Dual-antenna and triple-antenna orientation methods, initial coordinate positioning methods and cameras

Abstract

The present application relates to the field of satellite application technology, and in particular to a dual-antenna, three-antenna orientation method, an initial coordinate positioning method and a camera. The dual-antenna orientation method is applied to a receiver, and the receiver includes a first antenna and a second antenna, including: obtaining a baseline distance between the first antenna and the second antenna, first satellite observation data obtained based on the first antenna, and second satellite observation data obtained based on the second antenna; determining the initial coordinates of the reference position corresponding to the first antenna based on the first satellite observation data; determining the mobile position coordinates corresponding to the second antenna based on the initial coordinates of the reference position, the baseline length, the first satellite observation data and the second satellite observation data; determining the direction parameters of the receiver based on the initial coordinates of the reference position and the mobile position coordinates. The present application can improve the accuracy of antenna orientation.

Description

Technical Field

[0001] The present application relates to the field of satellite application technology, and in particular to a dual-antenna, triple-antenna orientation method, an initial coordinate positioning method and a camera. Background Art

[0002] With the continuous development of science and technology, the application of smart cameras is becoming more and more extensive, such as in social security and other aspects. Accurate positioning or orientation helps users improve efficiency and complete tasks quickly. However, the positioning and orientation accuracy of existing cameras needs to be improved. Summary of the invention

[0003] In view of this, the embodiments of the present application provide a dual-antenna, triple-antenna orientation method, an initial coordinate positioning method and a camera, which can effectively improve the orientation accuracy, etc.

[0004] In a first aspect, an embodiment of the present application provides a dual-antenna direction-directing method, which is applied to a receiver, wherein the receiver includes a first antenna and a second antenna, including:

[0005] Acquire a baseline distance between the first antenna and the second antenna, first satellite observation data acquired based on the first antenna, and second satellite observation data acquired based on the second antenna;

[0006] Determine, based on the first satellite observation data, initial coordinates of a reference position corresponding to the first antenna;

[0007] Determine the mobile position coordinates corresponding to the second antenna based on the reference position initial coordinates, the baseline length of the baseline, the first satellite observation data and the second satellite observation data;

[0008] The direction parameter of the receiver is determined according to the reference position initial coordinates and the moving position coordinates.

[0009] In some implementation methods, determining the moving position coordinates of the second antenna based on the reference position initial coordinates, the baseline length and the second satellite observation data includes:

[0010] Determine a double-difference phase observation equation group and a double-difference pseudo-range observation equation group according to the first satellite observation data and the second satellite observation data;

[0011] Determining a dual-antenna constraint equation according to the baseline length and the initial coordinates of the reference position;

[0012] The mobile position coordinates are determined according to the double-difference phase observation equation group, the double-difference pseudo-range observation equation group and the dual-antenna constraint equation.

[0013] In some implementation methods, determining the direction parameter of the receiver according to the reference position initial coordinates and the mobile position coordinates includes:

[0014] Determine a corresponding coordinate vector set in a station center coordinate system according to the reference position initial coordinates, the mobile position coordinates and a coordinate conversion matrix, wherein the station center coordinate system is a coordinate system with the reference position as the origin;

[0015] According to the coordinate vector set, the direction parameters of the receiver are determined, and the direction parameters include a heading angle and a pitch angle.

[0016] In a second aspect, the present application further provides a three-antenna direction-directing method, applied to a receiver, wherein the receiver includes a first antenna, a second antenna, and a third antenna, including:

[0017] Acquire first satellite observation data acquired based on the first antenna, second satellite observation data acquired based on the second antenna, third satellite observation data acquired based on the third antenna, and baseline lengths between the first antenna, the second antenna, and the third antenna;

[0018] Obtaining corresponding first antenna initial coordinates, second antenna initial coordinates, and third antenna initial coordinates according to the first satellite observation data, the second satellite observation data, and the third satellite observation data, respectively;

[0019] Determine the first antenna target coordinates, the second antenna target coordinates and the third antenna target coordinates based on each of the antenna initial coordinates, each of the baseline lengths and each of the satellite observation data;

[0020] According to each of the antenna target coordinates, a direction parameter of the receiver is determined.

[0021] In some implementation methods, determining the first antenna target coordinates, the second antenna target coordinates, and the third antenna target coordinates based on each of the antenna initial coordinates, each of the baseline lengths, and each of the satellite observation data includes:

[0022] Determine a double-difference phase observation equation group and a double-difference pseudo-range observation equation group corresponding to each antenna according to each of the satellite observation data;

[0023] Determine a three-antenna constraint equation group according to each baseline length and each antenna initial coordinate;

[0024] According to each of the double-difference phase observation equation groups, each of the double-difference pseudo-range observation equation groups and the three-antenna constraint equations, the first antenna target coordinates, the second antenna target coordinates and the third antenna target coordinates are determined.

[0025] In some implementation methods, determining the direction parameter of the receiver according to each of the antenna target coordinates includes:

[0026] Determine a coordinate vector set corresponding to each baseline in the station center coordinate system according to each of the antenna target coordinates and the coordinate conversion matrix;

[0027] According to each of the coordinate vector sets, direction parameters of the receiver are determined, and the direction parameters include a heading angle and a pitch angle.

[0028] In a third aspect, the present application further proposes an antenna initial coordinate positioning method, which is applied to the above-mentioned receiver, wherein the satellite observation data is satellite single-frequency observation data, and the method comprises:

[0029] Obtain satellite single-frequency observation data, broadcast ephemeris and correction data for each satellite;

[0030] For a single satellite, determining the satellite orbit and the satellite clock error of the satellite according to the broadcast ephemeris of the satellite, and correcting the satellite orbit and the satellite clock error of the satellite according to the correction data of the satellite;

[0031] Determine a pseudorange observation equation and a phase observation equation of the satellite according to the satellite single-frequency observation data of the satellite, the corrected satellite clock error and the corrected satellite orbit;

[0032] Determine the single-frequency half-sum model carrier observation equation of the satellite based on the single-frequency half-sum model, the pseudo-range observation equation of the satellite and the phase observation equation;

[0033] The initial coordinates are determined according to a single-frequency half-sum model observation equation group consisting of the single-frequency half-sum model carrier observation equation of each satellite and the pseudo-range observation equation of each satellite.

[0034] In some implementation methods, the correction data is a correction number broadcast based on the PPP-B2b signal of the Beidou-3 satellite navigation system.

[0035] In some implementations, the single frequency half-sum model carrier observation equation is:

[0036]

[0037] in, is the carrier phase observation value, is the original pseudorange observation value, is the original observed value of the phase, is the distance between the satellite and the antenna phase center, dt r is the receiver clock error, is the satellite clock error, is the phase ambiguity, λ is the wavelength, is the combined pseudorange error of the pseudorange observation noise and the first unmodeled error, is the combined phase error of the phase observation noise and the second unmodeled error, and c is the speed of light.

[0038] In a fourth aspect, an embodiment of the present application provides a high-precision positioning and orientation camera, the camera comprising a receiver, the receiver comprising a memory, a processor and at least two antennas;

[0039] The antenna is used to receive satellite observation data, the memory is used to store a computer program, and the processor is used to execute the computer program to implement the above method based on the satellite observation data.

[0040] The embodiments of the present application have the following beneficial effects:

[0041] The dual-antenna orientation method of the present application includes: obtaining the baseline distance between the first antenna and the second antenna, the first satellite observation data obtained based on the first antenna, and the second satellite observation data obtained based on the second antenna; determining the initial coordinates of the reference position corresponding to the first antenna based on the first satellite observation data; determining the mobile position coordinates corresponding to the second antenna based on the initial coordinates of the reference position, the baseline length, the first satellite observation data, and the second satellite observation data; determining the direction parameters of the receiver based on the initial coordinates of the reference position and the mobile position coordinates. The present application can improve the accuracy of antenna orientation. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0043] Figure 1 An application scenario diagram of the dual-antenna direction-direction method proposed in an embodiment of the present application is shown;

[0044] Figure 2 A first flow chart of the dual-antenna direction-direction method proposed in an embodiment of the present application is shown;

[0045] Figure 3 A second flow chart of the dual-antenna direction-direction method proposed in an embodiment of the present application is shown;

[0046] Figure 4 A third flow chart of the dual-antenna direction-direction method proposed in an embodiment of the present application is shown;

[0047] Figure 5 An application scenario diagram of the three-antenna direction-direction method proposed in an embodiment of the present application is shown;

[0048] Figure 6 A first flow chart of the three-antenna orientation method proposed in an embodiment of the present application is shown;

[0049] Figure 7 A second flow chart of the three-antenna direction-direction method proposed in an embodiment of the present application is shown;

[0050] Figure 8 A third flow chart of the three-antenna orientation method proposed in the embodiment of the present application is shown;

[0051] Fig. 9 A schematic diagram of the process of the antenna initial coordinate positioning method proposed in an embodiment of the present application is shown;

[0052] Fig.10 A schematic diagram of the structure of a first camera proposed in an embodiment of the present application is shown;

[0053] Fig.11 A schematic diagram of the second camera mechanism proposed in an embodiment of the present application is shown. DETAILED DESCRIPTION

[0054] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments.

[0055] The components of the embodiments of the present application generally described and shown in the drawings herein may be arranged and designed in various configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the application claimed for protection, but merely represents the selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present application.

[0056] Hereinafter, the terms "including", "having" and their cognates that can be used in various embodiments of the present application are intended only to indicate specific features, numbers, steps, operations, elements, components or a combination of the foregoing items, and should not be understood as first excluding the existence of one or more other features, numbers, steps, operations, elements, components or a combination of the foregoing items or increasing the possibility of one or more features, numbers, steps, operations, elements, components or a combination of the foregoing items. In addition, the terms "first", "second", "third" and the like are only used to distinguish descriptions and cannot be understood as indicating or implying relative importance.

[0057] Unless otherwise defined, all terms (including technical terms and scientific terms) used herein have the same meanings as those generally understood by those skilled in the art to which the various embodiments of the present application belong. The terms (such as those defined in generally used dictionaries) will be interpreted as having the same meanings as the contextual meanings in the relevant technical field and will not be interpreted as having idealized meanings or overly formal meanings unless clearly defined in the various embodiments of the present application.

[0058] In conjunction with the accompanying drawings, some embodiments of the present application are described in detail below. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0059] Some receivers have positioning and orientation functions. In the corresponding positioning and orientation tasks, the positioning and orientation accuracy of the receiver can more accurately determine the position of the camera, thereby more accurately determining the position of the target person or object, so that the efficiency of task completion is improved. However, the positioning or orientation accuracy of existing receivers is still insufficient.

[0060] Therefore, the present application proposes a dual-antenna orientation method, a three-antenna orientation method and an antenna positioning method to improve the positioning or orientation accuracy of the receiver, which is suitable for a variety of application scenarios.

[0061] Receiver orientation usually refers to determining the heading and pitch angles of a receiver by measuring the distance between two receivers (baseline vector). This method does not require knowing the absolute position of the receiver, but rather compares the relative positions of the two receivers.

[0062] Receiver positioning usually receives satellite signals through antennas and measures the signal propagation time, and uses the principle of triangulation to calculate its own three-dimensional coordinates. The principle of triangulation refers to the use of two or more detectors to detect the target's position at different locations, and then use the principle of triangulation geometry to determine the target's position and distance.

[0063] In some application scenarios, such as cameras, autonomous driving, radar, fishing, road construction and other fields, it is usually necessary to combine the position and direction of the receiver to perform comprehensive calculations to achieve the corresponding functions. Since the positioning method and the orientation method do not necessarily rely on each other, this application is explained from the two aspects of positioning and orientation respectively.

[0064] In terms of direction-finding, common direction-finding usually uses two receivers, each receiver corresponds to an antenna, and one of the fixed receivers is used as a base station, and the other mobile receiver is used as a mobile station. However, the receiver of this application includes multiple antennas, which can be two antennas, three antennas or more. The following describes the dual-antenna and three-antenna receiver direction-finding respectively.

[0065] Example 1

[0066] Figure 1 A schematic structural diagram of a dual-antenna receiver 10 according to an embodiment of the present application is shown. Exemplarily, the dual-antenna receiver 10 includes: a first antenna 11, a second antenna 12, a processor (not shown) and a memory (not shown).

[0067] Those skilled in the art should understand that Figure 1 The structure of the dual-antenna receiver 10 shown does not constitute a limitation of the embodiment of the present application, and the dual-antenna receiver 10 may also include more or less other hardware or software than shown in the figure, or different component arrangements. For example, the receiver may also include a noise amplifier, a demodulator, a baseband processor, etc., and may also include a superheterodyne unit, a direct conversion unit and / or a frequency conversion unit, etc., wherein the superheterodyne unit is used to convert the radio frequency signal into an intermediate frequency signal; the direct conversion unit is used to convert the radio frequency signal into a baseband signal; and the frequency conversion unit is used to convert the radio frequency signal into a DC signal.

[0068] It should be noted that the dual-antenna receiver 10 of the above structure is only an example, and other existing or future electronic products that are suitable for the present application should also be included in the protection scope of the present application and included here by reference.

[0069] Figure 2 is a flow chart of a dual-antenna directional method provided in an embodiment of the present application, wherein the dual-antenna directional method is applied to a receiver including at least two antennas (for example, Figure 1 The dual antenna receiver 10 in FIG. Figure 2 As shown, the dual-antenna direction-directing method may include the following steps. The order of the steps in the flowchart may be changed according to different requirements.

[0070] Step S110 , obtaining a baseline distance between the first antenna 11 and the second antenna 12 , first satellite observation data obtained based on the first antenna 11 , and second satellite observation data obtained based on the second antenna 12 .

[0071] In some embodiments, the baseline distance between the first antenna 11 and the second antenna 12 can be the straight-line distance between the first antenna 11 and the second antenna 12. The baseline distance can be directly obtained by measurement. Of course, other methods can also be selected according to actual needs. For example, if meter-level positioning is required, standard point positioning (SPP) can be selected; if sub-meter level is required, Beidou-3 precise point positioning technology (PPP-B2b) can be selected; if centimeter level is required, real-time dynamic differential positioning technology (RTK) can be selected, etc., and there is no restriction here. The coordinates of the first antenna 11 and the second antenna 12 are calculated by the above three positioning technologies, and then the baseline distance is calculated. Among them, the satellite observation data includes pseudorange observations, carrier phase observations, broadcast ephemeris, etc.

[0072] Step S120: Determine the initial coordinates of the reference position corresponding to the first antenna 11 according to the first satellite observation data.

[0073] In some embodiments, one of the antennas is used as a reference antenna, and the position of the reference point corresponding to the reference antenna is used as the reference position. The initial coordinates of the reference position remain unchanged in the subsequent solution process. The other antenna is used as a mobile antenna, and the reference point corresponding to the mobile antenna is used as the mobile position. The coordinates of the mobile position can be regarded as unknown parameters and need to be solved and corrected later.

[0074] Step S130: Determine the moving position coordinates corresponding to the second antenna 12 based on the reference position initial coordinates, the baseline length, the first satellite observation data and the second satellite observation data.

[0075] In some embodiments, the satellite observation data observed by each antenna is different. The calculation of the mobile position coordinates uses differential positioning technology. Therefore, it is necessary to calculate the corresponding mobile position coordinates based on the first satellite observation data and the second satellite observation data. During the calculation process, the mobile position solution needs to be corrected using the reference position initial coordinates. Among them, the baseline length is used to constrain the mobile position coordinates to make them more accurate.

[0076] Step S140: Determine the direction parameters of the receiver according to the initial coordinates of the reference position and the coordinates of the moving position.

[0077] The heading angle and elevation angle of the dual-antenna receiver 10 (hereinafter referred to as the receiver) are determined by calculating the baseline vector between the two antennas according to the reference position initial coordinates and the moving position coordinates. The direction parameters include the heading angle and the elevation angle.

[0078] The four complete steps of dual-antenna orientation have been introduced above. The following will respectively introduce step S130 and step S140 in detail:

[0079] First, step S130 is introduced. In some embodiments, Figure 3 As shown, step S130, based on the initial coordinates of the reference position, the baseline length, the first satellite observation data and the second satellite observation data, determines the moving position coordinates of the second antenna 12, including:

[0080] Step S131, determining a double difference phase observation equation group and a double difference pseudorange observation equation group according to the first satellite observation data and the second satellite observation data.

[0081] In some embodiments, the first antenna 11 and the second antenna 12 may both observe a number of satellites (the first antenna 11 and the second antenna 12 may observe different numbers of satellites). If the number of satellites observed by the first antenna 11 and the second antenna 12 is (n+1), one of the satellites is used as a reference satellite, and the number of non-reference satellites is n. Then, n double-difference phase observation equations and n double-difference pseudo-range observation equations may be established, and the n double-difference phase observation equations may be combined into the above-mentioned double-difference phase observation equation group, and the n double-difference pseudo-range observation equations may be combined into the above-mentioned double-difference pseudo-range observation equation group.

[0082] Exemplarily, if the first antenna 11C and the second antenna 12A both observe the reference satellite p and the non-reference satellite q, the double difference phase observation equation and the double difference pseudorange observation equation between the first antenna 11C, the second antenna 12A, the reference satellite p and the non-reference satellite q are respectively:

[0083]

[0084] Where λ is the carrier wavelength, is the double-difference carrier phase observation value, is the double difference distance from the receiver to the satellite, for The carrier ambiguity, is the observation noise of the carrier phase, is the double-difference pseudorange observation value, is the observation noise of the pseudorange.

[0085] Similarly, the first antenna 11C, the second antenna 12A, the reference satellite p and the non-reference satellite q1, ..., the first antenna 11C, the second antenna 12A, the reference satellite p and the non-reference satellite q n-1 between, the first antenna 11C, the second antenna 12A, the reference satellite p and the non-reference satellite q n A double-difference phase observation equation and a double-difference pseudo-range observation equation can be established.

[0086] Regarding the determination of n, there are a total of These (n+3) unknown parameters, among which (x A ,y A , z A ) represents the moving position coordinates of the second antenna 12, Based on the first antenna 11A, the second antenna 12C, the reference satellite p and the non-reference satellite q n Calculated ambiguity. In order to calculate these (n+3) unknown parameters, at least (n+3) equations are required, so there are 2n double-difference observation equations in total, so 2n≥3+n, that is, n is an integer greater than or equal to 3, that is, satellite observation data from at least 3 non-reference satellites are required.

[0087] Step S132: Determine the dual-antenna constraint equation according to the baseline length and the initial coordinates of the reference position.

[0088] In some embodiments, since the baseline length between the dual antennas on the receiver can be regarded as a fixed value, a dual antenna constraint equation can be constructed based on the baseline length, the initial coordinates of the reference position, and the mobile position coordinates of the second antenna 12 to improve the accuracy of the solved mobile position coordinates.

[0089] Exemplarily, the dual antenna constraint equation may be:

[0090]

[0091] Among them, (x C ,y C , z C ) represents the initial coordinates of the reference position of the first antenna 11, L AC It can be obtained through measurement or other methods, and there is no restriction here.

[0092] Step S133, determining the mobile position coordinates according to the double-difference phase observation equation group, the double-difference pseudo-range observation equation group and the dual-antenna constraint equation.

[0093] Each double-difference phase observation equation, each double-difference pseudo-range observation equation and the dual-antenna constraint equation are combined into a comprehensive equation group, and the mobile position coordinates are obtained by solving the comprehensive equation group.

[0094] Next, step S140 is introduced, in which the direction parameters of the receiver are determined according to the initial coordinates of the reference position and the coordinates of the moving position, such as Figure 4 As shown, in some embodiments, step S140 includes:

[0095] Step S141, determine the corresponding coordinate vector set in the station center coordinate system according to the initial coordinates of the reference position, the moving position coordinates and the coordinate conversion matrix, and the station center coordinate system is a coordinate system with the reference position as the origin.

[0096] In some embodiments, since the mobile position coordinates obtained above are coordinates in the Earth-Centered Earth-Fixed (ECEF) coordinate system, in order to simplify spatial calculations and facilitate cognition, the coordinate vectors in the Earth-centered Earth-Fixed coordinate system need to be converted to obtain the coordinate vectors in the Earth-fixed coordinate system (ENU) station-centered coordinate system.

[0097] Exemplarily, the coordinate transformation matrix R ECEF-ENU Can be:

[0098]

[0099] Among them, B represents the latitude of the reference position, and L represents the longitude of the reference position.

[0100] Exemplarily, the target position vector is obtained according to the initial coordinates of the reference position and the moving position coordinates; the target position vector is converted into a corresponding coordinate vector set in the station center coordinate system according to the coordinate conversion matrix; wherein the conversion formula can be:

[0101]

[0102] in, represents the coordinate vector in the station center coordinate system, Indicates the target position vector of the moving position to the reference position, ENU rb is the coordinate vector in the transformed station center coordinate system.

[0103] Step S142: Determine the direction parameters of the receiver according to the coordinate vector set, where the direction parameters include a heading angle and a pitch angle.

[0104] In some embodiments, after obtaining the coordinate vector set, the easting coordinate difference, northing coordinate difference and celestial coordinate difference are determined according to the coordinate vector set; the direction parameter is determined according to the easting coordinate difference, northing coordinate difference and celestial coordinate difference.

[0105] For example, the calculation formulas for the heading angle and the pitch angle are:

[0106]

[0107] Among them, E rb Indicates the easting coordinate difference, N rb North coordinate difference, U rb Celestial coordinate difference.

[0108] The dual-antenna orientation method of the present application includes: obtaining the baseline distance between the first antenna 11 and the second antenna 12, the first satellite observation data obtained based on the first antenna 11, and the second satellite observation data obtained based on the second antenna 12; determining the initial coordinates of the reference position corresponding to the first antenna 11 based on the first satellite observation data; determining the mobile position coordinates corresponding to the second antenna 12 based on the initial coordinates of the reference position, the baseline length, the first satellite observation data and the second satellite observation data; determining the direction parameters of the receiver based on the initial coordinates of the reference position and the mobile position coordinates. The present application can improve the accuracy of antenna orientation.

[0109] Example 2

[0110] Figure 5 A schematic structural diagram of a three-antenna receiver 20 according to Embodiment 2 of the present application is shown. Exemplarily, the three-antenna receiver 20 includes: a first antenna 21, a second antenna 22, a third antenna 23, a processor (not shown) and a memory (not shown).

[0111] Understandably, Figure 5 The structure of the three-antenna receiver 20 shown does not constitute a limitation of the embodiment of the present application, and the three-antenna receiver 20 may also include more or less other hardware or software than shown in the figure, or different component arrangements. For example, the receiver may also include a noise amplifier, a demodulator, a baseband processor, etc., and may also include a superheterodyne unit, a direct conversion unit and / or a frequency conversion unit, etc., wherein the superheterodyne unit is used to convert the radio frequency signal into an intermediate frequency signal; the direct conversion unit is used to convert the radio frequency signal into a baseband signal; and the frequency conversion unit is used to convert the radio frequency signal into a DC signal.

[0112] It should be noted that the three-antenna receiver 20 of the above structure is only an example, and other existing or future electronic products that are suitable for the present application should also be included in the protection scope of the present application and included here by reference.

[0113] Figure 6 is a flow chart of a three-antenna orientation method provided in an embodiment of the present application, wherein the three-antenna orientation method is applied to a receiver including at least three antennas (for example, Figure 5 The three-antenna receiver 20 in FIG. Figure 6 As shown, the three-antenna direction-directing method may include the following steps. The order of the steps in the flowchart may be changed according to different requirements.

[0114] Step S210, obtaining first satellite observation data obtained based on the first antenna 21, second satellite observation data obtained based on the second antenna 22, third satellite observation data obtained based on the third antenna 23, and baseline lengths between the first antenna, the second antenna and the third antenna.

[0115] In some embodiments, since the number of satellites observed by each antenna may be different, and the distances between different antennas and the same satellite may also be different, the satellite observation data obtained by each antenna is different. Therefore, the present application needs to obtain the satellite observation data obtained by each antenna separately to calculate the subsequent initial coordinates of the antenna.

[0116] Step S220: Obtain corresponding first antenna initial coordinates, second antenna initial coordinates, and third antenna initial coordinates according to the first satellite observation data, the second satellite observation data, and the third satellite observation data, respectively.

[0117] In some embodiments, the initial coordinates of the first antenna can be calculated based on the first satellite observation data, the initial coordinates of the second antenna can be calculated based on the second satellite observation data, and the initial coordinates of the third antenna can be calculated based on the third satellite observation data. The initial coordinates of the antenna refer to the coordinates of the reference / flow position corresponding to the antenna when it is first calculated.

[0118] In some embodiments, the initial coordinates of the antenna can be determined by Real-Time Kinematic (RTK) positioning technology. Of course, other methods can also be used, which are not limited here and can be selected according to specific needs. For example, if meter-level positioning is required, standard point positioning (SPP) can be selected; if sub-meter level positioning is required, Beidou-3 precise point positioning technology (PPP-B2b) can be selected; if centimeter level positioning is required, RTK positioning technology can be selected.

[0119] The definition of the baseline length may refer to the definition of the baseline length between the two antennas described above, which will not be repeated here.

[0120] For example, it is assumed that the three-antenna receiver 20 (hereinafter referred to as the receiver) includes antenna A, antenna B and antenna C, and the baseline lengths between the two antennas are the baseline lengths L between antenna A and antenna B. AB , the baseline length L between antenna A and antenna C AC , the baseline length L between antenna B and antenna C BC .

[0121] Optionally, the positions of the three antennas may form three vertices of a triangle, and of course may be other layout positions, which are not limited here.

[0122] Step S230: Determine the first antenna target coordinates, the second antenna target coordinates, and the third antenna target coordinates based on each baseline length and each satellite observation data.

[0123] In some embodiments, the above-mentioned antenna initial coordinates are used to calculate the relative distance between each two antennas, that is, the baseline length, but calculating the direction of the receiver requires more accurate relative position coordinates. Therefore, it is necessary to calculate the required more accurate position coordinates according to the method in this embodiment, that is, the antenna target coordinates.

[0124] Step S240: Determine the direction parameters of the receiver according to the target coordinates of each antenna.

[0125] The heading angle and elevation angle of the receiver are determined by calculating the baseline vector between the three antennas according to the target coordinates of each antenna (the first antenna target coordinates, the second antenna target coordinates and the third antenna target coordinates in this embodiment). The direction parameters include the heading angle and the elevation angle.

[0126] The four complete steps of three-antenna orientation have been introduced above. The following will respectively introduce step S230 and step S240 in detail:

[0127] First, step S230 is introduced. In some embodiments, Figure 7 As shown, step S230, based on each antenna initial coordinate, each baseline length and each satellite observation data, determining the first antenna target coordinate, the second antenna target coordinate and the third antenna target coordinate, includes:

[0128] Step S231: Determine the double-difference phase observation equation group and the double-difference pseudo-range observation equation group corresponding to each baseline according to each satellite observation data.

[0129] In some embodiments, a double-difference phase observation equation group and a double-difference pseudo-range observation equation group corresponding to each baseline are determined respectively.

[0130] For example, if the baseline length L between antenna A and antenna B is AB , the baseline length L between antenna A and antenna C AC , the baseline length L between antenna B and antenna C BC . Determine the baseline length L AB , baseline length L AC and the baseline length L BC The double-difference phase observation equations and double-difference pseudorange observation equations.

[0131] With baseline length L AB For example, referring to the method for obtaining the double-difference phase observation equation group and the double-difference pseudo-range observation equation group introduced in Example 1, the baseline length L can be obtained. AB The corresponding double difference phase observation equations and double difference pseudorange observation equations. Assume that the baseline length L ABCorresponding to i common non-reference satellites, i double-difference phase observation equations and i double-difference pseudo-range observation equations can be established, and the i double-difference phase observation equations form the above baseline length L AB The corresponding double-difference phase observation equation group is composed of the i double-difference pseudo-range observation equations into the above baseline length L AB The corresponding double-difference pseudo-range observation equations have a total of These (i+6) unknown parameters, among which (x A ,y A , z A ) represents the moving position coordinates corresponding to the first antenna 21, (x B ,y B , z B ) represents the moving position coordinates corresponding to the second antenna 22, Based on the first antenna 21A, the second antenna 22B, the reference satellite p and the non-reference satellite q i The calculated blur.

[0132] Similarly, the baseline length L can be obtained AC The corresponding j double-difference phase observation equations and j double-difference pseudo-range observation equations have a total of These (j+6) unknown parameters, among which (x A ,y A , z A ) represents the moving position coordinates corresponding to the first antenna 21, (x C ,y C , z C ) represents the moving position coordinates corresponding to the third antenna 23, Based on the first antenna 21A, the second antenna 22C, the reference satellite p and the non-reference satellite q j The calculated ambiguity. The baseline length L can be obtained BC The corresponding k double-difference phase observation equations and k double-difference pseudo-range observation equations have a total of These (k+6) unknown parameters, Based on the second antenna 22B, the third antenna 23C, the reference satellite p and the non-reference satellite q k The calculated blur.

[0133] In summary, there are a total of (9+i+j+k) unknown parameters and at least (9+i+j+k) equations. Based on these equations, the three-antenna constraint equation group is determined.

[0134] Step S232: Determine a set of three-antenna constraint equations according to each baseline length and each antenna initial coordinate.

[0135] In some embodiments, since the three baseline lengths between the three antennas on the receiver can be regarded as fixed values, a three-antenna constraint equation group consisting of three three-antenna constraint equations can be constructed based on the baseline lengths and the mobile position coordinates of the three antennas to improve the accuracy of the solved mobile position coordinates.

[0136] Exemplarily, the three antenna constraint equations are:

[0137]

[0138]

[0139] Among them, L AC , L BC and L AB It can be obtained through measurement or other methods, and there is no restriction here.

[0140] Step S233, determining the first antenna target coordinates, the second antenna target coordinates and the third antenna target coordinates according to each double-difference phase observation equation group, each double-difference pseudo-range observation equation group and the three-antenna constraint equations.

[0141] Each double-difference phase observation equation, each double-difference pseudo-range observation equation and the three-antenna constraint equation are combined into a comprehensive equation group, and the three mobile position coordinates are obtained by solving the comprehensive equation group.

[0142] Next, step S240 is introduced, and the direction parameters of the receiver are determined according to the target coordinates of each antenna, such as Figure 8 As shown, in some embodiments, step S240 includes:

[0143] Step S241: Determine the coordinate vector set corresponding to each baseline in the station center coordinate system according to each antenna target coordinate and the coordinate conversion matrix.

[0144] Since the mobile position coordinates obtained above are coordinates in the Earth-Centered Earth-Fixed (ECEF) Earth-centered Earth-Fixed coordinate system, in order to simplify spatial calculations and facilitate cognition, it is necessary to convert the coordinate vectors in the Earth-centered Earth-Fixed coordinate system to obtain the coordinate vectors in the Earth-fixed coordinate system (ENU). The conversion method can refer to the conversion method in the above embodiment 1, which will not be repeated here. Finally, the coordinate vector set corresponding to each baseline is obtained.

[0145] Step S242: Determine the direction parameters of the receiver according to each coordinate vector set, where the direction parameters include a heading angle and a pitch angle.

[0146] In some embodiments, after obtaining the coordinate vector set, the easting coordinate difference, the northing coordinate difference and the celestial coordinate difference are determined according to the coordinate vector set; and the direction parameter is determined according to the easting coordinate difference, the northing coordinate difference and the celestial coordinate difference. The method for determining the parameters can also refer to the calculation method in the above embodiment 1, which will not be repeated here.

[0147] According to each coordinate vector set, the heading angle and pitch angle corresponding to each baseline are determined.

[0148] For example, the heading angle and pitch angle corresponding to each baseline are respectively AC 、heading AB 、heading BC 、pitch AC 、pitch AB and pitch BC Among them, heading AC is the heading angle corresponding to the baseline AC, pitch AC is the pitch angle corresponding to the baseline AC; AB is the heading angle corresponding to the baseline AB, pitch AB is the pitch angle corresponding to the baseline AB; BC is the heading angle corresponding to the baseline BC, pitch BC is the pitch angle corresponding to the baseline BC.

[0149] Based on each heading angle and each pitch angle, the orientation parameter of the receiver is determined.

[0150] Exemplarily, the calculation formulas for the heading angle and pitch angle of the receiver are:

[0151] heading=heading AC +(heading BC -heading AC ) / 2;

[0152] pitch=pitch AC +(pitch BC -pitch AC ) / 2.

[0153] So far, the dual-antenna orientation method and the three-antenna orientation method of the present application have been introduced. However, it should be noted that there are multiple ways to locate the initial coordinates of the antenna in each of the above-mentioned antenna orientation processes, such as SPP, PPP, RTK, etc. For each antenna, it can be independently located according to the corresponding satellite observation data. In addition, the present application also shows a method for calculating the initial coordinates, as follows:

[0154] Example 3

[0155] Fig. 9 A schematic flow chart of a method for initial antenna coordinate positioning is shown. The method for initial antenna coordinate positioning may include the following steps. According to different requirements, the order of the steps in the flow chart may be changed, and some may be omitted.

[0156] Step S310: Obtain satellite single-frequency observation data, broadcast ephemeris and correction data.

[0157] In some embodiments, the collected satellite observation data is single-frequency observation data, that is, satellite single-frequency observation data. The observation data includes pseudorange observation values ​​and phase observation values. The correction data includes orbit correction parameters, clock correction parameters, inter-code deviation, etc. The correction data can be a correction number broadcast based on the PPP-B2b signal, that is, it can be a correction number broadcast by the GEO satellite of the Beidou-3 satellite navigation system through the PPP-B2b signal, and there is no limitation here.

[0158] Step S320: For a single satellite, determine the satellite orbit and satellite clock error of the satellite according to the broadcast ephemeris of the satellite, and correct the satellite orbit and the satellite clock error of the satellite according to the correction data of the satellite.

[0159] It should be noted that due to the error in the receiver receiving the data, the result calculated based on the received satellite observation data is somewhat different from the true value. From the analysis of the error, it can be seen that part of the error can be corrected through the model or calculation, and the other part of the error is taken as an unknown number and solved together with the three unknown numbers of the x, y, and z axis coordinates of the initial coordinates through the final set of equations. Among them, the error includes but is not limited to satellite clock error, receiver clock error, tropospheric delay error, ionospheric delay error, phase ambiguity, phase observation noise, pseudorange observation noise, etc.

[0160] Optionally, the tropospheric delay error includes a dry delay part and a wet delay part. The dry delay part can be corrected by a model (such as the Saastamoinen model), and the wet delay part can be solved as an unknown. The ionospheric delay error in the carrier observation equation can also be corrected by a model (such as the half-sum model in the following embodiment), and the phase ambiguity is solved as an unknown. The ionospheric delay error in the pseudorange observation equation can be corrected by a model (such as the Klobuchar model). The receiver clock error can also be solved as an unknown. The satellite clock error can be corrected by an algorithm.

[0161] In some embodiments, considering the existence of hardware delay bias, the satellite clock error can be corrected by the inter-code bias. According to the inter-code bias and the satellite clock error corresponding to the observed value of the current frequency, the target satellite clock error, that is, the corrected satellite clock error, is determined.

[0162] Step S330: Determine the pseudorange observation equation and phase observation equation of the satellite according to the satellite single-frequency observation data of the satellite, the corrected satellite clock error and the corrected satellite orbit.

[0163] Step S340: Determine the single-frequency half-sum model carrier observation equation of the satellite based on the single-frequency half-sum model, the pseudo-range observation equation and the phase observation equation of the satellite.

[0164] Step S350, determining the initial coordinates according to the single-frequency half-sum model observation equation group consisting of the single-frequency half-sum model carrier observation equation of each satellite and the pseudo-range observation equation of each satellite.

[0165] First, the pseudorange observation equation and the phase observation equation are introduced as follows:

[0166]

[0167] in, represents the pseudorange observation between the receiver r and the satellite s, represents the phase observation between the receiver r and the satellite s; represents the distance between the satellite s and the phase center of the receiver r antenna; c represents the speed of light; dt r represents the receiver clock error of receiver r; dt s represents the satellite clock error of satellite s; T r represents the tropospheric delay error; represents the ionospheric delay error between the receiver r and the satellite s; λ represents the wavelength; represents the phase ambiguity between the receiver r and the satellite s; represents the combined pseudorange error of the pseudorange observation noise and the first unmodeled error between the receiver r and the satellite s; represents the combined phase error of the phase observation noise and the second unmodeled error between the receiver r and the satellite s.

[0168] The first unmodeled error may include pseudorange multipath error, common mode error when measuring pseudorange, etc.; the second unmodeled error may include phase multipath error, common mode error when measuring phase, etc., which are not limited here. After understanding the pseudorange observation equation and the phase observation equation, the single-frequency half-sum model carrier observation equation of each satellite is determined based on each pseudorange observation equation, each phase observation equation and the single-frequency half-sum model.

[0169] It can be understood that each observed satellite corresponds to a pseudorange observation equation and a phase observation equation between the receiver, and a single-frequency half-sum model carrier observation equation can be obtained based on the pseudorange observation equation and the phase observation equation. Therefore, if the number of satellites observed by the antenna is w, there are w pseudorange observation equations, w phase observation equations and w single-frequency half-sum model carrier observation equations. Then, a single-frequency half-sum model observation equation group is formed based on the w pseudorange observation equations and the w single-frequency half-sum model carrier observation equations, and then the position parameters of the antenna, that is, the initial coordinates, are solved based on the single-frequency half-sum model observation equation group.

[0170] In some embodiments, the single frequency half-sum model carrier observation equation is:

[0171]

[0172] in, represents the carrier phase observation value obtained based on the single-frequency half-sum model, represents the original pseudorange observation value, represents the original observed value of the phase, Indicates the distance between the satellite and the antenna phase center, dt r represents the receiver clock error, represents the satellite clock error, represents the phase ambiguity, λ represents the wavelength, represents the combined pseudorange error of the pseudorange observation noise and the first unmodeled error, represents the comprehensive phase error of phase observation noise and the second unmodeled error, and c represents the speed of light.

[0173] It should be noted that the original phase observation values ​​and pseudorange observation values ​​are all from the satellite single-frequency observation data, that is, they have not been corrected. It is obtained after correction.

[0174] Of course, in some embodiments, the initial coordinates of the reference position in the above-mentioned embodiment 1 or the initial coordinates of the antenna used in the positioning method in embodiment 2 can be obtained by the initial coordinate positioning method of the antenna in embodiment 3. There is no limitation here and it can also be obtained by other positioning methods.

[0175] The positioning method of the present application includes: obtaining satellite single-frequency observation data, broadcast ephemeris and correction data of each satellite; for a single satellite, determining the satellite orbit and satellite clock error of the satellite according to the broadcast ephemeris of the satellite, and correcting the satellite orbit and satellite clock error of the satellite according to the correction data of the satellite; determining the pseudo-range observation equation and phase observation equation of the satellite according to the satellite single-frequency observation data of the satellite; determining the single-frequency half-sum model carrier observation equation of the satellite based on the single-frequency half-sum model, the pseudo-range observation equation and the phase observation equation of the satellite; determining the initial coordinates according to the single-frequency half-sum model observation equation group composed of the single-frequency half-sum model carrier observation equation of each satellite and the pseudo-range observation equation of each satellite. The present application can improve the accuracy of antenna positioning under single-frequency carrier.

[0176] Example 4

[0177] The present application also proposes a high-precision positioning and directional camera, which includes a receiver, which includes a memory, a processor and several antennas. The memory is used to store computer programs, the antenna is used to receive satellite observation data, and the processor is used to execute the computer program to implement the above method based on the satellite observation data.

[0178] It can be understood that the device of this embodiment corresponds to the method of the above embodiment, and the options in the above embodiment are also applicable to this embodiment, so they will not be described repeatedly here.

[0179] It should be noted that the methods of the above-mentioned embodiments 1 to 3 can also be applied to other devices, for example, vehicles such as cars and airplanes, or positioning devices such as radars, etc., and there is no limitation here.

[0180] In some embodiments, Figure 10 to Figure 11 A dual-antenna camera and a triple-antenna camera are shown respectively, wherein the dual-antenna camera 300 includes antenna A and antenna B, and the triple-antenna camera 400 includes antenna C, antenna D, and antenna E. Of course, Figure 10 to Figure 11 The position and number of antennas in the embodiment are just an example and do not constitute a limitation on the position and number of camera antennas in embodiment 4.

[0181] Among them, the processor can be an integrated circuit chip with signal processing capabilities. The processor can be a general-purpose processor, including a central processing unit (CPU), a graphics processing unit (GPU) and a network processor (NP), a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA) or at least one of other programmable logic devices, discrete gates or transistor logic devices, and discrete hardware components. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor, etc., which can implement or execute the disclosed methods, steps and logic block diagrams in the embodiments of the present application.

[0182] The memory may be, but is not limited to, a random access memory (RAM), a read only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), etc. The memory is used to store a computer program, and the processor may execute the computer program accordingly after receiving an execution instruction.

[0183] The present application also provides a computer-readable storage medium for storing the computer program used in the above-mentioned camera. For example, the computer-readable storage medium may include but is not limited to: a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, and other media that can store program codes.

[0184] In several embodiments provided in the present application, it should be understood that the disclosed devices and methods can also be implemented in other ways. The device embodiments described above are merely schematic. For example, the flowcharts and structure diagrams in the accompanying drawings show the possible architecture, functions and operations of the devices, methods and computer program products according to multiple embodiments of the present application. In this regard, each box in the flowchart or block diagram can represent a module, a program segment or a part of a code, and the module, a program segment or a part of a code contains one or more executable instructions for implementing the specified logical function. It should also be noted that in an alternative implementation, the functions marked in the box can also occur in a different order from the order marked in the accompanying drawings. For example, two consecutive boxes can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the structure diagram and / or the flow diagram, and the combination of boxes in the structure diagram and / or the flow diagram, can be implemented with a dedicated hardware-based system that performs a specified function or action, or can be implemented with a combination of dedicated hardware and computer instructions.

[0185] In addition, the functional modules or units in the various embodiments of the present application may be integrated together to form an independent part, or each module may exist separately, or two or more modules may be integrated to form an independent part.

[0186] If the functions are implemented in the form of software function modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for a computer device (which can be a smart phone, a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods described in the various embodiments of the present application.

[0187] The above description is only a specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application.

Claims

1. A dual-antenna direction-direction method, characterized in that: Applied to a receiver, the receiver comprising a first antenna and a second antenna, including: Acquire a baseline distance between the first antenna and the second antenna, first satellite observation data acquired based on the first antenna, and second satellite observation data acquired based on the second antenna; Determine, based on the first satellite observation data, initial coordinates of a reference position corresponding to the first antenna; Determine the mobile position coordinates corresponding to the second antenna based on the reference position initial coordinates, the baseline length of the baseline, the first satellite observation data and the second satellite observation data; The direction parameter of the receiver is determined according to the reference position initial coordinates and the moving position coordinates.

2. The dual-antenna direction-directing method according to claim 1, characterized in that: The step of determining the moving position coordinates of the second antenna based on the reference position initial coordinates, the baseline length and the second satellite observation data comprises: Determine a double-difference phase observation equation group and a double-difference pseudo-range observation equation group according to the first satellite observation data and the second satellite observation data; Determining a dual-antenna constraint equation according to the baseline length and the initial coordinates of the reference position; The mobile position coordinates are determined according to the double-difference phase observation equation group, the double-difference pseudo-range observation equation group and the dual-antenna constraint equation.

3. The dual-antenna direction-directing method according to any one of claims 1 to 2, characterized in that: The step of determining the direction parameter of the receiver according to the reference position initial coordinates and the mobile position coordinates comprises: Determine a corresponding coordinate vector set in a station center coordinate system according to the reference position initial coordinates, the mobile position coordinates and a coordinate conversion matrix, wherein the station center coordinate system is a coordinate system with the reference position as the origin; According to the coordinate vector set, the direction parameters of the receiver are determined, and the direction parameters include a heading angle and a pitch angle.

4. A three-antenna direction-direction method, characterized in that: Applied to a receiver, the receiver includes a first antenna, a second antenna and a third antenna, including: Acquire first satellite observation data acquired based on the first antenna, second satellite observation data acquired based on the second antenna, third satellite observation data acquired based on the third antenna, and baseline lengths between the first antenna, the second antenna, and the third antenna; Obtaining corresponding first antenna initial coordinates, second antenna initial coordinates, and third antenna initial coordinates according to the first satellite observation data, the second satellite observation data, and the third satellite observation data, respectively; Determine a first antenna target coordinate, a second antenna target coordinate, and a third antenna target coordinate based on each of the antenna initial coordinates, each of the baseline lengths, and each of the satellite observation data; According to each of the antenna target coordinates, a direction parameter of the receiver is determined.

5. The three-antenna direction-direction method according to claim 4, characterized in that: The determining of the first antenna target coordinates, the second antenna target coordinates and the third antenna target coordinates based on each of the antenna initial coordinates, each of the baseline lengths and each of the satellite observation data comprises: Determine a double-difference phase observation equation group and a double-difference pseudo-range observation equation group corresponding to each antenna according to each of the satellite observation data; Determine a three-antenna constraint equation group according to each baseline length and each antenna initial coordinate; According to each of the double-difference phase observation equation groups, each of the double-difference pseudo-range observation equation groups and the three-antenna constraint equations, the first antenna target coordinates, the second antenna target coordinates and the third antenna target coordinates are determined.

6. The three-antenna direction-directing method according to any one of claims 4 to 5, characterized in that: Determining the direction parameter of the receiver according to each of the antenna target coordinates includes: Determine a coordinate vector set corresponding to each baseline in the station center coordinate system according to each of the antenna target coordinates and the coordinate conversion matrix; According to each of the coordinate vector sets, direction parameters of the receiver are determined, and the direction parameters include a heading angle and a pitch angle.

7. A method for initial antenna coordinate positioning, characterized in that: Applied to the receiver of any one of claims 1 to 6, the satellite observation data is satellite single-frequency observation data, and the method comprises: Obtain satellite single-frequency observation data, broadcast ephemeris and correction data for each satellite; For a single satellite, determining the satellite orbit and the satellite clock error of the satellite according to the broadcast ephemeris of the satellite, and correcting the satellite orbit and the satellite clock error of the satellite according to the correction data of the satellite; Determine a pseudorange observation equation and a phase observation equation of the satellite according to the satellite single-frequency observation data of the satellite, the corrected satellite clock error and the corrected satellite orbit; Determine the single-frequency half-sum model carrier observation equation of the satellite based on the single-frequency half-sum model, the pseudo-range observation equation of the satellite and the phase observation equation; The initial coordinates are determined according to a single-frequency half-sum model observation equation group consisting of the single-frequency half-sum model carrier observation equation of each satellite and the pseudo-range observation equation of each satellite.

8. The method for initial antenna coordinate positioning according to claim 7, characterized in that: The correction data is the correction number broadcast based on the PPP-B2b signal of the Beidou-3 satellite navigation system.

9. The method for initial antenna coordinate positioning according to claim 7, characterized in that: The single frequency half-sum model carrier observation equation is: in, is the carrier phase observation value, is the original pseudorange observation value, is the original observed value of the phase, is the distance between the satellite and the antenna phase center, dt r is the receiver clock error, is the satellite clock error, is the phase ambiguity, λ is the wavelength, is the combined pseudorange error of the pseudorange observation noise and the first unmodeled error, is the combined phase error of the phase observation noise and the second unmodeled error, and c is the speed of light.

10. A high-precision positioning and directional camera, characterized in that: The camera includes a receiver, the receiver including a memory, a processor and at least two antennas; The antenna is used to receive satellite observation data, the memory is used to store a computer program, and the processor is used to execute the computer program to implement the method according to any one of claims 1 to 9 based on the satellite observation data.

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