A method for reducing the field cut height error of a spaceborne rim-mounted payload

Abstract

The application discloses a method for reducing the field cutting error of a spaceborne edge load, which comprises the following steps: acquiring the driving current of an edge load motor through telemetry instructions; when the driving current of the edge load motor exceeds a threshold, calculating the pointing accuracy error of the edge load motor through the driving current of the edge load motor, and then compensating the actual pointing accuracy of the edge load in-orbit measurement; and the application is based on the ground vacuum 1:1 life test, a mathematical model between the driving current when the motor rotates and the to-position angle is established to estimate and compensate the actual pointing accuracy of the edge load in-orbit measurement in the life cycle of the spaceborne edge load.

Description

Technical Field

[0001] This invention relates to the field of atmospheric vertical profile detection technology at the edge of the Earth, and in particular to a method for reducing the field-of-view height cut-off error of spaceborne edge payloads. Background Technology

[0002] The spaceborne limb payload is based on CCD detector imaging and observes the distribution of trace gas concentrations in the vertical direction of the atmosphere by tangenting the altitude. The spaceborne limb detector is carried on a sun-synchronous orbit atmospheric sounding satellite to obtain limb atmospheric radiation from the Earth's tangent altitude direction. It can be used to monitor the spatiotemporal distribution and changes of column concentrations of trace pollutant gas components (O3, NO2, HCHO and SO2, etc.) in the stratosphere from 10km to 40km.

[0003] The spaceborne edge payload measurement unit consists of an edge payload motor, a front telescope, and a spectrometer. The edge payload motor comprises a drive section and a measurement section. The drive section includes a brushless DC motor and a servo drive circuit, while the measurement section includes a specially coated reflector and a resolver position sensor. The edge payload motor control employs a current-based three-loop PID algorithm (position, velocity, and current three-loop). Input rotation commands generate PWM waves, which are then fed into a three-phase MOSFET drive bridge for high-precision rotation. The front telescope splits the optical signal reflected by the edge payload motor's reflector through a grating and sends it to a spectrometer at different wavelengths for signal measurement.

[0004] like Figure 1 The diagram illustrates the operation of the edge payload. The payload is mounted on the back of the satellite in its flight path, operating at an orbital altitude of 705 km. The observation field of view is approximately 3081 km from the payload. Its basic operation is as follows: after the satellite reaches the observation position, the edge payload motor rotates to its initial position, and the spectrometer collects the optical signal of the current field of view. Then, the edge payload motor rotates 60″, and due to the principle of specular reflection, the observation angle rotates outward 120″ along the Earth's tangent, increasing the observation altitude by 1.8 km. The spectrometer then collects the optical signal of the current field of view again. The edge payload motor rotates approximately 22 times in this sequence, increasing the observation altitude by a total of 40 km, covering the entire stratosphere. Typically, the deviation of the single step angle of the edge payload motor in the design is approximately ±10″, and this error will affect the accuracy of the retrieved vertical gas profile.

[0005] Based on the analysis of the SCIAMACHY payload launched by the European Space Agency, the sources of altitude cut-off error mainly consist of the following: (1) mismatch of the payload observation field of view; (2) offset of the scanning optical components; (3) changes in platform attitude, such as pitch, yaw, roll, etc.; (4) errors of the motors and control of the edge payloads; (5) errors generated by the solar tracking control. (1) and (2) are fixed errors, which can be corrected by precise coordinate measurement before launch and used as constants; (3) can be compensated and corrected by satellite attitude information; (5) can be analyzed and corrected by atmospheric information of latitude and longitude in different seasons and combined with other on-orbit payload data.

[0006] (4) This refers to the pointing accuracy error of the edge load motor, which is mainly affected by the control circuit algorithm, bearing structure, lubrication method and working mode. The fundamental reason why the edge load motor is affected by this is that the bearing of the edge load motor adopts a molybdenum disulfide solid lubricating film, and the working mode of the edge load motor is the corner mode. During long-term operation, the wear of the bearing and the shedding of the lubricating film at relevant positions cause changes in friction torque.

[0007] The design on-orbit life of the edge load is 8 years, and the effective operating revolutions of the edge load motor are no less than 1.8 million revolutions. Due to the characteristic of the molybdenum disulfide solid lubricant film on the bearings to detach due to friction, and the fact that the edge load motor operates in an angular mode—accelerating, moving at a constant speed, and then decelerating to the target position—the lubricant film is easily maintained and plays a role in reducing friction when the friction force is low. As the friction force increases, the lubricant film wears and detaches, and the friction is in a boundary lubrication or mixed lubrication state. When the friction force further increases and causes the boundary lubricant film to rupture and fail, the friction will be in a dry cutting state without lubrication. During each rail operation, the motor is typically observed at multiple designated positions. A single rotation process is divided into acceleration, constant speed, and deceleration stages. This means that the bearing of the edge load motor is repeatedly impacted at the observed positions, making the molybdenum disulfide solid lubricant film at these bearing locations more prone to wear and detachment. The detached lubricant film forms pits, leading to lubrication failure and increased friction. Meanwhile, the detached molybdenum disulfide solid lubricant powder will be distributed in various parts of the bearing as the motor rotates. There is a possibility that the lubricant film will be refilled at the detached points or accumulate in a certain part of the bearing, resulting in uneven distribution of bearing friction and irregular changes in friction over time.

[0008] Generally, a shorter motor arrival time is better (the shorter the time, the more accurate the height segmentation). In the early stage of the lifespan, the motor arrival time under edge load should not exceed 60ms, while in the middle and late stages of the lifespan, the arrival time mostly exceeds 200ms. In the edge observation process, if the time point for each image is set to start 60ms later, the actual observation position of the first few images of the CCD observation will be deviated. The shorter the detector exposure time, the more images will be affected.

[0009] like Figure 2 The curves showing the motor response time and positioning accuracy under small-angle edge loads at the beginning, middle, and end of the motor's lifespan are illustrated. In the early stages of the lifespan, the motor reaches and stabilizes at the target position within 60ms after starting rotation. However, in the middle and late stages, damage to the molybdenum disulfide solid lubricant film increases bearing friction, introducing overshoot into the motor control system. The motor needs to adjust the overshoot after reaching the target position, resulting in a damped oscillation-like motion curve. The edge load needs to be photographed 60ms after rotation begins. Taking the shortest exposure time of 0.2s and the longest exposure time of 3.2s as examples, in the early stages of the lifespan, even with an exposure time of 0.2s, the field of view of the edge load is not affected by the motor's pointing accuracy. However, in the middle and late stages, if the first image exposure time is 0.2s, the motor may not have reached the target position within the entire exposure time, potentially affecting the second image. If the first image exposure time is 3.2s, there will be an error in the pointing of the edge load's field of view within the first 0.5s of exposure. Summary of the Invention

[0010] The purpose of this invention is to provide a method for reducing the field-of-view height cutting error of spaceborne edge loads by correcting the actual vertical resolution error caused by the edge load motor through positioning accuracy error.

[0011] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0012] A method for reducing the field-of-view height cut error of a spaceborne territorial load involves obtaining the drive current of the territorial load motor through telemetry commands. When the drive current of the territorial load motor exceeds a threshold, the pointing accuracy error of the territorial load motor is calculated based on the drive current of the territorial load motor, thereby compensating for the actual pointing accuracy of the on-orbit measurement of the territorial load.

[0013] This invention aims to analyze the sources of pointing accuracy errors in edge-load motors after long-term on-orbit operation, and based on 1:1 vacuum life test data from the ground, to find the relationship between changes in frictional torque and motor pointing accuracy, thereby correcting the cutting-off accuracy of edge-load motors. The correction or compensation method involves correcting the actual pointing position of the edge-load motor.

[0014] P T =AP e

[0015] Among them, P T A represents the actual pointing position of the motor under edge load, A represents the target position to which the command needs to be rotated, and P represents the actual pointing position of the motor under edge load. e This refers to the pointing accuracy error of the motor under edge load.

[0016] Regarding the pointing accuracy error P of the motor under edge load e Based on ground-based 1:1 vacuum life test data, the fitting relationship between the data and the drive current I of the motor under edge load was obtained. The ground-based 1:1 vacuum life test platform was set up as follows: the test platform includes...

[0017] Simulated space environment: Vacuum tank, used to house the edge load motor, simulating the space environment in which the edge load motor operates; Vacuum tank computer, used to complete the vacuum control of the vacuum tank, drive the vacuum pump to evacuate the vacuum tank, and at the same time collect the temperature of the motor casing.

[0018] Simulated edge load motor: The edge load motor is housed and fixed inside the vacuum tank by a mounting flange, with a pendulum mirror installed below it; the pendulum mirror records the real-time rotation angle of the edge load motor.

[0019] Data acquisition device: motor drive box, which is connected to the motor containing the edge load via cable for driving and power supply, and is used to read the actual rotation angle, arrival time and drive current of the motor; motor control and data acquisition computer, which sends instructions to the motor drive box to control the rotation of the motor containing the edge load, and receives, saves and displays the data read by the motor drive box;

[0020] The method for obtaining the fitting relationship between the pointing accuracy error Pe of the motor under edge load and the drive current I of the motor under edge load based on the above-mentioned test platform includes the following steps:

[0021] Step S100: Simulate the working environment of the motor under edge load and build a test platform based on the accelerated life test working mode;

[0022] Step S200: Based on the on-orbit working time and working mode of the edge load motor, accelerate the completion of the entire on-orbit working cycle of the edge load motor on the test platform; collect and record the drive current, real-time angle, target position for each rotation, and system time during the entire rotation process of the edge load motor on the track; specifically, this includes, in conjunction with the test platform:

[0023] Step A100: The motor control and data acquisition computer sends a motor initialization rotation command to the motor drive box, so that the motor is in the observation zero position;

[0024] Step A200: Based on the on-rail working mode of the edge load motor, the motor control and data acquisition computer sends instructions to the motor drive box to accelerate the completion of the on-rail working state of the edge load motor throughout the entire working cycle.

[0025] Step A300: During the motor rotation process, the motor drive box sends the real-time angle value of the adjacent load motor and the current value of the motor coil to the motor control and data acquisition computer in real time, and adds the system timestamp when storing the data.

[0026] Step S300: Calculate the pointing accuracy error by the difference between the angle of the target position and the real-time angle for each rotation, select a suitable data source, and establish a fitting relationship between the drive current and the pointing accuracy error; the selection of a suitable data source is based on the drive current value within the time of the data source covering the current change value throughout the entire life cycle, which can represent the bearing friction condition throughout the entire life cycle.

[0027] Compared with existing technologies, the beneficial effects of this invention are as follows: Based on a 1:1 life test in a ground vacuum, this invention establishes a mathematical model between the driving current and the positioning angle when the motor rotates, in order to estimate and compensate for the actual pointing accuracy of the on-orbit measurement of the edge during the life cycle of the spaceborne edge load. Attached Figure Description

[0028] Figure 1 This is a schematic diagram illustrating the working mode of edge loads;

[0029] Figure 2 This is a schematic diagram showing the response time and positioning accuracy curves of a motor under small-angle edge load during the early, middle, and late stages of its lifespan.

[0030] Figure 3 This is a schematic diagram of the working mode of the motor under edge load.

[0031] Figure 4 This is a schematic diagram of the single-cycle current curves of a motor under edge load during the initial, middle, and final stages of its lifespan.

[0032] Figure 5 This is a schematic diagram showing the relationship between the frictional torque and drive current of a motor under edge load.

[0033] Figure 6 This is a schematic diagram of a 1:1 ground-based accelerated life test platform;

[0034] Figure 7 This is a schematic diagram of the single-step current curve for the motor life test under edge load within the experimental platform.

[0035] Figure 8 A schematic diagram of the drive current curve of the motor during one rotation cycle for a load at the edge.

[0036] Figure 9 A schematic diagram showing the change of motor rotation angle over time under different drive current values;

[0037] Figure 10 Enlarged view of the curves for different drive current values;

[0038] Figure 11 This is a schematic diagram showing the change in motor pointing accuracy error as a function of drive current. Detailed Implementation

[0039] The present invention will be further described in detail below with reference to the embodiments shown in the accompanying drawings, but this does not constitute any limitation on the present invention.

[0040] This invention aims to address the issue of high pointing accuracy in the later stages of the territorial load motor's lifespan, which further affects the accuracy of territorial load product data inversion. However, this problem cannot be avoided simply by deleting the first image, as the territorial load is located in a sun-synchronous orbit. Its flight speed and the load's viewing angle determine its spatial resolution. Excessive observation time at the same altitude inevitably leads to a decrease in spatial resolution. Taking O3 and SO2 measurements as examples, O3's vertical concentration peaks at 30 km in the stratosphere, exhibiting significant spectral absorption characteristics. Typically, a single image with a short integration time is sufficient for the O3 data inversion algorithm. In contrast, SO2 has a uneven global distribution and is associated with sudden natural disasters such as volcanic eruptions and anthropogenic emissions, resulting in weaker spectral absorption. Therefore, the territorial load needs to acquire multiple images over the measured area to meet the data inversion requirements. The territorial load observation process primarily targets the distribution of high-concentration target gases at the stratosphere. Therefore, in most cases, a single image is sufficient to complete the measurement. Furthermore, since the load's flight speed multiplied by the imaging time equals the spatial resolution of the flight direction, fewer images result in higher spatial resolution. In other words, the first image reflects the highest resolution observed at the edge;

[0041] To address the issue that height cut errors cannot be avoided through deletion, this invention provides a method for reducing height cut errors in the field of view of spaceborne edge loads, as detailed in the appendix. Figure 3 , 4 5, 6, 7, 8, 9, 10, 11, specifically including:

[0042] (I) Operating mode of motor under edge load

[0043] See attached document Figure 3 This is the operating mode of the edge-load motor, which operates in a sun-synchronous orbit at an altitude of 705 km. Each orbital operation lasts approximately 50 minutes, and the motor completes 1.8 × 10⁻⁶ rotations within 8 years. 6To accelerate the completion of the entire on-orbit operation cycle of the edge load motor on the ground, which operates intermittently, each rotation cycle (one revolution) requires 22 small-angle movements and one zero-return movement. Each small-angle scan is 60″, completed within 60ms, followed by a 140ms wait before the next small-angle movement, taking 0.2s each time. After completing 22 small-angle movements, the large-angle zero-return movement is initiated, completed within 4.2s. Therefore, a 1:1 vacuum life test platform can be designed on the ground to change the on-orbit operation mode of the edge load motor from intermittent to continuous, thus completing the 1:1 ground accelerated life test in 179 days.

[0044] (II) Single-cycle current curve of motor under edge load

[0045] See attached document Figure 4 The figures show the single-cycle current curves at the beginning, middle, and end of the measured lifespan of the motor under edge load. Phase ab represents the single-step rotation phase of the motor. Specifically, the motor starts from the observation zero position (first step), rotates 60" angles in a single step, pauses for 200ms, and then begins the next rotation, for a total of 22 steps. After the single-step rotation is completed, phase bc represents the load return to zero reset phase, where the motor directly rotates from the last observed position back to the observation zero position. The current value in phase ab is relatively small and stable because the rotation angle of the motor under edge load is small each time, resulting in a small drive current. The current in phase bc exhibits an M-shaped pattern, with the first and last peaks representing the acceleration and deceleration phases of the motor under edge load, respectively, and the smooth current in the middle representing the constant speed phase. Comparing figures (a) and (b), the overall current in the middle and end of the lifespan is greater than the current in the beginning of the lifespan, and the current fluctuations are larger in the middle and end of the lifespan.

[0046] (III) Motor friction torque and drive current curves under edge load

[0047] Furthermore, the shaft resistance torque of the motor under edge load was measured before and after the life test. The shaft resistance torque before the life test was 21 mN·m, and after the life test, it was 55 mN·m, an increase of 34 mN·m. This verifies that the molybdenum disulfide solid lubricating film is continuously worn away during the life test, causing an increase in bearing friction torque, and that there is a direct correlation between the motor drive current and the friction torque. (See attached...) Figure 5 The graph shows the relationship between motor friction torque and drive current. The relationship between motor drive current and friction torque can be obtained by measuring the motor drive current corresponding to different torques under the condition of increasing axial load on the motor. The data results show that the motor friction torque and drive current are linearly related and are directly proportional to the torque variation range during the life test.

[0048] The change in frictional torque caused variations in the rotation time and accuracy of the edge load motor. Due to increased friction at these locations, the motor control system experienced overshoot, increasing the actual arrival time from approximately 40ms initially (frictional torque of 21mN·m) to over 200ms (frictional torque of 55mN·m). The actual pointing accuracy reached an error of 10" to 20" after 60ms of rotation, with variations at each position. After adjusting for the overshoot, the pointing accuracy stabilized within the design specification of 10"; therefore, the time affected by the overshoot was over 260ms from the start of each rotation, and this time was further extended by the increase in frictional torque. According to the edge load motor scanning time requirements, the motor needs to complete rotation within 60ms for the load to begin imaging. The design value of 60ms cannot be extended; therefore, this overshoot will affect the first few images of the edge load, resulting in an actual resolution deviation of approximately 0.6km.

[0049] Based on the linear correlation between motor friction torque and drive current, and their proportionality within the torque variation range during the life test, the change in friction torque can be characterized using the motor drive current, which can be obtained using telemetry commands. Therefore, a 1:1 ground-based accelerated life test platform can be designed, as shown in the attached figure. Figure 6 It includes

[0050] Simulated space environment: Vacuum tank, used to house the edge load motor, simulating the space environment in which the edge load motor operates; Vacuum tank computer, used to complete the vacuum control of the vacuum tank, drive the vacuum pump to evacuate the vacuum tank, and at the same time collect the temperature of the motor casing.

[0051] Simulated edge load motor: The edge load motor is housed and fixed inside the vacuum tank by a mounting flange, with a pendulum mirror installed below it; the pendulum mirror records the real-time rotation angle of the edge load motor.

[0052] Data acquisition device: motor drive box, which is connected to the motor containing the edge load via cable for driving and power supply, and is used to read the actual rotation angle, arrival time and drive current of the motor; motor control and data acquisition computer, which sends instructions to the motor drive box to control the rotation of the motor containing the edge load, and receives, saves and displays the data read by the motor drive box;

[0053] The method for obtaining the fitting relationship between the pointing accuracy error Pe of the motor under edge load and the drive current I of the motor under edge load based on the experimental platform includes the following steps:

[0054] Step S100: Simulate the working environment of the motor under edge load and build a test platform based on the accelerated life test working mode;

[0055] Step S200: Based on the on-rail working time and working mode of the edge load motor, accelerate the completion of the working status of the edge load motor in the entire on-rail working cycle on the test platform; collect and record the drive current, real-time angle, target position of each rotation and system time during the rotation process of the edge load motor in the entire on-rail working cycle.

[0056] Step S300: Calculate the pointing accuracy error by the difference between the angle of the target position and the real-time angle for each rotation, select a suitable data source, and establish a fitting relationship between the drive current and the pointing accuracy error.

[0057] For information on suitable data sources, please refer to the appendix. Figure 7 The single-step current curve of the edge load motor life test in the experimental platform is used to average the small-angle rotation current of the edge load motor on a daily basis to reflect the change of the edge load motor drive current throughout the entire life cycle. It can be seen that the current change is uniform from February 13, 2022 to February 19, 2022, and the current value during this period encompasses the current change value of the entire life cycle, which can represent the bearing friction condition throughout the entire life cycle. Data from February 13, 2022 to February 19, 2022 is selected to analyze the relevant parameters of the motor.

[0058] For the selection of the observation position of the motor under edge load and the calculation of the drive current, please refer to the appendix. Figure 8 The edge-load motor has 23 observation positions in the observation mode design. The motor performance parameters at each position differ throughout its lifespan, but the analysis method remains consistent. The edge-load motor's observation zero position (first step) is chosen for data analysis because the motor experiences significant acceleration after a large-angle return to zero, resulting in relatively severe damage to the solid lubricating film. The performance parameters at this position show a more pronounced difference between the early, middle, and late stages of the lifespan. The drive current is continuously acquired in real-time at a frequency of 1kHz. The current data at the edge-load motor's observation zero position (first step) is extracted and averaged to represent the current at that position during that revolution. The average current at all positions within that time period is calculated hourly to represent the drive current at that position during that time period.

[0059] Then, a fitting relationship between the drive current and the pointing accuracy error is established, referring to the appendix. Figure 9 , 10The curves showing the change of motor rotation angle over time under different drive current values ​​reveal that when the current is low, the edge load motor fluctuates within the allowable error range after rotating to the target position. As the current gradually increases, the edge load motor needs to adjust the overshoot after initially reaching the target position; the motor's direction first deviates from the target rotation position before readjusting back to it. The offset between the motor's direction and the target rotation position increases with the increase of the motor drive current. When the motor drive current exceeds a certain threshold, the motor's direction offset also exceeds the allowable range of rotation accuracy error for the edge load motor. In this case, when the motor stabilizes within the target rotation range again, the actual time it takes for the motor to reach its target position far exceeds the time it takes for the edge load to begin imaging. In the edge load working mode, the shorter the imaging time of the first few frames, the more images are affected by the actual time it takes for the motor to reach its target position.

[0060] This shows that different currents result in different deviations in the motor's pointing accuracy. A curve is plotted with current I on the x-axis and pointing accuracy error Pe on the y-axis, as shown in the attached figure. Figure 11 As shown, by fitting the discrete points, the pointing accuracy error P of the motor under edge load is obtained. e The fitting relationship between the drive current I of the motor with the edge load is:

[0061] Pe = a × b I +c

[0062] Where 'a' and 'b' are the exponential distribution fitting parameters, and 'c' is the pointing accuracy error offset. The purpose of this offset is to ensure that the pointing accuracy error value is greater than or equal to 0. This is because after the motor with the adjacent load stabilizes at the target rotation position, it will fluctuate around the target value, resulting in a negative pointing accuracy error. The example in the figure uses 18 discrete points to fit the curve. Theoretically, the more discrete points selected, the better the fitted curve matches the relationship between the actual current and the pointing accuracy deviation. Simultaneously, by inputting the current value, the deviation of the current motor's pointing accuracy can be obtained.

[0063] Furthermore, the driving current I of the edge load motor is used as a telemetry variable to compensate for the pointing position of the edge load during on-orbit operation. This current, along with the imaging data, is transmitted to the ground station. (See attached figure.) Figure 3 The actual pointing positions of the 22 small-angle movements were corrected to complete the actual cutting height splicing. Figure 11 The threshold value for the motor drive current I of the edge load motor used in this invention is 8.05mA. When the motor drive current I exceeds the threshold value,

[0064] P r =AP e

[0065] Among them, P T A represents the actual pointing position of the motor under edge load, A represents the target position to which the command needs to be rotated, and P represents the actual pointing position of the motor under edge load.e The pointing accuracy error of the edge load motor is used to compensate for the vertical resolution of edge load observation. Therefore, after the edge load is in orbit, the driving current I of the edge load motor is obtained by telemetry data transmission. The pointing accuracy error value of the edge load motor is estimated based on the parameter relationship established by the 1:1 life test on the ground.

[0066] The above-described embodiments are preferred embodiments of the present invention and are only used to facilitate the illustration of the present invention. They are not intended to limit the present invention in any way. Any person skilled in the art who makes local modifications or alterations to the technical content disclosed in the present invention without departing from the scope of the technical features of the present invention shall still fall within the scope of the technical features of the present invention.

Claims

1. A method for reducing the field-of-view height cut error of spaceborne territorial loads, characterized in that: The drive current of the edge load motor is obtained through telemetry commands. When the drive current of the edge load motor exceeds the threshold, the pointing accuracy error of the edge load motor is calculated through the drive current of the edge load motor, and then the actual pointing accuracy of the edge load motor measured on the track is compensated. The pointing accuracy error of the motor under the edge load The fitting relationship between the drive current I of the motor with the edge load is: , where a and b are the exponential distribution fitting parameters, and c is the pointing accuracy error offset; The method for compensating for the actual pointing accuracy of the on-rail measurement near the edge is to correct the actual pointing position of the motor of the near-edge load: in, A represents the actual pointing position of the motor under edge load, while A is the target position to which the motor needs to rotate, as set by the command. This refers to the pointing accuracy error of the motor under edge load.

2. The method for reducing the field-of-view height cut error of spaceborne territorial loads according to claim 1, characterized in that: Obtain the pointing accuracy error of the motor under edge load and the drive current of the motor with edge load I The method for fitting the relationship between them includes the following steps: Step S100: Simulate the working environment of the motor under edge load and build a test platform based on the accelerated life test working mode; Step S200: Based on the on-rail working time and working mode of the edge load motor, accelerate the completion of the working status of the edge load motor in the entire on-rail working cycle on the test platform; collect and record the drive current, real-time angle, target position of each rotation and system time during the rotation process of the edge load motor in the entire on-rail working cycle. Step S300: Calculate the pointing accuracy error by the difference between the angle of the target position and the real-time angle for each rotation, select a suitable data source, and establish a fitting relationship between the drive current and the pointing accuracy error.

3. The method for reducing the field-of-view height cut error of spaceborne territorial loads according to claim 2, characterized in that: The test platform in step S100 includes Vacuum container, used to house edge load motors, simulating the space environment in which edge load motors operate; The vacuum tank computer is used to complete the vacuum control of the vacuum tank, drive the vacuum pump to evacuate the vacuum tank, and at the same time collect the temperature of the motor housing of the adjacent load. The edge load motor is fixed inside the vacuum tank by a mounting flange, and a pendulum mirror is installed below it; the pendulum mirror records the real-time angle of rotation of the edge load motor. The motor drive box connects to the adjacent load motor via cables for driving and power supply, and is used to read the actual rotation angle, arrival time and drive current of the motor. The motor control and data acquisition computer sends commands to the motor drive box to control the rotation of the adjacent load motor, and receives, saves and displays the data read by the motor drive box.

4. The method for reducing the field-of-view height cut error of spaceborne territorial loads according to claim 3, characterized in that: Step S200 specifically includes: Step A100: The motor control and data acquisition computer sends an initial rotation command for the edge load motor to the motor drive box, so that the edge load motor is in the observation zero position. Step A200: Based on the on-rail working mode of the edge load motor, the motor control and data acquisition computer sends instructions to the motor drive box to accelerate the completion of the on-rail working state of the edge load motor throughout the entire working cycle. In step A300, during the rotation of the edge load motor, the motor drive box sends the real-time angle value of the edge load motor and the current value of the coil to the motor control and data acquisition computer in real time, and adds a system timestamp when storing the data.

5. The method for reducing the field-of-view height cut error of spaceborne territorial loads according to claim 2, characterized in that: The selection criterion for the appropriate data source is that the drive current value within the time of the data source encompasses the current change value throughout the entire life cycle, which can represent the bearing friction condition throughout the entire life cycle.

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