A method and system for on-board stereo mapping mission planning

Abstract

This invention provides a method and system for on-board stereo mapping mission planning. First, during stereo mapping, the geometric relationship between the ground points at the center of the mapping area set of satellites is constructed. Then, an observability function is established based on a perturbation model. Subsequently, initial values ​​are screened and selected based on different prograde and retrograde orbits. By substituting the initial values ​​that meet the conditions into the observability function, the position and velocity of the target and the satellite in the inertial frame are obtained after calculating the time it takes for the satellite to push-broom to the geometric center ground point of the mapping area. The desired attitude Euler of the satellite during push-broom is calculated, and the start and end times of two push-brooms are obtained based on the single push-broom time. Finally, a stereo mapping control algorithm is provided to calculate the desired attitude, current attitude, desired attitude angular velocity, and current attitude angular velocity of the satellite during the stereo mapping mission, thus completing the on-board stereo mapping mission planning.

Description

Technical Field

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

[0002] With the continuous advancement of my country's aerospace technology, satellite mission planning methods have gradually shifted to direct mission planning by in-orbit imaging satellites. One planning method for implementing in-orbit missions involves analyzing the geometric relationships between the satellite, the ground, and the target to derive the conditional equations for target observability, and then solving these equations to determine the feasible time window for target observation. This method has a relatively complex model, requiring the construction of a reasonable model solution method. How to acquire high-precision three-dimensional measurement data using limited computing resources is crucial for the practical implementation of this type of method. Among existing surveying and mapping technologies, stereo mapping is an emerging technology that utilizes stereo images for surveying and three-dimensional modeling. In recent years, several stereo mapping satellites have been in orbit. These satellites can acquire high-resolution stereo images of ground targets, and their onboard high-resolution cameras can achieve high-precision photogrammetry without ground control points. Furthermore, they are equipped with multiple medium-precision star sensors, which can meet the requirements of high reliability, long-term operation, and high-precision three-axis pointing determination for surveying and mapping missions.

[0003] Based on a survey of existing patent achievements, there is already an agile mission planning method for Earth-based satellites, but there is currently no on-board mission planning method based on stereo mapping. Summary of the Invention

[0004] This invention provides a method and system for planning on-board stereo mapping missions, in order to overcome the deficiencies in the existing technology.

[0005] In a first aspect, the present invention provides a method for planning on-board stereo mapping missions, comprising:

[0006] Based on the spatial geometric relationship between the satellite, ground target points, and the Earth, establish the satellite observation condition equation;

[0007] The initial values ​​of the satellite observation condition equations are filtered to obtain the filtered initial values;

[0008] Based on the initial values ​​after filtering, calculate the time it takes for the satellite to reach the ground point at the geometric center of the mapping area during two push-broom cycles, and the corresponding expected attitude Euler angles;

[0009] The total time for one push-broom operation and the start and end times of the two push-broom operations are calculated by taking the time for the satellite to reach the ground point at the geometric center of the mapping area during the two push-broom operations and the corresponding expected attitude Euler angles.

[0010] By utilizing multiple push-broom times of the satellite, the desired attitude, current attitude, desired attitude angular velocity, and current attitude angular velocity of the satellite during active push-brooming are calculated.

[0011] According to the method for planning on-board stereo mapping missions provided by the present invention, a satellite observation condition equation is established based on the spatial geometric relationship between the satellite, ground target points, and the Earth, including:

[0012] Establish the geometric relationship between the satellite and the ground point at the geometric center of the mapping area;

[0013] The satellite observation condition equation is established based on the aforementioned geometric relationship. The time required for the satellite to push the ground to the geometric center of the surveyed area is calculated.

[0014] According to a stereo mapping on-board mission planning method provided by the present invention, the initial values ​​of the satellite observation condition equation are screened to obtain the screened initial values, including:

[0015] The critical conditions for the visibility window are estimated based on the latitude and longitude of the satellite's nadir point, thus obtaining the quasi-visible segment;

[0016] The initial values ​​after filtering are obtained by filtering the initial values ​​according to the different forward and reverse trajectories.

[0017] According to the method for planning a stereo mapping on-board mission provided by the present invention, the initial values ​​are obtained by filtering initial values ​​based on different prograde and retrograde orbits, including:

[0018] by for The latitude of the satellite entering and exiting the quasi-visible phase during the first orbital period at the start of the current orbital period is used to calculate the estimated true anomaly angle at the time of entry and exit from the quasi-visible phase. The perigee argument is then used to replace the perigee argument at any moment within that period, and the true anomaly angle is used... Angle with near point The relationship and the angle of proximity and time Based on the relationship, determine the time of entry and exit from the quasi-visible segment;

[0019] Based on the satellite's geocentric longitude during the ascent and descent phases, 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 entering and exiting the near-visible period can be 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 sub-satellite point at the moment of exiting the quasi-visible period.

[0020] According to the present invention, a method for on-board stereo mapping mission planning includes calculating the time taken for the satellite to reach the geometric center ground point of the mapping area during two push-broom operations, and the corresponding expected attitude Euler angles, based on the initial values ​​after filtering.

[0021] Substituting the filtered initial values ​​into the satellite observation condition equation Solve using Newton's method The zero point is used to obtain the time when the first sweep reaches the geometric center of the surveyed area. ;

[0022] according to Calculate the desired attitude Euler angles during the first push-broom. ;

[0023] Substituting the filtered initial values ​​into the satellite observation condition equation Solve using Newton's method The zero point is used to obtain the time when the second sweep reaches the geometric center of the surveyed area. ;

[0024] according to Calculate the desired attitude Euler angles during the second push-broom. .

[0025] According to the on-board mission planning method for stereo mapping provided by the present invention, the total time of one satellite push-broom and the start and end times of the two satellite push-brooms are calculated based on the time taken for the satellite to reach the geometric center ground point of the mapping area during two push-broom cycles and the corresponding desired attitude Euler angles, including:

[0026] Calculate the total time for one push-broom cycle ;

[0027] Calculate the start time of the first push-broom and the end time of the first swab. ;

[0028] Calculate the start time of the second push-broom and the end time of the second push-broom .

[0029] According to the present invention, a method for on-board stereo mapping mission planning utilizes multiple push-broom times of the satellite to calculate the desired attitude, current attitude, desired attitude angular velocity, and current attitude angular velocity of the satellite during active push-broom operations, including:

[0030] The current working camera is determined by ground remote control commands. When the high-resolution linear array is working, the coordinate system is from the local system to the second camera coordinate system of the high-resolution camera. When working with hyperspectral imaging, the coordinate system is from the hyperspectral camera coordinate system. When working with infrared, the coordinate system is from the infrared camera coordinate system. The coordinate system of the satellite body is obtained and transferred to the coordinate system of the second camera. posture quaternions ;

[0031] The desired attitude Euler angles under the 321 transformation sequence are determined as follows: The desired attitude quaternion from the uncorrected yaw angle orbital system to the camera coordinate system is obtained as follows: ;

[0032] Use deflection angle For the desired attitude quaternion is Make corrections:

[0033]

[0034] The desired attitude quaternion from the orbital system to the camera coordinate system after adding the yaw angle correction is:

[0035]

[0036] The desired attitude quaternion from the inertial frame to the camera coordinate system is obtained as follows: The attitude quaternion from the satellite's own coordinate system to the camera's coordinate system is: The desired attitude quaternion of the inertial frame to the satellite body is obtained as follows: ;

[0037] Satellite current attitude quaternion Acquired by attitude determination;

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

[0039] Yaw angle of the first rotation around the Zc axis yaw rate The second rotation around the Yc axis, pitch angle pitch angular velocity The third rotation around the Xc axis, roll angle The process involves pushing and sweeping, followed by a fourth rotation around the Zb axis to correct the flow angle. The projection of the satellite's angular velocity relative to the orbital system onto the camera coordinate system is:

[0040]

[0041] The satellite's angular velocity relative to its orbital system projected onto its body coordinate system is ;

[0042] The entrainment angular velocity of the orbital system is Projecting onto the satellite's body coordinate system yields:

[0043]

[0044] The desired total angular velocity of the satellite is obtained as follows:

[0045]

[0046] satellite angular velocity Acquired by attitude determination.

[0047] Secondly, the present invention also provides a stereo mapping on-board mission planning system, comprising:

[0048] The first calculation module is used to establish the satellite observation condition equations based on the spatial geometric relationship between the satellite, ground target points and the Earth.

[0049] The second calculation module is used to filter the initial values ​​of the satellite observation condition equation to obtain the filtered initial values;

[0050] The third calculation module is used to calculate the time it takes for the satellite to reach the ground point at the geometric center of the mapping area during two push-broom cycles, and the corresponding expected attitude Euler angles, based on the initial values ​​after filtering.

[0051] The fourth calculation module is used to calculate the total time of one push-broom operation of the satellite, as well as the start and end times of the two push-broom operations, based on the time taken by the satellite to reach the ground point at the geometric center of the mapping area during two push-broom operations and the corresponding expected attitude Euler angles.

[0052] The fifth calculation module is used to calculate the desired attitude, current attitude, desired attitude angular velocity, and current attitude angular velocity of the satellite during active push-brooming by utilizing multiple push-brooming times of the satellite.

[0053] 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 stereo mapping on-board mission planning method as described above.

[0054] Fourthly, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the stereo mapping on-board mission planning method as described above.

[0055] The stereo mapping on-board mission planning method and system provided by this invention establishes and solves the satellite observability condition equations based on stereo mapping technology, accurately calculating the start and end times of satellite push-broom operations and the desired satellite attitude. Compared to previous mission planning methods, this invention has the advantage of achieving convergence in a shorter time and fewer iterations using limited on-board resources, thus completing the predetermined mission. Attached Figure Description

[0056] 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.

[0057] Figure 1 This is a flowchart illustrating the on-board mission planning method for stereo mapping provided by the present invention;

[0058] Figure 2 This is a schematic diagram of the geometric relationship between the satellite and the ground point at the geometric center of the surveying area, provided by this invention.

[0059] Figure 3 This is a schematic diagram of the total pointing deviation during the push-broom phase of an on-orbit satellite test strip provided by the present invention;

[0060] Figure 4 This is a schematic diagram of the elevation angle deviation of the satellite orbit system during the push-broom phase of an on-orbit satellite test strip provided by the present invention;

[0061] Figure 5 This is a schematic diagram of the roll angle deviation of the satellite orbit system during the push-broom phase of an on-orbit satellite test strip provided by the present invention;

[0062] Figure 6 This is a schematic diagram of the yaw angle deviation of the satellite orbital system during the push-broom phase of an on-orbit satellite test strip provided by the present invention;

[0063] Figure 7 This is a schematic diagram of the total pointing deviation during the second push-broom period of the on-orbit satellite test strip provided by the present invention;

[0064] Figure 8 This is a schematic diagram of the elevation angle deviation of the satellite orbit system during the second push-broom test strip of the on-orbit satellite provided by the present invention;

[0065] Figure 9 This is a schematic diagram of the roll angle deviation of the satellite orbit system during the second push-broom test strip of the on-orbit satellite provided by the present invention;

[0066] Figure 10 This is a schematic diagram of the yaw angle deviation of the satellite orbital system during the second push-broom test strip of the on-orbit satellite provided by the present invention;

[0067] Figure 11 This is a schematic diagram of the structure of the stereo mapping on-board mission planning system provided by the present invention;

[0068] Figure 12 This is a schematic diagram of the structure of the electronic device provided by the present invention. Detailed Implementation

[0069] 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.

[0070] To address the problems existing in the prior art, this invention proposes a method for on-board planning of stereo mapping missions. It should be noted that the on-board mission planning problem typically refers to, under various constraints, specifying which ground target a satellite will observe at which time period and with what attitude, while optimizing an objective function that includes information such as the number of images and the observation area.

[0071] Figure 1 This is a flowchart illustrating the on-board mission planning method for stereo mapping provided in an embodiment of the present invention, as shown below. Figure 1 As shown, it includes:

[0072] Step 100: Establish the satellite observation condition equations based on the spatial geometric relationships between the satellite, ground target points, and the Earth;

[0073] Step 200: Filter the initial values ​​of the satellite observation condition equation to obtain the filtered initial values;

[0074] Step 300: Calculate the time it takes for the satellite to reach the ground point at the geometric center of the mapping area during the two push-broom cycles, and the corresponding expected attitude Euler angles, based on the initial values ​​after filtering.

[0075] Step 400: Calculate the total time of one push-broom operation and the start and end times of the two push-broom operations of the satellite based on the time taken for the satellite to reach the geometric center ground point of the mapping area during the two push-broom operations and the corresponding desired attitude Euler angles.

[0076] Step 500: Using multiple push-broom times of the satellite, calculate the desired attitude, current attitude, desired attitude angular velocity, and current attitude angular velocity of the satellite during the active push-broom process.

[0077] The embodiments of this invention first establish the geometric relationship between the ground points at the center of the satellite's mutual mapping area set during stereo mapping, and then, based on... Perturbation model establishes observability function Subsequently, initial values ​​are screened and selected based on the different forward and reverse trajectories. This step mainly involves selecting values ​​that meet the requirements of the target. Using initial values ​​with observability potential in the solution process can avoid some inconsistencies. By substituting the initial values ​​that meet the conditions into the observability function, after obtaining the time it takes for the satellite to push-broom to the ground point at the geometric center of the mapping area, the position and velocity of the target and the satellite in the inertial frame can be obtained. The desired attitude Euler of the satellite during the push-broom is also calculated. Finally, based on the time of a single push-broom, the start and end times of two push-brooms can be obtained. This invention utilizes Newton's method to find the observability function. By obtaining the zero point, the start and end times of the target's visibility can be determined. When the initial value is designed reasonably, this method has an extremely fast convergence speed.

[0078] Specifically, the steps include the following:

[0079] Step 1: Establish the satellite observation condition equations, which include the following steps:

[0080] Step 1.1: Establish the geometric relationship between the satellite and the ground point at the geometric center of the mapping area;

[0081] like Figure 2 As shown, the ground point at the geometric center of the surveyed area is recorded when the satellite pushes through it. 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

[0082] (1)

[0083] To make the center of the camera lens point towards the ground, then there should be

[0084] (2)

[0085] For satellite orbital angular momentum The unit vector is calculated as follows:

[0086] (3)

[0087] Yaw angle Then the satellite attitude corresponds to The axis direction is

[0088] (4)

[0089] Because the angle of stereo mapping is The desired pitch angle during the first push-broom is ,but The axis and the geocentric radius of the satellite Angle between the radius and the vector And since the satellite-target line does not pass through the Earth, we have:

[0090] (5)

[0091] The desired pitch angle during the second push-broom is ,but The axis and the geocentric radius of the satellite Angle between the radius and the vector .

[0092] Step 1.2: Construct the observability function F(t) based on the relevant geometric relationships;

[0093] When the satellite pushes the ground point to the geometric center of the mapping area hour, and The included angle is denoted as , and the direction vector of the star and the ground The included angle is denoted as From geometric relationships, we can know

[0094] (6)

[0095] Adjust the above equation Differentiation yields,

[0096]

[0097] At the angle Within the range of variation, It is an increasing function.

[0098] From the dihedral angle formula, we can obtain that... ,have

[0099]

[0100] again ,have

[0101]

[0102] During stereoscopic mapping, the maximum roll angle .

[0103] When the Earth is considered a perfect sphere, then when and hour, Take the maximum value ,

[0104]

[0105] Ignoring the constraint that "the satellite-target line does not pass through the Earth", the observation function constructed based on equation (5) is as follows:

[0106] (7)

[0107] Expanding the Lagrange formula using the triple product of vectors, we have:

[0108] (8)

[0109] right Differentiate:

[0110] (9)

[0111] Equation (7) can be used to calculate the visibility function and its derivative.

[0112] when (10)

[0113] At that time, the target was at a critical position within the satellite's visible range.

[0114] Step 2, initial value selection and filtering, can be divided into the following two steps;

[0115] Step 2.1: Estimate the critical conditions of the visibility window by considering only the latitude and longitude of the satellite nadir point, thereby obtaining the "quasi-visible segment";

[0116] Using equation (11) to determine the true anterior angle Convert to near point angle Note that the quadrant and period information of the true near point angle should be preserved.

[0117] (11)

[0118] Using the near-point angle shown in equation (12) and time The relationship can be used to determine the time of entry and exit from the quasi-visible segment.

[0119] (12)

[0120] For the initial time,

[0121] (13)

[0122] Step 2.2: Based on the different forward and reverse trajectories, initial values ​​are selected to have the possibility of observing the target T and are used in the solution.

[0123] 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.

[0124] 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 Note that after solving, The range of values ​​is limited to , 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 sub-satellite point at the moment of exiting the quasi-visible period.

[0125] Taking longitude From leap to The possibility, for any If (the forward and reverse tracks are different)

[0126] (14)

[0127] Then the corresponding and As a set of feasible initial values, substitute them into equation (10) to solve.

[0128] Similarly, if (the forward and reverse tracks are different)

[0129] (15)

[0130] Then the corresponding and As a set of feasible initial values, substitute them into equation (10) to solve.

[0131] Otherwise, the first The orbital period does not have the capability to target The possibility of observation is not involved in the solution process.

[0132] This screening process can also avoid... This is not in line with the understanding.

[0133] Step 3: Calculate the Euler angles of the desired attitude during the first push-broom. The time between the first sweep and the geometric center of the surveyed area. And the desired Euler angles during the second push-broom The time between the second sweep and the ground point at the geometric center of the surveyed area ;

[0134] Based on the above calculation formula, we first calculate the time between the geometric center of the ground point in the two satellite push-broom mapping areas, and then calculate the desired attitude Euler during the push-broom according to the formula, as follows:

[0135] Step 3.1: Substitute the initial values ​​selected in Step 2.2 into the observability function in Step 1.2 to calculate the time it takes for the first sweep to reach the geometric center of the surveyed area. The calculation method can be to solve for the zero point of the observation equation using Newton's method. The solution to the equation is the time it takes to push the broom to the ground point at the geometric center of the survey area.

[0136] Step 3.2, the time from the first sweep to the ground point at the geometric center of the surveyed area, calculated in Step 3.1. Based on the calculated Euler angles of the expected attitude during the first push-broom The desired attitude is calculated as follows:

[0137] Calculate the time it takes for the satellite to push the broom to reach the geometric center of the ground point in 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 .

[0138] Yaw angle Then the satellite's desired attitude corresponds to The axis direction is

[0139]

[0140] The desired attitude coordinate system of the satellite is:

[0141] The satellite's current orbital coordinate system is

[0142] The transformation matrix from the inertial frame to the desired satellite attitude coordinate system is:

[0143]

[0144] The transformation matrix from the inertial frame to the satellite's current orbital coordinate system is:

[0145]

[0146] The transformation matrix from the satellite's current orbit coordinate system to its desired attitude coordinate system is:

[0147]

[0148] Define Euler angles in 321 transformation order (Yaw, Pitch, Roll), the attitude matrix is:

[0149]

[0150] The required roll angle when the satellite push-broom reaches the geometric center of the mapping area is .

[0151]

[0152] Then, the desired Euler angles of the satellite's attitude during the first push-broom. (321 turn to sequence), the desired Euler angles of the second push-broom operation (321 turn sequence).

[0153] Due to the maximum roll angle during stereoscopic mapping Solutions that do not meet this condition should be discarded.

[0154] Step 3.3: Substitute the initial values ​​selected in Step 2.2 into the observation function in Step 1.2 to calculate the time it takes for the second sweep to reach the geometric center of the surveyed area. ;

[0155] Step 3.4, the time from the second sweep to the ground point at the geometric center of the surveyed area, calculated in Step 3.3. Based on the calculation of the expected Euler angles of the second push-broom The expected attitude is calculated in the same way as in step 3.2;

[0156] Step 4: Calculate the total time for one push-broom cycle. And the start and end times of the two sweeps.

[0157] Step 4.1 by The total time for a single push-broom cycle is calculated.

[0158] The start and end times of the two push-broom cycles can then be calculated, and the specific steps are as follows:

[0159] 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.

[0160] Let the initial value be... In each iteration,

[0161] (16)

[0162] when and The difference is less than a certain small quantity When the solution process converges, The iteration ends when the numerical solution of the equation is obtained.

[0163] Step 4.2, calculate the start time of the first push-broom. and the end time of the first swab. ;

[0164] Step 4.3, calculate the start time of the second push-broom. and the end time of the second push-broom .

[0165] Note that 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, this report takes... .

[0166] Step 5: Calculate the desired attitude, current attitude, desired attitude angular velocity, and current attitude angular velocity during the push-broom process; the specific steps are as follows:

[0167] Step 5.1, Determining the desired pose

[0168] The currently operating camera is determined by ground-based remote control commands. When the high-resolution linear array is operating, the coordinate system is from the local system to the second camera coordinate system of the high-resolution camera. When working with hyperspectral imaging, the coordinate system is from the hyperspectral camera coordinate system. When working with infrared, the coordinate system is from the infrared camera coordinate system. (Without adding yaw angle). The attitude quaternions from the satellite's own coordinate system to the corresponding camera coordinate system can be obtained. .

[0169] Based on the onboard planning procedures or ground remote control commands, the expected Euler angles under the 321 rotation sequence can be obtained as follows: The corresponding expected attitude quaternion from the orbital system to the camera coordinate system without deflection angle correction is: This attitude requires flow angle correction. The flow angle is calculated using a dynamic link library. .

[0170]

[0171] The desired attitude quaternion from the orbital system to the camera coordinate system after adding the yaw angle correction is:

[0172]

[0173] 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: .

[0174] Step 5.2, Current pose determination

[0175] Satellite current attitude quaternion Acquired by attitude determination.

[0176] Step 5.3, Determining the desired attitude angular velocity

[0177] Next, the satellite The desired angular velocity at time t is calculated.

[0178] First, the relative angular velocity with respect to the orbital frame is calculated. Since the attitude angle rotation sequence, including yaw correction, is 3213, the angular velocities of the first three rotations are all 0. The fourth rotation around the Zb axis performs yaw correction, and the yaw rate is... This can be obtained from the yaw angle calculation dynamic link library. Then, the satellite's angular velocity relative to the orbital system projected onto the camera coordinate system is...

[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 5.4, Calculate the current attitude angular velocity

[0186] satellite angular velocity Acquired by attitude determination.

[0187] Based on the above embodiments, in order to verify the effectiveness of the present invention in satellite-based stereo mapping mission planning, the satellite was tested in orbit, and the high-resolution camera stereo mapping mission mode for celestial calibration was analyzed.

[0188] The test parameters for this task mode are as follows:

[0189] 1. Target parameters

[0190] Objective 1:

[0191] Sao_Paulo

[0192] Longitude -46.6°

[0193] Latitude -23.56°

[0194] Height 767.921m

[0195] Stereoscopic surveying angle: 45°

[0196] 2. Command parameters

[0197] High-resolution camera stereo mapping task with sky calibration (ground planning):

[0198] Surveying angle 45°

[0199] Strip 1 parameters:

[0200] Imaging begins at 487517039s

[0201] Yaw angle 0°

[0202] Pitch angle 22.5°

[0203] Roll angle -6.737703145388°

[0204] Push-broom duration: 30.750433s

[0205] Strip 2 parameters:

[0206] Imaging begins at 487517102s.

[0207] Yaw angle 0°

[0208] Pitch angle -22.5°

[0209] Roll angle -4.144166010715°

[0210] Push-broom duration: 30.750433s

[0211] Based on the above parameters, on-orbit testing of the satellite was conducted, and the on-board mission planning method for stereo mapping was simulated. The test results are as follows:

[0212] The desired Euler angles for strip 1 are (0, 22.5, -6.7377)°, with a total pointing deviation of 0.01120° (3σ) during the ground push-broom period. The X-axis attitude stability is 0.00067° / s (3σ), the Y-axis attitude stability is 0.00091° / s (3σ), and the Z-axis attitude stability is 0.00071° / s (3σ). For example... Figures 3-6 As shown.

[0213] The desired Euler angles for strip 2 are (0, -22.5, -4.1441)°. Attitude convergence occurs after 28 seconds of maneuvering. The total pointing deviation during the ground push-sweep is 0.01513° (3σ). The X-axis attitude stability is 0.00062° / s (3σ), the Y-axis attitude stability is 0.00105° / s (3σ), and the Z-axis attitude stability is 0.00087° / s (3σ). Figures 7-10 As shown.

[0214] The above Figures 3-10 The simulation results validated the proposed on-board stereo mapping mission planning method. When the high-resolution camera completes the stereo mapping task, it can quickly converge the satellite attitude error to a low level, thus meeting the imaging accuracy requirements and ensuring the successful completion of the satellite's on-orbit mission.

[0215] The stereo mapping on-board mission planning system provided by the present invention is described below. The stereo mapping on-board mission planning system described below and the stereo mapping on-board mission planning method described above can be referred to in correspondence.

[0216] Figure 11 This is a schematic diagram of the structure of the on-board mission planning system for stereo mapping provided in an embodiment of the present invention, as shown below. Figure 11 As shown, it includes: a first calculation module 1101, a second calculation module 1102, a third calculation module 1103, a fourth calculation module 1104, and a fifth calculation module 1105, wherein:

[0217] The first calculation module 1101 is used to establish satellite observation condition equations based on the spatial geometric relationship between the satellite, the ground target point, and the Earth; the second calculation module 1102 is used to filter the initial values ​​of the satellite observation condition equations to obtain filtered initial values; the third calculation module 1103 is used to calculate the time for the satellite to reach the ground point at the geometric center of the mapping area during two push-broom operations, and the corresponding expected attitude Euler angles, based on the filtered initial values; the fourth calculation module 1104 is used to calculate the total push-broom time of the satellite and the start and end times of the two push-broom operations, based on the time for the satellite to reach the ground point at the geometric center of the mapping area during two push-broom operations and the corresponding expected attitude Euler angles; the fifth calculation module 1105 is used to calculate the expected attitude, current attitude, expected attitude angular velocity, and current attitude angular velocity of the satellite during active push-broom operations using multiple push-broom times of the satellite.

[0218] Figure 12 An example is a schematic diagram of the physical structure of an electronic device, such as... Figure 12 As shown, the electronic device may include: a processor 1210, a communications interface 1220, a memory 1230, and a communications bus 1240, wherein the processor 1210, the communications interface 1220, and the memory 1230 communicate with each other through the communications bus 1240. The processor 1210 can call logic instructions in the memory 1230 to execute a stereo mapping on-board mission planning method. This method includes: establishing satellite observation condition equations based on the spatial geometric relationship between the satellite, ground target points, and the Earth; filtering the initial values ​​of the satellite observation condition equations to obtain filtered initial values; calculating the time taken for the satellite to reach the geometric center ground point of the mapping area during two push-broom operations, and the corresponding desired attitude Euler angles, based on the filtered initial values; calculating the total push-broom time of the satellite and the start and end times of the two push-broom operations using the time taken for the satellite to reach the geometric center ground point of the mapping area during two push-broom operations and the corresponding desired attitude Euler angles; and calculating the desired attitude, current attitude, desired attitude angular velocity, and current attitude angular velocity of the satellite during active push-broom operations using multiple push-broom times of the satellite.

[0219] Furthermore, the logical instructions in the aforementioned memory 1230 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, essentially, 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.

[0220] In another aspect, the present invention also provides a non-transitory computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the stereo mapping on-board mission planning method provided by the above methods. This method includes: establishing a satellite observation condition equation based on the spatial geometric relationship between the satellite, ground target points, and the Earth; filtering the initial values ​​of the satellite observation condition equation to obtain filtered initial values; calculating the time taken for the satellite to reach the ground point at the geometric center of the mapping area during two push-broom operations, and the corresponding desired attitude Euler angles, based on the filtered initial values; calculating the total push-broom time of the satellite and the start and end times of the two push-broom operations using the time taken for the satellite to reach the ground point at the geometric center of the mapping area during two push-broom operations and the corresponding desired attitude Euler angles; and calculating the desired attitude, current attitude, desired attitude angular velocity, and current attitude angular velocity of the satellite during active push-broom operations using multiple push-broom times of the satellite.

[0221] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0222] 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.

[0223] 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 stereo mapping missions, characterized in that, include: Based on the spatial geometric relationship between the satellite, ground target points, and the Earth, establish the satellite observation condition equation; The initial values ​​of the satellite observation condition equations are filtered to obtain the filtered initial values; Based on the initial values ​​after filtering, calculate the time it takes for the satellite to reach the ground point at the geometric center of the mapping area during two push-broom cycles, and the corresponding expected attitude Euler angles; The total time for one push-broom operation and the start and end times of the two push-broom operations are calculated by taking the time for the satellite to reach the ground point at the geometric center of the mapping area during the two push-broom operations and the corresponding expected attitude Euler angles. By utilizing multiple push-broom times of the satellite, the desired attitude, current attitude, desired attitude angular velocity, and current attitude angular velocity of the satellite during active push-brooming are calculated.

2. The method for planning on-board stereo mapping missions according to claim 1, characterized in that, Based on the spatial geometric relationships between the satellite, ground target points, and the Earth, satellite observation condition equations are established, including: Establish the geometric relationship between the satellite and the ground point at the geometric center of the mapping area; The satellite observation condition equation is established based on the aforementioned geometric relationship. The time required for the satellite to push the ground to the geometric center of the surveyed area is calculated.

3. The method for planning on-board stereo mapping missions according to claim 1, characterized in that, The initial values ​​of the satellite observation condition equations are filtered to obtain the filtered initial values, including: The critical conditions for the visibility window are estimated based on the latitude and longitude of the satellite's nadir point, thus obtaining the quasi-visible segment; The initial values ​​after filtering are obtained by filtering the initial values ​​according to the different forward and reverse trajectories.

4. The method for planning on-board stereo mapping missions according to claim 3, characterized in that, Based on the different initial values ​​selected for forward and reverse trajectories, the initial values ​​after selection are obtained, including: by for The latitude of the satellite entering and exiting the quasi-visible phase during the first orbital period at the start of the current orbital period is used to calculate the estimated true anomaly angle at the time of entry and exit from the quasi-visible phase. The perigee argument is then used to replace the perigee argument at any moment within that period, and the true anomaly angle is used... Angle with near point The relationship and the angle of proximity and time Based on the relationship, determine the time of entry and exit from the quasi-visible segment; Based on the satellite's geocentric longitude during the ascent and descent phases, 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 entering and exiting the near-visible period can be 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 sub-satellite point at the moment of exiting the quasi-visible period.

5. The method for planning on-board stereo mapping missions according to claim 1, characterized in that, Based on the initial values ​​after filtering, the time it takes for the satellite to reach the ground point at the geometric center of the mapping area during two push-broom cycles, and the corresponding expected attitude Euler angles, are calculated, including: Substituting the filtered initial values ​​into the satellite observation condition equation Solve using Newton's method The zero point is used to obtain the time when the first sweep reaches the geometric center of the surveyed area. ; according to Calculate the desired attitude Euler angles during the first push-broom. ; Substituting the filtered initial values ​​into the satellite observation condition equation Solve using Newton's method The zero point is used to obtain the time when the second sweep reaches the geometric center of the surveyed area. ; according to Calculate the desired attitude Euler angles during the second push-broom. .

6. The method for planning on-board stereo mapping missions according to claim 1, characterized in that, The total time for one satellite push-broom operation and the start and end times of the two satellite push-broom operations are calculated based on the time taken for the satellite to reach the geometric center ground point of the mapping area during its two push-broom operations, and the corresponding desired attitude Euler angles. This includes: Calculate the total time for one push-broom cycle ; Calculate the start time of the first push-broom and the end time of the first swab. ; Calculate the start time of the second push-broom and the end time of the second push-broom .

7. The method for planning on-board stereo mapping missions according to claim 1, characterized in that, By utilizing multiple push-broom times of the satellite, the desired attitude, current attitude, desired attitude angular velocity, and current attitude angular velocity of the satellite during active push-brooming are calculated, including: The current working camera is determined by ground remote control commands. When the high-resolution linear array is working, the coordinate system is from the local system to the second camera coordinate system of the high-resolution camera. When working with hyperspectral imaging, the coordinate system is from the hyperspectral camera coordinate system. When working with infrared, the coordinate system is from the infrared camera coordinate system. The coordinate system of the satellite body is obtained and transferred to the coordinate system of the second camera. posture quaternions ; The desired attitude Euler angles under the 321 transformation sequence are determined as follows: The desired attitude quaternion from the uncorrected yaw angle orbital system to the camera coordinate system is obtained as follows: ; Use deflection angle For the desired attitude quaternion is Make corrections: The desired attitude quaternion from the orbital system to the camera coordinate system after adding the yaw angle correction is: The desired attitude quaternion from the inertial frame to the camera coordinate system is obtained as follows: The attitude quaternion from the satellite's own coordinate system to the camera's coordinate system is: The desired attitude quaternion of the inertial frame to the satellite body is obtained as follows: ; Satellite current attitude quaternion Acquired by attitude determination; The rotation sequence of attitude angles, including yaw angle correction, is determined to be 3213, with the c-axis representing the orbital coordinate system and the b-axis representing the satellite body coordinate system. Yaw angle of the first rotation around the Zc axis yaw rate The second rotation around the Yc axis, pitch angle pitch angular velocity The third rotation around the Xc axis, roll angle The process involves pushing and sweeping, followed by a fourth rotation around the Zb axis to correct the flow angle. The projection of the satellite's angular velocity relative to the orbital system onto the camera coordinate system is: The satellite's angular velocity relative to its orbital system projected onto its body coordinate system is ; The entrainment angular velocity of the orbital system is Projecting onto the satellite's body coordinate system yields: The desired total angular velocity of the satellite is obtained as follows: satellite angular velocity Acquired by attitude determination.

8. A stereo mapping on-board mission planning system, characterized in that, include: The first calculation module is used to establish the satellite observation condition equations based on the spatial geometric relationship between the satellite, ground target points and the Earth. The second calculation module is used to filter the initial values ​​of the satellite observation condition equation to obtain the filtered initial values; The third calculation module is used to calculate the time it takes for the satellite to reach the ground point at the geometric center of the mapping area during two push-broom cycles, and the corresponding expected attitude Euler angles, based on the initial values ​​after filtering. The fourth calculation module is used to calculate the total time of one push-broom operation of the satellite, as well as the start and end times of the two push-broom operations, based on the time taken by the satellite to reach the ground point at the geometric center of the mapping area during two push-broom operations and the corresponding expected attitude Euler angles. The fifth calculation module is used to calculate the desired attitude, current attitude, desired attitude angular velocity, and current attitude angular velocity of the satellite during active push-brooming by utilizing multiple push-brooming times of the satellite.

9. 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 stereo mapping on-board mission planning method as described in any one of claims 1 to 7.

10. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the stereo mapping on-board mission planning method as described in any one of claims 1 to 7.

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