Target group observation based on sar satellite, target group observation method and device

Abstract

The application provides a target group observation method and device based on a SAR satellite, comprising obtaining first key information of a target group to be observed and second key information of a SAR satellite determined for the target group to be observed, generating an attitude adjustment scheme of the SAR satellite based on a maximum azimuth dimension of the SAR satellite determined based on the first key information and the second key information, and generating an observation plan of the SAR satellite relative to the target group to be observed based on the attitude adjustment scheme. According to the above method, the attitude of the SAR satellite can be continuously controlled according to the attitude adjustment scheme when the SAR satellite executes the observation plan, so that the antenna field of view can cover the specified target area for a longer time, thereby improving the single-pass dense observation capability of the SAR satellite for the target group in the region.

Description

Technical Field

[0001] This invention relates to the field of satellite target observation technology, and in particular to a target group observation method and apparatus based on SAR satellites. Background Technology

[0002] Synthetic Aperture Radar (SAR) satellites possess all-weather, all-day, high-resolution Earth observation capabilities, playing a crucial role in monitoring key land areas and naval targets. Currently, when implementing spotlight or sliding spotlight imaging modes, SAR satellites can control the beam direction through the two-dimensional electronic scanning of their onboard phased array antennas, facilitating imaging observation of target areas within the antenna's field of view. However, because the scanning angle of phased array antennas is typically limited, it is difficult for the antenna's field of view to cover a designated target area for an extended period, thus affecting the SAR satellite's ability to conduct single-pass, dense observation of target groups within a region. Summary of the Invention

[0003] The purpose of this invention is to provide a target group observation method, target group observation method and device based on SAR satellite, which enables the antenna field of view to cover a specified target area for a longer period of time, thereby improving the single-flight dense observation capability of SAR satellite for target groups in the area.

[0004] To achieve the above objectives, in a first aspect, the present invention provides a target swarm observation method based on SAR satellites, which is applied to control equipment in a SAR satellite system, comprising:

[0005] Acquire first key information about the target group to be observed and second key information about the SAR satellite determined for the target group to be observed. The first key information includes at least the geographical location of the area to be observed corresponding to the target group to be observed. The second key information includes at least the orbital altitude of the SAR satellite, the speed of the SAR satellite relative to the ground, and the payload imaging control parameters of the SAR satellite.

[0006] Based on the first key information and the second key information, the maximum azimuth angle of the SAR satellite is determined, and an attitude adjustment scheme for the SAR satellite is generated based on the maximum azimuth angle. The maximum azimuth angle is used to characterize the maximum pitch angle that the SAR satellite can image relative to the area to be observed. The attitude adjustment scheme includes at least the initial time and the end time set corresponding to the maximum azimuth angle, and the attitude adjustment angular velocity between the initial time and the end time.

[0007] Based on the attitude adjustment scheme, an observation plan for the SAR satellite relative to the target group to be observed is generated, and the observation plan is sent to the SAR satellite so that the SAR satellite executes the observation plan. During the execution process, from the initial time to the end time, the pitch angle of the SAR satellite is adjusted at least by the attitude adjustment angular velocity.

[0008] In one optional implementation, generating the attitude adjustment scheme for the SAR satellite based on the maximum azimuth oblique angle includes obtaining the cutoff time and the attitude adjustment angular velocity in the following manner:

[0009] The attitude adjustment time of the SAR satellite is calculated using the following formula:

[0010]

[0011] Among them, T a R represents the attitude adjustment time. e H0 represents the Earth's radius, H0 represents the orbital altitude of the SAR satellite, and φ represents the Earth's radius. p V represents the maximum azimuth angle of view. s This indicates the orbital speed of the SAR satellite relative to the ground;

[0012] Based on the initial time set according to the maximum azimuth oblique angle and the attitude adjustment duration, the corresponding cutoff time and attitude adjustment angular velocity are determined, wherein the expression for the attitude adjustment angular velocity is:

[0013] In one optional implementation, generating the attitude adjustment scheme for the SAR satellite based on the maximum azimuth oblique angle includes obtaining the cutoff time and the attitude adjustment angular velocity in the following manner:

[0014] The attitude adjustment time of the SAR satellite is calculated using the following formula:

[0015]

[0016] Among them, T a_l R represents the attitude adjustment time. e H0 represents the Earth's radius, H0 represents the orbital altitude of the SAR satellite, and φ represents the Earth's radius. p V represents the maximum azimuth angle of view. s This indicates the orbital speed of the SAR satellite relative to the ground; W az The length of the region to be observed along the track direction;

[0017] Based on the initial time set according to the maximum azimuth oblique angle and the attitude adjustment duration, the corresponding cutoff time and attitude adjustment angular velocity are determined, wherein the expression for the attitude adjustment angular velocity is:

[0018] In one optional implementation, generating the observation plan of the SAR satellite relative to the target group based on the attitude adjustment scheme includes:

[0019] Obtain the preset imaging task of the SAR satellite, wherein the preset imaging task includes at least: a preset azimuth beam pointing angle for the phased array antenna carried by the SAR satellite, and a preset range beam pointing angle for the phased array antenna;

[0020] The preset azimuth beam pointing angle and the preset distance beam pointing angle are scanned and compensated to obtain the corresponding target azimuth beam pointing angle and target distance beam pointing angle.

[0021] The SAR satellite generates an observation plan relative to the target group based on the target azimuth beam pointing angle, the target range beam pointing angle, and the attitude adjustment scheme.

[0022] In one optional implementation, the step of scanning and compensating the preset azimuth beam pointing angle and the preset range beam pointing angle to obtain the corresponding target azimuth beam pointing angle and target range beam pointing angle includes:

[0023] The following formulas are used to calculate the corresponding target azimuth beam pointing angle and target range beam pointing angle of the SAR satellite at each on-orbit time:

[0024] θ az_r (t)=sin -1 (x)

[0025] θ rg_r (t)=tan -1 (y / z)

[0026] in:

[0027]

[0028]

[0029] θ az_s θ represents the preset azimuth beam pointing angle. rg_s θ represents the preset distance-dimensional beam pointing angle. az_r (t) represents the target azimuth beam pointing angle at a given on-orbit moment, θ rg_r(t) represents the target range beam pointing angle corresponding to a given on-orbit moment, φ p (t) represents the elevation angle of the SAR satellite at a given on-orbit moment, φ y (t) represents the yaw angle of the SAR satellite at a given on-orbit moment, φ r (t) represents the roll angle of the SAR at a given on-orbit time.

[0030] In one alternative implementation, before sending the observation plan to the SAR satellite, the method further includes:

[0031] A pre-adjustment command is sent to the SAR satellite so that the SAR satellite responds to the pre-adjustment command and adjusts the roll angle of the SAR satellite at a specified pre-adjustment time, wherein the pre-adjustment time is earlier than the initial time.

[0032] Secondly, this application provides a target swarm observation method, which is applied to SAR satellites in a SAR satellite system, including:

[0033] The system receives an observation plan sent by a control device, wherein: the observation plan is generated by the control device based on an attitude adjustment scheme, the attitude adjustment scheme is generated by the control device based on a maximum azimuth angle, the maximum azimuth angle is obtained by the control device based on first key information of the target group to be observed and second key information of the SAR satellite, the maximum azimuth angle is used to characterize: the maximum elevation angle that the SAR satellite can image relative to the area to be observed, the first key information includes at least: the geographical location of the area to be observed corresponding to the target group to be observed, the second key information includes at least: the orbital altitude of the SAR satellite, the motion speed of the SAR satellite relative to the ground, and the payload imaging control parameters of the SAR satellite, and the attitude adjustment scheme includes at least: an initial time and an end time set corresponding to the maximum azimuth angle, and the attitude adjustment angular velocity between the initial time and the end time;

[0034] The observation plan is executed to observe the target group to be observed. During the execution process: from the initial time to the end time, the elevation angle of the SAR satellite is adjusted at least by the attitude adjustment angular velocity.

[0035] In one optional implementation, before receiving the observation plan sent by the control device, the method further includes:

[0036] In response to a pre-adjustment command sent by the control device, the roll angle of the SAR satellite is adjusted at a specified pre-adjustment time, wherein the pre-adjustment time is earlier than the initial time.

[0037] Thirdly, the present invention provides a target group observation device based on SAR satellites, wherein the device is installed in the control equipment of the SAR satellite system, and the device includes:

[0038] The key information acquisition module is used to acquire first key information of the target group to be observed and second key information of the SAR satellite determined for the target group to be observed. The first key information includes at least the geographical location of the area to be observed corresponding to the target group to be observed. The second key information includes at least the orbital altitude of the SAR satellite, the motion speed of the SAR satellite relative to the ground, and the payload imaging control parameters of the SAR satellite.

[0039] An attitude adjustment scheme generation module is used to determine the maximum azimuth angle of the SAR satellite based on the first key information and the second key information, and to generate an attitude adjustment scheme for the SAR satellite based on the maximum azimuth angle. The maximum azimuth angle is used to characterize the maximum pitch angle that the SAR satellite can image relative to the area to be observed. The attitude adjustment scheme includes at least the initial time and the end time set for the maximum azimuth angle, and the attitude adjustment angular velocity between the initial time and the end time.

[0040] An observation plan generation module is used to generate an observation plan for the SAR satellite relative to the target group to be observed based on the attitude adjustment scheme, and send the observation plan to the SAR satellite so that the SAR satellite executes the observation plan. During the execution process, from the initial time to the end time, the pitch angle is adjusted at least by the attitude adjustment angular velocity.

[0041] Fourthly, the present invention provides a target group observation device, the device being installed on a SAR satellite in the SAR satellite system, the device comprising:

[0042] An observation plan receiving module is used to receive an observation plan sent by a control device, wherein: the observation plan is generated by the control device based on an attitude adjustment scheme, the attitude adjustment scheme is generated by the control device based on a maximum azimuth angle, the maximum azimuth angle is obtained by the control device based on first key information of the target group to be observed and second key information of the SAR satellite, the maximum azimuth angle is used to characterize: the maximum elevation angle that the SAR satellite can image relative to the area to be observed, the first key information includes at least: the geographical location of the area to be observed corresponding to the target group to be observed, the second key information includes at least: the orbital altitude of the SAR satellite, the motion speed of the SAR satellite relative to the ground, and the payload imaging control parameters of the SAR satellite, and the attitude adjustment scheme includes at least: an initial time and an end time set corresponding to the maximum azimuth angle, and an attitude adjustment angular velocity between the initial time and the end time;

[0043] The observation plan execution module is used to execute the observation plan to observe the target group to be observed. During the execution process, from the initial time to the end time, the elevation angle of the SAR satellite is adjusted by the attitude adjustment angular velocity.

[0044] Fifthly, the present invention provides an electronic device, comprising: a memory; and a processor; the memory storing instructions executable by the processor, wherein the processor executes the instructions to implement the target swarm observation method based on SAR satellite as described in any of the first aspects above, or to implement the target swarm observation method as described in any of the second aspects above.

[0045] The technical effects of this invention are as follows:

[0046] This invention provides a target group observation method, method and apparatus based on SAR satellites. The method generates an attitude adjustment scheme for the SAR satellite by determining the maximum azimuth angle of the SAR satellite through first key information and second key information. The method then generates an observation plan for the SAR satellite relative to the target group to be observed through the attitude adjustment scheme. As the SAR satellite executes the observation plan, it can continuously control the attitude change of the SAR satellite according to the attitude adjustment scheme, so that the antenna field of view can cover the specified target area for a longer period of time, thereby improving the SAR satellite's single-flight dense observation capability for the target group in the area. Attached Figure Description

[0047] The accompanying drawings are included to provide a further understanding of this application and form part of this application. The drawings illustrate embodiments of this application and, together with this specification, serve to explain the principles of this application.

[0048] In the attached image:

[0049] Figure 1 This is a schematic diagram of a SAR satellite system provided in this application;

[0050] Figure 2 This is a flowchart of a target swarm observation method based on SAR satellites provided in this application;

[0051] Figure 3 This is a schematic diagram of a method for obtaining the cutoff time and attitude adjustment angular velocity provided in this application;

[0052] Figure 4 This is a schematic diagram of another method for obtaining the cutoff time and attitude adjustment angular velocity provided in this application;

[0053] Figure 5 This is a flowchart of a target swarm observation method provided in this application;

[0054] Figure 6a , Figure 6b This is a schematic diagram of one of the simulation results provided in this application;

[0055] Figure 7a , Figure 7b This is a schematic diagram of the second simulation result provided in this application;

[0056] Figure 8 This is a schematic diagram of a target swarm observation device based on SAR satellites provided in this application;

[0057] Figure 9 This is a schematic diagram of a target group observation device provided in this application;

[0058] Figure 10 This is a schematic diagram of an electronic device provided in this application. Detailed Implementation

[0059] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are merely some examples or embodiments of this application. For those skilled in the art, these drawings can be applied to other similar scenarios without creative effort. Unless obvious from the context or otherwise specified, the same reference numerals in the drawings represent the same structures or operations.

[0060] As indicated in this application and claims, unless the context clearly indicates otherwise, the words "a," "an," "an," and / or "the" are not specifically singular and may include plural forms. Generally speaking, the terms "comprising" and "including" only indicate the inclusion of explicitly identified steps and elements, which do not constitute an exclusive list, and the method or apparatus may also include other steps or elements.

[0061] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of this application. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following drawings denote similar items; therefore, once an item is defined in one drawing, it need not be further discussed in subsequent drawings.

[0062] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, these terms have no special meaning and therefore should not be construed as limiting the scope of protection of this application. In addition, although the terminology used in this application is selected from commonly known and used terms, some terms mentioned in this application's specification may have been chosen by the applicant according to his or her judgment, and their detailed meanings are explained in the relevant sections of this description. Moreover, this application should be understood not only through the actual terms used, but also through the meaning implied by each term.

[0063] See Figure 1 As shown, the target group observation method, method, and apparatus based on SAR satellites provided in this application can be applied to SAR satellite systems, which at least include: control equipment and a corresponding SAR satellite. The control equipment and the SAR satellite have a communication link. The SAR satellite operates in level flight mode during on-orbit operation, with the normal to its phased array antenna plane pointing towards the platform's nadir. Before target group observation, the SAR satellite can perform zero-Doppler guidance by adjusting its attitude or the phased array antenna beam pointing in real time.

[0064] The operations performed by the system according to an embodiment of this application will now be described with reference to a flowchart. It should be understood that the preceding or following operations are not necessarily performed in exact order. Instead, various steps can be processed in reverse order or simultaneously. Furthermore, other operations may be added to these processes, or one or more steps may be removed from these processes.

[0065] See Figure 2 The diagram shown is a flowchart of a target swarm observation method based on SAR satellites provided in this application. This flowchart is illustrated using the control equipment in the aforementioned SAR satellite system as the executing entity, and includes:

[0066] S201, Obtain the first key information of the target group to be observed and the second key information of the SAR satellites identified for the target group to be observed.

[0067] The first key information includes at least the geographical location of the area to be observed corresponding to the target group, and the second key information includes at least the orbital altitude of the SAR satellite, the speed of the SAR satellite relative to the ground, and the payload imaging control parameters of the SAR satellite.

[0068] S202, based on the first key information and the second key information, determine the maximum azimuth angle of the SAR satellite, and generate the attitude adjustment scheme of the SAR satellite based on the maximum azimuth angle.

[0069] Among them, the maximum azimuth angle is used to characterize the maximum pitch angle that the SAR satellite can image relative to the area to be observed. The attitude adjustment scheme includes at least the initial time and the end time set for the maximum azimuth angle, as well as the attitude adjustment angular velocity between the initial time and the end time.

[0070] For example, suppose the maximum azimuth angle determined based on the first key information and the second key information is θ. az_max In the attitude adjustment scheme, the initial time can be set to T0 corresponding to the maximum azimuth oblique angle.

[0071] In one optional implementation, the attitude adjustment scheme for generating SAR satellites based on the maximum azimuth oblique angle includes obtaining the cutoff time and attitude adjustment angular velocity in any of the following ways:

[0072] Method 1

[0073] Specifically, method 1 includes the following steps:

[0074] (1) The attitude adjustment time of the SAR satellite is calculated using the following formula:

[0075]

[0076] Among them, T a R represents the attitude adjustment time. e H0 represents the Earth's radius, H0 represents the orbital altitude of the SAR satellite, and φ represents the Earth's radius. p V represents the maximum oblique angle in the azimuth dimension. s This indicates the speed of the SAR satellite relative to the ground.

[0077] (2) Determine the corresponding cutoff time and attitude adjustment angular velocity based on the initial time and attitude adjustment duration set according to the corresponding maximum azimuth oblique angle, wherein the expression for the attitude adjustment angular velocity is:

[0078] For example, such as Figure 3 As shown, when a SAR satellite is set to adjust its attitude at a constant speed, according to the attitude adjustment scheme, at the initial time T0, the SAR satellite needs to adjust the elevation angle of the satellite platform to φ. p =θ az_max The cutoff time is calculated using method 1 as (T0+T). a If, at that deadline, the SAR satellite needs to adjust the elevation angle of the satellite platform to -φ, then... p =-θ az_max At some intermediate moment between the initial and final moments, the attitude of the SAR satellite is parallel to its orbit. At this moment, the downward angle of the SAR satellite relative to the center point of the area to be observed is the angle between the orbital normal of the SAR satellite and the line connecting its nadir point trajectory, denoted as θ0.

[0079] Method 2

[0080] Specifically, method 2 includes the following steps:

[0081] (1) The attitude adjustment time of the SAR satellite is calculated using the following formula:

[0082]

[0083] Among them, T a_l R represents the attitude adjustment time. e H0 represents the Earth's radius, H0 represents the orbital altitude of the SAR satellite, and φ represents the Earth's radius. p V represents the maximum oblique angle in the azimuth dimension. s W represents the orbital speed of a SAR satellite relative to the ground. az The length of the region to be observed along the track direction is denoted as .

[0084] (2) Determine the corresponding cutoff time and attitude adjustment angular velocity based on the initial time and attitude adjustment duration set according to the corresponding maximum azimuth oblique angle, wherein the expression for the attitude adjustment angular velocity is:

[0085] For example, such as Figure 4 As shown, when a SAR satellite is set to adjust its attitude at a constant speed, according to the attitude adjustment scheme, at the initial time T0, the SAR satellite needs to adjust the elevation angle of the satellite platform to φ. p =θ az_max The cutoff time is calculated using method 2 as (T0+T). a If, at that deadline, the SAR satellite needs to adjust the elevation angle of the satellite platform to -φ, then... p =-θ az_max At some intermediate moment between the initial and final moments, the attitude of the SAR satellite is parallel to its orbit. At this moment, the downward angle of the SAR satellite relative to the center point of the area to be observed is the angle between the orbital normal of the SAR satellite and the line connecting its nadir point trajectory, denoted as θ0.

[0086] It is understandable that, in practical applications, those skilled in the art can choose between Method 1 and Method 2 based on the actual situation of the target group to be observed. For example, when those skilled in the art determine that the target group to be observed is relatively concentrated along the track within the observation area and it is difficult to accurately measure the track length of the observation area, Method 1 can be selected to obtain the corresponding cutoff time and attitude adjustment angular velocity. Alternatively, when those skilled in the art determine that the target group to be observed is relatively dispersed along the track within the observation area and the track length of the observation area can be accurately measured, Method 2 can be selected to further extend the observation time of the SAR satellite. Furthermore, when other unforeseen circumstances occur that may require extending the observation time, those skilled in the art can also choose either Method 1 or Method 2 to be executed based on the circumstances. It should be understood that the execution of Method 1 or Method 2 is parallel, and this application does not impose specific restrictions on it.

[0087] S203, Based on the attitude adjustment scheme, generate an observation plan for the SAR satellite relative to the target group to be observed, and send the observation plan to the SAR satellite so that the SAR satellite can execute the observation plan. During the execution: from the initial time to the end time, adjust the pitch angle of the SAR satellite at least by the attitude adjustment angular velocity.

[0088] Based on the above method, the control equipment can initiate an observation plan to the SAR satellite, so that the SAR satellite can continuously control the attitude changes of the SAR satellite through the received observation plan, thereby enabling the antenna field of view to cover the designated target area for a longer period of time and improving the SAR satellite's ability to conduct single-flight dense observation of target groups in the area.

[0089] In one optional implementation, generating an observation plan for the SAR satellite relative to the target group based on an attitude adjustment scheme includes:

[0090] Step 1: Obtain the preset imaging task of the SAR satellite, wherein the preset imaging task includes at least: the preset azimuth beam pointing angle for the phased array antenna on the SAR satellite, and the preset range beam pointing angle for the phased array antenna.

[0091] Step 2: Perform scanning compensation on the preset azimuth beam pointing angle and the preset distance beam pointing angle to obtain the corresponding target azimuth beam pointing angle and target distance beam pointing angle.

[0092] Step 3: Generate the SAR satellite's observation plan relative to the target group based on the target azimuth beam pointing angle, target range beam pointing angle, and attitude adjustment scheme.

[0093] In one optional implementation, step 2 involves scanning and compensating the preset azimuth beam pointing angle and the preset range beam pointing angle to obtain the corresponding target azimuth beam pointing angle and target range beam pointing angle, including:

[0094] The following formulas are used to calculate the target azimuth beam pointing angle and target range beam pointing angle of the SAR satellite at each on-orbit time:

[0095] θ az_r (t)=sin -1 (x)

[0096] θ rg_r (t)=tan -1 (y / z)

[0097] in:

[0098]

[0099]

[0100] θ az_s θ represents the preset azimuth beam pointing angle. rg_s θ represents the preset distance-dimensional beam pointing angle. az_r (t) represents the target azimuth beam pointing angle at a given on-orbit moment, θ rg_r (t) represents the target range-dimensional beam pointing angle at a given on-orbit moment, φ p (t) represents the elevation angle of the SAR satellite at a given moment in orbit, φ y (t) represents the yaw angle of the SAR satellite at a given moment in orbit, φ r (t) represents the roll angle of the SAR at an on-orbit moment.

[0101] Based on the above method, SAR satellites can calculate the actual antenna beam pointing angle according to the preset antenna beam pointing angle and platform attitude angle information, and compensate for the preset antenna beam pointing angle during phased array antenna scanning [i.e., azimuth beam pointing angle compensation (θ)]. az_r (t)-θ az_s ), for range-dimensional beam pointing angle compensation (θ) rg_r (t)-θ rg_s This is to ensure stable beam pointing for target imaging and improve the stability of target group imaging observation.

[0102] In one alternative implementation, the control device may also perform the following steps before sending the observation plan to the SAR satellite:

[0103] A pre-adjustment command is sent to the SAR satellite so that the SAR satellite responds to the pre-adjustment command and adjusts the roll angle of the SAR satellite at a specified pre-adjustment time, wherein the pre-adjustment time is earlier than the initial time.

[0104] Based on the above method, the on-orbit attitude of the SAR satellite is pre-adjusted before the target group observation, so that the SAR satellite can adjust its roll angle to stably point to the center point of the area to be observed before the initial moment, thereby improving the stability of target group imaging observation.

[0105] like Figure 5 The diagram shown is a flowchart of a target group observation method provided in this application. This flowchart uses SAR satellites within a SAR satellite system as the implementing entity, and includes:

[0106] S501 receives the observation plan sent by the control equipment.

[0107] Among them: the observation plan is generated by the control equipment based on the attitude adjustment scheme, the attitude adjustment scheme is generated by the control equipment based on the maximum azimuth angle, the maximum azimuth angle is obtained by the control equipment based on the first key information of the target group to be observed and the second key information of the SAR satellite. The maximum azimuth angle is used to characterize: the maximum elevation angle that the SAR satellite can image relative to the area to be observed. The first key information includes at least: the geographical location of the area to be observed corresponding to the target group to be observed. The second key information includes at least: the orbital altitude of the SAR satellite, the motion speed of the SAR satellite relative to the ground, and the payload imaging control parameters of the SAR satellite. The attitude adjustment scheme includes at least: the initial time and the end time set for the maximum azimuth angle, and the attitude adjustment angular velocity between the initial time and the end time.

[0108] S502, Execute the observation plan to observe the target group. During the execution: from the initial time to the end time, adjust the elevation angle of the SAR satellite by at least the attitude adjustment angular velocity.

[0109] Based on the above method, SAR satellites can continuously control the attitude changes of SAR satellites according to the received observation plan, thereby enabling the antenna field of view to cover the designated target area for a longer period of time and improving the SAR satellite's ability to conduct single-flight dense observation of target groups in the area.

[0110] In an optional implementation, before receiving the observation plan sent by the control equipment, the SAR satellite can also adjust its roll angle at a specified pre-adjustment time in response to a pre-adjustment command sent by the control equipment, wherein the pre-adjustment time is earlier than the initial time. The SAR satellite can adjust its roll angle to stably point towards the center point of the area to be observed before the initial time, thereby improving the stability of subsequent target group imaging observations.

[0111] This invention provides two simulation verifications for the aforementioned target group observation method based on SAR satellites. The specific simulation conditions for the first simulation verification are as follows:

[0112] Earth's radius: 6378 km;

[0113] SAR satellite orbital altitude: 500km;

[0114] SAR satellite relative ground velocity: 7207 m / s;

[0115] Maximum azimuth angle of view: 45°;

[0116] Maximum distance dimension downward angle of view: 60°;

[0117] Phased array antenna azimuth scanning capability: ±10°, range scanning capability: ±35°;

[0118] The downward angle of the center point of the area to be observed is 35°.

[0119] The simulation results of the first simulation verification are as follows Figures 6a-6b As shown in the diagram, in this simulation, the SAR satellite will uniformly adjust its elevation angle from +45° to -45° at an attitude adjustment angular velocity of -0.58° / s. With the antenna distance-dimensional beam pointing angle at 35°, this ensures that the azimuth-dimensional beam pointing angle changes from +45° to -45°, synchronously following the platform's elevation angle change.

[0120] The specific simulation conditions for the second simulation verification are as follows:

[0121] Earth's radius: 6378 km;

[0122] SAR satellite orbital altitude: 500km;

[0123] SAR satellite relative ground velocity: 7207 m / s;

[0124] Maximum azimuth angle of view: 45°;

[0125] Maximum distance dimension downward angle of view: 60°;

[0126] Phased array antenna azimuth scanning capability: ±10°, range scanning capability: ±35°;

[0127] The downward angle of the center point of the area to be observed is 60°.

[0128] The simulation results of the second simulation verification are as follows Figures 7a-7b As shown in the diagram, in this simulation, the SAR satellite first adjusts its roll angle to 35°, and then uniformly adjusts its elevation angle from +45° to -45° using an attitude adjustment angular velocity (-0.58° / s). With an antenna distance-dimensional beam pointing angle of 60°, this ensures that the azimuth-dimensional beam pointing angle changes from +45° to -45°, synchronously following the platform's elevation angle change.

[0129] It can be seen that the simulation results above ensure that the antenna field of view can stably cover the target area for a long time, and that the actual range of the two-dimensional antenna beam pointing angle variation is within the electronic scanning capability of the phased array antenna. Therefore, the range of antenna beam pointing angle variation is large, which can effectively achieve scanning compensation. This method is truly effective in improving the single-flight dense observation capability of SAR satellites.

[0130] Further reading Figure 8 As shown, this application also provides a target swarm observation device based on SAR satellites. The device is installed in the control equipment of the SAR satellite system, and the device includes:

[0131] The key information acquisition module 801 is used to acquire first key information of the target group to be observed and second key information of the SAR satellite determined for the target group to be observed. The first key information includes at least the geographical location of the area to be observed corresponding to the target group to be observed. The second key information includes at least the orbital altitude of the SAR satellite, the motion speed of the SAR satellite relative to the ground, and the payload imaging control parameters of the SAR satellite.

[0132] The attitude adjustment scheme generation module 802 is used to determine the maximum azimuth angle of the SAR satellite based on the first key information and the second key information, and to generate an attitude adjustment scheme for the SAR satellite based on the maximum azimuth angle. The maximum azimuth angle is used to characterize the maximum pitch angle that the SAR satellite can image relative to the area to be observed. The attitude adjustment scheme includes at least the initial time and the end time set for the maximum azimuth angle, and the attitude adjustment angular velocity between the initial time and the end time.

[0133] The observation plan generation module 803 is used to generate an observation plan for the SAR satellite relative to the target group to be observed based on the attitude adjustment scheme, and send the observation plan to the SAR satellite so that the SAR satellite executes the observation plan. During the execution process, from the initial time to the end time, the pitch angle is adjusted at least by the attitude adjustment angular velocity.

[0134] In one optional implementation, the attitude adjustment scheme for the SAR satellite is generated based on the maximum azimuth oblique angle. The attitude adjustment scheme generation module 802 is used to obtain the cutoff time and the attitude adjustment angular velocity by performing the following steps:

[0135] The attitude adjustment time of the SAR satellite is calculated using the following formula:

[0136]

[0137] Among them, T a R represents the attitude adjustment time. e H0 represents the Earth's radius, H0 represents the orbital altitude of the SAR satellite, and φ represents the Earth's radius. p V represents the maximum azimuth angle of view. s This indicates the orbital speed of the SAR satellite relative to the ground;

[0138] Based on the initial time set according to the maximum azimuth oblique angle and the attitude adjustment duration, the corresponding cutoff time and attitude adjustment angular velocity are determined, wherein the expression for the attitude adjustment angular velocity is:

[0139] In one optional implementation, the attitude adjustment scheme for the SAR satellite is generated based on the maximum azimuth oblique angle, and the attitude adjustment scheme generation module 802 is used to obtain the cutoff time and the attitude adjustment angular velocity:

[0140] The attitude adjustment time of the SAR satellite is calculated using the following formula:

[0141]

[0142] Among them, T a_l R represents the attitude adjustment time. e H0 represents the Earth's radius, H0 represents the orbital altitude of the SAR satellite, and φ represents the Earth's radius. p V represents the maximum azimuth angle of view. s This indicates the orbital speed of the SAR satellite relative to the ground; W az The length of the region to be observed along the track direction;

[0143] Based on the initial time set according to the maximum azimuth oblique angle and the attitude adjustment duration, the corresponding cutoff time and attitude adjustment angular velocity are determined, wherein the expression for the attitude adjustment angular velocity is:

[0144] In one optional implementation, the observation plan generation module 803, which generates the observation plan of the SAR satellite relative to the target group based on the attitude adjustment scheme, is used to:

[0145] Obtain the preset imaging task of the SAR satellite, wherein the preset imaging task includes at least: a preset azimuth beam pointing angle for the phased array antenna carried by the SAR satellite, and a preset range beam pointing angle for the phased array antenna;

[0146] The preset azimuth beam pointing angle and the preset distance beam pointing angle are scanned and compensated to obtain the corresponding target azimuth beam pointing angle and target distance beam pointing angle.

[0147] The SAR satellite generates an observation plan relative to the target group based on the target azimuth beam pointing angle, the target range beam pointing angle, and the attitude adjustment scheme.

[0148] In an optional implementation, the step of scanning and compensating the preset azimuth beam pointing angle and the preset range beam pointing angle to obtain the corresponding target azimuth beam pointing angle and target range beam pointing angle, wherein the observation plan generation module 803 is used for:

[0149] The following formulas are used to calculate the corresponding target azimuth beam pointing angle and target range beam pointing angle of the SAR satellite at each on-orbit time:

[0150] θ az_r (t)=sin -1 (x)

[0151] θ rg_r (t)=tan -1 (y / z)

[0152] in:

[0153]

[0154]

[0155] θ az_s θ represents the preset azimuth beam pointing angle. rg_s θ represents the preset distance-dimensional beam pointing angle. az_r (t) represents the target azimuth beam pointing angle at a given on-orbit moment, θ rg_r (t) represents the target range beam pointing angle corresponding to a given on-orbit moment, φ p (t) represents the elevation angle of the SAR satellite at a given on-orbit moment, φ y (t) represents the yaw angle of the SAR satellite at a given on-orbit moment, φ r (t) represents the roll angle of the SAR at a given on-orbit time.

[0156] In an optional implementation, before sending the observation plan to the SAR satellite, the observation plan generation module 803 is further configured to:

[0157] A pre-adjustment command is sent to the SAR satellite so that the SAR satellite responds to the pre-adjustment command and adjusts the roll angle of the SAR satellite at a specified pre-adjustment time, wherein the pre-adjustment time is earlier than the initial time.

[0158] See Figure 9 As shown, this application also provides a target group observation device, which is installed on a SAR satellite in the SAR satellite system. The device includes:

[0159] The observation plan receiving module 901 is used to receive an observation plan sent by the control device, wherein: the observation plan is generated by the control device based on an attitude adjustment scheme, the attitude adjustment scheme is generated by the control device based on the maximum azimuth angle, the maximum azimuth angle is obtained by the control device based on the first key information of the target group to be observed and the second key information of the SAR satellite, the maximum azimuth angle is used to characterize: the maximum elevation angle that the SAR satellite can image relative to the area to be observed, the first key information includes at least: the geographical location of the area to be observed corresponding to the target group to be observed, the second key information includes at least: the orbital altitude of the SAR satellite, the motion speed of the SAR satellite relative to the ground, and the payload imaging control parameters of the SAR satellite, and the attitude adjustment scheme includes at least: the initial time and the end time set corresponding to the maximum azimuth angle, and the attitude adjustment angular velocity between the initial time and the end time;

[0160] The observation plan execution module 902 is used to execute the observation plan to observe the target group to be observed. During the execution process, from the initial time to the end time, the elevation angle of the SAR satellite is adjusted by the attitude adjustment angular velocity.

[0161] In an optional implementation, before the observation plan is sent by the receiving control device, the observation plan execution module 902 is further configured to:

[0162] In response to a pre-adjustment command sent by the control device, the roll angle of the SAR satellite is adjusted at a specified pre-adjustment time, wherein the pre-adjustment time is earlier than the initial time.

[0163] See Figure 10 This application also provides an electronic device, which includes:

[0164] Memory 1001; and,

[0165] The processor 1002, the memory 1001 stores instructions, and when the instructions are invoked by the processor, the processor executes the steps of any of the SAR-based target group observation methods or target group observation methods described above.

[0166] It should be understood that the processor mentioned in the embodiments of this application can be a CPU, or other general-purpose processors, DSPs, ASICs, FPGAs, or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor can be a microprocessor or any conventional processor.

[0167] It should also be understood that the memory mentioned in the embodiments of this application can be volatile memory or non-volatile memory, or may include both volatile and non-volatile memory. Non-volatile memory can be read-only memory (ROM), programmable read-only memory, erasable programmable read-only memory, electrically erasable programmable read-only memory, or flash memory. Volatile memory can be random access memory (RAM), which is used as an external cache. By way of example, but not limitation, many forms of RAM are available, such as static random access memory, dynamic random access memory, synchronous dynamic random access memory, double data rate synchronous dynamic random access memory, enhanced synchronous dynamic random access memory, synchronous linked dynamic random access memory, and direct memory bus random access memory.

[0168] It should be noted that when the processor is a general-purpose processor, DSP, ASIC, FPGA, or other programmable logic device, discrete gate or transistor logic device, or discrete hardware component, the memory (storage module) is integrated into the processor.

[0169] This application also provides a computer-readable medium having computer program code stored thereon, which, when executed by the processor described above, implements any of the SAR-based target group observation methods or target group observation methods mentioned above.

[0170] The basic concepts have been described above. Obviously, for those skilled in the art, the above disclosure is merely illustrative and does not constitute a limitation of this application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements, and corrections to this application. Such modifications, improvements, and corrections are suggested in this application, and therefore remain within the spirit and scope of the exemplary embodiments of this application.

[0171] Furthermore, this application uses specific terms to describe embodiments of the application. For example, "an embodiment," "one embodiment," and / or "some embodiments" refer to a particular feature, structure, or characteristic related to at least one embodiment of the application. Therefore, it should be emphasized and noted that "an embodiment," "one embodiment," or "an alternative embodiment" mentioned twice or more in different locations in this specification do not necessarily refer to the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of the application can be appropriately combined.

[0172] Some aspects of this application can be executed entirely by hardware, entirely by software (including firmware, resident software, microcode, etc.), or by a combination of hardware and software. The aforementioned hardware or software may be referred to as a "data block," "module," "engine," "unit," "component," or "system." The processor may be one or more application-specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DAPDs), programmable logic devices (PLDs), field-programmable gate arrays (FPGAs), processors, controllers, microcontrollers, microprocessors, or combinations thereof. Furthermore, aspects of this application may manifest as computer products residing in one or more computer-readable media, including computer-readable program code. For example, computer-readable media may include, but are not limited to, magnetic storage devices (e.g., hard disks, floppy disks, magnetic tapes, etc.), optical discs (e.g., compressed CDs, digital multifunction DVDs, etc.), smart cards, and flash memory devices (e.g., cards, sticks, key drives, etc.).

[0173] A computer-readable medium may contain a propagated data signal containing computer program code, for example, on baseband or as part of a carrier wave. This propagated signal may take various forms, including electromagnetic, optical, and so on, or suitable combinations thereof. A computer-readable medium can be any computer-readable medium other than a computer-readable storage medium, which can be connected to an instruction execution system, apparatus, or device to enable communication, propagation, or transmission of a program for use. The program code located on the computer-readable medium can be propagated through any suitable medium, including radio, cable, fiber optic cable, radio frequency signals, or similar media, or any combination of the above media.

[0174] Similarly, it should be noted that, in order to simplify the description of the present application and thus aid in the understanding of one or more embodiments of the invention, the foregoing description of the embodiments of the present application sometimes combines multiple features into a single embodiment, drawing, or description thereof. However, this disclosure method does not imply that the subject matter of the application requires more features than those mentioned in the claims. In fact, the embodiments contain fewer features than all the features of the single embodiments disclosed above.

[0175] In some embodiments, numbers describing the quantity of components and attributes are used. It should be understood that such numbers used in the description of embodiments are modified in some examples with the terms "approximately," "approximately," or "generally." Unless otherwise stated, "approximately," "approximately," or "generally" indicates that the numbers are allowed to vary by ±20%. Accordingly, in some embodiments, the numerical parameters used in the specification and claims are approximate values, which may be changed depending on the characteristics required by individual embodiments. In some embodiments, numerical parameters should take into account specified significant digits and employ a general method of digit reservation. Although the numerical ranges and parameters used to confirm their breadth of scope in some embodiments of this application are approximate values, in specific embodiments, such values ​​are set as precisely as feasible.

[0176] Although this application has been described with reference to specific embodiments, those skilled in the art should recognize that the above embodiments are only used to illustrate this application, and various equivalent changes or substitutions can be made without departing from the spirit of this application. Therefore, any changes or modifications to the above embodiments within the essential spirit of this application will fall within the scope of the claims of this application.

Claims

1. A method for observing a target group based on a SAR satellite, characterized in that, The method is applied to a control device in a SAR satellite system, and comprises the following steps: obtaining first key information of a target group to be observed and second key information of a SAR satellite determined for the target group to be observed, wherein the first key information at least includes a geographical position of a target area to be observed corresponding to the target group to be observed, and the second key information at least includes an orbit height of the SAR satellite, a moving speed of the SAR satellite relative to the ground, and a load imaging control parameter of the SAR satellite; determining a maximum azimuth dimension squint angle of the SAR satellite based on the first key information and the second key information, and generating an attitude adjustment scheme of the SAR satellite based on the maximum azimuth dimension squint angle, wherein the maximum azimuth dimension squint angle is used to represent a maximum pitch angle at which the SAR satellite can image relative to the target area to be observed, and the attitude adjustment scheme at least includes an initial time point corresponding to the maximum azimuth dimension squint angle, a cutoff time point, and an attitude adjustment angular velocity between the initial time point and the cutoff time point; generating an observation plan of the SAR satellite relative to the target group to be observed based on the attitude adjustment scheme, and sending the observation plan to the SAR satellite, so that the SAR satellite executes the observation plan, and in the execution process, at least the pitch angle of the SAR satellite is adjusted at the attitude adjustment angular velocity from the initial time point to the cutoff time point.

2. The method of claim 1, wherein, The method for generating the attitude adjustment scheme of the SAR satellite based on the maximum azimuth dimension squint angle comprises obtaining the cutoff time point and the attitude adjustment angular velocity in the following manner: The attitude adjustment time length of the SAR satellite is calculated by using the following formula: wherein, denotes the attitude adjustment duration, denotes the earth radius, denotes the orbit height of the SAR satellite, denotes the maximum azimuth dimension, denotes the running speed of the SAR satellite relative to the ground; Determine the corresponding cut-off time and the attitude adjustment angular velocity based on the initial time corresponding to the maximum azimuthal visual angle setting and the attitude adjustment time length, wherein the expression of the attitude adjustment angular velocity is: .

3. The method of claim 1, wherein, The method for generating the attitude adjustment scheme of the SAR satellite based on the maximum azimuth dimension squint angle comprises obtaining the cutoff time point and the attitude adjustment angular velocity in the following manner: The attitude adjustment time length of the SAR satellite is calculated by using the following formula: wherein, represents the posture adjustment duration, represents the radius of the earth, represents the orbit height of the SAR satellite, represents the maximum azimuth dimension, represents the running speed of the SAR satellite relative to the ground; is the along-track length of the region to be observed; Determine the corresponding cut-off time and the attitude adjustment angular velocity based on the initial time corresponding to the maximum azimuthal visual angle setting and the attitude adjustment time length, wherein the expression of the attitude adjustment angular velocity is: .

4. The method of claim 1, wherein, The method for generating the observation plan of the SAR satellite relative to the target group to be observed based on the attitude adjustment scheme comprises the following steps: obtaining a preset imaging task of the SAR satellite, wherein the preset imaging task at least includes a preset azimuth dimension beam pointing angle of a phased array antenna carried by the SAR satellite, and a preset range dimension beam pointing angle of the phased array antenna; performing scan compensation on the preset azimuth dimension beam pointing angle and the preset range dimension beam pointing angle to obtain a target azimuth dimension beam pointing angle and a target range dimension beam pointing angle; generating the observation plan of the SAR satellite relative to the target group to be observed based on the target azimuth dimension beam pointing angle, the target range dimension beam pointing angle, and the attitude adjustment scheme.

5. The method of claim 4, wherein, The method for performing scan compensation on the preset azimuth dimension beam pointing angle and the preset range dimension beam pointing angle to obtain a target azimuth dimension beam pointing angle and a target range dimension beam pointing angle comprises the following steps: The target azimuth dimension beam pointing angle and the target range dimension beam pointing angle of the SAR satellite at each in-orbit time point are calculated by using the following formula: wherein: denotes the preset azimuth dimension beam pointing angle, denotes the preset range dimension beam pointing angle, denotes the target azimuth dimension beam pointing angle corresponding to one on-orbit time, denotes the target range dimension beam pointing angle corresponding to one on-orbit time, denotes the pitch angle of the SAR satellite at the one on-orbit time, denotes the yaw angle of the SAR satellite at the one on-orbit time, denotes the roll angle of the SAR at the one on-orbit time.

6. The method of claim 1, wherein, The method further includes, before sending the observation plan to the SAR satellite: sending a pre-adjustment instruction to the SAR satellite, so that the SAR satellite adjusts a roll angle of the SAR satellite at a specified pre-adjustment time in response to the pre-adjustment instruction, wherein the pre-adjustment time is earlier than the initial time.

7. A target group observation method characterized by comprising: The method is applied to a SAR satellite in a SAR satellite system, and the method includes: receiving an observation plan sent by a control device, wherein the observation plan is generated by the control device based on an attitude adjustment scheme, the attitude adjustment scheme is generated by the control device based on a maximum azimuth dimension squint angle, the maximum azimuth dimension squint angle is obtained by the control device based on first key information of a target group to be observed and second key information of the SAR satellite, the maximum azimuth dimension squint angle is used to represent a maximum pitch angle of the SAR satellite relative to an observation area, the first key information at least includes a geographical position of an observation area corresponding to the target group to be observed, and the second key information at least includes an orbit height of the SAR satellite, a movement speed of the SAR satellite relative to the ground, and a load imaging control parameter of the SAR satellite, and the attitude adjustment scheme at least includes an initial time corresponding to the maximum azimuth dimension squint angle, a cutoff time, and an attitude adjustment angular velocity between the initial time and the cutoff time; performing observation on the target group to be observed according to the observation plan, and during the performance, the pitch angle of the SAR satellite is adjusted at least at the attitude adjustment angular velocity from the initial time to the cutoff time.

8. The method of claim 7, wherein, The method further includes, before receiving the observation plan sent by the control device: adjusting a roll angle of the SAR satellite at a specified pre-adjustment time in response to a pre-adjustment instruction sent by the control device, wherein the pre-adjustment time is earlier than the initial time.

9. A target swarm observation device based on SAR satellites, characterized in that, The device is arranged in a control device in a SAR satellite system, and the device includes: a key information acquisition module configured to acquire first key information of a target group to be observed and second key information of a SAR satellite determined for the target group to be observed, wherein the first key information at least includes a geographical position of an observation area corresponding to the target group to be observed, and the second key information at least includes an orbit height of the SAR satellite, a movement speed of the SAR satellite relative to the ground, and a load imaging control parameter of the SAR satellite; an attitude adjustment scheme generation module configured to determine a maximum azimuth dimension squint angle of the SAR satellite based on the first key information and the second key information, and generate an attitude adjustment scheme of the SAR satellite based on the maximum azimuth dimension squint angle, wherein the maximum azimuth dimension squint angle is used to represent a maximum pitch angle of the SAR satellite relative to the observation area, and the attitude adjustment scheme at least includes an initial time corresponding to the maximum azimuth dimension squint angle, a cutoff time, and an attitude adjustment angular velocity between the initial time and the cutoff time. An observation plan generation module is configured to generate an observation plan of the SAR satellite relative to the target group to be observed based on the attitude adjustment scheme, and send the observation plan to the SAR satellite, so that the SAR satellite executes the observation plan, and in the execution process, the pitch angle is adjusted at least at the attitude adjustment angular velocity from the initial time to the cutoff time.

10. A target group observation device characterized by comprising: The device is arranged in a SAR satellite system, and the device comprises: An observation plan receiving module is configured to receive an observation plan sent by a control device, wherein the observation plan is generated by the control device based on an attitude adjustment scheme, the attitude adjustment scheme is generated by the control device based on a maximum azimuth dimension squint angle, the maximum azimuth dimension squint angle is obtained by the control device based on first key information of a target group to be observed and second key information of the SAR satellite, the maximum azimuth dimension squint angle is used to represent a maximum pitch angle of the SAR satellite relative to a to-be-observed area, the first key information at least includes a geographical position of a to-be-observed area corresponding to the target group to be observed, and the second key information at least includes an orbit height of the SAR satellite, a movement speed of the SAR satellite relative to the ground, and a load imaging control parameter of the SAR satellite, and the attitude adjustment scheme at least includes an initial time corresponding to the maximum azimuth dimension squint angle, a cutoff time, and an attitude adjustment angular velocity between the initial time and the cutoff time; An observation plan execution module is configured to execute the observation plan to observe the target group to be observed, and in the execution process, the pitch angle of the SAR satellite is adjusted at the attitude adjustment angular velocity from the initial time to the cutoff time.

11. An electronic device, comprising: comprises: a memory; and a processor; The memory stores instructions executable by the processor, and the processor implements the target group observation method based on the SAR satellite according to any one of claims 1-5, or implements the target group observation method according to any one of claims 6-8.

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