CN108680165B

CN108680165B - Target aircraft attitude determination method and device based on optical image

Info

Publication number: CN108680165B
Application number: CN201810418096.1A
Authority: CN
Inventors: 韩意; 陈明; 李剑; 张宇; 谢剑锋; 戴堃; 段成林; 孔静; 欧阳琦; 熊飞
Original assignee: Unit 63920 Of Pla
Current assignee: Unit 63920 Of Pla
Priority date: 2018-05-04
Filing date: 2018-05-04
Publication date: 2020-11-27
Anticipated expiration: 2038-05-04
Also published as: CN108680165A

Abstract

The invention discloses a method and a device for determining the attitude of a target aircraft based on an optical image. The method comprises the following steps: acquiring a plurality of simulated optical images and a target actual measurement optical image of a target aircraft at a target moment; determining the simulated optical image with the maximum similarity with the target actual measurement optical image in the plurality of simulated optical images as a target simulated image; and determining first attitude information of the target aircraft in the target simulation image as second attitude information of the target aircraft at the target moment, wherein the first attitude information is used for indicating the attitude displayed by the target aircraft in the target simulation image, and the second attitude information is used for indicating the actual measurement attitude of the target aircraft at the target moment. According to the invention, the effect of estimating the attitude of the target aircraft by an optical external measurement means in the actual space flight test task is achieved, and the attitude measurement requirement of the actual space flight task is met.

Description

Target aircraft attitude determination method and device based on optical image

Technical Field

The invention relates to the field of aircrafts, in particular to a method and a device for determining the attitude of a target aircraft based on an optical image.

Background

During the in-orbit flight of the target aircrafts such as the Tiangong I and the Tiangong II, the ground observation station can track and image the target aircrafts by means of optical external equipment such as a foundation optical telescope. Under the condition that main structures such as a solar array, a resource cabin/an experimental cabin body and the like of a target aircraft on an optical image can be distinguished, the flight attitude of the target aircraft can be estimated and judged based on the optical image, and the on-orbit running condition of the target aircraft can be mastered.

The existing method for estimating the attitude of the aircraft generally comprises two methods, one method is that the attitude is calculated directly based on an actual measurement optical image, but effective characteristic points cannot be extracted under the conditions of fuzzy actual measurement images and low resolution, so the accuracy of estimating the attitude of the aircraft is poor; the other method is a posture estimation method based on three-dimensional model retrieval, which is used for searching the three-dimensional model posture most matched with the characteristic value of the measured image from a database, but the model database is large and complex, the workload is large, and the efficiency of estimating the posture of the aircraft is low.

In addition, the space target attitude estimation method based on the single-station foundation telescope utilizes a development tool Vega Prime to carry out real-time simulation, generates a simulated optical image for the target of a known three-dimensional model in real time, and carries out optimal matching search of the correlation value. However, the method does not consider the geographic position and visual axis pointing of the ground-based telescope and the real-time relative geometric relationship between the target and the telescope when carrying out simulation, so that the simulated optical image does not simulate the target on-orbit flight image shot by the ground-based telescope. In addition, the observation image to be estimated and the reference image are generated by adopting a simulation method, the target contour and the edge in the observation image are clear, the parts are obviously distinguished, and the normalized correlation measurement indexes of the observation image and the reference image and the calculation method are not completely suitable for the optical image of the foundation real shooting.

Aiming at the problem that the attitude of an aircraft is difficult to estimate by an optical external measurement method in an actual space flight test task in the prior art, an effective solution is not provided at present.

Disclosure of Invention

The invention mainly aims to provide a method and a device for determining the attitude of a target aircraft based on an optical image, so as to at least solve the technical problem that the attitude of the aircraft is difficult to estimate by an optical external measurement means in the actual space flight test task.

To achieve the above object, according to one aspect of the present invention, there is provided a target aircraft attitude determination method based on an optical image. The method comprises the following steps: acquiring a plurality of simulated optical images and a target actual measurement optical image of a target aircraft at a target moment; determining the simulated optical image with the maximum similarity with the target actual measurement optical image in the plurality of simulated optical images as a target simulated image; and determining first attitude information of the target aircraft in the target simulation image as second attitude information of the target aircraft at the target moment, wherein the first attitude information is used for indicating the attitude displayed by the target aircraft in the target simulation image, and the second attitude information is used for indicating the actual measurement attitude of the target aircraft at the target moment.

Optionally, acquiring the plurality of simulated optical images of the target aircraft at the target time comprises: acquiring ground measurement data of a target aircraft at a target moment; acquiring motion state parameters of the target aircraft corresponding to the ground-based measurement data; and generating a plurality of simulated optical images of the target aircraft according to the motion state parameters, wherein the change angle of the attitude angle of the target aircraft in any two adjacent simulated optical images in the plurality of simulated optical images is the target angular velocity.

Optionally, determining, as the target simulation image, a simulation optical image with the largest similarity to the target actually-measured optical image in the plurality of simulation optical images includes: acquiring a first characteristic value of each simulated optical image and a second characteristic value of a target actual measurement optical image; obtaining the similarity between the first characteristic value and the second characteristic value of each simulated optical image to obtain a plurality of similarities; and determining the simulated optical image corresponding to the maximum similarity in the multiple similarities as a target simulated image.

Optionally, the obtaining the first characteristic value of each simulated optical image comprises: and acquiring a first characteristic value of a solar array area and a first characteristic value of a cabin area of each simulation optical image, wherein the solar array area corresponds to the solar array of the target aircraft, and the cabin area corresponds to the cabin of the target aircraft.

Optionally, the obtaining the first characteristic values of the solar panel region and the nacelle region of each simulated optical image includes: and acquiring characteristic values of each simulated optical image, including the long axis direction angle and the short axis direction angle of the circumscribed rectangle of the solar array region, and the characteristic values of the long axis direction angle and the short axis direction angle of the circumscribed rectangle of the cabin region.

Optionally, the obtaining a second characteristic value of the measured target optical image includes: and responding to a target instruction generated by target operation on a solar array area and a cabin area of the target actual measurement optical image to acquire a second characteristic value, wherein the solar array area corresponds to the solar array of the target aircraft, and the cabin area corresponds to the cabin of the target aircraft.

Optionally, the obtaining, on the solar array region and the cabin region of the actually measured optical image of the target, a target instruction generated by responding to a target operation, a second feature value includes: on a solar array panel area and a cabin area of a target actual measurement optical image, a target instruction generated by target operation is responded, and characteristic values including a long axis direction angle and a short axis direction angle of a circumscribed rectangle of the solar array panel area and characteristic values including a long axis direction angle and a short axis direction angle of a circumscribed rectangle of the cabin area are obtained.

Optionally, obtaining a similarity between the first characteristic value and the second characteristic value of each simulated optical image, and obtaining a plurality of similarities includes: and obtaining the similarity between the first characteristic value and the second characteristic value of each simulated optical image through the Euclidean distance between the first characteristic value and the second characteristic value of each simulated optical image to obtain a plurality of similarities.

Optionally, determining the simulated optical image corresponding to the maximum similarity among the multiple similarities as the target simulated image includes: and determining the simulated optical image corresponding to the first characteristic value with the minimum Euclidean distance between the second characteristic values as a target simulated image, wherein the similarity of the simulated optical image corresponding to the first characteristic value with the minimum Euclidean distance between the second characteristic values is the maximum similarity in the plurality of similarities.

Optionally, before acquiring the plurality of simulated optical images and the one measured optical image of the target aircraft at the target time, the method further comprises: acquiring a plurality of actually measured optical images shot in a target observation arc section, wherein the corresponding moments of the plurality of actually measured optical images are different; determining an actual measurement optical image with the moment as a first moment in the plurality of actual measurement optical images as a target actual measurement optical image, and determining the first moment as a target moment, wherein the time of a target observation arc section comprises the first moment; determining first attitude information of the target aircraft in the target simulation image as second attitude information of the target aircraft at the target moment comprises the following steps: and determining first attitude information of the target aircraft in the target simulation image as second attitude information of the target aircraft at the first moment, wherein the second attitude information is used for indicating the actually measured attitude of the target aircraft at the first moment.

Optionally, after determining the first attitude information of the target aircraft in the target simulation image as the second attitude information of the target aircraft at the first time, the method further includes: determining the actual measurement optical image with the moment as a second moment in the plurality of actual measurement optical images as a target actual measurement optical image, and determining the second moment as a target moment, wherein the time of a target observation arc section comprises the second moment, and the second moment is the next moment of the first moment; determining first attitude information of the target aircraft in the target simulation image as second attitude information of the target aircraft comprises the following steps: and determining the first attitude information of the target aircraft in the target simulation image as the second attitude information of the target aircraft at the second moment.

To achieve the above object, according to an aspect of the present invention, there is also provided an aircraft attitude determination device based on an optical image. The device includes: the acquiring unit is used for acquiring a plurality of simulated optical images and a target actual measurement optical image of the target aircraft at a target moment; the first determining unit is used for determining the simulated optical image with the maximum similarity with the target actual measurement optical image in the plurality of simulated optical images as a target simulated image; and the second determining unit is used for determining first attitude information of the target aircraft in the target simulation image as second attitude information of the target aircraft at the target moment, wherein the first attitude information is used for indicating the attitude displayed by the target aircraft in the target simulation image, and the second attitude information is used for indicating the actual measurement attitude of the target aircraft at the target moment.

In order to achieve the above object, according to an aspect of the present invention, there is also provided a storage medium. The storage medium has stored therein a computer program, wherein the computer program is arranged to execute the method for determining the attitude of a target aircraft based on an optical image according to an embodiment of the invention when running.

According to the invention, a plurality of simulated optical images and a target actual measurement optical image of the target aircraft at the target moment are obtained; determining the simulated optical image with the maximum similarity with the target actual measurement optical image in the plurality of simulated optical images as a target simulated image; and determining first attitude information of the target aircraft in the target simulation image as second attitude information of the target aircraft at the target moment, wherein the first attitude information is used for indicating the attitude displayed by the target aircraft in the target simulation image, and the second attitude information is used for indicating the actual measurement attitude of the target aircraft at the target moment. The simulation optical image of the aircraft is generated through simulation, then the simulation optical image which is closest to the characteristic value of the actually-measured optical image is selected, the attitude information of the aircraft of the closest simulation optical image is used as the attitude information of the aircraft, the purpose of determining the attitude of the aircraft based on the optical image is achieved, the technical problem that the attitude of the aircraft is difficult to estimate through an optical externally-measuring means in an actual space flight test task is solved, and the attitude measurement requirement of the actual space flight task is met.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the invention and not to limit the invention. In the drawings:

FIG. 1 is a flow chart of a method for optical image-based determination of the attitude of a target aircraft in accordance with an embodiment of the present invention;

FIG. 2 is a flow chart of a method for estimating the attitude of a target aircraft based on optical images in accordance with an embodiment of the present invention;

FIG. 3 is a schematic illustration of components of a three-dimensional model of a target aircraft (exemplified by Tiangong No. one) in accordance with an embodiment of the present invention;

FIG. 4 is a schematic diagram of a body coordinate system and a track RTN coordinate system of a target aircraft during three-axis ground-to-ground flight according to an embodiment of the present invention;

FIG. 5 is a schematic diagram of a measured optical image fit using a bounding rectangle according to an embodiment of the present invention;

FIG. 6 is a diagram illustrating the main parameters of an OpenGL perspective projection pyramid, according to an embodiment of the present invention;

FIG. 7 is a schematic diagram illustrating the comparison of STK simulation results with OpenGL-based optical imaging simulation results of the embodiment, taking three-axis ground-to-ground flight of the target aircraft as an example, according to the embodiment of the invention;

FIG. 8 is a schematic diagram of a simulated optical image fitted with a circumscribed rectangular bounding box according to an embodiment of the present invention; and

fig. 9 is a schematic diagram of an optical image-based target aircraft attitude determination apparatus according to an embodiment of the present invention.

Wherein the drawings include the following reference numerals:

1. solar panels (blue); 2. resource bin (grey); 3. experimental cabin (grey); 4. cutting noodles far; 5. perspective projection cone; 6. and (5) approaching the cutting surface.

Detailed Description

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings.

In order to make the technical solutions better understood by those skilled in the art, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only partial embodiments of the present application, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

It should be noted that the terms "first," "second," and the like in the description and claims of this application and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It should be understood that the data so used may be interchanged under appropriate circumstances such that embodiments of the application described herein may be used. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

Example 1

The embodiment of the invention provides a target aircraft attitude determination method based on an optical image.

FIG. 1 is a flow chart of a method for optical image-based determination of the attitude of a target aircraft in accordance with an embodiment of the present invention. As shown in fig. 1, the method comprises the steps of:

and S102, acquiring a plurality of simulated optical images and a target actual measurement optical image of the target aircraft at the target moment.

In the technical solution provided in step S102 of the present invention, the target aircraft is an aircraft with a to-be-determined attitude, the target time may be a certain time within a certain observation arc, the plurality of simulated optical images may be a plurality of simulated optical images of ground-based optical imaging, and a computer simulation technique may be used to perform simulation using an Open Graphics Library (opengraphics Library, abbreviated as OpenGL) according to parameters such as ephemeris data and ground-based optical telescope site coordinates of the aircraft, so as to generate a simulated optical image of the aircraft, where the simulated optical image is also a simulated optical image of ground-based optical imaging, is similar to human vision, has characteristics of intuition and easy understanding, and can obtain information such as an on-track state of the target from the image. The embodiment can also be used for measuring the longitude, the latitude and the altitude of the geodetic coordinate of the station and the corresponding time t of a target actual measurement optical image₁Position of the aircraft (Rx)₁，Ry₁，Rz₁) Velocity (Vx)₁，Vy₁，Vz₁) The attitude angle of the aircraft, the field angle of the ground-based optical telescope, the number of pixels, the size of a single pixel and the like, and the simulation optical image of the aircraft is generated by simulating with OpenGL.

Optionally, the plurality of simulated optical images of this embodiment are a plurality of simulated optical images obtained by changing the attitude angle in a stepwise manner on the basis of the initial attitude angle of the aircraft. The target actual measurement optical image can be an image obtained by actually shooting the aircraft and is an actual measurement adaptive optical image. Under the condition that the aircraft meets certain observation illumination conditions, an image sequence of the aircraft in a visible light wave band can be shot through the ground-based adaptive optical telescope, and the image sequence can distinguish the outlines of a solar cell panel and a cabin of the aircraft.

And step S104, determining the simulated optical image with the maximum similarity with the target actual measurement optical image in the plurality of simulated optical images as the target simulated image.

In the technical solution provided in step S104 of the present invention, after acquiring a plurality of simulated optical images of the target aircraft at the target time and one target actual measurement optical image, a simulated optical image with the maximum similarity to the target actual measurement optical image in the plurality of simulated optical images is determined as the target simulated image.

After a plurality of simulated optical images and a target actual measurement optical image of the target aircraft at the target moment are obtained, the similarity between each simulated optical image and the target actual measurement optical image can be obtained to obtain a plurality of similarities, and the simulated optical image corresponding to the maximum similarity in the similarities is determined as the target simulated image, namely, the target simulated image is the simulated optical image which is closest to the target actual measurement optical image in the simulated optical images. And determining the simulated optical image with the maximum similarity with the target actual measurement optical image in the plurality of simulated optical images as the target simulated image.

Optionally, in this embodiment, the characteristic value of the target actual measurement optical image is extracted through manual operation, the characteristic value of the simulated optical image is calculated through automatic processing, and the simulated optical image closest to the target actual measurement optical image is selected as the target simulated image through comparison, loop processing, retrieval and other modes between the characteristic value of the target actual measurement optical image and the characteristic of the simulated optical image.

And S106, determining the first attitude information of the target aircraft in the target simulation image as the second attitude information of the target aircraft at the target moment.

In the technical solution provided in step S106 of the present invention, after determining a simulated optical image with the largest similarity to the target actual measurement optical image in the plurality of simulated optical images as the target simulated image, first attitude information of the target aircraft in the target simulated image is determined as second attitude information of the target aircraft at the target time, where the first attitude information is used to indicate an attitude displayed by the target aircraft in the target simulated image, and the second attitude information is used to indicate an actual measurement attitude of the target aircraft at the target time.

After determining the simulated optical image with the greatest similarity to the target actual measurement optical image in the plurality of simulated optical images as the target simulated image, the embodiment may obtain first attitude information in the target simulated image, where the first attitude information is used to indicate an attitude of the target aircraft displayed in the target simulated image, for example, to indicate an on-orbit flight attitude of the target aircraft displayed in the target simulated image, and the first attitude information may be an attitude angle. In the attitude angles (alpha, beta, gamma), the pitch angle alpha is the included angle of the projection of the main body ox shaft ON the TON plane after the target rotates anticlockwise around the ON shaft in the orbital coordinate system (RTN) coordinate system; the yaw angle beta is an included angle between the projection of the axis ox of the body on the TON plane and the OT axis after the target rotates anticlockwise around the OR axis in the RTN coordinate system; the rolling angle gamma is an included angle between the body oy axis and the projection of the body oy axis on the TON plane after the target rotates anticlockwise around the OT axis. The origin of the RTN coordinate system of the track is the center of mass of the target aircraft, the R axis is used for representing the radial direction from the geocenter to the center of mass, the T axis is perpendicular to the R axis in the track plane and used for representing the motion direction of the target aircraft, and the N axis is used for representing the normal direction of the track plane.

After the first attitude information in the target simulation image is obtained, the first attitude information is determined as second attitude information of the target aircraft at the target moment, the second attitude information is used for indicating the actual measurement attitude of the target aircraft at the target moment and can be an attitude angle, namely, the attitude angle of the aircraft of the target simulation image is used as the attitude angle of the aircraft of the actual measurement optical image, so that the problem that the attitude calculation of the aircraft is directly carried out based on the actual measurement optical image, and the low accuracy of attitude estimation is caused because the resolution of the actual measurement image is low and effective characteristic points cannot be extracted is solved.

In the embodiment, a plurality of simulated optical images and a target actual measurement optical image of a target aircraft at a target moment are obtained; determining the simulated optical image with the maximum similarity with the target actual measurement optical image in the plurality of simulated optical images as a target simulated image; and determining first attitude information of the target aircraft in the target simulation image as second attitude information of the target aircraft at the target moment, wherein the first attitude information is used for indicating the attitude displayed by the target aircraft in the target simulation image, and the second attitude information is used for indicating the actual measurement attitude of the target aircraft at the target moment. Because the simulated optical image of the aircraft is generated through simulation, the simulated optical image which is closest to the characteristic value of the target actual measurement optical image is selected, and the attitude information of the aircraft of the closest simulated optical image is used as the attitude information of the aircraft, the aim of determining the attitude of the aircraft is fulfilled, the problem that the attitude of the aircraft is difficult to estimate through an optical external measurement means in an actual space flight test task is solved, and the attitude measurement requirement of the actual space flight task is met.

As an alternative embodiment, the step S102 of acquiring a plurality of simulated optical images of the target aircraft at the target time includes: acquiring ground measurement data of a target aircraft at a target moment; acquiring motion state parameters of the target aircraft corresponding to the ground-based measurement data; and generating a plurality of simulated optical images of the target aircraft according to the motion state parameters, wherein the change angle of the attitude angle of the target aircraft in any two adjacent simulated optical images in the plurality of simulated optical images is the target angular velocity.

In this embodiment, in acquiring the plurality of simulated optical images of the target aircraft at the target time, the ground based survey data of the target aircraft at the target time may be acquired. The method comprises the steps of obtaining movement state parameters of a target aircraft corresponding to ground-based measurement data after the ground-based measurement data are obtained, carrying out precise orbit determination on the target aircraft through the ground-based measurement data of the target aircraft, wherein in the process of carrying out the precise orbit determination on the target aircraft, perturbation force influencing factors mainly comprise earth mass point gravity perturbation, non-spherical gravity perturbation, atmospheric resistance perturbation, sun-moon gravity perturbation, sunlight pressure perturbation and the like, and orbit determination precision is superior to hundred meter magnitude. The motion state of the target aircraft corresponding to the generation time of each actually-measured optical image is calculated by an ephemeris interpolation method, the motion state of the target aircraft at any time in the past, the present and the future can be calculated and forecasted, the motion state comprises position parameters, speed parameters and the like, and therefore accurate relative geometric relation parameters are provided for generating the simulated optical image of the target aircraft and carrying out attitude estimation on the target aircraft.

After obtaining the motion state parameters of the target aircraft corresponding to the ground-based measurement data, generating a plurality of simulated optical images of the target aircraft according to the motion state parameters, and generating a plurality of simulated optical images of the target aircraft by using OpenGL simulation according to the position parameters, the speed parameters, the attitude angle, the field angle, the number of pixels, the size of a single pixel, the longitude and latitude of geodetic coordinates of a measuring station, the altitude, the ephemeris data, the site coordinates of a ground-based optical telescope and other parameters of the target aircraft through a computer simulation technology, wherein the change angle of the attitude angle of the target aircraft in any two adjacent simulated optical images in the plurality of simulated optical images is the target angular velocity, for example, the target angular velocity delta alpha can take an angle value between 0.2 and 0.5, and can be based on the initial attitude angle of the target aircraft, the attitude angle of the target aircraft in the simulated optical image is changed in a stepping mode, so that a plurality of simulated optical images are obtained, the simulated optical image with the maximum similarity with the target actual measurement optical image in the plurality of simulated optical images is determined as the target simulated image, the first attitude information of the target aircraft in the target simulated image is determined as the second attitude information of the target aircraft at the target moment, the purpose of determining the attitude of the aircraft based on the optical image is achieved, the attitude estimation precision of the aircraft is improved, the effect of estimating the attitude of the aircraft by an optical external measurement means in an actual space flight test task is achieved, and the attitude measurement requirement of the actual space flight task is met.

Optionally, the optical imaging simulation in this embodiment uses OpenGL based on that the perspective projection imaging model of OpenGL is similar to the imaging model of the optical imaging system. The size of the image, the target posture and the number of occupied pixels are determined by the geometric size and the three-dimensional structure of the target, the relative geometric relation between the target and an imaging system, a geometric imaging model and other factors.

Optionally, the embodiment uses a third-party software Satellite simulation Kit (STK) to verify the correctness of the optical imaging simulation method and the result in the embodiment. The STK can be added with a sensor object for the ground station to point to a satellite target, and the target attitude in the sensor field of view can be displayed in the STK three-dimensional display area by manually editing and controlling the observation visual angle and the target attitude rotation of the three-dimensional scene, wherein the target attitude is consistent with the target attitude seen by the ground station optical equipment. Therefore, the correctness of the geometric imaging simulation can be verified by comparing whether the target posture in the field of view of the sensor at a certain moment is consistent with the target posture in the generated image.

As an alternative implementation manner, in step S104, determining, as the target simulation image, the simulation optical image with the largest similarity to the target measured optical image in the plurality of simulation optical images includes: acquiring a first characteristic value of each simulated optical image and a second characteristic value of a target actual measurement optical image; obtaining the similarity between the first characteristic value and the second characteristic value of each simulated optical image to obtain a plurality of similarities; and determining the simulated optical image corresponding to the maximum similarity in the multiple similarities as a target simulated image.

In this embodiment, after acquiring a plurality of simulated optical images of the target aircraft at the target time and one measured optical image of the target, a first characteristic value of each simulated optical image may be acquired, where the first characteristic value may be a characteristic value of the target aircraft in a certain region in the simulated optical image, and the simulated optical image may distinguish different regions by different colors. For example, the solar panel is blue, and the resource cabin and the experiment cabin are both gray. And acquiring a second characteristic value of the target measured optical image, wherein the second characteristic value may be a characteristic value of the target aircraft in a certain region in the target measured optical image, for example, a characteristic value in a solar panel region and a cabin region.

After a first characteristic value of each simulated optical image and a second characteristic value of a target actual measurement optical image are obtained, the similarity between the first characteristic value and the second characteristic value of each simulated optical image is obtained, a plurality of similarities are obtained, the similarities can be used for indicating the similarity between each simulated optical image and the target actual measurement optical image, the simulated optical image corresponding to the maximum similarity in the similarities is determined as a target simulated image, further, first attitude information of the target aircraft in the target simulated image is determined as second attitude information of the target aircraft at the target moment, the purpose of determining the attitude of the aircraft based on the optical image is achieved, the attitude estimation precision of the aircraft is improved, and the effect of estimating the attitude of the aircraft by an optical external measurement means in an actual space flight test task is achieved, the attitude measurement requirement of the actual space flight task is met.

As an alternative embodiment, the obtaining the first characteristic value of each simulated optical image includes: and acquiring a first characteristic value of a solar array area and a first characteristic value of a cabin area of each simulation optical image, wherein the solar array area corresponds to the solar array of the target aircraft, and the cabin area corresponds to the cabin of the target aircraft.

In this embodiment, the simulated optical image is segmented into a solar array region, a cabin region consisting of a resource cabin and an experimental cabin. When the first characteristic value of each simulated optical image is obtained, the first characteristic value of the solar array area and the first characteristic value of the cabin area of each simulated optical image can be obtained, the solar array area of each simulated optical image can be used for indicating the solar array of the target aircraft, and the cabin area of each simulated optical image can be used for indicating the cabin of the target aircraft. Optionally, common region descriptors include region area, centroid, topological properties, texture, invariant moment, etc., without any limitation herein.

As an alternative embodiment, the obtaining the first characteristic values of the solar panel region and the cabin region of each simulated optical image includes: and acquiring characteristic values of each simulated optical image, including the long axis direction angle and the short axis direction angle of the circumscribed rectangle of the solar array region, and the characteristic values of the long axis direction angle and the short axis direction angle of the circumscribed rectangle of the cabin region.

In this embodiment, when the first characteristic values of the solar array region and the cabin region of each simulated optical image are obtained, the characteristic values of each simulated optical image, including the major axis direction angle and the minor axis direction angle of the circumscribed rectangle of the solar array region, are obtained, where the major axis direction angle of the circumscribed rectangle of the solar array region is used to indicate the extending direction of the region.

Optionally, in this embodiment, a computer program automatic processing mode is adopted, the simulated optical image is automatically image-segmented according to different material colors, the simulated optical image is divided into a blue solar cell panel area and a gray cabin area, and then index parameters such as a long axis direction angle and a short axis direction angle are directly calculated for the segmented sailboard and cabin area.

Optionally, in this embodiment, the three-dimensional model file of the target aircraft is subjected to model format conversion, editing, processing and other processing, key information such as a geometric size of the three-dimensional model and a body coordinate system direction is edited and stored as a 3DS format file, the three-dimensional modeling software 3DS MAX may be used for performing the model format conversion, editing, processing and processing, the geometric size of the three-dimensional model and the direction of the body coordinate axis are edited, different components in the target aircraft are represented and distinguished by different colors, for example, the solar cell panel is blue, the resource cabin and the experiment cabin are both gray, and the scattering characteristic of the set material to the light source is diffuse reflection.

As an optional implementation manner, acquiring the second characteristic value of the measured optical image of the target includes: and responding to a target instruction generated by target operation on a solar array area and a cabin area of the target actual measurement optical image to acquire a second characteristic value, wherein the solar array area corresponds to the solar array of the target aircraft, and the cabin area corresponds to the cabin of the target aircraft.

In the embodiment, because the actually measured optical image of the target aircraft has the characteristics of imaging blur and low contrast, only the approximate outlines of the solar sailboard and the main body can be distinguished, and the centroid of the area is difficult to accurately calculate. The target characteristic points cannot be accurately extracted and processed only by using the actually measured optical image, so that a method for processing the actually measured optical image by manual operation is adopted. When a second characteristic value of the target actual measurement optical image is obtained, image segmentation is carried out on the target actual measurement optical image to obtain a solar sailboard area and a cabin area of the target actual measurement optical image, the solar sailboard area of the target actual measurement optical image corresponds to the solar sailboard of the target aircraft, and the cabin area of the target actual measurement optical image corresponds to the cabin of the target aircraft. And responding to a target instruction generated by target operation on the solar array area and the cabin area of the target actual measurement optical image to obtain a second characteristic value, wherein the target operation is an operation performed manually.

As an optional implementation manner, the acquiring, on the solar panel area and the cabin area of the actually measured optical image of the target, the target instruction generated in response to the target operation includes: on a solar array panel area and a cabin area of a target actual measurement optical image, a target instruction generated by target operation is responded, and characteristic values including a long axis direction angle and a short axis direction angle of a circumscribed rectangle of the solar array panel area and characteristic values including a long axis direction angle and a short axis direction angle of a circumscribed rectangle of the cabin area are obtained.

Optionally, in the embodiment, the characteristic values of the major axis direction angle and the minor axis direction angle of the circumscribed rectangle including the solar array area and the characteristic values of the major axis direction angle and the minor axis direction angle of the circumscribed rectangle including the cabin area are obtained, polygonal fitting may be performed on the array area and the cabin area after the target actual measurement optical image is segmented, mainly by using a method of bounding a box with the circumscribed rectangle, and finally, the indexes of the major axis direction angle, the minor axis direction angle, and the like of the circumscribed rectangle of the array area and the cabin area are calculated.

As an optional implementation manner, obtaining a similarity between the first characteristic value of each simulated optical image and the second characteristic value of the measured optical image, and obtaining a plurality of similarities includes: and obtaining the similarity between the first characteristic value of each simulated optical image and the second characteristic value of the actually measured optical image through the Euclidean distance between the first characteristic value of each simulated optical image and the second characteristic value of the actually measured optical image, so as to obtain a plurality of similarities.

The similar attitude model can be expressed as a group of similar characteristic vectors in a characteristic vector space, the embodiment performs similarity matching between the simulated optical image and the measured optical image, and can calculate a spatial distance between a characteristic value of the measured optical image and a characteristic value of the simulated optical image in a multi-dimensional characteristic space, wherein the spatial distance can be a Euclidean distance, and the similarity between the simulated optical image and the measured optical image is measured through the Euclidean distance.

As an optional implementation manner, determining the simulated optical image corresponding to the maximum similarity among the multiple similarities as the target simulated image includes: and determining the simulated optical image corresponding to the first characteristic value with the minimum Euclidean distance between the second characteristic values of the actually measured optical image as the target simulated image, wherein the similarity of the simulated optical image corresponding to the first characteristic value with the minimum Euclidean distance between the second characteristic values is the maximum similarity in the multiple similarities.

In this embodiment, when the simulated optical image corresponding to the largest similarity among the plurality of similarities is determined as the target simulated image, the simulated optical image corresponding to the first feature value having the smallest euclidean distance between the second feature values of the actually measured optical image is determined as the target simulated image. Alternatively, let X be (X) for the feature vectors of the actual measurement optical image and the simulated optical image, respectively₁，x₂，...，x_n)、Y＝(y₁，y₂，...，y_n) Then, the expression of the euclidean distance is:

alternatively, the embodiment automatically changes the target pose, generates a plurality of simulated optical images, and in the process of automatically processing and calculating the characteristic values, different weight values can be given to different characteristic values,the weighted Euclidean distance measure can be used for exerting influence on the result according to the feedback condition

The expression is carried out, wherein,

weight values for representing different feature values.

As an optional implementation manner, before acquiring a plurality of simulated optical images and a target measured optical image of the target aircraft at the target time in step S102, the method further includes: acquiring a plurality of actually measured optical images shot in a target observation arc section, wherein the corresponding moments of the plurality of actually measured optical images are different; determining an actual measurement image with a first moment in the plurality of actual measurement optical images as a target actual measurement optical image, and determining the first moment as a target moment, wherein the time of a target observation arc section comprises the first moment; step S106, determining the first attitude information of the target aircraft in the target simulation image as the second attitude information of the target aircraft at the target moment, wherein the step S comprises the following steps: and determining first attitude information of the target aircraft in the target simulation image as second attitude information of the target aircraft at the first moment, wherein the second attitude information is used for indicating the actually measured attitude of the target aircraft at the first moment.

In this embodiment, before acquiring a plurality of simulated optical images and a target actual measurement optical image of the target aircraft at a target time, a plurality of actual measurement optical images captured in a target observation arc are acquired, for example, N actual measurement optical images of the target aircraft captured in a certain observation arc through a ground-based optical telescope are acquired, and an imaging time corresponding to each actual measurement optical image is t₁、t₂…、t_N. After acquiring a plurality of actually measured optical images shot in a target observation arc segment, determining an actually measured optical image with a time being a first time in the plurality of actually measured optical images as a target actually measured optical image, and determining the first time as a target time, for example, determining the time being t in the plurality of images as the target time₁Determining the actual measurement optical image of the moment as the target actual measurement optical image, and determining t₁The time is determined as a target time, and then the first attitude information of the target aircraft in the target simulation image is determined as the second attitude information of the target aircraft at the first time, wherein the second attitude information is used for indicating the actual measurement attitude of the target aircraft at the first time, so that the effect of the accuracy of estimating the attitude of the aircraft is improved.

As an optional implementation, after determining the first attitude information of the target aircraft in the target simulation image as the second attitude information of the target aircraft at the first time, the method further includes: determining the actual measurement optical image with the moment as a second moment in the plurality of actual measurement optical images as a target actual measurement optical image, and determining the second moment as a target moment, wherein the time of a target observation arc section comprises the second moment, and the second moment is the next moment of the first moment; step S106, determining the first attitude information of the target aircraft in the target simulation image as the second attitude information of the target aircraft comprises the following steps: and determining the first attitude information of the target aircraft in the target simulation image as the second attitude information of the target aircraft at the second moment.

In this embodiment, after determining the first attitude information of the target aircraft in the target simulation image as the second attitude information of the target aircraft at the first time, the measured optical image with the time being the second time in the plurality of measured optical images is determined as the target measured optical image, and the second time is determined as the target time, for example, the time being t in the plurality of images is determined as the target time₂Determining the actual measurement optical image of the moment as the target actual measurement optical image, and determining t₂Determining the time as a target time, further determining first attitude information of the target aircraft in the target simulation image as second attitude information of the target aircraft at a second time, and so on until the attitude estimation of the plurality of measured optical images in the target observation arc section is finished, and obtaining an attitude information sequence of the target aircraft in the target observation arc section, for example, obtaining an attitude angle sequence (alpha)_i，β_i，γ_i)，According to the sequence of attitude angles (alpha)_i，β_i，γ_i) And calculating the change situation of the attitude of the target aircraft along with time to obtain the rotation angular speeds of the target aircraft in the yaw, pitch and roll directions.

The embodiment provides an attitude estimation method of an aircraft based on an optical image aiming at the characteristics of an optical image, which simulates and generates a ground-based optical simulation image of a target aircraft through a computer simulation technology, then extracting the characteristic value of the actually measured optical image through manual operation, automatically processing and calculating the characteristic value of the simulated optical image, selecting a simulated optical image which is closest to the characteristic value of the actual measurement optical image by means of characteristic value comparison and the like, taking the attitude angle of the target aircraft of the simulated optical image as the attitude angle of the target aircraft of the actual measurement optical image, therefore, the on-orbit flight attitude of the target aircraft is conveniently and quickly calculated, a high-precision attitude estimation scheme is provided, the effect of estimating the attitude of the aircraft by an optical external measurement means in an actual space flight test task is achieved, and the attitude measurement requirement of the actual space flight task is met.

Example 2

The technical solution of the present invention will be described below with reference to preferred embodiments.

In the embodiment, the target aircraft is precisely determined according to the measured data of the target aircraft, and the position and the speed of the target aircraft corresponding to the generation time of each measured optical image are calculated by an ephemeris interpolation method; simulating and generating a ground-based optical simulation image of the target aircraft by using OpenGL according to parameters such as ephemeris data, ground-based optical telescope station coordinates and the like of the target aircraft through a computer simulation technology; extracting characteristic values of the actually measured optical image in a manual operation selection mode, manually selecting a solar array area and a cabin area of the target aircraft in the actually measured optical image respectively, and then calculating a long axis direction angle and a short axis direction angle of a rectangle circumscribed by the two areas; calculating a characteristic value of a simulated optical image in a computer automatic processing mode, changing the attitude angle of the target aircraft in a stepping mode on the basis of the initial attitude angle of the target aircraft, respectively and automatically calculating a long axis direction angle and a short axis direction angle of a blue solar panel area and a gray cabin body area in the simulated optical image, and selecting the simulated optical image with the minimum Euclidean distance from the characteristic value of the actually measured optical image, thereby obtaining the attitude angle of the target aircraft corresponding to the actually measured optical image; and finally, carrying out statistical analysis on the attitude angle parameters of the target aircraft in the observation arc section, and calculating the change condition of the attitude of the target aircraft.

FIG. 2 is a flow chart of a method for estimating the attitude of a target aircraft based on ground-based optical images in accordance with an embodiment of the present invention. As shown in fig. 2, the method comprises the steps of:

step S201, editing, processing and saving the three-dimensional model file in the 3ds format of the target aircraft.

According to the embodiment, the three-dimensional modeling software 3DS MAX is used for model format conversion, editing, processing and processing according to the three-dimensional model file of the target aircraft in the Proe format provided by the industrial department, the geometric dimension of the three-dimensional model and the direction of the coordinate axis of the body are edited, and different materials are used for representing and distinguishing different parts of the target aircraft.

FIG. 3 is a schematic diagram of components of a three-dimensional model of a target aircraft (exemplified by Tiangong No. one) in accordance with an embodiment of the present invention. As shown in fig. 3, as an example of the target aircraft, skong No. one is a passive target in a rendezvous and docking test, a solar panel 1 of the target aircraft is blue, a resource cabin 2 and an experiment cabin 3 are both gray, and a scattering characteristic of a set material to a light source is diffuse reflection, so that a solar panel and a cabin body of the target aircraft can be automatically distinguished through color value judgment in a simulated optical image, and characteristic values of two areas are calculated.

And S202, performing precise orbit determination on the target aircraft, and calculating the position and the speed of each actually-measured imaging moment in the observation arc section.

In this embodiment, the ground-based survey data of the target aircraft is used to make a precise orbit determination, calculate and forecast the motion state (position parameters, velocity parameters) of the target at any time in the past, current and future periods of time, and provide accurate relative geometric relationship parameters for imaging simulation and attitude estimation. The perturbation force influence factors considered in the precise orbit determination process of the embodiment mainly comprise earth mass point gravity perturbation, non-spherical gravity perturbation, atmospheric resistance perturbation, sun and moon gravity perturbation, sunlight pressure perturbation and the like, and the orbit determination precision is superior to hectometer level.

This embodiment may use the J2000 equatorial-inertial frame, the orbital frame (RTN frame), the target aircraft's frame, and the euler angles to calculate and describe the target aircraft's position, velocity, and attitude parameters. The origin of the J2000 geocentric coordinate system is the earth centroid, the reference plane is the earth equatorial plane at the moment J2000.0, the Z axis points to the north pole in the positive direction, and the X axis points to the vernality point in the positive direction.

Fig. 4 is a schematic diagram of a body coordinate system and a track RTN coordinate system of a target aircraft during three-axis ground-to-ground flight according to an embodiment of the present invention. As shown in fig. 4, the body coordinate system o-xyz of the target aircraft coincides with the RTN coordinate system when the three axes fly to the ground, the base plane xoz is a longitudinal symmetry plane, the roll axis ox points to the front of the body, and the oy axis is perpendicular to the base plane and parallel to the rotation axis of the solar panel. The normal direction of the front surface (provided with the solar cell pieces) of the solar cell sailboard of the target aircraft is parallel to the oz axis, and the rotation angle theta of the sailboard is 0 degree.

And step S203, manually calculating the characteristic value of the measured optical image of the ith target aircraft.

Because the actually measured optical image has the characteristics of low resolution and low contrast, only the approximate outlines of the solar sailboard and the main body can be distinguished, and the mass center of the area is difficult to accurately calculate. Only the actual measurement optical image cannot be used for accurately extracting the target characteristic points for processing, so that the embodiment adopts manual operation to process the actual measurement optical image, and manually calculates the characteristic value of the actual measurement optical image of the ith target aircraft. For the actually measured optical image, the image needs to be divided into cabin regions consisting of a solar panel region, a resource cabin and an experiment cabin of the target aircraft, and then characteristic values of the two regions are extracted. Optionally, the region descriptor of this embodiment includes region area, centroid, topological properties, texture, invariant moment, and the like. The method of the invention uses the long axis direction angle to describe the characteristics of the region. The extension direction (i.e., major axis direction angle) of the area object is:

wherein u is_pqThe (p + q) -order central moment for a region, p being 0, 1, 2, q being 0, 1, 2. The calculation method is as follows:

for a digital image f (x, y), its (p + q) order geometrical moment is:

wherein M, N are used to represent the length and width of the image, respectively.

The calculation method of the (p + q) order central moment comprises the following steps:

wherein the content of the first and second substances,

for representing the center of gravity of the image,

FIG. 5 is a schematic diagram of a measured optical image fit using a bounding rectangle according to an embodiment of the present invention. As shown in fig. 5, in this embodiment, a manual operation mode is adopted to preprocess the actual measurement optical image, then perform image segmentation on the preprocessed actual measurement optical image, then perform polygon fitting on the segmented windsurfing board area and the body area respectively, mainly perform fitting by using a method of enclosing a rectangular enclosure (such as a rectangular frame shown in fig. 5), and finally calculate indexes such as a major axis direction angle and a minor axis direction angle of a circumscribed rectangle of the windsurfing board and the body area.

And step S204, adjusting the attitude angle of the target aircraft, and generating a simulation optical image based on OpenGL.

The optical imaging simulation in this embodiment uses OpenGL based on the fact that the perspective projection imaging model of OpenGL is similar to the imaging model of the optical imaging system. The optical telescope projects a three-dimensional scene onto a two-dimensional plane of an imaging detector (CCD) through an optical lens group, and this process can be described by a camera imaging model.

Alternatively, when performing optical imaging simulation using OpenGL, the embodiment first calls the function glTranslate to generate the translation matrix T, and calls the function glRotate to generate the rotation matrix P to transform the coordinates of the point on the target model in the target satellite body coordinate system into the coordinates in the camera coordinate system. Where the values of the matrix P, T relate to the target distance and target pose angle at the time of imaging. Then call the function glFrustum (x)_l,x_r,y_b,y_t,Z_n,Z_f) Determining a perspective projection imaging range, finally setting the size of a screen display area by using a function glViewport (0,0, scrX, scrY), and establishing a corresponding relation between the coordinates after projection transformation and screen pixels.

For the ground-based optical telescope system, the physical width and height of the imaging plane of the area array imaging detector are set as l_x×l_yThe physical size of each pixel is dX × dY, and the number of pixels in the horizontal and vertical directions is l, respectively, regardless of the pixel pitch_x/dX、l_y/dY。

Fig. 6 is a schematic diagram of main parameters of an OpenGL perspective projection cone according to an embodiment of the present invention. As shown in fig. 6, a tracking arc segment corresponding to an image of an optical telescope is selected for analysis. In order to ensure that the resolution of the simulated optical image is consistent with the resolution of the real imaging result, the distances from the far clipping surface 4 and the near clipping surface 6 of the OpenGL perspective projection cone 5 to the point O of the original point are respectively set to be Z_f＝R、Z_nIf f, x is also required_l、x_r、y_b、y_tAre set to:

in addition, the number of pixels of the display area is the same as the number of CCD pixels, and there are:

scrX＝l_x/dX，scrY＝l_y/dY (5)

according to the observation distance, the embodiment calls a translation function glTranslate of OpenGL to generate a translation matrix T, and calls a rotation function glRotate to generate a rotation matrix R, so that the orientation of the camera coordinate system relative to the world coordinate system is determined. Calling perspective projection transformation function glFrustum (-l)_x/2,l_x/2,-l_y/2,l_y/2, f, r) determines the imaging range, i.e. the cone of view between the near and far clipping planes. To map the perspective projection imaging result onto the computer screen, the viewport transformation function glViewport (0,0, l) needs to be called_x/dX,l_y/dY) to set the size of the screen display area and to establish the correspondence between the projectively transformed coordinates and the screen pixels.

OpenGL of this embodiment is one of the best environments and tools for developing two-dimensional and three-dimensional graphics applications, and displays a three-dimensional object as a two-dimensional image on a computer screen mainly through processes of model transformation, perspective transformation, affine transformation, and the like. The perspective projection imaging process comprises the following steps: a certain point X on the three-dimensional model_s Y_s Z_s W_s]^TThrough the transformation of rotation, translation and the like of the model matrix, the perspective projection transformation of the projection matrix, and finally the normalization division and the viewport transformation of the matrix, the corresponding pixel coordinate [ x ] of the point on the screen is obtained_w y_w 1]^TThe process may be expressed as:

[x_w y_w 1]^T＝FPM·[X_s Y_s Z_s W_s]^T (6)

the optical telescope projects a three-dimensional scene onto a two-dimensional plane of the imaging detector CCD through the optical lens group, and the process can be described by a camera imaging model. Let the coordinate of a certain point P in space in world coordinate system be (X)_s,Y_s,Z_s) In a cameraThe image pixel coordinates of the corresponding image point on the imaging plane are (u, v), and then:

[u v 1]^T＝M₁M₂[X_s Y_s Z_s 1]^T (7)

wherein, the matrix M₁Related only to camera intrinsic parameters, M₂The extrinsic parameter matrix is determined by the orientation of the camera coordinate system relative to the world coordinate system.

From the above, it can be seen that the transformation process can be represented by a matrix, both in the case of optical imaging simulation using OpenGL and in the case of projection of a three-dimensional scene in a form using an optical telescope through an optical lens group. Therefore, by reasonably setting relevant parameters in OpenGL, a real camera imaging effect, namely, geometric imaging simulation, is simulated. The size and the posture of the target in the generated image are accurate, and the influence of factors such as different camera parameters, target postures, distances and the like on imaging can be reflected.

The embodiment can use a third-party software satellite simulation kit STK to verify the correctness of the optical imaging simulation method and the result in the method.

A Sensor object can be added to the ground station in the STK to point to a satellite target, and the target attitude in the Sensor field of view can be displayed in the STK three-dimensional display area by manually editing and controlling the observation angle of view and the target attitude rotation of the three-dimensional scene, wherein the attitude is consistent with the target attitude seen by the ground station optical equipment. Therefore, the accuracy of the geometric imaging simulation can be verified by comparing whether the target posture in the field of view of the STK Sensor at a certain moment is consistent with the target posture in the simulated optical image.

Fig. 7 is a schematic diagram illustrating comparison between STK simulation results and OpenGL-based optical imaging simulation results of the embodiment, taking three-axis ground-to-ground flight of the target aircraft as an example, according to the embodiment of the present invention. Assuming that the target aircraft is in a three-axis ground-to-ground positive flight attitude as shown in fig. 7, the attitude of the target aircraft in the field of view of the STK Sensor at the start of the arc segment and the simulated optical image result are shown as (a) and (b) in the upper row in fig. 7, respectively. The simulation result of the STK Sensor at the end of the arc segment and the simulation result are shown in (c) and (d) in the lower row of fig. 7, respectively. By comparing the postures of the target aircraft in the field of view of the STK Sensor, the target aircraft image generated by simulation is correct and consistent with the relative geometric relationship result of actual imaging.

In the embodiment, when OpenGL is used for imaging simulation, OpenGL-related parameters and a simulation flow are that, first, a translation matrix T is generated by calling a function glTranslate, and a rotation matrix P is generated by calling a function glRotate to transform coordinates of a point on a target model in a target satellite body coordinate system into coordinates in a camera coordinate system. Where the values of the matrix P, T are related to the R and alpha, beta values at the time of imaging. Then call the function glFrustum (x)_l,x_r,y_b,y_t,Z_n,Z_f) Determining a perspective projection imaging range, finally setting the size of a screen display area by using a function glViewport (0,0, scrX, scrY), and establishing a corresponding relation between the coordinates after projection transformation and screen pixels.

Step S205, calculating the characteristic value of the simulated optical image, comparing with the actual measurement optical image, and storing.

The simulation optical image of the embodiment also needs to divide the image into a cabin body area consisting of a solar sailboard area, a resource cabin and an experiment cabin, and then characteristic values of the two areas are extracted.

In the embodiment, a computer program automatic processing mode is adopted, and the simulated optical image is subjected to automatic image segmentation according to different material colors and is divided into a blue solar panel area and a gray cabin area. FIG. 8 is a schematic diagram of a simulated optical image fitted with a circumscribed rectangular bounding box according to an embodiment of the invention. As shown in fig. 8, polygonal fitting is performed on the divided windsurfing board area and the cabin area, and mainly a method of circumscribing a rectangular bounding box (a rectangular frame as shown in fig. 8) is used for fitting, and index parameters such as a major axis direction angle and a minor axis direction angle are calculated respectively and used as characteristic values of the simulated optical image.

In this embodiment, the similar pose model may be represented as a set of feature vectors that are close in feature vector space, the real pose modelThe task of similarity matching between the simulated optical image and the measured optical image in the embodiment is to calculate the spatial distance between the characteristic value of the measured optical image and the characteristic value of the simulated optical image in the multi-dimensional characteristic space. The embodiment can adopt Euclidean distance to measure the similarity of the simulation and the feature value of the measured image. Let the characteristic vectors of the actual measurement optical image and the simulated optical image be X ═ X (X)₁，x₂，...，x_n)、Y＝(y₁，y₂，...，y_n) Then, the expression of the euclidean distance is:

in the process of automatically changing the target posture to generate the simulated optical image and automatically processing and calculating the characteristic value, different weights with different sizes can be given to different characteristics to influence the result according to the feedback condition, and the weighted Euclidean distance metric can be expressed by the following formula:

wherein the content of the first and second substances,

are weight values of different features.

And step S206, calculating the attitude angle of the target aircraft of the ith image.

The simulated optical image closest to the characteristic value of the actual measurement optical image may be selected, the simulated optical image having the minimum euclidean distance from the characteristic value of the actual measurement optical image may be selected, and the attitude angle of the target aircraft of the simulated optical image may be set as the attitude angle of the target aircraft of the actual measurement optical image.

Let i be i +1, the execution continues with steps S203 to S206.

And step S207, counting and calculating the attitude change angle of the target aircraft in the observation arc section.

And carrying out statistical analysis on the attitude angle parameters of the target aircraft in the observation arc section, and calculating the attitude change condition of the target aircraft.

The following takes a single tracking arc segment of a ground-based optical telescope as an example to illustrate the steps of the technical scheme of the invention:

setting N image sequences of the target aircraft shot by the ground-based optical telescope in a certain observation arc section, wherein the imaging time corresponding to each image is t₁、t₂…、t_N。

A1: performing precise orbit determination on the target aircraft according to the external measurement data of the target aircraft, and calculating t by an ephemeris interpolation method₁、t₂…、t_NThe position and the speed of the target aircraft at the moment.

A2: and performing model format conversion, editing, processing and other processing on the three-dimensional model file of the target aircraft, editing key information such as the geometric dimension of the three-dimensional model and the body coordinate system direction, and storing the key information as a 3ds format file.

A3: according to the longitude, latitude and altitude of the geodetic coordinates of the measuring station and the corresponding time t of the 1 st image₁Target aircraft position (Rx)₁，Ry₁，Rz₁) Velocity (Vx)₁，Vy₁，Vz₁) The attitude angle (0,0, 0) of the target aircraft, the field angle of the ground-based optical telescope, the number of CCD pixels, the size of a single pixel and the like, and the simulation optical image of the ground-based optical imaging of the target aircraft is generated by using OpenGL.

A4: obtaining an initial value (alpha) of the in-orbit flight attitude angle of the target aircraft in the ith image_i，β_i，γ_i) Let the attitude angle search for the range A₀And 10 degrees, wherein when i is 1 and 2, the posture of the target aircraft is manually adjusted according to the subjective visual effect so that the simulated optical image is approximately consistent with the measured optical image. When i is greater than 2, take alpha_i＝α_i-1，β_i＝β_i-1，γ_i＝γ_i-1；

A5: according to the longitude, latitude, altitude of the geodetic coordinates of the measuring station and the corresponding time t of the ith image_iTarget aircraft position (Rx)_i，Ry_i，Rz_i) Velocity (Vx)_i，Vy_i，Vz_i) Target aircraft attitude angle (alpha)_i，β_i，γ_i) The imaging simulation is carried out according to the field angle of the ground-based optical telescope, the number of CCD pixels, the size of a single pixel and the like.

A6: calculating t_iAnd (3) similarity index delta omega of the actually measured optical image characteristic value and the simulated optical image characteristic value of the target aircraft at the moment.

A7：β_i、γ_iIs kept constant and only the attitude angle alpha is changed_iRespectively is alpha_i＝α_i+ m.DELTA.alpha, wherein DELTA.alpha is optionally 0.2 to 0.5, and M is + -1, + -2, …, + -M, respectively,

) Repeating the steps A5-A6 to obtain a group of similarity sequences delta omega₁。

A8: statistics of Δ ω₁Minimum value of (a) Δ ω_1minNote that the angle α at this time is set to α', and the process proceeds to step a 9.

A9: let alpha_i＝α’，γ_iThe value remains unchanged and only the attitude angle beta is changed_iHas a value of beta_i＝β_i+ p.DELTA.beta, wherein DELTA.beta is optionally 0.2 to 0.5, and P is + -1, + -2, …, + -P, respectively,

) Repeating the steps A5-A6 to obtain a group of similarity sequences delta omega₂。

A10: statistics of Δ ω₂Minimum value of Δ ω_2minRecord and Δ ω_2minThe corresponding angle β is set to β', and step a11 is entered.

A11: let alpha_i＝α’，β_iChanging only the attitude angle y ═ β_iHas a value of gamma_i＝γ_i+ q.DELTA.gamma, wherein DELTA.gamma may be 0.2-0.5 as the case may be), and Q is + -1, + -2, …, + -Q, respectively, (wherein

) Repeating the steps A5-A6 to obtain a group of similarity sequences delta omega₃。

A12: statistics of Δ ω₃Minimum value of (a) Δ ω_3minNote that γ is set as γ', and the process proceeds to step a 13.

A13: let A₀＝5°，(α_i，β_i，γ_i) Repeat steps a 5-a 12 for (α ', β ', γ ').

A14: the statistic result is delta omega₁、Δω₂、Δω₃Minimum value of Δ ω_minNote that the target attitude angle at this time is (α, β, γ). Output alpha_i＝α*、β_i＝β*、γ_iGo to step a 15.

A15: and if i is equal to i +1 and i is less than N, repeating the steps A3-A14.

A16: and if the i is equal to N, the estimation of the target aircraft attitude of the observation arc segment is finished, and the loop is ended. According to the sequence of the attitude angles (alpha) of the target aircraft_i，β_i，γ_i) Calculating the change situation of the attitude of the target aircraft along with time, and obtaining the rotating angular speeds of the target aircraft in the yaw, pitch and roll directions as follows:

the embodiment provides a target aircraft attitude estimation method based on an optical image aiming at the problem that the existing attitude estimation technology based on the optical image cannot meet the attitude estimation requirement of a target aircraft and aiming at the characteristics of an actual measurement optical image. The method can conveniently and quickly calculate the on-orbit flight attitude of the target aircraft according to the actually measured optical image, and provides a high-precision attitude estimation means.

By adopting the technical scheme, the target aircraft attitude estimation method is strong in pertinence and high in flexibility. The method can be practically applied to the civil and military fields including satellite load working state judgment, fault analysis, military target threat degree judgment, capture and the like.

The advantages of this embodiment are mainly manifested in the following aspects:

(1) the pertinence is strong, and the reliability is high. Compared with the prior attitude estimation method, the embodiment carries out the characteristic of the actual measurement optical image of the ground-based telescope.

The embodiment can select the target image characteristic value index with strong pertinence, and calculate the minimum Euclidean distance of the characteristic values of the simulated optical image and the actually measured optical image in a mode of combining manual operation and automatic processing. Third-party commercial software can be used for verifying the correctness and adaptability of the optical imaging simulation model and method in the method, and the effectiveness and accuracy of the attitude estimation method are further improved.

(2) The method of the embodiment is flexible, and the solar sailboards and the cabin body of the target aircraft are represented by different colors, so that the long axis direction angle and the short axis direction angle of the solar sailboards and the cabin body in the simulated optical image can be automatically processed and calculated without manual operation. In addition, the target aircraft can be checked and verified based on the actually measured image and the ephemeris data, and the imaging result of the ground-based optical telescope to the target aircraft can be generated in a pre-simulation mode by using the predicted attitude data.

It should be noted that the steps illustrated in the flowcharts of the figures may be performed in a computer system such as a set of computer-executable instructions and that, although a logical order is illustrated in the flowcharts, in some cases, the steps illustrated or described may be performed in an order different than presented herein.

Example 3

The embodiment of the invention also provides a target aircraft attitude determination device based on the optical image. It should be noted that the optical image-based target aircraft attitude determination apparatus of this embodiment may be used to execute the optical image-based target aircraft attitude determination method of the embodiment of the present invention.

Fig. 9 is a schematic diagram of an optical image-based target aircraft attitude determination apparatus according to an embodiment of the present invention. As shown in fig. 9, the apparatus includes: an acquisition unit 10, a first determination unit 20 and a second determination unit 30.

The acquiring unit 10 is configured to acquire a plurality of simulated optical images of the target aircraft at a target time and one actually-measured optical image of the target aircraft.

The first determining unit 20 is configured to determine, as the target simulation image, a simulation optical image with the largest similarity to the target actual measurement optical image among the plurality of simulation optical images.

The second determining unit 30 is configured to determine first attitude information of the target aircraft in the target simulation image as second attitude information of the target aircraft at the target time, where the first attitude information is used to indicate an attitude displayed by the target aircraft in the target simulation image, and the second attitude information is used to indicate an actual measurement attitude of the target aircraft at the target time.

Optionally, the obtaining unit 10 includes: the device comprises a first acquisition module and a generation module. The first acquisition module is used for acquiring the ground-based measurement data of the target aircraft at the target moment; acquiring motion state parameters of the target aircraft corresponding to the ground-based measurement data; and the generating module is used for generating a plurality of simulated optical images of the target aircraft according to the motion state parameters, wherein the change angle of the attitude angle of the target aircraft in any two adjacent simulated optical images in the plurality of simulated optical images is the target angular velocity.

Optionally, the first determination unit 20 includes: the device comprises a second acquisition module, a third acquisition module and a determination module. The second acquisition module is used for acquiring a first characteristic value of each simulated optical image and a second characteristic value of the target actual measurement optical image; the third acquisition module is used for acquiring the similarity between the first characteristic value of each simulated optical image and the second characteristic value of the actually-measured optical image to obtain a plurality of similarities; and the determining module is used for determining the simulated optical image corresponding to the maximum similarity in the multiple similarities as the target simulated image.

Optionally, the second obtaining module includes: the first obtaining submodule is used for obtaining a first characteristic value of a solar array area and a first characteristic value of a cabin area of each simulated optical image, wherein the solar array area corresponds to a solar array of the target aircraft, and the cabin area corresponds to a cabin of the target aircraft.

Optionally, the first obtaining sub-module is configured to perform the following steps to obtain the first characteristic values of the solar panel region and the cabin region of each simulated optical image: and acquiring characteristic values of each simulated optical image, including the long axis direction angle and the short axis direction angle of the circumscribed rectangle of the solar array region, and the characteristic values of the long axis direction angle and the short axis direction angle of the circumscribed rectangle of the cabin region.

Optionally, the second obtaining module includes: and the second obtaining submodule is used for responding to a target instruction generated by target operation on a solar array area and a cabin area of the target actual measurement optical image and obtaining a second characteristic value, wherein the solar array area corresponds to the solar array of the target aircraft, and the cabin area corresponds to the cabin of the target aircraft.

Optionally, the second obtaining sub-module is configured to perform the following steps to obtain, on the solar array region and the cabin region of the target measured optical image, a second characteristic value in response to a target instruction generated by a target operation: on a solar array panel area and a cabin area of a target actual measurement optical image, a target instruction generated by target operation is responded, and characteristic values including a long axis direction angle and a short axis direction angle of a circumscribed rectangle of the solar array panel area and characteristic values including a long axis direction angle and a short axis direction angle of a circumscribed rectangle of the cabin area are obtained.

Optionally, the third obtaining module includes: and the third obtaining submodule is used for obtaining the similarity between the first characteristic value of each simulated optical image and the second characteristic value of the actually measured optical image according to the Euclidean distance between the first characteristic value of each simulated optical image and the second characteristic value of the actually measured optical image, so as to obtain a plurality of similarities.

Optionally, the third obtaining sub-module is configured to perform the following steps to determine the simulated optical image corresponding to the maximum similarity among the multiple similarities as the target simulated image: and determining the simulated optical image corresponding to the first characteristic value with the minimum Euclidean distance between the second characteristic values of the actually measured optical image as a target simulated image, wherein the similarity of the simulated optical image corresponding to the first characteristic value with the minimum Euclidean distance between the second characteristic values of the actually measured optical image is the maximum similarity among the plurality of similarities.

Optionally, the apparatus further comprises: a first acquisition unit and a third determination unit. The first acquisition unit is used for acquiring a plurality of measured optical images shot in a target observation arc section before acquiring a plurality of simulated optical images and a target measured optical image of a target aircraft at a target moment, wherein the plurality of measured optical images correspond to different moments; the third determining unit is used for determining an actual measurement optical image with the moment being a first moment in the plurality of actual measurement optical images as a target actual measurement optical image and determining the first moment as a target moment, wherein the time of a target observation arc segment comprises the first moment; the second determination unit 30 is further configured to determine first attitude information of the target aircraft in the target simulation image as second attitude information of the target aircraft at the first time, where the second attitude information is used to indicate a measured attitude of the target aircraft at the first time.

Optionally, the apparatus further comprises: a fourth determining unit, configured to determine, after determining first attitude information of the target aircraft in the target simulation image as second attitude information of the target aircraft at the first time, a measured image of the plurality of measured optical images at a second time as a target measured optical image, and determine the second time as a target time, where a time of the target observation arc segment includes the second time, and the second time is a next time of the first time; the second determination unit 30 is further configured to determine the first attitude information of the target aircraft in the target simulation image as the second attitude information of the target aircraft at the second time.

The device obtains a plurality of simulated optical images and a target measured optical image of a target aircraft at a target moment through an obtaining unit 10, determines the simulated optical image with the maximum similarity with the target measured optical image in the plurality of simulated optical images as a target simulated image through a first determining unit 20, and determines first attitude information of the target aircraft in the target simulated image as second attitude information of the target aircraft at the target moment through a second determining unit 30, wherein the first attitude information is used for indicating the attitude displayed by the target aircraft in the target simulated image, and the second attitude information is used for indicating the measured attitude of the target aircraft at the target moment. Because the simulated optical image of the aircraft is generated through simulation, the simulated optical image which is closest to the characteristic value of the actually-measured optical image is selected, and the attitude information of the aircraft of the closest simulated optical image is used as the attitude information of the aircraft, the aim of determining the attitude of the aircraft is fulfilled, the problem that the attitude of the aircraft is difficult to estimate through an optical externally-measuring means in an actual space flight test task is solved, and the attitude measurement requirement of the actual space flight task is met.

Example 4

The embodiment of the invention also provides a storage medium. The storage medium has stored therein a computer program, wherein the computer program is arranged to execute the method for determining the attitude of a target aircraft based on an optical image according to an embodiment of the invention when running.

It will be apparent to those skilled in the art that the modules or steps of the present invention described above may be implemented by a general purpose computing device, they may be centralized on a single computing device or distributed across a network of multiple computing devices, and they may alternatively be implemented by program code executable by a computing device, such that they may be stored in a storage device and executed by a computing device, or fabricated separately as individual integrated circuit modules, or fabricated as a single integrated circuit module from multiple modules or steps. Thus, the present invention is not limited to any specific combination of hardware and software.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for determining the attitude of a target aircraft based on an optical image is characterized by comprising the following steps:

acquiring a plurality of simulated optical images and a target actual measurement optical image of a target aircraft at a target moment;

determining the simulation optical image with the maximum similarity with the target actual measurement optical image in the plurality of simulation optical images as a target simulation image;

determining first attitude information of the target aircraft in the target simulation image as second attitude information of the target aircraft at the target moment, wherein the first attitude information is used for indicating an attitude displayed by the target aircraft in the target simulation image, and the second attitude information is used for indicating a measured attitude of the target aircraft at the target moment;

wherein, prior to acquiring the plurality of simulated optical images and the one measured target optical image of the target aircraft at the target time, the method further comprises: acquiring a plurality of measured optical images shot in a target observation arc section, wherein the plurality of measured optical images are different in corresponding time; determining an actual measurement optical image with a first moment in the plurality of actual measurement optical images as the target actual measurement optical image, and determining the first moment as the target moment, wherein the time of the target observation arc segment comprises the first moment;

determining the first attitude information of the target aircraft in the target simulation image as the second attitude information of the target aircraft at the target moment comprises: determining the first attitude information of the target aircraft in the target simulation image as the second attitude information of the target aircraft at the first moment, wherein the second attitude information is used for indicating the measured attitude of the target aircraft at the first moment.

2. The method of claim 1, wherein acquiring the plurality of simulated optical images of the target aircraft at the target time comprises:

acquiring ground-based measurement data of the target aircraft at the target moment;

acquiring a motion state parameter of the target aircraft corresponding to the ground-based measurement data;

and generating the plurality of simulated optical images of the target aircraft according to the motion state parameters, wherein the change angle of the attitude angle of the target aircraft in any two adjacent simulated optical images in the plurality of simulated optical images is the target angular velocity.

3. The method of claim 1, wherein determining, as the target simulated image, the simulated optical image with the greatest similarity to the target measured optical image from among the plurality of simulated optical images comprises:

acquiring a first characteristic value of each simulated optical image and a second characteristic value of the target actual measurement optical image;

obtaining the similarity between the first characteristic value and the second characteristic value of each simulated optical image to obtain a plurality of similarities;

and determining the simulated optical image corresponding to the maximum similarity in the multiple similarities as the target simulated image.

4. The method of claim 3, wherein obtaining the first characteristic value for each of the simulated optical images comprises:

and acquiring the first characteristic value of a solar array area and a cabin area of each simulated optical image, wherein the solar array area corresponds to the solar array of the target aircraft, and the cabin area corresponds to the cabin of the target aircraft.

5. The method of claim 4, wherein obtaining the first characteristic values for the solar panel region and the hull region of each of the simulated optical images comprises:

and acquiring characteristic values of each simulated optical image, including the long axis direction angle and the short axis direction angle of the circumscribed rectangle of the solar array area, and the characteristic values of the long axis direction angle and the short axis direction angle of the circumscribed rectangle of the cabin area.

6. The method of claim 3, wherein obtaining the second characteristic value of the measured optical image of the target comprises:

and responding to a target instruction generated by target operation on a solar array area and a cabin area of the target actual measurement optical image to acquire the second characteristic value, wherein the solar array area corresponds to the solar array of the target aircraft, and the cabin area corresponds to the cabin of the target aircraft.

7. The method of claim 6, wherein obtaining the second feature values in response to the target instructions generated by the target operation on the solar panel region and the hull region of the target measured optical image comprises:

on the solar array area and the cabin area of the target measured optical image, in response to the target instruction generated by the target operation, obtaining characteristic values including a long axis direction angle and a short axis direction angle of a circumscribed rectangle of the solar array area and characteristic values including a long axis direction angle and a short axis direction angle of a circumscribed rectangle of the cabin area.

8. The method of claim 3, wherein obtaining a similarity between the first and second eigenvalues for each of the simulated optical images, the obtaining the plurality of similarities comprises:

and obtaining the similarity between the first characteristic value and the second characteristic value of each simulated optical image according to the Euclidean distance between the first characteristic value and the second characteristic value of each simulated optical image, so as to obtain the multiple similarities.

9. The method of claim 8, wherein determining the simulated optical image corresponding to the largest similarity among the plurality of similarities as the target simulated image comprises:

determining the simulated optical image corresponding to the first characteristic value with the minimum Euclidean distance between the second characteristic values as the target simulated image, wherein the similarity of the simulated optical image corresponding to the first characteristic value with the minimum Euclidean distance between the second characteristic values is the maximum similarity in the plurality of similarities.

10. The method of claim 1,

after determining the first pose information of the target aircraft in the target simulation image as the second pose information of the target aircraft at the first time, the method further comprises: determining an actual measurement optical image with the moment as a second moment in the plurality of actual measurement optical images as the target actual measurement optical image, and determining the second moment as the target moment, wherein the time of the target observation arc segment comprises the second moment, and the second moment is the next moment of the first moment;

determining the first attitude information of the target aircraft in the target simulation image as the second attitude information of the target aircraft at the target moment comprises: and determining the first attitude information of the target aircraft in the target simulation image as the second attitude information of the target aircraft at the second moment.

11. An optical image-based target aircraft attitude determination apparatus, comprising:

the acquiring unit is used for acquiring a plurality of simulated optical images and a target actual measurement optical image of the target aircraft at a target moment;

a first determining unit, configured to determine, as a target simulated image, a simulated optical image with a maximum similarity to the target actually-measured optical image in the plurality of simulated optical images;

a second determining unit, configured to determine first attitude information of the target aircraft in the target simulation image as second attitude information of the target aircraft at the target time, where the first attitude information is used to indicate an attitude displayed by the target aircraft in the target simulation image, and the second attitude information is used to indicate an actually-measured attitude of the target aircraft at the target time;

the device is further used for acquiring a plurality of measured optical images shot in a target observation arc section before acquiring the plurality of simulated optical images and the target measured optical image of the target aircraft at the target moment, wherein the plurality of measured optical images correspond to different moments; determining an actual measurement optical image with a first moment in the plurality of actual measurement optical images as the target actual measurement optical image, and determining the first moment as the target moment, wherein the time of the target observation arc segment comprises the first moment;

the second determination unit is further configured to determine the first attitude information of the target aircraft in the target simulation image as the second attitude information of the target aircraft at the target time by: determining the first attitude information of the target aircraft in the target simulation image as the second attitude information of the target aircraft at the first moment, wherein the second attitude information is used for indicating the measured attitude of the target aircraft at the first moment.

12. A storage medium, in which a computer program is stored, wherein the computer program is arranged to perform the method of any of claims 1 to 10 when executed.