Aircraft seamless scanning stable imaging method

Abstract

The invention belongs to the field of optical remote sensing, and particularly relates to a seamless scanning stable imaging method for an aircraft. The precision of an optical axis geographic tracking point is calculated by introducing the minimum uncertainty of a system error so as to realize stable target tracking and clear imaging, a ground scanning range design model is established, the pointing error and the target size are overcome, a target colander is avoided, meanwhile, scanning design is performed according to ground parameters, and a ground scanning area is covered in a ploughing manner after multiple flights. The problem of target scanning omission in the single-route flight process can be solved, and the method is suitable for covering a ground scanning area in a ploughing mode after multiple flights; meanwhile, the method keeps the stability of the relative position relation between the aircraft and the target, has the advantage of clear imaging, is suitable for an intelligent recognition algorithm, and is also suitable for the condition that the integral time of a detector is relatively long, such as low-cost infrared imaging or visible light imaging during dawn and dusk.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of optical remote sensing, and particularly relates to a seamless scanning and stable imaging method for an aircraft. BACKGROUND

[0002] According to different observation requirements of an airborne photoelectric device, observation types are mainly divided into gazing observation and scanning search observation, the former is fixed-point observation on a known coordinate target or region, and the latter is wide-area observation on an unknown region. Compared with gazing observation, scanning search has advantages of wide observation region and fast observation speed, and is a more effective observation method for obtaining information right in advance. At present, most aircrafts adopt a periodic reciprocating motion mode to control the heading scanning of a photo imaging system servo platform. This scanning mode is simple and easy to control, however, in the process of aircraft movement, simple swing scanning is difficult to meet the observation requirements of geographical tracking stability, region full coverage and clear imaging. Therefore, it is of great practical application value to design a seamless scanning and stable imaging method suitable for an aircraft. SUMMARY

[0003] OBJECTIVE The application provides a seamless scanning and stable imaging method for an aircraft, which solves the problems of non-full coverage of an observation region and scanning imaging blur in the existing aircraft scanning technology.

[0004] TECHNICAL SCHEME A seamless scanning and stable imaging method for an aircraft, which calculates the precision of an optical axis geographical tracking point by introducing the minimum uncertainty of system error to realize stable target tracking and clear imaging, establishes a ground scanning range design model, overcomes pointing error and target size to avoid target sieve, and performs scanning design according to ground parameters, and ploughs the ground scanning region after multiple flights.

[0005] Further, the method comprises the following steps: Step one, acquiring real-time flight parameters of the aircraft: flight relative ground height, flight speed, flight position and imaging system servo frame angle.

[0006] Step two, considering the aircraft position error, attitude error and optical servo pointing error after system modeling, and then obtaining the precision of the imaging system optical axis geographical tracking point through theoretical calculation.

[0007] Step three, determining the gear shifting time according to the imaging system servo frame movement speed and the stable imaging working time of the aircraft.

[0008] Step four, obtaining the scanning overlap region width according to the minimum feature size of a typical target possibly existing in a predetermined target region and the precision of the optical axis geographical tracking point.

[0009] wherein For the width of the scanning overlap region, For the accuracy of the optical axis geographic tracking point, s is the minimum feature size of the typical target.

[0010] Step five, establish the scanning model of the servo heading frame 1) Ground imaging width model At a certain flight altitude, the aerial vehicle imaging system performs overhead imaging on the ground, and the field of view coverage area is approximately inverted trapezoidal, that is, the upper boundary imaging width is greater than the lower boundary imaging width. For the relative height of the aerial vehicle to the ground, For the angle between the optical axis of the imaging system and the ground, For the heading field of view angle of the imaging system, For the pitch field of view angle of the imaging system, For the slant distance between the intersection of the optical axis of the aerial vehicle imaging system and the ground and the aerial vehicle. Thus, the upper, middle and lower boundary widths of the ground imaging trapezoidal area can be obtained And the vertical distance from the aerial vehicle ground projection to the upper, middle and lower boundary of the imaging area ): 4) Ground imaging scanning angle model When the aerial vehicle imaging system scans, the servo frame will move, and is defined as the heading frame scanning angle, is the ground projection angle, that is, the ground imaging scanning angle, and L is the central chord length between the intersection of the optical axis and the ground before and after scanning.

[0011] 5) Calculation model of scanning parameters of adjacent gears 4) Along / vertical flight line distance model of geographic dotting Along-flight line distance of geographic scanning point:

[0012] Where t is the gear shifting time, that is, the time interval of one swing of the servo frame.

[0013] Vertical flight line distance of geographic scanning point:

[0014] 6) Calculation model of scanning field of view imaging width When the aerial vehicle scans horizontally, the sideslip angle represents the angle between the center of the scanning frame and the velocity direction. When the velocity vector is on the right of the symmetry plane of the aerial vehicle, the sideslip angle is positive, and vice versa.

[0015] ​When the imaging system field of view, ground overlap area width, flight relative height and scanning gear parameters are determined, the ground scanning imaging width of the heading frame and the position of the geographical scanning point relative to the flight line are calculated under different pitch angles by models 1) - 5).

[0016] Step six, according to the aircraft observation coverage task requirement binding input value ODSX and ODSZ, the corresponding heading and pitch scanning angle is obtained by backstepping according to the calculation model described in 1) - 4).

[0017] Further, it further comprises step seven, when the frame moves to the specified position, the geographical tracking point area is observed, and the aircraft intelligent recognition is started.

[0018] Further, the specific determination of the tracking point accuracy is: The current northeast sky position Eb, Nb of the aircraft, flight height, heading attitude angle , pitch attitude angle , roll attitude angle , imaging system servo heading frame angle EH and pitch frame angle EB are known, then the optical axis pointing target position deviation (Δx, Δy) from the aircraft position is respectively: Δx=-H*(cos(EB)cos(EH)cos( )sin( )+sin(EB)(cos( )sin( )- cos( )sin( )sin( )+cos(EB)sin(EH)(cos( )cos( )+sin( )sin( )sin( ))) / (cos( )cos( -cos(EB)cos( )sin(EH)sin( )+cos(EB)cos(EH)sin( )) Δy=-H*(cos(EB)cos(EH)cos( )cos( )+cos(EB)sin(EH)(cos( )sin( )sin( ) cos( )sin( ))+sin(EB)(-cos( )cos( )sin( )-sin( )sin( ))) / (cos( )cos( )sin(EB)-cos(EB)cos( )sin(EH)sin( )+cos(EB)cos(EH)sin( )) Without considering the height error, the geographical position accuracy (uNd, uEd) of the platform is: uNd=

[0019] uEd= The optical axis geographical tracking point accuracy is:

[0020] Where u represents the minimum uncertainty.

[0021] Further, in 1) of step five, the upper, middle and lower boundary widths of the imaging area are:

[0022]

[0023]

[0024] The vertical distance from the aircraft ground projection to the upper, middle and lower boundary of the imaging area is:

[0025]

[0026]

[0027] The field of view coverage depth is: .

[0029] Further, in 2) of step five, the ground imaging scan angle is calculated:

[0030]

[0031] Scan angle of adjacent gear of heading frame : .

[0033] Further, in 3) of step five, according to the ground overlapping area of the middle gear The scan angle of adjacent gear of heading frame can be obtained:

[0034] Scan angle of adjacent gear of ground imaging area:

[0035] n Total field of view of heading after scanning gear:

[0036] In the formula is the heading field of view angle of the imaging system, n is the scan gear, n 1, 2, 3,... The center of the field of view of the adjacent gear moves away from the ground by :

[0037] In the formula is the offset angle between the scan center and the flight speed vector.

[0038] Further, in 3) of step five, in order to meet the full coverage observation requirement of different size areas, the heading width of the observation region is divided into multiple blocks according to the ground projection of the field of view of the aircraft, and the platform servo scanning motion is divided into multiple gears.

[0039] Further, 5) of step five is specifically: The scan field of view of the aircraft is the ground imaging area. When the servo mechanism swings, the scan field of view will have three different relative position relationships with the flight speed vector, and the imaging width is determined by the length of the four corner points of the imaging area and the perpendicular line of the speed direction. The red dots are the four corner points of the ground imaging area. For the two left corner points closest to the ground projection of the speed direction and the two right corner points closest to the ground projection of the speed direction, if they are on both sides of the ground projection of the speed direction, the imaging width of the scan field of view is the sum of the distances on both sides, and if they are on the same side, the imaging width of the scan field of view is the difference between the distances on both sides.

[0040] The perpendicular distance D of each corner point to the speed direction, The distance from the ground projection point of the aircraft to the angle point, The ground imaging scanning angle in model ②, Which can be expressed by the following formula:

[0041] The ground imaging scanning angle Substituted into:

[0042] In the formula, The intersection angle of the heading frame angle boundary of the relative velocity direction. In the platform level flight attitude, the included angle relationship between the flight velocity vector, the scanning frame center vector and the scanning center (the center vector of the scanning area), so the frame angle of the left angle point is , and the frame angle of the right angle point is .

[0043] The distance from the lower left end point of the scanning field of view to the velocity direction:

[0044] The distance from the lower right end point of the scanning field of view to the velocity direction:

[0045] The distance from the upper left end point of the scanning field of view to the velocity direction:

[0046] The distance from the upper right end point of the scanning field of view to the velocity direction:

[0047] The angle point distribution is divided into three cases: 4 angle points are distributed on both sides of the velocity direction, 4 angle points are distributed on the left side of the velocity direction, and 4 angle points are distributed on the right side of the velocity direction. The imaging width of the scanning field of view in the three cases is respectively: Both sides

[0048] Left side

[0049] Right side .

[0051] Technical effects The application provides a seamless scanning stable imaging method of an aircraft, which considers target size and optical axis geographical tracking point accuracy when calculating a scanning overlap area, can overcome the problem of missing scanning targets in a single flight process, is suitable for ploughing type ground scanning area after multiple flights, maintains the stability of the relative position relationship between the aircraft and the target, has the advantage of clear imaging, is suitable for intelligent identification algorithms, and is also suitable for the case of long integration time of a detector, such as low-cost infrared imaging or visible light imaging during dawn and dusk. BRIEF DESCRIPTION OF DRAWINGS

[0052] Figure 1 is a ground imaging width model; Figure 2 is a ground imaging scanning angle range model; Figure 3 is a ground projection schematic diagram of a scanning field of view of different gears; Figure 4 is an adjacent gear overlap area calculation model; Figure 5 is an imaging width model of a scanning field of view; Figure 6 is a corner point position schematic diagram; Figure 7a is a left corner point frame angle schematic diagram; Figure 7b is a right corner point frame angle schematic diagram; Figure 8 is a work flow diagram of the seamless scanning stable imaging method of the aircraft. DETAILED DESCRIPTION

[0053] In order to make the purposes, technical solutions and advantages of the embodiments of the application clearer, the technical solutions in the embodiments of the application will be described in more detail below. In the examples, the same or similar reference signs represent the same or similar elements or elements with the same or similar functions throughout. The described embodiments are part of the embodiments of the application, rather than all the embodiments. The examples described below are exemplary and are intended to explain the application, and cannot be understood as limiting the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the application. The embodiments of the application will be described in detail below.

[0054] Figure 8 is a work flow schematic diagram of the seamless scanning stable imaging method of the aircraft provided by the application, as shown in Figure 8 The specific implementation steps of the seamless scanning stable imaging method of the aircraft provided by the application include the following contents: S1: Determine the aircraft observation area ground parameters, including the observation area width, the minimum feature size of the target in the area, the altitude, the scan gear shifting time, etc.

[0055] S2: Build a scanning observation device, install the servo frame and the speed, altitude, and attitude angle acquisition module on the aircraft. Install the optical imaging system on the servo frame. When the optical axis of the optical system is horizontal, the sum of the pitch angle of the aircraft attitude and the pitch angle of the servo frame is 0 degrees.

[0056] S3: After the aircraft is installed, calibrate the system installation error and the measurement error of each module.

[0057] S4: According to the above errors, determine the imaging system optical axis geographic tracking point precision.

[0058] S5: According to the imaging system optical axis geographic tracking point precision and the minimum feature size of the target in the observation area, determine the size of the adjacent gear overlapping area of the scanning area.

[0059] S6: After determining the size of the adjacent gear overlapping area, establish a servo heading frame scanning calculation model, including single field of view ground imaging width calculation, field of view coverage depth calculation, ground imaging scanning angle range calculation, geographic scanning point along / vertical flight line distance calculation, and scanning field of view imaging width calculation.

[0060] S7: Calculate the scanning field of view imaging width under different pitch angles using the model described in S6, and determine the geographic scanning point along / vertical flight line distance ODSX / ODSZ according to the observation width in S1.

[0061] S8: During the flight of the aircraft, real-time acquisition of the aircraft altitude, flight speed, and flight attitude angle state information data is performed through various sensor modules.

[0062] S9: Using the data in S8 and the model output in S7, the servo heading frame scanning calculation model in S6 is substituted back to obtain the motion law of the servo frame during the flight, and the imaging system is driven by the servo motor to perform periodic heading motion.

[0063] S10: When the center of the imaging system servo heading frame points to the geographic tracking point position, calculate the angle and speed compensation according to the real-time flight speed and attitude angle data of the aircraft to keep the line of sight angular velocity fixed for a period of time. During this period, the optical system imaging is clear and stable, and the observation effect is good.

[0064] Embodiment A seamless scanning and stable imaging method for an aircraft, which realizes stable target tracking and clear imaging by introducing the minimum uncertainty of system error to calculate the precision of the geographic tracking point of the optical axis, establishes a ground scanning range design model, overcomes pointing errors and target size to avoid target skimming, and can perform scanning design according to ground parameters, facilitating plow-type coverage of the ground scanning area after multiple flights. The method comprises the following steps: 1) Obtain real-time flight parameters of the aircraft: flight relative ground height, flight speed, flight position, imaging system servo frame angle, etc.

[0065] 2) According to the system modeling, consider the position error, attitude error and optical servo pointing error of the aircraft, and then obtain the precision of the imaging system optical axis geographic tracking point through theoretical calculation. The specific way to determine the tracking point precision is as follows: Given the current northeast sky position (Eb, Nb, H (flight height)) of the aircraft, the heading attitude angle , the pitch attitude angle , the roll attitude angle , the imaging system servo heading frame angle EH and the pitch frame angle EB, the deviation (Δx, Δy) of the optical axis pointing target position from the aircraft position is: Δx=-H*(cos(EB)cos(EH)cos( )sin( )+sin(EB)(cos( )sin( )- cos( )sin( )sin( )+cos(EB)sin(EH)(cos( )cos( )+sin( )sin( )sin( ))) / (cos( )cos( -cos(EB)cos( )sin(EH)sin( )+cos(EB)cos(EH)sin( )) Δy=-H*(cos(EB)cos(EH)cos( )cos( )+cos(EB)sin(EH)(cos( )sin( )sin( )- cos( sin( ))+sin(EB)(-cos( cos( sin( )-sin( sin( ))) / (cos( cos( sin(EB)-cos(EB)cos( )sin(EH)sin( )+cos(EB)cos(EH)sin( )) Ignoring altitude error, the platform's geographic location accuracy (uNd, uEd) is: uNd=

[0066] uEd= Then the accuracy of the optical axis geographic tracking point for:

[0067] Where u represents the minimum uncertainty: 3) Determine the shift time based on the motion speed of the imaging system's servo frame and the aircraft's stable imaging working time.

[0068] 4) The width of the scanning overlap area is obtained based on the minimum feature size of typical targets that may exist in the predetermined target area and the accuracy of the optical axis geographic tracking point:

[0069] in To scan the width of the overlapping region, denoted as the accuracy of the optical axis geographic tracking point, and s as the minimum feature size of a typical target.

[0070] 5) Establish a servo heading frame scanning model At a certain flight altitude, the ground imaging width model shows that when an aircraft's imaging system performs a top-down image of the ground, its field of view is approximately inverted trapezoidal, meaning the upper boundary imaging width is greater than the lower boundary imaging width. For example... Figure 1 As shown in the figure The altitude of the aircraft relative to the ground. The angle between the optical axis of the imaging system and the ground. For the imaging system's heading field of view, The pitch field of view of the imaging system. The intersection of the optical axis of the aircraft imaging system and the ground and the slant distance between the aircraft. Thus, the upper, middle and lower boundary width of the ground imaging trapezoidal area (Wu, Wm, Wl) and the vertical distance of the aircraft ground projection to the upper, middle and lower boundary of the imaging area (Hg, Hm, Hl) can be obtained. : The upper, middle and lower boundary width of the imaging area:

[0071]

[0072]

[0073] The vertical distance of the aircraft ground projection to the upper, middle and lower boundary of the imaging area:

[0074]

[0075]

[0076] The depth of the field of view coverage: :

[0077] When the aircraft imaging system scans, the servo frame will move, defining as the heading frame scan angle, as the ground projection angle of , i.e. the ground imaging scan angle, and L as the central chord length between the intersection of the optical axis before and after scanning and the ground.

[0078] The ground imaging scan angle is calculated as: :

[0079]

[0080] The heading frame scan angle is obtained as: :

[0081] Adjacent gear scan parameter calculation model In order to meet the full coverage observation requirements of different size areas, the heading width of the observation area is divided into multiple blocks according to the ground projection of the field of view of the aircraft, and the platform servo scanning motion is divided into multiple gears. The blue box area in the above figure is the ground projection of the scan field of view of three different gears.

[0082] According to the ground overlap area Figure 4 in the above, , the adjacent gear scan angle of the heading frame angle can be obtained:​

[0083] Ground imaging area adjacent gear scanning angle:

[0084] n Total field of view after scanning a gear:

[0085] In the formula is the imaging system heading field of view angle, n is the scanning gear, n 1,2,3,... The center of the field of view of the adjacent gear moves a distance of :

[0086] In the formula is the offset angle between the scanning center and the flight speed vector.

[0087] Along / vertical line distance model of geographical scanning point along the line distance:

[0088] Where t is the gear shifting time, that is, the time interval for the servo frame to swing once.

[0089] Vertical line distance of geographical scanning point:

[0090] Scan field of view imaging width calculation model When the aircraft is scanning in a flat flight, the sideslip angle represents the angle between the scanning frame center (heading frame angle 0 degrees) and the speed direction. When the speed vector is on the right side of the aircraft symmetry plane, the sideslip angle is positive, and vice versa.

[0091] The aircraft scanning field of view is the ground imaging area. When the servo mechanism swings, the scanning field of view will have three different relative positions with the aircraft speed vector, and the imaging width is determined by the length of the four corner points of the imaging area and the perpendicular line to the speed direction. As shown in Figure 5 , the red dots are the four corner points of the ground imaging area. For the two left corner points closest to the speed direction ground projection and the two right corner points closest to the speed direction ground projection, if they are on both sides of the speed direction ground projection, the scanning field of view imaging width is the sum of the two distances, and if they are on the same side, the scanning field of view imaging width is the difference between the two distances.

[0092] The perpendicular distance D of each corner point to the speed direction is shown as follows Figure 6 , the distance from the corner point to the velocity direction, the ground imaging scan angle in model ②, which can be expressed by the following formula:

[0093] the ground imaging scan angle is substituted into which can be obtained:

[0094] wherein, is the intersection angle of the heading frame angle boundary of the relative velocity direction. Figure 7a and Figure 7b represents the angle relationship between the flight velocity vector, the scan frame center vector and the scan center (the center vector of the scan area) in the platform level flight attitude, so the frame angle of the left corner point is and the frame angle of the right corner point is .

[0095] the distance from the lower left end point of the scan field of view to the velocity direction:

[0096] the distance from the lower right end point of the scan field of view to the velocity direction:

[0097] the distance from the upper left end point of the scan field of view to the velocity direction:

[0098] the distance from the upper right end point of the scan field of view to the velocity direction:

[0099] The corner point distribution is divided into three cases: 4 corner points are distributed on both sides of the velocity direction, 4 corner points are distributed on the left side of the velocity direction, and 4 corner points are distributed on the right side of the velocity direction. The imaging widths of the scan field of view in the three cases are respectively: both sides

[0100] left side

[0101] right side

[0102] When the imaging system field of view, the ground overlap area width, the flight relative height and the scan gear and other parameters are determined, the heading frame scan ground imaging width and the position of the geographical scan point (the frame center pointing point) relative to the flight line under different pitch angles can be calculated through models ①-⑤.

[0103] 6) According to the aircraft observation coverage task requirement, the input values ODSX and ODSZ are bound, and the corresponding heading and pitch scanning angles are obtained according to the calculation model described in ①-④.

[0104] 7) When the frame moves to the specified position, the geographic tracking point area is observed, and the aircraft intelligent recognition is started.

[0105] In addition, unless otherwise defined, the technical terms or scientific terms used in the description of the present application should be the general meaning understood by the general technical personnel in the field to which the present application belongs. The words indicating the direction or position relationship such as "up", "down", "left", "right", "center", "vertical", "horizontal", "inner", "outer" and the like used in the description of the present application are only used to indicate the relative direction or position relationship, and not to imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation, and the relative position relationship may also change accordingly when the absolute position of the described object changes, therefore it cannot be understood as a limitation on the present application. The "first", "second", "third" and the like used in the description of the present application are only for the purpose of description, to distinguish different components, and cannot be understood as indicating or implying relative importance. The "one", "a" or "the" and the like used in the description of the present application should not be understood as an absolute limitation on the quantity, but should be understood as the existence of at least one. The "includes" or "contains" and the like used in the description of the present application means that the elements or objects appearing before the word are covered by the elements or objects listed after the word and their equivalents, without excluding other elements or objects.

[0106] In addition, it should be further pointed out that, unless otherwise explicitly specified and limited, the "installation", "connection", "connection" and the like used in the description of the present application should be understood in a broad sense, for example, the connection can be fixed connection, or detachable connection, or integrally connected; can be mechanical connection, or electrical connection; can be directly connected, or indirectly connected through intermediate medium, or the internal communication of two elements, and those skilled in the art can understand the specific meaning of the present application according to the specific circumstances.

[0107] The above is only a specific embodiment of the present application and is not used to limit the present application. Any skilled person in the art can make changes or modifications to the equivalent embodiments applied to other fields within the spirit and principles of the present application, but any simple modification, equivalent change and improvement made to the above embodiments according to the technical essence of the present application should be included in the protection scope of the present application.

Claims

1. A seamless scanning stabilized imaging method for aircraft, characterized in that, By introducing the minimum uncertainty of systematic error, the accuracy of the optical axis geographic tracking point is calculated to achieve stable target tracking and clear imaging. A ground scanning range design model is established to overcome pointing errors and target size to avoid target leakage. At the same time, scanning design is carried out according to ground parameters, and the ground scanning area is covered in a plow-like manner after multiple flights.

2. The method as described in claim 1, characterized in that, Includes the following steps: Step 1: Obtain real-time flight parameters of the aircraft: flight altitude relative to the ground, flight speed, flight position, and servo frame angle of the imaging system; Step 2: After modeling the system, consider the aircraft's position error, attitude error, and optical servo pointing error, and then use theoretical calculations to obtain the accuracy of the imaging system's optical axis geographic tracking point. Step 3: Determine the shift time based on the motion speed of the imaging system's servo frame and the aircraft's stable imaging operation time; Step 4: Obtain the width of the scanning overlap area based on the minimum feature size of typical targets that may exist in the predetermined target area and the accuracy of the optical axis geographic tracking points. in To scan the width of the overlapping region, is the accuracy of the optical axis geographic tracking point, and s is the minimum feature size of a typical target; Step 5: Establish the servo heading frame scanning model 1) Ground imaging width model; At a certain flight altitude, the aircraft imaging system performs downward imaging of the ground, and its field of view coverage area is approximately inverted trapezoidal, that is, the upper boundary imaging width is greater than the lower boundary imaging width. The altitude of the aircraft relative to the ground. The angle between the optical axis of the imaging system and the ground. For the imaging system's heading field of view, The pitch field of view of the imaging system. Let the intersection of the optical axis of the aircraft imaging system and the ground, and the slant distance between the ground and the aircraft, be the points where the optical axis intersects with the ground and the slant distance between the ground and the ground. From this, the widths of the upper, middle, and lower boundaries of the trapezoidal region of the ground imaging can be obtained. The vertical distance between the upper, middle and lower boundaries of the imaging area and the ground projection of the aircraft on the ground : 2) Ground imaging scanning angle model When the aircraft imaging system scans, the servo frame moves, defining... For the heading frame scan angle, for The ground projection angle is the ground imaging scanning angle, and L is the center chord length between the intersection of the optical axis and the ground before and after scanning; 3) Calculation model for adjacent gear scanning parameters 4) Geographic point distance model along / perpendicular to the flight path Distance of geographic scan point along flight path: in t The shift time is the time interval between one swing of the servo frame. Vertical distance of geographic scan point: 5) Calculation model for scanning field of view imaging width During level flight scanning, sideslip angle The sideslip angle represents the angle between the center of the scanning frame and the velocity direction. When the velocity vector is to the right of the aircraft's plane of symmetry, the sideslip angle is positive, and vice versa. When the field of view of the imaging system, the width of the ground overlap area, the relative flight altitude and the scanning gear parameters are determined, the width of the ground imaging scanned by the heading frame and the position of the geographic scanning point relative to the flight path are calculated at different pitch angles using models 1)-5). Step 6: Based on the requirements of the aircraft observation coverage mission, input values ​​ODSX and ODSZ are set, and the corresponding heading and pitch scanning angles are obtained by back-calculation using the calculation models described in 1)-4).

3. The method as described in claim 2, characterized in that, It also includes step seven, which involves observing the geographic tracking point area and enabling intelligent recognition of the aircraft when the frame moves to the designated position.

4. The method as described in claim 2, characterized in that, Step two, specifically, involves determining the tracking point accuracy as follows: Given the aircraft's current northeastern sky position Eb, Nb, H, flight altitude, heading, and attitude angle... Pitch angle Roll attitude angle Given the servo heading frame angle EH and pitch frame angle EB of the imaging system, the deviations (Δx, Δy) between the optical axis pointing towards the target position and the aircraft position are respectively: Δx=-H*(cos(EB)cos(EH)cos( )without( )+sin(EB)(cos( )without( )- cos( )without( )without( )+cos(EB)sin(EH)(cos( )cos( )+sin( )without( )without( ))) / (cos( )cos( -cos(EB)cos( )sin(EH)sin( )+cos(EB)cos(EH)sin( )) Δy=-H*(cos(EB)cos(EH)cos( )cos( )+cos(EB)sin(EH)(cos( )without( )without( )- cos( )without( ))+sin(EB)(-cos( )cos( )without( )-without( )without( ))) / (cos( )cos( )sin(EB)-cos(EB)cos( )sin(EH)sin( )+cos(EB)cos(EH)sin( )) Ignoring altitude error, the platform's geographic location accuracy (uNd, uEd) is: uNd= uEd= Then the accuracy of the optical axis geographic tracking point for: Where u represents the minimum uncertainty.

5. The method as described in claim 2, characterized in that, In step 5, 1), the widths of the upper, middle, and lower boundaries of the imaging region are: Vertical distance from the upper, middle, and lower boundaries of the imaging area to the aircraft's ground projection: Depth of field of view : 。 6. The method as described in claim 2, characterized in that, In step 5, 2), the ground imaging scanning angle is calculated. : Obtain the scanning angle of the heading frame : 。 7. The method as described in claim 2, characterized in that, In step 5, 3), based on the overlapping area of ​​the ground... The adjacent gear scanning angles of the heading frame angle are obtained: Scanning angles of adjacent positions in the ground imaging area: n Total field of view after file scan: In the formula For the imaging system's heading field of view, n For scanning position, n 1,2,3,... Ground distance of movement of the field of view center of adjacent gears : In the formula This is the offset angle between the scan center and the flight velocity vector.

8. The method as described in claim 2, characterized in that, In step 5, 3), in order to meet the full coverage observation requirements of areas of different sizes, the observation area is divided into multiple sections according to the ground projection of the aircraft's field of view, and the corresponding platform servo scanning motion is divided into multiple levels.

9. The method as described in claim 2, characterized in that, Step 5, 5) specifically refers to: The scanning field of view of the aircraft is the ground imaging area. When the servo mechanism swings, the scanning field of view will have three different relative positional relationships with the aircraft's velocity vector. Its imaging width is determined by the length of the four corner points of the imaging area and the perpendicular line of the velocity direction. The red dots are the four corner points of the ground imaging area. For the two left corner points and the two right corner points that are closest to the ground projection in the velocity direction, if they are on both sides of the ground projection in the velocity direction, the imaging width of the scanning field of view is the sum of the distances on both sides. If they are on the same side, the imaging width of the scanning field of view is the difference between the distances on both sides. The perpendicular distance D from each corner point to the velocity direction, The distance from the ground projection point of the aircraft to the corner point. The ground imaging scanning angle in model ② It can be expressed as follows: Ground imaging scanning angle Substituting, we get: In the formula, The angle between the relative velocity direction and the heading frame angle boundary; the angle relationship between the flight velocity vector, the scanning frame center vector, and the scanning center (the center vector of the scanned area) under level flight attitude; therefore, the frame angle at the left corner point is... The frame angle of the right corner point is ; The distance from the lower left end of the scanning field of view to the velocity direction: The distance from the lower right endpoint of the scanning field of view to the velocity direction: The distance from the upper left end of the scanning field of view to the velocity direction: The distance from the upper right endpoint of the scanning field of view to the velocity direction: The corner point distribution is divided into three cases: four corner points distributed on both sides of the velocity direction, four corner points distributed on the left side of the velocity direction, and four corner points distributed on the right side of the velocity direction; the scanning field of view imaging widths for the three cases are as follows: Both sides: Left side: Right side: .

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