Distributed satellite formation configuration method for two-dimensional sea surface flow field inversion

Abstract

The application discloses a kind of distributed satellite formation configuration methods for two-dimensional sea surface flow field inversion, it is related to distributed SAR system technical field, including: main satellite;Wherein, the heading of main satellite is first direction;First auxiliary satellite and second auxiliary satellite, respectively, are located in the two sides of main satellite along first direction;Mobile satellite, according to task demand, is located between main satellite and first auxiliary satellite, or;It is located between main satellite and second auxiliary satellite, or;It is located in the two sides of main satellite along second direction, or;It is located in the two sides of first auxiliary satellite or second auxiliary satellite along second direction;Second direction and first direction intersect.This application can realize the leap of ocean dynamic environment detection capability according to observation task requirement.

Description

Technical Field

[0001] This invention belongs to the field of distributed SAR system technology, specifically relating to a distributed satellite formation configuration 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-weather, all-time availability, and high spatial resolution. It can utilize the advantages 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 formation configuration 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 formation configuration method for two-dimensional sea surface flow field inversion, including:

[0007] The main satellite; where the main satellite's heading is the first direction;

[0008] The first and second auxiliary satellites are located on either side of the main satellite along the first direction, respectively.

[0009] The mobile satellite, depending on mission requirements, is located between the main satellite and the first auxiliary satellite, or; between the main satellite and the second auxiliary satellite, or; on both sides of the main satellite along the second direction, or; on both sides of the first or second auxiliary satellite along the second direction; the second direction intersects with the first direction.

[0010] The beneficial effects of this invention are:

[0011] This invention provides a distributed satellite formation configuration method for two-dimensional sea surface flow field inversion. First, the position of the master satellite is obtained, and the positions of the first and second auxiliary satellites are determined based on the position of the master satellite. Then, according to the mission requirements, the maneuvering satellites are mobilized to be in different positions to form different configurations, so as to provide a stable observation baseline. At the same time, different configurations can realize the observation of multi-scale and multi-angle ocean phenomena under complex sea conditions, achieve high-precision two-dimensional sea surface flow field inversion, and realize a leap in the ability of marine dynamic environment detection.

[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 in an embodiment of the present invention. Detailed Implementation

[0016] 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.

[0017] 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 through aperture switching, such as TerraSAR-X, Radarsat-2, and GF-3 satellites; second, a single satellite forms distant equivalent phase centers through an extended arm, 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 single and fixed baseline cannot meet the high-precision observation requirements under complex and variable sea conditions. At the same time, the first two methods can only obtain the sea surface flow field in the line of sight of the radar beam, and cannot obtain 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. The third method can flexibly adjust the baseline to realize tangential interferometry and along-track interferometry. However, without adjustment, the binary orbit can only provide a single set of vertical effective baselines and along-track baselines. At the same time, time-varying mixed baselines are inevitable, which poses a great challenge to the along-track interferometry processing of space-time-varying ocean currents.

[0018] In view of this, the present invention provides a distributed satellite formation configuration for two-dimensional sea surface flow field inversion. According to mission requirements, the positions of mobile satellites are adjusted in real time to form different satellite formation configurations to conduct multi-scale ocean phenomenon observations under complex sea conditions, realize high-precision two-dimensional sea surface flow field inversion, and achieve a leap in the ability of marine dynamic environment detection.

[0019] Please see Figures 1-3 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. The distributed satellite formation configuration method for two-dimensional sea surface flow field inversion provided in this application includes:

[0020] The main satellite; where the main satellite's heading is the first direction;

[0021] The first and second auxiliary satellites are located on either side of the main satellite along the first direction, respectively.

[0022] The mobile satellite, depending on mission requirements, is located between the main satellite and the first auxiliary satellite, or; between the main satellite and the second auxiliary satellite, or; on both sides of the main satellite along the second direction, or; on both sides of the first or second auxiliary satellite along the second direction; the second direction intersects with the first direction.

[0023] It should be noted that the SAR payloads carried by the above satellites are all of the slant-look dual-beam system, which inverts the sea surface flow velocity in the front and back beam directions respectively, and completes the inversion of the two-dimensional sea surface flow field after vector synthesis.

[0024] For details, please continue to see Figures 1-3 As shown in this embodiment, a distributed satellite formation configuration for two-dimensional sea surface flow field inversion is provided. First, the position of the master satellite is obtained, and the positions of the first and second auxiliary satellites are determined based on the position of the master satellite. Then, according to the mission requirements, the maneuvering satellites are mobilized to be in different positions to form different configurations, so as to provide stable in-orbit and tangential baselines. At the same time, different configurations can be formed to realize the observation of multi-scale ocean phenomena under complex sea conditions, achieve high-precision two-dimensional sea surface flow field inversion, and realize a leap in the ability of marine dynamic environment detection.

[0025] It should be noted that the main satellite, the first auxiliary satellite, the second auxiliary satellite, and the maneuvering satellite all have predetermined orbits around the Earth. Each satellite flies along its corresponding orbit throughout its orbital period. In each configuration, the satellite maintains a fixed configuration in its respective orbit to achieve Earth observation; for example... Figures 1-3 As shown, for ease of understanding, this invention uses vector axes to represent the positional relationship between the main satellite, the first auxiliary satellite, the second auxiliary satellite, and the maneuvering satellite at a certain moment. One vector represents the direction of satellite velocity, and the other vector represents the direction perpendicular to the satellite velocity. In addition, the coordinate axes also represent the positional constraints on the main satellite, the first auxiliary satellite, the second auxiliary satellite, and the maneuvering satellite at any given moment.

[0026] It should also be noted that, Figure 1 The embodiments shown are only schematic representations of the positional relationships of the main satellite, the first auxiliary satellite, the second auxiliary satellite, and the maneuvering satellite, and do not represent the actual dimensions; Figure 2 The embodiments shown are only schematic representations of the positional relationships of the main satellite, the first auxiliary satellite, the second auxiliary satellite, and the maneuvering satellite, and do not represent the actual dimensions; Figure 3 The embodiments shown are only schematic representations of the positional relationships of the main satellite, the first auxiliary satellite, the second auxiliary satellite, and the maneuvering satellite, and do not represent the actual dimensions.

[0027] In an optional embodiment of the present invention, the distance between the primary satellite and the first auxiliary satellite, and the distance between the primary satellite and the second auxiliary satellite, are both less than the extreme in-orbit baseline length.

[0028] Stable long-track baselines and short-track baselines are formed between the main satellite and the first auxiliary satellite, as well as between the main satellite and the second auxiliary satellite.

[0029] Specifically, in this embodiment, the distance range between the primary satellite and the first auxiliary satellite, and the distance range between the primary satellite and the second auxiliary satellite, must be greater than the satellite's safe braking distance to avoid collisions between satellites. The distance between the primary satellite and the first auxiliary satellite, and the distance between the primary satellite and the second auxiliary satellite, are both less than the limit orbital baseline length. The limit orbital baseline is the maximum orbital baseline that ensures coherence between the data of the primary satellite and the first and second auxiliary satellites. Once the limit orbital baseline is exceeded, the data will be completely decoherent, making orbital interference processing impossible.

[0030] In addition, stable long and short orbital baselines need to be formed between the main satellite and the first auxiliary satellite, as well as between the main satellite and the second auxiliary satellite. By combining the long and short orbital baselines, the detection range of unambiguous flow velocity can be expanded while the minimum detectable velocity can be reduced, thus realizing the inversion of the two-dimensional sea surface flow field.

[0031] In an optional embodiment of the present invention, please continue to refer to Figure 1 As shown, the maneuvering satellite is located between the main satellite and the first auxiliary satellite, or between the main satellite and the second auxiliary satellite, forming a multi-track baseline configuration.

[0032] For details, please continue to see Figure 1 As shown, in this embodiment, 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.

[0033] In an optional embodiment of the invention, the length of the in-orbit baseline between the main satellite and the maneuvering satellite is between the long in-orbit baseline and the short in-orbit baseline.

[0034] Specifically, in this embodiment, in the multi-track baseline configuration, the track baseline length between the main satellite and the maneuvering satellite is between the long and short track baselines, which complements the long and short track baselines formed by the main satellite, the first auxiliary satellite, and the second auxiliary satellite, thus realizing the track-track multi-baseline configuration.

[0035] In an optional embodiment of the present invention, please continue to refer to Figure 2As shown, the maneuvering satellite is located on both sides of the main satellite along the second direction, and the maneuvering satellite and the main satellite form a tangential baseline, constituting a configuration of a tangential baseline and a traverse baseline. The second direction is perpendicular to the first direction.

[0036] For details, please continue to see Figure 2 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, while the maneuvering satellites are distributed on both sides of the main satellite. The line connecting the maneuvering satellites and the main satellite is perpendicular to the main satellite's flight path, forming a vertical baseline, which greatly improves the inversion capability of the two-dimensional sea surface flow field. This is because the baselines of the main satellite and the first and second auxiliary satellites inevitably have tangential baseline components. Adjusting the orbit of the maneuvering satellites makes their tangential baseline components much larger than their in-orbit baseline components allows for correction of errors caused by tangential baselines between the main satellite and the first and second auxiliary satellites during subsequent ground processing, thereby improving the accuracy of the two-dimensional sea surface inversion flow field. It can also be understood that during formation flight, both in-orbit and tangential baselines are present at any given time, meeting the requirements for two-dimensional sea surface flow field inversion measurement.

[0037] In an optional embodiment of the present invention, the distance between the primary satellite and the maneuvering satellite is less than the limit tangent baseline length; a stable tangent baseline is formed between the primary satellite and the maneuvering satellite.

[0038] Specifically, in this embodiment, the distance between the main satellite and the maneuvering satellite must first be greater than the satellite's safe braking distance to avoid collisions between the satellites; the distance between the main satellite and the maneuvering satellite must also be less than the system's limit tangent baseline length; the limit tangent baseline is the maximum tangent baseline that ensures coherence between the data of the main satellite and the maneuvering satellite. Once the limit tangent baseline is exceeded, the data will be completely decoherent, thus making tangent interference processing impossible.

[0039] In an optional embodiment of the present invention, please continue to refer to Figure 3 As shown, the maneuvering satellite is located on one side of the main satellite along the second direction, and the baseline formed by the maneuvering satellite and the main satellite has both a along-track baseline component and a cross-track baseline component, forming a along-track baseline and a hybrid baseline configuration. The second direction and the first direction are not perpendicular.

[0040] For details, please continue to see Figure 3As 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, while the maneuvering satellite is distributed 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 to it. There are both inter-orbital baselines and in-orbital baselines, forming a configuration of in-orbital baselines and hybrid baselines. This configuration enables 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. It can also be understood that during formation flight, both in-orbital baselines and inter-orbital baselines are available at any given time, meeting the needs of multi-angle and multi-baseline sea surface observation.

[0041] In an optional embodiment of the present invention, the along-orbit and tangential components of the mixed baseline of the primary satellite and the maneuvering satellite are less than the lengths of the limiting along-orbit baseline and the limiting tangential baseline.

[0042] Specifically, in this embodiment, the distance between the main satellite and the maneuvering satellite must first be greater than the satellite's safe braking distance to avoid collisions between the satellites; the on-orbit and tangential components of the mixed baseline of the main satellite and the maneuvering satellite must also be less than the system's limit on-orbit baseline and limit tangential baseline length, respectively, to ensure coherence between the data of the main satellite and the maneuvering satellite.

[0043] 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 apparatus 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 apparatus that includes 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.

[0044] 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.

[0045] 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 formation configuration method for two-dimensional sea surface flow field inversion, characterized in that, include: The main satellite; wherein the heading of the main satellite is the first direction; The first and second auxiliary satellites are located on either side of the main satellite along the first direction, respectively; the distance between the main satellite and the first auxiliary satellite, and the distance between the main satellite and the second auxiliary satellite, are both less than the extreme in-orbit baseline length; a stable long in-orbit baseline and a short in-orbit baseline are formed between the main satellite and the first auxiliary satellite, and between the main satellite and the second auxiliary satellite. The maneuvering satellite, depending on mission requirements, is located between the primary satellite and the first auxiliary satellite, or; located between the primary satellite and the second auxiliary satellite, forming a multi-track baseline configuration, where the track baseline length between the primary satellite and the maneuvering satellite is between a long track baseline and a short track baseline; or; located on both sides of the primary satellite along a second direction, where the distance between the primary satellite and the maneuvering satellite is less than the limiting tangential baseline length, where the primary satellite and the maneuvering satellite form a stable tangential baseline, and the maneuvering satellite and the primary satellite form a perpendicular baseline, forming a track baseline and tangential baseline configuration, where the second direction is perpendicular to the first direction; or; located on both sides of the first auxiliary satellite or the second auxiliary satellite along a second direction, where the maneuvering satellite is located on both sides of the primary satellite along a second direction, and the maneuvering satellite and the primary satellite form an inter-track baseline, forming a track baseline and hybrid baseline configuration, where the second direction is not perpendicular to the first direction, and the track and tangential components of the inter-track baseline of the primary satellite and the maneuvering satellite are less than the limiting track baseline and the limiting tangential baseline length.

Images