RU2694458C1 - Device for near-spacecraft relative position control - Google Patents

Abstract

FIELD: instrument engineering.

SUBSTANCE: invention relates to the field of optoelectronic instrument making and is intended for use in spacecraft motion control systems. Claimed device for near-spacecrafts relative position control comprises a target mounted on passive spacecraft and emitters. In the output window of the target there is an emitter in form of a rectangular cross, the center of which crosses the origin of the coordinate system of the target OXYZ, axes of symmetry of sides of cross coincide with axes OY and OZ, axis OX is directed from center of cross-hair towards radiation. Behind the cross inside the target there is a spherical mirror whose optical axis coincides with the axis OX of the target. Between the cross and the spherical mirror there is an emitter with a mask facing the spherical mirror, at a distance from the mirror corresponding to the formation of a larger virtual mask image. Position of this image, visible from the side of the active spacecraft, against the backdrop of the luminous cross, makes it possible to estimate angular deviations of the axis of the passive spacecraft from the axis of the active spacecraft. Photodetector mounted on the outer surface of the target is electrically connected to the radiator control unit, which enables to control the orientation of the spacecraft in a wide range of background illumination of the target on the day and night side of the orbit.

EFFECT: high ergonomic characteristics and broader functional capabilities of the device for monitoring the relative position of spacecraft when approaching.

1 cl, 5 dwg

Description

The invention relates to the field of opto-electronic instrumentation and is intended for use in motion control systems (DMS) of a spacecraft (SC) to provide operations for the approach and docking of spacecraft.

Analogues of the proposed device are docking targets used in the operations of approaching and docking of the spacecraft. These targets are described in the literature: “Encyclopedia of Mechanical Engineering, Volume IV-22, Rocket and Space Technology, Book 2, Part II, Chapter 4.4. Traffic control and navigation system. Moscow "Mechanical Engineering" 2014 ".

The docking target is a metal structure having a base with black coating and a white cross applied, a rod mounted perpendicular to the base along the axis of the target and an external cross at the end of the rod. Remote cross has a white coating. When observed along the target axis in the absence of a mismatch of the axes of converging spacecraft, the remote cross coincides with the cross on the basis of the target. Docking targets are used in the manual motion control loop of the spacecraft and in automatic mode for the operator to control the approach and docking process. Observations of the docking target are carried out through a special optical sight, or with the help of a television camera. The disadvantage of such targets is that their visibility depends on the lighting conditions. On the day side of the orbit, such a case of solar SC illumination is possible, where, due to the complex configuration of the spacecraft, the docking target may be in the shadow of the structural elements of the spacecraft, and the target will be poorly visible in the television image due to the large difference in brightness. On the night side of the orbit, when two spacecraft approach the active spacecraft, they use an LED headlight to illuminate the second spacecraft. Due to the parallax between the axis of sight of the television camera and the axis of radiation of the headlamp, at a distance of five and three meters, the base of the target is in the cone of radiation of the headlamp, and the remote cross is outside the cone in penumbra. As a result, due to the large difference in brightness, the remote cross disappears on the television image.

The prototype can be taken device, presented in the patent RU 2478185 C1 "Device for determining the spatial orientation of objects." The device contains a target with reflective prisms installed on one object (on a passive spacecraft), as well as two emitters with marks, a beam splitter, a lens, a shutter and a photoreceiver installed on another object. The emitters and the marks illuminated by them lie in the plane perpendicular to the focal plane of the lens, and the marks lie on the line of intersection of these planes. The rays from the marks, passing through the beam splitter and the lens, reflected from the target, fall into the lens and, passing through the beam splitter, fall on the photoreceiver associated with the computer. A rotary shutter in front of the lens, alternately overlapping the rays from one or another radiator, is designed to sub-focus the lens for each of the images of the two masks. According to the location of the mask image on the photodetector, the relative angular position of two objects in the same plane is calculated.

The disadvantage of this device, in relation to the solution of the problem of monitoring the relative position of two spacecraft, is that it allows you to control the angular displacement in only one plane. Other disadvantages are the presence of mechanisms: a rotary shutter, a lens focusing mechanism, which, under space flight conditions, reduces the reliability coefficient.

The present invention is to improve the ergonomic characteristics and the expansion of the functional capabilities of the device to control the relative orientation of the spacecraft when approaching.

The technical result is achieved by the fact that in the device for monitoring the relative position of approaching spacecraft containing a target mounted on a passive spacecraft, as well as emitters, in contrast to the known, the emitter in the form of a rectangular cross is located in the plane of the target window of the target, behind it is a spherical mirror The optical axis of which is perpendicular to the plane of the exit window and passes through the center of the crosshair, between the cross and the spherical mirror there is an emitter with a mask facing spherical mirror and located at a distance corresponding to the formation of an enlarged imaginary image of a mask having the form of a luminous ring with four bisectors around it, the optical axis of the spherical mirror intersecting the center of the luminous ring and the symmetry axes of the sides of the cross on the outer The front surface of the target is a photodetector electrically connected to the control unit emitters.

The technical result is achieved by allowing the device to be used in the motion control system of an active spacecraft, when performing mutual orientation control when approaching a passive spacecraft under any lighting conditions, both on the day and on the night side of the orbit.

The essence of the invention is illustrated graphic materials:

FIG. 1 - Target cross section in the XOZ plane;

FIG. 2 - Type A;

FIG. 3 - Mutual position of the coordinate systems of two spacecraft;

FIG. 4 - View of the target from the side of the active spacecraft when the target turns around the OY axis at an angle ϑ and around the OZ axis at an angle;

FIG. 5 - Functional diagram of the device.

List of positions:

1 - emitter in the form of a rectangular cross,

2 - spherical mirror,

3 - emitter with mask,

4 - target body

5 - mask

6 - the plane of localization of the image of a luminous mask obtained using a spherical mirror,

7 is an image of a luminous mask enlarged by a spherical mirror,

8 is an enlarged spherical mirror image of luminous Bishtrich masks,

9 - photodetector,

10 - control unit emitters, to - point in the plane of the mask,

k '- the image of the point to the mask in the image plane,

F is the focal point of the spherical mirror,

- расстояние от плоскости прямоугольного креста до плоскости маски,

- the distance from the plane of the rectangular cross to the plane of the mask,

- расстояние от плоскости маски до точки O₁ сферического зеркала,

- the distance from the plane of the mask to the point O _{1 of the} spherical mirror,

p is the distance from the plane of the rectangular cross to the point F,

ƒ is the focal length of the spherical mirror,

x is the distance from point F to the plane of the mask,

x 'is the distance from point F to the plane of the mask image.

A volumetric target with radiators is mounted on the body of a passive spacecraft outside near the docking port so that the axis OX of the target is parallel to the axis OX KA. In the exit window 5 of the target, the emitter is located in the form of a rectangular cross 1. The axes of symmetry of the sides of the cross coincide with the axes OY and OZ of the target, and the center of the crosshair coincides with the point O, which is the origin of the coordinate system of the OXYZ target. Inside the bulk target there is a spherical mirror 2, the optical axis of which O ₁ F coincides with the axis OX. On the OX axis, between the cross 1 and the spherical mirror 2, there is an emitter 3 with a mask 5 that coincides with the plane perpendicular to the optical axis O ₁ F of the spherical mirror 2. The mask has the form of a ring whose center lies on the axis O ₁ F and also as bishtrikhs located in 90 ° increments, outside the ring. The image of the mask 5 in the spherical mirror 2 is localized in the plane 6, perpendicular to the axis OX. In accordance with the laws of geometrical optics, the position of an object and its image obtained using an optical system, in our case a spherical mirror 2, can be determined by the formula:

where x is the distance from the point of focus F to the point O ₂ , which is the projection of the point to the mask 5 on the optical axis O ₁ F,

- проекции точки k' на оптическую ось O₁F,x 'is the distance from point F to point

- the projection of the point k 'on the optical axis O ₁ F,

ƒ is the focal length of the mirror.

The linear increase in β of the image of the mask 5, located in the plane 6 according to the laws of geometric optics, is determined by the formula:

To protect against overheating of the rectangular cross and the emitter with a mask when the direct radiation of the Sun enters the angular field of the spherical mirror, there must be a distance p between the point of focus F of the spherical mirror and the position of the rectangular cross so that there is no focused image of the Sun on the surface of the rectangular cross facing spherical mirror.

FIG. 2 shows the relative position of the rectangular cross the target 1, the spherical mirror 2, an image of the luminous rings 7 and 8 in coincidence bishtrihov position sighting axis O _A X _A with the x-axis target.

When the target is rotated around the OY axis at an angle ϑ and around the OZ axis at an angle ψ, as shown in FIG. 3, the mutual position of the rectangular cross 1 and the image of the luminous ring 7 and bishtrich 8 when viewed along the axis of sight O _A X _A will be, as shown in FIG. four.

Габаритный размер предлагаемой в заявке мишени определяется расстоянием вдоль оптической оси между излучателем в виде прямоугольного креста и центром сферического зеркала

а именно:Overall dimension along the axis of sight of a mechanical docking target consisting of a base in the shape of a black pentagon with a white cross and white strokes along the edges of the base, as well as a white offset cross on the rod fixed in the center of the cross on the base is determined by the length of the rod

The overall size of the proposed in the application of the target is determined by the distance along the optical axis between the emitter in the form of a rectangular cross and the center of a spherical mirror

namely:

при этом обе мишени будут иметь одинаковые смещения при наблюдении по оси визирования для одинаковых угловых разворотах мишеней.For comparison, the two targets take

while both targets will have the same displacement when observed along the axis of sight for the same angular spreads of the targets.

The reduction in overall size along the axis of sight of the proposed target, compared with the mechanical target of docking, is expressed in terms of the coefficient K _L , determined by the formula:

As an example, we calculate by the formula (4) the coefficient K _L for the following target parameters:

After substituting the specified values of the parameters in formula (4), we obtain K _L = 3.5. As you can see, the proposed target allows several times to reduce the size of the target along the axis of sight.

According to the task, the target should provide control of the mutual orientation of active and passive spacecraft, both on the day and on the night side of the orbit. The relative orientation is controlled by the operator using a television camera. The operator must clearly see not only the image of the target, but also the surrounding structural elements of the passive spacecraft with which the approach is made.

On the night side of the orbit, when approaching, the passive spacecraft with a target mounted on it is illuminated by a headlight placed on the active spacecraft. The illumination of a passive spacecraft is inversely proportional to the square of the distance from the headlight to the surface of the passive spacecraft:

Where

Е _{п_фара} - illumination of passive spacecraft from the headlight on the active spacecraft,

I ₀ - axial luminous intensity

L is the distance from the active spacecraft to the passive spacecraft.

When I ₀ = 30000 Cd, L = 30 m, E _{p_fire} = 33.33 Cd / m ² ,

When I ₀ = 30000 Cd, L = 4 m, E _{p_fara} = 1875 Cd / m ² .

We believe that the surface of a passive spacecraft has a uniform indicatrix of scattering of rays, and the reflection coefficient (albedo) And _n = 0.5. Then the brightness of the surface of the passive KA In _{p_fara_} , calculated by the formula:

will be for L = 30 m В _{п_фара_30m} ≈5 Cd / (m ² × _С ter),

for L = 4 m В _{п_фара_4м} ≈298 Kd / (m ² × _С ter).

On the day side of the orbit, the illumination of the surface of a passive spacecraft, facing in the direction of the line of sight of the active spacecraft, depends on the angle of incidence of sunlight to this surface:

Where

ϕ is the angle of incidence of sunlight to the surface of the spacecraft,

Е _{п_Солце_0} ^{_ the} illumination of the spacecraft's surface with normal incidence of sunlight (ϕ = 0),

Е _{п_Солнце_ϕ} - illumination of the spacecraft's surface at the angle of incidence of the sun's rays ϕ> 0 degrees.

At the boundary of the earth's atmosphere, with an average distance of the Earth from the Sun, for the visible wavelength range, E _{p_sun_0 ≈140000} cd / m ² , and the surface brightness of the passive spacecraft In _p _ _{Sun_0} ≈22280 cd / (m ² × ster).

As shown above, according to expressions (5) and (7), the lighting conditions of a passive spacecraft change on the night side of the orbit with a change in the distance between the spacecraft, and on the day side, change with change in the angle of incidence of sunlight on the surface of the passive spacecraft. Consequently, the brightness of the surface of a passive spacecraft, depending on the lighting conditions, may differ by several orders of magnitude:

The TV camera on the active spacecraft automatically adjusts to the average brightness of the observed objects during operation. The target emitters must also adjust to the light conditions of the passive SC, so that the brightness of the target emitters is at least 2 times higher than the average brightness of the background surrounding the target (surface of the passive SC), but do not go beyond the dynamic range of the television camera so that her dazzle. To ensure this condition on the outer surface of the target is a photodetector 9, electrically connected with the control unit emitters. The connections of the emitters of the target 1 and 3, the control unit of the emitters 10 and the photodetector 9 are shown in the functional diagram of FIG. five.

The proposed device can be used as a docking target in a motion control system of both manned spacecraft and cargo transport satellites to provide a teleoperative control mode (TORU).

Claims (1)

A device for monitoring the relative position of approaching spacecraft, containing a target mounted on a passive spacecraft, as well as radiators, characterized in that the emitter in the form of a rectangular cross is located in the plane of the target target window, behind it is a spherical mirror, the optical axis of which is perpendicular to the plane of the output window and passes through the center of the crosshair, between the cross and the spherical mirror is a radiator with a mask facing the spherical mirror and is located At a distance corresponding to the formation of an enlarged imaginary image of a mask that looks like a luminous ring with four bisectors around it, the optical axis of the spherical mirror intersects the center of the luminous ring, and the symmetry axes of the bisector coincide with the axes of symmetry of the sides of the cross, a photodetector is located on the outer front surface of the target, electrically connected to the radiator control unit.

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