Distributed satellite orbit simulation method for two-dimensional sea surface flow field inversion

Abstract

The application discloses a kind of distributed satellite orbit simulation methods for two-dimensional sea surface flow field inversion, it is related to distributed SAR system technical field, including: obtaining the initial parameters of the orbit of main satellite, and the initial parameters of the orbit of main satellite are obtained according to the initial parameters of the orbit of main satellite The orbit parameters of main satellite;The true anomaly in the orbit parameters of main satellite is adjusted, and the orbit parameters of first auxiliary satellite and the orbit parameters of second auxiliary satellite are obtained;Wherein, the baseline of main satellite, first auxiliary satellite and second auxiliary satellite satisfies the value range of along-track baseline;According to the demand of task, the orbit parameters of main satellite, first auxiliary satellite and second auxiliary satellite are fixed, the orbit parameters of mobile satellite are obtained, to determine the orbit parameters of distributed satellite.The present application can provide flexible multi-baseline, lay the foundation for high-precision sea surface environment monitoring.

Description

Technical Field

[0001] This invention belongs to the field of distributed SAR system technology, specifically relating to a distributed satellite orbit simulation method for two-dimensional sea surface flow field inversion. Background Technology

[0002] Current global sea surface flow field measurements are mainly based on the fusion of multiple sensors, including spaceborne altimeters, scatterometers, and synthetic aperture radar (SAR), forming a basic database of global flow fields with relatively low resolution. Among these, spaceborne SAR inversion of sea surface flow fields has advantages such as all-day, all-weather, and high spatial resolution. It can take advantage of different bands, polarizations, perspectives, and resolutions, making it more suitable for sea surface feature observation and information inversion.

[0003] In existing technologies, traditional SAR satellites are limited by their platform, with a single and fixed baseline, which cannot meet the high-precision observation requirements under complex and variable sea conditions. At the same time, they can only acquire the sea surface flow field in the line of sight of the radar beam, and cannot acquire the two-dimensional spatial flow field of the sea surface, resulting in insufficient spatial dimension of sea surface flow field measurement and inability to accurately invert the energy interaction process inside the ocean. Even when using traditional spaceborne SAR to invert the sea surface flow field, without adjusting the satellite orbit, only a single set of effective vertical baselines and along-track baselines can be provided, and time-varying mixed baselines are inevitable. Thus, it poses a great challenge to the along-track interferometry of space-time-varying ocean currents.

[0004] Therefore, it is urgent to improve the aforementioned defects in the existing technology. Summary of the Invention

[0005] To address the aforementioned problems in existing technologies, this invention provides a distributed satellite orbit simulation method for two-dimensional sea surface flow field inversion. The technical problem to be solved by this invention is achieved through the following technical solution:

[0006] Firstly, this application provides a distributed satellite orbit simulation method for two-dimensional sea surface flow field inversion, including:

[0007] Obtain the initial orbital parameters of the main satellite, and then obtain the orbital parameters of the main satellite based on the initial orbital parameters. The initial orbital parameters of the main satellite include the orbital type, orbital altitude, and downward angle. The parameters of the main satellite include the semi-major axis, eccentricity, orbital inclination, right ascension of the ascending node, argument of perigee, and true anomaly.

[0008] The true anomaly angle in the orbital parameters of the primary satellite is adjusted to obtain the orbital parameters of the first and second auxiliary satellites; wherein the baselines of the primary satellite, the first auxiliary satellite, and the second auxiliary satellite satisfy the range of values ​​for the in-orbit baseline.

[0009] Based on mission requirements, the orbital parameters of the primary satellite, the first auxiliary satellite, and the second auxiliary satellite are fixed, and the orbital parameters of the maneuvering satellite are obtained in order to determine the orbital parameters of the distributed satellites.

[0010] The beneficial effects of this invention are:

[0011] This invention provides a distributed satellite orbit simulation method for two-dimensional sea surface flow field inversion. First, the initial orbital parameters of the main satellite are obtained. Based on these parameters, the orbital parameters of the main satellite are then acquired. The true anomaly angle in the main satellite's orbital parameters is adjusted to obtain the orbital parameters of the first and second auxiliary satellites. The baselines of the main satellite, the first auxiliary satellite, and the second auxiliary satellite satisfy the range of in-orbit baseline values. Second, the orbital parameters of the main satellite, the first auxiliary satellite, and the second auxiliary satellite are fixed, and the orbital parameters of the maneuvering satellite are obtained. Thus, according to mission requirements, the orbital parameters of the first auxiliary satellite, the second auxiliary satellite, and the maneuvering satellite are adjusted to form different distributed satellite formation configurations. This enables the observation of multi-scale, multi-angle ocean phenomena under complex sea conditions, achieving high-precision two-dimensional sea surface flow field inversion and realizing a leap forward in marine dynamic environment detection capabilities.

[0012] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of a distributed satellite formation configuration for two-dimensional sea surface flow field inversion provided in an embodiment of the present invention;

[0014] Figure 2 This is another schematic diagram of a distributed satellite formation configuration for two-dimensional sea surface flow field inversion provided by an embodiment of the present invention;

[0015] Figure 3 This is another schematic diagram of a distributed satellite formation configuration for two-dimensional sea surface flow field inversion provided by an embodiment of the present invention;

[0016] Figure 4 This is a flowchart of a distributed satellite orbit simulation method for two-dimensional sea surface flow field inversion provided in an embodiment of the present invention;

[0017] Figure 5 This is a schematic diagram of a track baseline provided in an embodiment of the present invention;

[0018] Figure 6 This is a schematic diagram of a rail cutting baseline provided in an embodiment of the present invention. Detailed Implementation

[0019] The present invention will be further described in detail below with reference to specific embodiments, but the implementation of the present invention is not limited thereto.

[0020] In existing technologies, the formation of in-orbit interferometric systems for spaceborne SAR mainly includes three forms: First, a single satellite forms multiple closely spaced equivalent phase centers by switching apertures, such as TerraSAR-X, Radarsat-2, and GF-3 satellites; second, a single satellite forms distant equivalent phase centers by extending its arms, such as the SRTM dual-antenna interferometric SAR system; third, a distributed spaceborne SAR system is formed through a two-satellite formation, such as the Helix formation formed by TerraSAR-X and TanDEM-X. The first two methods are limited by radar platform constraints. The first two methods, with their single and fixed baselines, cannot meet the high-precision observation requirements under complex and variable sea conditions. Furthermore, they can only acquire the sea surface current field in the line of sight of the radar beam, failing to acquire the two-dimensional spatial current field of the sea surface, resulting in insufficient spatial dimension for sea surface current field measurement and making it impossible to accurately invert the energy interaction process inside the ocean. The third method can flexibly adjust the baseline to achieve tangential and in-orbit interferometry. However, without adjustment, the dual-satellite orbit can only provide a single set of effective vertical baselines and along-track baselines. At the same time, time-varying mixed baselines are inevitable, posing a great challenge to the in-orbit interferometry processing of space-time-varying ocean currents.

[0021] In view of this, the present invention provides a distributed satellite orbit simulation method for two-dimensional sea surface flow field inversion. The orbital parameters of the main satellite, the first auxiliary satellite, the second auxiliary satellite, and the maneuvering satellite are adjusted according to mission requirements to provide stable multi-baseline, high-precision two-dimensional sea surface flow field inversion, and to achieve a leap in the ability to detect marine dynamic environment.

[0022] Please see Figures 1-4 As shown, Figure 1 This is a schematic diagram of a distributed satellite formation configuration for two-dimensional sea surface flow field inversion provided by an embodiment of the present invention. Figure 2 This is another schematic diagram of a distributed satellite formation configuration for two-dimensional sea surface flow field inversion provided by an embodiment of the present invention. Figure 3 This is another schematic diagram of a distributed satellite formation configuration for two-dimensional sea surface flow field inversion provided by an embodiment of the present invention. Figure 4 This is a flowchart of a distributed satellite orbit simulation method for two-dimensional sea surface flow field inversion provided by an embodiment of the present invention. The distributed satellite orbit simulation method for two-dimensional sea surface flow field inversion provided in this application includes:

[0023] S101. Obtain the initial orbital parameters of the main satellite, and obtain the orbital parameters of the main satellite based on the initial orbital parameters of the main satellite; wherein, the initial orbital parameters of the main satellite include the orbital type, orbital altitude and downward angle of the main satellite, and the orbital parameters of the main satellite include the semi-major axis, eccentricity, orbital inclination, right ascension of the ascending node, argument of perigee and true anomaly.

[0024] S102. Adjust the true anomaly angle in the orbital parameters of the main satellite to obtain the orbital parameters of the first auxiliary satellite and the second auxiliary satellite; wherein the baselines of the main satellite, the first auxiliary satellite and the second auxiliary satellite meet the range of values ​​for the in-orbit baseline.

[0025] S103. Based on the mission requirements, fix the orbital parameters of the primary satellite, the first auxiliary satellite, and the second auxiliary satellite, and obtain the orbital parameters of the maneuvering satellite to determine the orbital parameters of the distributed satellites.

[0026] For details, please continue to see Figures 1-4 As shown in this embodiment, a distributed satellite orbit simulation method for two-dimensional sea surface flow field inversion is provided. First, the initial orbital parameters of the main satellite are obtained. Based on the initial orbital parameters of the main satellite, the orbital parameters of the main satellite are obtained. The true anomaly angle in the orbital parameters of the main satellite is adjusted to obtain the orbital parameters of the first auxiliary satellite and the second auxiliary satellite. The baselines of the main satellite, the first auxiliary satellite, and the second auxiliary satellite meet the range of values ​​for the in-orbit baseline. Second, the orbital parameters of the main satellite, the first auxiliary satellite, and the second auxiliary satellite are fixed, and the orbital parameters of the maneuvering satellite are obtained. In this way, according to the mission requirements, the orbital parameters of the maneuvering satellite are adjusted to form different distributed satellite formation configurations, which have multi-angle observation capabilities. This enables the observation of multi-scale and multi-angle ocean phenomena under complex sea conditions, achieves high-precision two-dimensional sea surface flow field inversion, and realizes a leap in the ability to detect marine dynamic environments.

[0027] It should be noted that the orbital parameters are six-root numbers, which are mathematical variables used to describe the orbital spatial orientation and attitude.

[0028] In an optional embodiment of the present invention, please continue to refer to Figures 1-3 As shown, depending on mission requirements, distributed satellite formation configurations include multiple on-track baseline configurations, on-track and tangential baseline configurations, and mixed on-track and tangential baseline configurations.

[0029] For details, please continue to see Figures 1-3 As shown, this embodiment provides three distributed satellite formation configurations: a multi-track baseline configuration, a track-track and tangential baseline configuration, and a mixed track-track and tangential baseline configuration.

[0030] It should be noted that, Figure 1 The embodiment shown is only a schematic diagram illustrating one positional relationship between the main satellite, the first auxiliary satellite, the second auxiliary satellite, and the maneuvering satellite, and does not represent their actual dimensions; Figure 2 The embodiment shown is only a schematic diagram illustrating one positional relationship between the main satellite, the first auxiliary satellite, the second auxiliary satellite, and the maneuvering satellite, and does not represent their actual dimensions; Figure 3The embodiment shown is only a schematic diagram illustrating one positional relationship between the main satellite, the first auxiliary satellite, the second auxiliary satellite, and the maneuvering satellite, and does not represent their actual dimensions.

[0031] In an optional embodiment of the present invention, please continue to refer to Figure 1 As shown, for a multi-baseline configuration, the orbital parameter process for a maneuvering satellite includes:

[0032] Adjust the true anomaly angle in the orbital parameters of the maneuvering satellite so that, except for the true anomaly angle, all other orbital parameters of the maneuvering satellite are the same as those of the main satellite, the first auxiliary satellite, and the second auxiliary satellite, and the in-orbit baseline of the maneuvering satellite, the main satellite, the first auxiliary satellite, and the second auxiliary satellite meets the range of in-orbit baseline values.

[0033] For details, please continue to see Figure 1 As shown, the main satellite, the first auxiliary satellite, the second auxiliary satellite, and the maneuvering satellite are all distributed along the main satellite's flight path, forming a multi-track baseline configuration. This configuration can effectively ensure signal coherence and expand the unambiguous velocity range while reducing the minimum detectable velocity, thus effectively improving the accuracy of two-dimensional sea surface flow field inversion under complex sea conditions. Alternatively, it can be understood that during the formation flight, fixed track baselines are formed at any time to meet the requirements of two-dimensional sea surface flow field inversion under complex sea conditions.

[0034] In an optional embodiment of the present invention, please continue to refer to Figure 2 As shown, the process of obtaining the orbital parameters of a maneuvering satellite for both in-line and tangential baseline configurations includes:

[0035] Adjust the orbital parameters of the maneuvering satellite, including orbital inclination, right ascension of the ascending node, and true anomaly, so that the orbits of the maneuvering satellite and the main satellite satisfy the double-helix orbit of the Helix configuration, and the effective vertical baselines of the maneuvering satellite and the main satellite satisfy the range of effective vertical baseline values, and the baseline of the maneuvering satellite and the main satellite orbits along the orbit is much smaller than the baseline of the tangent orbit.

[0036] In reality, the accuracy of satellite orbit control is limited. The baselines of the primary satellite and the first and second auxiliary satellites inevitably have tangential baseline components. Adjusting the orbit of the maneuvering satellite so that its tangential baseline component is much larger than its in-orbit baseline component can greatly improve the accuracy of the two-dimensional sea surface inversion flow field by correcting the errors caused by the tangential baselines between the primary satellite and the first and second auxiliary satellites in subsequent ground processing.

[0037] For details, please continue to see Figure 2As shown, in this embodiment, the main satellite, the first auxiliary satellite, and the second auxiliary satellite are distributed along the main satellite's heading, and the maneuvering satellite is on one side of the main satellite. The line connecting the maneuvering satellite and the main satellite is approximately perpendicular to the main satellite's heading, forming an inter-track baseline. The orbits of the maneuvering satellite and the main satellite satisfy the double-helix orbit configuration of the Helix configuration, and simultaneously possess the ability to invert two-dimensional sea surface flow fields and the ability to measure sea surface elevation with high precision, realizing the inversion of all elements of sea surface information. It can also be understood that during formation flight, at any given time, both the orbital baseline and the tangential baseline are simultaneously available, meeting the requirements for two-dimensional sea surface flow field inversion measurement.

[0038] It should be noted that the distance between the position change trajectories of the main satellite and the maneuvering satellite represents the orbital baseline between the main satellite and the maneuvering satellite.

[0039] In an optional embodiment of the present invention, please continue to refer to Figure 3 As shown, for a hybrid baseline configuration of on-track and tangential orbits, the process of obtaining the orbital parameters of a maneuvering satellite includes:

[0040] Adjust the orbital parameters of the maneuvering satellite, including orbital inclination, right ascension of the ascending node, and true anomaly, so that the orbits of the maneuvering satellite and the main satellite satisfy the double-helix orbit configuration of the Helix configuration, and the tangential baselines of the orbits of the maneuvering satellite and the main satellite satisfy the range of tangential baseline values, and the along-orbit baselines of the orbits of the maneuvering satellite and the main satellite satisfy the range of along-orbit baseline values.

[0041] For details, please continue to see Figure 3 As shown, in this embodiment, the main satellite, the first auxiliary satellite, and the second auxiliary satellite are distributed along the main satellite's flight path, and the maneuvering satellite is located to one side of the main satellite. The line connecting the maneuvering satellite and the main satellite intersects the main satellite's flight path but is not perpendicular, forming a hybrid baseline configuration with both along-track and cross-track baseline components. The orbits of the maneuvering satellite and the main satellite satisfy the double-helix orbit of the Helix configuration, which can achieve decoupling and separation of multi-scale ocean phenomena and study of multi-angle scattering models of the sea surface, further improving the dimensionality and accuracy of sea surface flow field measurement. It can also be understood that during formation flight, both along-track and cross-track baselines are available at any time, meeting the requirements for multi-baseline sea surface observation.

[0042] In an optional embodiment of the present invention, the orbital parameters of the maneuvering satellite are obtained through the Hill equations, wherein the expression of the Hill equations is:

[0043]

[0044]

[0045] Where, Δr along For the distance component along the main satellite's heading, Δrcross Let Δr be the distance component along the direction perpendicular to the orbital plane. radial The distance component along the altitude of the main satellite, where 'a' is the semi-major axis of the main satellite's orbit, and 'e' is the distance component along the altitude of the main satellite. c Let ω be the orbital eccentricity of the maneuvering satellite. c Let ΔΩ be the perigee argument of the maneuvering satellite, ΔΩ be the difference between the right ascension of the ascending node of the primary satellite and the ascending node of the maneuvering satellite, and Δi be the difference between the orbital inclination of the primary satellite and the orbital inclination of the maneuvering satellite. s Let be the orbital inclination of the primary satellite, n be the average orbital angular velocity, and u be the Earth's gravitational constant, u = 3.986005 × 10⁻⁶. 14 m 3 / s 2 t is the orbital time.

[0046] In one optional embodiment of the invention, the description will be provided according to the actual situation.

[0047] Depending on the mission requirements, different distributed satellite formation configurations can be achieved through the flexible response of maneuvering satellites.

[0048] It should be noted that in the multi-track baseline configuration, the main satellite, the first auxiliary satellite, the second auxiliary satellite, and the maneuvering satellite are arranged along the main satellite's heading, and the orbital parameters of the above satellites are the same except for the true anomaly angle. In the track-track and tangential baseline configurations, as well as the hybrid baseline configuration, the main satellite, the first auxiliary satellite, and the second auxiliary satellite are arranged along the main satellite's heading, and the maneuvering satellite flies along the orbit with the main satellite in a double-helix phase position relationship. The only difference between them is the positional distribution of the maneuvering satellite and the main satellite along the heading, which can be eliminated by adjusting the true anomaly angle. The specific embodiments of the track-track and tangential baseline configurations will be described below.

[0049] S101. Determine the orbit type, orbital altitude, and downward angle of the main satellite to obtain the preliminary orbit of the main satellite that meets the mission requirements. In this embodiment, the initial input parameters of the main satellite with and with the baseline configuration of the orbit are determined, as shown in Table 1.

[0050] Table 1 Initial orbital parameters of the main satellite

[0051]

[0052]

[0053] Assume the main satellite's orbit is circular, i.e., eccentricity e. s =0. Based on the initial input parameters in Table 1, the six orbital elements of the main satellite are obtained. Please refer to Table 2 for details.

[0054] Table 2. Six orbital elements of the main satellite

[0055] Parameter name numerical values semi-long shaft 6898.1km Eccentricity 0 track inclination 97.8° Right ascension of ascending node 0° Perimeter Argument 0° True near point angle 0°

[0056] S102. Adjust the true anomaly angle in the six orbital roots of the main satellite to obtain the orbital parameters of the first and second auxiliary satellites, so that the baselines of the main satellite, the first auxiliary satellite, and the second auxiliary satellite meet the optimal range of in-orbit baseline values.

[0057] Specifically, the range of values ​​for the in-orbit baseline is obtained through the Hill equations.

[0058] The Hill equations (also known as the Clohessy-Wilshire equations) approximate the relative motions of satellites in a free state within a satellite formation in a rotating coordinate system, serving as a mathematical tool for satellite formation orbit design. This coordinate system transformation allows the differential equations of satellite motion to be approximately linearized; for a near-circular orbit with a period of T0 under an undisturbed Keplerian motion model, a set of solutions to the Hill equations is:

[0059]

[0060]

[0061]

[0062] Where the x-axis is the radial vector from the satellite to the Earth's center, the y-axis is the satellite's motion direction vector, the z-axis is the normal vector of the orbital plane, and Δy i The constant offset of the satellite relative to the rotating coordinate system along the satellite's heading is given by equations (1) to (3). It can be seen from these equations that the satellite's motion along the orbital normal is a simple harmonic vibration, completely independent of the xy plane. The trajectory of the satellite in the xy plane is a semi-major axis A. i An ellipse with an eccentricity of 0.5.

[0063] Because the Earth is not a uniform sphere, the gravitational force experienced by a satellite during its orbital period is nonlinear, resulting in a long-period variation in its orbit. If these variations can be eliminated, the satellite's orbit can be considered stationary; otherwise, the perigee of the satellite's orbit will move along the orbit, a motion called libration, the period of which is calculated as follows:

[0064]

[0065] in, The rate of change of the perigee angle is calculated to have a period of approximately 104 days.

[0066] To describe the relative motion between satellites, a Cartesian rotating coordinate system needs to be established. In this system, the x-axis (the satellite's motion along its trajectory) points in the direction of flight, the y-axis (the motion perpendicular to the orbital plane) is parallel to the orbital normal vector, and the z-axis (the motion in the altitude direction) points from the Earth's center of mass to the satellite's center of mass. Mathematically, the unit vectors of these three axes can be represented as:

[0067]

[0068]

[0069]

[0070] in, For the satellite velocity vector, The satellite's position vector; the phase relationship between the two satellites can be expressed as:

[0071]

[0072] In a near-circular orbit, the motion can be approximated as linear, and the magnitudes of the components are expressed as:

[0073]

[0074] Δr cross =-aΔicos(u) (10)

[0075] Δr radial =-aΔesin(u+ψ) (11)

[0076] Where Δe is the difference in eccentricity between the two stars, and u is the latitude value. It is an offset along any heading. Let be the difference in the true anomaly angle between the two stars; since the orbital planes of the two stars have the same inclination, Δi is the angle between the right ascensions of the ascending nodes; therefore, a hyperbolic configuration is defined by three parameters: the altitude offset is aΔe, the horizontal offset is aΔi, and the libration angle ψ, where ψ is at T libration The angle changes from 0 degrees to 360 degrees within a time period; stable data acquisition requires a constant balance phase ψ, and orbit control is achieved through the propulsion system to meet the mapping requirements.

[0077] For both the first and second auxiliary satellites, the difference in eccentricity between the first and second auxiliary satellites and the main satellite is Δe = 0. Therefore, the range of the baseline along the track is 75m to 300m, specifically:

[0078]

[0079] According to formula (12), the true anomaly angles of the first and second auxiliary satellites can be calculated. Finally, the orbital elements of the first and second auxiliary satellites are shown in Table 3.

[0080] Table 3. Orbital elements of the first and second auxiliary satellites

[0081] orbital elements First auxiliary satellite Second auxiliary satellite semi-long shaft 6898.1km 6898.1km Eccentricity 0 0 track inclination 97.8° 97.8° Right ascension of ascending node 0° 0° Perimeter Argument 0° 0° True near point angle -0.00062566° 0.0025°

[0082] S103. Keep the orbital parameters of the main satellite, the first auxiliary satellite, and the second auxiliary satellite unchanged, and determine the orbital parameters of the maneuvering satellite according to the configuration type.

[0083] Assuming the main satellite and the maneuvering satellite have the same semi-major axis, the Hill equations for near-circular orbits under this assumption are given as follows:

[0084]

[0085]

[0086] Where, Δr along For the distance component along the main satellite's heading, Δr cross Let Δr be the distance component along the direction perpendicular to the orbital plane. radial The distance component along the altitude of the main satellite, where 'a' is the semi-major axis of the main satellite's orbit, and 'e' is the distance component along the altitude of the main satellite. c Let ω be the orbital eccentricity of the maneuvering satellite. c Let ΔΩ be the perigee argument of the maneuvering satellite, ΔΩ be the difference between the right ascension of the ascending node of the primary satellite and the ascending node of the maneuvering satellite, and Δi be the difference between the orbital inclination of the primary satellite and the orbital inclination of the maneuvering satellite. s Let be the orbital inclination of the main satellite, n be the average orbital angular velocity, u be the Earth's gravitational constant, and t be the orbital time.

[0087] Let Δi = 0, then formula (13) can be simplified to:

[0088]

[0089] Since the baseline value ranges from 300m to 600m, we assume here that the maximum vertical baseline length of the main satellite and the maneuvering satellite in the Helix formation configuration is 600m, and that the projection of the Helix configuration into the vertical heading plane is circular. Therefore, the input conditions for the configuration design are:

[0090]

[0091] According to formula (15), the orbital parameters of the maneuvering satellite can be calculated. Finally, the orbital elements of the main satellite and the maneuvering satellite in the Helix configuration are shown in Table 4.

[0092] Table 4 Orbital parameters of the primary satellite and maneuvering satellite in the Helix configuration

[0093] orbital elements main satellite Mobile satellite semi-long shaft 6898.1km 6898.1km Eccentricity 0 0 track inclination 97.8° 97.8° Right ascension of ascending node 0° 0.00506° Perimeter Argument 0° 0° True near point angle 0° 0.0011°

[0094] Through STK simulation analysis, the baselines formed by the four satellites under the in-orbit and tangential baseline configurations are as follows: Figure 5 and Figure 6 As shown, Figure 5 This is a schematic diagram of a track baseline provided in an embodiment of the present invention. Figure 6 This is a schematic diagram of a tangential baseline provided in an embodiment of the present invention. As can be seen from the diagram, at any moment within one orbital period, the main satellite and the first and second auxiliary satellites always have a fixed tangential baseline, which can be flexibly adjusted according to observation needs to obtain the best two-dimensional sea surface flow field inversion capability. The main satellite and the maneuvering satellite always have a long tangential baseline, which can obtain the best sea surface flow field inversion error correction capability. At the same time, the first and second auxiliary satellites have fixed tangential baselines, and the maneuvering satellite and the main satellite form a double helix structure with no intersection points between their orbits, which can effectively avoid collisions.

[0095] In addition, under the multi-baseline configuration, the first auxiliary satellite, the second auxiliary satellite, and the maneuvering satellite modify their true anomaly angles to obtain stable baselines with the main satellite, similar to the first and second auxiliary satellites under the along-orbit and tangential configurations. Under the along-orbit and cross-orbit configuration, the maneuvering satellites in this configuration also satisfy the double-helix orbit of the Helix configuration with the main satellite, and differ from the maneuvering satellites under the along-orbit and tangential configurations only in their true anomaly angles. This configuration has the capability of multi-baseline ocean observation, enabling the decoupling and separation of multi-scale ocean phenomena and the study of multi-angle scattering models of the sea surface, further improving the dimensionality and accuracy of sea surface flow field measurements.

[0096] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations are intended to cover non-exclusive inclusion, such that an article or device comprising a list of elements includes not only those elements but also other elements not expressly listed. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the article or device comprising said element. Terms such as "connected" or "linked" are not limited to physical or mechanical connections but can include electrical connections, whether direct or indirect. The orientations or positional relationships indicated by terms such as "upper," "lower," "left," and "right" are based on the orientations or positional relationships shown in the accompanying drawings and are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as limiting the invention.

[0097] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features or characteristics described may be combined in any suitable manner in one or more embodiments or examples. In addition, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0098] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. A distributed satellite orbit simulation method for two-dimensional sea surface flow field inversion, characterized in that, include: The initial orbital parameters of the main satellite are obtained, and the orbital parameters of the main satellite are obtained based on the initial orbital parameters of the main satellite; wherein, the initial orbital parameters of the main satellite include the orbital type, orbital altitude and downward angle of the main satellite, and the orbital parameters of the main satellite include the semi-major axis, eccentricity, orbital inclination, right ascension of the ascending node, argument of perigee and true anomaly; The true anomaly angle in the orbital parameters of the primary satellite is adjusted to obtain the orbital parameters of the first auxiliary satellite and the second auxiliary satellite; wherein the baselines of the primary satellite, the first auxiliary satellite, and the second auxiliary satellite satisfy the range of in-orbit baseline values. According to the mission requirements, the orbital parameters of the main satellite, the first auxiliary satellite and the second auxiliary satellite are fixed, and the orbital parameters of the maneuvering satellite are obtained to determine the orbital parameters of the distributed satellites; According to mission requirements, distributed satellite formation configurations include multiple along-track baseline configurations, along-track and tangential-track baseline configurations, and mixed along-track and tangential-track baseline configurations. Specifically, a configuration where the main satellite, the first auxiliary satellite, the second auxiliary satellite, and the maneuvering satellite are all distributed along the main satellite's heading forms a multiple along-track baseline configuration; a configuration where the main satellite, the first auxiliary satellite, and the second auxiliary satellite are distributed along the main satellite's heading, with the maneuvering satellite to one side of the main satellite and the line connecting the maneuvering satellite and the main satellite nearly perpendicular to the main satellite's heading forms a tangential-track baseline; and a configuration where the main satellite, the first auxiliary satellite, and the second auxiliary satellite are distributed along the main satellite's heading, with the maneuvering satellite to one side of the main satellite and the line connecting the maneuvering satellite and the main satellite intersects the main satellite's heading but is not perpendicular, forms a mixed baseline configuration with both along-track and tangential-track baseline components. For the aforementioned multi-baseline configuration, the process for obtaining the orbital parameters of the maneuvering satellite is as follows: Adjust the true anomaly angle in the orbital parameters of the maneuvering satellite so that, except for the true anomaly angle, all other orbital parameters of the maneuvering satellite are the same as those of the main satellite, the first auxiliary satellite, and the second auxiliary satellite, and the in-orbit baseline of the maneuvering satellite, the main satellite, the first auxiliary satellite, and the second auxiliary satellite meets the range of in-orbit baseline values. For the aforementioned baseline configurations (both along and tangential), the process for obtaining the orbital parameters of the maneuvering satellite includes: The orbital parameters of the maneuvering satellite, including the orbital inclination, right ascension of the ascending node, and true anomaly, are adjusted so that the orbits of the maneuvering satellite and the main satellite satisfy the double-helix orbit configuration of the Helix configuration, and the effective vertical baselines of the maneuvering satellite's orbit and the main satellite's orbit satisfy the range of effective vertical baseline values. The baseline of the maneuvering satellite's orbit along the orbit and the main satellite's orbit is much smaller than the baseline of the tangent orbit. For the aforementioned hybrid baseline configuration of in-orbit and tangential orbits, the process for obtaining the orbital parameters of the maneuvering satellite is as follows: The orbital parameters of the maneuvering satellite, including the orbital inclination, right ascension of the ascending node, and true anomaly, are adjusted so that the orbits of the maneuvering satellite and the main satellite satisfy the double-helix orbit configuration of the Helix configuration. Furthermore, the tangential baselines of the orbits of the maneuvering satellite and the main satellite satisfy the tangential baseline value range, and the along-orbit baselines of the orbits of the maneuvering satellite and the main satellite satisfy the along-orbit baseline value range.

2. The distributed satellite orbit simulation method for two-dimensional sea surface flow field inversion according to claim 1, characterized in that, The orbital parameters of the maneuvering satellite are obtained through the Hill equations, where the expression of the Hill equations is: ； ； in, The distance component along the main satellite's heading. This represents the distance component along the direction perpendicular to the orbital plane. The distance component along the altitude of the main satellite, The semi-major axis of the orbit of the primary satellite is... The orbital eccentricity of the said maneuvering satellite, The perigee argument of the orbit of the said mobile satellite. The difference between the right ascension of the ascending node of the primary satellite's orbit and the right ascension of the ascending node of the maneuvering satellite's orbit. The difference between the orbital inclination of the primary satellite and the orbital inclination of the maneuvering satellite. The orbital inclination of the primary satellite. The average orbital angular velocity, The gravitational constant of Earth, For orbital time.

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