Stray light suppression device for infrared star sensor

Abstract

The utility model provides a stray light suppression device for an infrared star sensor, which comprises a first outer light shield, a second outer light shield, an optical component, a first inner light shield and a second inner light shield which are arranged on the same optical axis, the optical assembly comprises a secondary reflector and a primary reflector which are arranged in the second outer light shield, the primary reflector is arranged at the end, away from the first outer light shield, of the second outer light shield, a light passing opening is formed in the center of the primary reflector, and the secondary reflector is arranged at the end, away from the primary reflector, of the second outer light shield. The first inner light shield and the second inner light shield are arranged in the second outer light shield, the first inner light shield is arranged on the outer side of the secondary reflector in a sleeving mode, the second inner light shield is arranged at the light passing opening of the primary reflector, a plurality of first light blocking rings are arranged on the inner wall of the first outer light shield, and a plurality of second light blocking rings are arranged on the inner wall of the second outer light shield. Therefore, a higher stray light suppression capability is realized.

Description

Technical Field

[0001] The utility model relates to the technical field of star sensor optical systems, in particular to a stray light suppression device for infrared star sensors. Background Art

[0002] Traditional star sensors are key components for satellites to acquire inertial attitude. Star sensors image the stars in the universe and then measure the spacecraft's attitude by calculating the transformation matrix of the stars in the camera coordinate system and the geocentric coordinate system.

[0003] At present, with the continuous development of navigation technology, the requirements for the application scope and application environment of star sensors are getting higher and higher. However, the imaging objects of star sensors are stars, and the signal strength of these stars is weak. In the process of receiving signals, they are easily affected by strong light sources such as sunlight or the reflected light of the moon and the earth. In serious cases, the performance of star sensors is reduced or even unable to work.

[0004] Therefore, star sensors are often equipped with sunshades to suppress or eliminate the influence of stray light from the sun, the earth and the moon, and to expand the observation range of the entire celestial sphere as much as possible. However, the existing sunshades have poor light suppression effect and cannot meet the needs of all-day stargazing.

[0005] Therefore, the utility model is dedicated to providing a stray light suppression device for an infrared star sensor to solve the above problems. Utility Model Content

[0006] The utility model aims to provide a stray light suppression device for an infrared star sensor, which effectively improves the stray light suppression effect of the suppression device, thereby improving the signal-to-noise ratio of the star sensor, by arranging a first outer light shield, a second outer light shield, a first inner light shield and a second inner light shield, and performing stray light suppression design on them.

[0007] The technical solution provided by the utility model is as follows:

[0008] A stray light suppression device for an infrared star sensor comprises a first outer light shield, a second outer light shield, an optical component, a first inner light shield and a second inner light shield, wherein the second outer light shield is arranged at one end of the first outer light shield;

[0009] The optical assembly comprises a secondary reflector and a main reflector arranged in the second outer light shield, the main reflector is arranged at one end of the second outer light shield away from the first outer light shield, a light through hole is opened at the center of the main reflector, and the secondary reflector is arranged at one end of the second outer light shield away from the main reflector;

[0010] The first inner light shield and the second inner light shield are arranged inside the second outer light shield, the first inner light shield is arranged on a side of the secondary reflector close to the primary reflector, and the second inner light shield is arranged at the light opening of the primary reflector;

[0011] A plurality of first light-blocking rings are arranged in sequence on the inner wall of the first outer light-shielding cover, and a plurality of second light-blocking rings are arranged in sequence on the inner wall of the second outer light-shielding cover.

[0012] In some embodiments, an end of the first outer light shield close to the second outer light shield is a small-diameter end, and an end of the first outer light shield away from the second outer light shield is a large-diameter end;

[0013] The inner diameter of the first light shield decreases uniformly and linearly from the large-diameter end to the small-diameter end.

[0014] In some embodiments, a plurality of truss rods are further provided along the circumference of the secondary reflector, and one end of the truss rod away from the secondary reflector is fixedly connected to the inner wall of the second sunshade.

[0015] In some embodiments, the included angle between the first light blocking ring and the inner wall of the first outer light shield is 30°, and the included angle between the second light blocking ring and the inner wall of the first outer light shield is 30°.

[0016] In some embodiments, the number of the first light blocking rings is set to 18, and the number of the second light blocking rings is set to 17.

[0017] In some embodiments, the secondary reflector is disposed at an end of the first inner light shield away from the primary reflector, and an inner diameter of the first inner light shield gradually decreases in a direction approaching the primary reflector;

[0018] The inner diameter of the second inner light shield gradually increases in a direction approaching the main reflector.

[0019] In some embodiments, the inner wall of the first outer light shield and the inner wall of the first inner light shield are sprayed with matte paint, and the absorption rate of the matte paint is greater than 99%.

[0020] In some embodiments, one end of the second inner light shield extends into the light opening and is connected and fixed to the main reflector, and an aperture is provided in the second inner light shield.

[0021] In some embodiments, a locking member is further included, and the locking member is used to connect the first outer light shield and the second outer light shield.

[0022] The utility model provides a stray light suppression device for an infrared star sensor, which has the following features:

[0023] Beneficial effects:

[0024] 1. The utility model provides a stray light suppression device for an infrared star sensor, wherein a second outer light shield is arranged at one end of a first outer light shield, and an optical component is arranged inside the second outer light shield. The first outer light shield and the second outer light shield are used to block stray light (sunlight, moon reflected light, etc.) to achieve a stray light suppression effect, and the first inner light shield and the second inner light shield are arranged to eliminate stray light inside the second outer light shield, thereby achieving a stray light elimination effect of a multi-stage light shield, and the stray light suppression effect is better, which improves the ability of the star sensor to extract weak star signals when observing stars at night and during the day, and makes full use of the space inside the second outer light shield, effectively reducing the volume of the suppression device.

[0025] 2. The utility model provides a stray light suppression device for an infrared star sensor, in which a first light blocking ring is arranged in a first outer light shield, and a second light blocking ring is arranged in a second outer light shield, which can increase the number of reflections of stray light in the first outer light shield and the second outer light shield, thereby enhancing the matte effect of the matte paint.

[0026] 3. The utility model provides a stray light suppression device for an infrared star sensor, wherein the first outer light shield is made of carbon fiber material and the first inner light shield is made of aluminum alloy material, which can further reduce the weight of the suppression device. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The preferred implementation scheme will be described below in a clear and understandable manner with reference to the accompanying drawings to further illustrate the above-mentioned characteristics, technical features, advantages and implementation methods of the present solution.

[0028] Figure 1 This is an internal structure diagram of a stray light suppression device for an infrared star sensor provided by the utility model;

[0029] Figure 2 The utility model provides a PST curve diagram of a stray light suppression device for an infrared star sensor.

[0030] Description of Figure Numbers:

[0031] A first outer light shield 1 , a first light blocking ring 11 , a second outer light shield 2 , a second light blocking ring 21 , a first inner light shield 3 , a second inner light shield 4 , a secondary reflector 5 , a primary reflector 6 , and a light opening 61 . DETAILED DESCRIPTION

[0032] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the specific implementation methods of the utility model will be described below with reference to the accompanying drawings. Obviously, the accompanying drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings and other implementation methods can be obtained based on these drawings without creative work.

[0033] In order to simplify the drawings, only the parts related to the utility model are schematically shown in each figure, and they do not represent the actual structure of the product. In addition, in order to simplify the drawings and facilitate understanding, in some figures, only one of the parts with the same structure or function is schematically drawn or marked. In this article, "one" not only means "only one", but also means "more than one".

[0034] In this document, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0035] In addition, in the description of the present application, the terms "first", "second", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0036] In one embodiment, a stray light suppression device for an infrared star sensor is described, which realizes multi-stage light shielding to process stray light through the cooperation of a first outer light shield 1, a second outer light shield 2, a first inner light shield 3 and a second inner light shield 4, so that the stray light suppression effect is better and the adverse effects of background stray light on the star sensor are effectively reduced.

[0037] Specifically, a stray light suppression device for an infrared star sensor is described, see the accompanying drawings of the specification Figure 1, which comprises a first outer light shield 1, a second outer light shield 2, a first inner light shield 3, a second inner light shield 4 and an optical assembly, wherein the first outer light shield 1, the second outer light shield 2, the first inner light shield 3, the second inner light shield 4 and the optical assembly are arranged on the same optical axis. The second outer light shield 2 is connected to one end of the first outer light shield 1, and the optical assembly is arranged in the second outer light shield 2, and the optical assembly comprises a primary reflector 6 and a secondary reflector 5, wherein the secondary reflector 5 is arranged at one end of the second outer light shield 2 close to the first outer light shield 1, and is suitable for matching with the first inner light shield 3. The primary reflector 6 is arranged at one end of the second outer light shield 2 away from the first outer light shield 1, and a light through port 61 is arranged at the center of the primary reflector 6.

[0038] The inner wall of the first outer light shield 1 is provided with a plurality of first light blocking rings 11 arranged in sequence, and the plurality of first light blocking rings 11 are arranged along the length direction of the first outer light shield 1, and the inner wall of the second outer light shield 2 is provided with a plurality of second light blocking rings 21 arranged in sequence, and the plurality of second light blocking rings 21 are arranged along the length direction of the second outer light shield 2. It can be understood that when stray light enters the first outer light shield 1 and the second outer light shield 2, the stray light is affected by the first light blocking ring 11 and the second light blocking ring 21, and is reflected multiple times, which can further enhance the extinction capability, further suppress the scattered light beam, and prevent it from directly entering the optical component.

[0039] Further, the first inner light shield 3 is arranged on a side of the secondary reflector 5 close to the main reflector 6 and is located inside the second outer light shield 2, and the second inner light shield 4 is arranged at the light opening 61 of the main reflector and is located inside the second outer light shield 2. It should be pointed out that since the main reflector 6 and the second inner light shield 4 are arranged on the same optical axis, and the light opening 61 is located at the center of the main reflector 6, the second inner light shield 4 is located at the light opening 61.

[0040] It can be understood that, compared with the prior art, in which the optical component is arranged on the outside of the light shield, in this embodiment, the first outer light shield 1 and the second outer light shield 2 are connected and arranged in sequence, and the optical component is arranged in the second outer light shield 2, which can significantly reduce the length and volume of the stray light suppression device, so that the device can be suitable for detection with complex backgrounds. The first outer light shield 1 and the second outer light shield 2 can block stray light and achieve preliminary suppression of stray light. Moreover, the first inner light shield 3 and the second inner light shield 4 are arranged in the second outer light shield 2, which can eliminate the stray light entering the second outer light shield 2 and further suppress the stray light. In addition, the stray light entering the stray light suppression device will be reflected multiple times by the first light blocking ring 11 and the second light blocking ring 21, further improving the stray light suppression effect.

[0041] In one embodiment, this embodiment further describes a stray light suppression device for an infrared star sensor, wherein the length of the first outer light shield 1 is 300 mm, the length of the second outer light shield 2 is 8.5 mm, the length of the first inner light shield 3 is 106.9 mm, and the length of the second inner light shield 4 is 48.12 mm.

[0042] In one embodiment, referring to the accompanying drawings, Figure 2 This embodiment further describes a stray light suppression device for an infrared star sensor. The end of the first outer light shield 1 close to the second outer light shield 2 is a small diameter end, the end of the second outer light shield 2 away from the second outer light shield 2 is a large diameter end, and the inner diameter of the first outer light shield 1 decreases uniformly and linearly from the large diameter end to the small diameter end. Furthermore, the inner diameter of the first inner light shield 3 gradually increases in the direction close to the main reflector 6, and the inner diameter of the second inner light shield 4 gradually decreases in the direction close to the main reflector 6, which can further increase the stray light suppression effect.

[0043] In one embodiment, this embodiment further describes the first light-blocking ring 11 and the second light-blocking ring 21. The angle between the first light-blocking ring 11 and the inner wall of the first outer light-shielding cover 1 is 30°, and the angle between the second light-blocking ring 21 and the inner wall of the second outer light-shielding cover 2 is 30°, which is used to control stray light outside the solar shielding angle of 30° from directly entering the optical component, and the first light-blocking ring 11 and the second light-blocking ring 21 are both inclined toward the direction close to the main reflector 6.

[0044] Furthermore, the number of the first light-blocking rings 11 is set to 18, and the number of the second light-blocking rings 21 is set to 17, so that stray light can be fully reflected by the inner walls of the first outer light-blocking cover 1 and the second outer light-blocking cover 2 to prevent it from directly entering the optical component.

[0045] In one embodiment, the inner wall of the first outer light shield 1 is sprayed with matte paint, and the absorption rate of the matte paint is greater than 99%.

[0046] It can be understood that, on the one hand, the stray light entering the first outer light shielding cover 1 and the second outer light shielding cover 2 can be reflected multiple times under the action of the first light blocking ring 11 and the second light blocking ring 21 to gradually eliminate the stray light, and in the process of reflection of the stray light, it is gradually absorbed by the matte paint, thereby further reducing the stray light suppression effect.

[0047] In actual production applications, the matte paint uses NIR black paint coating.

[0048] In one embodiment, one end of a second inner light shield 4 of a stray light suppression device for an infrared star sensor is inserted into a light opening 61 and fixedly connected to a main reflector 6, and an aperture is provided in the second inner light shield 4 and placed at a position of a first real image plane of the entire optical system as a stray light elimination aperture, which can further suppress stray light from reaching the image plane, thereby improving the ability of the star sensor to extract weak star signals.

[0049] It can be understood that in the above embodiment, by adopting a combination arrangement of the first outer light shield 1, the second outer light shield 2, the first inner light shield 3 and the second inner light shield 4, and arranging a first light blocking ring 11 in the first outer light shield 1, and a second light blocking ring 21 in the second outer light shield 2, and spraying matte paint, the sunlight, the reflected light of the moon, the scattered background of the atmosphere, and the stray light reflected by the earth can be fully suppressed, and the stray light suppression effect is good.

[0050] In one embodiment, a stray light suppression device for an infrared star sensor also includes a plurality of truss rods, which are arranged along the circumference of the secondary reflector 5, one end of each truss rod is connected to the secondary reflector 5, and the other end of the truss rod is fixedly connected to the inner wall of the second outer sunshade 2 to achieve the installation and fixation of the secondary reflector 5.

[0051] Furthermore, it also includes a locking member for connecting the first outer light shield 1 and the second outer light shield 2. Specifically, an extension protrusion is provided at one end of the first outer light shield 1 and the second outer light shield 2 that are close to each other, the extension protrusion of the first outer light shield 1 is provided along the circumference of the first outer light shield 1, and the extension protrusion of the second outer light shield 2 is provided along the circumference of the second outer light shield 2. A threaded hole is provided on each extension protrusion, and the locking member is provided as a bolt that matches the threaded hole to achieve the connection and fixation of the first outer light shield 1 and the second outer light shield.

[0052] Furthermore, the first outer light shield 1 is made of carbon fiber material, and the first inner light shield 3 is made of aluminum alloy material, which can reduce the weight of the stray light suppression device.

[0053] In addition, see the attached drawings of the specification Figure 2 , Figure 2This is the PST diagram of the stray light suppression device. PST (point source transmittance), that is, the point source transmittance, is used to indicate the ability of the optical system to suppress point stray light sources (the sun and the moon). The point source transmittance reflects the level of suppression of stray light by the sunshade itself. Among them, the value of PST is generally obtained by PST (θ) = Ed (θ) / EI (θ), θ is the off-axis angle of the stray light source, Ed (θ) is the irradiance received by the detector, and EI (θ) is the irradiance at the entrance of the optical system. PST reflects the attenuation ability of point source stray light after entering the optical system. The smaller the PST, the stronger the ability of the optical system to suppress stray light. It can be seen from the simulation data that when the solar shielding angle is 20°, the PST curve drops sharply. This is because when the solar shielding angle is less than 20°, the stray light source can directly irradiate the main reflector 6, and the stray light is mainly generated by scattering between the main reflector 6 and the secondary reflector 5. The energy of the stray light on the image plane is relatively large. When the off-axis angle is greater than 20°, after the stray light source enters the optical system, it first passes through the attenuation of the first outer light shield 1, the second outer light shield 2, the first light blocking ring 11, the first inner light shield 3, the second inner light shield 4 and the second light blocking ring 21, and the stray light energy that finally reaches the detector is small. In addition, it can be seen that when the off-axis position is 0.707° (sunlight shielding angle 0.707°), PST0.707°<1×10-1, and when the off-axis position is 30° (sunlight shielding angle 30°), PST30°<1×10-7, it can be seen that the utility model has a good effect of suppressing stray light.

[0054] It should be noted that the above embodiments can be freely combined as needed. The above is only a preferred implementation of the utility model. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the utility model, and these improvements and modifications should also be regarded as the protection scope of the utility model.

Claims

1. A stray light suppression device for an infrared star sensor, characterized in that: It comprises a first outer light shield, a second outer light shield, an optical component, a first inner light shield and a second inner light shield, which are arranged on the same optical axis, wherein the second outer light shield is arranged at one end of the first outer light shield; The optical assembly includes a primary reflector disposed in the second outer light shield and a secondary reflector matched with the first inner light shield, the primary reflector being disposed at one end of the second outer light shield away from the first outer light shield, a light passage opening being provided at the center of the primary reflector, and the secondary reflector being disposed at one end of the second outer light shield away from the primary reflector; The first inner light shield and the second inner light shield are arranged inside the second outer light shield, the first inner light shield is arranged on a side of the secondary reflector close to the primary reflector, and the second inner light shield is arranged at the light opening of the primary reflector; The inner wall of the first outer light shield is provided with a plurality of first light blocking rings arranged along the length direction of the first outer light shield, and the inner wall of the second outer light shield is provided with a plurality of second light blocking rings arranged along the length direction of the second outer light shield.

2. The stray light suppression device for an infrared star sensor according to claim 1, characterized in that: An end of the first outer light shield close to the second outer light shield is a small-diameter end, and an end of the first outer light shield away from the second outer light shield is a large-diameter end; The inner diameter of the first outer light shield decreases uniformly and linearly from the large-diameter end to the small-diameter end.

3. The stray light suppression device for an infrared star sensor according to claim 2, characterized in that: It also includes a plurality of truss rods arranged along the circumference of the secondary reflector, and one end of the truss rod away from the secondary reflector is fixedly connected to the inner wall of the second outer light shield.

4. The stray light suppression device for an infrared star sensor according to claim 3, characterized in that: The included angle between the first light blocking ring and the inner wall of the first outer light shield is 30°, and the included angle between the second light blocking ring and the inner wall of the second outer light shield is 30°.

5. The stray light suppression device for an infrared star sensor according to claim 4, characterized in that: The number of the first light blocking rings is set to 18, and the number of the second light blocking rings is set to 17.

6. The stray light suppression device for an infrared star sensor according to claim 5, characterized in that: The inner diameter of the first inner light shield gradually increases in a direction approaching the main reflector, and the inner diameter of the second inner light shield gradually decreases in a direction approaching the main reflector.

7. A stray light suppression device for an infrared star sensor according to any one of claims 1 to 6, characterized in that: The inner wall of the first outer light shield and the inner wall of the first inner light shield are sprayed with matte paint, and the absorption rate of the matte paint is greater than 99%.

8. The stray light suppression device for an infrared star sensor according to claim 7, characterized in that: One end of the second inner light shield extends into the light opening and is connected and fixed to the main reflector. An aperture is arranged in the second inner light shield.

9. The stray light suppression device for an infrared star sensor according to claim 1, characterized in that: It also includes a locking member, which is used to connect the first outer light shield and the second outer light shield.

10. The stray light suppression device for an infrared star sensor according to claim 1, characterized in that: The first outer sunshade is made of carbon fiber material; and / or The first inner light shield is made of aluminum alloy.

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