Method and system for acquiring satellite-borne antenna pointing information using distributed multi-star sensors

Abstract

This invention provides a method and system for acquiring satellite-borne antenna pointing information using distributed multi-star sensors, comprising: a satellite equipped with a radar antenna, a platform star sensor, a measurement antenna, and a measurement star sensor; establishing a measurement star sensor observation coordinate system and a measurement antenna coordinate system; obtaining a first transformation relationship based on the relationship between the measurement antenna and the measurement star sensor; obtaining a second transformation relationship through bidirectional microwave transmission and reception between the measurement antenna and the radar antenna; the measurement star sensor and the platform star sensor synchronously observing stars and matching them with the same star map to obtain a third transformation relationship; and using the first, second, and third transformation relationships, performing a fusion transformation according to a formula to obtain the radar antenna beam pointing information in the platform star sensor observation coordinate system. This invention utilizes multiple star sensors distributed at different locations on the satellite for synchronous measurement and data fusion to obtain the on-orbit beam pointing information of the satellite-borne radar antenna.

Description

Technical Field

[0001] This invention relates to the technical field of on-orbit beam pointing information of spaceborne radar antennas, specifically, to a method and system for acquiring on-orbit beam pointing information of spaceborne antennas using distributed multi-star sensors, and in particular, to a method and system for acquiring on-orbit beam pointing information of spaceborne radar antennas using on-board distributed multi-star sensors. Background Technology

[0002] Synthetic Aperture Radar (SAR) is an active Earth observation system that can be installed on aircraft, satellites, and other flight platforms to conduct all-weather, 24 / 7 Earth observation. Due to its unique advantages in applications such as disaster monitoring, environmental monitoring, ocean observation, and resource exploration, it is receiving increasing attention from countries worldwide. Especially with the rapid development of aerospace technology in recent years, SAR is increasingly being used in spaceborne Earth observation, leading to the emergence of various forms of spaceborne radar antennas, including planar phased arrays and reflectors. Regardless of whether it's a planar phased array or a reflector, the basic working principle of a spaceborne radar antenna is to transmit directional microwaves towards a predetermined target and receive the echo to image that target. Therefore, improving the accuracy of the microwave beam pointing emitted by the spaceborne radar antenna can significantly reduce the deviation angle between the beam pointing and the expected pointing, enhance the radiation intensity of the predetermined target, and improve observation and imaging performance. In practical engineering applications, the pointing of the microwave beam emitted by the radar antenna in the satellite's orbital system is usually defined as the on-orbit beam pointing. Currently, satellites typically use star sensors as attitude measurement and control sensors to observe and acquire the satellite's attitude status in orbit. Since the radar antenna is fixed to the satellite, the attitude of the satellite observed by the star sensor is also the attitude of the radar antenna. Therefore, as long as the beam pointing information of the radar antenna in the star sensor observation coordinate system is obtained, and then the transformation relationship between the star sensor observation coordinate system and the orbital system is used, the description of the radar antenna beam pointing in the orbital system can be obtained.

[0003] Existing phased array or reflector-type spaceborne radar antennas require deployment mechanisms after entering orbit to form a complete antenna. During this process, the vibration environment during satellite launch, the deployment mechanism, and the orbital space environment all affect the microwave beam pointing of the radar antenna, causing a deviation between the on-orbit beam pointing and the beam pointing obtained from ground tests. This, in turn, affects the actual performance of the radar antenna during its on-orbit operation. Current research and engineering practices primarily focus on improving the mechanical performance of the radar antenna to control its shape and position accuracy, minimizing the impact of the launch process and on-orbit environment on its mechanical performance, and ultimately using beam pointing information obtained from ground tests to replace the on-orbit beam pointing information.

[0004] For example, Chinese invention patent document CN105444669A discloses a measurement system and method for measuring the pointing change of a large plane, including a linear laser emitter, one-dimensional PSD measurement points, a measurement controller, and an information processor. The information processor is data-connected to the measurement controller, and the measurement controller is control-connected to the linear laser emitter. There are multiple one-dimensional PSD measurement points, each equipped with a one-dimensional PSD sensor. The light output from the linear laser emitter is transmitted to the one-dimensional PSD sensor, which is data-connected to the measurement controller. The multiple one-dimensional PSD measurement points are arranged on a large plane. The document also provides a measurement method for the above-mentioned measurement system. This method uses a linear laser combined with one-dimensional PSD sensing technology to obtain the positional change of each measurement point and solve for the pointing change of the large plane, allowing for further adjustment or compensation of the large plane.

[0005] Chinese invention patent application CN105526879A discloses an on-orbit measurement system and method for the deformation of a large satellite antenna based on fiber Bragg gratings. The system includes a light generator, a transmission fiber, multiple grating measurement points, a demodulator, and an information processor, all connected sequentially via a transmission fiber. The light generator comprises a main light source and a beam splitter to provide the light waves required for multiple transmission fibers. Multiple grating measurement points are arranged on the surface of the large satellite antenna to form a sensing network. The demodulator demodulates the collected light waves to obtain the strain and temperature of each grating measurement point. The information processor calculates the strain and temperature of each grating measurement point to obtain the antenna array surface deformation parameters. This invention also provides an on-orbit measurement method for the deformation of a large satellite antenna based on fiber Bragg gratings, facilitating antenna structure control or signal compensation and improving the anti-interference performance of satellite imaging.

[0006] Chinese invention patent document CN107121124A discloses a method for measuring the mechanical pointing accuracy of a spaceborne antenna. This method utilizes a camera to photograph the antenna array to quickly obtain the coordinates of reflective marker points. These coordinates are then converted to the coordinate system of a theodolite measurement system using common marker points, and the antenna array normal is fitted. The theodolite is then used to collimate and measure the satellite reference prism. The angular relationship between the theodolites is obtained through mutual aiming, and finally, the mechanical pointing accuracy of the antenna array normal relative to the satellite coordinate system is calculated. This method meets the requirements for rapid measurement of the mechanical pointing accuracy of large-size antennas. The method described in this document is widely applicable to the measurement of antenna mechanical pointing accuracy, especially for the rapid measurement of the mechanical pointing accuracy of large-size antennas.

[0007] The methods disclosed in the aforementioned patents are all only for planar phased array antennas. They measure the mechanical positioning accuracy of the antenna and ultimately obtain only the mechanical pointing information of the antenna. This is an indirect, approximate equivalent way of obtaining beam pointing information.

[0008] For example, for radar antennas with reflector surfaces, Chinese invention patent application CN104236518A discloses a method for detecting the main beam pointing of an antenna based on optical imaging and pattern recognition. The method includes the following steps: Step 1: A wide field-of-view visible light camera images the target, capturing, identifying, and tracking the target; Step 2: The wide field-of-view visible light camera guides a small field-of-view visible light camera to align with the target for high-resolution imaging; Step 3: The target antenna region is determined using a random ellipse detection method; Step 4: The main beam pointing of the target antenna is determined using a spatial circle normal vector determination method. This paper solves the problem of detecting the main beam pointing of a space target antenna by using a small field-of-view visible light camera for high-resolution detection of the target antenna and employing pattern recognition technology to detect the target antenna region and determine the main beam pointing of the target antenna, thereby providing guidance for navigation, guidance, and control systems.

[0009] Chinese invention patent CN103185566A discloses a testing device and method for beam pointing of a reflector antenna. The reflector antenna is fixed to an antenna support and includes an electronic theodolite and an antenna reference mirror. The device also includes an optical telescope. The optical telescope is fixed to the antenna support parallel to the mechanical axis of the reflector antenna. A target is placed next to the transmitting antenna. This testing device is used to accurately measure the angle between the electrical axis and mechanical axis of the reflector antenna by combining optical measurement methods and antenna far-field pattern testing. This method utilizes an optical telescope fixed to the antenna support parallel to the mechanical axis of the reflector antenna, and a target is placed next to the transmitting antenna. Finally, the angle between the electrical axis and mechanical axis of the reflector antenna is accurately measured by combining optical measurement methods and antenna far-field pattern testing. This document can solve the problem of accurately testing the electrical and mechanical axis pointing of spaceborne antennas, and has the advantages of accuracy and versatility. However, this document still discloses a ground-based testing method, specifically a shape and position measurement of the reflector antenna, using the mechanical pointing of the reflector antenna instead of microwave beam pointing, which is also an indirect, approximately equivalent form of obtaining beam pointing information.

[0010] Chinese invention patent application CN108152787A discloses a method for accurately obtaining the beam pointing of a satellite radar antenna. The method involves: (1) a radar satellite equipped with a microwave beam receiving antenna, through which the radar beam pointing information is accurately obtained using the receiving antenna and onboard processing equipment; (2) a radar satellite equipped with a laser transmitter, and simultaneously with the receiving antenna obtaining microwave beam information, the laser transmitter emits a laser beam that enters the onboard star sensor's photosensitive element; (3) through the star sensor's computational processing, the inertial pointing of the aforementioned laser beam is obtained; (4) the microwave beam pointing information, the laser beam inertial pointing information, and the satellite attitude information obtained by the star sensor are fused and processed to accurately obtain the relationship between the star sensor's optical axis pointing and the microwave beam pointing, thereby enabling precise correction of the microwave beam pointing during radar imaging. This paper, through the conversion between onboard optical references and microwave electrical references, directly converts the microwave beam pointing information to a description in the satellite's attitude coordinate system, accurately obtaining the on-orbit beam pointing information. This document discloses a method for obtaining conversion relationships using a laser and a star sensor. However, it is well known that the night sky is a relatively dark background. Using a laser on a satellite and directing this strong light source into the star sensor, which then detects and obtains the beam's direction and position, will inevitably affect the star sensor's normal observation of the night sky, thus impacting the system's measurement accuracy. Furthermore, stray light from space, such as sunlight, moonlight, and atmospheric radiation, can easily interfere with the laser beam. Therefore, the method disclosed in this document has significant limitations.

[0011] Regarding the aforementioned existing technologies, the inventors believe that the vibration environment, deployment mechanism, and orbital space environment during the satellite launch phase will all affect the microwave beam pointing of the radar antenna, causing a deviation between the on-orbit beam pointing of the radar antenna and the beam pointing obtained from ground testing. This, in turn, affects the actual performance of the radar antenna during its on-orbit operation, making it difficult to accurately obtain the on-orbit beam pointing information of the radar antenna, and thus has certain limitations. Summary of the Invention

[0012] To address the shortcomings of existing technologies, the purpose of this invention is to provide a method and system for acquiring pointing information of spaceborne antennas using distributed multi-star sensors.

[0013] A method for acquiring satellite-borne antenna pointing information using distributed multi-star sensors according to the present invention is characterized by comprising the following steps:

[0014] Equipment steps: The satellite is equipped with a radar antenna, platform star sensor, measurement antenna, and measurement star sensor;

[0015] First transformation relationship acquisition step: Establish the measurement star-sensor observation coordinate system and the measurement antenna coordinate system, and obtain the transformation relationship between the measurement star-sensor observation coordinate system and the measurement antenna coordinate system according to the relationship between the measurement antenna and the measurement star-sensor, which is denoted as the first transformation relationship;

[0016] The second conversion relationship acquisition step: By performing two-way microwave transmission and reception between the measurement antenna and the radar antenna, the conversion relationship between the radar antenna beam pointing information and the measurement antenna coordinate system is obtained and denoted as the second conversion relationship;

[0017] The third transformation relationship acquisition step: While the second transformation relationship acquisition step is being carried out, the measuring star sensor and the platform star sensor simultaneously observe stars and match them with the same star map to obtain the transformation relationship between the platform star sensor observation coordinate system and the measuring star sensor observation coordinate system, which is denoted as the third transformation relationship;

[0018] Fusion and transformation steps: Using the first transformation relationship, the second transformation relationship, and the third transformation relationship, perform fusion and transformation according to the formula to obtain the radar antenna beam pointing information in the platform star-sensitive observation coordinate system.

[0019] Preferably, in the first conversion relationship acquisition step, there is a fixed relative positional relationship between the measuring antenna and the measuring star sensor, and there is a fixed spatial angle relationship between the direction of the microwave beam emitted by the measuring antenna and the direction of the optical axis of the measuring star sensor. The conversion relationship between the measuring star sensor coordinate system and the measuring antenna coordinate system is obtained through the fixed relative positional relationship and the fixed spatial angle relationship.

[0020] Preferably, in the second conversion relationship acquisition step, the measuring antenna and the radar antenna perform bidirectional microwave transmission and reception to acquire the microwave beam pointing information emitted by the radar antenna in the measuring antenna coordinate system.

[0021] Preferably, in the third transformation relationship acquisition step, the measurement star sensor and the platform star sensor simultaneously observe stars in space and match them with the same star map, respectively acquiring the attitude quaternions of the platform star sensor observation coordinate system and the measurement star sensor observation coordinate system relative to the inertial frame, as well as the transformation relationship from the inertial frame to the platform star sensor observation coordinate system and the measurement star sensor observation coordinate system, and acquiring the transformation relationship between the platform star sensor observation coordinate system and the measurement star sensor observation coordinate system.

[0022] Preferably, in the configuration step, the measurement antenna includes a beam pointing measurement antenna, and the measurement star sensor includes a star sensor for beam pointing measurement.

[0023] A system for acquiring satellite-borne antenna pointing information using distributed multi-star sensors, according to the present invention, includes the following modules:

[0024] Equipped modules: The satellite is equipped with a radar antenna, platform star sensor, measurement antenna, and measurement star sensor;

[0025] First transformation relationship acquisition module: Establish the measurement star-sensor observation coordinate system and the measurement antenna coordinate system, and obtain the transformation relationship between the measurement star-sensor observation coordinate system and the measurement antenna coordinate system according to the relationship between the measurement antenna and the measurement star-sensor, which is denoted as the first transformation relationship;

[0026] The second conversion relationship acquisition module: through the two-way microwave transmission and reception between the measurement antenna and the radar antenna, the conversion relationship between the radar antenna beam pointing information and the measurement antenna coordinate system is acquired and denoted as the second conversion relationship;

[0027] Third transformation relationship acquisition module: Simultaneously with the second transformation relationship acquisition module, the measurement star sensor and the platform star sensor synchronously observe stars and match them with the same star map to obtain the transformation relationship between the platform star sensor observation coordinate system and the measurement star sensor observation coordinate system, which is denoted as the third transformation relationship;

[0028] Fusion and transformation module: Using the first transformation relationship, the second transformation relationship, and the third transformation relationship, the module performs fusion and transformation according to the formula to obtain the radar antenna beam pointing information in the platform star-sensitive observation coordinate system.

[0029] Preferably, in the first conversion relationship acquisition module, there is a fixed relative positional relationship between the measuring antenna and the measuring star sensor, and there is a fixed spatial angle relationship between the direction of the microwave beam emitted by the measuring antenna and the direction of the optical axis of the measuring star sensor. The conversion relationship between the coordinate system of the measuring star sensor and the coordinate system of the measuring antenna is obtained through the fixed relative positional relationship and the fixed spatial angle relationship.

[0030] Preferably, in the second conversion relationship acquisition module, the measuring antenna and the radar antenna perform bidirectional microwave transmission and reception to acquire the microwave beam pointing information emitted by the radar antenna in the measuring antenna coordinate system.

[0031] Preferably, in the third transformation relationship acquisition module, the measurement star sensor and the platform star sensor simultaneously observe stars in space and match them with the same star map, respectively acquiring the attitude quaternions of the platform star sensor observation coordinate system and the measurement star sensor observation coordinate system relative to the inertial frame, as well as the transformation relationship from the inertial frame to the platform star sensor observation coordinate system and the measurement star sensor observation coordinate system, and acquiring the transformation relationship between the platform star sensor observation coordinate system and the measurement star sensor observation coordinate system.

[0032] Preferably, in the equipped module, the measurement antenna includes a beam pointing measurement antenna, and the measurement star sensor includes a star sensor for beam pointing measurement.

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

[0034] 1. This method cleverly utilizes the unified and constant reference of celestial stars. While in orbit, it simultaneously observes stars using star sensors (platform star sensors and measurement star sensors) distributed at different locations on the satellite and matches the observation results with the same star map. This allows for the acquisition of the satellite's current attitude (using platform star sensor observation results) and the attitude of the measurement star sensors (using measurement star sensor observation results), respectively. Through this process, the transformation relationship between the measurement star sensor observation coordinate system and the platform star sensor observation coordinate system is obtained, laying the foundation for subsequent fusion and transformation.

[0035] 2. This method utilizes bidirectional microwave transmission and reception between the measurement antenna and the radar antenna to directly acquire the radar antenna beam pointing information. This information is then transformed into the measurement antenna coordinate system for description. This direct acquisition of radar antenna beam pointing information is fundamentally different from traditional indirect methods that obtain the mechanical pointing of the radar antenna array and approximate it as the microwave beam pointing emitted by the radar antenna. Furthermore, this method, by directly employing bidirectional microwave transmission and reception between the measurement antenna and the radar antenna, is not limited by the radar antenna's structure or configuration. It is applicable to various types of radar antennas, such as planar phased arrays and reflectors, demonstrating strong versatility.

[0036] 3. This invention ingeniously establishes a relatively fixed spatial installation position relationship between the measurement antenna and the measurement star sensor, and a relatively fixed spatial angle relationship between the microwave beam vector emitted by the measurement antenna and the optical axis vector of the measurement star sensor. Through this relatively fixed installation position and spatial angle relationship, the transformation relationship between the measurement star sensor observation coordinate system and the measurement antenna coordinate system can be obtained. Furthermore, utilizing the obtained radar antenna microwave beam emission pointing information in the measurement antenna coordinate system, and the transformation relationship between the measurement star sensor observation coordinate system and the platform star sensor observation coordinate system, the radar antenna microwave beam emission pointing information is transformed to be described in the platform star sensor observation coordinate system. Through this fusion transformation process, the high-precision attitude measurement component of the satellite star sensor is fully utilized to achieve "optical-electric" reference conversion between the optical observation of the platform star sensor and the measurement star sensor and the microwave beam emission pointing of the radar antenna, ensuring the accuracy of the entire fusion transformation. Attached Figure Description

[0037] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0038] Figure 1 This is a schematic diagram of the present invention to highlight the positional and spatial angular relationships of the measurement antenna and measurement star sensor equipped on the satellite, the microwave bidirectional transmission-reception relationship between the measurement antenna and the radar antenna, and the synchronous observation of stars in space by the measurement star sensor and the platform star sensor.

[0039] Figure 2 This is a flowchart of the method for acquiring on-orbit beam pointing information of a spaceborne radar antenna using distributed multi-star sensors, as described in this invention. Detailed Implementation

[0040] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the scope of protection of the present invention.

[0041] This invention discloses a method for acquiring on-orbit beam pointing information of a spaceborne radar antenna using on-board distributed multi-star sensors, such as... Figure 1 and Figure 2 As shown, it includes the following steps:

[0042] Preparation steps:

[0043] Step 1: The satellite is equipped with a radar antenna (denoted as Rad), a platform star sensor (denoted as F), a measurement antenna (denoted as p), and a measurement star sensor (denoted as N). The measurement antenna includes a beam pointing measurement antenna, and the measurement star sensor includes a star sensor used for beam pointing measurement.

[0044] Obtaining transformation relations 1, 2, and 3:

[0045] Step 2: Establish the star-sensitive observation coordinate system (denoted as S). N The N-frame (abbreviated as N-frame) and the measurement antenna coordinate system (denoted as r-frame) p (abbreviated as p-system), based on the relationship between the measuring antenna and the measuring star sensor, the transformation relationship between the measuring star sensor observation coordinate system and the measuring antenna coordinate system is obtained (denoted as R). N←p ).

[0046] The star-sensor observation coordinate system (N-system) and the measurement antenna coordinate system (P-system) are both Cartesian coordinate systems, conforming to the right-hand screw rule. The Z-axis of the star-sensor observation coordinate system is the direction of the star-sensor optical axis, and the X-axis is the star-sensor horizontal axis. The Z-axis of the measurement antenna coordinate system is the direction of the measurement antenna beam vector, and the X-axis and Y-axis are preset according to the antenna geometry.

[0047] Because the measuring antenna and the measuring star have a relatively fixed spatial installation position relationship, and the microwave beam vector emitted by the measuring antenna has a relatively fixed spatial angle relationship with the optical axis vector of the measuring star, the transformation relationship R between the measuring star's observation coordinate system and the measuring antenna's coordinate system can be obtained through this relatively fixed installation position relationship and spatial angle relationship. N←p .

[0048] Step 3: By performing bidirectional microwave transmission and reception between the measurement antenna and the radar antenna, obtain the microwave beam pointing information emitted by the radar antenna in the measurement antenna coordinate system (the radar antenna beam pointing information is denoted as r). Rad Rad vector (abbreviated as r) is also known as r Rad With r p Transformation relation R p←Rad The measurement antenna and the radar antenna perform bidirectional microwave transmission and reception, which includes microwave transmission from the radar antenna to the measurement antenna and reception by the measurement antenna, and microwave transmission from the measurement antenna to the radar antenna and reception by the radar antenna.

[0049] Among them, the radar antenna beam pointing (Rad vector) is the antenna beam pointing vector, which is the quantity to be acquired.

[0050] Step 4: Simultaneously with Step 3, measure the stars in space simultaneously with the platform star-sensor and match them with the same star map to obtain the platform star-sensor observation coordinate system (denoted as S). F The F-frame (abbreviated as F-frame) and the relative inertial frame (denoted as S-frame) of the star-sensitive observation coordinate system. i The attitude quaternions of the inertial frame (i-frame, abbreviated as i-frame). The transformation relationships from the inertial frame (i-frame) to the platform star-sensitive observation coordinate system and the measurement star-sensitive observation coordinate system are R... F←i and R N←i Finally, the relationship between the transformations of the platform star-sensitive observation coordinate system (F system) and the measurement star-sensitive observation coordinate system (N system) is obtained as R. F←N =R F←i *R N←i T , where T represents transpose.

[0051] During in-orbit operation, the platform star-sensor and the measurement star-sensor simultaneously observe stars in space and match them with the same star map to obtain their respective observation data. Using the observation data from the platform star-sensor and the measurement star-sensor, the current attitude status of the satellite and the measurement star-sensor can be obtained, and thus the transformation relationship between the measurement star-sensor observation coordinate system and the platform star-sensor observation coordinate system can be determined.

[0052] Fusion and conversion steps:

[0053] Step 5: Use the transformation relationship R between the measurement star-sensor observation coordinate system and the measurement antenna coordinate system obtained in Step 2. N←p Step 3: Obtain the radar antenna beam pointing information R in the measurement antenna coordinate system. p←Rad Step 4: Obtain the relationship between the changes in the acquisition platform's star-sensitive F-system and the measurement star-sensitive N-system. F←N The radar antenna beam pointing information (denoted as R) in the platform's star-sensitive observation coordinate system is obtained by performing a fusion transformation according to the following formula. F←Rad ).

[0054] R F←Rad =R F←N *R N←p T *R p←Rad

[0055] Step 6:

[0056] Based on step 4 above, the orbital system (denoted as S) is further obtained. O The attitude matrix under the O-series (obtained through platform star-sensor observations) is denoted as R. O←F .

[0057] R O←F =R O←i *R F←i T

[0058] The radar beam pointing information in the platform star-sensitive observation coordinate system obtained in step 5 is further transformed into the orbital system (O system), denoted as R. O←Rad .

[0059] R O←Rad =R O←F *R F←Rad

[0060] This method cleverly utilizes the unified and constant benchmark of cosmic stars. It employs distributed platform star sensors to simultaneously observe stars and match them with the same star map, establishing a transformation relationship between star sensors located at different positions on the satellite (i.e., a transformation relationship between platform star sensors and observation star sensors). Then, combining the two-way microwave transmission and reception between the measurement antenna and the measurement star sensors, and between the measurement antenna and the radar antenna, which have fixed relative positional and spatial angular relationships, the microwave beam pointing information emitted by the radar antenna in the measurement antenna coordinate system is transformed into a description in the platform star sensor observation coordinate system. The microwave beam pointing information emitted by the radar antenna is described as the radar antenna microwave beam pointing vector in the satellite platform star sensor observation coordinate system. Finally, through the transformation relationship between the star sensor observation coordinate system and the orbital system, the radar antenna beam pointing information in the orbital system is obtained.

[0061] The present invention also provides a system for acquiring satellite antenna pointing information using distributed multi-star sensors. The system for acquiring satellite antenna pointing information using distributed multi-star sensors can be implemented by executing the process steps of the method for acquiring satellite antenna pointing information using distributed multi-star sensors. That is, those skilled in the art can understand the method for acquiring satellite antenna pointing information using distributed multi-star sensors as a preferred embodiment of the system for acquiring satellite antenna pointing information using distributed multi-star sensors.

[0062] This invention also provides a system for acquiring satellite-borne antenna pointing information using distributed multi-star sensors, comprising the following modules:

[0063] Equipped Modules: The satellite is equipped with a radar antenna, a platform star sensor, a measurement antenna, and a measurement star sensor. The measurement antenna includes a beam pointing measurement antenna, and the measurement star sensor includes a star sensor for beam pointing measurement.

[0064] The first transformation relationship acquisition module: Establishes a measurement star-sensor observation coordinate system and a measurement antenna coordinate system. Based on the relationship between the measurement antenna and the measurement star-sensor, it acquires the transformation relationship between the measurement star-sensor observation coordinate system and the measurement antenna coordinate system, denoted as the first transformation relationship. The measurement antenna and the measurement star-sensor have a fixed relative positional relationship, and the direction of the microwave beam emitted by the measurement antenna has a fixed spatial angular relationship with the optical axis of the measurement star-sensor. The transformation relationship between the measurement star-sensor coordinate system and the measurement antenna coordinate system is obtained through this fixed relative positional relationship and fixed spatial angular relationship.

[0065] The second conversion relationship acquisition module: This module acquires the conversion relationship between the radar antenna beam pointing information and the measurement antenna coordinate system through bidirectional microwave transmission and reception between the measurement antenna and the radar antenna. This relationship is denoted as the second conversion relationship. The measurement antenna and the radar antenna perform bidirectional microwave transmission and reception to acquire the microwave beam pointing information emitted by the radar antenna in the measurement antenna coordinate system.

[0066] The third transformation relationship acquisition module: Simultaneously with the second transformation relationship acquisition module, the measurement star sensor and the platform star sensor synchronously observe stars and match them with the same star map to obtain the transformation relationship between the platform star sensor observation coordinate system and the measurement star sensor observation coordinate system, denoted as the third transformation relationship. The measurement star sensor and the platform star sensor synchronously observe stars in space and match them with the same star map to obtain the attitude quaternions of the platform star sensor observation coordinate system and the measurement star sensor observation coordinate system relative to the inertial frame, as well as the transformation relationship from the inertial frame to the platform star sensor observation coordinate system and the measurement star sensor observation coordinate system, thus obtaining the transformation relationship between the platform star sensor observation coordinate system and the measurement star sensor observation coordinate system.

[0067] Fusion and transformation module: Using the first transformation relationship, the second transformation relationship, and the third transformation relationship, the module performs fusion and transformation according to the formula to obtain the radar antenna beam pointing information in the platform star-sensitive observation coordinate system.

[0068] Those skilled in the art will understand that, besides implementing the system and its various devices, modules, and units provided by this invention in the form of purely computer-readable program code, the same functions can be achieved entirely through logical programming of the method steps, making the system and its various devices, modules, and units of this invention function in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, and embedded microcontrollers. Therefore, the system and its various devices, modules, and units provided by this invention can be considered as a hardware component, and the devices, modules, and units included therein for implementing various functions can also be considered as structures within the hardware component; alternatively, the devices, modules, and units for implementing various functions can be considered as both software modules implementing the method and structures within the hardware component.

[0069] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A method for acquiring pointing information of a spaceborne antenna using distributed multi-star sensors, characterized in that, Includes the following steps: Equipment steps: The satellite is equipped with a radar antenna, platform star sensor, measurement antenna, and measurement star sensor; First transformation relationship acquisition step: Establish the measurement star-sensor observation coordinate system and the measurement antenna coordinate system, and obtain the transformation relationship between the measurement star-sensor observation coordinate system and the measurement antenna coordinate system according to the relationship between the measurement antenna and the measurement star-sensor, which is denoted as the first transformation relationship; The second conversion relationship acquisition step: By performing two-way microwave transmission and reception between the measurement antenna and the radar antenna, the conversion relationship between the radar antenna beam pointing information and the measurement antenna coordinate system is obtained and denoted as the second conversion relationship; The third transformation relationship acquisition step: While the second transformation relationship acquisition step is being carried out, the measuring star sensor and the platform star sensor simultaneously observe stars and match them with the same star map to obtain the transformation relationship between the platform star sensor observation coordinate system and the measuring star sensor observation coordinate system, which is denoted as the third transformation relationship; Fusion and transformation steps: Using the first transformation relationship, the second transformation relationship, and the third transformation relationship, perform fusion and transformation according to the formula to obtain the radar antenna beam pointing information in the platform star-sensitive observation coordinate system; In the first conversion relationship acquisition step, there is a fixed relative positional relationship between the measuring antenna and the measuring star sensor, and there is a fixed spatial angle relationship between the microwave beam emitted by the measuring antenna and the optical axis of the measuring star sensor. The conversion relationship between the measuring star sensor coordinate system and the measuring antenna coordinate system is obtained through the fixed relative positional relationship and the fixed spatial angle relationship. In the second conversion relationship acquisition step, the measuring antenna and the radar antenna perform bidirectional microwave transmission and reception to acquire the microwave beam pointing information emitted by the radar antenna in the measuring antenna coordinate system. In the third transformation relationship acquisition step, the measurement star sensor and the platform star sensor synchronously observe stars in space and match them with the same star map. The attitude quaternions of the platform star sensor observation coordinate system and the measurement star sensor observation coordinate system relative to the inertial frame, as well as the transformation relationship from the inertial frame to the platform star sensor observation coordinate system and the measurement star sensor observation coordinate system, are obtained respectively. Then, the transformation relationship between the platform star sensor observation coordinate system and the measurement star sensor observation coordinate system is obtained.

2. The method for acquiring satellite-borne antenna pointing information using distributed multi-star sensors according to claim 1, characterized in that, In the configuration step, the measurement antenna includes a beam pointing measurement antenna, and the measurement star sensor includes a star sensor for beam pointing measurement.

3. A system for acquiring pointing information of a spaceborne antenna using distributed multi-star sensors, characterized in that, Includes the following modules: Equipped modules: The satellite is equipped with a radar antenna, platform star sensor, measurement antenna, and measurement star sensor; First transformation relationship acquisition module: Establish the measurement star-sensor observation coordinate system and the measurement antenna coordinate system, and obtain the transformation relationship between the measurement star-sensor observation coordinate system and the measurement antenna coordinate system according to the relationship between the measurement antenna and the measurement star-sensor, which is denoted as the first transformation relationship; The second conversion relationship acquisition module: through the two-way microwave transmission and reception between the measurement antenna and the radar antenna, the conversion relationship between the radar antenna beam pointing information and the measurement antenna coordinate system is acquired and denoted as the second conversion relationship; Third transformation relationship acquisition module: Simultaneously with the second transformation relationship acquisition module, the measurement star sensor and the platform star sensor synchronously observe stars and match them with the same star map to obtain the transformation relationship between the platform star sensor observation coordinate system and the measurement star sensor observation coordinate system, which is denoted as the third transformation relationship; Fusion and transformation module: Using the first transformation relationship, the second transformation relationship, and the third transformation relationship, the module performs fusion and transformation according to the formula to obtain the radar antenna beam pointing information in the platform star-sensitive observation coordinate system; In the first conversion relationship acquisition module, there is a fixed relative positional relationship between the measuring antenna and the measuring star sensor, and there is a fixed spatial angle relationship between the microwave beam emitted by the measuring antenna and the optical axis of the measuring star sensor. The conversion relationship between the measuring star sensor coordinate system and the measuring antenna coordinate system is obtained through the fixed relative positional relationship and the fixed spatial angle relationship. In the second conversion relationship acquisition module, the measuring antenna and the radar antenna perform bidirectional microwave transmission and reception to acquire the microwave beam pointing information emitted by the radar antenna in the measuring antenna coordinate system; In the third transformation relationship acquisition module, the measurement star sensor and the platform star sensor synchronously observe stars in space and match them with the same star map. The attitude quaternions of the platform star sensor observation coordinate system and the measurement star sensor observation coordinate system relative to the inertial frame are obtained respectively, as well as the transformation relationship from the inertial frame to the platform star sensor observation coordinate system and the measurement star sensor observation coordinate system. The transformation relationship between the platform star sensor observation coordinate system and the measurement star sensor observation coordinate system is also obtained.

4. The system for acquiring satellite antenna pointing information using distributed multi-star sensors according to claim 3, characterized in that, In the equipped module, the measurement antenna includes a beam pointing measurement antenna, and the measurement star sensor includes a star sensor for beam pointing measurement.

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