A method and system for designing InSAR baseline combination for four-satellite formation

Abstract

The present invention provides an InSAR baseline combination design method and system for a four-star formation, belonging to the field of radar measurement technology, including: according to the surveying and mapping scale requirements and the InSAR multi-baseline fusion elevation measurement error requirements, given the formation SAR satellite imaging parameters, calculate the satellite vertical baseline initial constraint range; calculate the interferometric stereo measurement offset fusion standard deviation of each baseline; calculate the interferometric stereo measurement fusion offset error scaling coefficient and dimension conversion coefficient, and then calculate the interferometric stereo measurement fusion phase standard deviation; construct unambiguous elevation reconstruction constraint conditions; according to system parameters, combined with the given constraint condition set, solve the baseline combination threshold range, and obtain the InSAR baseline design combination of the four-star formation. The present invention is used for the design optimization of the formation orbit.

Description

Technical Field

[0001] The invention belongs to the field of radar measurement technology, and in particular relates to an InSAR baseline combination design method and system for a four-star formation. Background Art

[0002] Interferometric Synthetic Aperture Radar (InSAR) is a radar technology that uses microwaves for mapping. Currently, bistatic spaceborne InSAR systems have been widely used in the generation of digital elevation models, such as the production of TanDEM-X global 90-meter grid and 30-meter grid resolution topographic mapping products. With the continuous improvement of measurement accuracy requirements, the disadvantage of bistatic mapping in the contradiction between baseline length and phase reconstruction has gradually emerged, and multi-base systems have begun to become a research hotspot. Multi-base systems can improve the accuracy and stability of topographic measurements by providing multiple observation baselines. However, how to design the optimal baseline combination in a multi-base system to achieve high-precision elevation measurement is still a problem that needs to be solved.

[0003] In the case of multiple baselines, the selection of baseline length and baseline inclination becomes more complicated, and different baseline combinations will have different effects on the system error. Therefore, a systematic method is needed to guide the baseline design in the multi-baseline system to meet the requirements of high-precision measurement tasks. At present, the more mature multi-baseline phase unwrapping scheme adopts the method of "long and short baselines" to construct differential interferograms, requiring the baseline design ratio to be close to 2:3, and the constraints on the baseline are relatively strict; while the multi-baseline phase reconstruction method based on phase gradient cannot guarantee the robustness of phase reconstruction in global terrain mapping. At present, in the TanDEM-X dual-satellite terrain mapping mission, interferometric stereo measurement technology (InterferometricStereo-Radargrammetry) is introduced, which can realize robust mapping product generation and product quality detection. However, the current "long and short baseline" mapping method cannot achieve robust point-to-point phase reconstruction. When the number of formation satellites increases from 2 to 4, the interferometric stereo measurement method can be used for phase reconstruction, but there is no accurate analysis and evaluation method for the requirements and impact of baseline design. If the baseline design is carried out according to the existing "long and short baseline" surveying method, it will lead to problems such as difficulty in baseline design and a low proportion of available data in the baseline combination.

[0004] In summary, the current multi-baseline InSAR baseline combination design method cannot effectively utilize the advantages brought by multi-baseline satellites. It is urgent to study new multi-baseline combination design methods to make full use of multi-baseline information to reduce baseline constraints and effectively reduce the difficulty of multi-baseline formation orbit design while ensuring the resolution and accuracy of elevation measurement. Summary of the invention

[0005] In order to solve the above technical problems, the present invention proposes an InSAR baseline combination design method and system for a four-satellite formation to reduce the complexity of subsequent formation orbit design.

[0006] In order to achieve the above object, the present invention adopts the following technical scheme:

[0007] A method for designing an InSAR baseline combination for a four-satellite formation includes the following steps:

[0008] Step 1: Calculate the initial constraint range of the satellite vertical baseline according to the SAR satellite imaging parameters, surveying and mapping scale requirements and InSAR multi-baseline fusion height measurement error requirements;

[0009] Step 2, calculating the standard deviation of the multi-baseline interferometric stereo measurement offset fusion result;

[0010] Step 3, calculating the error scaling coefficient and dimension conversion coefficient of the interferometric stereo measurement fusion offset, and then calculating the interferometric stereo measurement fusion phase standard deviation;

[0011] Step 4: Construct unambiguous elevation reconstruction constraints;

[0012] Step 5: Combine the initial constraint range of the satellite vertical baseline in step 1 and the unambiguous elevation reconstruction constraint in step 4 to solve the baseline combination threshold range and realize the InSAR baseline combination design of the four-satellite formation.

[0013] The present invention also provides an InSAR baseline combination design system for a four-satellite formation, comprising the following modules:

[0014] The initial constraint range calculation module calculates the initial constraint range of the satellite vertical baseline according to the SAR satellite imaging parameters, surveying and mapping scale requirements and InSAR multi-baseline fusion height measurement error requirements;

[0015] The fusion result standard deviation calculation module calculates the standard deviation of the multi-baseline interferometric stereo measurement offset fusion result;

[0016] The interferometric stereo measurement fusion phase standard deviation calculation module calculates the error scaling coefficient and dimension conversion coefficient of the interferometric stereo measurement fusion offset, and then calculates the interferometric stereo measurement fusion phase standard deviation;

[0017] Constraint construction module, constructs unambiguous elevation reconstruction constraints;

[0018] The solution module combines the initial constraint range of the satellite vertical baseline and the constraint conditions of unambiguous elevation reconstruction to solve the baseline combination threshold range and realize the InSAR baseline design of the four-satellite formation.

[0019] The present invention also provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the steps of the above-mentioned InSAR baseline combination design method for a four-star formation are implemented.

[0020] The present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the above-mentioned InSAR baseline combination design method for a four-star formation.

[0021] Beneficial effects:

[0022] The present invention realizes the InSAR baseline combination design in the case of four-satellite formation, introduces the interferometric stereo measurement offset as the baseline design constraint in the InSAR phase reconstruction process, and reduces the constraint of baseline design under the premise of ensuring the accuracy of elevation measurement and elevation phase reconstruction, so that the range of effective baseline selection is larger. The present invention can reduce the complexity of subsequent formation orbit design. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A flowchart of an InSAR baseline combination design method for a four-satellite formation according to the present invention;

[0024] Figure 2 A plot of the vertical baseline variation within one orbital period for a four-satellite formation system design case. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0026] In the description of the present invention, it should be understood that the terms "upper", "lower", "top", "bottom", "inner", "outer", etc. used in the present invention to indicate the orientation or position relationship is based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0027] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0028] like Figure 1 As shown, the present invention proposes an InSAR baseline combination design method for a four-satellite formation, comprising the following steps:

[0029] Step 1: According to the ground resolution in the satellite design parameters and the scale resolution of the surveying and mapping products to be generated (i.e. Figure 1 The formation SAR satellite imaging parameters and mapping scale in the SAR satellite formation are set as , the multi-view number in the distance direction is The mission stipulates that the standard deviation of InSAR multi-baseline fusion height measurement is (Right now Figure 1 InSAR multi-baseline fusion height measurement error in the formation), under the given formation SAR satellite imaging parameters, the initial constraint conditions of the satellite vertical baseline are determined. The calculation method of the initial constraint conditions of the satellite vertical baseline is (i.e. Figure 1 Step 1: Calculate the initial constraint range of WeChat vertical baseline):

[0030] (1)

[0031] in, The elevation conversion coefficient vector representing the interference phase, represents the information matrix of the interference phase, and the superscript T represents the matrix transpose. Represents matrix inversion.

[0032] Interference phase elevation conversion coefficient vector The calculation formula is:

[0033] (2)

[0034] in, π is the circumference of a circle, is the radar carrier frequency, is the speed of light in vacuum, is the slant range to the target, For the lower perspective, is the vertical baseline length. For a four-star formation InSAR system, each acquisition includes A image, B image, C image, and D image, which are four images collected by A star, B star, C star, and D star, respectively. Therefore The first letter added after the subscript indicates the primary interference image, and the second letter indicates the secondary interference image. For example, It indicates the vertical baseline length for interferometry of the images acquired by stars A and B.

[0035] Information matrix of interferometric phase It is expressed as:

[0036] (3)

[0037] in, For multiple views, , is the coherence coefficient matrix, represents the Hadamard product, is the coherence coefficient matrix Identity matrices of the same dimensions.

[0038] Coherence Coefficient Matrix is defined as:

[0039] (4)

[0040] in, is the coherence coefficient of the interference pattern, The first letter in the subscript indicates the main interferometric image, and the second letter indicates the auxiliary interferometric image. For a four-star formation InSAR, each acquisition consists of A image, B image, C image, and D image. For example, This indicates the coherence coefficient of interference between image A as the main image and image B as the auxiliary image.

[0041] According to the definition of coherence coefficient, the coherence coefficient of the interference pattern is It is expressed as:

[0042] (5)

[0043] in, is the noise sensitivity decorrelation coefficient, is the azimuth Doppler decorrelation coefficient, is the distance to baseline decorrelation coefficient, is the quantization noise decorrelation coefficient, is the fuzzy decorrelation coefficient, is the volume scattering decoherence coefficient.

[0044] Noise sensitivity decorrelation coefficient , azimuth Doppler decorrelation coefficient , fuzzy decorrelation coefficient and quantization noise decorrelation coefficient The distance to baseline decorrelation coefficient is given by the radar system parameter design. , volume scattering decoherence coefficient Related to the baseline design, the distance to the baseline decorrelation coefficient The calculation expression is:

[0045] (6)

[0046] in, is the critical baseline. For different combinations of interference patterns in the four-star formation, Can be , , , , or . Critical Baseline The expression is:

[0047] (7)

[0048] in, is the radar bandwidth, is the slant range to the target, is the wavelength of radar electromagnetic wave, For the lower perspective, is the speed of light in a vacuum.

[0049] Volume scattering decoherence coefficient The calculation expression is:

[0050] (8)

[0051] in, represents an exponential function with the natural constant e as the base, represents an imaginary number, and there is , is the fuzzy height, is the height, Indicates height The differential symbol of Indicates the vegetation height, Indicates from 0 to Perform definite integral, Indicates the height The vertical scattering profile at time is expressed as:

[0052] (9)

[0053] in, is the one-way amplitude extinction coefficient.

[0054] Blur Height The expression is:

[0055] (10)

[0056] Step 2: Calculate the offset fusion result of multi-baseline interferometric stereo measurement Standard Deviation (Right now Figure 1 Step 2 in : Calculate the standard deviation of the multi-baseline interferometric stereo measurement fusion offset), the calculation method is:

[0057] (11)

[0058] in, represents the interferometric stereo measurement offset information matrix, Represents the interferometric stereo measurement offset conversion coefficient vector.

[0059] Interferometric Stereo Measurement Offset Information Matrix The calculation method is:

[0060] (12)

[0061] in, Represents the number of samples used in the interferometric stereo estimation.

[0062] The interferometric stereo measurement results of each baseline are mapped to the reference baseline and then fused. The vertical baseline length of the reference baseline is Interferometric stereo measurement offset conversion coefficient vector The calculation method is:

[0063] (13)

[0064] Taking AB as the reference baseline, .

[0065] Step 3: Calculate the error scaling factor and dimensional conversion factor , calculate the phase standard deviation of interferometric stereo measurement In the interference combination, the interference pair with the longest vertical baseline is , the interference pair with the shortest vertical baseline is s, and the longest vertical baseline in the interference pair is defined as With the shortest vertical baseline , the unit of vertical baseline is meter (m). The corresponding blur height is , baseline The corresponding blur height is Similarly, the reference baseline The corresponding blur height is (Right now Figure 1 Step 3 in : Calculate the error scaling factor and dimension conversion factor of the interferometric stereo measurement fusion offset, and then calculate the interferometric stereo measurement fusion phase standard deviation).

[0066] To reconstruct the shortest baseline interferogram, the interferometric stereo measurement fusion result needs to be converted from the reference baseline to the shortest baseline s and the error scaling factor needs to be calculated. , the calculation method is:

[0067] (14)

[0068] The offset fusion results of multi-baseline interferometric stereo measurement are Conversion to interferometric stereo measurement phase Conversion factor , the calculation method is:

[0069] (15)

[0070] Then, the interferometric stereo phase standard deviation mapped on the shortest baseline is calculated , the calculation method is:

[0071] (16)

[0072] Step 4: Construct unambiguous elevation reconstruction constraints.

[0073] Constraint 1: It is required that the interferometric stereo measurement phase mapped on the shortest baseline s is three times the standard deviation (i.e. ) and the interference phase of the shortest interference pair s with a vertical baseline of 3 times the standard deviation (i.e. ) is less than or equal to π , the constraints are expressed as:

[0074] (17)

[0075] Among them, the interferometric stereo measurement phase mapped on the interferometric pair s with the shortest vertical baseline is The calculation method is:

[0076] (18)

[0077] in, is the interference coherence coefficient of the interference pair with the shortest vertical baseline.

[0078] Constraint 2: The four-star formation InSAR can achieve six sets of interferograms. Among the six sets of interferograms, the phase noise of the interferogram with the shortest vertical baseline must be 3 times the standard deviation (i.e. ) multiplied by the proportionality factor After that, the result is less than or equal to π , the constraint calculation method is expressed as:

[0079] (19)

[0080] in, represents the vertical baseline length of the longest interferometer pair of vertical baselines, Indicates the vertical baseline length of the shortest interfering pair of vertical baselines.

[0081] Step 5: Combine the given set of constraints, i.e., formula (1), formula (17), and formula (19), to solve the baseline combination threshold range and design the InSAR baseline combination of the four-star formation for the design optimization of the formation orbit.

[0082] The technical solution of the present invention is further described in detail below in conjunction with specific embodiments.

[0083] Example:

[0084] At present, multi-satellite formation (number of satellites ≥ 3) interferometric measurement has become a hot topic in the field of satellite-borne SAR research and application. Among them, the four-satellite formation has become the preferred system configuration for multiple baselines because of its controllable formation control and collaborative imaging complexity. The world's first X-band interferometric synthetic aperture radar earth observation system using four satellites in formation is also in orbit. It adopts an internationally pioneering wheeled formation structure, which is mainly used for topographic survey tasks. It can cover a large area of ​​surveying and mapping areas and generate high-precision digital elevation models. It has a wide range of application value in infrastructure planning, natural resource management and environmental protection, especially in complex terrain conditions such as mountainous areas and forests. In addition, it also has millimeter-level deformation monitoring capabilities, which can provide important data support for the investigation and prevention of geological disasters such as ground subsidence, collapse and landslides, and play a key role in the early identification of potential major geological disasters, becoming an important data basis for applications in multiple fields. The scale of the topographic mapping product of the formation satellite group is set to 1:25000, the standard deviation of elevation measurement is 2 m, and after inputting the radar system parameters, the four-star formation combination with a vertical baseline length combination of 235.9 m, 283.5 m, -47.6 m, 424.2 m, -188.3 m and 140.7 m is evaluated, which meets the accuracy measurement conditions. , and satisfies and The unambiguous elevation reconstruction constraint condition is then used as the surveying constraint condition for satellite formation design. After the formation orbit is designed, the vertical baseline changes of the above four-satellite formation satellites within one orbital period are as follows: Figure 2 as shown). Figure 2 In the figure, the first baseline represents the vertical baseline between stars A and B, the second baseline represents the vertical baseline between stars A and C, the third baseline represents the vertical baseline between stars A and D, the fourth baseline represents the vertical baseline between stars B and C, the fifth baseline represents the vertical baseline between stars B and D, and the sixth baseline represents the vertical baseline between stars C and D.

[0085] The present invention also provides an InSAR baseline combination design system for a four-satellite formation, comprising the following modules:

[0086] The initial constraint range calculation module calculates the initial constraint range of the satellite vertical baseline according to the SAR satellite imaging parameters, surveying and mapping scale requirements and InSAR multi-baseline fusion height measurement error requirements;

[0087] The fusion result standard deviation calculation module calculates the standard deviation of the multi-baseline interferometric stereo measurement offset fusion result;

[0088] The interferometric stereo measurement fusion phase standard deviation calculation module calculates the error scaling coefficient and dimension conversion coefficient of the interferometric stereo measurement fusion offset, and then calculates the interferometric stereo measurement fusion phase standard deviation;

[0089] Constraint construction module, constructs unambiguous elevation reconstruction constraints;

[0090] The solution module combines the initial constraint range of the satellite vertical baseline and the constraint conditions of unambiguous elevation reconstruction to solve the baseline combination threshold range and realize the InSAR baseline design of the four-satellite formation.

[0091] The present invention also provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the above-mentioned InSAR baseline combination design method and steps for a four-star formation are implemented.

[0092] The present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the above-mentioned InSAR baseline combination design method for a four-star formation.

[0093] It should be understood by those skilled in the art that the embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program codes. The solutions in the embodiments of the present invention may be implemented in various computer languages, for example, object-oriented programming language Java and interpreted scripting language JavaScript, etc.

[0094] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0095] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0096] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0097] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0098] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A method for designing InSAR baseline combinations for a four-satellite formation, characterized in that: The steps include: Step 1: Calculate the initial constraint range of the satellite vertical baseline according to the SAR satellite imaging parameters, surveying and mapping scale requirements and InSAR multi-baseline fusion height measurement error requirements; Step 2, calculating the standard deviation of the multi-baseline interferometric stereo measurement offset fusion result; Step 3, calculating the error scaling coefficient and dimension conversion coefficient of the interferometric stereo measurement fusion offset, and then multiplying it by the standard deviation of the multi-baseline interferometric stereo measurement offset fusion result in step 2 to calculate the interferometric stereo measurement fusion phase standard deviation; Step 4: Use the interferometric stereo measurement in step 3 to fuse the phase standard deviation to construct unambiguous elevation reconstruction constraints. The constraints are: Combined with the initial constraint range of the satellite vertical baseline calculated in step 1, the sum of three times the standard deviation of the interferometric stereo measurement fusion phase mapped on the interferometric pair with the shortest vertical baseline and three times the standard deviation of the interferometric phase of the interferometric pair with the shortest vertical baseline is less than or equal to π; The four-star formation InSAR has six sets of interferograms. Among the six sets of interferograms, the three times standard deviation of the phase noise of the interferogram with the shortest vertical baseline multiplied by the ratio coefficient of the longest vertical baseline to the shortest vertical baseline length is less than or equal to π, thereby constructing the constraint condition of unambiguous elevation reconstruction; Step 5: Combine the initial constraint range of the satellite vertical baseline in step 1 and the unambiguous elevation reconstruction constraint in step 4 to solve the baseline combination threshold range and realize the InSAR baseline combination design of the four-satellite formation.

2. The InSAR baseline combination design method for a four-satellite formation according to claim 1, characterized in that: The step 1 comprises: According to the ground resolution in the satellite design parameters and the scale resolution of the surveying and mapping products to be generated, the multi-look numbers of the InSAR data in the azimuth and range directions are set; the standard deviation of the InSAR multi-baseline fusion elevation is calculated using the information matrix of the interference phase and the elevation conversion coefficient vector, and the constraint equation is established according to the accuracy requirements; the initial constraint range of the satellite vertical baseline is solved using the given formation SAR satellite imaging parameters.

3. The InSAR baseline combination design method for a four-satellite formation according to claim 1, characterized in that: The step 2 comprises: Considering the influence of interferometric stereo measurement technology on phase reconstruction, the interferometric stereo measurement offset information matrix and the interferometric stereo measurement offset conversion coefficient vector are calculated, and then the standard deviation of the multi-baseline interferometric stereo measurement fusion offset is calculated.

4. The InSAR baseline combination design method for a four-satellite formation according to claim 1, characterized in that: The step 3 comprises: According to the parameters of the input SAR system, the error scaling coefficient and dimension conversion coefficient of the interferometric stereo measurement fusion offset are calculated, and the standard deviation of the multi-baseline interferometric stereo measurement fusion offset is converted into the standard deviation of the interferometric stereo measurement fusion phase.

5. The InSAR baseline combination design method for a four-satellite formation according to claim 1, characterized in that: In step 5, the InSAR baseline combination design of the four-satellite formation is used for design optimization of the formation orbit.

6. An InSAR baseline combination design system for a four-star formation, characterized in that: Includes the following modules: The initial constraint range calculation module calculates the initial constraint range of the satellite vertical baseline according to the SAR satellite imaging parameters, surveying and mapping scale requirements and InSAR multi-baseline fusion height measurement error requirements; The fusion result standard deviation calculation module calculates the standard deviation of the multi-baseline interferometric stereo measurement offset fusion result; The interferometric stereo measurement fusion phase standard deviation calculation module calculates the error scaling coefficient and dimension conversion coefficient of the interferometric stereo measurement fusion offset, and then multiplies it by the standard deviation of the multi-baseline interferometric stereo measurement offset fusion result to calculate the interferometric stereo measurement fusion phase standard deviation; The constraint condition construction module uses interferometric stereo measurement to fuse the phase standard deviation to construct unambiguous elevation reconstruction constraints. The constraints are: Combined with the initial constraint range of the satellite vertical baseline, the sum of three times the standard deviation of the interferometric stereo measurement fusion phase mapped on the interferometric pair with the shortest vertical baseline and three times the standard deviation of the interferometric phase of the interferometric pair with the shortest vertical baseline is less than or equal to π; The four-star formation InSAR has six sets of interferograms. Among the six sets of interferograms, the three times standard deviation of the phase noise of the interferogram with the shortest vertical baseline multiplied by the ratio coefficient of the longest vertical baseline to the shortest vertical baseline length is less than or equal to π, thereby constructing the constraint condition of unambiguous elevation reconstruction; The solution module combines the initial constraint range of the satellite vertical baseline and the constraint conditions of unambiguous elevation reconstruction to solve the baseline combination threshold range and realize the InSAR baseline design of the four-satellite formation.

7. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the program, the steps of the InSAR baseline combination design method for a four-star formation described in any one of claims 1 to 5 are implemented.

8. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the InSAR baseline combination design method for a four-satellite formation described in any one of claims 1 to 5 are implemented.

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