CN113048975A

CN113048975A - Subaperture array interference star sensor

Info

Publication number: CN113048975A
Application number: CN202110325926.8A
Authority: CN
Inventors: 郝云彩
Original assignee: Beijing Institute of Control Engineering
Current assignee: Beijing Institute of Control Engineering
Priority date: 2021-03-26
Filing date: 2021-03-26
Publication date: 2021-06-29
Anticipated expiration: 2041-03-26
Also published as: CN113048975B

Abstract

The invention relates to a sub-aperture array interference imaging star sensor, which can be applied to the technical fields of spacecraft attitude measurement and rotation angular rate measurement. The sub-hole array interferometric star sensor proposed by the present invention converts the image formed by a star into a star point cluster containing multiple star points, increases the number of sampling samples for star point positioning, and makes the positioning of a single star point random. Error reduction for the prior art

Star point positioning accuracy improved

times, so that the highest precision level of the star sensor in the prior art can be raised from 0.1" to more than 0.01", which greatly improves the performance of the star sensor. The invention is suitable for all application occasions where the point-shaped target imaging positioning with the viewing angle is not greater than 1°.

Description

Subaperture array interference star sensor

Technical Field

The invention relates to a subaperture array interference imaging star sensor which can be applied to the technical field of spacecraft attitude measurement and rotation angular rate measurement.

Background

At present, a star sensor is often used for measuring the attitude of a spacecraft, and the sensor has the main principle that: the method comprises the steps of obtaining a star map by photoelectric imaging of a fixed star in an area of a sky according to the principle that the position of the fixed star is basically motionless relative to an inertial space, processing and identifying the star map to obtain the direction of an optical axis of a measuring sensor in the inertial space, and converting the star sensor in a spacecraft installation coordinate system and a spacecraft attitude coordinate system to obtain the three-axis attitude of the spacecraft.

In the prior art, the star sensor hardware includes a light shield, an optical system (lens), an electronic system, an electrical appliance, a structural interface, star map processing and attitude calculation software. The electronic system comprises a detector imaging component, an information processing unit, a power supply module and internal and external electric connections, and the star atlas processing and attitude calculation software mainly comprises a star atlas preprocessing module, a star atlas matching module, an attitude calculation module, a communication module and the like. The main technical indexes of the star sensor comprise three-axis angle measurement precision, data updating rate, stray light inhibition capability and the like, and the precision index of the star sensor is a core technical index of the star sensor and represents the pointing error of an optical axis of the star sensor. In the prior art, a transmission type optical system is generally adopted in the star sensor optical system, and a design scheme of refraction and diffraction is adopted in the transmission type optical system. Although the catadioptric or reflective optical system is researched by researchers, the catadioptric or reflective optical system is rarely applied to star sensor products really, and is generally adopted only for ultra-high-precision or ultra-high-precision star sensors (the precision is better than 0.5 arc second).

No matter which star sensor optical system exists, the mutual constraint relation among the relative aperture, the field angle, the focal length and the imaging quality exists, and the constraint relation also exists between the parameters and the measurement precision of the star sensor. Generally, the measurement accuracy of the star sensor depends on the integration of single-star positioning accuracy and multi-star statistical accuracy, which is theoretically equal to the product of single-star positioning accuracy and the square root of the number of captured navigation stars, so how to improve the single-star positioning accuracy and the number of captured navigation stars becomes a main way for improving the accuracy of the star sensor, the single-star positioning accuracy depends on the product of the instantaneous field of view of star points and the star point extraction accuracy, and the number of captured navigation stars is related to the aperture and the field angle of the star sensor and the detection sensitivity. In the technical field of ultra-high precision star sensors, a catadioptric or reflective optical system is generally adopted, and the purpose of improving the positioning precision of a single star is mainly realized by adopting a long focal length and a small visual field. Although the design can solve the problem of the scheme of the existing ultra-high-precision star sensor, the design also brings the following defects.

The prior art mainly has the following defects:

(1) the imaging structure of a catadioptric optical system adopted by the existing ultra-high precision star sensor (the precision is 0.1' -magnitude) causes a problem of larger weight, and like products are generally over 10 kg.

(2) The quantity of fixed stars captured by a single star map of the star sensor is limited due to the restriction relation among the relative aperture, the field angle, the focal length and the imaging quality, and the accuracy is further improved.

(3) The stray light eliminating of the existing ultra-high precision star sensor adopts a conventional single-aperture light shield, so that the length and the weight are relatively large.

(4) The maximum precision level of the existing star sensor is not stopped before the precision threshold hysteresis effect of the existing star sensor is in the order of ten seconds (0.1 '), and the data acquisition of more scientific tasks in the future needs to be supported by precision orientation precision of centiseconds (0.01'), or above, and needs to be solved innovatively. Many scientific tasks require extremely high-precision orientation and navigation data, such as an ultra-large scale space-to-ground mapping satellite, a distributed satellite space relative attitude and position maintenance, space laser aiming, deep sea and global long-endurance flight astronomical navigation and the like, and the higher the precision of a star sensor is, the higher the precision of orientation and navigation is. The main reasons of the threshold hysteresis effect are that error sources such as imaging instability, imaging point non-ideal Gaussian distribution, detector geometry and response nonuniformity caused by inherent noise, temperature field nonuniformity and the like of an instrument detector cannot be eliminated, wherein an error showing high-frequency characteristics is called a high-frequency error (such as a white noise error), an error showing low-frequency characteristics is called a low-frequency error (such as a temperature error), the method for eliminating the errors at present has two types, namely an inner type and an outer type, the inner type is ensured by design performance and device material refinement, the outer type is calibrated, the single star position extraction precision is improved, and the number of navigation star points is increased to reduce the overall error level. Although an improvement in accuracy can also be obtained from the innovations in calibration methods and calibration equipment, this improvement is also subject to a threshold effect of 0.1 ″ due to calibration instrument error limitations. The improvement of the single-star position extraction precision is influenced by high-frequency and low-frequency errors, a certain threshold value is generally difficult to exceed, and the measured value of an actual product is about 0.1 pixel mostly, although the measured value can reach 0.01 pixel theoretically. The number of navigation stars depends on the field of view and detection sensitivity of the star sensor, and the improvement of the average number of the navigation stars is limited according to the existing principle.

In summary, the highest accuracy level that the existing star sensor can achieve is still in the order of minutes and seconds (0.1'), the star sensor under the existing principle has the sunlight stray light inhibition angle design capability of about 30 degrees under the constraint of reasonable limited length and caliber, the performance threshold hysteresis effect occurs, and the sunlight stray light inhibition capability of about 20 degrees is obtained under the same size and performance in the future so as to adapt to the acquisition of scientific measurement data of the sun-facing working condition, so the principle needs to be innovated. At present, the sun suppression angle of the international star sensor is designed at the best level to be about 30 degrees, which can be said to be a performance threshold hysteresis effect limited by the existing design level and material process. In order to ensure the normal work of the tracker, the position relation between the orbit surface of the spacecraft and the sun in the whole period needs to be limited, and the installation position and the orientation of the spacecraft need to be limited, so that a proper installation mode is difficult to find for some complex tasks. In the future, the wide-area motion carrier in land, sea, air and sky has special requirements on the stray light eliminating capacity, for example, a task requires that the star sensor works towards the sun, the solar suppression angle is not more than 25 degrees, the prior art and the prior principle are difficult to achieve, and the stray light suppression angle performance threshold hysteresis effect of the prior principle must be broken through.

In the star sensor under the existing principle, the inherent restriction relation of the trade-off length exists between each parameter and the technical index, the index full-optimization cannot be realized, generally, optimization can be chosen only according to the constraint relation, and the principle innovation is needed to break through the constraint relation in order to obtain the index parameter of the full-optimization.

The pointing accuracy of the star sensor under the existing principle depends on the positioning accuracy of a single star and the number of tracking fixed stars, the number of navigation stars needs to be increased by adopting multi-star adjustment to improve the accuracy, the increase of the number of stars means that the view field is increased or the detection sensitivity is increased, the size of a detector limits, the focal length is reduced by increasing the view field, the accuracy of a single pixel is reduced, the accuracy improvement effect caused by the multi-star adjustment is overcome, and therefore compromise between each parameter which is mutually restricted needs to be made. For another example, if the single-pixel accuracy needs to be improved, and meanwhile, the accuracy needs to be improved by adopting more navigation star adjustment measurements, the field of view, the entrance pupil aperture and the focal length need to be increased when the pixel size of the detector is fixed, the weight volume is increased in a cubic progression, the volume and the weight of the star sensor are inevitably huge, the detector also needs a large area array, and the accuracy and the information processing rate are negatively affected. The indexes are mutually restricted, which brings a series of design problems which are difficult to overcome. If the index is to obtain the full-quality, the ultra-high precision is obtained by the small aperture of the small visual field and the small star number, and simultaneously, the small solar suppression angle is ensured, and a breakthrough must be made in principle.

Although the principle and the design method of the existing star sensor used in the daytime in the land, sea and air field are mature, the star sensor is influenced by the atmospheric radiation background noise, a near infrared (900nm-1700nm) spectrum band is adopted, the detection sensitivity of the star sensor is low, single-star directional navigation is mostly relied on, the directional precision of a single star is difficult to improve due to threshold lag effect, generally, the star sensor is a few angular seconds, and the star sensor must be innovated in principle to obtain the directional precision improvement effect of multiple stars and achieve the precision of 0.1' -magnitude. Most of the existing airborne and missile-borne star sensors are oriented in a single star, mainly because fixed stars which can be detected in an atmospheric background generally need to be more than 3 bright stars, and the number of the bright stars in the celestial sphere is limited. Some airborne star sensors obtain multi-star orientation capability through a scanning method, however, the number is still limited, a multi-star adjustment method cannot be adopted to improve the orientation precision, and the conventional breaking through from a new principle imaging system is needed to obtain the multi-star navigation precision through a single-star navigation star.

The prior transmission type star sensor optical system has the defects that the thermo-optical characteristic of a lens is difficult to eliminate due to the change of a temperature field, the means of thermal compensation through an optical machine structure is limited, and the position drift of an imaging star point can be caused when the temperature field of a working environment changes, so that the pointing drift of an optical axis of the star sensor is caused.

The above problems cause obstacles to further improvement of the star sensor precision, so that the current international star sensor precision is not before the development of a dead stop around 0.1' (1 sigma), and a performance threshold hysteresis effect occurs.

Disclosure of Invention

The technical problem solved by the invention is as follows: the star sensor can realize the spanning of the limit precision from 0.1 '-magnitude to 0.01' -magnitude under the condition of the same size and quality, the subaperture array refers to that a plurality of subapertures with the diameter smaller than the whole aperture are arranged in the whole aperture of an optical system of the star sensor, and the plurality of subapertures with the diameter smaller than the whole aperture are arranged into an array according to the result rule of optical design.

The technical solution of the invention is as follows:

a subaperture array interference star sensor comprises a subaperture array light shield, a subaperture array mask plate, an interference imaging optical system, a thermal measurement and control system, a photoelectric array detector, an image acquisition circuit, an information processing circuit and a star point cluster positioning and star point cluster pattern identification module;

the interference imaging optical system is characterized in that a plurality of sub-apertures with the diameters smaller than the whole aperture are arranged in the whole aperture of the optical system of the star sensor, the plurality of sub-apertures with the diameters smaller than the whole aperture are arranged into an array, and the target is subjected to interference imaging on an imaging surface through the array formed by the plurality of sub-apertures;

the sub-aperture array light shield is composed of a plurality of light shields, the arrangement mode of the light shields is symmetrical about an optical axis, the light shields correspond to the sub-apertures on the interference imaging optical system one by one, and the sub-aperture array light shield is positioned on the sub-apertures of the interference imaging optical system;

the sub-aperture array mask plate is positioned at the entrance pupil of the interference imaging optical system, and is provided with a plurality of openings which correspond to the sub-apertures on the interference imaging optical system one by one;

the thermal measurement and control system is an embedded full-field thermal measurement and control system of the whole instrument based on fiber bragg grating sensing and is used for measuring the whole temperature field of the star sensor;

the photoelectric array detector is used for sensing the imaging of the target, and the side peak of the interference image can still be sensed when the brightness of the target reaches the sensitivity;

the image acquisition circuit and the information processing circuit are used for extracting and matching the star map of the interference imaging and are also used for calculating and outputting the attitude;

the star point cluster positioning and star point cluster image identification module is used for positioning a star point cluster and identifying a star image formed by the star point cluster, the star point cluster is an image formed by an interference imaging optical system on a fixed star, and the image is formed by a main peak and a plurality of side peaks;

the method for determining the sub-aperture on the interference imaging optical system comprises the following steps:

light emitted by a target point close to infinity enters from each hole of the mask plate and is in a state of separating a plurality of imaging light beams, the light is imaged on a focal plane through an interference imaging optical system, interference imaging is carried out on the focal plane to form a star point cluster image spot, the energy and form distribution of the star point cluster image spot is determined by a point expansion function, and the point expansion function is the square of an amplitude function digital-analog of a subaperture array pupil function of the mask plate. The method comprises the steps of taking the specific requirements of the number of side peaks, the energy and the spatial distribution of a star point cluster as constraint conditions, taking the maximum duty ratio of the sum of the sub-aperture areas to the whole aperture area as an objective function, determining the initial size, the number and the spatial distribution of the sub-apertures according to an optical design method, calculating by using optical system design software to obtain the energy and the spatial distribution of the star point cluster, obtaining a design result of the sub-apertures if the requirements are met, and performing iterative calculation if the requirements are not met until the requirements are met.

The requirements according to the energy and spatial distribution of the star point cluster are: the main peak and the side peak of the star point cluster and the minimum distance between the adjacent side peaks are selected according to the following criteria: the minimum distance between the outer edges of 80% of the energy containing energy peaks is not less than 0 pixel, preferably in the range of 1-100 pixels.

The value of n is the sum of all side peaks and main peaks, wherein the energy of the side peaks is not less than 10% of the energy of the main peaks;

the number of side peaks of the star point cluster is more than 2, and the preferred number is 4-100;

the subaperture array interference imaging star sensor adopts an interference imaging optical system and a subaperture array mask plate positioned at an entrance pupil of the system to form a multi-aperture interference imaging system, each subaperture of the subaperture array is provided with a respective light shield, and the subaperture light shields are integrated into a subaperture array light shield; an instrument complete machine embedded full-field thermal measurement system based on fiber bragg grating temperature sensing is adopted, a plurality of grating sensors are engraved on a measuring optical fiber, ring-shaped or linear multipoint sensors are manufactured according to the attachment characteristics of different optical elements and are embedded into optical system parts, and the distributed measurement of the temperature inside an optical system and the complete machine full-field temperature is realized; the method comprises the steps of enabling light beams from fixed stars to enter an interference imaging optical system through all light-transmitting sub-apertures of a multi-aperture array light shield and a sub-aperture array mask plate, and performing interference imaging on a high-sensitivity photoelectric array detector to form a star point cluster formed by a main peak and a plurality of side peaks according to a specific distribution rule.

The star point cluster positioning is a method for carrying out interference imaging on each star target on an image plane into a star point cluster with a plurality of energy peaks according to the regularity of a point spread function of an optical system by using a multi-aperture interference imaging principle and adopting a sub-aperture mask plate and an interference imaging optical system, and improving the positioning precision of a single star on the image plane through multi-point positioning adjustment, wherein the interference imaging optical system has the following characteristics: the entrance pupil is a real pupil, the preferred distance is 0-10 mm in front of the first optical surface of the optical system, and the right side surface of the subaperture mask plate is positioned on the entrance pupil of the interference optical system.

The number requirement of the side peaks of the star point clusters and the criterion of the distance between the peaks are realized by optimizing the diameters of all sub-apertures on a sub-aperture array mask plate and the mutual position relation, according to the multi-aperture interference imaging principle, the formation of the star point clusters corresponds to the point spread function of a sub-aperture array interference imaging optical system one by one, the size and the distribution of the sub-apertures on the sub-aperture mask plate correspond to the point spread function of the optical system one by one, and therefore the star point clusters meeting the above criteria can be realized by selecting the parameters and the layout of the sub-aperture array mask plate.

The interference imaging star sensor comprises a fixed star target, a plurality of fixed star imaging optical systems and a plurality of interference imaging optical systems, wherein the fixed star target is imaged on a focal plane through a sub-aperture array mask plate and the interference imaging optical systems, the image of each fixed star is a star point cluster formed by imaging on the focal plane through multi-beam interference, the star point cluster consists of a central main peak and a plurality of side peaks, the number of the side peaks of the star point cluster, the distribution of the side peaks relative to the main peak, and the energy and dispersion diameter distribution of the main peak and the side peaks depend on the technical and performance parameters of the sub-aperture array mask plate and the interference imaging optical systems;

the method for measuring the attitude by the subaperture array interference star sensor comprises the following steps:

the light beam from a certain target star firstly reaches a sub-aperture array mask plate through a sub-aperture array light shield, is divided into a plurality of sub-aperture light beams by the sub-aperture array, enters a first optical surface of an interference imaging optical system after passing through the sub-aperture array of the sub-aperture array mask plate, and the multi-aperture light beams respectively pass through the interference imaging optical system and then generate interference imaging on a focal plane thereof to form a star point cluster image which is formed by a plurality of points with obvious main peak and side peak separation characteristics and small energy difference, each star target in a visual field of the interference imaging optical system can form a star point cluster with the same point spread function, a star point cluster star image captured by the whole visual field forms a star point cluster star image which is received by a photosensitive surface of a high-sensitivity photoelectric array detector arranged on the image plane and a photoelectric digital image of one target is acquired and stored through an image acquisition circuit and an information processor circuit, and star point cluster positioning and star point cluster map recognition software embedded in the memory is adopted to process the star point cluster star map to obtain attitude measurement information of the star sensor.

The sub-aperture array interference imaging optical system is a complete optical system designed and manufactured by a whole aperture, the entrance pupil of the optical system is formed into a sub-aperture array by arranging a plurality of sub-apertures smaller than the whole aperture according to a set spatial layout, a plurality of sub-apertures are imaged on a target respectively through the complete optical system, interference occurs on an image plane, and a star point cluster formed by a main peak and a plurality of side peaks is formed.

The size, shape and position of all sub apertures contained in the sub aperture array are obtained by optimizing the target of the optimal star point cluster positioning precision and the maximum sub aperture array filling factor and by taking the specific requirements of the side peak number, energy and space distribution of the star point cluster and the performance parameters of the interference imaging optical system as constraint conditions. The optimization process is different from the design optimization technology of the traditional synthetic aperture telescope. The optimization of the design of the synthetic aperture telescope takes MTF with optimal full space frequency coverage and minimum filling factor as the target to optimize the layout of the sub-pore array. The synthetic aperture telescope does not adopt the concept of a star point cluster, does not find the favorable characteristics of the synthetic aperture telescope on positioning precision, and only pursues the concentration and sharpness of a point expansion function and the improvement of imaging MTF. The distance between the main peak and the side peak of the point spread function is required to be as small as possible, and is generally smaller than 1 pixel, even overlapped. The invention provides a concept of a star point cluster, improves the star point positioning precision by utilizing the star point cluster, and provides specific requirements of the star point cluster such as shape, energy distribution, energy peak number and the like. Compared with the design of a synthetic aperture telescope, the design method does not have the design target of widening the subaperture base line as much as possible, does not meet the requirements of MTF and other imaging quality requirements, and does not have the design requirement of pursuing the minimum filling factor on the premise of ensuring the imaging quality. On the contrary, the invention is used for a small-entrance pupil optical system, does not have the requirement of widening the subaperture base line as much as possible, pursues the filling factor as much as possible, and puts the requirement on the degree of dispersion of a star point cluster. The invention is different from the prior star sensor technology in that the formed star point cluster star image replaces the star point star image in the prior art, and is completely different from the prior art in the information acquisition and information processing method. The invention has the greatest advantage that the star point clusters are utilized for packagingCompared with the prior art that a single star point is positioned on the image surface, the precision of the positioning of the plurality of star points on the image surface can be greatly improved. The sampling sample number can be increased by utilizing the star point cluster, and according to the precision theory, the positioning precision of the star point cluster is improved to be higher than that of a single star point according to the result

The multiple n is the number of the star points contained in the star point cluster, so that the extraction precision of a single star point, which is a main influence factor of the precision of the star sensor, can be greatly improved in principle, and the highest precision level of the star sensor in the prior art is improved from 0.1 'to the 0.01' order of the invention by utilizing the multiple star adjustment, so that the precision of the star sensor is improved by one order of magnitude. At the same time, the precision of acquisition is improved

Under the multiple advantage, the instrument also provides a novel light shield structure such as a subaperture array light shield (1), and due to the thinned aperture, the solar stray light can reach the outlet after being reflected for multiple times, so that the stray light eliminating capability is greatly improved, the length of the light shield can be shortened under the same stray light eliminating capability, or the stray light eliminating capability is greatly improved under the condition of keeping the length of the light shield.

The sub-aperture array light shield is an array composed of a plurality of sub-aperture light shields, the number of the sub-aperture light shields is equivalent to the number of sub-apertures, each sub-aperture light shield in the array has a central symmetry axis, the central symmetry axes are parallel to the optical axis of the interference imaging optical system, the incident end face and the emergent end face of each sub-aperture target light ray are generally parallel and can not be parallel when the sun or other parasitic light in a specific direction is intentionally inhibited, the emergent end face of each sub-aperture light shield is positioned on the entrance pupil plane of the interference imaging optical system, a set small distance is allowed to be arranged between the front and the back of the entrance pupil plane, and the size of the distance depends on the allowable loss amount of incident energy of the system and the limitation of the external dimensions of the sub-aperture light shield. The inside of the sub-aperture light shield is completely blackened by using dull black paint and is provided with a light ring, the inner diameters of all light blocking rings are ensured not to block a view field, the lower part of an installation error is reserved for blocking the view field, the outer diameter of each light blocking ring depends on the width of the light blocking ring, and the width of the light blocking ring depends on the stray light eliminating capacity and the design scheme. The light blocking ring can be fixed in the outer wall cylinder of the sub-aperture light shield through a connecting piece and can also be directly and integrally processed by a block of material through machining. The sub-aperture array lens hood can be designed and manufactured into a whole, and can also be divided into a plurality of sections which are fixedly connected by adopting connecting pieces.

The sub-aperture array mask plate is positioned at the entrance pupil position of the interference imaging optical system and can also be regarded as a part of the optical system. The position of the optical system is strictly positioned at the entrance pupil of the optical system, and a set error can be allowed, wherein the error is within the range of process guarantee. A plurality of holes are formed in the sub-hole array mask plate and are arranged in a certain array, and the size and the position of the holes are obtained by adopting an optimal star point cluster energy state distribution optimization method. This optimization method is described as follows: light emitted from a target point near infinity. The method comprises the steps of entering holes of a sub-hole array mask plate in a state of separating a plurality of imaging light beams, imaging on a focal plane through an interference imaging optical system, and performing interference imaging on the focal plane to form an image spot, wherein the energy and form distribution of the image spot are determined by a point spread function, the point spread function is determined by the size and the spatial layout of sub-holes of the sub-hole array mask plate, according to the Fourier optical theory, the sub-hole array of the sub-hole array mask plate is a pupil function, the Fourier transform of the pupil function is an amplitude function, and the square of an amplitude digital-analog function is a point spread function. The point expansion function form of the interference imaging of the multiple sub-aperture light beams is composed of multiple peaks, a main peak is arranged in the center, a plurality of side peaks are arranged around the main peak, the energy of the main peak is different from that of the side peaks, the energy of the main peak is generally larger, the energy of the side peaks is generally smaller, the energy state distribution of the point expansion function of the sub-aperture array interference optical system can be changed by optimizing the change of a pupil function, namely the distribution of the multi-peak energy state in an image surface space, and the multi-peak point expansion function is called as a star point cluster. From the viewpoint of the star point positioning accuracy of the star sensor, the determination principle of the optimal star point cluster is as follows: the smaller the energy difference between the main peak and the side peak is, the better, the more the side peaks are, the better each energy peak is, and the more each energy peak is independent, the specific requirement is as described above, and this optimization principle is not adopted by the existing interference imaging technology, and the optimal positioning precision of the star point cluster is obtained at the expense of MTF and imaging resolution. The optimal star point cluster can be obtained by changing the subaperture size and the position spatial layout of the subaperture array mask plate, namely changing the pupil function of the interference optical system. The optimal star point cluster is obtained, and the size, the shape and the position of the opening of the sub-pore array mask plate are also obtained.

The interference imaging optical system is used for focusing and imaging the multi-aperture imaging light beams divided by the sub-aperture array mask plate, the multi-imaging light beam interference occurs on an image surface, and the sub-aperture array mask plate is arranged near an entrance pupil. Generally, a reflective or refraction-reflection optical system is adopted for the design indexes of a long focal length (about more than 300mm for the star sensor) and a small visual field (no more than 5 degrees of circular visual field for the star sensor), the system is a complete system, and a primary mirror and a secondary mirror are complete without division of the primary mirror and the secondary mirror. For design indexes of medium and short focal length (less than 300mm for the star sensor) and above a medium field of view (more than 5-degree circular field of view for the star sensor), besides a catadioptric system and a reflecting system, more refractive optical systems are adopted, the system is still a complete system, and an entrance pupil covers the maximum envelope of the sub-aperture array;

the embedded full-field thermal measurement and control system based on the fiber bragg grating sensing is used for measuring the overall temperature field inside and outside the instrument, a plurality of multi-point fiber bragg grating temperature sensors are adopted, a plurality of sensitive measurement areas with grating structures are manufactured on each measuring fiber, the sensors are embedded into grooves dug in advance at the edges of an optical reflector substrate and an optical lens and fixed, simultaneously penetrate through the instrument structure and are fixed structurally, the fiber multi-point temperature sensors can penetrate into all layers of the optical-mechanical-electrical machine of the whole instrument to obtain a global temperature field measurement three-dimensional measurement point network, so that a complete machine temperature field model can be established relatively accurately, and the efficiency can be improved and the resources of the fiber sensor system can be saved by using one multi-point fiber. The number determination of the temperature measuring points and the position selection principle of each temperature measuring point are as follows: the modeling precision of the global temperature field is ensured to be better than 0.5 ℃.

The high-sensitivity photoelectric array detector is realized by two modes: one is a single high sensitivity visible or near infrared photodetector such as an EMCCD, sCMOS device, or InGaAs. And the other is to adopt an image intensifier and a high-sensitivity detector to combine to form an enhanced high-sensitivity photoelectric detector, such as IsCMOS combining the image intensifier and sCMOS, IInGaAs combining a near-infrared image intensifier and InGaAs and the like. The first approach is used for cases where the detector noise is very low (several electrons), the detection sensitivity is very high (several photons) and the quantum efficiency is above 50%. The second approach is used in situations where there is a higher sensitivity requirement than the first.

The image acquisition circuit and the information processor circuit are used for an instrument electronic system consisting of a detector image acquisition circuit with the image acquisition capacity of more than 50 Hz-100 Hz and an information processor circuit. In order to meet the complete capture of a star map of a star point cluster, realize clear sampling of a main peak and a side peak of the star point cluster and cover all specified star equal ranges, a high-dynamic high-sensitivity photoelectric array detector is required to be adopted. Meanwhile, in order to improve the star point positioning precision, the invention provides a temporal filtering and star point cluster multi-peak positioning spatial filtering dual-noise reduction method for multi-frame image regression positioning, which comprises the following steps: the three-axis instantaneous angular rate of three-axis motion of the star sensor is indicated by adopting a three-axis microminiature gyroscope, the moving amount of star points of two adjacent frames of images on an image surface can be calculated according to the three-axis instantaneous angular rate and a focal length value, the moved images can be regressed onto an initial image, and the multiframe image regression time filtering noise reduction positioning is carried out. Each frame of image is positioned by spatial filtering of a multi-peak star point cluster, precision improvement rates of the multi-peak star point cluster and the multi-peak star point cluster have multiplication characteristics, and the star point positioning method of the star sensor is greatly improved. This is achieved on the premise that an information processor with a high data update rate, for example, a high data update rate of not less than 50Hz to 100Hz, is used.

The star point cluster positioning and star point cluster image identification software is used for identifying and positioning star point clusters of star point cluster star image images formed by an interference imaging optical system on a fixed star target, and further identifying and positioning star point images, and the algorithms in the prior art are designed for star point star images, so that the method is not suitable for the method. In the prior art, a common optical system is adopted, and an obtained star map is a star point star map, namely, one star corresponds to one star point image spot. The size of n varies with the pupil function constructed by the sub-aperture mask plate, n can obtain a specific number under different pupil functions, and n can obtain a positive integer set theoretically along with the variation of the pupil function, but in practical application, the increase of n brings energy reduction of a single star point, so the number of n is selected in a compromise way, for example, n can be selected to be 5, 6, 7, … …, and 100.

The scheme of the invention is not only suitable for improving the precision of the star sensor, but also has wide application, and is suitable for imaging and positioning of all point targets or close point targets so as to improve the positioning precision. Such as sun sensors, rare navigation star sensors, laser communication aiming or alignment imaging, target monitoring, tracking and positioning, target dynamic and static positioning of dotted images and other application occasions. The imaging positioning method adopting the interference imaging star point cluster positioning belongs to the protection scope of the patent.

Compared with the prior art, the invention has the beneficial effects that:

(1) the invention uses multi-aperture interference imaging to obtain star point clusters with considerable expansion, creates the application condition of a multi-point multiplexing adjustment method, and improves the positioning precision of the target star.

(2) The sub-aperture array interference star sensor provided by the invention adopts a new imaging system, so that an image formed by a fixed star is converted into a star point cluster comprising a plurality of star points, the number of sampling samples for star point positioning is increased, and random errors can be reduced to be single star points in the prior art according to the error statistical principle of the precision theory

And the maximum precision level of the star sensor in the prior art can be improved from 0.1 to more than 0.01, and the performance of the star sensor is greatly improved. Slave bookThe problem of insufficient single-star positioning precision in the prior art is solved essentially. Meanwhile, due to the design of the sub-aperture array, the light shield of the instrument is changed into a short and exquisite sub-aperture array light shield, so that the solar stray light suppression angle is reduced by about 10 degrees compared with the prior art, and the installation possibility, convenience and application universality of the instrument on the spacecraft are greatly increased.

(3) In the existing star sensor design theory, the formula for calculating the pointing accuracy of an optical axis is as follows:

ξ_spositioning error of a single star, N_starThe number of stars participating in the accuracy calculation.

The method is characterized in that a direction vector of a known fixed star is measured through an imaging system, namely the direction vector of an optical axis of an instrument is determined, the measurement of each fixed star is used as an independent random event by using the precision theory, N observation vectors can be obtained if N fixed stars are shot by the imaging system to generate N star point images, the N observation vectors can reversely calculate the direction vector of the optical axis, the N independent observation random events are equivalent to N independent observation measurement random events, the observation error is normally distributed every time, and the N observation mean square error is observed once

Multiple, that means improved accuracy by a single star

And (4) doubling. Due to the influence of non-random errors, the navigation satellite number in the prior art reaches saturation when the navigation satellite number is increased to a certain degree, and practical experience shows that the saturation phenomenon is generated when N is 25, so that the optical axis pointing accuracy is 0.02 pixel if the single satellite positioning accuracy is 0.1 pixel. This is the highest level of accuracy that can be achieved with prior art star sensors. If the pointing accuracy of the optical axis is continuously improved, the single-star positioning accuracy needs to be improved. The calculation of the single-star positioning precision generally adopts two types of methods, one is a centroid method and an improved algorithm thereof; one is energy division according to star pointThe cloth and morphology were fitted to the position of the distribution center. Both methods are mature at present and can reach the maximum of 0.01 pixel magnitude theoretically, but in practice, only reach the 0.1 pixel magnitude level due to the non-uniformity of star points and the influence of high-frequency and low-frequency errors of a detector. The methods for improving the precision that can be adopted by the prior art have reached a limit level, the highest precision obtained being generally of the order of 0.1 ". The invention breaks through the limiting factor of the precision level, provides a new sub-aperture array interference imaging system, converts the fixed star imaging of the prior art into single star point imaging into star point clusters, namely converts the positioning of one star point into the positioning of a plurality of star points, greatly eliminates the random error of the positioning,

therefore, the single-star positioning obtains the multi-star positioning precision, and the new calculation method has the following formula:

(4) the optical axis positioning precision of the invention is improved to the state of the art

And (4) doubling. The n can be optimally designed through the interference imaging of the sub-aperture array, various different n values can be obtained through the optimization of the sub-aperture array, and a large number of values from 1 to infinity can be obtained theoretically, but in practice, the energy of a main peak and each side peak of a star point cluster can be greatly reduced due to the fact that the n value is too high, and therefore the n value actually adopted for the star sensor is generally limited to be not more than 100. Where k is the star point cluster geometry influencing factor,

related to the distance between the main peak and the side peak. Therefore, the invention can improve the single-star positioning precision in the prior art

And (4) doubling. In essence, the star point cluster multi-point adjustment constructed by the method can be used for improving the single-star positioning accuracyThe method is a spatial filtering and noise reduction method which divides a single star point into multiple points in an image space, is equivalent to star point multiplexing adjustment, and does not adopt a spatial filtering and noise reduction method which positions the multiple point adjustment by a star point cluster in a conventional multi-aperture telescope system.

(5) The invention provides an image-enhanced star map acquisition scheme with ultrahigh detection sensitivity, which aims at the problem that navigation star image trace aliasing caused by main lobe side lobe energy difference and energy difference of bright and weak stars and the like of a sub-aperture array interference imaging star point cluster is difficult to extract by using the existing algorithm, utilizes the combination of rapid coarse positioning of a receptive field neural network and fine positioning of a symmetric space transformation network to break through a new star point cluster extraction positioning method, the method for inquiring the positions of the star point clusters of different stars and the like in a layering mode through a receptive field neural network training star point cluster space energy form distribution model achieves coarse positioning and aliasing image identification and confirmation of the star point clusters of each energy level, accurately positions the star point clusters through a symmetrical space transformation network, calculates the coordinate positions of the star point clusters through a star point cluster space filtering and multi-frame time filtering multiplicative double-filtering noise reduction method, and provides a unique and accurate navigation star map for star map matching and identification. The invention also adopts a method for improving the precision of removing random noise by multi-frame image regression resampling filtering guided by the angular rate of a triaxial MEMS gyroscope, and the method essentially utilizes the noise adjustment action of a single star point of fixed star imaging in a time sequence, reduces the positioning error by a multi-frame image regression overlapping filtering method, and becomes the time filtering noise reduction. The method is adopted on the basis of a star point cluster multi-point filtering noise reduction method, so that the method has the function of multiplicatively improving the precision. The method is characterized in that multi-frame image temporal filtering denoising is carried out on the basis of star point cluster spatial filtering denoising, and the method is called as a spatial and temporal multiplicative filtering double denoising method.

(6) The invention breaks through the common conjugate imaging principle mode that the fixed star and the star image point of the existing starlight tracker are in one-to-one correspondence based on a geometric optical imaging system, provides a new system star map acquisition and positioning identification mode that the fixed star and the star point cluster of multi-aperture interference imaging are in one-to-many correspondence, establishes an optimal configuration evaluation and optimization method of the star point cluster by extending a multi-peak point expansion function into a new principle of the star point cluster through heterogeneous optimization of a multi-aperture interference imaging structure, and solves the problem of performance threshold hysteresis effect caused by inherent random errors of the existing starlight tracker.

(7) The invention breaks the understanding of the existing star light tracker technology on the high-frequency error and low-frequency error inherent, provides a mechanism for eliminating high-frequency and low-frequency error sources by introducing a star point cluster, obtains the optimal lobe number and energy state distribution imaging mode of the star point cluster, and finds out an energy state distribution model with the optimal extraction precision of the star point cluster position through heterogeneous optimization of a pupil function and a simulation iteration verification method of the high-frequency and low-frequency errors of the star light tracker, thereby achieving the effect of improving the precision in a cross-magnitude manner and obtaining the new principle feasibility of the sub-aperture array star light tracker.

(8) The invention provides a multidisciplinary optimization design and evaluation method of a novel system instrument by taking energy state distribution of an optimal precision star point cluster and a maximum filling factor of a sub-aperture array as a target function aiming at the problem that performance threshold hysteresis effect caused by an instrument optimization design and evaluation method based on a common conjugate imaging system in the prior art can not break through, solves the design problems of optimal distribution of a pupil function, shortened size of a light shield, reduced solar suppression angle, improved star point positioning precision, identification and matching of a star point cluster star map, high dynamic detection and circuit noise suppression, temperature induced optical axis drift, land, sea, air and space environment adaptability and the like, improves the technical characteristics, universality, robustness and applicability of the instrument, the optical axis pointing precision and the solar suppression angle of 20 degrees can reach 0.01', and a new method is provided for improving the precision and other performances of an interference imaging star-light tracker and even a general point category identification tracking scientific instrument.

(9) The invention provides a new system of multi-aperture interference imaging of a common primary mirror and a secondary mirror of a sub-aperture array lens hood, which aims at solving the problem that the inclination and the piston error of the segmentation, registration and adjustment of a primary mirror of the imaging structure of the existing large-size telescope multi-aperture interference imaging system are difficult to eliminate, creates a multi-aperture interference imaging mode combining a sub-aperture mask plate and a complete primary mirror, the new method for optimizing the pupil function by combining the entrance pupil aperture mask plate and the sub-aperture light shield solves the two kinds of error problems of the segmentation and registration piston and the inclination of the main mirror in the prior multi-aperture synthesis technology, the registration error between the sub-apertures of the Fizeau multi-aperture interference star-light tracker is zero, the precedent of the application of multi-aperture synthetic interference imaging in a small-size optical system of a tracking instrument is created, the length of the light shield is shortened to be within 100mm through the small size of the sub-aperture, and the possibility of installation of the ultra-high precision star light tracker in limited space environments such as an airborne environment is expanded.

(10) The invention provides an embedded global temperature field measurement and control compensation method for fusing a fiber grating temperature sensor and an optical part, aiming at the problem that the thermotropic axis drift of a starlight tracker in the prior art cannot be further eliminated in the order of ten seconds, solves the problem that the thermotropic axis drift cannot be measured and controlled and compensated in real time due to the fact that no means are used for measuring the temperature field inside the optical system part in the prior art, provides a thermotropic drift compensation model, enables the compensated optical axis drift angle to be reduced to the order of 0.01', provides guarantee for realizing long-term gazing target observation and tracking aiming scientific tasks, and enables the position precision of deep space navigation and earth orbit satellite autonomous navigation to be increased to within 10m from the order of 100 m.

(11) The invention can be applied to other occasions of small-view-angle target imaging positioning within 1 degree.

Drawings

FIG. 1 is a schematic diagram of the construction of a sub-aperture array interference star sensor of the present invention;

FIG. 2 is a schematic view of sub-aperture forming according to the present invention;

FIG. 3 is a schematic view of a subaperture array of the present invention;

FIG. 4 is a diagram of a one-dimensional spreading function;

FIG. 5 is a two-point spread function.

Detailed Description

As shown in fig. 1-2, the invention provides a subaperture array interference star sensor, which comprises a subaperture array light shield 1, a subaperture array mask plate 2, an interference imaging optical system 3, an instrument complete machine embedded full-field thermal measurement and control system 4 based on fiber bragg grating sensing, a high-sensitivity photoelectric array detector 5, a detector photosensitive surface 6, an image acquisition circuit and information processor circuit 7, star point cluster positioning and star point cluster diagram identification software 8, a mechanical installation interface 9, a power supply interface 10, a communication interface 11 and a detection interface 12. A light beam from a certain target star firstly passes through a subaperture array light shield 1 to reach a subaperture array mask plate 2, is divided into a plurality of subaperture light beams 14 by a subaperture array 13, enters a first optical surface of an interference imaging optical system 3 after passing through the subaperture array of the subaperture array mask plate 2, and after passing through the interference imaging optical system 3, the multi-aperture light beams respectively generate interference imaging on a focal plane thereof to form a star point cluster image which is formed by a plurality of points with obvious main peak and side peak separation characteristics and small energy difference, each star target in a field of view of the interference imaging optical system 3 forms a star point cluster with the same point spread function, a star point cluster star image captured in the whole field of view forms a star point cluster star map which is received by a photosensitive surface 6 of a high-sensitivity photoelectric array detector 5 arranged on the image plane, and a photoelectric digital image of the target is obtained and stored by an image acquisition circuit and an information processor circuit 7, and star point cluster positioning and star point cluster map recognition software 8 embedded in a memory 7 is adopted to process the star point cluster star map to obtain attitude measurement information of the star sensor.

The invention is further explained below with reference to the drawings and the examples.

Examples

The light shields are manufactured according to the sub-aperture array position and the opening size of a sub-aperture mask plate, each sub-aperture full-field incident light beam is guaranteed to have no vignetting or a small amount of vignetting (for example, less than 30%), the height of an inner diameter baffle of each sub-light shield is 0.5mm lower than the maximum field envelope so as to adapt to the installation tolerance of the light shields, the inlet size of each sub-light shield is determined according to the requirements of a field angle and the tolerance, and the length of each sub-light shield is designed according to the principle of being shortest on the premise of guaranteeing the stray light elimination performance. The interference imaging optical system 3 adopts a catadioptric optical system, and the design indexes are as follows: the focal length is 300mm, the entrance pupil is positioned on the light-emitting surface of the sub-aperture array mask plate, the design aperture is 100mm, the field angle is 2.2 degrees of conical field, and the central blocking is not more than a disc with the diameter of 30 mm. The imaging quality is designed to approach the diffraction limit level. The subaperture array mask plate is a flat plate part, the shape can be circular along with the design, also can be other shapes, the external diameter size is the same as the designed entrance pupil diameter, is 100mm, a plurality of holes are dug on the mask plate, in this case, the circular holes with different sizes are distributed in an internal and external concentric circular array, 8 circular holes with phi 10mm are arranged on the first ring, 8 circular holes with phi 6mm are arranged on the second ring, and the subaperture array mask plate is the entrance pupil of the subaperture array interference optical system 3.

The spread function of the interference optical system for star imaging can be designed by adopting optical design software, in the embodiment, the ZEMAX software is adopted for design, and the obtained one-dimensional and two-site spread functions are shown in fig. 4 and 5.

As can be seen from fig. 4, at least 7 extractable peaks can be obtained in one dimension, including 1 main peak and 6 side peaks. It can be seen from fig. 5 that the interference optical system with the sub-aperture array layout according to fig. 3 can obtain a one-dimensional distribution in 16 directions, so that at least 112 side peaks can be obtained, and the accuracy of the present invention can be improved by 10 times compared with the prior art without increasing the volume weight according to the calculation of the formula of the present invention.

The refraction and reflection type optical system is adopted in the scheme, other types of optical systems can be adopted, such as reflection type and transmission type, the required optimal star point cluster can be obtained through the aperture optimization of the sub-aperture array mask plate, and the precision is realized

And 5, double promotion.

The implementation of the embedded global temperature field measurement and control compensation method with the fusion of the fiber grating temperature sensor and the optical part mainly solves the problem that the thermal optical axis drift cannot be measured and controlled and compensated in real time due to the internal temperature field of the optical system part, and the installation mode of the fiber sensor of the reflector optical part is that a groove is arranged in a downward mode.

The implementation scheme of the subaperture array layout optimization method taking the optimal star point cluster as the target mainly obtains different star point cluster energy and form distributions through the subaperture array layout change of a subaperture array mask plate, and calculates the positioning precision through the positioning algorithm of the star point cluster, so that the layout reaching the expected precision is the design result.

In the past, a common geometric optical conjugate single-aperture imaging system is adopted in an asteroid direction finder, target fixed star imaging is a star point image, the improvement potential of star point positioning accuracy is developed almost all the time, the consensus of the industry is formed, the accuracy threshold hysteresis effect cannot be broken through, and the star point extraction accuracy generally stays at the 0.1 pixel level and cannot be broken through. The project has been suggested by scholars to adopt high-speed photography multiple image superposition, and to use temporal random error filtering to eliminate uniform random noise, which can reach 0.01 pixel level, but needs to waste processing time and image resources. The project adopts a novel sub-aperture array interference imaging system, extends single star point space into a multi-peak star point cluster through sub-aperture array interference imaging system design and optimal star point cluster pupil function optimization, removes random errors by applying spatial filtering, and can obtain star point positioning accuracy better than 0.02 pixel by only one image. And then, overlapping a plurality of continuous graphs with a data updating rate of 100Hz, applying temporal filtering to eliminate uniform random noise, improving the precision by 10 times, achieving the star point positioning precision superior to 0.002 pixels, and realizing the single-star positioning precision of 0.001' magnitude under the volume weight and the focal length in the prior art.

The high-sensitivity photo-array detector 5 of the present case is implemented by two types: the high-sensitivity photoelectric detector EMCCD is aimed at a visible light sidereal target, and the high-sensitivity photoelectric detector InGaAs is aimed at a sidereal target in a near-infrared 900nm-1700nm spectrum band.

The image acquisition circuit and the information processor circuit 7 are used for an instrument electronic system consisting of a detector image acquisition circuit with the image acquisition capacity of more than 100Hz and an information processor circuit.

Claims

1. A subaperture array interference star sensor is characterized in that:

the optical system of the star sensor is an interference imaging optical system, the interference imaging optical system is characterized in that a plurality of sub-apertures with the diameter smaller than the whole aperture are arranged in the whole aperture of an entrance pupil of the optical system of the star sensor, the plurality of sub-apertures are arranged into an array, light emitted by a target forms an array clear aperture through the plurality of sub-apertures, and then the interference imaging optical system performs interference imaging on a fixed star and other point targets on an imaging surface to obtain star point cluster images;

each sub-aperture of the interference imaging optical system of the star sensor is provided with a light shield;

a mask plate is arranged at the entrance pupil of an interference imaging optical system of the star sensor, a plurality of openings are formed in the mask plate, and the openings correspond to the sub-apertures in the interference imaging optical system one by one.

2. The subaperture array interferometric star sensor of claim 1, wherein: the side peak number, energy and spatial distribution of the star point cluster generated by interference imaging meet the following requirements:

the percentage of single side peak energy in the main peak energy is R, the number of the side peaks is S, the distance of an energy centroid between two adjacent side peaks or between two adjacent main peaks and the side peaks is L, the minimum distance of the outer edge of 80% of energy between two adjacent side peaks or between two adjacent main peaks and the side peaks is L ', an independence factor between the peaks is T-L'/L, T is more than or equal to 0 and less than or equal to 1, and the positioning accuracy of the star point cluster is A, then the evaluation factor is:

by changing the aperture size and position spatial layout of the mask plate, namely changing the pupil function of the interference optical system, the optimal star point cluster can be obtained, the optimal star point cluster is obtained, the size, the shape and the position of an opening of the mask plate are also obtained, and the value taking method of the star point number n contained in the star point cluster is as follows: the energy of the main peak is not more than 10 percent and the number of all side peaks is increased by one, the number of the side peaks of the star point cluster is not less than 2, and the minimum distance between the main peak and the side peaks of the star point cluster and the adjacent side peaks is selected according to the following criteria: the minimum distance between the outer edges containing 80% of the energy peak is not less than 0.

3. The subaperture array interferometric star sensor of claim 1, wherein: the star sensor also comprises a thermal measurement and control system, wherein the thermal measurement and control system is an embedded full-field thermal measurement and control system of the whole instrument based on fiber bragg grating sensing and is used for measuring the temperature field of the whole instrument of the star sensor;

the star sensor also comprises a photoelectric array detector, wherein the photoelectric array detector is used for sensing the imaging of a target, and the side peak of an interference image formed when the brightness of the target reaches the sensitivity can still be sensed;

the star sensor also comprises an image acquisition circuit and an information processing circuit, wherein the image acquisition circuit and the information processing circuit are used for extracting and matching the interference imaged star map and are also used for calculating and outputting the attitude;

the star sensor also comprises a star point cluster positioning and star point cluster pattern recognition module, wherein the star point cluster positioning and star point cluster pattern recognition module is used for positioning the star point clusters and recognizing star patterns formed by the star point clusters, the star point clusters are images formed by an interference imaging optical system on fixed stars, and the images are formed by a main peak and a plurality of side peaks.

4. The subaperture array interferometric star sensor of claim 1, wherein:

light emitted by a target point close to infinity enters from each hole of a mask plate and is in a state of separating a plurality of imaging light beams, the light is imaged on a focal plane through an interference imaging optical system, the interference imaging is carried out on the focal plane to form a star point cluster image spot, the energy and form distribution of the star point cluster image spot are determined by a point spread function, the point spread function is the square of an amplitude function digital-analog of a subaperture array pupil function of the mask plate, the requirements of the side peak number, the energy and the space distribution of the star point cluster are taken as constraint conditions, the maximum filling factor of the total subaperture area to the whole aperture area is taken as a target function, the initial size, the number and the space distribution of subapertures are determined according to an optical design method, the energy and the space distribution of the star point cluster are calculated by using optical system design software, if the requirements are met, the design result of the subaperture is obtained, if the requirements are not, until the requirements are met.

5. The subaperture array interferometric star sensor of claim 1, wherein: each sub-aperture is provided with a light shield, the optical axis of each light shield is parallel to the optical axis of the optical system, the interior of each light shield is blackened by using matt black paint and is provided with a light blocking ring, and the inner diameter of each light blocking ring is ensured not to block a view field and not to block the view field under the condition of remaining installation errors;

the light blocking ring is fixed on the inner side of the outer wall cylinder of the light shield through a connecting piece or is directly and integrally processed by a block material through mechanical processing.

6. The subaperture array interferometric star sensor of any of claims 2-5, wherein:

the image acquisition circuit and the information processor circuit are an instrument electronic system consisting of the detector image acquisition circuit and the information processor circuit which are used for the image acquisition capacity with high data update rate such as more than 100Hz, the circuit adopts a three-axis microminiature gyro to indicate the three-axis motion instantaneous angular rate of the star sensor, calculates the moving amount of star points of two adjacent frames of images on the image surface according to the three-axis instantaneous angular rate and the focal length value, returns the moved images to the initial image, performs the time filtering noise reduction positioning of multi-frame image regression, and adopts the space filtering positioning of multi-peak star point clusters for each frame of image.

7. A method for attitude measurement based on the subaperture array interferometric star sensor of any of claims 1-6, comprising the steps of:

the light beam from a certain target star reaches a sub-aperture array mask plate through a sub-aperture array light shield, is divided into a plurality of sub-aperture light beams and enters a first optical surface of an interference imaging optical system, the multi-aperture light beams respectively pass through the interference imaging optical system and then generate interference imaging on a focal plane to form a star point cluster image with a main peak and a side peak, each star target in a field of view of the interference imaging optical system forms a star point cluster with the same point spread function, a star point cluster star image is formed by the star image captured by the whole field of view, the star point cluster star image is received by a photosensitive surface of a photoelectric array detector arranged on an image plane, a photoelectric digital image of the target is obtained and stored through an image acquisition circuit and an information processor circuit, and star point cluster positioning and star point cluster image recognition software is adopted to carry out star point cluster star image processing to obtain attitude measurement information of the star sensor, and obtaining the three-axis attitude angular rate information by time differential filtering of the attitude information.

8. Use of a subaperture array interferometric star sensor according to any of claims 1-6, wherein: the method is suitable for observing targets with opening angles not larger than 2 degrees and imaging as point-like images, and is applied to the orientation of a satellite to a natural celestial body, the orientation of a satellite to an artificial target, the orientation of ground equipment to a space base and a space base target, the orientation of ground imaging equipment to a ground target, and the orientation of space base and space base detection equipment to ground and ocean targets.