Satellite formation design method and device for tomographic SAR data acquisition

Abstract

The invention discloses a tomographic SAR data acquisition-oriented satellite formation design method and device, and belongs to the technical field of satellite formation design. The method comprises the following steps: determining the minimum sampling number required by chromatography treatment according to design parameters; according to the relationship between the number of satellites and the number of equivalent phase centers which can be generated, determining the optimal number of satellites and transmit-receive mode setting; determining the arrangement of each satellite in the formation according to the chromatography performance; according to the arrangement of the satellites in the formation, the maximum along-orbit baseline and the maximum vertical baseline of the outermost satellite are calculated; calculating formation parameters of the outermost side satellites; determining multi-satellite formation parameters according to a phase center approximation principle and formation geometry to obtain equivalent phase centers distributed at equal intervals; according to the multi-satellite formation parameters, calculating orbit six elements of all satellites in the formation; according to the invention, different atmospheric phases are not introduced in each acquisition, the data acquisition time is shortened, and the data reliability is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of satellite formation design, and in particular relates to a satellite formation design method and device for tomographic SAR data acquisition. Background Art

[0002] Spaceborne tomographic SAR uses satellites as its platform and has global observation capabilities. It can obtain three-dimensional information of large-scale scenes and is of great significance in urban planning, resource statistics, etc. At present, the processing of tomographic SAR usually requires more than 20 images to achieve reliable reconstruction results. However, most tomographic data comes from repeated satellite flights, which takes a long time and introduces deformation information of the ground objects. In addition, different sampling times will also introduce different atmospheric phases. Therefore, it is necessary to add processing steps such as phase error correction, and there are errors in the estimated height. In recent years, scholars at home and abroad have carried out research on using small data sets to realize tomographic processing. Reducing the number of images required for tomographic processing has reduced data acquisition time to a certain extent, but the phase error cannot be removed.

[0003] Satellite formation technology can simultaneously acquire images of the same area from different perspectives and directly provide data with evenly distributed baselines, providing higher quality and faster input for tomographic processing. The development of formation satellites has greatly improved the efficiency and quality of data acquisition, but there is currently no satellite formation solution or design method specifically used for tomographic data acquisition. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a satellite formation design method and device for tomographic SAR data acquisition. The satellite formation designed by the present invention can realize the tomographic data acquisition of the required scene in a single pass, and will not introduce different atmospheric phases in each acquisition, thereby reducing data acquisition time and improving data reliability.

[0005] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0006] A satellite formation design method for tomographic SAR data acquisition includes the following steps:

[0007] Step 1: Determine the minimum number of samples required for chromatography treatment based on design parameters;

[0008] Step 2: Determine the optimal number of satellites and the setting of the transmission and reception mode according to the relationship between the number of satellites and the number of equivalent phase centers that can be generated;

[0009] Step 3: Determine the arrangement of each satellite in the formation according to the tomographic performance;

[0010] Step 4: Calculate the maximum along-track baseline and maximum vertical baseline of the outermost satellite according to the arrangement of the satellites in the formation;

[0011] Step 5, calculating the formation parameters of the outermost satellite;

[0012] Step 6: According to the phase center approximation principle and formation geometry, determine the multi-star formation parameters to obtain equivalent phase centers with equal intervals;

[0013] Step 7: Calculate the six orbital numbers of all satellites in the formation according to the multi-satellite formation parameters.

[0014] On the other hand, the present invention provides a satellite formation design device for tomographic SAR data acquisition, comprising:

[0015] The design parameter analysis unit is used to determine the minimum number of samples required for tomographic processing according to the demand parameters in the design parameters; determine the optimal number of satellites and the setting of the transmission and reception mode, i.e., the formation design parameters in the design parameters, according to the relationship between the number of satellites and the number of equivalent phase centers that can be generated; and determine the arrangement of each satellite in the formation according to the selected basic formation;

[0016] The formation parameter design unit is used to calculate the maximum along-track baseline and maximum vertical baseline of the outermost satellite according to the arrangement of each satellite in the formation; calculate the formation parameters of the outermost satellite; determine the multi-satellite formation parameters according to the phase center approximation principle and formation geometry to obtain equivalent phase centers with equal intervals; calculate the six orbital numbers of all satellites in the formation according to the multi-satellite formation parameters.

[0017] In a third aspect, the present invention provides an electronic device comprising: one or more processors; and a memory for storing one or more programs; wherein, when the one or more programs are executed by the one or more processors, the one or more processors implement the aforementioned satellite formation design method for tomographic SAR data acquisition.

[0018] In a fourth aspect, the present invention provides a computer-readable storage medium having executable instructions stored thereon, which, when executed by a processor, enables the processor to implement the aforementioned satellite formation design method for tomographic SAR data acquisition.

[0019] The beneficial effects of the present invention are:

[0020] The satellite formation design method for tomographic SAR data acquisition provided by the present invention gradually determines the minimum sampling number required for the tomographic processing, the number of satellites and the transmission and reception mode settings, and the satellite arrangement according to the design parameters, calculates the multi-satellite formation parameters, and determines the six orbital numbers of all satellites in the formation; the satellite formation scheme determined by the present invention can generate data with a uniformly distributed baseline using only a single flight, providing higher quality and faster data support for tomographic processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A flow chart of a satellite formation design method for tomographic SAR data acquisition according to the present invention;

[0022] Figure 2 Schematic diagram of the relative motion of the binary star formation represented by the CW equation;

[0023] Figure 3 This is a schematic diagram of a formation scheme with the spiral as the basic formation;

[0024] Figure 4 It is a schematic diagram of a formation scheme using wheels as the basic formation;

[0025] Figure 5 This is a diagram of the formation scheme using the pendulum as the basic formation;

[0026] Figure 6 The simulation results of the formation scheme with spiral as the basic formation within one orbital period, where (a) is the relative position and relative motion trajectory of the satellites, (b) is the relative position and relative motion trajectory of the equivalent phase center, (c) is the vertical baseline of the formation within one orbital period, (d) is the tomographic resolution within one orbital period, and (e) is the unambiguous height within one orbital period. DETAILED DESCRIPTION

[0027] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0028] like Figure 1 As shown, it is a flow chart of a satellite formation design method for tomographic SAR data acquisition of the present invention, which specifically includes:

[0029] Step 1: Determine the minimum number of samples required for chromatography based on the design parameters .

[0030] Design parameters include demand parameters, formation design parameters and other parameters;

[0031] The required parameters refer to the tomographic performance that the designer expects to obtain, which are the number of scattering centers that the tomography is expected to complete unmasking. ; Latitude range of the observation area , The southernmost latitude, is the northernmost latitude; the minimum Rayleigh resolution requirement within the observation area .

[0032] Formation design parameters refer to the formation satellite conditions required or satisfied to achieve the target tomographic performance, which are the total number of satellites in the formation ; Satellites in the formation that have both transmit and receive capabilities, i.e. the number of T&R satellites ; The basic formation configuration chosen by the designer , including three basic formations: Cartwheel, Pendulum and Helix. Among them, the number of satellites with only receiving capability, that is, R satellites, is .

[0033] There are three basic formation configurations, including:

[0034] Cartwheel, Pendulum and Helix. For the basic formation of binary satellites, the classic relative motion model for close-range formation flight of satellites can be used to describe it - the CW equation, which is based on the LVLH coordinate system of the primary satellite. The axis represents the radial direction of the Earth away from the center of the Earth. The axis is the direction of motion of the main star. The axis is perpendicular to the orbital plane. When there is no external force and certain conditions are met, the orbital mechanical energy of the formation satellite is conserved, and the CW equation can be described as:

[0035] ;

[0036] in, , is the orbital period, and the parameter is the relative motion trajectory The semi-minor axis of the projected ellipse in the plane, yes The initial phase angle in the plane, is the relative motion trajectory along The amplitude of the simple harmonic motion in the direction, yes The initial phase of the directional motion, The relative motion center of the auxiliary star and the main star Distance in direction; can use formation parameters Determine the relative motion relationship between the primary and secondary satellites.

[0037] Furthermore, other satellites in the formation and the reference satellite are made to form the basic formation together to form an equivalent phase center distribution with a uniform baseline. Other alternatives may be used, such as combining different basic formations.

[0038] Other parameters are the maximum along-track baseline allowed by the formation , Radar view (left side is considered positive, right side is considered negative) and the six orbital numbers of the reference satellite .

[0039] In the above scheme, the six numbers of the track include: the major semi-axis , eccentricity , orbital inclination , perigee depression angle , right ascension of ascending node Peace Anomaly . You can use the true anomaly angle Instead of the mean anomaly, the subscript Represents the reference satellite.

[0040] According to the design parameters, the minimum number of samples required for the chromatography treatment is determined , including: for areas without obvious deformation and uniform baseline, the number of scattering centers that can be recovered, that is, the number of scattering centers that are expected to be unmasked by the tomography With the minimum number of samples The relationship between them is:

[0041] ;

[0042] That is to say, at least 4 samples are required to separate 2 overlapping scattering centers, and at least 6 samples are required to separate 3 overlapping scattering centers.

[0043] Step 2: Based on the total number of satellites The number of equivalent phase centers that can be generated The relationship between satellites and the receiving and transmitting modes is determined.

[0044] Assume that When there are T&R satellites with the same frequency, the maximum number of equivalent phase centers, which can generate at least non-overlapping equivalent phase centers; when the formation satellites include both T&R satellites and R satellites, the number of equivalent phase centers that can be generated in the formation for:

[0045] ;

[0046] in, For permutation and combination operations, let q=2, p= , this parameter can be written as , which means that regardless of the selection order, Choose from a collection of different items The number of methods per project, is the total number of satellites in the formation, is the number of T&R satellites in the formation, is the number of R satellites in the formation, satisfying . Chromatography treatment needs to meet:

[0047] ;

[0048] When the vertical baselines formed by the equivalent phase centers are equally spaced, “=” holds true.

[0049] The relationship between the number of satellites in the formation and the number of equivalent phase centers that can be generated is shown in Table 1.

[0050] Table 1

[0051] The overlapping equivalent phase centers do not bring any difference in the perspective of the data and are considered to provide the same tomographic information. In order to reduce data waste and save satellite costs, a continuous generation of The formation scheme with two non-overlapping equivalent phase centers is the most cost-effective. This can be achieved using the data set corresponding to the underline in Table 1, so the formation containing two T&R satellites is the object of subsequent design.

[0052] The optimal number of satellites and the setting of the transmission and reception mode include:

[0053] The formation contains two T&R satellites, and the rest are R satellites.

[0054] In the above scheme, the chromatographic performance includes Rayleigh resolution and unambiguous height ; The Rayleigh resolution It is expressed as:

[0055] ;

[0056] in, is the signal wavelength, is the reference image slant distance, is the length of the synthetic aperture in the tomographic direction, i.e., the total span of the vertical baseline; the unambiguous height It is expressed as:

[0057] ;

[0058] in, is the vertical baseline spacing.

[0059] Step 3: Determine the arrangement of satellites in the formation based on the tomographic performance.

[0060] When designing the distribution of satellites, there are a few things to consider:

[0061] While ensuring the tomographic resolution, the equivalent phase center is required to be evenly distributed to minimize the side lobes of the tomographic signal;

[0062] Since there are T&R satellites and R satellites of different sizes and masses, it is more difficult to maintain formation flight due to the different drag, so a symmetrical formation structure is used to reduce drag;

[0063] Signal synchronization is a prerequisite for the normal operation of formation satellites, so the satellites are separated along the main track so that they do not block each other, creating conditions for synchronization.

[0064] Therefore, in order to obtain a formation with a large total baseline length and uniform distribution, the two T&R satellites in the formation need to be placed outside the formation, the formation is symmetrical along the center of the main track, and the satellites are at a certain distance along the main track. The main track is the track formed by the main satellite in a two-satellite formation, and is the track formed by the reference satellite in a multi-satellite formation.

[0065] Step 4: Calculate the maximum along-track baseline and maximum vertical baseline of the outermost satellite according to the formation arrangement.

[0066] The dual-satellite formation relies on the main and auxiliary satellites to form the baseline. In contrast, the multi-satellite formation relies on the two outermost satellites to form the maximum baseline. , Latitude range of the observation area Internal tomography resolution meets the minimum Rayleigh resolution requirement According to the design requirements, the maximum along-track baseline formed by the outermost T&R satellite and the reference satellite along the main track is:

[0067] ;

[0068] The maximum vertical baseline is:

[0069] ;

[0070] in, is the maximum vertical baseline formed by the formation, is the maximum vertical baseline formed by the outermost T&R satellite and the reference satellite. represents a T&R satellite, Indicates a vertical baseline, specifically, without a subscript Indicates the baseline of the formation, with subscript Indicates the baseline formed by the outermost T&R satellite and the reference satellite, with the latter being half of the former.

[0071] Observation Area Center The resolution to be achieved;

[0072] ;

[0073] in, is the latitude range of the sub-satellite point of the reference satellite.

[0074] Step 5: Calculate the formation parameters of the outermost satellite.

[0075] The CW equations mentioned above can represent the relative motion of the binary star formation. Obviously, the relative motion can be decomposed into two independent motions: one in the orbital plane and the other perpendicular to the orbital plane. The former is an ellipse with an eccentricity of 2, and the latter is a simple harmonic motion. The relative motion relationship is as follows: Figure 2 shown.

[0076] You can use formation parameters Determine the relative motion relationship between the main and auxiliary satellites. For the three basic formations, the formation parameters need to meet the corresponding conditions.

[0077] When the wheel formation is selected as the basic formation, the formation parameters of the double star wheels can be set to:

[0078] ;

[0079] When the pendulum formation is selected as the basic formation, the formation parameters of the binary pendulum can be set to:

[0080] ;

[0081] When the spiral formation is selected as the basic formation, the formation parameters of the double star spiral can be set to:

[0082] ;

[0083] in, is an auxiliary parameter, and They represent the maximum vertical baseline and the maximum along-track baseline formed by the main and auxiliary satellites, respectively. is the initial mean anomaly angle of the primary star, is the initial subsatellite latitude of the main star, The latitude range of the sub-star point of the main star, The center of the relative motion trajectory of the auxiliary star in the spiral formation and the main star The distance between the axes. It is worth noting that However, the baseline along the track can also be set by When a multi-satellite formation is used, the main satellite in the above formula becomes the reference satellite, and the relative motion relationship between all satellites in the formation and the main satellite can be expressed using different formation parameters. calculate.

[0084] According to the basic formation selected by the designer , the above corresponding formula is used to calculate the formation parameters of the outermost satellite and the reference satellite, which is .

[0085] Step 6: Determine the multi-star formation parameters based on the phase center approximation principle and formation geometry to obtain equivalent phase centers with equal intervals, that is, a uniformly distributed baseline. This includes:

[0086] According to the phase center approximation principle, the transmitter and receiver that are not on the same platform are equivalent to the same transmitting and receiving platform at the center position, and then the formation geometry is used to determine the multi-satellite formation parameters to obtain equivalent phase centers with equal intervals, that is, a uniformly distributed baseline.

[0087] Multi-satellite formations require calculation of formation parameters between each satellite in the formation and the reference satellite , , that is, the formation parameters of the entire formation :

[0088] ;

[0089] Each row represents the formation parameter of a satellite, and each column represents a formation parameter of all satellites in the formation.

[0090] The T&R satellite that has calculated the basic formation parameters is selected as the benchmark, that is, the first satellite. In order to obtain a uniformly distributed baseline, the projection of the equivalent phase center position on the cross-track plane must be on a straight line, and the same applies to the satellites. The remaining satellites are arranged in order of distance from the benchmark satellite: , satellites, and its formation parameters are .

[0091] definition Vector Represents the satellite distribution in the cross-orbit plane, each element is:

[0092] ;

[0093] in, The symbol indicates the The lateral position relationship of a satellite relative to the main track. A positive value indicates that the satellite is on the same side of the main track as the reference satellite, a negative value indicates that the satellite is on the opposite side, and 0 indicates that it is on the main track. Indicates the relative distance between the satellite and the main track, the reference satellite is 1. Symbol function Defined as:

[0094] ;

[0095] Different basic formations are used, and the subsequent multi-star formation parameters are determined in different ways. When a more complex spiral is used as the basic formation, the multi-star formation parameters are calculated in the following way:

[0096] In the CW equation, the y-axis is the direction of the satellite's main track. The effective baseline formed by the satellite and the main track is in the intersection plane and is related to the formation parameters A and B. A and B change in the same proportion to ensure that the baseline remains evenly distributed, that is, the equivalent phase centers are evenly spaced, and the ratio is defined as:

[0097] ;

[0098] ;

[0099] in, , Indicates the first The ratio of each formation parameter of the satellites to the corresponding parameter of the reference satellite satisfies . Define the ratio:

[0100] ;

[0101] Indicates the first Satellite formation parameters Formation parameters with reference satellite ratio.

[0102] Can form a new vector , specifically:

[0103] ;

[0104] vector Represents the formation parameters of all satellites in the formation and the reference satellite The ratio of one element is always 1, which means that this satellite is the reference satellite. Similarly, for the formation parameter and , we can define the ratio and .

[0105] Formation parameter representing the angle and It can be calculated as:

[0106] ;

[0107] ;

[0108] Also form a new vector and , specifically:

[0109] ;

[0110] ;

[0111] Therefore, the complete formation parameters with spiral as the basic formation are:

[0112] ;

[0113] in, is the Hadamard product, subscript represents the parameters of the multi-star formation with spiral as the basic formation. The schematic diagram of the layered formation scheme designed with spiral as the basic formation is shown in Figure 3 .

[0114] When the wheel is selected as the basic formation, the parameters of the multi-star formation need to be determined based on the formation parameters of the wheel. and All are 0. At this time, the satellite moves along the x-axis in the cross-orbit plane. Define the formation parameters of all satellites The vectors are:

[0115] ;

[0116] Formation parameters It can still be determined by the following formula:

[0117] ;

[0118] And the vector composed of other parameters , and are all zero vectors. The parameters of the entire formation with wheels as the basic formation are:

[0119] ;

[0120] Subscript represents the parameters of the multi-satellite formation with the wheel as the basic formation. The schematic diagram of the layered formation scheme designed with the pendulum as the basic formation is shown in Figure 4 .

[0121] When the pendulum is used as the basic formation, the parameters of the multi-star formation need to be determined according to the formation parameters of the pendulum. and All are 0. Define the formation parameters of all satellites The vectors are:

[0122] ;

[0123] Since the satellites are moving along the z-axis in the cross-orbit plane, it is necessary to separate the satellites along the main trajectory and calculate for:

[0124] ;

[0125] The column vector is . Formation parameters It can still be determined by the following formula:

[0126] ;

[0127] And the vector composed of other parameters and are all zero vectors. The parameters of the entire formation with the pendulum as the basic formation are:

[0128] ;

[0129] Subscript represents the parameters of the multi-star formation with the pendulum as the basic formation. The schematic diagram of the layered formation scheme designed with the pendulum as the basic formation is shown in Figure 5 .

[0130] Step 7, calculate the six orbital numbers of all satellites in the formation according to the multi-satellite formation parameters.

[0131] Satellite orbits can be described by orbital elements, which are the major and minor axes. , eccentricity , orbital inclination , perigee depression angle , right ascension of ascending node Peace Anomaly (True Anomaly ). The orbital element difference between the main and auxiliary satellites can be used To describe the relative motion, use the following formula to calculate:

[0132] ;

[0133] This can be done based on the formation configuration parameters To calculate the orbital root difference :

[0134] ;

[0135] By adding the calculated orbital element difference to the six orbital element numbers of the reference satellite entered by the designer, the six orbital element numbers of all satellites in the formation can be obtained.

[0136] Example

[0137] The spiral is selected as the basic formation, and five satellites are used for formation. The tomographic Rayleigh resolution is required to be no more than 20m within the latitude range of S40°~N60°. The simulation results are as follows: Figure 6 As shown, (a) is the relative position and relative motion trajectory of the satellites, (b) is the relative position and relative motion trajectory of the equivalent phase center, (c) is the vertical baseline of the formation within one orbital period, (d) is the tomographic resolution within one orbital period, and (e) is the unambiguous height within one orbital period. It can be seen that the formation designed by the design method of the present invention meets the resolution requirements.

[0138] On the other hand, the present invention provides a satellite formation design device for tomographic SAR data acquisition, wherein each unit included in the device can implement each step of the aforementioned method, specifically including:

[0139] The design parameter analysis unit is used to determine the minimum number of samples required for tomographic processing according to the demand parameters in the design parameters; determine the optimal number of satellites and the setting of the transmission and reception mode, i.e., the formation design parameters in the design parameters, according to the relationship between the number of satellites and the number of equivalent phase centers that can be generated; and determine the arrangement of each satellite in the formation according to the selected basic formation;

[0140] The formation parameter design unit is used to calculate the maximum along-track baseline and the maximum vertical baseline of the outermost satellite according to the arrangement of each satellite in the formation; calculate the formation parameters of the outermost satellite; determine the multi-satellite formation parameters according to the phase center approximation principle and formation geometry to obtain equivalent phase centers with equal intervals; calculate the six orbital numbers of all satellites in the formation according to the multi-satellite formation parameters;

[0141] Furthermore, it can also include a formation analysis unit for visualizing the designed formation, displaying the distribution of satellites in the formation, and displaying the distribution of equivalent phase centers formed by the formation; verifying whether the designed formation meets the design requirements, specifically, whether the tomographic capability of the formation in the observation area is higher than the minimum Rayleigh resolution requirement, and whether the number of non-overlapping equivalent phase centers generated in the observation area meets the tomographic de-masking capability requirements of the formation.

[0142] In a third aspect, the present invention provides an electronic device comprising: one or more processors; and a memory for storing one or more programs; wherein, when the one or more programs are executed by the one or more processors, the one or more processors implement the aforementioned satellite formation design method for tomographic SAR data acquisition.

[0143] In a fourth aspect, the present invention provides a computer-readable storage medium having executable instructions stored thereon, which, when executed by a processor, enables the processor to implement the aforementioned satellite formation design method for tomographic SAR data acquisition.

[0144] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A satellite formation design method for tomographic SAR data acquisition, characterized in that: The steps include: Step 1: Determine the minimum number of samples required for chromatography treatment based on design parameters; Step 2: Determine the optimal number of satellites and the setting of the transmission and reception mode according to the relationship between the number of satellites and the number of equivalent phase centers that can be generated; Step 3: Determine the arrangement of each satellite in the formation according to the tomographic performance; Step 4: Calculate the maximum along-track baseline and maximum vertical baseline of the outermost satellite according to the arrangement of the satellites in the formation; Step 5, calculating the formation parameters of the outermost satellite; Step 6: According to the phase center approximation principle and formation geometry, determine the multi-star formation parameters to obtain equivalent phase centers with equal intervals; Step 7: Calculate the six orbital numbers of all satellites in the formation according to the multi-satellite formation parameters.

2. The satellite formation design method for tomographic SAR data acquisition according to claim 1, characterized in that: The step 1 comprises: Determine the design parameters required for a satellite formation for tomographic SAR data acquisition, the design parameters including demand parameters, formation design parameters and other parameters. The demand parameters refer to the tomographic performance expected by the designer, which are the number of scattering centers for tomographic de-masking, the latitude range of the observation area and the minimum Rayleigh resolution requirement in the observation area; the formation design parameters refer to the formation satellite conditions required or satisfied to achieve the target tomographic performance, which are the total number of satellites in the formation, the number of satellites in the formation with simultaneous transceiver capabilities and the basic formation configuration selected by the designer; the other parameters are the maximum along-track baseline allowed by the formation, the radar under-angle view and the six orbital numbers of the reference satellite.

3. The satellite formation design method for tomographic SAR data acquisition according to claim 2, characterized in that: The optimal number of satellites and the transmission and reception mode are determined in step 2 as follows: two satellites in the formation are satellites with both transmission and reception capabilities, namely, T&R satellites, and the remaining satellites are satellites with only reception capabilities, namely, R satellites.

4. The satellite formation design method for tomographic SAR data acquisition according to claim 3, characterized in that: The step 3 comprises: According to the performance indicators of tomographic SAR processing, namely, Rayleigh resolution and unambiguous height, the arrangement of the satellites in the formation is determined as follows: the two T&R satellites are placed on the outside of the formation, the formation is symmetrical along the center of the main trajectory, and the satellites are at a preset distance along the main trajectory; the main trajectory is the trajectory formed by the main star in a binary star formation, and is the trajectory formed by the reference satellite in a multi-star formation.

5. The satellite formation design method for tomographic SAR data acquisition according to claim 4, characterized in that: The step 4 comprises: The multi-satellite formation relies on the two outermost T&R satellites to form the maximum along-track baseline and the maximum vertical baseline. The maximum along-track baseline formed by the outermost T&R satellite and the reference satellite on the main track is half of the maximum along-track baseline allowed by the formation input by the designer. The maximum vertical baseline is half of the vertical baseline calculated using the Rayleigh resolution.

6. The satellite formation design method for tomographic SAR data acquisition according to claim 5, characterized in that: The step 5 comprises: According to the basic formation selected by the designer, the formation parameters of the binary satellite relationship formed by any outermost T&R satellite in the basic formation and the reference satellite are calculated, wherein the basic formation is one of a spiral, a wheel and a pendulum.

7. The satellite formation design method for tomographic SAR data acquisition according to claim 6, characterized in that: The step 6 comprises: According to the phase center approximation principle, the transmitter and receiver that are not on the same platform are equivalent to the same transmitting and receiving platform at the center position, and then the formation geometry is used to determine the multi-satellite formation parameters to obtain equivalent phase centers with equal intervals, that is, a uniformly distributed baseline.

8. The satellite formation design method for tomographic SAR data acquisition according to claim 7, characterized in that: The step 7 comprises: According to the multi-satellite formation parameters, the difference in the number of orbital elements between each satellite in the formation and the reference satellite is calculated, and then the difference is added to the six orbital elements of the reference satellite to calculate the six orbital elements of all satellites in the formation.

9. A satellite formation design device for tomographic SAR data acquisition, characterized in that: include: A design parameter analysis unit, used to determine the minimum number of samples required for chromatography processing according to the demand parameters in the design parameters; According to the relationship between the number of satellites and the number of equivalent phase centers that can be generated, the optimal number of satellites and the setting of the transmission and reception mode, i.e., the formation design parameters in the design parameters, are determined; according to the selected basic formation, the arrangement of each satellite in the formation is determined; A formation parameter design unit, used to calculate the maximum along-track baseline and the maximum vertical baseline of the outermost satellite according to the arrangement of the satellites in the formation; And calculate its formation parameters; According to the phase center approximation principle and formation geometry, the multi-satellite formation parameters are determined to obtain equivalent phase centers with equal intervals. According to the multi-satellite formation parameters, the six orbital numbers of all satellites in the formation are calculated.

10. An electronic device, characterized in that: include: one or more processors; A memory for storing one or more programs; Wherein, when one or more programs are executed by the one or more processors, the one or more processors implement the satellite formation design method for tomographic SAR data acquisition as described in any one of claims 1-8.

11. A computer-readable storage medium, characterized in that: Executable instructions are stored thereon, and when the instructions are executed by the processor, the processor can implement the satellite formation design method for tomographic SAR data acquisition as described in any one of claims 1-8.

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