In-medium passive calibrators and methods of calibration for radar see-through detection

Abstract

This invention relates to the field of radar testing technology, and provides a passive calibrator and calibration method for radar penetration detection within a medium. The passive calibrator includes: a calibration element, a connecting rod, and lifting rings. The calibration element is configured to be disposed inside the penetrating medium, and includes a mounting base and reflectors. Multiple reflectors are arranged circumferentially along the central axis of the mounting base, with one end of each reflector connected at the central axis, forming a reflecting surface between adjacent reflectors. Two calibration elements are provided, with both ends of the connecting rod connected to the two calibration elements respectively. Two lifting rings are provided, located at the ends of the two calibration elements furthest from the connecting rod. The passive calibrator for radar penetration detection within a medium provided by this invention avoids the influence of surface scattering on the calibration results, enabling omnidirectional acquisition of the radar signal reflected by the calibrator. It also verifies the internal penetration detection resolution of the radar detection system, achieving a combined function of calibration and radar resolution verification.

Description

Technical Field

[0001] This invention relates to the field of radar testing technology, and in particular to a passive calibrator and calibration method for radar penetration detection within a medium. Background Technology

[0002] Radar detection is widely used in atmospheric, oceanographic, and land-based detection. In radar detection operations, radar calibrators are typically used to calibrate the radar system's errors. In practical applications, the radar calibrator is stably positioned at a specific spatial coordinate, and its orientation is adjusted to maximize the reflection of radar signals from certain incident directions. When the radar moves relative to the calibrator until its beam angle covers the calibrator's area, and the connection between the radar and the calibrator meets certain geometric conditions, most of the energy of the electromagnetic waves incident on the calibrator will be backscattered back to the radar system and received by the radar system's receiving antenna.

[0003] For some special solid or liquid media, although radar waves experience losses during propagation within the medium, the electromagnetic signals transmitted through the radar waves and reflected back to the receiving antenna still retain a significant amount of energy. This allows radar detection systems of a certain frequency to perform penetrating detection of the internal structure of the medium. However, when performing penetrating detection on media such as mountain glaciers or polar glaciers, the azimuth angle of the line connecting the radar detection payload and the calibrator varies considerably. Furthermore, conventional passive calibrators have limited reflective azimuth angles. Combined with factors such as scattering signals from the medium surface, even with a calibrator placed on the glacier surface, accurate radar signal calibration becomes difficult to perform. Summary of the Invention

[0004] This invention provides a passive calibrator and calibration method for radar penetration detection, which solves the problem in the prior art that it is difficult to accurately calibrate radar in penetrating media.

[0005] To solve the above-mentioned technical problems, this application is implemented as follows:

[0006] In a first aspect, the present invention provides a passive calibrator for radar penetration detection, comprising: a calibrator configured to be disposed inside a penetrating medium, including a mounting base and a reflector, wherein multiple reflectors are provided, the multiple reflectors are arranged circumferentially along the central axis of the mounting base, and one end of each of the multiple reflectors is connected at the central axis, and a reflective surface is formed between two adjacent reflectors;

[0007] The connecting rod has two calibration components, and the two ends of the connecting rod are respectively connected to the two calibration components;

[0008] The lifting rings are provided in two, and the two lifting rings are respectively located at the ends of the two calibration members away from the connecting rod.

[0009] According to the present invention, a passive calibrator for radar penetration detection is provided in a medium, wherein the calibrator element, the connecting rod and the lifting ring constitute a calibrator unit, and the calibrator unit is provided with multiple sets;

[0010] The passive calibrator also includes: a traction rope;

[0011] The traction rope is provided with at least one, and the traction rope connects multiple calibrator units in sequence.

[0012] According to the present invention, a passive calibrator for radar penetration detection is provided, wherein a plurality of the reflectors are uniformly arranged circumferentially along the central axis of the mounting base.

[0013] According to the present invention, a passive calibrator for radar penetration detection is provided in a medium, wherein the reflector is any one of a rectangular plate, a triangular plate, or a quarter-circle arc plate.

[0014] According to the present invention, a passive calibrator for radar penetration detection is provided in which the length of the connecting rod has various specifications, and the length of the passive calibrator corresponding to the different specifications of the connecting rod is matched with the resolution of the radar.

[0015] According to the present invention, a passive calibrator for radar penetration detection is provided, wherein the mounting base is a circular structure and the mounting base is provided in various specifications, and the diameter of the mounting base is different for different specifications.

[0016] According to the present invention, a passive calibrator for radar penetration detection is provided, wherein the mounting base has a chamfer on the side opposite to the reflector.

[0017] According to the present invention, a passive calibrator for radar penetration detection is provided in a medium, wherein both ends of the connecting rod are provided with external threads, and both sides of the calibrator are provided with threaded holes, and the connecting rod is threadedly connected to the calibrator.

[0018] According to the present invention, a passive calibrator for radar penetration detection is provided in a medium, wherein the calibrator is an aluminum alloy component.

[0019] Secondly, the present invention provides a method for radar calibration using the passive calibrator described above, comprising:

[0020] Determine the location and depth of the probe hole for the medium to be tested, and construct the probe hole at the location;

[0021] Determine the scaler length and the number of scaler units, and assemble the determined number of scaler units into a passive scaler;

[0022] The passive calibrator was lowered along the borehole to the specified depth and then fixed using a suspension method.

[0023] The electromagnetic waves reflected by the passive calibrator are obtained to calibrate the error of the radar under test and verify its resolution.

[0024] The present invention provides a passive calibrator and calibration method for radar penetration detection within a medium. By configuring the calibrator inside the penetrating medium, the calibrator can reflect radar signals propagating within the medium, avoiding the influence of radar scattering signals generated on the medium surface on the calibration results. Furthermore, multiple reflectors are arranged circumferentially along the central axis of the mounting base to reflect radar waves circumferentially, enabling the radar signals reflected by the calibrator to be collected from all directions. By selecting a connecting rod that matches the radar resolution and assembling the connecting rod and two calibrators into a rigid assembly, the intra-medium penetration detection resolution of the radar detection system can be verified, achieving the integrated function of calibration and radar resolution verification. Attached Figure Description

[0025] 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.

[0026] Figure 1 This is a diagram illustrating the backscattering principle of a radar calibrator.

[0027] Figure 2 This is a schematic diagram of the calibrator unit provided by the present invention.

[0028] Figure 3 This is an installation diagram of the passive calibrator provided by the present invention.

[0029] Figure 4 This is a flowchart illustrating the method for radar calibration using the passive calibrator provided by the present invention.

[0030] Figure label:

[0031] 1. Calibrator unit; 11. Calibration component; 12. Connecting rod; 13. Lifting ring;

[0032] 111. Mounting base; 112. Reflector;

[0033] 2. Traction rope; 100. Probe hole. Detailed Implementation

[0034] 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.

[0035] In the description of the embodiments of the present invention, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the purpose of clarifying the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of the present invention. In addition, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0036] In the description of the embodiments of the present invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of the present invention according to the specific circumstances.

[0037] In embodiments of the present invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0038] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0039] The following is combined with Figures 1 to 4 The present invention provides a detailed description of the passive calibrator and calibration method for radar penetration detection provided by the embodiments of the present invention through specific implementations and application scenarios.

[0040] Firstly, such as Figure 2 As shown, this embodiment provides a passive calibrator for radar-guided detection, including: a calibrator 11, a connecting rod 12, and a lifting ring 13.

[0041] The calibration element 11 is configured to be located inside the penetrating medium and includes a mounting base 111 and a reflector 112. Multiple reflectors 112 are provided and are arranged circumferentially along the central axis of the mounting base 111. One end of each of the multiple reflectors 112 is connected at the central axis, and a reflective surface is formed between two adjacent reflectors 112.

[0042] Two calibration components 11 are provided, and the two ends of the connecting rod 12 are respectively connected to the two calibration components 11.

[0043] There are two lifting rings 13, which are respectively located at the ends of the two calibration members 11 away from the connecting rod 12.

[0044] Understandable Figure 1This diagram illustrates the backscattering principle of a passive calibrator. As shown, the passive calibrator reflects radar signals, which are then received by the radar receiving antenna. This allows for calibration of the radar detection system's measurement errors based on medium parameters and the geometric positions of the calibrator and the radar system. In radar penetration detection missions, the propagation speed and attenuation characteristics of electromagnetic waves propagating through different media vary depending on the dielectric and conductivity properties of those media. Therefore, radar calibration for different application scenarios requires placing the calibrator within the specific application environment. For applications involving glacier detection or similar penetrating media, the scattering signals from the glacier surface, surrounding mountains, and the ice-rock interface are strong. However, the electromagnetic scattering inside the glacier is less pronounced due to smaller local physical changes. Therefore, in this embodiment, the passive calibrator is placed inside the glacier. This eliminates the need to place the calibrator on the surface of the penetrating medium, ensuring that the calibrator's scattered signal does not mix with the surface scattering signal, thus guaranteeing the accuracy of radar detection calibration for penetrating media.

[0045] In this embodiment, the mounting base 111 provides a mounting support for multiple reflectors 112. Since the multiple reflectors 112 are arranged circumferentially along the central axis of the mounting base 111, one end of each reflector 112 is connected to the central axis, and the other end faces the outside of the mounting base 111 and is arranged circumferentially along the mounting base 111. A reflecting surface is formed between two adjacent reflectors 112, which is used to reflect the electromagnetic waves emitted by the detection radar. Because the reflecting surface is also arranged circumferentially along the central axis, the passive calibrator of this embodiment can reflect electromagnetic waves incident from multiple directions. That is, the calibrator can collect circumferentially incident electromagnetic waves from all directions and can respond to electromagnetic waves from all directions. For radar calibration in harsh environments like glaciers where penetrating media are harsh, the calibrator is placed in the probe hole 100 inside the glacier. Its circumferential reflection characteristic allows for multi-directional and multi-angle reflection of radar signals without adjusting the spatial position or other geometric parameters of the calibrator during calibration, reducing the difficulty of radar signal calibration and enhancing the convenience of radar calibration.

[0046] The calibrator in this embodiment contains two calibration elements 11 and a connecting rod 12. The two calibration elements 11 are located at both ends of the connecting rod 12. Compared to a single calibration element 11, two calibration elements 11 can provide more reflective surface within a certain length, thereby collecting more data points for calibration calculation, resulting in better calibration performance for radars of a certain length. Furthermore, since the connecting rod 12 is rigid during calibration testing, the length of the calibrator remains unchanged, allowing the calibrator to be used for radar resolution verification in this application scenario. By selecting the length of the connecting rod 12, the overall length of the calibrator is matched to the length corresponding to the radar resolution. By performing fine imaging of the calibrator using the acquired calibrator reflection signal, the radar's detection resolution index can be verified.

[0047] Since the passive calibrator is placed inside the penetrating medium, a probe hole 100 needs to be constructed inside the penetrating medium before calibration testing, and the calibrator is placed inside the probe hole 100. In this embodiment, a lifting ring 13 is provided at one end of the calibrator 11 for hoisting the calibrator into the probe hole 100.

[0048] The passive calibrator for radar penetration detection provided by this invention, by configuring the calibrator 11 inside the penetrating medium, allows the calibrator to reflect radar signals propagating within the medium, thus avoiding the influence of radar scattering signals generated on the medium surface on the calibration results. Furthermore, multiple reflectors 112 are arranged circumferentially along the central axis of the mounting base 111 to reflect radar waves circumferentially, enabling the radar signals reflected by the calibrator to be collected from all directions. By selecting a connecting rod 12 that matches the radar resolution and assembling the connecting rod 12 and the two calibrators 11 into a rigid assembly, the intra-medium penetration detection resolution of the radar detection system can be verified, achieving the integrated function of calibration and verification of radar resolution.

[0049] like Figure 2 and Figure 3 As shown, in this embodiment, the calibrator unit 1 is composed of the calibrator component 11, the connecting rod 12 and the lifting ring 13, and the calibrator unit 1 is provided with multiple sets.

[0050] The passive calibrator also includes: a traction rope 2; the traction rope 2 is provided with at least one, and the traction rope 2 connects multiple calibrator units 1 in sequence.

[0051] Understandably, a calibrator unit 1 includes a connecting rod 12 and two calibrating elements 11 located at both ends of the connecting rod 12. Adjacent calibrator units 1 are connected by a traction rope 2, which is mounted on a lifting ring 13, facilitating the rapid connection of multiple calibrator units 1 on site.

[0052] Specifically, one traction rope 2 is provided, and two calibrator units 1 are connected to the two ends of the traction rope 2. Multiple traction ropes 2 are provided, and the multiple traction ropes 2 are connected to different calibrator units 1 respectively. The multiple calibrator units 1 are connected in sequence to form a longer calibrator.

[0053] like Figure 3 As shown, L1 is the length of one calibrator unit 1, L2 is the distance between the same positions of two sets of calibrator units 1, and L2-L1 is the length of the traction rope 2. D2 is the diameter of the calibrator component, and D1 is the diameter of the probe hole.

[0054] When constructing a borehole 100 inside a glacier or ice layer, the dielectric constant and conductivity of the ice layer change at different depths, resulting in different calibration parameters for the radar at different depths. Therefore, it is necessary to place multiple calibrator units 1 at different depths to collect data on electromagnetic wave reflections. Thus, this embodiment uses multiple sets of calibrator units 1 to form a passive calibrator. Multiple sets of calibrator units 1 independently reflect and collect electromagnetic waves emitted by the radar at different depths, obtaining different calibration parameters, which can improve the calibration capability of the calibrator.

[0055] like Figure 1 As shown, in this embodiment, multiple reflectors 112 are evenly arranged circumferentially along the central axis of the mounting base 111.

[0056] Understandably, the circumferentially uniform arrangement of multiple reflectors 112 ensures that the reflective surfaces along the central axis of the mounting base 111 are also circumferentially uniform, forming a three-dimensional, uniform reflective surface over a 360° range. This allows for the equidistant reflection of the radar's electromagnetic waves, providing consistent reflection performance in all directions, improving the omnidirectional signal of the reflected electromagnetic waves, and avoiding target identification errors caused by the radar cross-section. Furthermore, the circumferentially uniform arrangement allows for the reuse of the same reflectors 112, reducing design complexity and facilitating mass production and assembly.

[0057] Specifically, in this embodiment, there are four reflectors 112, and the included angle between the four reflectors 112 is 90°.

[0058] like Figure 2 As shown, the reflector 112 in this embodiment is any one of a rectangular plate, a triangular plate, or a quarter-circle arc plate.

[0059] Understandably, when the reflector 112 is a rectangular plate, one wide side of the rectangular plate is connected at the central axis of the mounting base 111, and the other wide side extends outward toward the mounting base 111 to form a rectangular reflective surface.

[0060] Alternatively, when the reflector 112 is a triangular plate, one right-angled side of the triangular plate is connected at the central axis of the mounting base 111, and the other right-angled side extends outward toward the mounting base 111 to form a triangular reflective surface.

[0061] Alternatively, when the reflector 112 is a quarter-circular arc plate, one straight edge of the arc plate is connected at the central axis of the mounting base 111, and the other straight edge extends outward toward the mounting base 111 to form an arc-shaped reflective surface.

[0062] like Figure 2 As shown, the length of the connecting rod 12 in this embodiment has various specifications, and the length of the passive calibrator corresponding to the connecting rod 12 of different specifications is matched with the resolution of the radar.

[0063] It is understandable that the resolution of a radar varies depending on the detection radar or the operating mode of the same radar. To ensure that the length of the passive calibrator matches the radar resolution, the length of the connecting rod 12 in this embodiment has various specifications, with different lengths for different specifications, so that the length of the assembled calibrator is consistent with the specific resolution of the radar.

[0064] When testing the signal errors of different detection radars or different operating modes of the same radar, calibrators can be assembled using connecting rods 12 of different lengths. The calibrator component 11 can be manufactured as a standard part; by selecting connecting rods 12 of different specifications for assembly, calibrators corresponding to different resolutions can be obtained. In practical applications, the specifications of the connecting rods 12 can be flexibly selected according to the site conditions without the need for on-site temporary processing, thus improving the efficiency of calibrator assembly and increasing the calibrator's versatility.

[0065] like Figure 2 and Figure 3 As shown, the mounting base 111 in this embodiment has a circular structure. The mounting base 111 has various specifications, and the diameter of the mounting base 111 of different specifications is different.

[0066] Understandably, the diameter of the mounting base 111 needs to be smaller than the diameter of the borehole 100. To ensure the proper mounting posture of the mounting base 111 within the borehole 100, the diameter of the mounting base 111 and the diameter of the borehole 100 cannot differ too much. To accommodate different borehole 100 sizes, the mounting base 111 is available in various specifications, with different sizes of borehole 100 corresponding to different specifications of mounting base 111. During field operations, a mounting base 111 with a diameter smaller than but not significantly different from the borehole 100's diameter is selected based on the borehole 100's diameter. The mounting base 111 can be lowered from the top of the borehole 100 into the glacier using a traction rope 2.

[0067] This embodiment allows for flexible selection of mounting bases 111 of different specifications based on the size of the probe hole 100 on site, eliminating the need for on-site processing of the mounting bases 111 and thus improving on-site installation efficiency.

[0068] like Figure 2 As shown, the mounting base 111 in this embodiment has a chamfer on the side facing away from the reflector 112.

[0069] It is understandable that when the mounting base 111 is lowered from the probe hole 100, the end of the mounting base 111 facing the bottom of the probe hole 100 is chamfered, which can facilitate the lowering process of the mounting base 111 and prevent the mounting base 111 from being pulled by the inner wall of the probe hole 100, thus affecting the arrival of the correct placement position of the calibrator.

[0070] like Figure 2 As shown, both ends of the connecting rod 12 in this embodiment are provided with external threads, and the calibration component 11 is provided with threaded holes on both sides. The connecting rod 12 is threadedly connected to the calibration component 11.

[0071] Understandably, since connecting rod 12 and calibration component 11 can be assembled on-site, and the two ends of connecting rod 12 and calibration component 11 are connected by threads, rapid assembly and disassembly are possible. Furthermore, since connecting rod 12 and calibration component 11 come in different specifications, appropriate connecting rod 12 and calibration component 11 can be selected on-site based on the size of the borehole 100 and the radar resolution, and rapid assembly is achieved through threaded connections, improving on-site assembly efficiency and enabling the connection of connecting rods 12 and calibration components 11 of different specifications.

[0072] like Figure 2 As shown, the calibration component 11 in this embodiment is a machined part made of a material that can effectively reflect radar waves. Specifically, the calibration component 11 is an aluminum alloy part.

[0073] Secondly, such as Figure 4 As shown, this embodiment provides a method for radar calibration using the passive calibrator described above, including the following steps:

[0074] Step 411: Determine the location and depth of the probe hole for the penetrating medium to be tested, and construct the probe hole 100 at the probe hole location.

[0075] It is understood that the penetrating medium in this embodiment includes a variety of media capable of penetrating electromagnetic waves emitted by radar, with glaciers as an example for illustration.

[0076] After measuring and analyzing data from the glacier, the location of the probe hole 100 to be tested in the penetrating medium is determined, as are its depth and diameter. The probe hole 100 is then drilled along the depth direction of the glacier using drilling equipment. In this embodiment, the radar calibration method involves placing a calibration element 11 inside the penetrating medium, causing the calibration element 11 to reflect electromagnetic waves within the medium, thus avoiding the scattering effect from the glacier surface and improving calibration accuracy. Furthermore, drilling can be completed at a suitable location, avoiding prolonged work in the harsh environment at the top of the glacier and enhancing the operational experience for the experimental personnel.

[0077] Step 412: Determine the calibrator length and the number of calibrator units 1, and assemble the determined number of calibrator units 1 into a passive calibrator.

[0078] Understandably, the number and placement interval of calibrators are selected based on the determined depth of the borehole 100. For example, one calibrator is placed at certain depths. Furthermore, the number of calibrator units 1 within each calibrator is determined, and the appropriate specifications of the connecting rod 12 are selected based on the resolution of the detection radar, as well as the appropriate mounting base 111 is selected based on the diameter of the borehole 100. The calibrator units 11 and connecting rods 12 are then assembled into a calibrator unit 1. Multiple calibrator units 1 are sequentially connected using a traction rope 2 to form a calibrator.

[0079] Step 413: Use a suspension method to lower the passive calibrator along the probe hole 100 to the specified depth and fix it.

[0080] Understandably, a winch is used to place the calibrator into the preset position within the probe hole 100 to complete the installation of the passive calibrator.

[0081] Step 414: Obtain the electromagnetic wave reflected by the passive calibrator, calibrate the error of the radar under test, and verify the resolution of the radar under test.

[0082] Understandably, to conduct a calibration test of the passive calibrator, the radar is activated to emit electromagnetic waves, and the electromagnetic waves reflected by the passive calibrator are obtained circumferentially along the depth direction of the probe hole 100 to calibrate the signal error of the radar under test.

[0083] At the same time, based on the signals transmitted and received by the radar under test, the echoes of the two calibration components 11 of the passive calibrator are recorded, and fine imaging of the calibration components 11 is performed to verify the resolution performance of the radar under test.

[0084] 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 passive calibrator in a medium for radar see-through detection, characterized in that, include: At least one calibrator unit includes two calibrators, a connecting rod, and two lifting rings. Each calibrator is configured to be disposed within a penetrating medium, including a mounting base and a reflector, the medium being a glacier. Multiple reflectors are arranged circumferentially along the central axis of the mounting base, with one end of each reflector connected at the central axis, forming a reflective surface between adjacent reflectors. The connecting rod is connected to two calibrators at both ends, and the connecting rod has various lengths, with different lengths corresponding to passive calibrators whose resolution matches that of the radar under test. The two lifting rings are located at the ends of the two calibrators furthest from the connecting rod. A traction rope, wherein there is at least one traction rope, for connecting multiple calibrator units sequentially; The reflector is any one of a rectangular plate, a triangular plate, or a quarter-circle plate; the diameter of the mounting base is smaller than the diameter of the probe hole in the medium. During the calibration test, a probe hole is first constructed inside the penetrating medium, and the calibrator is placed inside the probe hole. A lifting ring is provided at one end of the calibrator to suspend the calibrator into the probe hole. The passive calibrator is lowered along the probe hole to a specified depth and fixed using a suspension method.

2. The passive calibrator for radar penetration detection according to claim 1, characterized in that, The mounting base has a circular structure and comes in various sizes, with different diameters for each size.

3. The passive calibrator for radar penetration detection according to claim 2, characterized in that, The mounting base has a chamfer on the side opposite to the reflector.

4. The passive calibrator for radar penetration detection according to claim 1, characterized in that, Both ends of the connecting rod are provided with external threads, and the calibration component is provided with threaded holes on both sides. The connecting rod is threadedly connected to the calibration component.

5. The passive calibrator for radar penetration detection according to claim 1, characterized in that, The calibration component is an aluminum alloy component.

6. A method for radar calibration using the passive calibrator according to any one of claims 1 to 5, characterized in that, include: Determine the location and depth of the probe hole for the medium to be tested, and construct the probe hole at the location; Determine the scaler length and the number of scaler units, and assemble the determined number of scaler units into a passive scaler; The passive calibrator was lowered along the borehole to the specified depth and then fixed using a suspension method. The electromagnetic waves reflected by the passive calibrator are obtained to calibrate the error of the radar under test and verify its resolution.

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