A remote sensing satellite point target real shooting real transmission prediction analysis method

Abstract

A method for predicting and analyzing the real-time image transmission capability of remote sensing satellite point targets belongs to the field of satellite mission planning and data transmission technology. Without relying on third-party simulation software, it achieves automated analysis of the real-time image transmission capability of point targets through geometric analysis under imaging attitude and joint determination of time windows. It is used to automatically determine whether a ground point target meets the condition of "real-time image transmission after imaging" under the condition that the satellite imaging attitude is not adjusted, comprehensively considering the satellite imaging attitude, phased array antenna beam scanning angle limitations, and imaging-to-data transmission time constraints. This avoids reliance on manual simulation and calculation, improving analysis efficiency and accuracy.

Description

Technical Field

[0001] This invention belongs to the field of satellite mission planning and data transmission technology, specifically relating to a method for forecasting and analyzing real-time images and transmissions of remote sensing satellite point targets. Background Technology

[0002] With the increasing number of low-orbit remote sensing satellites and the ever-increasing demands for data timeliness in application scenarios, higher requirements are being placed on the ability to coordinate the use of imaging and data transmission resources during satellite mission execution.

[0003] In some high-time-efficiency application scenarios, satellites need to transmit the imaging data back to the ground station as soon as possible while completing the imaging of the earth, so as to reduce the delay caused by data storage on the satellite, thereby realizing the "real-time shooting and transmission" business model.

[0004] In practical engineering applications, satellites typically use phased array antennas for data transmission. In non-imaging mode, the satellite can adjust its attitude to ensure that the phased array antenna is always pointing towards the ground station, forming a so-called staring attitude. At this time, the ground station is within the main lobe range of the antenna and can obtain the maximum available arc for data transmission.

[0005] However, when performing Earth imaging missions, the satellite attitude must meet imaging geometric constraints, and the pointing direction of the phased array antenna must remain consistent with the imaging attitude, making it impossible to independently align it with the ground station. In this case, whether the ground station is within the effective radiation range of the phased array antenna depends on the relative position of the satellite's imaging attitude and the ground station, and its available data transmission time window will be significantly smaller compared to the staring attitude.

[0006] Furthermore, imaging data onboard must undergo storage, processing, and data retrieval by the data transmission module. Data transmission cannot begin immediately after imaging, further compressing the time window available for live imaging and transmission. Therefore, accurately determining whether a specific ground target can be captured and transmitted under limited data transmission conditions, given its imaging attitude, becomes a key technical issue in satellite mission planning and forecasting analysis. Summary of the Invention

[0007] To address the aforementioned technical problems, this invention provides a method for forecasting and analyzing real-time images and transmissions of remote sensing satellite point targets, specifically as follows: S1. Acquisition of imaging geometric parameters: including imaging start time ts, imaging time tm, and imaging end time te; S2. Imaging Data Volume Calculation: Calculate the amount of data generated by the imaging of point targets; S3. Data transmission duration calculation: Calculate the data transmission duration t_receiving_duration required to complete the imaging data based on the data transmission rate between the satellite and the ground station; S4. Determining the earliest possible data transmission time: The earliest possible data transmission time receivingStartTime = ts + t_threshold, where t_threshold is a time parameter representing the inherent delay; S5. Calculation of data transmission end time: data transmission end time receivingStopTime = receivingStartTime + t_receiving_duration; S6. Data transmission window calculation under staring attitude: Under the condition that the satellite is in staring attitude and the phased array antenna is always pointing to the ground station, calculate the data transmission start time Rs and data transmission end time Re between the satellite and the ground station; S7. Beam scanning angle parameter setting: Set the maximum allowable beam scanning angle A of the phased array antenna; S8. Initial screening of beam scanning angle at imaging time: Calculate the beam scanning angle θ between the phased array antenna normal direction and the ground station direction at imaging time tm. If θ > A, the target at that point cannot transmit data under the imaging attitude and is directly determined not to meet the requirements of real shooting and transmission. If θ ≤ A, proceed to step S9. S9. Starting from the imaging time tm, loop backward according to the preset time step Δt: Calculate the corresponding beam scanning angle θ_now at each time step. When θ_now>A for the first time... Record the previous moment as the latest possible data transmission moment t_max, and end the search; S10. Validity judgment of the latest available data transmission time: If t_max is not found, it is determined that the target at this point does not meet the requirements of real shooting and real transmission; S11. Beam scanning angle and data transmission completion time constraint judgment: If t_max exists, then judge: t_max ≥ receivingStopTime, and proceed to step S12; If the requirements are not met, it means that the imaging data has not been transmitted and the beam scanning angle has exceeded the allowable range, thus failing to meet the requirements for real-time shooting and transmission. S12. Staring attitude data transmission window constraint judgment: Further judgment is made that receivingStopTime ≤ Re. If it is not satisfied, it means that the imaging data has not been transmitted and the satellite has left the data transmission window under the staring attitude. The judgment fails and the requirement of real shooting and transmission is not met. S13. Result determination: Point targets that simultaneously satisfy steps S11 and S12 are determined to be imageable point targets that meet the requirements of real-time shooting and transmission.

[0008] The beneficial effects of the method described in this invention are as follows: In existing technologies, the analysis of satellite imagery and transmission capabilities typically relies on commercial satellite orbit and mission simulation software. For example, by inputting satellite orbital elements, ground station parameters, and ground target information, and setting satellite attitude and antenna parameters, the feasibility of data transmission is analyzed using a second-by-second simulation method. This type of approach generally includes the following steps: Establish satellite orbit and ground station model; Establish a ground point target model; Set the imaging attitude, antenna pointing and data transmission angle parameters; The available arc segment for data transmission is obtained through high time resolution simulation; The amount of imaging data and the time required for data transmission are calculated manually. The calculation results are manually compared with the simulation results to determine whether they meet the requirements for real-time shooting and transmission.

[0009] The above solution has the following shortcomings in practical applications: 1. The analysis process is complex and requires a high degree of human intervention. The process of manually building models, configuring parameters, and comparing results is cumbersome and difficult to support large-scale or high-frequency analysis tasks.

[0010] 2. Low analysis efficiency, making it difficult to quickly respond to task requirements. The computational load of second-by-second simulation is large, and it is difficult to provide analysis results in a timely manner when facing multiple target points or multiple task planning adjustments.

[0011] 3. High dependence on third-party simulation software The analysis process is highly dependent on external commercial software, making it difficult to achieve automated integration and large-scale deployment within business systems.

[0012] 4. Results are easily affected by human factors. Data transmission duration, attitude changes, and window clipping are often calculated manually or judged based on experience, which can easily introduce errors and affect the reliability of the analysis results.

[0013] Therefore, existing technologies struggle to meet the requirements of automation, real-time performance, and engineering feasibility in live-action shooting and transmission scenarios while ensuring analytical accuracy.

[0014] To address the aforementioned issues, the method described in this invention proposes a real-time image and transmission prediction analysis method for remote sensing satellite point targets. Without relying on third-party simulation software, it achieves automated analysis of the real-time image and transmission capability of point targets through geometric analysis of imaging attitude and joint determination of time windows.

[0015] Compared with traditional solutions, the method described in this invention has the following technical advantages: 1. Shifting from gaze posture assumptions to realistic modeling of imaging posture The method described in this invention is based directly on the satellite imaging attitude analysis, and fully considers the beam scanning angle change of the phased array antenna in the imaging state, thus avoiding the problem that the staring attitude assumption in the traditional scheme is inconsistent with the actual imaging conditions.

[0016] 2. Introduce a dynamic determination mechanism for beam scanning angle constraints. By calculating the phased array antenna beam scanning angle time-by-time, the effective data transmission time interval that meets the beam scanning angle limit is automatically determined, thereby enabling accurate judgment of the feasibility of data transmission.

[0017] 3. Joint Constraint Analysis of Imaging-Data Transmission Time Window The method described in this invention comprehensively considers imaging data processing delay, data transmission duration, and data transmission window under staring posture to jointly determine whether the data transmission process can be completed completely, and the analysis results are more in line with engineering practice.

[0018] 4. Achieve fully automated analysis and reduce manual intervention. The method described in this invention only requires input of satellite and imaging time information to automatically output whether the point target meets the requirements of real-time shooting and transmission, significantly reducing human intervention and improving analysis efficiency.

[0019] 5. Easy system integration and batch expansion The method described in this invention employs a clear calculation process and judgment logic, which facilitates programmatic deployment in business systems and provides a foundation for subsequent expansion to regional-level live-action shooting and transmission analysis. Attached Figure Description

[0020] Figure 1 This is a schematic diagram illustrating the beam scanning angle calculation in an embodiment of the present invention. Detailed Implementation

[0021] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0022] Example 1 This embodiment proposes a method for predicting and analyzing real-time images and transmissions of remote sensing satellite point targets. This method is used to automatically determine whether a certain ground point target meets the condition of "real-time image and transmission can be completed after imaging" under the condition that the satellite imaging attitude is not adjusted, taking into account the satellite imaging attitude, the beam scanning angle limitation of the phased array antenna, and the imaging-data transmission time constraint. This avoids relying on manual simulation and calculation, and improves the efficiency and accuracy of analysis.

[0023] Overall Approach Taking point target imaging as the analysis object, based on the satellite orbit and imaging geometric parameters, the following is introduced: the maximum allowable beam scanning angle constraint of the phased array antenna is introduced; the time interval for data transmission is searched under the imaging attitude; and the following is jointly judged: whether the imaging data can be transmitted within the allowable beam scanning angle, and whether the data transmission process falls completely within the data transmission window under the staring attitude; thus, the judgment result of whether the point target meets the conditions for real-time shooting and transmission is given.

[0024] Specific steps: S1. Acquisition of imaging geometric parameters: including imaging start time ts, imaging time tm, imaging end time te, satellite roll angle at imaging time, satellite position coordinates (X,Y,Z) in WGS84 coordinate system at imaging time, and satellite velocity components (V) at imaging time. x V y V z ).

[0025] S2. Calculation of imaging data volume: Calculate the amount of data generated by point target imaging; The amount of data generated by point target imaging = the amount of imaging data per second by the camera × (te-ts).

[0026] S3. Data transmission duration calculation: Calculate the data transmission duration t_receiving_duration required to complete the imaging data based on the data transmission rate between the satellite and the ground station; S4. Determining the earliest possible data transmission time: The earliest possible data transmission time receivingStartTime = ts + t_threshold, where t_threshold is a time parameter representing the inherent delay; S5. Calculation of data transmission end time: data transmission end time receivingStopTime = receivingStartTime + t_receiving_duration; S6. Data transmission window calculation under staring attitude: Under the condition that the satellite is in staring attitude and the phased array antenna is always pointing to the ground station, calculate the data transmission start time Rs and data transmission end time Re between the satellite and the ground station; S7. Beam scanning angle parameter setting: Set the maximum allowable beam scanning angle A of the phased array antenna; S8. Initial screening of beam scanning angle at imaging time: Calculate the beam scanning angle θ between the phased array antenna normal direction and the ground station direction at imaging time tm. If θ > A, the target at that point cannot transmit data under the imaging attitude and is directly determined not to meet the requirements of real shooting and transmission. If θ ≤ A, proceed to step S9. S9. Starting from the imaging time tm, loop backward according to the preset time step Δt: Calculate the corresponding beam scanning angle θ_now at each time step. When θ_now>A for the first time... Record the previous moment as the latest possible data transmission moment t_max, and end the search; S10. Validity judgment of the latest available data transmission time: If t_max is not found, it is determined that the target at this point does not meet the requirements of real shooting and real transmission; S11. Beam scanning angle and data transmission completion time constraint judgment: If t_max exists, then judge: t_max ≥ receivingStopTime, and proceed to step S12; If the requirements are not met, it means that the imaging data has not been transmitted and the beam scanning angle has exceeded the allowable range, thus failing to meet the requirements for real-time shooting and transmission. S12. Staring attitude data transmission window constraint judgment: Further judgment is made that receivingStopTime ≤ Re. If it is not satisfied, it means that the imaging data has not been transmitted and the satellite has left the data transmission window under the staring attitude. The judgment fails and the requirement of real shooting and transmission is not met. S13. Result determination: Point targets that simultaneously satisfy steps S11 and S12 are determined to be imageable point targets that meet the requirements of real-time shooting and transmission.

[0027] Example 2 like Figure 1 As shown, the beam scanning angle θ of a satellite phased array antenna is defined as: The angle between the pointing vector of the satellite at a certain roll angle and the spatial vector pointing from the satellite's current position to the ground station's position.

[0028] Under satellite imaging attitude, the pointing direction of the phased array antenna remains consistent with the imaging attitude, and no independent pointing adjustment is performed. Therefore, the beam scanning angle changes over time.

[0029] By calculating the angle between the two vectors, the beam scanning angle θ at any given moment can be obtained. When the beam scanning angle θ is less than or equal to the maximum allowable beam scanning angle A of the phased array antenna, the ground station is within the effective radiation range of the phased array antenna and can transmit data; when the beam scanning angle θ is greater than A, the ground station is outside the effective radiation range and cannot transmit data.

[0030] This method calculates the beam scanning angle time-by-time under the imaging posture to determine the effective data transmission time interval that satisfies the beam scanning angle constraint, providing a geometric constraint basis for determining the feasibility of real-time shooting and transmission of point targets.

[0031] First, we will introduce the calculation of ground intersection points under satellite side-swing conditions: Obtain the satellite's position coordinates in the WGS-84 geocentric-ground-fixed coordinate system. and velocity components : and side swing angle and front and rear swing angles .

[0032] (1) Establishment of the satellite orbit coordinate system Radial unit vector from the satellite to the Earth's center:

[0033] Considering the Earth's rotational angular velocity The velocity component caused by Earth's rotation:

[0034] Lateral unit vector of the track:

[0035] Forward unit vector of the orbit:

[0036] Construct the transformation matrix from the orbital coordinate system to the Earth-centered Earth-fixed coordinate system:

[0037] The transformation matrix consists of three orthogonal unit basis vectors of the satellite's instantaneous orbital coordinate system. Its column vectors represent the direction cosines of the orbital coordinate axes in the geocentric-geocentric coordinate system. This matrix enables a linear coordinate transformation from the orbital coordinate system to the geocentric-geocentric coordinate system.

[0038] This transformation matrix is ​​essentially equivalent to expressing the satellite's front, side, and bottom directions using the XYZ components of Earth's fixed coordinates.

[0039] (2) Attitude rotation matrix The attitude rotation matrix is ​​constructed from the side sway angle and the front and rear sway angles:

[0040] in:

[0041]

[0042] This is the identity matrix, which uses a three-axis Euler angle representation in attitude transformation, with the rotation order being ZYX. Since this embodiment does not involve yaw attitude control, the yaw angle is set to zero, and its corresponding rotation matrix is ​​the identity matrix. This item is used to maintain the complete three-axis representation of the attitude model so that it can be extended to cases that include yaw control in the future.

[0043] (3) Calculation of line of sight direction The sensor's line of sight is defined in its own coordinate system as:

[0044] The direction vector of the line of sight in the Earth-centered, Earth-fixed coordinate system:

[0045] (4) Earth ellipsoid model The Earth ellipsoid is defined as:

[0046] in The radius is the equatorial radius. is the polar radius.

[0047] (5) Solving for the intersection of the line of sight and the ellipsoid Line of sight equation:

[0048] in, This indicates the distance the satellite has moved along the observation direction. This indicates the spatial location point corresponding to that distance.

[0049] By substituting the ray equation representing the direction of satellite observation into the Earth ellipsoid equation, the spatial geometric intersection problem can be transformed into a problem of solving a quadratic equation about the path parameters, thereby obtaining the intersection point between the line of sight and the Earth's surface.

[0050] We obtain the quadratic equation:

[0051] in:

[0052]

[0053]

[0054] in, These represent the directional components of the sensor's line of sight in the WGS-84 geocentric coordinate system. These represent the satellite's position coordinates in the WGS-84 geocentric-ground-fixed coordinate system.

[0055] Take the satisfaction The smallest real root: Intersection coordinates: .

[0056] Because Algorithm 1 will eventually provide two satellite positions, and Algorithm 2 will be called based on these two satellite positions, thus obtaining two intersection points.

[0057] (6) Calculation of the latitude and longitude of the intersection point Eccentricity:

[0058] longitude:

[0059] latitude: ,in, .

[0060] The specific method for calculating the beam scanning angle is as follows: The input data is: the satellite's position in the WGS-84 coordinate system. With speed

[0061] Side swing angle

[0062] Latitude and longitude of the ground station

[0063] Output: Angle formed by satellite, imaging point, and ground station That is, the beam scanning angle.

[0064] (1) Calculation of imaging points under lateral swing conditions Calculate the latitude and longitude of the corresponding ground imaging point based on the satellite's position, velocity, and roll angle:

[0065] in This describes the process of calculating the imaging point based on the intersection of the line of sight and the Earth's ellipsoid, which is the calculation process of Algorithm 2. and These represent the satellite's position and velocity in the WGS-84 geocentric coordinate system at a given moment.

[0066] (2) Conversion from latitude and longitude to geocentric coordinates Image point With the target point Convert from latitude and longitude to WGS-84 geocentric coordinates:

[0067]

[0068] (3) Calculation of spatial distance between three points Calculate the Euclidean distance between three points:

[0069]

[0070]

[0071] (4) Calculation of the final included angle Based on the law of cosines, calculate the angle between the satellite (vertices) and the image point and the target point (two sides):

[0072]

[0073] And convert the angle from radians to degrees.

Claims

1. A remote sensing satellite point target real shooting real transmission prediction analysis method, characterized in that, The method includes the following steps: S1. Acquisition of imaging geometric parameters: including imaging start time ts, imaging time tm, and imaging end time te; S2. Imaging Data Volume Calculation: Calculate the amount of data generated by the imaging of point targets; S3. Data transmission duration calculation: Calculate the data transmission duration t_receiving_duration required to complete the imaging data based on the data transmission rate between the satellite and the ground station; S4. Determining the earliest possible data transmission time: The earliest possible data transmission time receivingStartTime = ts + t_threshold, where t_threshold is a time parameter representing the inherent delay; S5. Calculation of data transmission end time: data transmission end time receivingStopTime = receivingStartTime + t_receiving_duration; S6. Data transmission window calculation under staring attitude: Under the condition that the satellite is in staring attitude and the phased array antenna is always pointing to the ground station, calculate the data transmission start time Rs and data transmission end time Re between the satellite and the ground station; S7. Beam scanning angle parameter setting: Set the maximum allowable beam scanning angle A of the phased array antenna; S8. Initial screening of beam scanning angle at imaging time: Calculate the beam scanning angle θ between the phased array antenna normal direction and the ground station direction at imaging time tm. If θ > A, the target at that point cannot transmit data under the imaging attitude and is directly determined not to meet the requirements of real shooting and transmission. If θ ≤ A, proceed to step S9. S9. Starting from the imaging time tm, loop backward according to the preset time step Δt: Calculate the corresponding beam scanning angle θ_now at each time step. When θ_now>A for the first time... Record the previous moment as the latest possible data transmission moment t_max, and end the search; S10. Validity judgment of the latest available data transmission time: If t_max is not found, it is determined that the target at this point does not meet the requirements of real shooting and real transmission; S11. Beam scanning angle and data transmission completion time constraint judgment: If t_max exists, then judge: t_max ≥ receivingStopTime, and proceed to step S12; If the requirements are not met, it means that the imaging data has not been transmitted and the beam scanning angle has exceeded the allowable range, thus failing to meet the requirements for real-time shooting and transmission. S12. Staring attitude data transmission window constraint judgment: Further judgment is made that receivingStopTime ≤ Re. If it is not satisfied, it means that the imaging data has not been transmitted and the satellite has left the data transmission window under the staring attitude. The judgment fails and the requirement of real shooting and transmission is not met. S13. Result determination: Point targets that simultaneously satisfy steps S11 and S12 are determined to be imageable point targets that meet the requirements of real-time shooting and transmission.

2. The method according to claim 1, wherein, In step S1, the acquired imaging geometric parameters also include the satellite's roll angle at the imaging time, the satellite's position coordinates (X, Y, Z) in the WGS84 coordinate system at the imaging time, and the satellite's velocity components (V) at the imaging time. x V y V z ).

3. The method for forecasting and analyzing real-time images and transmissions of remote sensing satellite point targets according to claim 2, characterized in that, The amount of data generated by point target imaging = the amount of imaging data per second by the camera × (te-ts).

4. The method according to claim 3, wherein, The beam scanning angle θ is the angle between the pointing vector of the satellite at a certain roll side angle and the spatial vector pointing from the satellite's current position to the ground station's position.

5. The remote sensing satellite point target real-time image transmission prediction and analysis method according to claim 4, characterized in that, The specific calculation method for the beam scanning angle θ is as follows: S51. Calculation of imaging points under side-swing conditions: Calculate the latitude and longitude of the corresponding ground imaging point based on the satellite's position, velocity, and roll angle. ; S52. Transformation of latitude and longitude to geocentric and Earth-fixed coordinates: Image point With the target point Convert from latitude and longitude to WGS-84 geocentric coordinates: , ; S53. Calculation of spatial distance between three points: Calculate the Euclidean distance between three points. , , ; This indicates the satellite's position in the WGS-84 geocentric-ground-fixed coordinate system; S54. Final Angle Calculation: Based on the cosine theorem, calculate the angle with the satellite as the vertex and the imaging point and the target point as the two sides. That is, the beam scanning angle.

6. The method of claim 5, wherein the method comprises: ， 。 7. An electronic device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the method according to any one of claims 1-6.

8. A computer-readable storage medium for storing computer instructions, characterized in that, When the computer instructions are executed by the processor, they implement the steps of the method according to any one of claims 1-6.

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