Ground evaluation device and method for scanning effect of long-time airborne platform

Abstract

The embodiment of the invention provides a ground evaluation device and method for the scanning effect of a long-time airborne platform, and the device comprises a data processor, a servo control processor, a three-axis test rotary table, and a photoelectric load. The photoelectric load is installed on the three-axis test rotary table, the servo control processor is electrically connected with the three-axis test rotary table and the photoelectric load, and the servo control processor is electrically connected with the data processor; the servo control processor is used for collecting entity data and transmitting the entity data to the servo control processor; the data processor is used for evaluating the scanning effect of the long-time air platform through the entity data, the design data and the virtual test scene data; the photoelectric load is used for receiving a working instruction sent by the servo control processor to control the scanning work of the photoelectric load; the three-axis test rotary table is used for simulating the attitude change of the long-time air-staying platform in the air. According to the scheme, through the ground evaluation device, the scanning effect of the long-time air platform is evaluated on the ground, the universality is good, and engineering practice is easy.

Description

Technical Field

[0001] The present invention relates to the field of ground imaging technology, and in particular to a ground evaluation device and method for the scanning effect of a long-term airborne platform. Background Art

[0002] Compared with space-based and air-based Earth observation systems, Earth observation systems working in near-space have a wide coverage range, relatively high resolution, and can be deployed in specific areas according to needs to achieve all-weather and all-day Earth observation. They have been widely used in land and resources observation, ocean monitoring, disaster prevention and mitigation, and emergency response.

[0003] In the near-space environment, the general altitude is above 20km. Usually, the stratospheric airship needs to tow the optoelectronic payload to the specified altitude to carry out the ground scanning mission and evaluate the ground scanning effect. If the design needs to be adjusted, the optoelectronic payload needs to be recovered and debugged, and then released again with the stratospheric airship after modification. Conducting this experiment requires a lot of time, manpower and material resources.

[0004] The above problems are limited by working conditions. Traditional design and evaluation methods are difficult to meet the needs of system scanning effect evaluation. There is an urgent need for a scanning effect evaluation method that is versatile and easy to implement in engineering. Summary of the invention

[0005] In view of this, an embodiment of the present invention provides a ground evaluation device and method for the scanning effect of a long-term airborne platform to solve the technical problem that the scanning effect evaluation method in the prior art is difficult to meet the system scanning effect evaluation requirements. The method includes:

[0006] A ground evaluation device for scanning effect of a long-term airborne platform, comprising:

[0007] Data processor, servo control processor, three-axis test turntable and optoelectronic load;

[0008] The photoelectric load is installed on the three-axis test turntable, the servo control processor is electrically connected to the three-axis test turntable and the photoelectric load respectively, and the servo control processor is electrically connected to the data processor;

[0009] The servo control processor is used to collect entity data and transmit it to the servo control processor, wherein the entity data includes the measured attitude data of the carrier and the two-axis angle information data;

[0010] The data processor is used to receive entity data, and generate data calculation results through entity data, design data and virtual test scene data, and evaluate the scanning effect of the long-term airborne platform through the data calculation results;

[0011] The photoelectric load is used to receive the working instructions sent by the servo control processor, control the scanning work of the photoelectric load through the working instructions, and synchronously collect the axial motion information of the roll and pitch of the photoelectric load;

[0012] The three-axis test turntable is used to simulate the product's posture changes in the air.

[0013] Further, the servo control processor includes:

[0014] Sensor information acquisition module and work instruction scheduling module;

[0015] The sensor information acquisition module is used to collect the axial motion parameters of the photoelectric load, wherein the axial motion parameters include the roll angle and the pitch angle;

[0016] The work instruction scheduling module is used to send scanning instructions to the optoelectronic load, wherein the scanning instructions include rolling motion instructions and pitching motion instructions.

[0017] Furthermore, the data processing machine comprises:

[0018] Design data and virtual test scene injection module, physical data injection module, data measurement module and digital map matching and effect evaluation module. The data processor is used to evaluate the scanning effect of the airborne platform through design data, virtual test scene and physical data;

[0019] The design data and virtual test scenario injection module is used to inject the design data and virtual test scenario into the data calculation module;

[0020] The entity data injection module is used to inject entity data into the data calculation module;

[0021] The data calculation module is used to calculate and generate ground scanning coordinate points;

[0022] The digital map matching and effect evaluation module is used to match the ground scanning coordinate points with the digital map scene and simulate the scanning effect.

[0023] Furthermore, the photoelectric load includes:

[0024] Two-axis four-frame optoelectronic platform and optoelectronic payload sight axis;

[0025] The two-axis four-frame optoelectronic platform includes a roll axis and a pitch axis orthogonal to the roll axis.

[0026] A ground evaluation method for a scanning effect of a long-term airborne platform, wherein the ground evaluation method uses a ground evaluation device for the scanning effect of the long-term airborne platform to evaluate the scanning effect of the long-term airborne platform, comprising:

[0027] The following processing is performed until the scanning imaging of the planned area is completed:

[0028] Design ground scanning function algorithm;

[0029] Generate platform working data according to ground imaging requirements, execute platform working data on long-term space-based platforms, generate design data, use the design data as data to be evaluated, and use the ground scanning function algorithm to evaluate the data to be evaluated. If the evaluation requirements are not met, optimize and modify the ground scanning function algorithm;

[0030] The ground scanning work of the long-duration airborne platform is simulated on the ground, and the entity data generated by the scanning is used as the data to be evaluated. The ground scanning function algorithm is used to evaluate the data to be evaluated. If the evaluation requirements are not met, the ground scanning function algorithm is optimized and corrected.

[0031] Further, using the ground scanning function algorithm to evaluate the data to be evaluated includes:

[0032] Construct a virtual test scenario, which includes the working scenario parameters of the long-term airborne platform;

[0033] According to the data to be evaluated and the virtual test scene, the real-time coordinates of the geocentric coordinate system of the optoelectronic payload are calculated, and the real-time ground imaging position coordinates of the optoelectronic payload are calculated through the real-time coordinates of the geocentric coordinate system;

[0034] The real-time ground imaging position coordinates are matched with the digital map scene to generate a target scanning area map, and the ground imaging effect is evaluated through the target scanning area map. If the evaluation requirements are not met, the ground scanning function algorithm is optimized and corrected.

[0035] Furthermore, according to the data to be evaluated and the virtual test scene, the real-time coordinates of the geocentric coordinate system of the photoelectric payload are calculated, and the real-time ground imaging position coordinates of the photoelectric payload are calculated by the real-time coordinates of the geocentric coordinate system, including:

[0036] Calculate the real-time coordinates of the geocentric coordinate system of the optoelectronic payload Among them, the real-time coordinates is the transformation matrix from geographic coordinate system to geocentric coordinate system, is the initial coordinate of the geographic coordinate system of the photoelectric payload, is the speed parameter, t is the time;

[0037] The real-time coordinates of the geocentric coordinate system are used to calculate the real-time earth imaging position coordinates, where the real-time earth imaging position coordinates is the unit vector of the platform’s visual axis, r is the length of the observation vector, is the transformation matrix from the platform coordinate system to the geocentric coordinate system.

[0038] Furthermore, the ground imaging effect is evaluated through the target scanning area map, including:

[0039] Set the scanning imaging range required by the task, and determine whether the coverage of the target scanning area map meets the scanning imaging range required by the task;

[0040] Set the overlap rate of the mosaic images to determine whether the overlap rate between the target scanning area images is greater than the mosaic image overlap rate;

[0041] If the scanning imaging range does not meet the task requirements and / or is less than or equal to the mosaic overlap rate, the evaluation requirements are not met.

[0042] Furthermore, the overlap rate of the mosaic images is 15%.

[0043] Furthermore, the mission required a scanning imaging range of an area of ​​48km×48km.

[0044] Compared with the prior art, the at least one technical solution adopted in the embodiments of this specification can achieve the following beneficial effects:

[0045] By using the ground evaluation device of the embodiment of the present invention, the scanning effect of the long-term airborne platform can be evaluated on the ground, which has good versatility and is easy to be put into engineering practice. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0047] Figure 1 It is an overall structural diagram of a ground evaluation device for scanning effect of a long-term airborne platform according to an embodiment of the present invention;

[0048] Figure 2 It is a flow chart of a ground evaluation method for a scanning effect of a long-term airborne platform according to an embodiment of the present invention. DETAILED DESCRIPTION

[0049] The embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0050] The following describes the implementation methods of the present application through specific examples, and those skilled in the art can easily understand other advantages and effects of the present application from the contents disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The present application can also be implemented or applied through other different specific implementation methods, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that, in the absence of conflict, the following embodiments and the features in the embodiments can be combined with each other. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work belong to the scope of protection of the present application.

[0051] In an embodiment of the present invention, a ground evaluation device for the scanning effect of a long-term airborne platform is provided, such as Figure 1 As shown, the device comprises:

[0052] Data processor, servo control processor, three-axis test turntable and optoelectronic load;

[0053] The photoelectric load is installed on the three-axis test turntable, the servo control processor is electrically connected to the three-axis test turntable and the photoelectric load respectively, and the servo control processor is electrically connected to the data processor;

[0054] The servo control processor is used to collect entity data and transmit it to the servo control processor, wherein the entity data includes the measured attitude data of the carrier and the two-axis angle information data;

[0055] The data processor is used to receive entity data, and generate data calculation results through entity data, design data and virtual test scene data, and evaluate the scanning effect of the long-term airborne platform through the data calculation results;

[0056] The photoelectric load is used to receive the working instructions sent by the servo control processor, control the scanning work of the photoelectric load through the working instructions, and synchronously collect the axial motion information of the roll and pitch of the photoelectric load (two axial motion information);

[0057] The three-axis test turntable is used to simulate the posture changes of a long-term airborne platform in the air.

[0058] Wherein, the servo control processor includes:

[0059] Sensor information acquisition module and work instruction scheduling module;

[0060] The sensor information acquisition module is used to collect the axial motion parameters of the photoelectric load, wherein the axial motion parameters include the roll angle and the pitch angle;

[0061] The work instruction scheduling module is used to send scanning instructions to the optoelectronic load, wherein the scanning instructions include rolling motion instructions and pitching motion instructions.

[0062] The data processor includes:

[0063] Design data and virtual test scene injection module, physical data injection module, data measurement module and digital map matching and effect evaluation module. The data processor is used to evaluate the scanning effect of the airborne platform through design data, virtual test scene and physical data;

[0064] The design data and virtual test scenario injection module is used to inject the design data and virtual test scenario into the data calculation module;

[0065] The entity data injection module is used to inject entity data into the data calculation module;

[0066] The data calculation module is used to calculate and generate the coordinate points of the ground scan. The data calculation solves the position parameters (longitude, latitude, altitude) of the intersection of the visual axis on the ground through the position parameters, speed parameters, attitude parameters and motion parameters of the photoelectric load.

[0067] The digital map matching and effect evaluation module is used to match the ground scanning coordinate points with the digital map scene and simulate the scanning effect. Digital map matching is based on the position parameters (longitude, latitude, altitude) of the intersection of the visual axis on the ground, and the ground scene image is queried and matched to finally obtain the photoelectric load ground scanning scene image.

[0068] Among them, the optoelectronic payload includes:

[0069] A two-axis four-frame optoelectronic platform and an optoelectronic payload visual axis; the two-axis four-frame optoelectronic platform includes a roll axis and a pitch axis orthogonal to the roll axis.

[0070] Specifically, the optoelectronic payload adopts a two-axis four-frame optoelectronic platform, in which one axis is a roll axis and the other axis is a pitch axis orthogonal to the roll axis.

[0071] The scanning effect of the long-term airborne platform is evaluated using a ground evaluation device for the scanning effect of the long-term airborne platform, such as Figure 2 As shown in the figure, after receiving the scanning effect evaluation task, the design evaluation stage is first entered to design the functional algorithm, design and plan the scanning path, generate design data, and the data processor obtains the evaluation data for the data measurement module through the design data and virtual scene settings, calculates the ground scanning coordinates, and matches the digital map scene according to the coordinate points, and finally obtains the scanning imaging effect simulation. Compare the design indicators (ground scanning imaging range and mosaic overlap rate). If the requirements are not met, return to the functional algorithm (scanning path) design iteration. If the requirements are met, enter the entity evaluation stage.

[0072] In the entity evaluation stage, the servo control processor first controls the optoelectronic load to work and collect data. The data processor receives the entity data of the servo control processor (roll angle and pitch angle of the optoelectronic load during scanning imaging) and injects it into the data calculation module as evaluation input. The data calculation module calculates and predicts the coordinates of the ground scanning imaging points, and matches the coordinate points with the digital map scene to finally obtain the scanning imaging effect simulation. If the requirements (ground scanning imaging range and mosaic overlap rate) are not met, return to the functional algorithm design step for iterative optimization until the requirements are met.

[0073] Ground assessment methods include:

[0074] The following processing is performed until the scanning imaging of the planned area is completed:

[0075] Design a ground scanning function algorithm based on specific tasks; evaluate the ground scanning function algorithm in the design evaluation phase; and evaluate the ground scanning function algorithm in the physical evaluation phase.

[0076] Specifically, after receiving the mission from the mission machine, the design evaluation phase is first entered to design the ground scanning algorithm, design and plan the scanning path, generate design data, and the data processor obtains the evaluation data for the data measurement module through the design data and virtual scene settings, calculates the ground scanning coordinates, and matches the digital map scene according to the coordinate points, and finally obtains the simulation of the scanning imaging effect. Compare the design indicators. If the requirements are not met, return to the design iteration of the ground scanning algorithm. If the requirements are met, enter the entity evaluation phase.

[0077] The design assessment phase includes:

[0078] Plan the platform scanning trajectory according to the specific ground imaging requirements and generate platform working data. The specific data is the platform working instruction, that is, the platform scanning angle instruction. (Roll motion command roll cmd , pitch motion command pitch cmd );

[0079] According to the measured working environment characteristics, a virtual test scene is constructed, including the working scene parameters of the platform, including the coordinate parameters of the optoelectronic load geographic coordinate system (longitude lon0, latitude lat0, altitude alt0), speed parameters (Eastward speed v E , northward speed v N , celestial velocity v U ), attitude (roll angle φ, pitch angle θ, azimuth angle ψ);

[0080] Based on the design data and virtual test scenario, the real-time ground imaging position coordinates of the optoelectronic payload are calculated. The main steps are as follows:

[0081] 1) Obtain the real-time coordinates of the geocentric coordinate system of the photoelectric payload in, is the transformation matrix from geographic coordinate system to geocentric coordinate system, is the initial coordinate of the geographic coordinate system of the photoelectric load, and t is the time.

[0082] 2) Calculate the observation vector of the photoelectric payload pointing to the surface of the earth ellipsoid model (using the WGS84 ellipsoid model), and then obtain the real-time earth imaging position coordinates in, is the unit vector of the platform’s visual axis, r is the length of the observation vector, is the transformation matrix from the platform coordinate system to the geocentric coordinate system.

[0083] Combined with the earth ellipsoid equation, the length of the observation vector can be calculated and the real-time earth imaging position coordinates can be obtained.

[0084] According to the matching of the real-time ground imaging position coordinates and the digital map scene, the coordinate data is mapped to the digital map, the corresponding scene is extracted, and an imaging picture is obtained during the scanning process; this process is repeated again and again, and the images obtained by imaging during the entire scanning process are spliced ​​into a target scanning area map of the airborne platform.

[0085] On this basis, an evaluation of the ground imaging effect is carried out. Specific evaluation items include: whether the coverage of the target scanning area map meets the scanning imaging range required by the mission, and whether there is sufficient overlap between the mosaic images.

[0086] If the design index requirements are not met, return to the ground scanning function algorithm design for optimization and correction.

[0087] In the entity evaluation stage, the servo control processor first controls the optoelectronic load to work and collect data. The data processor receives the entity data of the servo control processor and injects it into the data calculation module as evaluation input. The data calculation module calculates and predicts the ground scanning coordinates and matches the coordinate points with the digital map scene to finally obtain the scanning imaging effect simulation. If the requirements are not met, the design steps of the ground scanning function algorithm are returned to iterative optimization until the requirements are met.

[0088] The ground scanning function algorithm is evaluated in the design evaluation phase, including:

[0089] Generate design data and virtual test scenes; calculate ground imaging coordinate points based on the design data and virtual test scenes; match ground imaging coordinate points with digital map scenes, and evaluate the ground imaging effect. If the evaluation requirements are not met, optimize and correct the ground scanning function algorithm.

[0090] The design data includes axial motion instructions of the roll axis and the pitch axis.

[0091] The virtual test scenario includes the position parameters (longitude, latitude, altitude), speed parameters (eastward speed, northward speed, celestial speed) and attitude (roll angle, pitch angle, azimuth angle) of the optoelectronic payload.

[0092] The physical evaluation phase of the ground scanning algorithm includes:

[0093] The photoelectric load is manipulated by the three-axis test turntable to collect data and obtain physical data; the physical data is injected into the data measurement module for re-evaluation; the ground imaging coordinate points are calculated based on the physical data and the virtual experimental scene; the ground imaging coordinate points are matched with the digital map scene, and the ground imaging effect is evaluated. If it does not meet the evaluation requirements, the ground scanning function algorithm is optimized and corrected.

[0094] Among them, the entity data includes the optoelectronic payload attitude parameters (roll angle, pitch angle, azimuth angle) and two axial motion parameters (roll angle, pitch angle).

[0095] The physical assessment phase includes:

[0096] The actual working posture changes of the stationary platform at high altitude are simulated by controlling the three-axis test turntable, and working data is collected simultaneously;

[0097] Input the data conditions designed in the design evaluation phase (including the scanning work instructions of the optoelectronic payload and the position and posture information of the airborne platform, etc.) into the airborne platform described in the entity for evaluation;

[0098] The coordinates of the ground imaging points are calculated during the scanning process based on the physical data, and then matched with the digital map scene based on the coordinate points;

[0099] Evaluate the ground imaging effect. If the scanning imaging range and the overlap rate of the mosaic image do not meet the requirements, return to the ground scanning function algorithm design for optimization and correction.

[0100] This process is repeated to determine whether the scanning and imaging algorithm has completed the scanning and imaging of the planned area and whether there is sufficient overlap between the scanned and spliced ​​images. If the requirements are not met, the platform scanning trajectory is adjusted for testing. If it is completed, the evaluation is completed. The evaluation items include the ground scanning imaging range and the overlap rate of the spliced ​​images. The ground scanning imaging range is the 48km×48km area below the stationed platform. The overlap rate of the spliced ​​images is required to be more than 15% to ensure that the images to be spliced ​​can be stably spliced ​​by the image algorithm.

[0101] The embodiments of the present invention achieve the following technical effects:

[0102] Through the ground evaluation device, the scanning effect of the long-term airborne platform can be evaluated on the ground, which has good versatility and is easy to practice in engineering. The ground evaluation method of the embodiment of the present invention adopts a method that combines virtuality and reality, integrates virtual scenes and actual working parameters of optoelectronic loads, so that the evaluation effect is closer to reality. The ground evaluation method of the embodiment of the present invention takes into account the simulation processing in the design stage, and can evaluate the effect in the design stage and correct the design in advance. The ground evaluation method of the embodiment of the present invention uses a digital map matching method to display the scanning effect, which is more intuitive to evaluate the scanning effect of the system. Compared with the traditional method, the ground evaluation device and method for the scanning effect of the long-term airborne platform of the embodiment of the present invention have the advantages of taking into account both design and entity evaluation, and the evaluation effect is close to the real working scene.

[0103] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the embodiments of the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A ground evaluation device for the scanning effect of a long-term airborne platform, characterized in that: include: Data processor, servo control processor, three-axis test turntable and optoelectronic load; The photoelectric load is mounted on the three-axis test turntable, the servo control processor is electrically connected to the three-axis test turntable and the photoelectric load, respectively, and the servo control processor is electrically connected to the data processor; The servo control processor is used to collect entity data and transmit it to the servo control processor, wherein the entity data includes carrier measured posture data and two-axis angle information data; The data processor is used to receive the entity data, and generate data calculation results through the entity data, design data and virtual test scene data, and evaluate the scanning effect of the long-term airborne platform through the data calculation results; The photoelectric load is used to receive the working instructions sent by the servo control processor, control the scanning work of the photoelectric load through the working instructions, and synchronously collect the axial motion information of the roll and pitch of the photoelectric load; The three-axis test turntable is used to simulate the posture changes of the long-term airborne platform in the air.

2. The ground evaluation device for scanning effect of a long-term airborne platform according to claim 1, characterized in that: The servo control processor comprises: Sensor information acquisition module and work instruction scheduling module; The sensor information acquisition module is used to collect the axial motion parameters of the photoelectric load, wherein the axial motion parameters include a roll angle and a pitch angle; The work instruction scheduling module is used to send a scanning instruction to the optoelectronic load, wherein the scanning instruction includes a rolling motion instruction and a pitching motion instruction.

3. The ground evaluation device for scanning effect of a long-term airborne platform according to claim 1, characterized in that: The data processing machine comprises: Design data and virtual test scene injection module, entity data injection module, data measurement module and digital map matching and effect evaluation module, the data processing machine is used to evaluate the scanning effect of the airborne platform through the design data, virtual test scene and entity data; The design data and virtual test scenario injection module is used to inject the design data and the virtual test scenario into the data calculation module; The entity data injection module is used to inject the entity data into the data calculation module; The data calculation module is used to calculate and generate ground scanning coordinate points; The digital map matching and effect evaluation module is used to match the ground scanning coordinate points with the digital map scene and simulate the scanning effect.

4. The ground evaluation device for scanning effect of a long-term airborne platform according to claim 1, characterized in that: The photoelectric load comprises: Two-axis four-frame optoelectronic platform and optoelectronic payload sight axis; The two-axis four-frame optoelectronic platform includes a roll axis and a pitch axis orthogonal to the roll axis.

5. A ground evaluation method for the scanning effect of a long-term airborne platform, wherein the ground evaluation method uses the ground evaluation device for the scanning effect of a long-term airborne platform according to any one of claims 1 to 4 to evaluate the scanning effect of the long-term airborne platform, characterized in that: include: The following processing is performed until the scanning imaging of the planned area is completed: Design ground scanning function algorithm; Generate platform working data according to ground imaging requirements, execute the platform working data on the long-term airborne platform, generate design data, use the design data as data to be evaluated, and use the ground scanning function algorithm to evaluate the data to be evaluated. If the evaluation requirements are not met, optimize and modify the ground scanning function algorithm; The ground scanning work of the long-duration airborne platform is simulated on the ground, and the entity data generated by the scanning is used as the data to be evaluated. The ground scanning function algorithm is used to evaluate the data to be evaluated. If the evaluation requirements are not met, the ground scanning function algorithm is optimized and corrected.

6. The ground evaluation method for the scanning effect of a long-term airborne platform according to claim 5, characterized in that: Using the ground scanning function algorithm to evaluate the data to be evaluated includes: Constructing a virtual test scene, wherein the virtual test scene includes working scene parameters of the long-term airborne platform; According to the data to be evaluated and the virtual test scene, the real-time coordinates of the geocentric coordinate system of the photoelectric payload are calculated, and the real-time ground imaging position coordinates of the photoelectric payload are calculated by the real-time coordinates of the geocentric coordinate system; The real-time ground imaging position coordinates are matched with the digital map scene to generate a target scanning area map, and the ground imaging effect is evaluated through the target scanning area map. If the evaluation requirements are not met, the ground scanning function algorithm is optimized and corrected.

7. The ground evaluation method for scanning effect of a long-term airborne platform according to claim 6, characterized in that: According to the data to be evaluated and the virtual test scene, the real-time coordinates of the geocentric coordinate system of the photoelectric payload are calculated, and the real-time ground imaging position coordinates of the photoelectric payload are calculated by the real-time coordinates of the geocentric coordinate system, including: Calculate the real-time coordinates of the geocentric coordinate system of the optoelectronic payload Among them, real-time coordinates is the transformation matrix from geographic coordinate system to geocentric coordinate system, is the initial coordinate of the geographic coordinate system of the photoelectric load, is the speed parameter, t is the time; Real-time coordinates based on the geocentric coordinate system Calculate the real-time ground imaging position coordinates Among them, the real-time ground imaging position coordinates is the unit vector of the platform’s visual axis, r is the length of the observation vector, is the transformation matrix from the platform coordinate system to the geocentric coordinate system.

8. The ground evaluation method for scanning effect of a long-term airborne platform according to claim 6, characterized in that: The ground imaging effect is evaluated by the target scanning area map, including: Set the scanning imaging range required by the task, and determine whether the coverage of the target scanning area map meets the scanning imaging range required by the task; Setting the overlap rate of mosaic images, and judging whether the overlap rate between the target scanning area images is greater than the mosaic image overlap rate; If the scanning imaging range does not meet the task requirements and / or is less than or equal to the mosaic overlap rate, the evaluation requirements are not met.

9. The ground evaluation method for scanning effect of a long-term airborne platform according to claim 8, characterized in that: The overlap rate of the mosaics is 15%.

10. The ground evaluation method for scanning effect of a long-term airborne platform according to claim 8, characterized in that: The task requires a scanning imaging range of an area of ​​48km×48km.

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