Two-dimensional expansion type SAR satellite

Abstract

The invention provides a two-dimensional expansion type SAR satellite in the field of SAR satellites. The two-dimensional expansion type SAR satellite comprises a satellite body, an SAR antenna, a solar array, a phased array data transmission antenna, a star sensor, an antenna measurement and control antenna, a ground wire measurement and control antenna, an electric thruster and other key components. A unique two-dimensional unfolding mechanism is adopted in the satellite design, so that the satellite can be loaded with a larger SAR (Synthetic Aperture Radar) antenna; the solar array is folded and pressed on the side face of the satellite body, the phased array data transmission antenna and the ground wire measurement and control antenna are installed on the side face (to the ground) of the satellite body, and the star sensor is installed on the top of the satellite body through a carbon fiber support. Space envelope resources in the fairing are fully utilized, the satellite is small in size in the folded state, the satellite structure is stable and reliable, and the fairing can adapt to various observation tasks.

Description

Technical Field

[0001] The present invention belongs to the field of spacecraft satellites, and in particular, relates to a two-dimensional unfoldable SAR satellite. Background Art

[0002] Synthetic aperture radar (SAR) satellites have all-day and all-weather characteristics, effectively making up for the shortcomings of optical remote sensing satellites, significantly improving the efficiency of mission execution, and have been widely used in surveying and mapping, ocean, earthquake, and national defense.

[0003] Traditional SAR satellites are usually rigidly connected to the satellite body, and the SAR antenna area is limited, which limits the size and performance of the antenna, and thus affects the imaging resolution and quality. With the continuous development of radar payload capabilities, the aperture area and volume envelope of the payload antenna are getting larger and larger, and a variety of new satellite configurations have emerged, one of which is a SAR satellite with a deployable design. This design can fold a large antenna in the fairing to fit the envelope of the fairing, and the antenna can be unfolded in orbit to achieve the required performance indicators.

[0004] In existing designs, deployable SAR satellites are usually deployed in one dimension. The disadvantage of this design is that the antenna deployment area cannot keep up with the development trend, and it limits the size of the antenna that cannot be deployed in that dimension. Therefore, a two-dimensional deployable SAR satellite configuration is urgently needed to solve this problem.

[0005] According to the prior art search, the Chinese patent CN112009724B discloses a wedge-shaped satellite configuration and its assembly method. The wedge-shaped satellite configuration includes a configuration body, which is a heptahedral wedge configuration and a closed space formed by seven side panels. The configuration of this patent is not suitable for the installation of large deployable antennas.

[0006] The Chinese patent document CN110450983B discloses an agile satellite configuration. This patent is suitable for satellites with compact layout and small inertia, but is not suitable for carrying large antennas.

[0007] The Chinese patent document CN109927938B discloses a geostationary orbit real aperture microwave detection satellite configuration. The satellite configuration of the patent is for the geostationary orbit real aperture microwave detection satellite, and its payload is a parabolic antenna.

[0008] The Chinese patent document CN107600460B discloses a cryogenic optical satellite configuration suitable for the complex lighting conditions of a large elliptical frozen orbit. The patent aims to ensure that the satellite has a stable large-size sun-facing surface under the complex lighting conditions of a large elliptical frozen orbit to ensure the imaging temperature environment requirements of the cryogenic optical camera.

[0009] The Chinese patent document CN109927937B discloses a separated solar observation satellite configuration that can achieve full physical space isolation between cabins and eliminate the micro-vibration effect of the satellite platform on the payload, but does not involve the description of large antenna loading.

[0010] The Chinese patent document CN114744391B discloses a device for deploying a micro-satellite SAR antenna, including: a connecting rod mechanism, a sliding mechanism and a locking mechanism, wherein the connecting rod mechanism is connected between the satellite body and the antenna; the connecting rod mechanism is folded or unfolded under the action of the sliding mechanism, and is folded or unfolded synchronously with the antenna; when the connecting rod mechanism is gradually unfolded from a folded state to a maximum position, the sliding mechanism is connected to the locking mechanism and self-locks.

[0011] Patent document CN116995400A discloses a multi-fold array deployable antenna. However, the deployment of patent document CN116995400A has many steps, complex movements, and low reliability of the deployment mechanism. Specifically, due to its deployment method, it has many folding times, and more sub-boards are connected by hinges to form the deployed array surface. This array surface has low flatness and rigidity, and cannot guarantee temperature consistency in orbit (usually heat pipes are embedded in the sub-boards); it is impossible to set struts to improve the flatness of the array surface. The flatness of the SAR satellite array surface is a key indicator that affects its performance. In addition, the array surface of the patent document CN116995400A is connected to the satellite body by hinges after deployment, which is relatively flexible and difficult to control the satellite attitude. Summary of the invention

[0012] In view of the defects in the prior art, an object of the present invention is to provide a two-dimensional unfoldable SAR satellite.

[0013] A two-dimensional deployable SAR satellite provided by the present invention comprises: a satellite body, a SAR antenna and a solar array;

[0014] The satellite is a rectangular three-dimensional shape. Before the satellite enters orbit, the solar array and the SAR antenna are folded, the SAR antenna covers three sides of the satellite, and the solar array covers the remaining side of the satellite. After the satellite enters orbit, the solar array and the SAR antenna are unfolded in sequence. The SAR antenna is unfolded in two dimensions to form a whole antenna array surface.

[0015] The SAR antenna and the solar array are respectively connected to the star body in an articulated manner; a ground line measurement and control antenna, an antenna measurement and control antenna and a phased array data transmission antenna are installed on the side of the star body; a star sensor is installed on the top plate of the star body; and an electric thruster is installed on the bottom plate of the star body.

[0016] Preferably, the coordinate relationship is described as follows:

[0017] The origin of the stellar coordinates O is the satellite's mass center;

[0018] The X axis is the satellite flight direction;

[0019] The Z axis is perpendicular to the mounting surface of the SAR antenna mid-board, and the positive direction points to the outside of the satellite;

[0020] The Y axis, X axis and Z axis form a right-handed rectangular coordinate system.

[0021] Preferably, a plurality of star sensors are installed on the top plate of the star body, and the star sensors are fixedly connected to the star body through an integrated carbon fiber bracket.

[0022] Preferably, a rail-mounted electric thruster is installed on the satellite body base plate.

[0023] Preferably, a ground-tracking measurement and control antenna is installed on the side +Z side of the satellite body close to the bottom plate.

[0024] Preferably, one phased array data transmission antenna is installed on each of the left and right sides of the side +Z side of the star body near the bottom plate, and is placed symmetrically in the horizontal line, and one of the phased array data transmission antennas is installed adjacent to the ground line measurement and control antenna.

[0025] Preferably, on the side - Z side of the star, on the same side as the solar array, close to the bottom plate, one sky tracking and control antenna is installed on each side, symmetrically placed on the horizontal line.

[0026] Preferably, after the SAR antenna is deployed in orbit, it is connected to the satellite through a SAR antenna deployment mechanism, and the six flat plates of the SAR antenna are fully deployed and connected to the satellite through two deployment mechanisms installed on the left and right sides of the satellite;

[0027] The plates are hinged with 90° hinges and / or 80° hinges;

[0028] A support rod is set behind the flat plate to ensure the flatness of the surface;

[0029] One of the six plates is firmly connected to the star;

[0030] Heat pipes are embedded in the flat panel.

[0031] Preferably, when the satellite is in orbit, the two ±Y sub-boards of the solar array are unfolded to both sides in sequence until the direction of the solar array against the surface of the star body points to the -Z direction, and the solar array is unfolded in a straight line, and the solar array is symmetrical relative to the star body.

[0032] Preferably, after the satellite enters orbit, it is deployed step by step in the order of first deploying the solar array and then deploying the SAR antenna. When the solar array is deployed, its deployment path does not interfere with other components outside the satellite.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] 1. The present invention can greatly increase the area of ​​the unfolded SAR antenna by two-dimensionally unfolding the SAR antenna. The large-area SAR antenna can provide higher resolution and stronger signal coverage capability.

[0035] 2. The present invention makes full use of the space envelope resources inside the fairing, effectively reducing the envelope of the entire satellite when retracted. The satellite is small in size in the retracted state, and the satellite structure is stable and reliable, suitable for a variety of transportation and observation tasks.

[0036] 3. The present invention is simple and reliable to implement, does not have an overly complicated unfolding mechanism, and is easy and convenient to operate.

[0037] 4. The present invention has a simple unfolding form and can be realized by using a 90° hinge and an 80° hinge, with high reliability and easy engineering implementation. Furthermore, the present invention arranges a support rod at the back to ensure the flatness of the array surface, and one of the six plates is fixedly connected to the satellite body. After unfolding, the array surface has low flexibility and is easy for satellite attitude control. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings:

[0039] Figure 1 It is a schematic diagram of the folded state of the two-dimensional deployable SAR satellite of the present invention.

[0040] Figure 2 It is a schematic diagram of the in-orbit deployment state of the two-dimensional deployable SAR satellite of the present invention.

[0041] Figure 3 It is a schematic diagram of the two-dimensional unfolding process of the SAR satellite of the present invention.

[0042] The figure shows:

[0043] DETAILED DESCRIPTION

[0044] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several changes and improvements can also be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0045] like Figure 1 As shown, the present invention provides a two-dimensional deployable SAR satellite, including: a star body, a SAR antenna, a solar array, a phased array data transmission antenna, a star sensor, an antenna measurement and control antenna, a ground line measurement and control antenna, an electric thruster and a SAR antenna deployment mechanism.

[0046] Before the satellite enters orbit, the SAR antenna and the solar array are in a retracted state, wherein the SAR antenna covers three sides of the satellite body, and the solar array covers the remaining side of the satellite body; the SAR antenna and the solar array are respectively hingedly connected to the satellite body; the side of the satellite body is equipped with a ground-to-ground measurement and control antenna, an antenna-to-antenna measurement and control antenna and a phased array data transmission antenna; the top plate of the satellite body is equipped with a star sensor; and the bottom plate of the satellite body is equipped with an electric thruster.

[0047] After the satellite enters orbit, Figure 2 , Figure 3 As shown, the solar array is deployed step by step in the order of first deploying the solar array and then deploying the SAR antenna. When the solar array is deployed, its deployment path does not interfere with other components outside the satellite. The SAR antenna is deployed twice to form a whole antenna array surface.

[0048] The coordinate system involved in the present invention is described as follows:

[0049] The coordinate origin O is the satellite's center of mass;

[0050] The X axis is the satellite flight direction;

[0051] The Z axis is perpendicular to the mounting surface of the SAR antenna mid-board, and the positive direction points to the outside of the satellite;

[0052] The Y axis, X axis and Z axis form a right-handed rectangular coordinate system.

[0053] The SAR antenna is folded into a π shape and pressed against the three sides of the satellite body, such as Figure 2 , Figure 3 As shown in the figure, after the satellite enters orbit, the SAR antenna is unfolded in two dimensions, and forms a whole plane after being unfolded in place; the solar array is installed on the side of the satellite body, and the ±Y sub-boards of the solar array are unfolded successively after entering orbit. When in orbit, the attitude maneuver of the whole satellite is used to ensure the sun orientation to improve the charging efficiency of the solar array; the phased array data transmission antenna and the ground line measurement and control antenna are installed on the +Z side of the satellite platform (towards the ground); the antenna measurement and control antenna is installed on the -Z side of the satellite platform, and 3 star sensors are installed on the top plate of the satellite using an integrated carbon fiber bracket.

[0054] The present invention occupies a small space in the fairing, has a stable structure and can meet the mechanical environment of the active launch section, realizes the two-dimensional deployment of the SAR antenna on orbit, and greatly increases the deployment area of ​​the SAR antenna.

[0055] In the description of the present application, it should be understood that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0056] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which does not affect the essence of the present invention. In the absence of conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

Claims

1. A two-dimensional deployable SAR satellite, characterized in that: include: Stars, SAR antennas, and solar arrays; The satellite is a rectangular three-dimensional shape. Before the satellite enters orbit, the solar array and the SAR antenna are folded, the SAR antenna covers three sides of the satellite, and the solar array covers the remaining side of the satellite. After the satellite enters orbit, the solar array and the SAR antenna are unfolded in sequence. The SAR antenna is unfolded in two dimensions to form a whole antenna array surface. The SAR antenna and the solar array are respectively connected to the star body in an articulated manner; a ground line measurement and control antenna, an antenna measurement and control antenna and a phased array data transmission antenna are installed on the side of the star body; a star sensor is installed on the top plate of the star body; and an electric thruster is installed on the bottom plate of the star body.

2. The two-dimensional deployable SAR satellite according to claim 1, characterized in that: The coordinate relationship is described as follows: The origin of the stellar coordinates O is the satellite's mass center; The X axis is the satellite flight direction; The Z axis is perpendicular to the mounting surface of the SAR antenna mid-board, and the positive direction points to the outside of the satellite; The Y axis, X axis and Z axis form a right-handed rectangular coordinate system.

3. The two-dimensional deployable SAR satellite according to claim 1, characterized in that: A plurality of star sensors are installed on the top plate of the star body, and the star sensors are fixedly connected to the star body through an integrated carbon fiber bracket.

4. The two-dimensional deployable SAR satellite according to claim 1, characterized in that: Rail-mounted electric thrusters are installed on the satellite base plate.

5. The two-dimensional deployable SAR satellite according to claim 2, characterized in that: A ground-tracking measurement and control antenna is installed on the +Z side of the satellite near the bottom plate.

6. The two-dimensional deployable SAR satellite according to claim 2, characterized in that: A phased array data transmission antenna is installed on each of the left and right sides of the side +Z side of the satellite near the bottom plate, symmetrically placed in the horizontal line, and one of the phased array data transmission antennas is installed adjacent to the ground line measurement and control antenna.

7. The two-dimensional deployable SAR satellite according to claim 2, characterized in that: On the side of the star - the Z side, on the same side as the solar array, there is a sky tracking and control antenna installed on each side close to the bottom plate, symmetrically placed on the horizontal line.

8. The two-dimensional deployable SAR satellite according to claim 7, characterized in that: After the SAR antenna is deployed in orbit, it is connected to the satellite through the SAR antenna deployment mechanism. The six flat plates of the SAR antenna are fully deployed and connected to the satellite through two deployment mechanisms installed on the left and right sides of the satellite; The plates are hinged with 90° hinges and / or 80° hinges; A support rod is set behind the flat plate to ensure the flatness of the surface; One of the six plates is firmly connected to the star; Heat pipes are embedded in the flat panel.

9. The two-dimensional deployable SAR satellite according to claim 8, characterized in that: When the satellite is in orbit, the two ±Y sub-boards of the solar array are unfolded to both sides in sequence until the direction of the solar array against the surface of the satellite points to the -Z direction. The solar array is unfolded in a straight line and is symmetrical relative to the satellite.

10. The two-dimensional deployable SAR satellite according to claim 1, characterized in that: After the satellite enters orbit, it is deployed step by step in the order of first deploying the solar array and then the SAR antenna. When the solar array is deployed, its deployment path does not interfere with other components outside the satellite.

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