Microwave remote sensing ground calibration target positioning device and target positioning method

Abstract

The present application belongs to the field of remote sensing, and provides a microwave remote sensing ground calibration target installation device and a target installation method. When installing the target, the installation frame is supported on the ground, so that the plane where the azimuth pointer is located is parallel to the horizontal plane. The azimuth pointer is adjusted to an angle parallel to the designed flight path of the aircraft, and the pitch angle pointer is adjusted to a position parallel to the perpendicular line of the calibration point and the designed flight path. With the first reference component and the second reference component as references, the target is moved to a position where the azimuth reference line is attached to the first reference component, and at the same time, the target is moved to a position where the pitch angle reference surface is attached to the second reference component. The target installation device provided by the present application integrates the azimuth calibration component and the pitch angle calibration component into a whole structure, which can provide references for the azimuth and the pitch angle at the same time, and the problem that the first parameter changes when adjusting the second parameter after adjusting the first parameter does not occur.

Description

Technical Field

[0001] This invention relates to the field of remote sensing technology, and in particular to a microwave remote sensing ground calibration target placement device and target placement method. Background Technology

[0002] In microwave remote sensing ground calibration, determining the radar cross-section (RCS) of the ground target is crucial. In practice, corner reflectors are often used as ground calibration targets. Errors in the manufacturing of corner reflectors can cause RCS errors, while errors in position and orientation during installation can affect the microwave incident angle, causing it to deviate from the direction of maximum RCS, thus impacting calibration accuracy. Generally, once the corner reflector is finalized during ground calibration, its manufacturing errors cannot be changed. The only way to mitigate these effects and improve calibration accuracy is to ensure sufficiently precise position and orientation during installation.

[0003] During corner reflector installation, technicians first select a calibration field and calibration point based on the designed flight path and remote sensing imagery. Then, using the 3D information of the calibration point, flight altitude, and designed flight path, they calculate the azimuth and elevation angles of the corner reflector. For example, when the base of the corner reflector is triangular, the azimuth angle ensures that the base of the corner reflector furthest from the calibration point is parallel to the flight path, and the elevation angle ensures that the perpendicular line from the calibration point to the designed flight path coincides with the perpendicular line from the base of the corner reflector furthest from the calibration point.

[0004] To meet these two requirements, a level and a compass are typically used. The level measures the pitch angle of the corner reflector's base, while the compass, with its automatic north-pointing function, measures the azimuth angle. However, because the two instruments operate independently and the two measurement steps are performed separately, adjusting the first parameter often results in a change in the first parameter when adjusting the second, requiring multiple adjustments to barely meet the requirements. This installation method leads to low accuracy, long time consumption, and severely impacts installation efficiency and quality. Summary of the Invention

[0005] This invention provides a microwave remote sensing ground calibration target placement device and method. Addressing the shortcomings of existing technologies that use separate levels and compasses for corner reflector installation, where adjusting one parameter leads to changes in another, requiring repeated adjustments, this invention achieves the effect of providing both azimuth and elevation angle references in a single microwave remote sensing ground calibration target placement device. Furthermore, through attitude transmission, it addresses the difficulty of placing large, heavy, and multi-shaped corner reflectors, transforming the cumbersome placement process of directly placing targets of different sizes into a rapid adjustment process using the device itself. This solves the practical difficulty of quickly and accurately installing targets of different specifications in the field.

[0006] This invention provides a microwave remote sensing ground calibration target placement device, comprising:

[0007] Mounting bracket, the bottom end of which is used for support on the ground;

[0008] An azimuth calibration component includes an azimuth measuring device and a first reference component. The azimuth measuring device is mounted on the mounting frame, and the first reference component is connected to the azimuth pointer of the azimuth measuring device. The first reference component is used to provide a reference for the azimuth reference line of the target.

[0009] The pitch angle calibration component includes a pitch angle measuring device and a second reference component. The pitch angle measuring device is mounted on the mounting bracket, and the second reference component is connected to the pitch angle pointer of the pitch angle measuring device. The second reference component is used to provide a reference for the pitch angle reference surface of the target.

[0010] According to the microwave remote sensing ground calibration target placement device provided by the present invention, the azimuth measuring device includes:

[0011] The first dial is rotatably connected to the mounting bracket, and when the mounting bracket is supported on the ground, the first dial is parallel to the horizontal plane.

[0012] A compass, which is rotatably connected to the mounting bracket;

[0013] The proximal end of the azimuth pointer is rotatably connected to the mounting bracket;

[0014] The rotation axes of the compass and the azimuth pointer are both collinear with the rotation axis of the first dial.

[0015] According to the microwave remote sensing ground calibration target placement device provided by the present invention, the first reference component includes a first reference rod and a connecting rod. The first reference rod is connected to the distal end of the azimuth pointer through the connecting rod, and the first reference rod is parallel to the azimuth pointer.

[0016] According to the microwave remote sensing ground calibration target placement device provided by the present invention, the elevation angle measuring device includes:

[0017] The second dial is fixedly connected to the mounting bracket, and when the mounting bracket is supported on the ground, the second dial is perpendicular to the horizontal plane.

[0018] The distal end of the pitch angle pointer is rotatably connected to the center of the second dial, and the axis of rotation is perpendicular to the second dial.

[0019] According to the microwave remote sensing ground calibration target placement device provided by the present invention, the second reference component includes a second reference rod, the second reference rod is collinear with the pitch angle pointer, one end of the second reference rod is connected to the proximal end of the pitch angle pointer, and the other end of the second reference rod extends in a direction away from the distal end of the pitch angle pointer.

[0020] According to the microwave remote sensing ground calibration target placement device provided by the present invention, the mounting frame is a telescopic rod.

[0021] According to the microwave remote sensing ground calibration target placement device provided by the present invention, damping components are provided between the azimuth pointer, the first scale dial, the elevation pointer and the mounting frame.

[0022] According to the microwave remote sensing ground calibration target placement device provided by the present invention, a level is provided on the first dial and / or the second dial.

[0023] The present invention also provides a target placement method, which uses the microwave remote sensing ground calibration target placement device as described above to provide a reference for target placement. The target placement method includes the following steps:

[0024] Support the bottom of the mounting bracket on the ground, so that the azimuth measuring device is parallel to the horizontal plane and the pitch measuring device is perpendicular to the horizontal plane.

[0025] Adjust the azimuth pointer so that it points parallel to the aircraft's designed flight path;

[0026] Adjust the pitch angle pointer so that it points parallel to the vertical line of the designed flight path, and the vertical line passes through the calibration point of the target;

[0027] The target is installed with reference to the positions of the first reference component and the second reference component.

[0028] According to the target placement method provided by the present invention, the installation of the target with reference to the positions of the first reference component and the second reference component includes the following steps:

[0029] Adjust the target so that the azimuth reference line is parallel to the end of the first reference component that is furthest from the azimuth pointer;

[0030] The target is adjusted to a position where the pitch angle reference plane is parallel to the second reference component.

[0031] The microwave remote sensing ground calibration target mounting device provided by this invention includes a mounting frame, an azimuth calibration component, and an elevation calibration component. The azimuth calibration component includes an azimuth measuring device and a first reference component. The azimuth measuring device is mounted on the mounting frame and includes an azimuth pointer. One end of the first reference component is connected to the azimuth pointer, and the other end of the first reference component provides a reference for the azimuth reference line of the target. The elevation calibration component includes an elevation measuring device and a second reference component. The elevation measuring device is also mounted on the mounting frame and includes an elevation pointer. One end of the second reference component is connected to the elevation pointer, and the other end of the second reference component provides a reference for the elevation reference surface of the target. During installation, the mounting frame is supported on the ground, ensuring that the plane containing the azimuth pointer is parallel to the horizontal plane, and simultaneously ensuring that the plane containing the elevation pointer is perpendicular to the horizontal plane. Referring to the azimuth measuring device, adjust the azimuth pointer to an angle parallel to the aircraft's designed flight path. Referring to the pitch measuring device, adjust the pitch pointer to a position perpendicular to the designed flight path, and ensure the pitch pointer points towards the target's calibration point. Using the first and second reference components as references, move the target to a position where the azimuth reference line aligns with the end of the first reference component furthest from the azimuth pointer, and simultaneously move the target to a position where the pitch reference surface aligns with the second reference component. The target installation device provided by this invention integrates the azimuth and elevation calibration components into a single structure, which can be fixed on the ground and simultaneously provide references for both azimuth and elevation angles. The two angles can be mutually checked, ensuring that the attitude of the corner reflector can be checked at any time during installation. This avoids the problem of the first parameter changing when adjusting the second parameter after adjusting the first parameter. Through the attitude transmission of this device, it addresses the difficulty of installing large, heavy, and multi-shaped corner reflectors, transforming the original cumbersome installation operation of targets of different sizes into a rapid adjustment operation of this device, thus solving the practical difficulty of quickly and accurately installing targets of different specifications in the field.

[0032] Furthermore, the target placement method provided by the present invention uses the microwave remote sensing ground calibration target placement device as described above for placement, and therefore has the same advantages as described above. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0034] Figure 1 This is a schematic diagram of the triangular pyramidal reflector provided by the present invention;

[0035] Figure 2 This is a front view of the microwave remote sensing ground calibration target placement device provided by the present invention;

[0036] Figure 3 This is a left view of the microwave remote sensing ground calibration target placement device provided by the present invention;

[0037] Figure 4 This is a top view of the azimuth calibration component provided by the present invention;

[0038] Figure label:

[0039] 100: Corner reflector; 110: Azimuth reference line; 120: Pitch reference surface; 200: Mounting bracket; 300: Azimuth calibration assembly; 310: Azimuth measuring device; 311: First dial; 312: Compass; 313: Azimuth pointer; 320: First reference assembly; 321: First reference rod; 322: Connecting rod; 400: Pitch calibration assembly; 410: Pitch measuring device; 411: Second dial; 412: Pitch pointer; 420: Second reference assembly; 421: Second reference rod; 500: Level. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0041] After years of development, remote sensing has evolved from qualitative to quantitative remote sensing. Calibration is the prerequisite and foundation for conducting quantitative remote sensing. In microwave remote sensing, calibration work can be broadly divided into two categories: radiometric calibration and polarimetric calibration. Calibration is an indispensable step in achieving quantitative Earth observations via microwave remote sensing. Calibration is typically divided into point target calibration and area target calibration. Point targets refer to small ground features, such as small cars or metal signs, while area targets are targets with a certain distribution area and stable scattering, such as large, untouched, flat desert surfaces. Because finding ideal area targets is difficult, microwave remote sensing ground calibration generally uses point targets.

[0042] Taking microwave remote sensing radiometric calibration as an example, microwave remote sensing radiometric calibration is the process of calibrating the ability of a microwave remote sensing system to measure the amplitude and phase of the backscattered signal of a target and establishing the correspondence between them. That is, constructing an accurate relationship between the backscattering coefficient of the image and the ground object, it is a prerequisite for the quantitative application of microwave remote sensing, and its calibration accuracy directly affects the scope of subsequent data use.

[0043] Ground calibration of point targets in microwave remote sensing is generally performed using a corner reflector 100. The corner reflector 100 has a relatively stable and large radar cross-section and exhibits a 3dB beamwidth independent of wavelength and size. Therefore, the corner reflector 100 has become a commonly used calibration device in microwave remote sensing radiometric calibration.

[0044] In microwave remote sensing ground calibration, determining the radar cross-section (RCS) of the corner reflector 100 is crucial. Errors in the manufacturing of the corner reflector 100 will cause RCS errors, while errors in position and orientation during installation will affect the microwave incident angle, causing it to deviate from the direction of maximum RCS, thus impacting the calibration results. Generally, once the corner reflector 100 is finalized during ground calibration, its manufacturing errors cannot be changed. The only way to mitigate these effects and improve calibration accuracy is to ensure sufficiently precise position and orientation during installation.

[0045] To minimize installation impact, the following principles should generally be followed when installing corner reflectors 100:

[0046] First, adjust the azimuth reference line of the corner reflector 100 so that the azimuth reference line is parallel to the design flight path of the aircraft. Taking the triangular cone corner reflector as an example, the edge line of the base plate on the opening side is the azimuth reference line.

[0047] Second, adjust the elevation angle of the corner reflector 100 according to the incident angle of the radar wave, so that the perpendicular line of the side line of the base plate of the corner reflector 100 on the opening side is parallel to the perpendicular line of the designed route passing through the calibration point.

[0048] Third, ensure that the base of the corner reflector 100 (if any) is not visible and that the base portion does not receive radar waves.

[0049] Fourth, the corner reflector 100 should be placed in a location with weak background reflectivity to facilitate the extraction of its position from microwave remote sensing images.

[0050] Fifth, corner reflectors 100 should be installed as far away as possible from objects that are prone to multipath effects.

[0051] The general installation process of an angle reflector is as follows: After receiving the designed flight path, technicians, in conjunction with remote sensing imagery, select a calibration field and determine the calibration point. Based on the three-dimensional information of the calibration point, flight altitude, and designed flight path, they calculate the azimuth and elevation angles of the angle reflector 100. The azimuth angle ensures that the bottom edge of the angle reflector 100 on the open side is parallel to the designed flight path, and the elevation angle ensures that the perpendicular line from the bottom edge of the angle reflector 100 on the open side is parallel to the perpendicular line of the designed flight path passing through the calibration point. To achieve these two requirements, a level 500 and a compass are typically used. The level 500 can measure the elevation angle of the bottom edge of the angle reflector 100, and the compass has an automatic north-pointing function and can measure the azimuth angle of the bottom edge of the angle reflector.

[0052] Corner reflectors 100 come in various specifications, such as trihedral and dihedral, and vary in size from 0.3 meters to 1.4 meters. They are also available with and without bases, and their weight varies considerably, with some weighing over 100 kilograms. The traditional method of installing corner reflectors 100 involves directly using relevant instruments to adjust their azimuth and elevation angles according to the design parameters, which is a difficult task.

[0053] Specifically, each installation involves first adjusting the azimuth using a compass, then adjusting the elevation using a 500° level, and finally fixing the positions. Because the two instruments are independent and the two steps are separate, adjusting one parameter often results in the other changing, requiring multiple repetitions to barely meet the requirements, and necessitating at least two people to complete the task. This leads to two problems: low accuracy and low time and efficiency. During deployment, situations often arise where the design does not meet the third, fourth, or fifth requirements, necessitating temporary relocation of the installation location, significantly increasing the workload. Considering the safety of the corner reflector 100, there are also situations where it needs to be temporarily installed during testing, posing new challenges to installation efficiency and time, often requiring increased manpower or sacrificing the installers' rest time. In these cases, the aforementioned two problems become even more pronounced.

[0054] This invention provides a microwave remote sensing ground calibration target placement device and method. Addressing the shortcomings of existing technologies that use separate levels and compasses for reference during the installation of corner reflectors 100, where adjusting one parameter leads to changes in another, requiring repeated adjustments, this invention achieves the effect of providing references for both azimuth and elevation angles in a single microwave remote sensing ground calibration target placement device. Furthermore, through attitude transmission, it addresses the difficulty of placing large, heavy, and multi-shaped corner reflectors, transforming the cumbersome placement process of directly placing targets of different sizes into a rapid adjustment process using the device itself. This solves the practical difficulty of quickly and accurately installing targets of different specifications (size, weight, shape) in the field.

[0055] The following is combined with Figures 1 to 4 The present invention describes the microwave remote sensing ground calibration target placement device and target placement method.

[0056] This invention provides a microwave remote sensing ground calibration target placement device, including a mounting frame 200, an azimuth calibration component 300, and an elevation calibration component 400. The azimuth calibration component 300 and the elevation calibration component 400 are both mounted on the mounting frame 200, which can simultaneously provide references for the azimuth and elevation angles of the target, thus solving the problem that after the first parameter is adjusted, the first parameter changes when the second parameter is adjusted, resulting in the first parameter changing after the first parameter is adjusted.

[0057] Mounting bracket 200 can be a longitudinal link, and azimuth calibration component 300 and pitch calibration component 400 can be set at different heights along the length of mounting bracket 200. The longitudinal link can be a telescopic rod, and the extension and retraction of the longitudinal link can adjust the ground clearance of azimuth calibration component 300 and pitch calibration component 400.

[0058] In one embodiment of the present invention, the longitudinal connecting rod can be a hollow metal rod with an outer diameter of 1 cm. The longitudinal connecting rod can be a three-section telescopic structure, with a length of 1 m when retracted and a length of 1.8 m when fully extended. The bottom end of the longitudinal connecting rod can be a pointed tip, which facilitates the insertion and fixing of the bottom end of the longitudinal connecting rod into the ground.

[0059] The azimuth calibration component 300 may include an azimuth measuring device 310 and a first reference component 320. The azimuth measuring device 310 includes a first scale 311, a north arrow 312, and an azimuth pointer 313. The first reference component 320 includes a first reference rod 321 and a connecting rod 322.

[0060] The first dial 311 is rotatably connected to the mounting bracket 200, and when the mounting bracket 200 is supported on the ground, the first dial 311 is parallel to the horizontal plane.

[0061] In one embodiment of the present invention, the first dial 311 can be a disc, and its upper surface has angular markings from 0 to 360 degrees. When the mounting bracket 200 is a longitudinal connecting rod, the longitudinal connecting rod passes through the center of the first dial 311, and the longitudinal connecting rod and the first dial 311 are coaxially arranged. To prevent the first dial 311 and the longitudinal connecting rod from rotating arbitrarily, a damping element can be provided between the first dial 311 and the longitudinal connecting rod. Under manual rotation, the first dial 311 can rotate around the longitudinal connecting rod, and when no external force is applied, the first dial 311 and the longitudinal connecting rod remain relatively stationary.

[0062] The compass 312 is rotatably connected to the longitudinal connecting rod. To allow the compass 312 and the longitudinal connecting rod to rotate freely, a bearing can be installed between the compass 312 and the longitudinal connecting rod. The purpose of the first dial 311 being rotatably connected to the mounting bracket 200 is to allow the first dial 311 to be rotated to the position where the 0-degree mark coincides with the compass 312 after the compass 312 stops rotating, thus making reading more convenient.

[0063] One end of the azimuth pointer 313 is rotatably connected to the mounting bracket 200, and the other end extends radially along the longitudinal connecting rod. Since the first dial 311 can be rotated to a position where the 0-degree mark coincides with the compass 312, the angle value corresponding to the angle mark pointed to by the azimuth pointer 313 is the azimuth angle.

[0064] In addition, to prevent the azimuth pointer 313 from rotating arbitrarily, a damping element can be installed between the azimuth pointer 313 and the longitudinal link. When the azimuth pointer 313 is moved, the azimuth pointer 313 can rotate around the longitudinal link. When there is no external force interference, the azimuth pointer 313 remains stationary.

[0065] In one embodiment of the present invention, the distal end of the azimuth pointer 313 extends to the outer side of the dial surface of the first scale 311. The distal end of the azimuth pointer 313 is connected to the top end of the connecting rod 322 of the first reference component 320. The first reference rod 321 of the first reference component 320 is connected to the bottom end of the connecting rod 322. The first reference rod 321 moves with the rotation of the azimuth pointer 313, and the projections of the first reference rod 321 and the azimuth pointer 313 on the first scale 311 are parallel or coincident. That is, when the azimuth pointer 313 is adjusted to an angle parallel to the designed route, the first reference rod 321 is parallel to the designed route.

[0066] The pitch angle measuring device 410 includes a second scale 411 and a pitch angle pointer 412, and the second reference component 420 includes a second reference rod 421.

[0067] The second dial 411 can be a disc. The second dial 411 is fixedly connected to the mounting bracket 200, and when the mounting bracket 200 is supported on the ground, the second dial 411 is perpendicular to the horizontal plane.

[0068] The surface of the second dial 411 has angle markings, including a 0-degree marking, which can extend horizontally, that is, the 0-degree marking is perpendicular to the longitudinal connecting rod, and includes 0 to 180-degree markings and 0 to -180-degree markings in the clockwise and counterclockwise directions, respectively.

[0069] The distal end of the pitch angle pointer 412 can be connected to the center of the second dial 411 by rotating a pivot, and the value of the angle scale pointed to by the pitch angle pointer 412 is the current pitch angle.

[0070] In addition, to prevent the pitch angle pointer 412 from rotating freely, a damping element can be installed between the rotating shaft and the second scale 411. When the pitch angle pointer 412 is manually rotated, the pitch angle pointer 412 can rotate. When the external force is lost, the pitch angle pointer 412 remains stationary relative to the second scale 411.

[0071] The second reference assembly 420 includes a second reference rod 421, one end of which is connected to the proximal end of the pitch angle pointer 421, and the other end of which extends in a direction away from the distal end of the pitch angle pointer 412, and the second reference rod 421 is located on the extension line of the pitch angle pointer 412.

[0072] In one embodiment of the present invention, in order to ensure that the first dial 311 is parallel to the horizontal plane when the mounting bracket 200 is supported on the ground, a level 500 can be set on the first dial 311. The level 500 can be a universal bubble level. When the bubble is located in the center, it indicates that the first dial 311 is parallel to the horizontal plane.

[0073] Of course, the level 500 can also be set on the second dial 411. When the second dial 411 is in a vertical state, the first dial 311 is also in a state parallel to the horizontal plane.

[0074] The target placement method provided by this invention addresses the problems of low accuracy, relatively complex operation, long time consumption, and low efficiency encountered in the installation of corner reflectors 100 during current microwave remote sensing ground calibration. It designs an integrated microwave remote sensing ground calibration target placement device. This device combines the required azimuth calibration component 300 and elevation calibration component 400 into a rigid connection through a longitudinal connecting rod. The azimuth calibration component 300 and elevation calibration component 400 are adjusted to the designed angles, completing the adjustment or calibration of the azimuth and elevation angles of the azimuth pointer 313 and elevation pointer 412. Then, the position status of the azimuth pointer 313 and elevation pointer 412 is transmitted to the corner reflector 100 through the first reference rod 321 and the second reference rod 421, assisting the corner reflector 100 installers in quickly completing the installation according to the design.

[0075] The microwave remote sensing ground calibration target placement device provided by this invention shifts the attitude adjustment process from directly affecting the corner reflector 100 to adjusting the attitude of the microwave remote sensing ground calibration target placement device itself. This device can be operated by a single person, and after rapid calibration, it can be fixed on the ground without requiring additional manpower. Technicians can then focus on installing the corner reflector 100 and adjusting its azimuth and elevation angles as needed. This avoids direct manipulation of the large and heavy corner reflector 100, transforming attitude adjustment into placement according to instructions. Throughout the process, the attitude of the microwave remote sensing ground calibration target placement device remains fixed, and the two angles can be cross-checked, ensuring that the attitude of the corner reflector 100 can be checked at any time during placement without the need for additional setup equipment. The entire placement process of the corner reflector 100 is efficient, simple, easy to use, and labor-saving.

[0076] The present invention also provides a target placement method, which mainly uses the microwave remote sensing ground calibration target placement device described above to place the target, and therefore also has the same advantages as described above.

[0077] The target placement method includes the following steps:

[0078] Step S100: Support the bottom of the mounting bracket 200 on the ground, so that the azimuth measuring device 310 is parallel to the horizontal plane and the pitch measuring device 410 is perpendicular to the horizontal plane.

[0079] Step S200: Adjust the azimuth pointer 313 so that the azimuth pointer 313 points parallel to the designed flight path of the aircraft.

[0080] Step S300: Adjust the pitch angle pointer 412 so that the pitch angle pointer 412 points parallel to the vertical line of the designed flight path, and the vertical line passes through the calibration point of the target.

[0081] Step S400: Install the target with reference to the positions of the first reference component 320 and the second reference component 420.

[0082] Specifically, during use, the microwave remote sensing ground calibration target placement device is fixed near the installation position of the corner reflector 100. The interval distance is determined by the size of the corner reflector 100. It is necessary to ensure that the bottom edge of the corner reflector 100 parallel to the designed flight path, that is, the azimuth reference line, can be in contact with the first reference rod 321 of the microwave remote sensing ground calibration target placement device, and that the elevation reference plane can be in contact with the second reference rod 421 of the microwave remote sensing ground calibration target placement device.

[0083] The mounting bracket 200 can be a longitudinal connecting rod with a pointed bottom, which can be directly inserted into the ground and fixed to the ground. After the mounting bracket 200 is fixed to the ground, the first scale 311 of the azimuth measuring device 310 can be determined by observing the level 500 to see if it is parallel to the horizontal plane. When the first scale 311 is parallel to the horizontal plane, the second scale 411 of the pitch measuring device 410 will naturally be perpendicular to the horizontal plane.

[0084] Once adjusted, observe the position of the compass 312 and rotate the first dial 311 until the 0-degree mark of the first dial 311 coincides with the position of the compass 312.

[0085] Then, based on the angle of the aircraft's designed flight path, the azimuth pointer 313 is rotated to an angle parallel to the designed flight path, and based on the perpendicular line between the calibration point and the designed flight path, the pitch pointer 412 is rotated to a position parallel to that perpendicular line.

[0086] Finally, the target is positioned according to the position of the first reference rod 321 and the second reference rod 421.

[0087] Furthermore, installing the target according to the positions of the first reference component 320 and the second reference component 420 includes the following steps:

[0088] Step S410: Adjust the target to a position where the azimuth reference line is parallel to the end of the first reference component 320 away from the azimuth pointer 313.

[0089] Step S420: Adjust the target to a position where the pitch angle reference plane is parallel to the second reference component 420.

[0090] Specifically, after the microwave remote sensing ground calibration target placement device is adjusted into place, the first reference rod 321 of the microwave remote sensing ground calibration target placement device is parallel to the designed flight path, and the second reference rod 421 of the microwave remote sensing ground calibration target placement device is parallel to the perpendicular line between the calibration point and the designed flight path.

[0091] Taking a triangular pyramid angle reflector as an example, the vertex of the triangular pyramid can be placed at the calibration point. By rotating the triangular pyramid, the top surface of the base plate of the triangular pyramid is made parallel to the edge line on the side of the opening with the first reference rod 321, and the azimuth angle of the corner reflector 100 is determined.

[0092] At this point, the second reference rod 421 is positioned above the top surface of the base plate of the corner reflector 100. Keeping the azimuth angle of the corner reflector 100 constant, rotate the triangular pyramid vertically, using the vertex as a fulcrum, until the edge of the base plate of the pyramid near the opening is raised upwards until the top surface of the base plate of the pyramid is completely in contact with the second reference rod 421. This completes the calibration of the pitch angle. Place a support below the triangular pyramid to fix it in this position.

[0093] Finally, check the positional relationship between the corner reflector 100 and the microwave remote sensing ground calibration target placement device. If there are changes in the azimuth or elevation angle, make fine adjustments according to the above steps. Finally, complete the calibration of the azimuth and elevation angles of the corner reflector 100, thereby realizing the rapid placement of the corner reflector 100.

[0094] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A microwave remote sensing ground calibration target placement device, characterized in that, include: Mounting bracket (200), the bottom end of which is used for support on the ground; An azimuth calibration component (300) includes an azimuth measuring device (310) and a first reference component (320). The azimuth measuring device (310) is mounted on the mounting frame (200). The first reference component (320) is connected to the azimuth pointer (313) of the azimuth measuring device (310). The first reference component (320) is used to provide a reference for the azimuth reference line (110) of the target. The pitch angle calibration component (400) includes a pitch angle measuring device (410) and a second reference component (420). The pitch angle measuring device (410) is mounted on the mounting frame (200). The second reference component (420) is connected to the pitch angle pointer (412) of the pitch angle measuring device (410). The second reference component (420) is used to provide a reference for the pitch angle reference surface (120) of the target.

2. The microwave remote sensing ground calibration target placement device according to claim 1, characterized in that, The azimuth measuring device (310) includes: The first dial (311) is rotatably connected to the mounting bracket (200), and when the mounting bracket (200) is supported on the ground, the first dial (311) is parallel to the horizontal plane; A compass (312) is rotatably connected to the mounting bracket (200); The proximal end of the azimuth pointer (313) is rotatably connected to the mounting bracket (200); The rotation axes of the compass (312) and the azimuth pointer (313) are both collinear with the rotation axis of the first dial (311).

3. The microwave remote sensing ground calibration target placement device according to claim 2, characterized in that, The first reference component (320) includes a first reference rod (321) and a connecting rod (322). The first reference rod (321) is connected to the distal end of the azimuth pointer (313) through the connecting rod (322). The first reference rod (321) is parallel to the azimuth pointer (313).

4. The microwave remote sensing ground calibration target placement device according to claim 3, characterized in that, The pitch angle measuring device (410) includes: The second dial (411) is fixedly connected to the mounting bracket (200), and when the mounting bracket (200) is supported on the ground, the second dial (411) is perpendicular to the horizontal plane; The distal end of the pitch angle pointer (412) is rotatably connected to the center of the second dial (411), and the axis of rotation is perpendicular to the second dial (411).

5. The microwave remote sensing ground calibration target placement device according to claim 4, characterized in that, The second reference component (420) includes a second reference rod (421) which is collinear with the pitch angle pointer (412), and one end of the second reference rod (421) is connected to the proximal end of the pitch angle pointer (412), while the other end of the second reference rod (421) extends in a direction away from the distal end of the pitch angle pointer (412).

6. The microwave remote sensing ground calibration target placement device according to any one of claims 1 to 5, characterized in that, The mounting bracket (200) is a telescopic rod.

7. The microwave remote sensing ground calibration target placement device according to claim 2, characterized in that, Damping elements are provided between the azimuth pointer (313), the first dial (311), and the pitch pointer (412) and the mounting bracket (200).

8. The microwave remote sensing ground calibration target placement device according to claim 4 or 5, characterized in that, A level (500) is provided on the first dial (311) and / or the second dial (411).

9. A target placement method, characterized in that, The microwave remote sensing ground calibration target placement device as described in any one of claims 1 to 8 is used to provide a reference for the placement of the target, and the target placement method includes the following steps: The bottom of the mounting bracket (200) is supported on the ground, so that the azimuth measuring device (310) is parallel to the horizontal plane and the pitch measuring device (410) is perpendicular to the horizontal plane. Adjust the azimuth pointer (313) so that the direction of the azimuth pointer (313) is parallel to the designed flight path of the aircraft; Adjust the pitch angle pointer (412) so that the pitch angle pointer (412) points parallel to the vertical line of the designed flight path, and the vertical line passes through the calibration point of the target; The target is installed with reference to the positions of the first reference component (320) and the second reference component (420).

10. The target placement method according to claim 9, characterized in that, Installing the target with reference to the positions of the first reference component (320) and the second reference component (420) includes the following steps: The target is adjusted to a position where the azimuth reference line (110) is parallel to the end of the first reference component (320) that is away from the azimuth pointer (313); The target is adjusted to a position where the pitch angle reference plane (120) is parallel to the second reference component (420).

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