A star-inertial integrated dynamic calibration method based on refractive surface constraint mechanism

Abstract

The application discloses a star-inertial integrated outfield dynamic calibration method based on a refracting surface constraint mechanism, and relates to the technical field of calibration methods, and specifically discloses the following technical scheme: a relationship model of an observed star position and a zenith direction is established based on a refracting surface constraint mechanism and observation imaging of a star, a first zenith direction measurement model under a star sensor system corresponding to an observation time and an observation position is established based on the relationship model; a second zenith direction measurement model under an inertial navigation system of the zenith direction of a current observation position is established through a filter combination model based on real-time measurement values of angular velocity and angular acceleration of the inertial navigation system; a zenith direction integrated conversion matrix model between the inertial navigation system and the star sensor system is established by simultaneously solving the first zenith direction measurement model under the star sensor coordinate system and the second zenith direction measurement model under the inertial navigation system; and a star-inertial integrated outfield optimization calibration model is established by changing the longitude and latitude of the observation position and the observation direction for multiple times, so that star-inertial integrated outfield calibration is carried out.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of astronomical autonomous navigation, in particular to a star-inertial integrated field dynamic calibration method and system based on a refraction surface constraint mechanism, which is used to solve the multi-level coupling of current starlight / inertial integrated navigation system calibration and the error influence caused by online calibration, and reduce the error influence through integrated field calibration. BACKGROUND

[0002] As an autonomous navigation system applied in the field of aerospace, astronomical / inertial integrated navigation technology has been a key technology that countries around the world have been constantly researching, exploring and seeking to break through. This technology can solve the problem of obtaining high-precision and stable carrier attitude information in the case of satellite navigation denial or interference.

[0003] Among them, the calibration of the installation matrix between the astronomical observation system and the inertial measurement system is one of the key cores to achieve high-precision navigation information acquisition. Generally, the determination of the installation matrix in the astronomical / inertial integrated navigation system adopts a separate calibration technology. The installation relationship between the inertial navigation system and the carrier and the installation relationship between the star sensor and the carrier are calibrated through optical prisms and the like, and then the installation relationship between the star sensor and the inertial system is obtained by two-stage cascade.

[0004] For example, in the prior art, the Chinese patent application with the publication number CN115060290A "System-level calibration method of star-inertial integrated navigation equipment" uses a three-axis turntable and a star simulator to establish a Kalman filter model with the inertial navigation output information and the star vector measured by the star sensor, to realize one-time calibration of the star sensor installation error and the inertial unit error (scale factor error, installation error, constant error); the Chinese patent application with the publication number CN112729335A "Inertial / starlight integrated navigation system calibration method suitable for a shaking base" installs the inertial unit and the star sensor on the carrier, and the inertial unit outputs the position, velocity and attitude information of the carrier through navigation calculation, and the star sensor outputs the attitude information of the carrier, to realize online calibration of the installation error of the inertial / starlight integrated navigation system under a shaking base; and the Chinese patent application with the publication number CN110672128A "Starlight / inertial integrated navigation and error online calibration method" estimates the platform misalignment angle and the star sensor installation error according to the starlight direction unit vector of three stars in the launch inertial coordinate system, to improve the starlight / inertial integrated navigation precision.

[0005] The above methods all belong to separate measurement methods, and the existing star / inertial integrated navigation theoretical methods have the following problems:

[0006] (1) The calibration of the discrete star / inertial integrated installation matrix takes the carrier as the intermediate node connecting the star sensor observation system and the inertial navigation measurement system. The errors of the star sensor and the inertial measurement system are coupled into the overall integrated navigation system, forming multi-level coupling. The carrier's participation error in each level is coupled into the overall installation matrix, thus affecting the attitude measurement results of the entire integrated navigation system.

[0007] (2) Calibration in a laboratory environment requires large-scale special equipment with high precision and high cost, such as high-precision three-axis turntables and single-star simulators, which are extremely costly.

[0008] (3) There is a lack of effective integrated calibration methods for on-orbit operation scenarios.

[0009] In summary, the calibration of the installation matrix in existing astronomical / inertial integrated navigation systems still suffers from multi-level calibration error coupling, and there is an urgent need to break through the technology of integrated calibration to improve the measurement accuracy of integrated navigation systems. Summary of the Invention

[0010] The purpose of this invention is to provide a dynamic calibration method and system for integrated astronomical and inertial navigation systems based on the refractive surface constraint mechanism. This overcomes the problem of multi-level calibration error coupling in the calibration of the installation matrix of existing astronomical / inertial combined autonomous navigation technologies. The provided method and system establishes an integrated transformation relationship model of the zenith direction based on the starlight refractive surface constraint mechanism. It can achieve high-precision integrated calibration of the installation matrix between astronomical and inertial measurement systems under real-time observation conditions in the field and in-orbit scenarios, thus realizing the integrated calibration of the installation matrix of the integrated astronomical / inertial navigation system.

[0011] The first aspect of this invention is to provide a star-inertial integrated external field calibration method based on the refractive surface constraint mechanism, comprising:

[0012] S1. Based on the refracting surface constraint mechanism and the observation and imaging of stars, a relationship model between the observed star position and the zenith direction is established. Based on the relationship model, a first zenith direction measurement model is established under the star sensor system corresponding to the observation time and observation position.

[0013] S2, based on the real-time measurements of angular velocity and angular acceleration of the inertial navigation system, a second zenith direction measurement model of the current observation position under the inertial navigation system is established through a filtered combination model; wherein, the inertial navigation system includes a gyroscope and an accelerometer;

[0014] S3, by combining the first zenith direction measurement model under the star sensor coordinate system and the second zenith direction measurement model under the inertial navigation system, a unified zenith direction transformation matrix model between the inertial navigation system and the star sensor system is established.

[0015] S4. Based on the zenith direction integrated transformation matrix model, the star-inertial integrated field field optimization calibration model is established by changing the latitude and longitude of the observation position and the observation direction multiple times, and the star-inertial integrated field field calibration is performed based on the star-inertial integrated field field optimization calibration model.

[0016] Preferably, S1 includes:

[0017] S11, based on the star sensor, performs exposure integration imaging of the starry sky within the field of view under the first weather conditions to obtain a star image star map;

[0018] S12, Based on the centroid positioning of the star target in the star imaging star map, the observed star vector in the star sensor coordinate system is calculated;

[0019] S13, Based on the observed star vectors and their matching with the reference angular distance library and the pyramid star chart identification, the correspondence between the observed stars and the stars in the reference star catalog is obtained;

[0020] S14. Based on the refraction surface constraint mechanism, a first refraction surface constraint relationship model is established between the observed star and the zenith vector in the observation coordinate system.

[0021] S15. Based on the reference star obtained by star map recognition, establish a second refraction surface constraint relationship model in the reference coordinate system.

[0022] S16. An optimal solution model is established based on the first and second refractive surface constraint relationships for all stars. The optimal solution model is the first zenith direction measurement model of the star sensor system corresponding to the observation time and observation position.

[0023] Preferably, step S14 includes: in the star sensor imaging coordinate system, based on the starlight refraction surface constraint mechanism, the angle between the refraction surfaces of two stars... As shown in equation (3):

[0024]

[0025] In equation (3), and These are the starlight refraction surfaces corresponding to stars i and j, respectively. The zenith direction in the star sensor imaging coordinate system;

[0026] S15 includes:

[0027] In the navigation coordinate system, based on the starlight refraction surface constraint mechanism, the angle between the refraction surfaces of two stars... As shown in equation (4):

[0028]

[0029] where θ S,i (t,φ,λ) and θ S,j (t,φ,λ) are the azimuth angles of the observed stars i and j in the N system before entering the atmosphere, obtained by IAU SOFA conversion from the observation time t and the observation position latitude and longitude (φ,λ) respectively;

[0030] The S16 comprises:

[0031] Based on the formula (3) and (4), the zenith direction loss function relationship model in the star sensor observation system is constructed as shown in the formula (5):

[0032]

[0033] In a frame of star map, there are a large number of observable stars N, which are combined with each other and based on the zenith direction loss function relationship model to establish an optimization solving model of the zenith direction, i.e. shown in the formula (6):

[0034]

[0035] In the formula (6), i and j are stars constituting the minimum unit of starlight atmospheric refraction surface, less than

[0036] Preferably, the S2 comprises:

[0037] S21, the angular velocity and angular acceleration of the current carrier observation time are measured by the inertial navigation system in real time to obtain real-time state information;

[0038] S22, a filter combination model for four-element attitude estimation of the inertial navigation system is established, the filter combination model is a Kalman filter combination model, containing six degrees of freedom of angular velocity and angular acceleration;

[0039] S23, based on the four-element attitude estimation result of the inertial navigation system, a second zenith direction measurement model of the zenith direction of the current observation position in the inertial navigation measurement system is established.

[0040] Preferably, the S21 comprises:

[0041] Based on the inertial navigation system composed of gyroscopes and accelerometers, the sampling period is T, the three-axis angular velocity (ω x ω y ω z ) and three-axis angular acceleration (α x α y α z ) of the current time are measured;

[0042] Based on the coordinate system conversion, the three-axis angular velocity of the gyroscope and the three-axis attitude Euler angle are expressed as formula (7):

[0043]

[0044] In formula (7), (r p y) respectively represent the pitch angle, roll angle and heading angle, is the attitude update angular velocity;

[0045] For the acceleration, the pitch and roll angles can be expressed as formula (8):

[0046]

[0047] The S22 comprises:

[0048] Filtering optimization solution of dynamic pitch and heading angle of the inertial navigation system by Kalman filtering is shown as formula (9):

[0049]

[0050] In formula (9), f() is the Kalman filtering method;

[0051] The S23 comprises:

[0052] In the inertial navigation system coordinate system, the zenith direction

[001] is expressed as:

[0053]

[0054] In formula (10), is the conversion matrix from the inertial navigation coordinate system to the horizontal coordinate system, which is determined by the pitch angle and the heading angle .

[0055] Preferably, the S3 comprises: establishing an integrated conversion relationship model of the zenith direction from the star sensor measurement coordinate system to the inertial navigation system measurement coordinate system, as shown in formula (11):

[0056]

[0057] In formula (11), is the installation matrix between the star sensor and the inertial navigation system, that is, the parameter to be calibrated.

[0058] Preferably, the S4 comprises:

[0059] S41, changing the installation angle and the observation position of the integrated navigation system to obtain the integrated conversion matrix relationship information of the zenith direction under different observation directions and observation positions of latitude and longitude; the integrated navigation system is composed of the star sensor system and the inertial navigation system.​

[0060] S42, based on the zenith direction integrated conversion matrix relationship information and the mass field real-time observation data set, a star-inertial integrated field optimization calibration model is established based on the least square method;

[0061] S43, based on the star-inertial integrated field optimization calibration model, the installation matrix between the star sensor and the inertial navigation system in the integrated navigation system is measured, and the measurement formula of the installation matrix is as shown in formula (12):

[0062]

[0063] In the formula, M is the mass field real-time observation data set And The number of stars.

[0064] The second aspect of the application is to provide a star-inertial integrated field calibration system based on the refraction surface constraint mechanism, comprising:

[0065] A first zenith direction measurement model establishment module is used to establish a relationship model between the observed star position and the zenith direction based on the refraction surface constraint mechanism and the observation imaging of the star, and a first zenith direction measurement model of the star sensor system corresponding to the observation time and the observation position is established based on the relationship model;

[0066] A second zenith direction measurement model establishment module is used to establish a second zenith direction measurement model of the zenith direction of the current observation position in the inertial navigation system based on the real-time measurement value of the angular velocity and the angular acceleration of the inertial navigation system through a filtering combination model; wherein the inertial navigation system comprises a gyroscope and an accelerometer;

[0067] A conversion matrix model establishment module is used to establish a zenith direction integrated conversion matrix model between the inertial navigation system and the star sensor system based on the first zenith direction measurement model and the second zenith direction measurement model;

[0068] A star-inertial integrated field calibration module is used to establish a star-inertial integrated field optimization calibration model by changing the observation latitude and longitude and the observation direction multiple times based on the zenith direction integrated conversion matrix model, and to perform star-inertial integrated field calibration based on the star-inertial integrated field optimization calibration model.

[0069] The third aspect of the application provides an electronic device comprising a processor and a memory, wherein the memory stores a plurality of instructions, and the processor is used to read the instructions and execute the method according to the first aspect.

[0070] The fourth aspect of the present application provides a computer readable storage medium, the computer readable storage medium stores a plurality of instructions, the plurality of instructions can be read and executed by the processor to execute the method of the first aspect.

[0071] The method, system, electronic device and readable storage medium of the present application have the following beneficial effects:

[0072] (1) By constructing a zenith direction integrated conversion relationship measurement model based on the starlight refraction plane constraint mechanism, an integrated calibration of the star / inertial combined navigation system installation matrix is realized by establishing an integrated conversion relationship measurement model between the star sensor observation system and the inertial navigation measurement system.

[0073] (2) The star / inertial combined navigation system installation matrix can be calibrated in the field and on-orbit scenarios without the need to build an indoor expensive experimental environment. BRIEF DESCRIPTION OF DRAWINGS

[0074] In order to more clearly illustrate the technical solutions in the specific embodiments or related art, the following will briefly introduce the drawings needed to be used in the specific embodiments or related art description. Obviously, the drawings described below are some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0075] Figure 1 The star / inertial integrated field calibration method flowchart based on the refraction plane constraint mechanism is provided for the embodiments of the present application.

[0076] Figure 2 The electronic device structure diagram is provided for the embodiments of the present application. DETAILED DESCRIPTION

[0077] The technical solutions of the present application will be described in detail below with reference to the drawings. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0078] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore it cannot be understood as a limitation of the present application. In addition, the terms "first", "second", "third" are only for the purpose of description, and cannot be understood as indicating or implying relative importance.

[0079] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0080] This embodiment is based on the refractive surface constraint mechanism: assuming that the refraction and dispersion of starlight in the atmosphere only changes its zenith direction angle and not its azimuth angle, then the position of the refractive surface before and after the starlight passes through the atmosphere does not change, that is, "the refractive surface remains unchanged"; at the same time, the atmospheric refractive surfaces of stars at the same observation time intersect at the observation zenith direction, that is, "the refractive surfaces are collinear".

[0081] Example 1

[0082] like Figure 1 As shown, this embodiment provides a star-inertial integrated external field calibration method based on the refractive surface constraint mechanism, including:

[0083] S1. Based on the refracting surface constraint mechanism and the observation and imaging of stars, a relationship model between the observed star position and the zenith direction is established. Based on the relationship model, a first zenith direction measurement model is established under the star sensor system corresponding to the observation time and observation position.

[0084] S2, based on the real-time measurements of angular velocity and angular acceleration of the inertial navigation system, a second zenith direction measurement model of the current observation position under the inertial navigation system is established through a filtered combination model; wherein, the inertial navigation system includes a gyroscope and an accelerometer;

[0085] S3, by combining the first zenith direction measurement model under the star sensor coordinate system and the second zenith direction measurement model under the inertial navigation system, a unified zenith direction transformation matrix model between the inertial navigation system and the star sensor system is established.

[0086] S4. Based on the zenith direction integrated transformation matrix model, the star-inertial integrated field field optimization calibration model is established by changing the latitude and longitude of the observation position and the observation direction multiple times, and the star-inertial integrated field field calibration is performed based on the star-inertial integrated field field optimization calibration model.

[0087] In a preferred embodiment, S1 includes:

[0088] S11 uses a star sensor to perform exposure integration imaging of stars under clear night weather to obtain an imaged star map;

[0089] In this embodiment, in a clear night observation environment, the star sensor obtains a star imaging star map by exposure integration imaging of the star field in the field of view.

[0090] S12, based on the centroid positioning of the star target in the imaging star map, an observation star vector in the star sensor coordinate system is calculated;

[0091] In this embodiment, the centroid positioning method is used to detect the star target in the star map, and an observation star vector in the star sensor coordinate system is obtained As shown in formula (1):

[0092]

[0093] In formula (1), (x0, y0) is the principal point of the star sensor, f is the focal length of the star sensor, (x s ,y s ) is the centroid coordinates of the star in the star map;

[0094] S13, based on the observation star vector and the matching with the reference angular distance library, the corresponding relationship between the observation star and the star in the reference star table is obtained;

[0095] In this embodiment, based on the pyramid star map recognition method, the observation star is matched and recognized all over the sky based on the reference angular distance library, and the corresponding relationship between the observation star and the star in the reference star table is obtained as shown in formula (2):

[0096]

[0097] In formula (2), is the conversion matrix from the star sensor coordinate system S to the navigation coordinate system N, and the reference star table is the reference vector converted to the N system through the observation time and the observation position;

[0098] S14, based on the refraction surface constraint mechanism, a first refraction surface constraint relationship model between the observation star and the zenith vector in the observation coordinate system is established;

[0099] In this embodiment, in the star sensor imaging coordinate system, based on the starlight refraction surface constraint mechanism, the included angle between the refraction surfaces of two stars is shown in formula (3):

[0100]

[0101] In formula (3), and are the starlight refraction surfaces corresponding to the stars i and j respectively, is the zenith direction in the star sensor imaging coordinate system;​

[0102] S15, based on the star map recognition obtained reference star, the establishment of the second reference coordinate system under the refraction surface constraint relationship model;

[0103] In this embodiment, in the navigation coordinate system, based on the starlight refraction surface constraint mechanism, the angle between the refraction surfaces of the two stars Again for formula (4) is shown:

[0104]

[0105] Where, θ S,i (t,φ,λ) and θ S,j (t,φ,λ) are the azimuth angles of the observed stars i and j before entering the atmosphere in the N system, which are obtained by IAU SOFA conversion from the observation time t and the observation position longitude and latitude (φ,λ)

[0106] S16, based on the first refraction surface constraint relationship and the second refraction surface constraint relationship model corresponding to all star pairs, an optimization solving model is established, wherein the optimization solving model is a first zenith direction measurement model under the star sensor system corresponding to the observation time and the observation position;

[0107] In this embodiment, based on formula (3) and (4), the zenith direction loss function relationship model in the star sensor observation system is constructed as shown in formula (5):

[0108]

[0109] In a frame of star map, there are a large number of observable stars N, which are combined with each other and based on the zenith direction loss function relationship model to establish an optimization solving model of the zenith direction, that is, formula (6) is shown:

[0110]

[0111] In formula (6), i and j are the stars that constitute the smallest unit of starlight atmospheric refraction surface, which are less than

[0112] As a preferred embodiment, the S2 comprises:

[0113] S21, the inertial navigation system measures the angular velocity and angular acceleration of the current carrier observation time in real time to obtain real-time state information;

[0114] In this embodiment, based on the inertial navigation system composed of gyroscopes and accelerometers, the sampling period is T, and the three-axis angular velocity (ω x ω y ω z ) and three-axis angular acceleration (α x αy α z );

[0115] Based on the coordinate system conversion, the three-axis angular velocity of the gyroscope and the three-axis attitude Euler angle are expressed as formula (7):

[0116]

[0117] In formula (7), (r p y) respectively represent the pitch angle, roll angle and heading angle, is the attitude update angular velocity.

[0118] For the acceleration, the pitch and roll angles can be expressed as formula (8):

[0119]

[0120] S22, a filter combination model for four-element attitude estimation of the inertial navigation system is established, the filter combination model is a Kalman filter combination model, and contains six degrees of freedom of angular velocity and angular acceleration;

[0121] In this embodiment, the dynamic pitch and heading angles of the inertial navigation system are filtered and optimized by Kalman filtering to be shown in formula (9):

[0122]

[0123] In formula (9), f( ) is a Kalman filtering method.

[0124] S23, based on the four-element attitude estimation result of the inertial navigation system, a second zenith direction measurement model of the zenith direction at the current observation position in the inertial navigation measurement system is established.

[0125] In this embodiment, under the inertial navigation system coordinate system, the zenith direction

[001] can be expressed as:

[0126]

[0127] In formula (10), is the conversion matrix from the inertial navigation coordinate system to the horizontal coordinate system, which is determined by the pitch angle and the heading angle .

[0128] As a preferred embodiment, the S3 comprises: based on the first zenith direction measurement model and the second zenith direction measurement model, an integrated conversion matrix model of the zenith direction between the inertial navigation system measurement coordinate system and the star sensor measurement coordinate system is established.

[0129] ​An integrated conversion relationship model of zenith direction is established from the star sensor measurement coordinate system to the inertial navigation system measurement coordinate system, as shown in equation (11):

[0130]

[0131] In equation (11), is the installation matrix between the star sensor and the inertial navigation system, i.e., a parameter to be calibrated.

[0132] As a preferred embodiment, the S4 comprises:

[0133] S41, the installation angle and the observation position of the integrated navigation system are changed to obtain the integrated conversion matrix relationship information of the zenith direction under different observation directions and observation positions and latitudes and longitudes; the integrated navigation system is composed of the star sensor system and the inertial navigation system;

[0134] S42, based on the integrated conversion matrix relationship information of the zenith direction and a mass of real-time observation data sets in the field, an integrated star-inertial field optimization calibration model is established;

[0135] In this embodiment, in the static state, and do not change. In order to solve , the placement angle of the integrated navigation system needs to be changed or the observation position of the integrated navigation system needs to be changed, so that and change, and a mass of real-time observation data sets in the field and

[0136] On this basis, an integrated star-inertial field optimization calibration model is established based on the least square method.

[0137] S43, the installation matrix between the star sensor and the inertial navigation system in the integrated navigation system is measured based on the integrated star-inertial field optimization calibration model.

[0138] In this embodiment, the measurement formula of the installation matrix between the star sensor and the inertial navigation system in the integrated navigation system is shown in equation (12):

[0139]

[0140] In the formula, M is the number of test data sets and .

[0141] Embodiment two

[0142] The embodiment provides an integrated star-inertial field calibration system based on a refractive surface constraint mechanism, comprising:

[0143] The first zenith direction measurement model establishing module is configured to establish a relationship model between the observed star position and the zenith direction based on the refraction surface constraint mechanism and the observation imaging of the star, and establish a first zenith direction measurement model of the star sensor system corresponding to the observation time and the observation position based on the relationship model.

[0144] The second zenith direction measurement model establishing module is configured to establish a second zenith direction measurement model of the zenith direction of the current observation position in the inertial navigation system based on the real-time measurement values of the angular velocity and the angular acceleration of the inertial navigation system through a filter combination model, wherein the inertial navigation system comprises a gyroscope and an accelerometer.

[0145] The conversion matrix model establishing module is configured to establish a zenith direction integration conversion matrix model between the inertial navigation system and the star sensor system based on the first zenith direction measurement model in the star sensor coordinate system and the second zenith direction measurement model in the inertial navigation system.

[0146] The star-inertial integration field calibration module is configured to establish a star-inertial integration field optimization calibration model by changing the observation position latitude and longitude and the observation direction multiple times based on the zenith direction integration conversion matrix model, and perform star-inertial integration field calibration based on the star-inertial integration field optimization calibration model.

[0147] The application further provides a memory storing a plurality of instructions for implementing the method of the first embodiment.

[0148] As shown in the accompanying drawings, Figure 2 The application further provides an electronic device comprising a processor 301 and a memory 302 connected to the processor 301, wherein the memory 302 stores a plurality of instructions, and the instructions can be loaded and executed by the processor to enable the processor to perform the method of the first embodiment.

[0149] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the application, and not to limit them; although the application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement to part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the application.

Claims

1. A star-inertial integrated field calibration method based on a refractive surface constraint mechanism, characterized in that, The method comprises the following steps: S1, a relationship model between the observed star position and the zenith direction is established based on the refraction surface constraint mechanism and the observation imaging of the star, and a first zenith direction measurement model corresponding to the observation time and the observation position under the star sensor system is established based on the relationship model; S2, a second zenith direction measurement model of the zenith direction of the current observation position under the inertial navigation system is established by filtering and combining the model based on the real-time measurement values of the angular velocity and the angular acceleration of the inertial navigation system; wherein the inertial navigation system comprises a gyroscope and an accelerometer; S3, a zenith direction integrated conversion matrix model between the inertial navigation system and the star sensor system is established by simultaneously establishing the first zenith direction measurement model under the star sensor coordinate system and the second zenith direction measurement model under the inertial navigation system; S4, based on the zenith direction integrated conversion matrix model, an integrated star-inertial optimization calibration model is established by changing the observation position latitude and longitude and the observation direction multiple times, and the integrated star-inertial field calibration is performed based on the integrated star-inertial optimization calibration model; The S1 comprises: S11, the starry sky in the field of view under the first weather condition is exposed and integrated to be imaged based on the star sensor, and a star imaging star map is obtained; S12, the centroid positioning of the star target in the star imaging star map is performed, and the observed star vector under the star sensor coordinate system is calculated; S13, the corresponding relationship between the observed star and the star in the reference star table is obtained based on the observed star vector, the matching with the reference angular distance library and the pyramid star map identification; S14, a first refraction surface constraint relationship model between the observed star and the zenith vector under the observation coordinate system is established based on the refraction surface constraint mechanism; S15, a second refraction surface constraint relationship model under the reference coordinate system is established based on the reference star obtained by the star map identification; S16, an optimization solving model is established based on the first refraction surface constraint relationship and the second refraction surface constraint relationship corresponding to all stars, wherein the optimization solving model is the first zenith direction measurement model corresponding to the observation time and the observation position under the star sensor system; Wherein, the S14 comprises: in the star sensor imaging coordinate system, the included angle between the refraction surfaces of two stars is calculated based on the starlight refraction surface constraint mechanism; The S15 comprises: in the navigation coordinate system, the included angle between the refraction surfaces of two stars is calculated based on the starlight refraction surface constraint mechanism; The S16 comprises: a zenith direction loss function relationship model in the star sensor observation system is constructed; there are a large number of observable stars N in a frame of star map, which are combined with each other and based on the zenith direction loss function relationship model to establish an optimization solving model of the zenith direction; The S3 comprises: an integrated conversion relationship model of the zenith direction is established from the star sensor measurement coordinate system to the inertial navigation system measurement coordinate system; The S4 comprises: S41, the installation angle and the observation position of the integrated navigation system are changed to obtain the integrated conversion matrix relationship information of the zenith direction under different observation directions and observation position latitudes and longitudes; the integrated navigation system is composed of the star sensor system and the inertial navigation system; S42, based on the zenith direction integrated conversion matrix relationship information and the mass field real-time observation data set, based on the least square method to establish the star-inertial integrated field optimization calibration model; S43, based on the star-inertial integrated field optimization calibration model, the installation matrix between the star sensor and the inertial navigation system in the integrated navigation system is measured.

2. The star-inertial integrated field calibration method based on the refractive surface constraint mechanism according to claim 1, characterized in that, The angle between the refraction planes of the two stars is calculated based on the starlight refraction plane constraint mechanism in the star sensor imaging coordinate system, and the angle between the refraction planes of the two stars is calculated as follows: two stars is shown in formula (3): （3）； In formula (3), and are respectively a star and corresponding starlight refraction surface, is the zenith direction in the imaging coordinate system of the star sensor. The angle between the refraction surfaces of the two stars is calculated based on a starlight refraction surface constraint mechanism in a navigation coordinate system is shown in formula (4): （4）； where with are the observed stars with azimuth in the N system before entering the atmosphere, time of observation and the observed position latitude and longitude obtained via IAU SOFA conversion; The S16 comprises: Based on formula (3) and (4), the zenith direction loss function relationship model in the star sensor observation system is constructed as shown in formula (5): （5）； wherein, is a zenith direction vector in the star sensor imaging coordinate system, is a zenith direction vector in the star sensor imaging coordinate system, is an observed star vector of the i-th star in the star sensor coordinate system, calculated by star map centroid positioning, is an observed star vector of the i-th star in the star sensor coordinate system, calculated by star map centroid positioning, is an observed star vector of the i-th star in the star sensor coordinate system, calculated by star map centroid positioning; is an inverse cosine function used to calculate the included angle between two vectors. There are a large number of observable stars N in a frame of star map, which are combined with each other and based on the zenith direction loss function relationship model to establish the optimization solving model of the zenith direction, that is, formula (6) is shown: （6）； In formula (6), i and j are stars that constitute the minimum unit of the starlight atmospheric refraction surface, and i < j. .

3. The star-inertial integrated field calibration method based on the refractive surface constraint mechanism according to claim 2, characterized in that, The S2 comprises: S21, the angular velocity and angular acceleration of the current carrier observation time are measured by the inertial navigation system to obtain real-time state information; S22, a filter combination model for four-element attitude estimation of the inertial navigation system is established, the filter combination model is a Kalman filter combination model, and contains six degrees of freedom of angular velocity and angular acceleration; S23, based on the four-element attitude estimation result of the inertial navigation system, a second zenith direction measurement model of the zenith direction at the current observation position under the inertial navigation measurement system is established.

4. The star-inertial integrated field calibration method based on the refractive surface constraint mechanism according to claim 3, characterized in that, The S21 comprises: Based on the inertial navigation system composed of gyroscopes and accelerometers, the sampling period is T, and the three-axis angular velocity at the current time is measured and three-axis angular acceleration ; Based on coordinate system conversion, the three-axis angular velocity of the gyroscope and the three-axis attitude Euler angle are represented as formula (7): （7）； In formula (7), , and are Euler angles of the triaxial attitude of the carrier, representing the pitch angle , the roll angle and the heading angle , respectively, which are also attitude parameters corresponding to the attitude update angular velocity; , and are the attitude update angular velocity; For acceleration, the pitch and roll angles can be represented as formula (8): （8）； is the acceleration of objects near the surface of the earth due to the earth's gravity; The S22 comprises: Dynamic pitch and heading angle of inertial navigation system using Kalman filter The filter optimization solution is shown in equation (9): （9）； In formula (9), is a Kalman filter method; The S23 comprises: In the inertial navigation system coordinate system, the zenith direction vector in the inertial navigation system coordinate system is represented as: （10）； In formula (10), is the conversion matrix from the inertial navigation coordinate system to the horizontal coordinate system, and is determined by the pitch angle and the heading angle . is the zenith direction vector in the inertial navigation system coordinate system.

5. The star-inertial integrated field calibration method based on the refracting surface constraint mechanism according to claim 4, characterized in that, The integrated conversion relationship model of the zenith direction from the star sensor measurement coordinate system to the inertial navigation system measurement coordinate system is shown as formula (11): （11）； In formula (11), is the installation matrix between the star sensor and the inertial navigation system, i.e., the parameter to be calibrated.

6. The star-inertial integrated field calibration method based on the refracting surface constraint mechanism according to claim 5, characterized in that, The measurement formula of the installation matrix of the S43 is shown as formula (12): （12）； In the formula, For a mass of field real-time observation data sets With The number of 7. A star-inertial integrated field calibration system based on the refractive surface constraint mechanism, for implementing the method of any one of claims 1-6, characterized in that, Comprise: The first zenith direction measurement model establishment module is used for establishing the relationship model of the observed star position and the zenith direction based on the refraction surface constraint mechanism and the observation imaging of the stars, and establishing the first zenith direction measurement model of the star sensor system corresponding to the observation time and the observation position based on the relationship model; The second zenith direction measurement model establishment module is used for establishing the second zenith direction measurement model of the zenith direction at the current observation position under the inertial navigation system based on the real-time measurement value of the angular velocity and angular acceleration of the inertial navigation system through the filter combination model; wherein the inertial navigation system comprises a gyroscope and an accelerometer; The conversion matrix model establishment module is used for establishing the zenith direction integrated conversion matrix model between the inertial navigation system and the star sensor system based on the first zenith direction measurement model under the star sensor coordinate system and the second zenith direction measurement model under the inertial navigation system; The star-inertial integrated field calibration module is used for establishing the star-inertial integrated field optimization calibration model by changing the observation position latitude and longitude and the observation direction multiple times based on the zenith direction integrated conversion matrix model, and calibrating the star-inertial integrated field based on the star-inertial integrated field optimization calibration model.

8. An electronic device, comprising: A computer readable storage medium storing a plurality of instructions readable and executable by a processor to perform the method of any one of claims 1-6.

9. A computer-readable storage medium, characterized in that, A computer readable storage medium storing a plurality of instructions readable and executable by a processor to perform the method of any one of claims 1-6.

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