an expression for obtaining a gimbaling error in the gyro compass.

Next, with reference to FIGS. 5 and 6, the mechanism of occurrence of a gimbaling error in the magnetic compass will be described. As shown in FIG. 5, the magnetic compass is attached to the roll gimbal ring 121, and the roll gimbal ring 121 is supported by the support members 123, 1 so as to be parallel to the hull surface.
It is attached to 23. The roll gimbal ring 121 is rotatably mounted around a rotation axis line along the heading direction, that is, the roll axis line RR, and the magnetic compass is rotatably mounted around a rotation axis line orthogonal to the heading direction, that is, around the pitch axis line P-P. Has been done.

In the magnetic compass, the repeater 125 is arranged below the roll gimbal ring 121, and its center of gravity is below the two rotation axes. In this way, repeater 1
25 forms a physical pendulum that rotates about two rotation axes. Therefore, the pitch axis P-P is always maintained in the horizontal plane.

A mechanism for generating a gimbaling error will be described with reference to FIG. As in the case of FIG. 4, a unit spherical surface having a radius of 1 is considered, and the center of the unit spherical surface is set to O. When the roll gimbal ring is in the horizontal plane, the points where the roll axis R-R and the pitch axis P-P intersect the unit spherical surface are point F,
Let B.

Next, it is assumed that the hull oscillates and is rotated and tilted around the rotation axis (tilt axis) of the hull surface. A point at which the rotation axis (tilt axis) intersects the unit spherical surface is defined as A. It is assumed that the rotation axis (tilt axis) OA of the hull surface is offset by the azimuth angle γ with respect to the bow orientation OF.

When the hull surface rotates about the rotation axis (tilt axis) OA by the rotation angle ε, the roll axis OF moves to OF '. The pitch axis OB also moves to OB ″, but since the magnetic compass constitutes the physical pendulum with the center of gravity downward as described above, the pitch axis is always in the horizontal plane, and thus the pitch axis OB ″ is in the horizontal plane. Where ∠F'OB ”=
∠FOB = 90 °. Also, ∠F'OA = ∠FOA =
γ = arc F′A = arc FA.

The distance BB '= δ at which the point B where the pitch axis OB intersects the unit spherical surface moves along the equator is the gimbaling error.

Applying the spherical trigonometry to the spherical triangle ΔFF'B ",

[0047]

Tan (γ−δ) = tan γ · cos ε

If this is solved for δ,

[0049]

[Equation 5]

This is an equation for obtaining the gimbaling error in the magnetic compass.

The following expression is obtained by Taylor expansion of the expression of the expression 3 and the expression of the expression 5.

[0052]

[Equation 6] δ ≒ (1/4) sin2γ ・ ε ²

As is clear from the equation (6), the gimbaling error δ takes the maximum value when the deviation angle γ of the inclination axis (rotation axis) OA of the hull surface is γ = 45 °, 135 °, 225 °, etc. Moreover, it is proportional to the square of the inclination angle ε of the hull surface.

For example, when γ = 45 ° and ε = 25 °,
The gimbaling error is δ = 2.73 °. That is, the bow azimuth angle φ _C includes an error of 2.73 °.

Therefore, in the conventional antenna pointing device, an error occurs in the control signal in the fourth control loop due to the gimbaling error, and the central axis line XX of the antenna 14 is generated.
Had a drawback that it was deviated from the satellite direction, which should be the original direction.

In view of the above point, the present invention is designed so that the antenna 1 is always operated even when the hull sways or statically leans during navigation.
It is an object of the present invention to provide an antenna directing device capable of favorably directing 4 to a satellite.

[0057]

According to the present invention, a support member 41 having a central axis XX, as shown in FIG.
The azimuth gimbal 40 that rotatably supports the antenna 14 supported on the antenna 14 and the supporting member 41 around the elevation axis YY orthogonal to the central axis XX, and the azimuth gimbal 40 on the elevation axis YY. A base 3 rotatably supporting the azimuth axis ZZ orthogonal to each other, a first gyro 44 having an input axis parallel to the elevation axis Y-Y and fixed to the support member 41, and a central axis X-. A second fixed to the support member 41 having an input axis orthogonal to both X and the elevation axis Y-Y.
Gyro 45, and a first accelerometer 46 that outputs a signal indicating the tilt angle of the central axis line XX with respect to the horizontal plane,
A second accelerometer 47 that outputs a signal that indicates the tilt angle of the elevation axis YY with respect to the horizontal plane, and a third accelerometer 47 that has an input axis orthogonal to both the center axis XX of the antenna and the elevation axis YY. The accelerometer 48, the azimuth oscillator 24 that outputs a signal indicating the rotation angle of the azimuth gimbal 40 about the azimuth axis ZZ, and the elevation axis YY with respect to the azimuth gimbal 40.
An elevation angle oscillator 34 that outputs a signal indicating the rotation angle θ of the surrounding antenna 14, an output signal of the second accelerometer 47, an output signal of the third accelerometer 48, and an output signal of the elevation angle oscillator 34. And a tilt correction calculation unit 93 that calculates a tilt correction value Δφ _A by inputting a signal obtained by subtracting a value corresponding to the altitude angle of the satellite from the output signals of the accelerometers 46, 47 and 48 in the first gyro. The output signal of the azimuth transmitter 24, the signal corresponding to the heading azimuth angle and the satellite azimuth angle, and the signal indicating the tilt correction value Δφ _A output from the tilt correction calculation unit 93 are added to the substantial torquer 44. In the antenna directing device configured to perform the calculation by the device 61 and feed back the output signal to the substantial torquer of the second gyro 45 to direct the central axis XX of the antenna to the satellite, the tilt correction calculating unit. 9 More supplied tilted correction value Δφ
_A , a satellite altitude angle θ _S , a rotation angle θ of the antenna about the elevation axis Y-Y supplied from the elevation transmitter 34, and a swing angle calculation unit 94 that calculates the swing angle of the mounting surface of the antenna pointing device, The fluctuation angles η, ξ supplied from the angle calculation unit 94
And a satellite azimuth angle φ _A and a gimbaling error calculation unit 108 that calculates a gimbaling error δ = Δφ _C that occurs in the bow azimuth angle φ _C.
The output signal of 08 is used to remove the gimbaling error δ = Δφ _C from the bow azimuth φ _C.

According to the present invention, in the antenna directing device, the swing angle calculating unit 94 calculates the swing angles η and ξ of the mounting surface of the antenna directing device by the following equation. η = tan ⁻¹ (sin Δφ _A / tan θ) θ _S −ξ = tan ⁻¹ (tan Δφ _A / sin η) where η and ξ are the shaking angles of the mounting surface Δφ _A : the tilt correction value θ: the output signal of the elevation transmitter θ _S : Satellite altitude angle

According to the present invention, in the antenna pointing device, when the bow azimuth angle φ _C is obtained by the gyro compass, the gimbaling error calculation unit 108 calculates the gimbaling error δ included in the bow azimuth angle φ _C by the following equation. Calculate However, δ: Gimbaling error included in the bow azimuth φ _C ε: Tilt angle around the inclination axis (rotation axis) of the hull surface γ: Azimuth angle of the inclination axis (rotation axis) of the hull surface with respect to the true north direction Φ: Azimuth of the tilt axis (rotation axis) of the hull surface with respect to the bow direction

According to the present invention, in the antenna pointing device, when the bow azimuth φ _C is obtained by the magnetic compass, the gimbaling error calculator 108 calculates the gimbaling error δ included in the bow azimuth φ _C by the following equation. Calculate

[0061]

However, δ: a gimbaling error included in the heading azimuth angle φ _C ε _M : an inclination angle around the inclination axis (rotation axis) of the hull surface γ _M : an inclination axis of the hull surface with respect to the bow direction (rotation axis)
Azimuth angle φ _S : Satellite azimuth angle φ _C : Bow azimuth angle ξ _A η _A : Ship hull angle in antenna reference system

[0063]

According to the present invention, the sway angles η and ξ are calculated by the sway angle calculation unit 94 by the formula 8 and the gimbaling error calculation unit 108 calculates the formulas 10, 12 and 13. The gimbaling error δ is obtained by the formula 14 or the formula 15 and the heading φ _C
Since the correction value Δφ _C = δ is supplied to the adder 61, the control signal output from the adder 61 has the influence of the gimbaling error δ removed. Therefore, in the fourth control loop, even if the hull sways, the central axis X- of the antenna 14 is not affected by the gimbaling error δ.
X can be accurately directed to the satellite.

[0064]

Embodiments of the present invention will be described below with reference to FIGS. 1 to 2, corresponding parts in FIG. 3 are designated by the same reference numerals, and detailed description thereof will be omitted.

FIG. 1 shows an example of an antenna directing device of the present invention. The antenna directing device is a base 3 and such a base 3.
The azimuth gimbal 40 mounted on the azimuth gimbal 40, the mounting bracket 41 mounted on the U-shaped member at the upper end of the azimuth gimbal 40, and the antenna 14 mounted on the mounting bracket 41.

The antenna 14 has a central axis line XX, and the assembly consisting of the antenna 14 and the mounting bracket 41 attached to the antenna 14 has an elevation axis line YY which is orthogonal to the central axis line XX. It is rotatably supported around. The azimuth gimbal 40 is supported by the base 3 so as to be rotatable about an azimuth axis ZZ orthogonal to the elevation axis YY.
In this way, a support mechanism rotatable about two axes is configured, and such a support mechanism is controlled so that the central axis line XX of the antenna 14 points the satellite.

The mounting bracket 41 includes an elevation gyro 44.
Further, an azimuth gyro 45, a first accelerometer 46, a second accelerometer 47 and a third accelerometer 48 are attached.

By the elevation gyro 44, the elevation axis YY
The angular velocity of rotation of the antenna 14 rotating around is detected,
The azimuth gyro 45 detects the rotational angular velocity of the antenna 14 around an axis orthogonal to both the elevation axis YY and the center axis XX of the antenna 14, and the first accelerometer 46.
The central axis line XX of the antenna 14 with respect to the horizontal plane
Is detected, and the second accelerometer 47 detects the inclination angle of the elevation axis YY with respect to the horizontal plane.

The third accelerometer 48 is the first accelerometer 46.
Of the second accelerometer 47 and the input axis of the second accelerometer 47 are orthogonal to each other. Therefore, the third accelerometer 48 has a central axis X− of the antenna 14.
The tilt angle of the axis line orthogonal to both X and the elevation axis line Y-Y with respect to the horizontal plane is detected.

The elevation angle gyro 44 and the azimuth gyro 45 may be angular velocity detection type gyros such as a vibration gyro and a rate gyro.

The antenna directing apparatus of this example has an elevation angle control loop and an azimuth angle control loop as in the conventional example of FIG. The elevation angle control loop of this example sets the antenna 14 so that the elevation angle θ _A of the antenna matches the satellite elevation angle θ _S.
It is configured to rotate around -Y and may be the same as a conventional elevation control loop.

The azimuth control loop of this example is designed so that the azimuth φ _A of the antenna matches the azimuth φ _{S of the} satellite.
4 is configured to rotate around the azimuth axis Z-Z, and differs from the conventional azimuth angle control loop in that a swing angle calculation unit 94 and a gimbaling error calculation unit 108 are newly provided. . That is, in the conventional fourth loop, in addition to the tilt correction calculation unit 93, a swing angle calculation unit 94 and a gimbaling error calculation unit 108 are newly provided, and the output signal of the gimbaling error calculation unit 108 is an adder. 6
1 is supplied.

The sway angle calculation unit 94 calculates the signal indicating the tilt correction value Δφ _A output from the tilt correction calculation unit 93 and the rotation angle θ of the antenna 14 about the elevation axis YY output from the elevation transmitter 34. A signal for instructing and a signal for instructing the satellite altitude angle θ _S are input, and the sway angles η and ξ of the mounting surface of the hull on which the antenna directing device is mounted are calculated.

The gimbaling error calculation unit 108 inputs the signals indicating the fluctuation angles η and ξ and the signal indicating the satellite azimuth angle φ _S output from the fluctuation angle calculation unit 94, and determines the gimbaling error δ, Correct it for the bow azimuth angle Δφ _C
And supplies it to the adder 61 as δ.

The functions and operations of the swing angle calculating section 94 and the gimbaling error calculating section 108 of this example will be described with reference to FIG. 2 considers a unit spherical surface having a radius of 1, and considers the unit spherical surface and the central axis line XX of the antenna 14 (the line segment O in FIG.
X), elevation axis line Y-Y (segments OY and OY 'in FIG. 2),
Azimuth axis line ZZ (line segments OZ and OZ 'in FIG. 2) and an axis line orthogonal to both the center axis line XX of the antenna 14 and the elevation axis line YY (line segments OP and OP' in FIG. 2). ), Of FIG.

The azimuth axis ZZ is always perpendicular to the hull surface (the mounting surface of the antenna directing device), and the elevation axis YY is always parallel to the hull surface.

Consider a case where the hull rotates about the first rotation axis by the rotation angle (sway angle) ξ and further rotates about the second rotation axis by the rotation angle (sway angle) η. Due to such a rotational movement of the hull, for example, as shown in the figure, the hull surface is rotated about the elevation axis YY (OY) with respect to the horizontal plane by a rotation angle ξ.
It is assumed that the vehicle has rotated by a rotation angle η, and further has rotated by a rotation angle η around the hull OE line. At this time, the elevation axis YY is the first
Is parallel to the axis of rotation of the ship, and the hull's tail line OE is parallel to the second axis of rotation.

By the movement of the hull surface, the azimuth axis Z
-Z moves from line OZ to line OZ 'and elevation axis Y-Y moves from line OY to line OD. Incidentally, ∠XOD = 90 °. The central axis XX of the antenna 14 also moves, but the central axis XX of the antenna 14 is controlled by the control loop so as to point in the satellite direction. That is, the antenna 14
The central axis line X-X of is moved to a position deviated from the line OX and again moved to the line OX.

By such control, the elevation axis Y-Y rotates about the azimuth axis OZ 'by the rotation angle Δφ _A and moves from the line OD to the line OY'. Incidentally, ∠XOY '= 90 °.
In addition, the central axis line XX of the antenna 14 and the elevation axis line YY
The line OP orthogonal to both of these moves to the line OP '. Eventually, the line OY has moved to the line OY 'via the line OD, and ∠POP' = ∠Y'OY and arc PP '= arc Y'.
It is Y.

The line OX, the line OY, and the line OP are lines of length 1 which are orthogonal to each other, and the triangle XYP is an equilateral spherical triangle with one side of π / 2. The line OX, the line OY ', and the line OP' are also lines of length 1 orthogonal to each other, and the triangle XY'P 'is an equilateral spherical triangle with one side of π / 2. A point X is connected to a point P and a point P ′ by a straight line on the unit spherical surface. The arc XP is orthogonal to the horizontal plane at the point A and further orthogonal to the plane OY'P 'at the point P. The arc XP ′ is orthogonal to the hull surface (mounting surface) at the point C, and is further orthogonal to the surface OY′P ′ at the point P ′. The foot of the perpendicular line drawn from the point P ′ to the horizontal plane is A ′, and the foot of the perpendicular line drawn from the point Y ′ to the horizontal plane is B ′.

Here, ∠XOA = θ ₀ = arc XA, ∠PO
A = θ _P0 = arc PA, ∠BOD = η = arc BD, ∠XOC =
θ = arc XC, ∠P'OA '= θ _P = arc P'A', ∠Y '
OB '= x = arc Y'B'.

The first accelerometer 46 is mounted along the line OX, and the second accelerometer 47 is mounted along the line OY.
The third accelerometer 48 is mounted along the line OP.
When the ship surface is the same as the horizontal surface, the elevation angle transmitter 34 outputs the inclination angle ∠XOA = θ ₀ of the central axis line XX of the antenna 14 with respect to the ship surface, and the first accelerometer 46 outputs sin∠XOA = sin θ. ₀ is detected, the second accelerometer 47 detects sin∠YOB = sin0 = 0, and the third accelerometer 48 detects sin∠POA.
= Sin θ _P0 is detected.

As described above, when the hull surface rotates about the elevation axis YY (OY) with respect to the horizontal plane by the rotation angle ξ, and further around the tail line OE by the rotation angle η,
The elevation angle transmitter 34 outputs the inclination angle ∠XOC = θ of the central axis XX of the antenna 14 with respect to the hull surface, and the first angle
Sin ∠XOA = sin θ ₀ is detected by the accelerometer 46 of the above, and sin ∠Y′O is detected by the second accelerometer 47.
B ′ = sinx is detected, and the third accelerometer 48 detects sin∠P′OA ′ = sin θ _P. First
Value detected by accelerometer 46 of sin∠XOA =
sin θ ₀ does not change because the satellite altitude angle θ _S (= θ
_A. ) Is unrelated to the motion of the hull surface.

Next, the relationship between the tilt correction value Δφ _A and the shaking angles η and ξ will be determined. Tilt correction value Δφ _A = arc EC = arc D
Y '. The inclination correction value Δφ _A is, as described above,
It is obtained by the formula of Formula 1. By applying the spherical trigonometric theorem, the following equation 7 can be obtained.

[0085]

(7) sin Δφ _A = tan η · tan θ cos η = sin θ / sin (θ _S −ξ) cos Δφ _A · cos θ = cos (θ _S −ξ)

Here, η and ξ are swing angles, Δφ _A is a tilt correction value, and θ is a rotation angle of the antenna about the elevation axis Y-Y with respect to the azimuth gimbal 40. When the shaking angles η and ξ are obtained from the equation (7), the following equation (8) is obtained.

[0087]

Η = tan ⁻¹ (sin Δφ _A / tan θ) θ _S −ξ = tan ⁻¹ (tan Δφ _A / sin η)

According to this example, the swaying angle calculating section 94 executes the calculation of the equation (8) to obtain the swaying angles η and ξ. The signals indicating the swing angles η and ξ are supplied from the swing angle calculation unit 94 to the gimbaling error calculation unit 108.

The inclination correction value Δφ _A can be obtained as an output value of the inclination correction calculation section 93, but is preferably obtained as follows. The fourth loop is configured to control the azimuth of the azimuth gimbal 40 so that the output of the adder 61 becomes zero. Therefore, when the output of the adder 61 is zero, the following equation 9 is used. Is established.

[0090]

[Equation 9] Δφ _A = φ _S −φ _C −φ

Here, φ _S is the satellite azimuth angle, φ _C is the bow azimuth angle, and φ is the rotation angle of the azimuth gimbal 40 output by the azimuth oscillator 24. Each term on the right side of the equation (9) can be obtained as a value that is not directly affected by the shaking acceleration or a value that is less affected by the shaking acceleration.
Therefore, the inclination correction value Δφ _A may be obtained by using the formula of Expression 9 instead of using the output value of the inclination correction calculation unit 93.

As described above, the gimbaling error calculation unit 108 obtains the fluctuation angles η and ξ obtained from the fluctuation angle calculation unit 94.
And a heading azimuth angle φ _C are used to calculate a gimbaling error δ, which is output as a correction value Δφ _C = δ for the bow azimuth angle φ _C.

The value of the gimbaling error δ in the gyro compass and the magnetic compass was obtained with reference to FIGS. 4 to 6, but here with reference to FIG.

First, the gimbaling error δ in the gyro compass is obtained. In FIG. 2, the bow of the hull is oriented in the true north direction ON (spin axis direction), and when the hull surface (mounting surface) is on the horizontal plane, the points where the roll axis and the pitch axis intersect the unit spherical surface, respectively. F and B. That is, the point F is the intersection of the meridian and the equator.

The hull surface is an elevation axis YY with respect to the horizontal plane.
It is assumed that it has rotated about (OY) by the rotation angle ξ and further about the hull's tail line OE by the rotation angle η. The point where the roll axis intersects the unit circle is F ″, the intersection of the hull surface and the meridian is F ′, and the intersection of the hull surface and the equator is G.
Such a rotational movement causes the hull surface to have a rotation angle ε about the rotation axis OG.
It is equivalent to rotating only. The angle formed by the rotation axis OG of the hull surface and the heading (ON) is γ.

Arc GF = arc GF ″ = γ. Arc F′F ″ is the gimbaling error δ in the gyro compass. That is, the arc F′F ″ = δ = Δφ _C.

Applying the spherical trigonometry to the spherical triangle ΔGFF ′,

[0098]

[Equation 10]

Applying the spherical trigonometry to the spherical triangle ΔEGA, the arc AG = Φ

[0100]

[Equation 11]

Here, since γ = φ _S + Φ,

[0102]

[Equation 12]

On the other hand, the following equation holds.

[0104]

[Equation 13] cos ε = cos η · cos ξ

From the equations (10), (12) and (13), the gimbaling error δ = in the gyro compass is obtained.
Δφ _C can be obtained.

Similarly, a gimbaling error δ = Δφ _C in the magnetic compass is obtained. The following formula is obtained by the spherical trigonometry.

[0107]

[Equation 14]

Here, tan γ _M and cos ε _M are expressed by the following equations.

[0109]

[Equation 15]

Here, φ _S : satellite azimuth φ _C : bow azimuth ξ _A η _A : ship hull angle in the antenna reference system

A gimbaling error δ = Δφ _C in the magnetic compass can be obtained from the equations (14) and (15).

The gimbaling error δ is calculated by the gimbaling error calculation unit 108, and the correction value Δφ _C = δ of the bow azimuth angle φ _C is calculated by the gimbaling error calculation unit 108.
Is output to the adder 61. As a result, the heading azimuth φ _C supplied by the gyro compass or magnetic compass
The error contained in is removed. Therefore, in the fourth control loop, an accurate control signal containing no error is obtained, so that the central axis line XX of the antenna 14 can be accurately directed in the satellite direction.

Some gyro compasses do not generate the above-mentioned gimbaling error δ. The present invention is applied when the bow azimuth angle φ _C includes a gimbaling error δ.

Although the embodiments of the present invention have been described in detail above, those skilled in the art will understand that the present invention is not limited to the above-mentioned embodiments and various other configurations can be adopted without departing from the gist of the present invention. Easy to understand.

[0115]

According to the present invention, the swaying angles η and ξ are obtained by the swaying angle calculating section 94 by the equation (8), and the swaying error calculating section 108 calculates the equations (10) and (12).
Since the gimbaling error δ when the gyro compass is used can be obtained by the equation of Eq. 13 and the equation of Eq. 13, the accurate bow azimuth φ _C that is not affected by the gimbaling error δ
There is an advantage that can be obtained.

According to the present invention, the swaying angles η and ξ are calculated by the swaying angle calculating unit 94 by the formula 8 and the gimbaling error calculating unit 108 calculates the formulas 14 and 15.
Since the gimbaling error δ when the magnetic compass is used is obtained by the equation, there is an advantage that an accurate bow azimuth φ _C that is not affected by the gimbaling error δ can be obtained.

According to the present invention, the sway angles η and ξ are obtained by the sway angle calculation unit 94 by the formula 8 and the gimbaling error calculation unit 108 calculates the formulas 10, 12 and 13. The gimbaling error δ when a gyro compass is used is calculated by
_Since the correction value Δφ _C = δ of _C is output to the adder 61,
The adder 61 has the advantage of outputting an accurate control signal that is not affected by the gimbaling error δ.

According to the present invention, the sway angles η and ξ are calculated by the sway angle calculation unit 94 by the formula 8 and the gimbaling error calculation unit 108 calculates the formulas 14 and 15.
Formula gimballing error δ when using magnetic compass is determined by the correction value [Delta] [phi _C of heading angle phi _C
Since = δ is output to the adder 61, there is an advantage that the adder 61 outputs an accurate control signal that is not affected by the gimbaling error δ.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of an antenna pointing device of the present invention.

FIG. 2 is an explanatory diagram illustrating an operation of an antenna directing device on a unit spherical surface.

FIG. 3 is a diagram showing an example of a conventional antenna directing device.

FIG. 4 is an explanatory diagram illustrating a mechanism of a gimbaling error in a gyro compass.

FIG. 5 is an explanatory diagram illustrating a mechanism of occurrence of a gimbaling error in the magnetic compass.

FIG. 6 is an explanatory diagram illustrating a mechanism of occurrence of a gimbaling error in the magnetic compass.

[Explanation of symbols]

 3 pedestal 3-1 bridge part 11 cylindrical part 13 arm 14 antenna 20 azimuth axis 21-1, 21-2 bearing 22 azimuth gear 23 azimuth servo motor 24 azimuth transmitter 30-1, 30-2 elevation angle shaft 32 elevation angle gear 33 Elevation servo motor 34 Elevation transmitter 35 Pinion 40 Azimuth gimbal 40-1 Support shaft part 40-2 U-shaped part 41 Mounting brackets 41-1, 41-2 Legs 44 Elevation gyro 45 Azimuth gyro 46 First accelerometer 47 No. 2 accelerometer 48 third accelerometer 54 integrator 55 amplifier 56 attenuator 58 integrator 59 amplifier 60 attenuator 61 adder 81 antenna elevation angle calculator 93 tilt correction calculator 94 wobble angle calculator 108 gimbaling error calculator 121 Roll Gimbal Ring 123 Support Member 125 Repeater XX Antenna Center Axis YY elevation axis ZZ azimuth axis

Claims (4)

[Claims] 1. An antenna having a central axis and supported by a supporting member, an azimuth gimbal for rotatably supporting the antenna and the supporting member about an elevation axis orthogonal to the central axis, and the azimuth gimbal. A pedestal rotatably supported around an azimuth axis orthogonal to the elevation axis, a first gyro having an input axis parallel to the elevation axis and fixed to the support member, and both the center axis and the elevation axis. A second gyro fixed to the support member having an input axis orthogonal to the first axis, a first accelerometer for outputting a signal indicating an inclination angle of the central axis with respect to the horizontal plane, and an inclination of the elevation axis with respect to the horizontal plane. A second accelerometer for outputting a signal indicating an angle; a third accelerometer having an input axis orthogonal to both the central axis of the antenna and the elevation axis; and the azimuth axis of the azimuth gimbal. The azimuth transmitter that outputs a signal that indicates a rotation angle around the line, the elevation angle transmitter that outputs a signal that indicates a rotation angle of the antenna about the elevation axis with respect to the azimuth gimbal, and the second accelerometer. And a tilt correction calculation unit for calculating a tilt correction value by inputting the output signal, the output signal of the third accelerometer and the output signal of the elevation angle transmitter, and calculating the tilt correction value from the output signal of the accelerometer of the satellite. The signal obtained by subtracting the value corresponding to the altitude angle is fed back to the substantial torquer of the first gyro, and the output signal of the azimuth transmitter, the signal corresponding to the heading azimuth angle and the satellite azimuth angle, and the tilt correction calculation unit. And a signal indicating the inclination correction value Δφ _A output by the adder is calculated, and the output signal is calculated as the second signal.
In the antenna directing device configured to feed back the substantial axis of the gyro to direct the central axis of the antenna to the satellite, the tilt correction value supplied from the tilt correction calculation unit, the satellite altitude angle, and A swing angle calculation unit for calculating the swing angle of the mounting surface of the antenna pointing device from the rotation angle of the antenna around the elevation angle axis supplied from the elevation transmitter, and the swing angle supplied from the swing angle calculation unit and the satellite. A gimbaling error calculator that calculates a gimbaling error that occurs in the azimuth and the bow azimuth is provided, and the gimbaling error is removed from the bow azimuth using the output signal of the gimbaling error calculator. An antenna pointing device characterized by being configured. 2. The antenna directing device according to claim 1, wherein the swing angle calculating section calculates a swing angle of a mounting surface of the antenna directing device according to the following equation. η = tan ⁻¹ (sin Δφ _A / tan θ) θ _S −ξ = tan ⁻¹ (tan Δφ _A / sin η) where η and ξ are the shaking angles of the mounting surface Δφ _A : the tilt correction value θ: the output signal of the elevation transmitter θ _S : Satellite altitude angle 3. The antenna pointing device according to claim 1, wherein when the bow azimuth φ _C is obtained by a gyro compass, the gimbaling error calculation unit includes a zimba included in the bow azimuth φ _{C according} to the following equation. An antenna pointing device characterized by calculating a ring error δ. δ: Gimbaling error included in the bow azimuth φ _C Φ: Azimuth of the tilt axis (rotation axis) of the hull surface with respect to the bow direction γ: Azimuth of the tilt axis (rotation axis) of the hull surface with respect to the true north direction ε: Inclination angle around the inclination axis (rotation axis) of the hull surface 4. The antenna pointing device according to claim 1, wherein when the bow azimuth angle φ _C is obtained by a magnetic compass, the gimbaling error computing unit includes a zimba included in the bow azimuth angle φ _{C according} to the following equation. Ring error δ
An antenna directing device, characterized in that: δ: Gimbaling error included in the heading azimuth φ _C γ _M : Inclination axis of the hull surface with respect to the bow direction (rotation axis)
Azimuth angle ε _M : Inclination angle around the inclination axis (rotation axis) of the hull surface φ _S : Satellite azimuth angle φ _C : Bow azimuth angle ξ _A η _A : Hull sway angle in the antenna reference system