Real-time spectrum-based ground penetrating radar loss tangent estimation method

Abstract

The disclosure provides a real-time spectrum-based ground penetrating radar loss tangent estimation method. The real-time spectrum-based ground penetrating radar loss tangent estimation method comprises: obtaining a ground surface echo signal corresponding to a profile data graph based on the profile data graph obtained based on radar observation; calculating the incident signal spectrum of the radar, and obtaining a theoretical relationship curve of the change of the center frequency with time according to the incident signal spectrum and the wave equation satisfied by the transmission of electromagnetic waves in the medium, taking the theoretical relationship curve of the change of the center frequency with time as a theoretical center frequency decay curve; performing time-frequency analysis based on the profile data graph to analyze the instantaneous spectrum matrix of the radar signal in the detection process, and calculating a measured curve of the change of the center frequency with time according to the instantaneous spectrum matrix, taking the measured curve of the change of the center frequency with time as a measured center frequency decay curve; and determining the ground penetrating radar loss tangent estimation result.

Description

Technical Field

[0001] This disclosure relates to the field of planetary exploration technology, and more specifically to a method, apparatus, electronic device, and storage medium for estimating the loss tangent of a ground-penetrating radar based on real-time spectrum. Background Technology

[0002] Planetary subsurface penetrating radar (PSDR) is a widely used detection technology in planetary exploration. PSDR emits electromagnetic pulses towards targets such as the Moon and Mars, and collects the echo signals to infer the electromagnetic properties of regions below the planet's surface. The loss tangent parameter reflects the electromagnetic loss of the medium, i.e., the attenuation rate of electromagnetic waves as they penetrate the medium; a larger loss tangent indicates faster attenuation. This parameter is related to the content of iron oxide and titanium dioxide in the medium, providing clues for determining the formation history of corresponding regions and analyzing their mineral reserves.

[0003] The traditional method for estimating the loss tangent is the frequency offset method. This method requires assuming the radar signal is a known Gaussian pulse or Ricker wavelet, calculating the attenuation rate of the radar signal's center frequency over time, and then using this to infer the medium's loss tangent. Therefore, if the radar signal transmitted does not match the assumptions, the estimation results will exhibit systematic bias, leading to errors in subsequent radar signal interpretation. Summary of the Invention

[0004] In view of the above problems, this disclosure provides a method, apparatus, device and medium for estimating the loss tangent of ground penetrating radar based on real-time spectrum.

[0005] According to a first aspect of this disclosure, a method for estimating the loss tangent of a ground-penetrating radar (GPR) based on real-time spectrum is provided, comprising: identifying an initial echo signal based on a profile data map obtained from radar observations to identify a surface echo signal corresponding to the profile data map; calculating the incident signal spectrum of the radar based on the surface echo signal, and obtaining a theoretical relationship curve of the center frequency changing with time based on the incident signal spectrum and the wave equation satisfied by electromagnetic waves propagating in a medium, and using the theoretical relationship curve of the center frequency changing with time as a theoretical center frequency attenuation curve; performing time-frequency analysis based on the profile data map to analyze and obtain the instantaneous spectrum matrix of the radar signal during the detection process, and calculating a measured curve of the center frequency changing with time based on the instantaneous spectrum matrix, and using the measured curve of the center frequency changing with time as a measured center frequency attenuation curve; and determining the GPR loss tangent estimation result based on the theoretical center frequency attenuation curve and the measured center frequency attenuation curve.

[0006] According to embodiments of this disclosure, the step of calculating the incident signal spectrum of the radar based on the surface echo signal, and obtaining a theoretical relationship curve of the center frequency changing with time based on the incident signal spectrum and the wave equation satisfied by the electromagnetic wave propagation in the medium, and using the theoretical relationship curve of the center frequency changing with time as the theoretical center frequency attenuation curve, includes: calculating the incident signal spectrum of the radar based on the surface echo signal using a windowed Fourier transform; and establishing a theoretical relationship of the center frequency changing with time of the incident signal under a medium with an assumed loss tangent value, based on the wave equation satisfied by the electromagnetic wave propagation in the medium, to obtain the theoretical relationship curve of the center frequency changing with time.

[0007] According to embodiments of this disclosure, time-frequency analysis is performed based on the profile data map to obtain the instantaneous spectrum matrix of the radar signal during the detection process. This includes: using a short-time Fourier transform method or an S-transform method to perform time-frequency analysis based on the profile data map to obtain the instantaneous spectrum matrix of the radar signal during the detection process.

[0008] According to an embodiment of this disclosure, determining the ground-penetrating radar loss tangent estimation result based on the theoretical center frequency attenuation curve and the measured center frequency attenuation curve includes: obtaining the ground-penetrating radar loss tangent estimation result using the least squares method based on the theoretical center frequency attenuation curve and the measured center frequency attenuation curve.

[0009] The second aspect of this disclosure provides a ground-penetrating radar loss tangent estimation device based on real-time spectrum, comprising: a first acquisition module, configured to identify an initial echo signal based on a profile data map obtained from radar observation, to identify a surface echo signal corresponding to the profile data map; a second acquisition module, configured to calculate the incident signal spectrum of the radar based on the surface echo signal, and obtain a theoretical relationship curve of the center frequency changing with time based on the incident signal spectrum and the wave equation satisfied by electromagnetic waves propagating in a medium, and use the theoretical relationship curve of the center frequency changing with time as a theoretical center frequency attenuation curve; a third acquisition module, configured to perform time-frequency analysis based on the profile data map, to analyze and obtain the instantaneous spectrum matrix of the radar signal during the detection process, and calculate a measured curve of the center frequency changing with time based on the instantaneous spectrum matrix, and use the measured curve of the center frequency changing with time as a measured center frequency attenuation curve; and a determination module, configured to determine the ground-penetrating radar loss tangent estimation result based on the theoretical center frequency attenuation curve and the measured center frequency attenuation curve.

[0010] A third aspect of this disclosure provides an electronic device comprising: one or more processors; and a memory for storing one or more programs, wherein, when the one or more programs are executed by the one or more processors, the one or more processors perform the methods disclosed above.

[0011] A fourth aspect of this disclosure also provides a computer-readable storage medium having executable instructions stored thereon, which, when executed by a processor, cause the processor to perform the methods disclosed above. Attached Figure Description

[0012] The foregoing contents, as well as other objects, features, and advantages of this disclosure, will become clearer from the following description of embodiments with reference to the accompanying drawings, in which:

[0013] Figure 1 A flowchart illustrating a ground-penetrating radar loss tangent estimation method based on real-time spectrum according to an embodiment of the present disclosure is shown.

[0014] Figure 2 A schematic diagram illustrating the calculation of the instantaneous spectrum using the S-transform is shown.

[0015] Figure 3 The diagram illustrates the estimation of the loss tangent by fitting the theoretical relationship and the measured center frequency over time.

[0016] Figure 4 A schematic diagram illustrates the structure of a ground-penetrating radar loss tangent estimation device based on real-time spectrum according to an embodiment of the present disclosure; and

[0017] Figure 5 A block diagram of an electronic device suitable for implementing a ground-penetrating radar loss tangent estimation method based on real-time spectrum, according to embodiments of the present disclosure, is illustrated. Detailed Implementation

[0018] The embodiments of the present disclosure will now be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the disclosure. In the following detailed description, numerous specific details are set forth to provide a thorough understanding of the embodiments of the present disclosure for ease of explanation. However, it will be apparent that one or more embodiments may be practiced without these specific details. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concepts of the present disclosure.

[0019] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. The terms “comprising,” “including,” etc., as used herein indicate the presence of the stated features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0020] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein are to be interpreted in a manner consistent with the context of this specification, and not in an idealized or overly rigid way.

[0021] When using expressions such as "at least one of A, B, and C", they should generally be interpreted in accordance with the meaning that is commonly understood by a person skilled in the art (e.g., "a system having at least one of A, B, and C" should include, but is not limited to, a system having A alone, a system having B alone, a system having C alone, a system having A and B, a system having A and C, a system having B and C, and / or a system having A, B, and C, etc.).

[0022] The embodiments of this disclosure provide a method and apparatus for estimating the loss tangent of ground-penetrating radar based on real-time spectrum. The method involves: identifying initial echo signals based on profile data obtained from radar observations to identify surface echo signals corresponding to the profile data; calculating the incident signal spectrum of the radar based on the surface echo signals; obtaining a theoretical relationship curve of the center frequency versus time based on the incident signal spectrum and the wave equation satisfied by electromagnetic waves propagating in a medium; using this theoretical relationship curve as the theoretical center frequency attenuation curve; performing time-frequency analysis based on the profile data to obtain the instantaneous spectrum matrix of the radar signal during the detection process; calculating a measured curve of the center frequency versus time based on the instantaneous spectrum matrix; using this measured curve as the measured center frequency attenuation curve; and determining the ground-penetrating radar loss tangent estimation result based on the theoretical and measured center frequency attenuation curves.

[0023] Based on the principle that the electromagnetic wave signal of planetary subsurface penetrating radar attenuates in the medium, causing the center frequency to decrease, the dielectric loss tangent parameter at any radar detection position is determined by initial echo identification, time-frequency analysis, and optimization methods.

[0024] pass Figure 1 The loss tangent estimation method of ground penetrating radar based on real-time spectrum according to the embodiments of this disclosure will be described in detail.

[0025] Figure 1 A flowchart illustrating a ground-penetrating radar loss tangent estimation method based on real-time spectrum according to an embodiment of this disclosure is shown. Figure 1 As shown, this embodiment includes operations S101 to S104.

[0026] In operation S101, initial echo signal identification is performed based on the profile data map obtained from radar observation, so as to identify the surface echo signal corresponding to the profile data map.

[0027] It is understandable that initial echo signal identification based on the profile data obtained from radar observations can identify and extract the surface echoes within it.

[0028] In operation S102, the incident signal spectrum of the radar is calculated based on the surface echo signal. Based on the incident signal spectrum and the wave equation satisfied by the electromagnetic wave in the medium, the theoretical relationship curve of the center frequency changing with time is obtained. The theoretical relationship curve of the center frequency changing with time is used as the theoretical center frequency attenuation curve.

[0029] In some embodiments, the incident signal spectrum of the radar can be calculated from the ground echo signal using a windowed Fourier transform. Then, based on the incident signal spectrum, a theoretical relationship between the center frequency of the incident signal and time is established in a medium with an assumed loss tangent, according to the wave equation satisfied by electromagnetic waves propagating in a medium, so as to obtain the theoretical relationship curve of the center frequency changing with time.

[0030] It can be understood that the incident signal spectrum is the real-time incident signal spectrum of the radar.

[0031] In operation S103, time-frequency analysis is performed based on the profile data map to obtain the instantaneous spectrum matrix of the radar signal during the detection process. The measured curve of the center frequency changing with time is calculated based on the instantaneous spectrum matrix and used as the measured center frequency attenuation curve.

[0032] In some embodiments, a short-time Fourier transform or an S-transform method can be used to perform time-frequency analysis based on the profile data map in order to obtain the instantaneous spectrum matrix of the radar signal during the detection process.

[0033] In operation S104, the loss tangent estimation result of ground penetrating radar is determined based on the theoretical center frequency attenuation curve and the measured center frequency attenuation curve.

[0034] In some embodiments, the ground-penetrating radar loss tangent estimation result can be obtained using the least squares method based on the theoretical center frequency attenuation curve and the measured center frequency attenuation curve.

[0035] The real-time spectrum-based ground-penetrating radar loss tangent estimation method of this disclosure does not require assuming the radar transmission waveform as in the traditional frequency offset method. Instead, it can be applied to ground-penetrating radars of any signal system to obtain an unbiased loss tangent estimate of the underground medium detected by the radar. This significantly improves the applicability of the frequency offset method and the accuracy of loss tangent estimation, which is of great significance for subsequent radar signal processing and interpretation.

[0036] The real-time spectrum-based ground-penetrating radar loss tangent estimation method of this disclosure can accurately estimate the dielectric loss tangent based on the principle of real-time spectrum center frequency shift of planetary subsurface penetrating radar signals. Furthermore, according to the real-time spectrum-based ground-penetrating radar loss tangent estimation method of this disclosure, the loss tangent parameters of the detected lunar and Martian subsurface components can be accurately estimated using planetary subsurface penetrating radar detection data.

[0037] For example, based on the location of the ground reflected wave in the radar profile, the instantaneous spectrum of the real-time initial signal can be calculated; for the radar measured echo signal, the curve of its center frequency change over time can be analyzed through time-frequency analysis; using the instantaneous spectrum of the real-time initial signal and the measured curve of the center frequency change, combined with the physical model of the center frequency offset, parameter estimation can be performed using optimizers such as least squares and Adam to obtain the loss tangent information of any layer in the radar profile at any travel distance.

[0038] It is understandable that using the radar signal spectrum obtained through real-time estimation as a benchmark eliminates the need to make any assumptions about the spectrum of the radar transmitted signal, making it applicable to a wider range of radar signal systems.

[0039] To better understand the ground-penetrating radar loss tangent estimation method based on real-time spectrum of the present invention, the following embodiments further illustrate the content of the ground-penetrating radar loss tangent estimation method based on real-time spectrum, but the present invention is not limited to the following embodiments.

[0040] Taking a set of measured radar profile data from the high-frequency channel of the lunar penetrating radar aboard Chang'e-4 as an example, the estimation of the loss tangent of the subsurface using this measured radar profile data involves six steps, which are implemented sequentially as follows:

[0041] Step 1 involves identifying and extracting surface echoes from the radar profile data. From the radar profile, reflected waves generated when electromagnetic waves pass through the vacuum-surface (lunar) interface can usually be distinguished. These reflected waves are typically the strongest and most stable signals obtainable by ground-penetrating radar and can be used as a reference for the radar's real-time transmission signal. The purpose of this step is to define the range of surface echoes to facilitate the subsequent calculation of the radar's real-time incident signal spectrum.

[0042] Step 2 involves using a windowed Fourier transform on the surface echo signal to calculate the real-time incident signal spectrum of the radar. This incident signal spectrum will later be used to calculate the theoretical relationship between its center frequency attenuation and loss tangent. i (t, tanδ). During calculation, the radar signal is windowed according to the surface echo interval, commonly using Gaussian windows or Kaiser windows, and then the Fourier transform is used to calculate the spectrum F of the incident signal. i (ω).

[0043] Step 3 involves calculating the theoretical relationship between the signal center frequency and time decay under the influence of the loss tangent using the incident spectrum. After establishing this relationship, the theoretical relationship can be fitted to the measured data using an optimization method to obtain the corresponding subsurface dielectric loss tangent parameters. In implementation, the spectrum F of the output incident signal described in step 2 is... i (ω), based on the wave equation satisfied by electromagnetic waves propagating in a medium, a theoretical relationship f is established for the change of the center frequency of an incident signal with time in a medium with an assumed loss tangent of tanδ. i (t, tanδ), where the relation satisfies:

[0044]

[0045] Step 4 involves calculating the change of the measured signal spectrum over time. The instantaneous spectrum must be calculated first, followed by the calculation of the center frequency's change over time. In practice, for the measured radar signal matrix, time-frequency analysis methods such as short-time Fourier transform or S-transform can be used to obtain the instantaneous spectrum matrix S of the radar signal during the corresponding detection process. i (t,ω), such as Figure 2 As shown.

[0046] Step 5 involves calculating the measured curve of the radar signal's center frequency changing over time using the instantaneous spectrum matrix. In practice, the instantaneous spectrum matrix obtained in Step 4 is used to calculate the measured curve of its center frequency changing over time. The corresponding mathematical expression is:

[0047]

[0048] Step 6 involves adjusting the loss tangent parameter using an optimization method, fitting the measured center frequency versus time curve with the theoretical relationship, thereby estimating the loss tangent parameter that best reflects the actual situation. In implementation, this is combined with the theoretical relationship f of the center frequency versus time calculated in Step 3. i (t, tanδ) and the measured curves of the center frequency versus time obtained in step 5. The optimal tanδ is obtained using optimization methods, such that f i (t,tanδ) and The values ​​are most consistent, and at this point, tanδ is the estimated loss tangent, such as... Figure 3 As shown.

[0049] Figure 4 A schematic block diagram of a ground-penetrating radar loss tangent estimation device based on real-time spectrum according to an embodiment of the present disclosure is shown.

[0050] like Figure 4 As shown, the ground-penetrating radar loss tangent estimation device 400 based on real-time spectrum in this embodiment includes a first acquisition module 410, a second acquisition module 420, a third acquisition module 430, and a determination module 440.

[0051] The first acquisition module 410 is used to identify the initial echo signal based on the profile data map obtained by radar observation, so as to identify the surface echo signal corresponding to the profile data map; the second acquisition module 420 is used to calculate the incident signal spectrum of the radar based on the surface echo signal, and obtain the theoretical relationship curve of the center frequency changing with time based on the incident signal spectrum and the wave equation satisfied by the electromagnetic wave in the medium, and use the theoretical relationship curve of the center frequency changing with time as the theoretical center frequency attenuation curve; the third acquisition module 430 is used to perform time-frequency analysis based on the profile data map, so as to analyze and obtain the instantaneous spectrum matrix of the radar signal during the detection process, and calculate the measured curve of the center frequency changing with time based on the instantaneous spectrum matrix, and use the measured curve of the center frequency changing with time as the measured center frequency attenuation curve; and the determination module 440 is used to determine the ground penetrating radar loss tangent estimation result based on the theoretical center frequency attenuation curve and the measured center frequency attenuation curve.

[0052] According to embodiments of this disclosure, any plurality of modules among the first obtaining module 410, the second obtaining module 420, the third obtaining module 430, and the determining module 440 may be combined into one module, or any one of these modules may be split into multiple modules. Alternatively, at least part of the functionality of one or more of these modules may be combined with at least part of the functionality of other modules and implemented in one module. According to embodiments of this disclosure, at least one of the first obtaining module 410, the second obtaining module 420, the third obtaining module 430, and the determining module 440 may be at least partially implemented as hardware circuitry, such as a field-programmable gate array (FPGA), a programmable logic array (PLA), a system-on-a-chip, a system-on-a-substrate, a system-on-package, an application-specific integrated circuit (ASIC), or implemented in hardware or firmware by any other reasonable means of integrating or packaging the circuitry, or implemented in any one of the three implementation methods of software, hardware, and firmware, or in a suitable combination of any of these. Alternatively, at least one of the first obtaining module 410, the second obtaining module 420, the third obtaining module 430, and the determining module 440 may be implemented at least partially as a computer program module, which can perform corresponding functions when the computer program module is run.

[0053] Figure 5 A block diagram of an electronic device suitable for implementing a ground-penetrating radar loss tangent estimation method based on real-time spectrum, according to embodiments of the present disclosure, is illustrated.

[0054] like Figure 5 As shown, an electronic device 500 according to an embodiment of the present disclosure includes a processor 501, which can perform various appropriate actions and processes according to a program stored in a read-only memory (ROM) 502 or a program loaded from a storage portion 508 into a random access memory (RAM) 503. The processor 501 may include, for example, a general-purpose microprocessor (e.g., a CPU), an instruction set processor and / or an associated chipset and / or a special-purpose microprocessor (e.g., an application-specific integrated circuit (ASIC)), etc. The processor 501 may also include onboard memory for caching purposes. The processor 501 may include a single processing unit or multiple processing units for performing different actions of the method flow according to an embodiment of the present disclosure.

[0055] RAM 503 stores various programs and data required for the operation of electronic device 500. Processor 501, ROM 502, and RAM 503 are interconnected via bus 504. Processor 501 performs various operations of the method flow according to embodiments of the present disclosure by executing programs in ROM 502 and / or RAM 503. It should be noted that the programs may also be stored in one or more memories other than ROM 502 and RAM 503. Processor 501 may also perform various operations of the method flow according to embodiments of the present disclosure by executing programs stored in said one or more memories.

[0056] According to embodiments of this disclosure, the electronic device 500 may further include an input / output (I / O) interface 505, which is also connected to a bus 504. The electronic device 500 may also include one or more of the following components connected to the I / O interface 505: an input section 506 including a keyboard, mouse, etc.; an output section 507 including a cathode ray tube (CRT), liquid crystal display (LCD), etc., and a speaker, etc.; a storage section 508 including a hard disk, etc.; and a communication section 509 including a network interface card such as a LAN card, modem, etc. The communication section 509 performs communication processing via a network such as the Internet. A drive 510 is also connected to the I / O interface 505 as needed. A removable medium 511, such as a disk, optical disk, magneto-optical disk, semiconductor memory, etc., is installed on the drive 510 as needed so that computer programs read from it can be installed into the storage section 508 as needed.

[0057] This disclosure also provides a computer-readable storage medium, which may be included in the device / apparatus / system described in the above embodiments; or it may exist independently and not assembled into the device / apparatus / system. The computer-readable storage medium carries one or more programs that, when executed, implement the method according to the embodiments of this disclosure.

[0058] According to embodiments of this disclosure, the computer-readable storage medium may be a non-volatile computer-readable storage medium, such as including, but not limited to: portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof. In this disclosure, the computer-readable storage medium may be any tangible medium that contains or stores a program that can be used by or in conjunction with an instruction execution system, apparatus, or device. For example, according to embodiments of this disclosure, the computer-readable storage medium may include ROM 502 and / or RAM 503 and / or one or more memories other than ROM 502 and RAM 503 described above.

[0059] Embodiments of this disclosure also include a computer program product comprising a computer program containing program code for performing the methods shown in the flowchart. When the computer program product is run on a computer system, the program code enables the computer system to implement the ground-penetrating radar loss tangent estimation method based on real-time spectrum provided in embodiments of this disclosure.

[0060] When the computer program is executed by the processor 501, it performs the functions defined in the system / apparatus of this disclosure embodiments. According to embodiments of this disclosure, the systems, apparatuses, modules, units, etc., described above can be implemented by computer program modules.

[0061] In one embodiment, the computer program may rely on a tangible storage medium such as an optical storage device or a magnetic storage device. In another embodiment, the computer program may also be transmitted and distributed in the form of signals over a network medium, and may be downloaded and installed via the communication section 509, and / or installed from a removable medium 511. The program code contained in the computer program can be transmitted using any suitable network medium, including but not limited to: wireless, wired, etc., or any suitable combination thereof.

[0062] In such an embodiment, the computer program can be downloaded and installed from a network via communication section 509, and / or installed from removable medium 511. When the computer program is executed by processor 501, it performs the functions defined in the system of this disclosure embodiment. According to embodiments of this disclosure, the systems, devices, apparatuses, modules, units, etc., described above can be implemented by computer program modules.

[0063] According to embodiments of this disclosure, program code for executing the computer programs provided in embodiments of this disclosure can be written in any combination of one or more programming languages. Specifically, these computational programs can be implemented using high-level procedural and / or object-oriented programming languages, and / or assembly / machine languages. Programming languages ​​include, but are not limited to, languages ​​such as Java, C++, Python, "C", or similar programming languages. The program code can execute entirely on the user's computing device, partially on the user's device, partially on a remote computing device, or entirely on a remote computing device or server. In cases involving remote computing devices, the remote computing device can be connected to the user's computing device via any type of network, including a local area network (LAN) or a wide area network (WAN), or it can be connected to an external computing device (e.g., via the Internet using an Internet service provider).

[0064] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of this disclosure. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions indicated in the blocks may occur in a different order than those indicated in the drawings. For example, two consecutively indicated blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in a block diagram or flowchart, and combinations of blocks in a block diagram or flowchart, may be implemented using a dedicated hardware-based system that performs the specified function or operation, or using a combination of dedicated hardware and computer instructions.

[0065] Those skilled in the art will understand that the features described in the various embodiments and / or claims of this disclosure can be combined or combined in various ways, even if such combinations or combinations are not explicitly described in this disclosure. In particular, the features described in the various embodiments and / or claims of this disclosure can be combined or combined in various ways without departing from the spirit and teachings of this disclosure. All such combinations and / or combinations fall within the scope of this disclosure.

[0066] The embodiments of this disclosure have been described above. However, these embodiments are for illustrative purposes only and are not intended to limit the scope of this disclosure. Although various embodiments have been described above, this does not mean that the measures in the various embodiments cannot be used advantageously in combination. The scope of this disclosure is defined by the appended claims and their equivalents. Various substitutions and modifications can be made by those skilled in the art without departing from the scope of this disclosure, and all such substitutions and modifications should fall within the scope of this disclosure.

Claims

1. A method for estimating the loss tangent of ground-penetrating radar based on real-time spectrum, comprising: Initial echo signal identification is performed based on the profile data map obtained from radar observation, so as to identify the surface echo signal corresponding to the profile data map; The incident signal spectrum of the radar is calculated based on the surface echo signal, and the theoretical relationship curve of the center frequency changing with time is obtained based on the incident signal spectrum and the wave equation satisfied by the electromagnetic wave in the medium. The theoretical relationship curve of the center frequency changing with time is used as the theoretical center frequency attenuation curve. Based on the profile data, time-frequency analysis is performed to obtain the instantaneous spectrum matrix of the radar signal during the detection process. The measured curve of the center frequency changing over time is calculated based on the instantaneous spectrum matrix, and this measured curve is used as the measured center frequency attenuation curve. Based on the theoretical center frequency attenuation curve and the measured center frequency attenuation curve, the ground-penetrating radar loss tangent estimation result is determined.

2. The method according to claim 1, wherein, The process of calculating the radar incident signal spectrum based on the surface echo signal, and obtaining the theoretical relationship curve of the center frequency changing with time based on the incident signal spectrum and the wave equation satisfied by electromagnetic waves propagating in the medium, and using the theoretical relationship curve of the center frequency changing with time as the theoretical center frequency attenuation curve, includes: The incident signal spectrum of the radar is calculated based on the surface echo signal using a windowed Fourier transform. Based on the incident signal spectrum and the wave equation satisfied by the electromagnetic wave propagation in the medium, a theoretical relationship is established for the change of the center frequency of the incident signal with time under a medium with an assumed loss tangent, so as to obtain the theoretical relationship curve of the change of the center frequency with time.

3. The method according to claim 1, wherein, Based on the aforementioned profile data, time-frequency analysis is performed to obtain the instantaneous spectrum matrix of the radar signal during the detection process, including: Using the short-time Fourier transform or S-transform method, time-frequency analysis is performed based on the profile data to obtain the instantaneous spectrum matrix of the radar signal during the detection process.

4. The method according to claim 1, wherein, The determination of the ground-penetrating radar loss tangent estimation result based on the theoretical center frequency attenuation curve and the measured center frequency attenuation curve includes: Based on the theoretical center frequency attenuation curve and the measured center frequency attenuation curve, the loss tangent estimation result of the ground penetrating radar is obtained using the least squares method.

5. A ground-penetrating radar loss tangent estimation device based on real-time spectrum, comprising: The first acquisition module is used to perform initial echo signal identification based on the profile data map obtained by radar observation, so as to identify the surface echo signal corresponding to the profile data map; The second acquisition module is used to calculate the incident signal spectrum of the radar based on the surface echo signal, and obtain the theoretical relationship curve of the center frequency changing with time based on the incident signal spectrum and the wave equation satisfied by the electromagnetic wave in the medium, and use the theoretical relationship curve of the center frequency changing with time as the theoretical center frequency attenuation curve. The third acquisition module is used to perform time-frequency analysis based on the profile data map to analyze and obtain the instantaneous spectrum matrix of the radar signal during the detection process, and calculate the measured curve of the center frequency changing with time based on the instantaneous spectrum matrix, and use the measured curve of the center frequency changing with time as the measured center frequency attenuation curve. as well as The determination module is used to determine the ground-penetrating radar loss tangent estimation result based on the theoretical center frequency attenuation curve and the measured center frequency attenuation curve.

6. The apparatus according to claim 5, wherein, The second obtaining module includes: The calculation unit is used to calculate the radar incident signal spectrum based on the surface echo signal using a windowed Fourier transform. The acquisition unit is used to establish, based on the wave equation satisfied by the electromagnetic wave propagating in the medium, the theoretical relationship between the center frequency of the incident signal and time under the assumed loss tangent value in the medium, so as to obtain the theoretical relationship curve of the center frequency changing with time.

7. The apparatus according to claim 5, wherein, The first obtaining module includes: The analysis unit is used to perform time-frequency analysis based on the profile data map using the short-time Fourier transform method or the S-transform method, so as to obtain the instantaneous spectrum matrix of the radar signal during the detection process.

8. The apparatus according to claim 5, wherein, The determining module is further configured to: Based on the theoretical center frequency attenuation curve and the measured center frequency attenuation curve, the loss tangent estimation result of the ground penetrating radar is obtained using the least squares method.

9. An electronic device, comprising: One or more processors; Storage device for storing one or more programs. Wherein, when the one or more programs are executed by the one or more processors, the one or more processors perform the method according to any one of claims 1 to 4.

10. A computer-readable storage medium having executable instructions stored thereon, which, when executed by a processor, cause the processor to perform the method according to any one of claims 1 to 4.

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