RU2070757C1 - Pencil-beam antenna for communication with geostationary artificial earth satellite - Google Patents

Abstract

FIELD: antennas for communication with geostationary artificial earth satellites. SUBSTANCE: antenna positioner with polar suspension has its fixed axis 2 deflected towards equator from polar axis through angle equal to difference between depression angles in antenna guiding to geostationary orbit points lying in meridian plane and in plane perpendicular to it that crosses polar angle. EFFECT: improved design. 5 dwg, 1 tbl

Description

 The invention relates to the field of communication antennas with geostationary artificial Earth satellites (GSIS3), i.e. IS3 located in the geostationary orbit (GSO), more precisely to their slewing-rotary devices (OPU).

 Traditional GPCs are biaxial, have two axis of rotation of the antenna: stationary relative to the Earth and mobile, fixed on the first. This design provides the ability to point the antenna anywhere in the visible sky.

 The most common are elevation-azimuthal (alt-azimuthal) OPA, the fixed (azimuthal) axis of which is vertical, and the movable (elevation) axis attached to it is horizontal (see automatic certificate N 1612897, H 01 Q 1/00, 1989 )

 To observe celestial bodies, equatorial GPCs can be used, the fixed (polar) axis of which is directed to the visible pole of the world (parallel to the axis of rotation of the Earth, i.e., directed to the north and deviated from the horizontal by an angle Φ equal to the geographical latitude of the antenna's dislocation point), and the moving axis (declination axis) is perpendicular to the polar. Such an arrangement of the axes makes it possible to observe celestial bodies “not fixed” to the celestial sphere by rotating the antenna only around the polar axis, using the second axis only to point the antenna at the celestial body. (NN Mikhelson "Optical telescopes", Science, M. 1976, p. 337, 359).

 The closest technical solution is a highly directional communication antenna made using this scheme with geostationary artificial Earth satellites, containing a slewing ring with a fixed axis of rotation located in the Earth’s meridional plane (see. "Antenna for satellite television broadcasting. Models STV Luch-2.5 and STV Luch-3,5 ". Passport, 1991, p. 4).

Antennas with any type of GPC can be used for communication with the SSISE, as during communication, the antenna remains almost stationary; if necessary, only an insignificant, of the order of angular minutes, correction is made for tracking and drift of the SSISS. However, to reinstall the antenna from one SSISS to another, located at a remote point from the first GSO, it is necessary to rotate the antenna around two axes, and the angle of rotation around the movable axis with alt-azimuthal GPC is measured in several (up to 30 - 40 ^o ) degrees, and at equatorial by several tens of arc minutes. And in that, and in another case, the presence of two axes and antenna mechanisms is mandatory, because the required pointing accuracy ranges from fractions to several angular minutes, depending on the diameter of the antenna and the length of the working wave.

 What is new in the design of a highly directional antenna is that the fixed axis is set in the direction deviated toward the equator from the polar axis by an angle equal to the difference of the declination angles when pointing the antenna at the points of the geostationary orbit lying in the meridional plane and in the plane perpendicular to it passing through the polar axis.

 The technical result of the invention is the exclusion from the design of the movable axis of rotation of the antenna, which simplifies the rotary support device of the antenna and thereby its operation.

 In FIG. 1 shows an antenna in section along the plane of the angle of inclination of the fixed axis; figure 2 is a section of the Earth by the meridional plane in the antenna and GSO installed in the position on the south; figure 3 is a view along arrow K of figure 2; figure 4 section aa figure 2, the antenna is shown in the east position; figure 5 section BB (figure 3, rotated), the antenna is shown rotated in the plane of the section BB.

 A pointed antenna for communication with geostationary artificial Earth satellites contains a mirror 1 mounted on a rotary support device (OPU), including a fixed axis 2 (with a geometric axis E) mounted on a horizontal platform 3. The fixed axis 2 of the antenna is located in the meridional plane of the Earth (in vertical plane north-south), combined in figure 1 with the plane of the drawing, at an angle D towards the equator (in the northern hemisphere to the south) from the direction T to the visible pole of the world or, what is the same, towards the geographer of the polar pole (in the northern hemisphere to the north) at an angle F = Φ + Δ from the horizon, where v is the geographical latitude of the point O of the antenna dislocation, and D is the difference of the declination angles when the antenna is pointing to the geostationary orbit (GSO) in the eastern and southern directions.

OPU also includes a drive or mechanism 4 of rotation of the antenna around a fixed axis 2; a hinge 5 connecting the axis 2 and the platform 3 and a device (for example, a strut 6 of variable length) for mounting the axis 2 at an angle F _to the horizontal; hinge 7 and device 8 for mounting the focal axis F of the antenna at the required angle γ to axis E.

, а при направлении антенны на точку В (фиг.3,4) ГСО, расположенную на востоке (или западе) в плоскости, проходящей через полярную ось в точке дислокации антенны и перпендикулярной меридиональной плоскости Земли,

где r радиус Земли в точке дислокации антенны, а R радиус геостационарной орбиты.From the geometric constructions shown in FIGS. 2,3,4, it can be seen that the declination angle (the angle between the focal axis F of the antenna and the equatorial plane — the GSO plane) when the antenna is directed to the GSO point located in the south, i.e. in the meridional plane of the Earth (point Yu in figure 2,3), is equal to

and when the antenna is directed to point B (Fig. 3.4), a GSO located in the east (or west) in a plane passing through the polar axis at the antenna's dislocation point and perpendicular to the Earth’s meridional plane,

where r is the radius of the Earth at the point of dislocation of the antenna, and R is the radius of the geostationary orbit.

E-axis (axis 2) of the antenna installed at an angle to the polar axis Δ T equal to D = δ _{u in} -δ; antenna mirror 1 is fixed on axis 2 rigidly at an angle γ = 90 ^° + δ _in .. For such fixed angles Δ and g, the antenna is precisely guided to the SSISS located strictly in the south, east and west, by rotating the antenna only around the axis E (axis 2).

, имеющим максимальное значение при Φ 45^o. Оценим величину этого рассогласования при принятых значениях r 6364 км, R 42160 км, v 45^o и текущей угловой координате j точки С. Из построений на фиг.5: угол склонения

Из треугольника АСО

При принятых значениях r, R, Φ

Фактический угол

наведения при предлагаемой геометрии инструмента

При принятых значениях r, R, Φ d_ю 6,8043^o, δ_в 6,1193^o, Δ 0,685^o;

.Moreover, in the intermediate positions of GSIS3, there will be some mismatch between the declination angle d _{c of the} corresponding point C of the GSO (see Fig. 3.5) and the actual pointing angle

having a maximum value at Φ 45 ^o . Let us estimate the magnitude of this mismatch with the accepted values of r 6364 km, R 42160 km, v 45 ^o and the current angular coordinate j of point C. From the constructions in Fig. 5: the declination angle

From triangle ASO

For the accepted values of r, R, Φ

Actual angle

guidance with the proposed tool geometry

When the received values r, R, Φ d _w 6,8043 ^o, δ _in 6,1193 ^o, Δ 0,685 ^o;

.

сведены в таблицу.The values calculated using the above formulas

are tabulated.

равно

0,0084^o 0,5 угл. мин, что вполне приемлемо для большинства небольших связевых антенн. Заметим, что при необходимости, максимальное рассогласование может быть уменьшено вдвое за счет уменьшения на

величины установочного угла γ: при этом такая же погрешность

(c обратным знаком) появится в точках Ю и В (ψ 0 и j 90^o).The table shows that the maximum mismatch

equally

0.0084 ^o 0.5 ang. min, which is quite acceptable for most small communication antennas. Note that, if necessary, the maximum mismatch can be halved by decreasing by

installation angle γ: the same error

(with the opposite sign) appears at points Yu and B (ψ 0 and j 90 ^o ).

 When mounting at a given point of dislocation, the antenna is mounted so that its fixed axis E is located strictly in the meridional plane of the Earth (in the north-south direction) under the angle F calculated for the given latitude v to the horizontal. The antenna mirror is fixed at the calculated angle g between the E and F axes. With this installation, the antenna is guided to any GSO point (to any GPSS) within the antenna’s visibility by rotating the antenna mirror around axis E (axis 2) without changing the angles F and g: the F axis of the antenna in this case "slides" according to GSO.

Claims (1)

 A pointed antenna for communication with geostationary artificial Earth satellites, comprising a rotary support device with a fixed axis of rotation located in the meridional plane of the Earth, characterized in that the fixed axis is installed in a direction deviated towards the equator from the polar axis by an angle equal to the difference of the declination angles at pointing the antenna at the points of the geostationary orbit lying in the meridional plane and in the plane perpendicular to it passing through the polar axis.

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