A method and system for planning missions on a multi-band push-sweep satellite with reverse push-sweep

Abstract

The present invention provides a multi-band push-sweep satellite mission planning method and system for reverse push-sweep, comprising: firstly, establishing an observation equation for the forward push-sweep by setting an expected attitude pitch angle during the first forward push-sweep, obtaining a zero point for the observation equation using Newton's method, and obtaining the time for the first forward push-sweep to reach the ground point at the geometric center of a mapping area and the expected attitude of the satellite, thereby completing the first push-sweep mission; then, maneuvering the satellite attitude to complete the reverse push-sweep mission; calculating the time for the reverse push-sweep to reach the ground point at the geometric center of the mapping area and the attitude of the satellite by setting the expected attitude pitch angle during the reverse push-sweep; after completing the reverse push-sweep mission, maneuvering the satellite attitude to reach the ground point at the geometric center of the mapping area and the attitude of the satellite; after completing the reverse push-sweep mission, maneuvering the satellite attitude to the expected attitude during the second forward push-sweep, thereby completing the third push-sweep mission, and calculating the start and end times of the three push-sweep missions.

Description

Technical Field

[0001] This invention relates to the field of satellite mission planning technology, and in particular to a multi-band pushbroom on-board mission planning method and system. Background Technology

[0002] In traditional pushbroom imaging, satellites observe along their orbits, but due to camera swath limitations, a single image cannot cover a large area. To increase the swath width of a single satellite image, strip stitching is required.

[0003] However, the traditional multi-strip splicing method usually involves adjusting the satellite's elevation angle to stabilize after completing one strip before conducting the next observation, which affects the satellite's operational efficiency. Summary of the Invention

[0004] This invention provides a multi-band pushbroom on-board mission planning method and system to address the deficiencies in the prior art.

[0005] In a first aspect, the present invention provides a multi-band pushbroom on-board mission planning method, comprising:

[0006] Calculate the time and expected Euler angles at which the satellite first performs a forward push-broom to the geometric center of the surveyed area;

[0007] Calculate the time it takes for the satellite to push back to the geometric center of the ground point in the mapping area, the expected Euler angle, and half the push time;

[0008] Calculate the time and expected Euler angles at which the satellite reaches the geometric center of the mapping area during its second forward pushbroom;

[0009] The desired attitude and desired attitude angular velocity during the satellite push-broom process are calculated using the back-broom mode control algorithm. The current attitude and current attitude angular velocity during the satellite push-broom process are obtained from the attitude determination.

[0010] Calculate the start and end times of the satellite's three push-broom cycles.

[0011] According to the present invention, a multi-band pushbroom on-board mission planning method is provided, which calculates the time and expected Euler angle of the satellite's first forward pushbroom reaching the geometric center ground point of the mapping area, including:

[0012] Obtain the desired pitch angle during the first forward push-broom. Establish the geometric relationship between the satellite and the ground point at the geometric center of the mapping area;

[0013] Establish the observability condition equations for the satellite ;

[0014] Solve using Newton's method The zero point is used to calculate the time it takes for the first forward sweep to reach the geometric center of the surveyed area. ;

[0015] By time Calculate the desired attitude Euler angles during the first forward push. .

[0016] According to the present invention, a multi-band pushbroom on-board mission planning method is provided, which calculates the time for the satellite to pushbroom back to the geometric center ground point of the mapping area, the expected Euler angle, and half the pushbroom time, including:

[0017] Determine the satellite's overhead position during backbroom scanning and establish the observable condition equations for the satellite during backbroom scanning.

[0018] The zero point of the satellite's observability condition equation during backbroom sweeping is solved using Newton's method, thus obtaining the time required for the backbroom sweeping to reach the geometric center of the surveyed area. ;

[0019] Depend on Calculate the desired attitude Euler angles of the backbroom to the geometric center of the ground point in the survey area. ;

[0020] Calculate the half-broom time of the satellite using the observability condition equations of the satellite during backbroom. .

[0021] According to the present invention, a multi-band pushbroom on-board mission planning method is provided, which calculates the time and expected Euler angle of the satellite's second forward pushbroom to the geometric center ground point of the mapping area, including:

[0022] The desired pitch angle for the second forward push-broom is obtained as follows: Establish the geometric relationship between the satellite and the ground point at the geometric center of the mapping area;

[0023] Establish the observability condition equations for the satellite ;

[0024] Solve using Newton's method The zero point is used to calculate the time it takes for the second forward push to reach the geometric center of the surveyed area. ;

[0025] By time Calculate the desired attitude Euler angles during the second forward push-broom. .

[0026] According to the present invention, a multi-band pushbroom on-board mission planning method is provided, which uses a backbroom mode control algorithm to calculate the desired attitude and desired attitude angular velocity of the satellite during the pushbroom process, and obtains the current attitude and current attitude angular velocity of the satellite during the pushbroom process from the attitude determination, including:

[0027] The desired attitude quaternion from the inertial frame to the camera coordinate system without yaw correction is calculated during satellite backbroom. ;

[0028] The desired attitude quaternion from the inertial frame to the satellite's own frame is: ;

[0029] Calculate the desired total attitude angular velocity during satellite backflush. ;

[0030] Find the quaternion of the current attitude of the satellite. and the satellite's current attitude angular velocity .

[0031] According to the present invention, a multi-band pushbroom on-board mission planning method is provided, which calculates the desired attitude quaternion from the inertial frame to the satellite's own frame as follows: ,include:

[0032] The result is obtained from the dynamic link library based on the deflection angle calculation. :

[0033]

[0034] The desired attitude quaternion from the orbital frame to the camera coordinate system is:

[0035]

[0036] The desired attitude quaternion from the inertial frame to the camera coordinate system is: The attitude quaternion from the satellite's own coordinate system to the corresponding camera coordinate system is: Then the desired attitude quaternion of the inertial frame to the satellite body is: .

[0037] According to the present invention, a multi-band pushbroom on-board mission planning method is provided to calculate the desired total angular velocity of the satellite during backbroom. ,include:

[0038] The attitude angle rotation sequence, including yaw angle correction, is determined to be 3213, with the c-axis representing the camera coordinate system and the b-axis representing the satellite body coordinate system.

[0039] Yaw angle of the first rotation around the Zc axis , The second rotation around the Yc axis, pitch angular velocity Perform push sweeping, and These are the desired pitch angles for the current and previous control cycles, the third rotation around the Xc axis, and the roll angle. Perform push sweeping, and These are the desired attitude roll angles for the current and previous control cycles, the yaw angle correction for the fourth rotation around the Zb axis, and the yaw rate. The angular velocity of the satellite relative to the orbital system, projected onto the camera coordinate system, can be obtained from the eccentricity calculation dynamic link library.

[0040]

[0041] M1 represents the rotation matrix around the X-axis, M2 represents the rotation matrix around the Y-axis, and M3 represents the rotation matrix around the Z-axis.

[0042] The projection of the satellite's angular velocity relative to the orbital system onto its body coordinate system is:

[0043]

[0044] The entrainment angular velocity of the orbital system is Projecting onto the satellite's body coordinate system yields:

[0045]

[0046] This represents the proportion of the satellite's ground velocity.

[0047] The desired total angular velocity of the satellite is obtained as follows:

[0048] .

[0049] According to the present invention, a multi-band pushbroom on-board mission planning method is provided, which calculates the start and end times of three pushbroom cycles for a satellite, including:

[0050] Calculate the start time of the first forward push-broom and the end time of the first swab. ;

[0051] Calculate the time to start and stabilize the reverse push-broom. and the end time of reverse push-broom ;

[0052] Calculate the start time of the third push-broom And the end time of the third push-broom ;

[0053] calculate ,like Then The value changed Then the calculation starts again.

[0054] Secondly, the present invention also provides a multi-band pushbroom on-board mission planning system, comprising:

[0055] The first calculation module is used to calculate the time and expected Euler angle when the satellite first performs a forward push-broom to the geometric center ground point of the mapping area;

[0056] The second calculation module is used to calculate the time it takes for the satellite to push back to the ground point at the geometric center of the mapping area, the expected Euler angle, and half the push time;

[0057] The third calculation module is used to calculate the time and expected Euler angles when the satellite reaches the geometric center ground point of the mapping area during its second forward push-broom.

[0058] The fourth calculation module is used to calculate the desired attitude and desired attitude angular velocity during the satellite push-broom process using the back-broom mode control algorithm, and to obtain the current attitude and current attitude angular velocity during the satellite push-broom process from the attitude determination.

[0059] The fifth calculation module is used to calculate the start and end times of the satellite's three push-broom cycles.

[0060] Thirdly, the present invention also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the multi-band pushbroom on-board mission planning method as described above.

[0061] The multi-strip pushbroom on-board mission planning method and system provided by this invention performs imagery of the second strip directly during the retrace process after the first strip is captured. This strategy significantly reduces maneuvering time and improves strip stitching efficiency, thereby achieving effective coverage of multiple strips in a single mission. Compared to the traditional multi-strip forward pushbroom method, the back-broom technique utilizes the flexibility of satellite attitude maneuvering, enabling more efficient multi-strip observation. Attached Figure Description

[0062] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0063] Figure 1 This is a flowchart illustrating the multi-band pushbroom on-board mission planning method provided by the present invention.

[0064] Figure 2 This is a schematic diagram of spatial geometric relationships for three-dimensional mapping provided by the present invention;

[0065] Figure 3 This is a schematic diagram of the total pointing deviation in the first ground push-broom mode provided by the present invention;

[0066] Figure 4 This is a schematic diagram of the satellite X-axis angular velocity deviation in the first Earth-to-ground push-broom mode provided by the present invention;

[0067] Figure 5 This is a schematic diagram of the satellite Y-axis angular velocity deviation in the first Earth-to-ground push-broom mode provided by the present invention;

[0068] Figure 6 This is a schematic diagram of the satellite Z-axis angular velocity deviation in the first Earth-to-ground push-broom mode provided by the present invention;

[0069] Figure 7 This is a schematic diagram of the total pointing deviation in the reverse push-broom mode provided by the present invention;

[0070] Figure 8 This is a schematic diagram of the satellite X-axis angular velocity deviation in the reverse pushbroom mode provided by the present invention;

[0071] Figure 9 This is a schematic diagram of the satellite Y-axis angular velocity deviation in the reverse pushbroom mode provided by the present invention;

[0072] Figure 10 This is a schematic diagram of the satellite Z-axis angular velocity deviation in the reverse pushbroom mode provided by the present invention;

[0073] Figure 11 This is a schematic diagram of the total pointing deviation in the second ground push-broom mode provided by the present invention;

[0074] Figure 12 This is a schematic diagram of the satellite X-axis angular velocity deviation in the second Earth-to-ground push-broom mode provided by the present invention;

[0075] Figure 13 This is a schematic diagram of the satellite Y-axis angular velocity deviation in the second Earth-to-ground push-broom mode provided by the present invention;

[0076] Figure 14 This is a schematic diagram of the satellite Z-axis angular velocity deviation in the second Earth-to-ground push-broom mode provided by the present invention;

[0077] Figure 15 This is a schematic diagram of the structure of the multi-band pushbroom on-board mission planning system provided by the present invention;

[0078] Figure 16This is a schematic diagram of the structure of the electronic device provided by the present invention. Detailed Implementation

[0079] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0080] To address the shortcomings of existing technologies, this invention proposes a multi-strip pushbroom on-board mission planning method that includes reverse pushbroom scanning. By performing the second strip imaging directly during the retrace process after the first strip is captured, the maneuver time is reduced and the strip stitching efficiency is improved, thereby achieving effective coverage of multiple strips in a single mission.

[0081] To achieve the above objectives, the Euler angles involved in the technical solutions provided by this invention are all in 321 transformation order. Figure 1 This is a flowchart illustrating the multi-band pushbroom on-board mission planning method provided in an embodiment of the present invention, as shown below. Figure 1 Shown, including:

[0082] Step 100: Calculate the time and expected Euler angles when the satellite first performs a forward push-broom to the geometric center of the mapping area;

[0083] Step 200: Calculate the time it takes for the satellite to push back to the geometric center of the mapping area, the expected Euler angle, and half the push time;

[0084] Step 300: Calculate the time and expected Euler angles when the satellite reaches the geometric center of the mapping area during its second forward pushbroom.

[0085] Step 400: The desired attitude and desired attitude angular velocity during the satellite push-broom process are calculated using the back-broom mode control algorithm, and the current attitude and current attitude angular velocity during the satellite push-broom process are obtained from the attitude determination.

[0086] Step 500: Calculate the start and end times of the three satellite push-broom cycles.

[0087] In this embodiment of the invention, the observation equation for forward push-broom is first established by setting the desired attitude pitch angle during the first forward push-broom. The zero point of the observation equation is obtained using Newton's method, which yields the time to reach the ground point at the geometric center of the mapping area during the first forward push-broom and the desired attitude of the satellite, thus completing the first push-broom task. Then, the satellite attitude is maneuvered to complete the reverse push-broom task. By setting the desired attitude pitch angle during the reverse push-broom, the time to reach the ground point at the geometric center of the mapping area during the reverse push-broom and the attitude of the satellite are calculated. After completing the reverse push-broom task, the satellite attitude is maneuvered to the desired attitude during the second forward push-broom, and then the third push-broom task can be completed. The start and end times of the three push-broom tasks can be calculated.

[0088] Specifically, it includes the following steps:

[0089] Step 1: Calculate the time it takes for the first forward push to reach the ground point at the geometric center of the survey area and the expected Euler angles of the satellite.

[0090] Step 1.1, as follows Figure 2 The desired pitch angle during the first forward push-broom is: Establish the geometric relationship between the satellite and the ground point at the geometric center of the mapping area;

[0091] Record the ground point at the geometric center of the surveyed area from the satellite push-broom. T At that time, ground point T The geocentric radius is denoted as ,satellite S The geocentric radius is denoted as Speed ​​is denoted as Then the radius vector of the ground point relative to the satellite is

[0092] (1)

[0093] To make the center of the camera lens point towards the ground, then there should be

[0094] (2)

[0095] For satellite orbital angular momentum The unit vector is calculated as follows:

[0096] (3)

[0097] Yaw angle Then the satellite attitude corresponds to The axis direction is

[0098] (4)

[0099] Let the pitch angle be during forward push-broom. The desired pitch angle during the first forward push-broom is: ,but The axis and the geocentric radius of the satellite Angle between the radius and the vector Furthermore, the satellite-target alignment does not pass through the Earth.

[0100] (5)

[0101] Step 1.2: Establish the observability condition equations for the satellite.

[0102] Ignoring the constraint that "the satellite-target line does not pass through the Earth", the observation function constructed based on equation (2) is as follows:

[0103] (6)

[0104] Expanding the Lagrange formula using the triple product of vectors, we have:

[0105]

[0106] Substituting, we get:

[0107] (7)

[0108] Step 1.3: Use Newton's method to find the zero point of the observation equation in Step 1.2, and calculate the time it takes for the first forward sweep to reach the geometric center of the surveyed area. The specific implementation process is as follows:

[0109] Let the observation equation in step 1.2 be... At that time, the target was at a critical position within the satellite's visible range.

[0110] Using Newton's method to find the function The zero point is determined, thus establishing the start and end times when the target becomes visible. Newton's method has... Convergence speed: When the initial value is designed reasonably, the convergence speed is relatively fast. The implementation method is as follows.

[0111] Let the initial value be... In each iteration,

[0112] (8)

[0113] when and The difference is less than a certain small quantity When the solution process converges, The numerical solution to the equation is obtained, and the iteration ends.

[0114] If the number of iterations exceeds a certain upper limit If the initial value still does not converge, then it is considered unreliable. Note The value should not be too large, otherwise there is a possibility of convergence to zero points in other visible segments. Considering the fast convergence characteristics of Newton's iteration method, the embodiment of this invention takes... .

[0115] initial value The selection is as follows, based on the first orbital period (in terms of...). for The latitude of the satellite entering and exiting the quasi-visible phase within the starting point of its orbital period is used to calculate the estimated true anomaly angle at those times. The perigee argument is then used to replace the perigee argument at any given moment within that period, and the true anomaly angle is used... Angle with near point The relationship and the angle of proximity and time The relationship can be used to determine the time of entry and exit from the quasi-visible segment.

[0116] Based on the satellite's geocentric longitude during the ascent and descent phases (different for prograde and retrograde orbits), combined with... , , , And the time of entering and exiting the quasi-visible segment, and These represent the upper and lower bounds of the satellite's geocentric longitude during the ascent phase. and By defining the upper and lower bounds of the satellite's geocentric longitude during the descent phase, the nadir longitude at the moments of entry and exit from the near-visible period is obtained. , , and , and These represent the upper and lower bounds of the longitude of the nadir point at the moment of entering the quasi-visible period. and These represent the upper and lower bounds of the longitude of the nadir point at the moment of exiting the quasi-visible period. Note that after solving, [the following will be applied]. The range of values ​​is limited to .

[0117] Taking longitude From leap to The possibility, for any If (the forward and reverse tracks are different)

[0118] (9)

[0119] Then the corresponding and Substitute a set of feasible initial values ​​into equation (8) to solve.

[0120] Similarly, if (the forward and reverse tracks are different)

[0121] (10)

[0122] Then the corresponding and Substitute a set of feasible initial values ​​into equation (8) to solve.

[0123] Otherwise, the first The orbital period does not have the capability to target The possibility of observation is not involved in the solution process.

[0124] This screening process can also avoid... This is unreasonable.

[0125] Finally, the initial values ​​are substituted into the observation equation. Solution time .

[0126] Step 1.4, based on the time in Step 1.3 Calculate the desired attitude Euler angles during the first forward push. The specific process is as follows:

[0127] Calculate the time it takes for the satellite to push the broom to the ground point at the geometric center of the mapping area. Then, the position of the target in the inertial frame can be determined. ,speed And the satellite's position in the inertial frame. ,speed .

[0128] Yaw angle Then the satellite's desired attitude corresponds to The axis direction is

[0129]

[0130] The desired attitude coordinate system of the satellite is:

[0131] The satellite's current orbital coordinate system is

[0132] The transformation matrix from the inertial frame to the desired satellite attitude coordinate system is:

[0133]

[0134] The transformation matrix from the inertial frame to the satellite's current orbital coordinate system is:

[0135]

[0136] The transformation matrix from the satellite's current orbit coordinate system to its desired attitude coordinate system is:

[0137]

[0138] Define Euler angles in 321 transformation order (Yaw, Pitch, Roll), Attitude matrix is

[0139]

[0140] The required roll angle when the satellite push-broom reaches the geometric center of the mapping area is .

[0141]

[0142] The desired Euler angles of the satellite's attitude during its first forward pushbroom .

[0143] Due to the maximum roll angle during stereoscopic mapping Solutions that do not meet this condition should be discarded.

[0144] Step 2: Calculate the time to push back to the ground point at the geometric center of the survey area, the expected Euler angle of the satellite, and half a push time.

[0145] Step 2.1: During backbroom scanning, the satellite passes overhead. Establish the observable condition equations for the satellite during backbroom scanning. The specific process is as follows:

[0146] According to step 1.1, due to the pitch angle during stable push-broom operation... ,but The axis and the geocentric radius of the satellite Angle between the radius and the vector ,have

[0147] (11)

[0148] The constructed observation function is:

[0149] (12)

[0150] have

[0151] (13)

[0152] right Differentiate:

[0153] (14)

[0154] The visibility function and its derivative can be calculated.

[0155] Step 2.2, similar to step 1.3, uses Newton's method to find the function. The zero point is used to filter the initial values ​​and calculate the time required for the reverse sweep to reach the geometric center of the surveyed area. .

[0156] Step 2.3, based on the time in Step 2.2 The desired attitude Euler angles for the backbroom to the geometric center of the ground point in the surveyed area are calculated as follows: The specific solution process is the same as step 1.4;

[0157] Step 2.4: Calculate the time for half a satellite pushbroom using the observation equations from Step 2.1. The specific process is as follows;

[0158] Longest time for stable reverse push-broom ,in If the time required for the satellite to transition from the first forward pushbroom to the reverse pushbroom is [time], then the start time for the reverse pushbroom stabilization pushbroom is [time]. The start time of the first forward push-broom to reverse push-broom attitude maneuver .

[0159] After the first forward broom transition to the reverse broom attitude maneuver time Then, the initial pitch angle when reverse push-broom begins to stabilize. Euler angles for this orientation are The time required to reach the geometric center of the sweeping area by pushing the broom in this posture is , This can be obtained from the observation equation in step 2.1. At this point, the distance from the ground point where the reverse push sweep begins to stabilize is approximately half the total push sweep length, which is equivalent to a time difference. Then the stable push-broom time Since this estimate has a certain deviation, we can take... .

[0160] Step 3: Calculate the time it takes for the second forward push to reach the ground point at the geometric center of the survey area and the expected Euler angles of the satellite;

[0161] Step 3.1, the desired pitch angle during the second forward push-broom is: The establishment of the geometric relationship between the satellite and the ground point of the geometric center of the mapping area is the same as the first forward push-broom process in step 1.1, and will not be repeated here;

[0162] Step 3.2 establishes the satellite's observability condition equations, which are the same as the observation equations obtained in the first forward pushbroom in Step 1.2, and will not be repeated here;

[0163] Step 3.3: Use Newton's method to find the zero point of the observation equation in Step 3.2, and calculate the time it takes for the second forward sweep to reach the geometric center of the surveyed area. The solution process here is the same as in step 1.3, and will not be repeated here.

[0164] Step 3.4, based on the time in step 3.3 Calculate the desired attitude Euler angles during the second forward push-broom. The solution process here is the same as in step 1.4, and the desired Euler angles of the orientation during the second forward push are obtained. .

[0165] Step 4, the specific process of the reverse push-broom mode control algorithm is as follows;

[0166] Step 4.1, calculate the desired attitude quaternion from the inertial frame to the camera coordinate system without yaw angle correction during satellite backbroom. , as follows:

[0167] This mode involves the entire satellite performing attitude maneuvers at a certain pitch angular velocity within a specific time range, enabling the payload optical axis to perform push-broom motion along the reverse orbit at a constant ground velocity. This is because the camera lens... Shaft installation, therefore according to The control law is designed based on the axis pointing to the ground point, and the spatial geometric relationship is as follows: Figure 3 As shown. Satellite S The geocentric radius is denoted as Speed ​​is denoted as The current sub-satellite point is The Earth's core is .

[0168] The starting point of satellite backbroom is The starting time is The satellite's backflush trajectory is parallel to the forward pushbroom trajectory, and the roll angle is not constant during backflush. Using a 321 rotation sequence, the satellite roll angle is continuously adjusted during elevation pushbroom. After determining the pointing attitude, yaw angle correction is required around the Zb axis.

[0169] According to the task planning procedure, the transition sequence 321 can be obtained. The initial expected attitude Euler angles at time t are , The attitude Euler angles at time t are .

[0170] satellite from From that moment on, at a constant pitch angular velocity Reverse push-broom, then The expected elevation angle of the satellite at any given time is Expected roll angle Obtained by interpolation. Expected Euler angles under 321 transformation order. The corresponding expected attitude quaternion from the orbital system to the camera coordinate system without deflection angle correction is: .

[0171] Step 4.2, calculate the desired attitude quaternion from the inertial frame to the satellite's own frame. , as follows:

[0172] First, the attitude obtained in step 4.1 needs to be corrected for the drift angle. This is done by calculating the drift angle using a dynamic link library. .

[0173]

[0174] The desired attitude quaternion from the orbital frame to the camera coordinate system is

[0175]

[0176] The desired attitude quaternion from the inertial frame to the camera coordinate system is: Since the attitude quaternions from the satellite's intrinsic coordinate system to the corresponding camera coordinate system are... Then the desired attitude quaternion of the inertial frame to the satellite body is: .

[0177] Step 4.3: Calculate the desired total angular velocity of the satellite during backflush. , as follows:

[0178] First, calculate the relative angular velocity with respect to the orbital frame. Since the attitude angle rotation sequence, including yaw correction, is 3213, the yaw angle of the first rotation around the Zc axis... , The second rotation around the Yc axis occurs at a constant pitch angular velocity. Perform push-broom; third rotation around the Xc axis, roll angle Obtained through interpolation It is also obtained through interpolation; the yaw angle is corrected during the fourth rotation around the Zb axis, and the yaw rate is... This can be obtained from the deflection angle calculation dynamic link library. M1 represents the rotation matrix about the X-axis, M2 represents the rotation matrix about the Y-axis, and M3 represents the rotation matrix about the Z-axis.

[0179]

[0180] The satellite's angular velocity relative to its orbital system projected onto its body coordinate system is .

[0181] On the other hand, the entrainment angular velocity of the orbital system is Projecting it onto the satellite's body coordinate system yields

[0182]

[0183] The expected total angular velocity of the satellite is

[0184]

[0185] Step 4.4, obtain the quaternion of the current satellite attitude. and the satellite's current attitude angular velocity ;

[0186] Satellite current attitude quaternion The current attitude angular velocity of the satellite is obtained from the attitude determination. Acquired by attitude determination.

[0187] Step 5: Calculate the start and end times of the three push-broom cycles.

[0188] Step 5.1, calculate the start time of the first forward push-broom. and the end time of the first swab. The start time of the first forward push-broom At the start of imaging The end time of the first push-broom is the start time of the first attitude maneuver. .

[0189] Step 5.2, calculate the time for the reverse push-broom to stabilize. and the end time of reverse push-broom ;

[0190] When reverse push-brooming begins and stabilizes, the ground points to be pushed-broomed are: At that moment, the satellite was in attitude The ground point it points to, and , , Its position relative to the Earth-fixed system can be determined as follows: .

[0191] Reverse push-broom start and stable push-broom timing And the Euler angles of the satellite's orientation pointing to this ground point. The roll angle of the desired attitude Euler angle during the period from the start of stable backbroom pushing to over-the-top is obtained by interpolation. ,and Otherwise, Then start the calculation again from step 5.1.

[0192] When the reverse push-broom ends, the ground points that should be pushed-broomed are: At that moment, the satellite was in attitude The ground point it points to, and , , Its position relative to the Earth-fixed system can be determined as follows: .

[0193] Then calculate the time when the reverse push-broom ends. And the Euler angles of the satellite's orientation pointing to this ground point. and The roll angle of the desired attitude Euler angles during the reverse broom from the overhead period to the end of the broom is obtained by interpolation. ,and Otherwise, Then start the calculation again from step 5.1.

[0194] In summary, the time to stabilize after reverse push-broom is... Reverse push-broom end time .

[0195] Step 5.3, calculate the start time of the third push-broom. And the end time of the third push-broom ;

[0196] Third push-broom start time End time of the third push-broom .

[0197] Step 5.4, Calculation ,if Then the above The value changed Then start the calculation again from step 5.1.

[0198] Based on the above embodiments, in order to verify the effectiveness of the present invention in mission planning on the back-broom satellite of the agile remote sensing optical satellite, the parameters for on-orbit testing of the satellite are as follows:

[0199] 1. Target parameters

[0200] Longitude: -9.13°

[0201] Latitude: 38.79°

[0202] Height: 157.318m

[0203] Reverse push-broom forward pitch angle: 25°

[0204] Solar altitude angle: 63°

[0205] 2. Command parameters

[0206] First push start time: 487510331s

[0207] First push-broom expected Euler angles: Yaw 0°; Pitch 25°; Roll -4.176240753563°

[0208] Duration of the first push: 19.787s

[0209] Second push-broom expected Euler angles: Yaw 0°; Pitch 35°; Roll -6.126368152670°

[0210] Reverse push-broom pitch rate: 1.5° / s

[0211] Reverse stable push-broom start time: 487510367s

[0212] Reverse stable push-broom overpass time: 487510374

[0213] Backward push-broom end time: 487510382s

[0214] Side yaw angle at the start of reverse stable push-broom: -4.88961614°

[0215] Side swing angle during reverse stable push-broom overpass: -4.40630024°

[0216] Side swing angle at the end of reverse stable push-broom: -3.73244541°

[0217] Third push-broom start time: 487510402s

[0218] The expected Euler angles for the third push-broom test are: yaw 0°; pitch -25°; roll -3.737005946494°.

[0219] Duration of the third push-broom: 15.649s

[0220] Based on the above parameters, on-orbit testing of the satellite was conducted, and the backbroom planning and control method was simulated. Analysis was performed on three data strips, where strips 1 and 3 represent ground-to-ground pushbroom, and strip 2 represents backbroom. The results are as follows:

[0221] The expected Euler angles for strip 1 are (0, 25, -4.1762)°, as shown below. Figures 3 to 6 As shown, the total pointing deviation during the ground push sweep was 0.01045° (3σ), the X-axis attitude stability was 0.00081° / s (3σ), the Y-axis attitude stability was 0.00082° / s (3σ), and the Z-axis attitude stability was 0.00070° / s (3σ).

[0222] Strip 2 is a reverse push sweep, such as Figures 7 to 10As shown, the total pointing deviation is 0.12° (3σ), the X-axis attitude stability is 0.0011° / s (3σ), the Y-axis attitude stability is 0.004° / s (3σ), and the Z-axis attitude stability is 0.006° / s (3σ).

[0223] Strip 3 has expected Euler angles of (0, -25, -3.737)°, and the attitude converges after 21 seconds of maneuvering. Figures 11 to 14 As shown in the figure, the total pointing deviation during the ground push sweep was 0.027° (3σ), the X-axis attitude stability was 0.0007° / s (3σ), the Y-axis attitude stability was 0.0006° / s (3σ), and the Z-axis attitude stability was 0.002° / s (3σ).

[0224] The above Figures 3 to 14 The simulation results verify that the proposed method for planning and controlling backbroom imaging using remote sensing satellites can achieve rapid dynamic response and stable adjustment during satellite attitude control, meet imaging accuracy requirements, and ensure the successful completion of on-orbit missions.

[0225] The following describes the multi-band pushbroom on-board mission planning system provided by the present invention. The multi-band pushbroom on-board mission planning system described below can be referred to in correspondence with the multi-band pushbroom on-board mission planning method described above.

[0226] Figure 15 This is a schematic diagram of the structure of the multi-band pushbroom on-board mission planning system provided by the present invention, as shown below. Figure 15 As shown, it includes: a first calculation module 1501, a second calculation module 1502, a third calculation module 1503, a fourth calculation module 1504, and a fifth calculation module 1505, wherein:

[0227] The first calculation module 1501 is used to calculate the time and expected Euler angle of the satellite's first forward push-broom to the ground point at the geometric center of the mapping area; the second calculation module 1502 is used to calculate the time, expected Euler angle, and half push-broom time of the satellite's reverse push-broom to the ground point at the geometric center of the mapping area; the third calculation module 1503 is used to calculate the time and expected Euler angle of the satellite's second forward push-broom to the ground point at the geometric center of the mapping area; the fourth calculation module 1504 is used to calculate the expected attitude and expected attitude angular velocity of the satellite during the push-broom process using the reverse push-broom mode control algorithm, and obtain the current attitude and current attitude angular velocity of the satellite during the push-broom process from the attitude determination; the fifth calculation module 1505 is used to calculate the start and end times of the satellite's three push-brooms.

[0228] Figure 16 An example is a schematic diagram of the physical structure of an electronic device, such as... Figure 16As shown, the electronic device may include: a processor 1610, a communication interface 1620, a memory 1630, and a communication bus 1640. The processor 1610, communication interface 1620, and memory 1630 communicate with each other via the communication bus 1640. The processor 1610 can call logical instructions in the memory 1630 to execute a multi-band pushbroom on-board mission planning method. This method includes: calculating the time and expected Euler angle of the satellite's first forward pushbroom to the geometric center ground point of the mapping area; calculating the time, expected Euler angle, and half a pushbroom time of the satellite's backward pushbroom to the geometric center ground point of the mapping area; calculating the time and expected Euler angle of the satellite's second forward pushbroom to the geometric center ground point of the mapping area; using a backward pushbroom mode control algorithm to calculate the desired attitude and desired attitude angular velocity of the satellite during the pushbroom process, and obtaining the current attitude and current attitude angular velocity of the satellite during the pushbroom process from the attitude determination; and calculating the start and end times of the satellite's three pushbrooms.

[0229] Furthermore, the logical instructions in the aforementioned memory 1630 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0230] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, i.e., they may be located in one location or distributed across multiple network units. Some or all of the modules may be selected based on actual needs to achieve the objectives of the present embodiment. Persons of ordinary skill in the art will be able to understand and implement the present invention without inventive effort.

[0231] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0232] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for planning on-board missions of a multi-band pushbroom satellite with reverse pushbroom capability, characterized in that, include: Determine the time and expected Euler angle when the satellite first performs a forward push sweep to the geometric center of the mapping area; Determine the time it takes for the satellite to push back to the geometric center of the ground point in the mapping area, the expected Euler angle, and half the push time; Determine the time and expected Euler angle at which the satellite reaches the geometric center of the ground point of the mapping area during its second forward pushbroom; The reverse pushbroom mode control algorithm is used to calculate the desired attitude and desired attitude angular velocity during the satellite pushbroom process. The current attitude quaternion and current attitude angular velocity during the satellite pushbroom process are obtained from the attitude determination. Determine the start and end times of the satellite's three push-broom cycles to achieve on-orbit satellite attitude control.

2. The multi-band pushbroom on-board mission planning method according to claim 1, characterized in that, Determine the time and expected Euler angle of the satellite's first forward push sweep to the geometric center of the mapping area, including: Obtain the desired pitch angle during the first forward push-broom. Establish the geometric relationship between the satellite and the ground point at the geometric center of the mapping area; Establish the observability condition equations for the satellite ; Solve using Newton's method The zero point is used to calculate the time it takes for the first forward sweep to reach the geometric center of the surveyed area. ; By time Calculate the desired attitude Euler angles during the first forward push. .

3. The multi-band pushbroom on-board mission planning method according to claim 1, characterized in that, Determine the time it takes for the satellite to backbroom to reach the geometric center of the mapping area, the expected Euler angle, and half the pushbroom time, including: Determine the satellite's overhead position during backbroom scanning and establish the observable condition equations for the satellite during backbroom scanning. The zero point of the satellite's observability condition equation during backbroom sweeping is solved using Newton's method, thus obtaining the time required for the backbroom sweeping to reach the geometric center of the surveyed area. ; Depend on Calculate the desired attitude Euler angles of the backbroom to the geometric center of the ground point in the surveyed area. ; Calculate the half-broom time of the satellite using the observability condition equations of the satellite during backbroom. .

4. The multi-band pushbroom on-board mission planning method according to claim 1, characterized in that, Determine the time and expected Euler angle at which the satellite reaches the geometric center of the mapping area during its second forward pushbroom, including: The desired pitch angle for the second forward push-broom is obtained as follows: Establish the geometric relationship between the satellite and the ground point at the geometric center of the mapping area; Establish the observability condition equations for the satellite ; Solve using Newton's method The zero point is used to calculate the time it takes for the second forward push to reach the geometric center of the surveyed area. ; By time Calculate the desired attitude Euler angles during the second forward push-broom. .

5. The multi-band pushbroom on-board mission planning method according to claim 1, characterized in that, The desired attitude and desired attitude angular velocity during the satellite push-broom process are calculated using a back-broom mode control algorithm. The current attitude and current attitude angular velocity during the satellite push-broom process are obtained from the attitude determination, including: The desired attitude quaternion from the inertial frame to the camera coordinate system without yaw correction is calculated during satellite backbroom. ; The desired attitude quaternion from the inertial frame to the satellite's own frame is: ; Calculate the desired total attitude angular velocity during satellite backflush. ; Find the quaternion of the current attitude of the satellite. and the satellite's current attitude angular velocity .

6. The multi-band pushbroom on-board mission planning method according to claim 5, characterized in that, The desired attitude quaternion from the inertial frame to the satellite's own frame is: ,include: The result is obtained from the dynamic link library based on the deflection angle calculation. : The desired attitude quaternion from the orbital frame to the camera coordinate system is: The desired attitude quaternion from the inertial frame to the camera coordinate system is: The attitude quaternion from the satellite's own coordinate system to the corresponding camera coordinate system is: Then the desired attitude quaternion of the inertial frame to the satellite body is: .

7. The multi-band pushbroom on-board mission planning method according to claim 5, characterized in that, Calculate the desired total attitude angular velocity during satellite backflush. ,include: The attitude angle rotation sequence, including yaw angle correction, is determined to be 3213, with the c-axis representing the camera coordinate system and the b-axis representing the satellite body coordinate system. Yaw angle of the first rotation around the Zc axis , The second rotation around the Yc axis, pitch angular velocity Perform push sweeping, and These are the desired pitch angles for the current and previous control cycles, the third rotation around the Xc axis, and the roll angle. Perform push sweeping, and These are the desired attitude roll angles for the current and previous control cycles, the yaw angle correction for the fourth rotation around the Zb axis, and the yaw rate. The angular velocity of the satellite relative to the orbital system, projected onto the camera coordinate system, can be obtained from the eccentricity calculation dynamic link library. M1 represents the rotation matrix around the X-axis, M2 represents the rotation matrix around the Y-axis, and M3 represents the rotation matrix around the Z-axis. The projection of the satellite's angular velocity relative to the orbital system onto its body coordinate system is: The entrainment angular velocity of the orbital system is Projecting onto the satellite's body coordinate system yields: This represents the proportion of the satellite's ground velocity. The desired total angular velocity of the satellite is obtained as follows: 。 8. The multi-band pushbroom on-board mission planning method according to claim 1, characterized in that, Determine the start and end times of the three satellite push-broom cycles, including: Calculate the start time of the first forward push-broom and the end time of the first swab. ; Calculate the time to start and stabilize the reverse push-broom. and the end time of reverse push-broom ; Calculate the start time of the third push-broom And the end time of the third push-broom ; calculate ,like Then The value changed Then the calculation starts again.

9. A multi-band pushbroom on-board mission planning system based on the multi-band pushbroom on-board mission planning method according to any one of claims 1 to 8, characterized in that, include: The first processing module is used to determine the time and expected Euler angle when the satellite first performs a forward push-broom to the geometric center ground point of the mapping area; The second processing module is used to determine the time it takes for the satellite to push back to the geometric center of the ground point of the mapping area, the expected Euler angle, and half the push time; The third processing module is used to determine the time and expected Euler angle when the satellite reaches the geometric center ground point of the mapping area during the second forward push-broom; The fourth processing module is used to calculate the desired attitude and desired attitude angular velocity during the satellite push-broom process using the back-broom mode control algorithm, and to obtain the current attitude and current attitude angular velocity during the satellite push-broom process from the attitude determination. The fifth processing module is used to determine the start and end times of the satellite's three push-broom cycles in order to achieve on-orbit satellite attitude control.

10. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the multi-band pushbroom on-board mission planning method as described in any one of claims 1 to 8.

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