Star map recognition method, apparatus and related equipment based on improved K-vector

Abstract

This invention discloses a star map recognition method, apparatus, and related equipment based on an improved K-vector. The method includes calculating the elevation angle of the current observation position relative to each star in the star catalog, filtering the stars in the catalog based on the elevation angle to establish a temporary navigation star database; taking any two stars within a preset angular distance range in the temporary navigation star database as a pair, calculating the angular distance of each pair, and constructing an angular distance table based on the cosine value of the calculated angular distance; dividing the angular distance table into equal regions, connecting the beginning and end of each region with straight lines to obtain multiple segmented straight lines; constructing a K-vector lookup table; obtaining the target angular distance between the target navigation star pairs to be identified, and calculating the matching range of the target navigation star pairs in the angular distance table based on the target angular distance, a preset measurement error, and the K-vector lookup table. This method effectively improves the star map recognition speed.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of star map recognition technology, and in particular to star map recognition methods, devices and related equipment based on improved K-vectors. Background Technology

[0002] A star sensor is an autonomous, high-precision astronomical navigation device widely used in aerospace and maritime fields to provide attitude or position information for a vehicle. This process first requires star image recognition, which identifies stars in the sky based on the relative positions of stars in the image, thus enabling subsequent attitude or position calculations. For small-field-of-view star sensors, due to their large reference star library and small inter-star angular distances, directly performing autonomous all-sky star image recognition is quite challenging and time-consuming.

[0003] Traditional K-vector lookup can improve the slow speed of finding angular distances in triangular star map recognition. However, in a large field of view, the constructed straight line cannot accurately map the star pair angular distance table, resulting in uneven distribution of star pair angular distances in different regions of the constructed straight line. That is, some intervals on the constructed straight line include a large number of star pair angular distances, while other intervals do not. This limits the fast lookup performance of K-vector and restricts the lookup speed. Summary of the Invention

[0004] The present invention provides a star map recognition method, apparatus and related equipment, which aims to solve the problem of poor recognition effect when using the traditional K-vector search method for star map recognition in the prior art.

[0005] In a first aspect, embodiments of the present invention provide a star map recognition method based on an improved K-vector, comprising:

[0006] Calculate the elevation angle of the current observation position relative to each star in the star catalog, and filter the stars in the star catalog according to the elevation angle to establish a temporary navigation star library.

[0007] Two stars in the temporary navigation star pool that fall within the preset angular distance range are taken as a pair of stars. The angular distance of each pair of stars is calculated, and the angular distance cosine value of the corresponding pair of stars is calculated based on the angular distance. An angular distance table is constructed using the angular distance cosine value.

[0008] The angular distance table is divided into equal regions, and the beginning and end of the corresponding serial numbers of each region are connected by straight lines to obtain the segmented straight lines corresponding to each region.

[0009] Based on all piecewise straight lines, K-vectors are constructed for each region to obtain a K-vector lookup table;

[0010] Obtain the target angular distance between the target navigation satellite pairs to be identified, and calculate the matching range of the target navigation satellite pairs in the angular distance table based on the target angular distance, the preset measurement error and the K vector lookup table;

[0011] Based on the triangle star map matching algorithm and the matching range, the target navigation star pair is identified to obtain the final identification result.

[0012] Secondly, embodiments of the present invention provide a star map recognition device based on an improved K-vector, comprising:

[0013] The temporary star library construction module is used to calculate the elevation angle of the current observation position relative to each star in the star catalog, and to filter the stars in the star catalog according to the elevation angle, so as to establish a temporary navigation star library with the selected stars;

[0014] An angular distance table construction module is used to take two stars in the temporary navigation star library that belong to a preset angular distance range as a pair of stars, calculate the angular distance of each pair of stars, calculate the angular distance cosine value of the corresponding pair of stars based on the angular distance, and construct an angular distance table based on the angular distance cosine value.

[0015] The region division module is used to divide the angular distance table into equal regions and connect the beginning and end of the corresponding serial numbers of each region with straight lines to obtain the segmented straight lines corresponding to each region.

[0016] The K-vector construction module is used to construct K-vectors for each region based on all piecewise straight lines, and obtain a K-vector lookup table.

[0017] The matching range calculation module is used to obtain the target angular distance between the target navigation star pairs to be identified, and calculate the matching range of the target navigation star pairs in the angular distance table based on the target angular distance, the preset measurement error and the K vector lookup table;

[0018] The identification module is used to identify the target navigation star pair based on the triangle star map matching algorithm and the matching range, and obtain the final identification result.

[0019] Thirdly, embodiments of the present invention provide a computer device, which includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the star map recognition method based on the improved K-vector described in the first aspect.

[0020] Fourthly, embodiments of the present invention also provide a computer-readable storage medium storing a computer program that, when executed by a processor, causes the processor to perform the star map recognition method based on the improved K-vector described in the first aspect.

[0021] This invention provides a star map recognition method, apparatus, and related equipment based on an improved K-vector. The method includes: calculating the elevation angle of the current observation position relative to each star in the star catalog; filtering the stars in the catalog based on the elevation angle to establish a temporary navigation star database; grouping two stars within a preset angular distance range in the temporary navigation star database as a pair; calculating the angular distance of each pair; calculating the cosine value of the angular distance for the corresponding pair; constructing an angular distance table based on the cosine value; dividing the angular distance table into equal regions; connecting the beginning and end of each region's corresponding sequence number with straight lines to obtain segmented straight lines for each region; constructing a K-vector lookup table for each region based on all segmented straight lines; obtaining the target angular distance between the target navigation star pairs to be identified; and calculating the matching range of the target navigation star pairs in the angular distance table based on the target angular distance, a preset measurement error, and the K-vector lookup table. This application improves upon the traditional K-vector lookup method by fitting multiple piecewise straight lines to the regions of the angular distance table, constructing K-vectors corresponding to the piecewise straight lines. These multiple piecewise straight lines uniformly fit the number of star pairs in the angular distance table, avoiding the problem of the traditional K-vector lookup method fitting the entire angular distance table with a single straight line, which fails to accurately map the table. By mapping star pairs in different regions with multiple piecewise straight lines, the number of mapped pairs is uniform, reducing the amount of data corresponding to the straight lines during K-vector lookup, improving lookup speed, reducing memory usage, and effectively enhancing the star map recognition speed. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a flowchart illustrating an embodiment of the star map recognition method provided by the present invention;

[0024] Figure 2 This is a schematic representation of the angular distance of an embodiment of the star map recognition method provided by the present invention;

[0025] Figure 3 This is a schematic diagram of the matching range of an embodiment of the star map recognition method provided by the present invention;

[0026] Figure 4 This is a schematic block diagram of a star map recognition device provided in an embodiment of the present invention. Detailed Implementation

[0027] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] It should be understood that, when used in this specification and the appended claims, the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0029] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0030] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0031] Please see Figure 1 As shown, Figure 1 This is a flowchart illustrating the improved K-vector-based star map recognition method provided in an embodiment of the present invention. The method includes steps S110 to S160.

[0032] Step S110: Calculate the elevation angle of the current observation position relative to each star in the star catalog, and filter the stars in the star catalog according to the elevation angle to establish a temporary navigation star library with the filtered stars;

[0033] In this embodiment, the star catalog is the HIP catalog, and the field of view used for star chart identification is 14°. The altitude difference method is employed, and within this field of view, only stars with a magnitude of 6.0 or lower are needed to meet positioning requirements. The establishment of a temporary navigation star database is based on an altitude angle selection strategy. Therefore, it is first necessary to calculate the altitude angle of the stars based on the current observation location and local time. This calculation method is based on the transformation of the celestial coordinate system. On Earth, since the right ascension and declination of stars in the navigation star database are represented by coordinates in the celestial coordinate system, while the azimuth and altitude angles of stars observed by the observer are represented by coordinates in the horizontal coordinate system, a specific coordinate system transformation is required.

[0034] Specifically, the elevation angle of the current observation position relative to each star in the star catalog is calculated using the following steps: The sidereal time of each star in the catalog is calculated based on the longitude of the current observation position and the corresponding Greenwich Mean Time; the hour angle of each star in the catalog is calculated based on the sidereal time and the right ascension of the corresponding star; and the elevation angle of each star in the catalog is calculated based on the sine of the elevation angle. Sidereal time, as defined in astronomy and geodesy, is the celestial meridian value. It is a time measurement system based on the Earth's rotation period relative to the stars. The time elapsed between two consecutive transits at the vernal equinox is called a sidereal day, which is equal to 23 hours, 56 minutes, and 4.09 seconds of mean solar time. The moment of transit at the vernal equinox is taken as the starting point of this measurement system, i.e., when the sidereal time is zero, and the vernal equinox hour angle is used for measurement. The hour angle refers to the angle between a celestial body and the local meridian. The sidereal time at the current observation location is the sidereal time when the vernal equinox, the origin of the celestial sphere, passes through the meridian of the current observation location. Greenwich Mean Time (GMT) is defined as the sidereal time when the vernal equinox passes through the Greenwich Meridian. Therefore, the sidereal time at the current observation location can be obtained by adding the Greenwich Mean Time to the longitude. Thus, sidereal time is expressed as:

[0035] LST = GST + Longitude;

[0036] Where LST represents the sidereal time at the current observation location, Longitude represents the longitude at the current observation location, and GST represents Greenwich Sidereal Time, all in hours (h). GST is a time standard calculated based on the average rotation period of celestial bodies with Greenwich Observatory as the reference point, and can be obtained by looking up a table.

[0037] Next, the star's hour angle LHA is calculated. The hour angle LHA refers to the hour angle of a star on the meridian at the observer's location. The star's hour angle LHA can be expressed as:

[0038] LHA = LST-Ra;

[0039] Where LHA represents the hour angle of a star, LST represents the sidereal hour, and Ra represents the longitude coordinates of a star on the celestial sphere, i.e., right ascension, all in hours (h). The right ascension of a star can be obtained by looking up a navigation star catalog.

[0040] Finally, using the spherical triangle of the celestial body, the sine value of the altitude angle h of the celestial body can be expressed as:

[0041]

[0042] In the formula, Lat represents the latitude of the current observation position, and Dec represents the declination of the star, in radians. Therefore, the altitude angle of the star can be calculated based on its right ascension and declination, the current observation time, and the current observation position.

[0043] Furthermore, a temporary navigation star database is established by filtering stars based on their elevation angles. Since only stars with a magnitude of 6.0 or lower are needed, stars with a magnitude higher than 6.0 are first removed; after this, the HIP star catalog contains 5044 stars. Before each experiment, the elevation angles of these remaining 5044 stars need to be calculated based on the current time and observation location. Because the elevation difference method typically captures stars with an elevation angle of around 60°, and stars with elevation angles below 30° have poor positioning accuracy and are easily obscured, thus having a relatively small impact on the overall elevation difference method positioning, stars below 30° are further filtered out based on their elevation angles, further reducing the number of stars in the established temporary navigation star database. In addition, if star chart identification needs to be performed over a specific time period, the database can be built multiple times at minute intervals throughout the time period. The union of the stars in these databases yields the temporary navigation star database filtered based on elevation angles for that time period, further reducing the number of stars used for star chart identification.

[0044] Step S120: Take two stars in the temporary navigation star database that belong to the preset angular distance range as a pair of stars, calculate the angular distance of each pair of stars, and calculate the angular distance cosine value of the corresponding pair of stars based on the angular distance, and construct an angular distance table based on the angular distance cosine value.

[0045] In this embodiment, after establishing the temporary navigation star database, an improved K-vector lookup method can be used to construct a corresponding lookup table, accelerating the angular distance lookup speed. The improved K-vector lookup method requires fitting piecewise straight lines to the traditional K-vector. First, two stars within a preset angular distance range in the temporary navigation star database are grouped as a pair, and the angular distance between each pair is calculated. Then, based on the angular distance of each pair, the corresponding angular distance cosine value is calculated. All star pairs are sorted according to their angular distance cosine values, and the angular distance table is constructed based on the sorting results and the star numbers of the corresponding pairs. For example... Figure 2 As shown, the angular distance table includes a sequence number, the star numbers of the two corresponding stars in the HIP star catalog, and the corresponding angular distance cosine value. The stars are arranged in ascending order of their angular distance cosine values.

[0046] When calculating the angular distance between two stars in a star pair, the stars in the HIP catalog can be represented by the following vector v of length 3. p express:

[0047]

[0048] Among them, Ra p Dec represents the right ascension of the star with the asterisk p. p This indicates the declination of the star with the star number p, where p represents the star number in the HIP catalog.

[0049] Next, calculate the cosine of the angular distance between the star pairs using the following formula: cosθ pq :

[0050]

[0051] Where p and q represent the star numbers of the two stars in the HIP catalog, respectively, and v p ,v q Let Dec represent the vectors of the two stars respectively. p Dec represents the declination of star p. q Ra represents the declination of star q. p Ra represents the right ascension of star p. q This represents the right ascension of the star q.

[0052] Step S130: Divide the angular distance table into equal regions and connect the beginning and end of the corresponding serial numbers of each region with straight lines to obtain the segmented straight lines corresponding to each region.

[0053] In this embodiment, after constructing the angular distance table, it is necessary to construct the segmented straight lines l1, l2, ..., l representing the angular distance table. n The number of segmented lines is set according to the actual situation, generally taken as 10, i.e., n=10. Specifically, firstly, the start and end positions of each segmented line need to be set. Generally, after dividing the angular distance table into equal regions, the start and end points of each region are connected by straight lines to obtain the segmented lines corresponding to each region. For example, for an angular distance table with a total of N, it is divided into n equal parts according to the number of segments, i.e. There are n interval regions in total, and the value range corresponding to each region is... Where s(t) represents the angular cosine of the t-th element in the angular distance table. Connecting the beginning and end of the corresponding serial numbers of each region yields the piecewise lines corresponding to each region, with the i-th piecewise line l... i Represented as:

[0054] l i :cosθ ij =k i x+b i ,

[0055] Where, k i Represents a piecewise straight line l i The slope, b i Represents a piecewise straight line l i The intercept;

[0056] Furthermore, the slope k is calculated using the following formula. i and intercept b i :

[0057]

[0058] Among them, D i This represents the element spacing in the i-th region. n i This represents the number of angle distances for the corresponding region in the angle distance table, and s(t) represents the cosine value of the angle distance for the t-th element in the angle distance table, i.e. and This represents the first and last angular distance cosine values ​​in the i-th region of the angular distance table.

[0059] Step S140: Construct K-vectors for each region based on all segmented straight lines to obtain a K-vector lookup table;

[0060] In this embodiment, after the piecewise straight lines are constructed, K-vectors can be constructed for each region based on the piecewise straight lines to obtain a K-vector lookup table. The K-vector construction rules are as follows:

[0061] K i (x)=t,s(t)≤k i x+b i <s(t+1),

[0062] In the formula, K i (x) represents the K vector of the t-th star pair in the angular distance table, s(t) represents the angular distance cosine of the t-th star pair in the angular distance table, and k i Let b represent the slope of the i-th segment of the straight line. i This represents the intercept of the i-th segment of the line. Its physical meaning is that the x-th element of the K vector represents the angular distance less than k in the table. i x+b i The number of values, i.e., K i The cosine of the angular distance between (x) star pairs is less than k. i x+b i .

[0063] Step S150: Obtain the target angular distance between the target navigation star pairs to be identified, and calculate the matching range of the target navigation star pairs in the angular distance table based on the target angular distance, the preset measurement error and the K vector lookup table;

[0064] Step S160: Based on the triangle star map matching algorithm and the matching range, the target navigation star pair is identified to obtain the final identification result.

[0065] In this embodiment, based on the K-vector lookup table, the matching range can be calculated according to the target angular distance of the target navigation satellite pair and the preset measurement error. The calculation process specifically includes: determining the cosine value range of the target navigation satellite pair in the angular distance table based on the target angular distance and the preset measurement error; determining the line positions of the start and end positions of the cosine value range on the corresponding line segments based on the segmented straight lines of the regions corresponding to the start and end positions of the cosine value range, thus obtaining the start line position and the end line position; and calculating the matching range of the target navigation satellite pair in the angular distance table based on the K-vector of the region corresponding to the start line position and the end line position, thus obtaining the matching range.

[0066] For example, for a target navigation star pair (u,v) to be matched in a star chart, the angular distance between them is calculated to be θ, and the preset measurement error is δ. The method for finding the position region of the target navigation star pair (u,v) within the tolerance range of the angular distance table is as follows:

[0067] First, determine the region of the target navigation satellite in the angular distance table. Based on the angular distance and the preset measurement error, define (θ+δ) as the upper limit of the angular distance limit for the target navigation satellite to (u,v), and (θ-δ) as the lower limit of the angular distance limit for the target navigation satellite to (u,v). For the upper limit (θ+δ), it can be assumed to belong to the i-th region based on the value range of the aforementioned region. Similarly, for the lower limit (θ-δ), it can be assumed to belong to the j-th region. Calculate its position on the piecewise straight line using the slope and intercept of the corresponding region.

[0068]

[0069] In the formula, x i With x j These represent the angular distance θ on the line l. i and l j The starting and ending points are represented by the floor and ceil functions, respectively, which round down and up. It's important to note that because cosθ is decreasing, cos(θ+δ) is relatively smaller than cos(θ-δ), and floor and ceil rounding effectively expands the range of cosine values.

[0070] Calculate x i With x j Then, by substituting the K vector for the corresponding region, the start and end positions of the matching range of the target navigation star pair (u,v) in the angular distance table can be quickly found:

[0071]

[0072] Where, k start With k endThese represent the starting and ending positions of the matching range of the target navigation satellite pair (u,v) in the angular distance table, respectively. The 1 is used to ensure the range is maintained, further expanding the final result's range by one value, such as... Figure 3 As shown, the matching range obtained by the improved K-vector lookup method is significantly reduced compared to the data volume of the entire angular distance table (more than 200,000 star pairs).

[0073] Finally, star map recognition is performed based on the triangular star map matching algorithm and the matching range to obtain the final recognition result. The triangular star map matching algorithm treats the observed star map as a sub-map of the overall star map, using the angular distances between stars as edges and stars as vertices. It uses line segments, angular distances, and triangles as basic matching elements and organizes the navigation feature table in a specific way. By combining these basic elements, once a unique region matching the conditions is found in the overall star map, that region represents the final matching result of the observed star map.

[0074] This method improves upon the traditional K-vector lookup method by fitting multiple piecewise straight lines to the regions of the angular distance table, constructing K-vectors corresponding to each piecewise straight line. These multiple piecewise straight lines uniformly fit the number of star pairs in the angular distance table, avoiding the problem of the traditional K-vector lookup method fitting the entire angular distance table with a single straight line, which fails to accurately map the table. By mapping star pairs in different regions with multiple piecewise straight lines, the number of mapped pairs is uniform, reducing the amount of data corresponding to each straight line during K-vector lookup, improving lookup speed, reducing memory usage, and effectively enhancing the star map recognition speed.

[0075] This invention also provides a star map recognition device based on an improved K-vector, which is used to execute any of the aforementioned star map recognition methods based on improved K-vectors. Specifically, please refer to... Figure 4 , Figure 4 This is a schematic block diagram of a star map recognition device based on an improved K-vector provided in an embodiment of the present invention.

[0076] like Figure 4 As shown, the star map recognition device 100 based on the improved K-vector includes a temporary star library construction module 110, an angular distance table construction module 120, a region division module 130, a K-vector construction module 140, a matching range calculation module 150, and a recognition module 160.

[0077] The temporary star database construction module 110 is used to calculate the elevation angle of the current observation position relative to each star in the star catalog, and to filter the stars in the star catalog according to the elevation angle, so as to establish a temporary navigation star database with the selected stars.

[0078] The angular distance table construction module 120 is used to take two stars in the temporary navigation star library that belong to the preset angular distance range as a pair of stars, calculate the angular distance of each pair of stars, calculate the angular distance cosine value of the corresponding pair of stars based on the angular distance, and construct the angular distance table with the angular distance cosine value.

[0079] The region division module 130 is used to divide the angular distance table into equal regions and connect the beginning and end of the corresponding serial numbers of each region with straight lines to obtain the segmented straight lines corresponding to each region.

[0080] K-vector construction module 140 is used to construct K-vectors for each region based on all piecewise straight lines, and obtain a K-vector lookup table;

[0081] The matching range calculation module 150 is used to obtain the target angular distance between the target navigation star pairs to be identified, and calculate the matching range of the target navigation star pairs in the angular distance table based on the target angular distance, the preset measurement error and the K vector lookup table;

[0082] The identification module 160 is used to identify the target navigation star pair based on the triangle star map matching algorithm and the matching range, and obtain the final identification result.

[0083] In one embodiment, the matching range calculation module 150 includes:

[0084] The value range determination unit is used to determine the range of cosine values ​​to which the target navigation star pair belongs in the angular distance table based on the target angular distance and the preset measurement error;

[0085] The position determination unit is used to determine the position of the start and end positions of the cosine value range on the corresponding segmented straight lines based on the segmented straight lines of the region corresponding to the start and end positions of the cosine value range, thereby obtaining the position on the start line and the position on the end line.

[0086] The matching range calculation unit is used to calculate the matching range of the target navigation star pair in the angular distance table based on the K vector of the region corresponding to the position on the starting line and the position on the ending line, so as to obtain the matching range.

[0087] This invention also provides a computer device, which includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the improved K-vector-based star map recognition method as described above.

[0088] Another embodiment of the present invention also provides a computer-readable storage medium. This computer-readable storage medium may be a non-volatile computer-readable storage medium. The computer-readable storage medium stores a computer program that, when executed by a processor, causes the processor to perform the improved K-vector-based star map recognition method as described above.

[0089] Those skilled in the art will readily understand that, for the sake of convenience and brevity, the specific working processes of the devices, apparatuses, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here. Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described in terms of function in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this invention.

[0090] In the embodiments provided by this invention, it should be understood that the disclosed devices, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative. For instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. Units with the same function may be grouped into one unit. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. In addition, the coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection through some interfaces, devices, or units, or it may be an electrical, mechanical, or other form of connection.

[0091] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of the embodiments of the present invention, depending on actual needs.

[0092] Furthermore, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0093] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), magnetic disks, or optical disks.

[0094] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A star pattern recognition method based on improved K-vector, characterized in that, The method comprises the following steps: calculating the altitude angle of each star in the star catalog relative to the current observation position, and screening the stars in the star catalog according to the altitude angle to obtain a temporary navigation star library; two stars in the temporary navigation star library within a preset angular distance range are taken as a star pair, the angular distance of each star pair is calculated, the angular distance cosine value of the corresponding star pair is calculated based on the angular distance, and an angular distance table is constructed based on the angular distance cosine value; the angular distance table is divided into equal areas, and the start and end of the corresponding serial numbers of each area are connected by a straight line to obtain a segmented straight line corresponding to each area; K vector construction is performed on each area based on all segmented straight lines to obtain a K vector lookup table; the target angular distance between the target navigation star pair to be identified is obtained, and the matching range of the target navigation star pair in the angular distance table is calculated based on the target angular distance, a preset measurement error and the K vector lookup table; the target navigation star pair is identified based on a triangular star map matching algorithm and the matching range to obtain a final identification result.

2. The star pattern recognition method according to claim 1, characterized in that, The calculation of the altitude angle of each star in the star catalog relative to the current observation position comprises the following steps: the sidereal time of each star in the star catalog is calculated based on the longitude of the current observation position and the corresponding Greenwich sidereal time to obtain the sidereal time; the hour angle of each star in the star catalog is calculated based on the sidereal time and the right ascension of the corresponding star to obtain the hour angle; the altitude angle of each star in the star catalog is calculated based on the hour angle.

3. The star pattern recognition method according to claim 2, wherein The calculation of the altitude angle of each star in the star catalog relative to the current observation position comprises the following steps: The altitude angle is calculated according to the following formula: LHA = LST - Ra, LST = GST + Longitude, where LST represents the sidereal time of the current observation position, Longitude represents the longitude of the current observation position, GST represents the Greenwich sidereal time, Ra represents the right ascension of the star, LHA represents the hour angle, h represents the altitude angle, Dec represents the declination of the star, and Lat represents the latitude of the current observation position.

4. The star pattern recognition method according to claim 1, characterized by, The calculation of the angular distance cosine value of the corresponding star pair based on the angular distance and the construction of the angular distance table based on the angular distance cosine value comprise the following steps: The angular distance cosine value of each star pair is calculated according to the angular distance. The angular distance table is constructed based on the sorting result and the star number of the corresponding star pair.

5. The star pattern recognition method according to claim 4, characterized in that, The calculation of the angular distance cosine value of the corresponding star pair based on the angular distance and the construction of the angular distance table based on the angular distance cosine value comprise the following steps: The angular distance cosine value cos θ is calculated according to the following equation pq : where p, q represent the designations of the two stars in the star catalogue, v p and v q represent the vectors of the two stars, Dec p represents the declination of star p, Dec q represents the declination of star q, Ra p represents the right ascension of star p, and Ra q represents the right ascension of star q.

6. The star pattern recognition method according to claim 1, wherein The K vector lookup table is obtained by performing K vector construction on each area based on all segmented straight lines. The K vector K corresponding to each region is constructed according to the following formula i (x): K i (x) = t, s(t) < k i x + b i s(t + 1), wherein K i (x) represents the K vector of the tth star pair in the angular distance table, s(t) represents the angular distance cosine value of the tth star pair in the angular distance table, k i represents the slope of the ith piecewise straight line, b i represents the intercept of the ith piecewise straight line.

7. The star pattern recognition method according to claim 1, wherein The matching range of the target navigation star pair in the angular distance table is calculated based on the target angular distance, a preset measurement error and the K vector lookup table. The belonging cosine value range of the target navigation star pair in the angular distance table is determined based on the target angular distance and a preset measurement error. The start position and the end position of the cosine value range are determined based on the segmented straight lines of the areas corresponding to the start position and the end position of the cosine value range, respectively. The matching range of the target navigation star pair in the angular distance table is calculated based on the K vector of the corresponding area of the start online position and the end online position, and the matching range is obtained.

8. A star pattern recognition device based on improved K-vector, characterized by, The method comprises the following steps: A temporary star library construction module is configured to calculate the altitude angle of each star in the star table relative to the current observation position, and to screen the stars in the star table according to the altitude angle, so as to obtain the screened stars, and to establish a temporary navigation star library based on the screened stars; An angular distance table construction module is configured to take two stars in the temporary navigation star library within a preset angular distance range as a star pair, to calculate the angular distance of each star pair, and to calculate the angular distance cosine value of the corresponding star pair based on the angular distance, and to construct an angular distance table based on the angular distance cosine value; A region division module is configured to divide the angular distance table into equal regions, and to connect the first end and the last end of the corresponding serial numbers of each region with a straight line, so as to obtain the segmented straight line corresponding to each region; A K vector construction module is configured to construct the K vector of each region based on all the segmented straight lines, so as to obtain a K vector lookup table; A matching range calculation module is configured to obtain the target angular distance between the target navigation star pair to be identified, and to calculate the matching range of the target navigation star pair in the angular distance table based on the target angular distance, a preset measurement error and the K vector lookup table; An identification module is configured to identify the target navigation star pair based on a triangular star map matching algorithm and the matching range, so as to obtain a final identification result.

9. A computer device comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, The processor implements the star map identification method based on the improved K vector when executing the computer program.

10. A computer-readable storage medium, characterized in that, The computer readable storage medium stores the computer program, and the computer program causes the processor to execute the star map identification method based on the improved K vector when the computer program is executed by the processor. The computer readable storage medium stores the computer program, and the computer program causes the processor to execute the star map identification method based on the improved K vector when the computer program is executed by the processor.

Images