CN118209982A

CN118209982A - Digital elevation model reconstruction method, device, equipment and medium based on interference phase diagram

Info

Publication number: CN118209982A
Application number: CN202410326455.6A
Authority: CN
Inventors: 李超; 王泽玉; 刘小军; 方广有; 吴一戎
Original assignee: Aerospace Information Research Institute of CAS
Current assignee: Aerospace Information Research Institute of CAS
Priority date: 2024-03-21
Filing date: 2024-03-21
Publication date: 2024-06-18

Abstract

The invention provides a digital elevation model reconstruction method based on an interference phase diagram, which can be applied to the technical fields of radar imaging and radar signal processing. The digital elevation model reconstruction method based on the interference phase diagram comprises the following steps: generating an original interference phase diagram and a difference frequency interference phase diagram based on the antenna echo data; determining the unwrapping phase of each pixel in the original interference phase diagram based on the phase difference model and the unwrapping phase of each pixel in the difference frequency interference phase diagram; reconstructing a digital elevation model of the object to be detected based on the unwrapped phase of each pixel in the original interference phase map and the two-dimensional coordinates of each pixel. The disclosure also provides a digital elevation model reconstruction device, equipment and medium based on the interference phase diagram.

Description

Digital elevation model reconstruction method, device, equipment and medium based on interference phase diagram

Technical Field

The present disclosure relates to the field of radar imaging and radar signal processing, and in particular, to a digital elevation model reconstruction method, apparatus, device, and medium based on an interference phase diagram.

Background

The working wave band of the terahertz radar is (0.1 THz-10 THz), and the target to be detected can be detected and imaged through the radiation of the terahertz radar. By virtue of the short wavelength characteristic and the large bandwidth characteristic of the terahertz wave, the terahertz radar system has high-resolution imaging capability compared with a microwave radar system. For example, when the target to be detected is an entity such as an airplane, a ship, a vehicle and the like, the terahertz radar system can realize high-resolution imaging, and the identification accuracy of the target to be detected is improved.

In radar imaging algorithms, interference imaging techniques are increasingly being used, where the interference phase plays a key role. Because the interference phase has a main value and a winding period, when the variation amplitude of the interference phase exceeds a complete period, the phenomenon of interference phase winding can occur, so that the phase value is inaccurate. In terahertz synthetic aperture radar (Interferometric Synthetic Aperture Radar, inSAR) imaging, the high frequency characteristic of the terahertz radar makes the terahertz radar more sensitive to the change of terrain height, thereby exacerbating the winding density of interference phases.

Disclosure of Invention

In view of the foregoing, the present disclosure provides a digital elevation model reconstruction method, apparatus, device, and medium based on interferometric phase diagrams.

According to a first aspect of the present disclosure, there is provided a digital elevation model reconstruction method based on an interference phase map, including: generating an original interference phase diagram and a difference frequency interference phase diagram based on antenna echo data, wherein the antenna echo data is data formed by a reflected signal received by a radar system, and the reflected signal is formed by the reflection of a radar signal transmitted by the radar system by a target to be detected according to the embodiment of the disclosure; determining the unwrapping phase of each pixel in the original interference phase diagram based on the phase difference model and the unwrapping phase of each pixel in the difference frequency interference phase diagram; reconstructing a digital elevation model of the object to be detected based on the unwrapped phase of each pixel in the original interference phase map and the two-dimensional coordinates of each pixel.

According to an embodiment of the present disclosure, reconstructing a digital elevation model of an object to be detected based on unwrapping phases of each pixel in an original interference phase map and two-dimensional coordinates of each pixel, includes: acquiring the height of each pixel according to the unwrapping phase of each pixel in the original interference phase diagram; a digital elevation model is reconstructed based on the height of each pixel and the two-dimensional coordinates of each pixel.

According to an embodiment of the present disclosure, determining an unwrapping phase for each pixel in an original interferometric phase map based on a phase difference model and an unwrapping phase for each pixel in a difference frequency interferometric phase map includes: calculating the greatest common divisor of the wavelength of the difference frequency interference phase diagram and the wavelength of the original interference phase diagram; based on the greatest common divisor, calculating parameters of a difference frequency interference phase diagram and parameters of an original interference phase diagram; inputting the unwrapping phase of each pixel in the difference frequency interference phase diagram, the original phase of each pixel and the parameters of the difference frequency interference phase diagram into a phase difference model to obtain a first intermediate value of each pixel in the difference frequency interference phase diagram; inputting the original phase of each pixel in the original interference phase map and parameters of the original interference phase map to a phase difference model to obtain a second intermediate value of each pixel in the original interference phase map; and performing geometric operation by using the first intermediate value of each pixel in the difference frequency interference phase diagram and the second intermediate value of each pixel in the original interference phase diagram to obtain the unwrapping phase of each pixel in the original interference phase diagram.

According to an embodiment of the present disclosure, the antenna echo data includes main antenna echo data obtained by a main radar system and sub antenna echo data obtained by a sub radar system.

According to an embodiment of the present disclosure, generating an original interference phase map and a difference frequency interference phase map based on antenna echo data includes: for target antenna echo data, carrying out Fourier transform on the target antenna echo data to obtain distance bandwidth data, wherein the target antenna echo data is main antenna echo data or auxiliary antenna echo data; splitting the distance-oriented bandwidth data to obtain a plurality of distance-oriented sub-bandwidth data; respectively carrying out imaging processing on the range-wise bandwidth data and each range-wise sub-bandwidth data by using a range-Doppler algorithm to obtain a band diagram and a plurality of sub-band diagrams of the echo data of the target antenna, wherein the sub-band diagrams correspond to the range-wise sub-bandwidth data one by one; generating a difference frequency interference phase map based on the plurality of sub-band maps of the main antenna echo data and the plurality of sub-band maps of the auxiliary antenna echo data; an original interference phase map is generated based on the band map of the primary antenna echo data and the band map of the secondary antenna echo data.

According to an embodiment of the present disclosure, generating a difference frequency interference phase map based on a plurality of subband maps of primary antenna echo data and a plurality of subband maps of secondary antenna echo data, includes: performing conjugate processing on a plurality of sub-band diagrams of the echo data of the main antenna to obtain a main difference frequency interference diagram; performing conjugate processing on a plurality of sub-band diagrams of the echo data of the auxiliary antenna to obtain an auxiliary difference frequency interference diagram; and carrying out interference treatment on the main difference frequency interference pattern and the auxiliary difference frequency interference pattern to obtain a difference frequency interference phase diagram.

According to an embodiment of the present disclosure, generating an original interference phase map based on a band map of primary antenna echo data and a band map of secondary antenna echo data includes: aligning the band diagram of the secondary antenna echo data with the band diagram of the primary antenna echo data based on the distance difference value to obtain an aligned band diagram of the secondary antenna echo data; performing conjugate processing on the band diagram and the alignment band diagram of the echo data of the main antenna to obtain an original interference phase diagram; according to an embodiment of the disclosure, the distance difference is a distance difference between a first distance and a second distance, the first distance is a distance between the object to be detected and the primary radar system, and the second distance is a distance between the object to be detected and the secondary radar system.

According to an embodiment of the present disclosure, performing interference processing on a primary difference frequency interference pattern and a secondary difference frequency interference pattern to obtain a difference frequency interference phase pattern, including: based on the distance difference, aligning the auxiliary difference frequency interference pattern with the main difference frequency interference pattern to obtain an aligned difference frequency interference pattern of the auxiliary difference frequency interference pattern; and performing conjugate processing on the main difference frequency interference pattern and the alignment difference frequency interference pattern to obtain a difference frequency interference phase pattern.

A second aspect of the present disclosure provides a digital elevation model reconstruction apparatus based on an interference phase map, comprising: the generating module is used for generating an original interference phase diagram and a difference frequency interference phase diagram based on antenna echo data, wherein the antenna echo data are data formed by reflection signals received by a radar system, and the reflection signals are formed by reflection of radar signals transmitted by the radar system by an object to be detected; the determining module is used for determining the unwrapping phase of each pixel in the original interference phase diagram based on the phase difference model and the unwrapping phase of each pixel in the difference frequency interference phase diagram; and the reconstruction module is used for reconstructing a digital elevation model of the object to be detected based on the unwrapping phase of each pixel in the original interference phase diagram and the two-dimensional coordinate of each pixel.

A third aspect of the present disclosure provides an electronic device, comprising: one or more processors; and a memory for storing one or more computer programs, wherein the one or more processors execute the one or more computer programs to implement the steps of the method.

A fourth aspect of the present disclosure also provides a computer readable storage medium having stored thereon a computer program or instructions which, when executed by a processor, implement the steps of the above method.

According to the embodiment of the disclosure, by acquiring the unwrapping phase of each pixel in the original interference phase map using the difference frequency interference phase map, the accuracy of the unwrapping phase can be improved as compared with directly acquiring the unwrapping phase of each pixel in the original interference phase map. The accuracy of the digital elevation model can be improved by reconstructing based on the accurate unwrapping phase.

Drawings

The foregoing and other objects, features and advantages of the disclosure will be more apparent from the following description of embodiments of the disclosure with reference to the accompanying drawings, in which:

FIG. 1 schematically illustrates a flow chart of a digital elevation model reconstruction method based on an interference phase map in accordance with an embodiment of the present disclosure;

FIG. 2 schematically illustrates a data flow diagram of a digital elevation model reconstruction method based on an interferometric phase map in accordance with an embodiment of the present disclosure;

FIG. 3 schematically illustrates a schematic of phase versus height in a phase difference model according to an embodiment of the present disclosure;

FIG. 4A schematically illustrates a schematic diagram of an original digital elevation model of an object to be detected, according to an embodiment of the present disclosure;

FIG. 4B schematically illustrates a schematic diagram of an original interference phase map generated in accordance with an embodiment of the present disclosure;

FIG. 4C schematically illustrates a schematic diagram of a difference frequency interferometry phase map generated according to an embodiment of the disclosure;

FIG. 5A schematically illustrates a schematic diagram of a digital elevation model obtained after processing an original interference phase map based on a conventional unwrapping method;

FIG. 5B schematically illustrates an error analysis schematic of a digital elevation model obtained after processing an original interference phase map based on a conventional unwrapping method;

FIG. 5C schematically illustrates a schematic diagram of a digital elevation model from processing an original interference phase map in accordance with an embodiment of the present disclosure;

FIG. 5D schematically illustrates an error analysis schematic of a digital elevation model obtained by processing an original interferometric phase map in accordance with an embodiment of the present disclosure;

FIG. 6 schematically illustrates a block diagram of a digital elevation model reconstruction apparatus based on an interferometric phase map in accordance with an embodiment of the present disclosure; and

Fig. 7 schematically illustrates a block diagram of an electronic device suitable for implementing an interferometric phase map-based digital elevation model reconstruction method, in accordance with an embodiment of the present disclosure.

Detailed Description

Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. It should be understood that the description is only exemplary and is not intended to limit the scope of the present disclosure. In the following detailed description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the embodiments of the present disclosure. It may be evident, however, that one or more embodiments may be practiced without these specific details. In addition, in the following description, descriptions of well-known structures and techniques are omitted so as not to unnecessarily obscure the concepts of the present disclosure.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. The terms "comprises," "comprising," and/or the like, as used herein, specify the presence of stated features, steps, operations, and/or components, but do not preclude the presence or addition of one or more other features, steps, operations, or components.

All terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art unless otherwise defined. It should be noted that the terms used herein should be construed to have meanings consistent with the context of the present specification and should not be construed in an idealized or overly formal manner.

Where a convention analogous to "at least one of A, B and C, etc." is used, in general such a convention should be interpreted in accordance with the meaning of one of skill in the art having generally understood the convention (e.g., "a system having at least one of A, B and C" would include, but not be limited to, systems having a alone, B alone, C alone, a and B together, a and C together, B and C together, and/or A, B, C together, etc.).

In the technical solution of the present disclosure, the related user information (including, but not limited to, user personal information, user image information, user equipment information, such as location information, etc.) and data (including, but not limited to, data for analysis, stored data, displayed data, etc.) are information and data authorized by the user or sufficiently authorized by each party, and the related data is collected, stored, used, processed, transmitted, provided, disclosed, applied, etc. in compliance with relevant laws and regulations and standards, necessary security measures are taken, no prejudice to the public order colloquia is provided, and corresponding operation entries are provided for the user to select authorization or rejection.

In the scenario of using personal information to make an automated decision, the method, the device and the system provided by the embodiment of the disclosure provide corresponding operation inlets for users, so that the users can choose to agree or reject the automated decision result; if the user selects refusal, the expert decision flow is entered. The expression "automated decision" here refers to an activity of automatically analyzing, assessing the behavioral habits, hobbies or economic, health, credit status of an individual, etc. by means of a computer program, and making a decision. The expression "expert decision" here refers to an activity of making a decision by a person who is specializing in a certain field of work, has specialized experience, knowledge and skills and reaches a certain level of expertise.

In carrying out the present disclosure, the applicant has found that the prior art has the following technical drawbacks: the wavelength of the terahertz radar is in millimeter magnitude, the sensitivity to the change of the terrain height is high, meanwhile, the winding density of interference phases is increased, and a good disentanglement effect is difficult to realize by a conventional algorithm. In addition, due to severe relief, the continuity of the interference phase is poor, so that the interference phase has a blurring phenomenon, the unwrapping effect of the interference phase is poor, and the reconstruction effect of the digital elevation model is poor.

The embodiment of the disclosure provides a digital elevation model reconstruction method based on an interference phase diagram, which is based on antenna echo data, wherein the antenna echo data is data formed by a reflection signal received by a radar system, and the reflection signal is formed by the reflection of a radar signal transmitted by the radar system by a target to be detected; determining the unwrapping phase of each pixel in the original interference phase diagram based on the phase difference model and the unwrapping phase of each pixel in the difference frequency interference phase diagram; reconstructing a digital elevation model of the object to be detected based on the unwrapped phase of each pixel in the original interference phase map and the two-dimensional coordinates of each pixel.

Fig. 1 schematically illustrates a flow chart of a digital elevation model reconstruction method based on an interference phase map according to an embodiment of the present disclosure.

As shown in fig. 1, the digital elevation model reconstruction based on the interference phase map of this embodiment includes operations S101 to S103.

In operation S101, an original interference phase map and a difference frequency interference phase map are generated based on the antenna echo data.

According to an embodiment of the present disclosure, the antenna echo data is data formed by a reflected signal received by the radar system, the reflected signal being formed by a radar signal transmitted by the radar system being reflected by an object to be detected.

According to an embodiment of the disclosure, the radar system may be a terahertz radar system, the original interference phase map may be an original terahertz interference phase map, and the difference frequency interference phase map may be a terahertz difference frequency interference phase map.

According to an embodiment of the disclosure, the antenna echo data may be data obtained by the radar system performing multiple scans of the target to be detected at different time points.

According to the embodiment of the disclosure, the antenna echo data of each radar system can be obtained by respectively preprocessing the original antenna echo data of a plurality of radar systems. And selecting the antenna echo data of each radar system as interference pairs, and performing interference processing and the like on each interference pair to obtain a plurality of original interference phases. And combining the plurality of original interference phases according to a preset sequence to obtain an original interference phase diagram.

According to the embodiment of the disclosure, the antenna echo data of each radar system can be split to obtain a plurality of antenna echo sub-data. And respectively carrying out preset processing on the multiple antenna echo sub-data of each radar system in the multiple radar systems to obtain a difference frequency diagram of each radar system. And carrying out preset combination on the difference frequency graphs of each radar system to obtain a difference frequency interference phase graph.

In operation S102, the unwrapping phase of each pixel in the original interference phase map is determined based on the phase difference model and the unwrapping phase of each pixel in the difference frequency interference phase map.

According to embodiments of the present disclosure, the phase difference model may model each pixel value in the difference frequency interferogram with each pixel value in the original interference phase map.

According to the embodiment of the disclosure, the unwrapped phase of each pixel in the difference frequency interference phase map may be input to the phase difference model, to obtain a first result of each pixel in the difference frequency interference phase map. And inputting the unwrapping phase of each pixel in the original interference phase diagram to the phase difference model to obtain a second result of each pixel in the original interference phase diagram. And solving the unwrapped phase value in the second result of each pixel in the original interference phase map by using the first result of each pixel in the difference frequency interference phase map.

In operation S103, a digital elevation model of the object to be detected is reconstructed based on the unwrapped phase of each pixel in the original interference phase map and the two-dimensional coordinates of each pixel.

According to the embodiment of the disclosure, the digital elevation model of the object to be detected is obtained by reconstructing the unwrapping phase of each pixel and the two-dimensional coordinates of each pixel in the original interference phase map by using data processing software such as remote sensing data processing software.

According to an embodiment of the present disclosure, determining the unwrapping phase of each pixel in the original interference phase map based on the phase difference model and the unwrapping phase of each pixel in the difference frequency interference phase map may include the operations of: calculating the greatest common divisor of the wavelength of the difference frequency interference phase diagram and the wavelength of the original interference phase diagram; based on the greatest common divisor, calculating parameters of a difference frequency interference phase diagram and parameters of an original interference phase diagram; inputting the unwrapping phase of each pixel in the difference frequency interference phase diagram, the original phase of each pixel and the parameters of the difference frequency interference phase diagram into a phase difference model to obtain a first intermediate value of each pixel in the difference frequency interference phase diagram; inputting the original phase of each pixel in the original interference phase map and parameters of the original interference phase map to a phase difference model to obtain a second intermediate value of each pixel in the original interference phase map; and performing geometric operation by using the first intermediate value of each pixel in the difference frequency interference phase diagram and the second intermediate value of each pixel in the original interference phase diagram to obtain the unwrapping phase of each pixel in the original interference phase diagram.

According to embodiments of the present disclosure, a phase difference model of an original interference phase map and a difference frequency interference phase map may be constructed based on a Chinese Remainder Theorem (CRT) to achieve joint phase unwrapping. The parameters of the difference frequency interference phase diagram and the parameters of the original interference phase diagram can be obtained by adopting the following formula:

Where λ ₀ represents the greatest common divisor, λ ₁ represents the wavelength of the original interference phase diagram, λ ₂ represents the wavelength of the difference frequency interference phase diagram, c represents the speed of light, λ ₁＝c/δf,λ₂＝c/f_c,f_c represents the frequency of the original interference phase diagram, and δf represents the frequency of the difference frequency interference phase diagram. In the case where i is equal to 1, m _i represents a parameter of the original interference phase map. In the case where i is equal to 2, m _i represents a parameter of the difference-frequency interference phase diagram.

According to an embodiment of the present disclosure, the phase difference model may be expressed, for example, using the following formula:

where dh denotes the relative height change, such as the term height change between adjacent pixels, Representing a relative phase difference, such as an interference phase difference between adjacent pixels. H can be used instead of dh to represent an absolute height value, and/>Substitution/>Representing the absolute phase value. k _i denotes an unwrapping phase of a pixel, B denotes a preset baseline length, α denotes a preset baseline tilt angle, θ denotes a down view angle of the radar system, and R denotes a distance between an object to be detected and the radar system.

According to the embodiment of the disclosure, the unwrapped phase of the second intermediate value of each pixel in the original interference phase map can be inversely unwrapped by using the first intermediate value of each pixel in the difference frequency interference phase map, so as to obtain the unwrapped phase of each pixel in the original interference phase map.

According to the embodiment of the disclosure, the unwrapping phase of the original interference phase map is obtained through the phase difference model and the difference frequency interference phase map, and compared with a conventional two-dimensional phase unwrapping algorithm, the unwrapping phase of the original interference phase map is smaller in error and higher in unwrapping precision.

According to an embodiment of the present disclosure, generating an original interference phase map and a difference frequency interference phase map based on antenna echo data may include the operations of: for target antenna echo data, carrying out Fourier transform on the target antenna echo data to obtain distance bandwidth data, wherein the target antenna echo data is main antenna echo data or auxiliary antenna echo data; splitting the distance-oriented bandwidth data to obtain a plurality of distance-oriented sub-bandwidth data; respectively carrying out imaging processing on the range-wise bandwidth data and each range-wise sub-bandwidth data by using a range-Doppler algorithm to obtain a band diagram and a plurality of sub-band diagrams of the echo data of the target antenna, wherein the sub-band diagrams correspond to the range-wise sub-bandwidth data one by one; generating a difference frequency interference phase map based on the plurality of sub-band maps of the main antenna echo data and the plurality of sub-band maps of the auxiliary antenna echo data; an original interference phase map is generated based on the band map of the primary antenna echo data and the band map of the secondary antenna echo data.

According to the embodiment of the disclosure, the distance-to-bandwidth data of the target antenna echo data can be equally divided into a plurality of sets with the same distance-to-sampling points, and each set is formed into one distance-to-sub-bandwidth data.

According to the embodiment of the disclosure, for the main antenna echo data, the pixel values of the same coordinates in each of the plurality of sub-band diagrams may be initially processed to obtain a difference frequency diagram corresponding to the main antenna echo data. For the secondary antenna echo data, the same initial processing can be performed on the pixel values with the same coordinates in each of the plurality of sub-band diagrams, so as to obtain a difference frequency diagram corresponding to the secondary antenna echo data. And the difference frequency interference phase diagram is obtained by reprocessing pixels at the same coordinate positions of the difference frequency diagram corresponding to the main antenna echo data and the difference frequency diagram corresponding to the auxiliary antenna echo data, such as interference processing and the like, and taking the processed values as pixel values of the difference frequency interference phase diagram at the same coordinate.

According to the embodiment of the disclosure, pixel values of the same coordinates in the band diagrams of the main antenna echo data and the band diagrams of the auxiliary antenna echo data are subjected to interference processing and the like, and the processed values are used as pixel values of an original interference phase diagram at the same coordinates to obtain the original interference phase diagram.

For example, the distance to bandwidth data of the target antenna echo data may be halved into the distance to sampling points, to obtain two distance to sub-bandwidth data. And respectively carrying out imaging processing on the range-wise bandwidth data and each range-wise sub-bandwidth data by using a range-Doppler algorithm to obtain a band diagram and two sub-band diagrams of the echo data of the target antenna.

When the target antenna echo data is main antenna echo data, pixels in a band diagram of the main antenna echo data can be represented by the following formula:

the pixels of the first subband map of the main antenna echo data may be represented using the following formula:

the pixels of the second sub-band map of the main antenna echo data may be represented using the following formula:

when the target antenna echo data is the secondary antenna echo data, the pixels in the band diagram of the secondary antenna echo data may be represented by the following formula:

the pixels of the first subband map of the secondary antenna echo data may be represented using the following formula:

the pixels of the second sub-band map of the secondary antenna echo data may be represented using the following formula:

Where s ₁ denotes a pixel in a band diagram of main antenna echo data, s ₂ denotes a pixel in a band diagram of sub-antenna echo data, s ₁₁ denotes a pixel of a first sub-band diagram of main antenna echo data, s ₁₂ denotes a pixel of a second sub-band diagram of main antenna echo data, s ₂₁ denotes a pixel of a first sub-band diagram of sub-antenna echo data, and s ₂₂ denotes a pixel of a second sub-band diagram of sub-antenna echo data. R ₁ represents the distance between the object to be detected and the primary radar system, and R ₂ represents the distance between the object to be detected and the secondary radar system. p _a (η) is an azimuth impulse function, specifically a sinc function, representing an azimuth impulse function of the target to be detected, where η=0. N and N _sub represent distance-wise sampling points before and after splitting of the distance-wise bandwidth data, respectively, and l _sub represent distance-wise sampling points before and after splitting of the distance-wise bandwidth data, respectively, l=0.

F _c denotes the frequency of the distance-wise bandwidth data, and the subband center frequencies are f _1c denotes the frequency of the first distance-wise subband data, and f _2c denotes the frequency of the second distance-wise subband data, respectively. In the case where the total bandwidth of the distance-wise bandwidth data is B _w, it is possible to obtain: f _1c＝f_c-B_w/2,f_2c＝f_c+B_w/2.

According to an embodiment of the present disclosure, generating a difference frequency interference phase map based on a plurality of sub-band maps of main antenna echo data and a plurality of sub-band maps of sub-antenna echo data may include the operations of: performing conjugate processing on a plurality of sub-band diagrams of the echo data of the main antenna to obtain a main difference frequency interference diagram; performing conjugate processing on a plurality of sub-band diagrams of the echo data of the auxiliary antenna to obtain an auxiliary difference frequency interference diagram; and carrying out interference treatment on the main difference frequency interference pattern and the auxiliary difference frequency interference pattern to obtain a difference frequency interference phase diagram.

According to the embodiment of the disclosure, the conjugation processing is performed on a plurality of sub-band diagrams of the echo data of the main antenna to obtain a main difference frequency interference diagram, which can be expressed by adopting the following formula:

Where s _1Δf represents the pixel value of the primary difference frequency interferogram.

According to the embodiment of the disclosure, the conjugation processing is performed on a plurality of sub-band diagrams of the echo data of the auxiliary antenna to obtain an auxiliary difference frequency interference diagram, which can be expressed by adopting the following formula:

where s _2Δf represents the pixel value of the secondary difference frequency interferogram.

According to the embodiment of the disclosure, the main difference frequency interference diagram and the auxiliary difference frequency interference diagram can be preprocessed to obtain the preprocessed main diagram and auxiliary diagram, so that the pixel values with the same coordinates in the main diagram and the auxiliary diagram can represent the antenna echo data of the same sampling point. And performing conjugate processing on the pixel values of the same coordinates of the main graph and the auxiliary graph to obtain processed pixel values, wherein the processed pixel values are used as the pixel values of the same coordinates as the same coordinates in the difference frequency interference phase graph.

According to the embodiment of the disclosure, the difference frequency interference graph with sparse interference fringes can be obtained by performing conjugate processing on the sub-band graph, and the difference frequency interference graph comprises a main difference frequency interference graph and a sub-difference frequency interference graph.

According to an embodiment of the present disclosure, generating an original interference phase map based on the band map of the main antenna echo data and the band map of the sub antenna echo data may include the operations of: aligning the band diagram of the secondary antenna echo data with the band diagram of the primary antenna echo data based on the distance difference value to obtain an aligned band diagram of the secondary antenna echo data; and carrying out conjugate processing on the band diagram and the alignment band diagram of the echo data of the main antenna to obtain an original interference phase diagram.

According to the embodiment of the disclosure, the skew difference can be calculated through zero height, and the band diagram of the secondary antenna echo data and the band diagram of the primary antenna echo data are aligned according to the skew difference and interpolation processing.

According to the embodiment of the disclosure, the pixel values of the same coordinates of the band diagram and the alignment band diagram of the main antenna echo data are subjected to conjugation processing to obtain an original interference phase diagram, which can be expressed by the following formula:

Where s represents the pixel value of the original interference phase map and s ₂' represents the pixel value of the alignment band map.

According to an embodiment of the disclosure, the distance difference is a distance difference between a first distance and a second distance, the first distance is a distance between the object to be detected and the primary radar system, and the second distance is a distance between the object to be detected and the secondary radar system.

According to an embodiment of the disclosure, performing interference processing on the primary difference frequency interference pattern and the secondary difference frequency interference pattern to obtain a difference frequency interference phase map may include the following operations: based on the distance difference, aligning the auxiliary difference frequency interference pattern with the main difference frequency interference pattern to obtain an aligned difference frequency interference pattern of the auxiliary difference frequency interference pattern; and performing conjugate processing on the main difference frequency interference pattern and the alignment difference frequency interference pattern to obtain a difference frequency interference phase pattern.

According to the embodiment of the disclosure, the primary difference frequency interference diagram and the secondary difference frequency interference diagram can be preprocessed according to the distance difference value, so that the preprocessed primary diagram and secondary diagram are obtained, and pixel values with the same coordinates in the primary diagram and the secondary diagram can represent antenna echo data of the same sampling point. And performing conjugate processing on the pixel values of the same coordinates of the main graph and the auxiliary graph to obtain processed pixel values, wherein the processed pixel values are used as the pixel values of the same coordinates as the same coordinates in the difference frequency interference phase graph.

According to the embodiment of the disclosure, the pixel values of the same coordinates of the main difference frequency interference pattern and the auxiliary difference frequency interference pattern are subjected to interference processing to obtain a difference frequency interference phase pattern, which can be represented by the following formula:

Where s _Δf represents the pixel value of the difference frequency interference phase map.

According to an embodiment of the present disclosure, reconstructing a digital elevation model of an object to be detected based on unwrapping phases of each pixel in an original interference phase map and two-dimensional coordinates of each pixel may include the operations of: acquiring the height of each pixel according to the unwrapping phase of each pixel in the original interference phase diagram; a digital elevation model is reconstructed based on the height of each pixel and the two-dimensional coordinates of each pixel.

According to the embodiment of the disclosure, by establishing a conversion formula of the height and the unwrapping phase, after the unwrapping phase of the pixel is acquired, the unwrapping phase can be used to solve the value of the height in the conversion formula.

According to embodiments of the present disclosure, the height of each pixel and the two-dimensional coordinates of each pixel may be processed using associated data processing software to obtain a digital elevation model.

According to embodiments of the present disclosure, by unwrapping the phase, directly obtaining the height may increase the reconstruction speed of reconstructing the digital elevation model.

Fig. 2 schematically illustrates a data flow diagram of a digital elevation model reconstruction method based on an interference phase map in accordance with an embodiment of the present disclosure.

As shown in fig. 2, fourier transformation is performed on the main antenna echo data and the sub-antenna echo data, respectively, to obtain distance-to-bandwidth data 1 of the main antenna echo data and distance-to-bandwidth data 2 of the sub-antenna echo data. And splitting the distance-oriented bandwidth data 1 and the distance-oriented bandwidth data 2 respectively to obtain distance-oriented sub-bandwidth data 1 and distance-oriented sub-bandwidth data 2 of the main antenna echo data, and distance-oriented sub-bandwidth data 3 and distance-oriented sub-bandwidth data 4 of the auxiliary antenna echo data.

According to an embodiment of the present disclosure, the main antenna echo data and the sub antenna echo data correspond to the same target to be detected.

According to the embodiment of the disclosure, the sub-band diagram 3 and the sub-band diagram 4 of the range-wise bandwidth data 1 are obtained by performing imaging processing on the range-wise bandwidth data 1, the range-wise bandwidth data 2, the range-wise sub-bandwidth data 1, the range-wise sub-bandwidth data 2, the range-wise sub-bandwidth data 3 and the range-wise sub-bandwidth data 4 by using a range-doppler algorithm, respectively.

According to the embodiment of the disclosure, the subband diagram 1 and the subband diagram 2 are subjected to conjugation processing, so as to obtain a main difference frequency interference diagram. And carrying out conjugation processing on the sub-band diagram 3 and the sub-band diagram 4 to obtain a sub-difference frequency interference diagram. And carrying out interference treatment on the main difference frequency interference pattern and the auxiliary difference frequency interference pattern to obtain a difference frequency interference phase diagram. And carrying out interference processing on the main band diagram and the sub band diagram to obtain an original interference phase diagram.

According to the embodiment of the disclosure, the fast two-dimensional phase unwrapping can be used on the difference frequency interference phase map, so as to obtain the unwrapped phase of each pixel in the difference frequency interference phase map. The unwrapping phase of each pixel point in the original interference phase map can be determined by the unwrapping phase and the phase difference model of each pixel in the difference frequency interference phase map. And reconstructing the unwrapping phase of each pixel and the two-dimensional coordinates of each pixel in the original interference phase diagram to obtain a digital elevation model of the target to be detected.

Fig. 3 schematically illustrates a schematic of phase versus height in a phase difference model according to an embodiment of the present disclosure.

According to an embodiment of the present disclosure, a phase principal value of a pixel is obtained from a difference frequency interference phase map of target antenna echo dataThe value interval is [ -pi, pi). Absolute phase value of pixel/>The winding period k is added, and thus the phase of the pixel can be expressed using the following formula:

According to an embodiment of the present disclosure, the targets to be detected are the same for both the primary and secondary radar systems. The pixel at the same coordinate position of the original interference phase diagram and the difference frequency interference phase diagram has the same contained height. Based on the phase and height conversion formulas, the phase and height conversion formulas in the original interference phase diagram and the difference frequency interference phase diagram can be obtained respectively. The conversion formula can be expressed by the following formula:

Wherein, in the case that i is equal to1, The phase of the difference frequency interference phase diagram is represented, and the formula (14) represents the conversion formula of the phase and the height in the difference frequency interference phase diagram. in case i is equal to 2,/>Representing the phase of the original interference phase map, equation (14) represents the phase versus height conversion equation in the original interference phase map. And (3) combining the formula (13) with the formula (14) to obtain the phase difference model.

As shown in fig. 3, a ₁ represents a primary radar system, and a ₂ represents a secondary radar system. When the target to be detected has a certain height, the side view angle theta of the main radar system can generate strabismus angle change delta theta. According to imaging characteristics of synthetic aperture radar (SYNTHETIC APERTURE RADAR, SAR) oblique projection, if a projection point of a point P of an object to be detected on a reference horizontal plane is represented by a distance from P ₀,A₁ to P ₀, and a distance from R ₁,A₁ to P is represented by R ₁, R ₁＝R₁ is set. The distance from a ₂ to P ₀ is denoted R ₂,A₂ to P as R ₂, resulting in R ₂≠R₂ due to the elevation relief resulting in a squint angle change δθ. The skew δr=r ₁-R₂ includes land phase information due to a distance increase and terrain phase information due to a height fluctuation.

From the structure of the skew delta R and the baseline, it is possible to obtain:

Wherein θ ₀ represents the lower viewing angle of P ₀, and B represents the preset baseline length. Since the height fluctuation is short with respect to the pitch, the difference between the lower viewing angles of a ₁ and a ₂ is small in the case of a short base line, and the following condition is satisfied:

cosδθ≈1 sinδθ≈δθ (16)

after applying equation (16) to equation (15), the slope distance difference can be expressed by the following equation:

δR＝B sin(θ₀-α)+B cos(θ₀-α)δθ (17)

According to embodiments of the present disclosure, the skew difference may be converted into a phase difference by the antenna echo data. By employing a dual antenna single pass version for the primary and secondary radar systems, the number of antenna returns may be expressed as 2pi/λ. Converting equation (17) into an interference model, i.e

Wherein,Irrespective of the amount of side view angle variation of the radar system; the right side of the equal sign of equation (18) represents the terrain phase, the interference phase of point P ₀, i.e., the land phase of point P

Wherein,Indicating the interference phase of point P ₀, since the baseline is small relative to the skew, parallel baseline B _P is indicated as:

B_||＝δR＝r₁-r₂＝B sin(θ-α) (20)

Thus, applying equation (20) to equation (19) yields:

then the topography phase The following formula can be used:

furthermore, the following formula can be found based on fig. 3:

The deformation processing is performed on the formula (23) based on the triangular relation, the following formula can be obtained:

the angle change amount δθ of the oblique angle can be expressed by the following formula:

/>

Applying equation (25) to equation (22) to obtain the terrain phase The following formula can be used:

According to an embodiment of the present disclosure, the phase to height conversion equation, equation (14), may be derived from equation (26).

According to the embodiment of the disclosure, the imaging resolution of the digital elevation model of the target to be detected can be ensured under the same baseline distribution by adopting a double-antenna single-navigation mode instead of a single-antenna double-navigation mode for the main radar system and the auxiliary radar system.

According to embodiments of the present disclosure, experiments were performed to demonstrate the effectiveness of the disclosed methods by utilizing the disclosed methods. Table 1 shows the system parameters used for the experiment, and the different positions of the target to be detected have different heights. Parameters of the radar system, such as altitude, range resolution, step frequency and center frequency, baseline length, baseline tilt angle, number of samples of the object to be detected, and bandwidth data of the target antenna echo data, sub-bandwidth data, frequency of the first range-to-sub-bandwidth data of the target antenna echo data, and frequency of the second range-to-sub-bandwidth data of the target antenna echo data are included in table 1. Based on the system parameters, a raw digital elevation model of the object to be detected can be generated using the relevant data software.

TABLE 1

Fig. 4A schematically illustrates a schematic diagram of an original digital elevation model of an object to be detected, according to an embodiment of the present disclosure.

As shown in fig. 4A, the abscissa of the original digital elevation model of the object to be detected represents distance, the ordinate represents azimuth, and the pixel value represents altitude. The original digital elevation model includes a first trough 410, a first peak 420, a second peak 430, a second trough 440, and a third peak 450. First trough 410 and second trough 440 are each relatively low center but relatively high perimeter regions, and first peak 420, second peak 430, and third peak 450 are each relatively high center but relatively low perimeter regions.

According to an embodiment of the present disclosure, the value of the center position of the first peak 420 is a peak value representing a maximum value in the height distribution of the first peak 420. The value at the center of first trough 410 is a peak representing the minimum value in the height distribution of first trough 410.

Fig. 4B schematically illustrates a schematic diagram of an original interference phase map generated in accordance with an embodiment of the present disclosure.

As shown in fig. 4B, the pixel values in the original interference phase map represent phase values, and the range of values of the phases is represented by color bars. There are a plurality of coils in the original interference phase map, each coil being formed by a plurality of phase values connected. The coils with blue to red jumps exist in the coils, and the coils with red to blue jumps also exist, so that the absolute phase value of the original interference phase diagram is indicated to be in a range which is not within [ -pi, pi ].

Fig. 4C schematically illustrates a schematic diagram of a difference frequency interferometry phase map generated according to an embodiment of the disclosure.

As shown in fig. 4C, the difference frequency interference phase diagram includes a first region 460, a second region 470, and a third region 480, and the coils in the first region 460, the second region 470, and the third region 480 are all coils without color jump, which indicates that the phase values in the difference frequency interference phase diagram have continuity.

Fig. 5A schematically shows a schematic diagram of a digital elevation model obtained after processing an original interference phase map based on a conventional unwrapping method.

As shown in fig. 5A, the digital elevation model obtained by the conventional unwrapping method includes a blue area, a light blue area, and a red area, wherein the blue area represents an area with a height of 0 in the digital elevation model, the light blue area represents an area with a height of approximately 5 in the digital elevation model, and the red area represents an area with a height of approximately 15 in the digital elevation model.

Fig. 5B schematically shows an error analysis schematic of a digital elevation model obtained after processing an original interference phase map based on a conventional unwrapping method.

As shown in FIG. 5B, the digital elevation model obtained by the conventional unwrapping method is compared with the original digital elevation model to obtain the blue region of FIG. 5A with the height error interval of [ -2,0], the light blue region with the height error interval of [ -4, -2], and the red region with the height error interval of [ -14, -8].

Fig. 5C schematically illustrates a schematic diagram of a digital elevation model from processing an original interference phase map in accordance with an embodiment of the present disclosure.

As shown in fig. 5C, the digital elevation model obtained by the embodiments of the present disclosure includes a first trough 510, a first peak 520, a second peak 530, a second trough 540, and a third peak 550.

FIG. 5D schematically illustrates an error analysis schematic of a digital elevation model from processing an original interference phase map in accordance with an embodiment of the present disclosure.

As shown in fig. 5D, the digital elevation model obtained in the embodiment of the present disclosure is compared with the original digital elevation model, so that errors in five areas of the first trough 510, the first peak 520, the second peak 530, the second trough 540, and the third peak 550 are all 0.

As can be seen from fig. 5C and fig. 5D, the present disclosure determines the unwrapping phase of the original interference phase map through the phase difference model and the difference frequency phase map, and further reconstructs the digital elevation model of the target to be detected, so as to obtain a height error of 0 in the digital elevation model. Compared with a digital elevation model obtained after the original interference phase map is subjected to the conventional unwrapping method, the method disclosed by the invention can obviously improve the unwrapping phase precision of the original interference phase map and greatly reduce the height error of the digital elevation model.

According to the embodiment of the disclosure, the method disclosed by the disclosure can improve the application range of a radar system such as a terahertz radar system, and provides feasibility and technical foundation for the wide use of the radar system.

Based on the digital elevation model reconstruction method based on the interference phase map, the invention also provides a digital elevation model reconstruction device based on the interference phase map. The device will be described in detail below in connection with fig. 6.

Fig. 6 schematically illustrates a block diagram of a digital elevation model reconstruction apparatus based on an interference phase map according to an embodiment of the present disclosure.

As shown in fig. 6, the digital elevation model reconstruction apparatus based on the interference phase map of this embodiment includes a generating module 610, a determining module 620, and a reconstructing module 630.

A generating module 610 is configured to generate an original interference phase map and a difference frequency interference phase map based on the antenna echo data.

A determining module 620, configured to determine the unwrapping phase of each pixel in the original interference phase map based on the phase difference model and the unwrapping phase of each pixel in the difference frequency interference phase map.

The reconstruction module 630 is configured to reconstruct a digital elevation model of the object to be detected based on the unwrapped phase of each pixel in the original interference phase map and the two-dimensional coordinates of each pixel.

According to an embodiment of the present disclosure, the reconstruction module 630 includes: an acquisition unit and a reconstruction unit.

And the acquisition unit is used for acquiring the height of each pixel according to the unwrapping phase of each pixel in the original interference phase diagram.

And a reconstruction unit for reconstructing the digital elevation model based on the height of each pixel and the two-dimensional coordinates of each pixel.

According to an embodiment of the present disclosure, the determining module 620 includes: the device comprises a first computing unit, a second computing unit, a first input unit, a second input unit and a geometric operation unit.

And the first calculation unit is used for calculating the greatest common divisor of the wavelength of the difference frequency interference phase diagram and the wavelength of the original interference phase diagram.

And the second calculation unit is used for calculating the parameters of the difference frequency interference phase diagram and the parameters of the original interference phase diagram based on the greatest common divisor.

The first input unit is used for inputting the unwrapping phase of each pixel in the difference frequency interference phase diagram, the original phase of each pixel and the parameters of the difference frequency interference phase diagram to the phase difference model to obtain a first intermediate value of each pixel in the difference frequency interference phase diagram.

And the second input unit is used for inputting the original phase of each pixel in the original interference phase diagram and the parameters of the original interference phase diagram to the phase difference model to obtain a second intermediate value of each pixel in the original interference phase diagram.

And the geometric operation unit is used for carrying out geometric operation by utilizing the first intermediate value of each pixel in the difference frequency interference phase diagram and the second intermediate value of each pixel in the original interference phase diagram to obtain the unwrapping phase of each pixel in the original interference phase diagram.

According to an embodiment of the present disclosure, the generating module 610 includes: the device comprises a transformation unit, a splitting unit, an imaging processing unit, a first generating unit and a second generating unit.

And the transformation unit is used for carrying out Fourier transformation on the target antenna echo data to obtain distance bandwidth data, wherein the target antenna echo data is main antenna echo data or auxiliary antenna echo data.

The splitting unit is used for splitting the distance-oriented bandwidth data to obtain a plurality of distance-oriented sub-bandwidth data.

And the imaging processing unit is used for respectively carrying out imaging processing on the range-wise bandwidth data and each range-wise sub-bandwidth data by using a range-Doppler algorithm to obtain a band diagram and a plurality of sub-band diagrams of the echo data of the target antenna, wherein the sub-band diagrams correspond to the range-wise sub-bandwidth data one by one.

And the first generation unit is used for generating a difference frequency interference phase diagram based on the plurality of sub-band diagrams of the main antenna echo data and the plurality of sub-band diagrams of the auxiliary antenna echo data.

And the second generation unit is used for generating an original interference phase diagram based on the band diagram of the main antenna echo data and the band diagram of the auxiliary antenna echo data.

According to an embodiment of the present disclosure, a first generation unit includes: the first conjugate processing subunit, the second conjugate processing subunit and the interference processing subunit.

And the first conjugate processing subunit is used for carrying out conjugate processing on the plurality of sub-band diagrams of the echo data of the main antenna to obtain a main difference frequency interference diagram.

And the second conjugation processing subunit is used for carrying out conjugation processing on the plurality of sub-band diagrams of the echo data of the auxiliary antenna to obtain an auxiliary difference frequency interference diagram.

And the interference processing subunit is used for carrying out interference processing on the main difference frequency interference pattern and the auxiliary difference frequency interference pattern to obtain a difference frequency interference phase diagram.

According to an embodiment of the present disclosure, the second generating unit includes: a first alignment subunit and a third conjugate processing subunit.

And the first alignment subunit is used for aligning the band diagram of the echo data of the auxiliary antenna with the band diagram of the echo data of the main antenna based on the distance difference value to obtain an aligned band diagram of the echo data of the auxiliary antenna.

And the third conjugation processing subunit is used for carrying out conjugation processing on the band diagram and the alignment band diagram of the echo data of the main antenna to obtain an original interference phase diagram.

According to an embodiment of the present disclosure, an interference processing subunit includes: a second alignment subunit and a fourth conjugate processing subunit.

And the second alignment subunit is used for aligning the auxiliary difference frequency interference pattern with the main difference frequency interference pattern based on the distance difference value to obtain an aligned difference frequency interference pattern of the auxiliary difference frequency interference pattern.

And the fourth conjugation processing subunit is used for carrying out conjugation processing on the main difference frequency interference pattern and the alignment difference frequency interference pattern to obtain a difference frequency interference phase pattern.

Any of the generation module 610, the determination module 620, and the reconstruction module 630 may be combined in one module to be implemented, or any of the modules may be split into multiple modules, according to embodiments of the present disclosure. Or at least some of the functionality of one or more of the modules may be combined with, and implemented in, at least some of the functionality of other modules. At least one of the generation module 610, the determination module 620, and the reconstruction module 630 may be implemented at least in part as hardware circuitry, such as a Field Programmable Gate Array (FPGA), a Programmable Logic Array (PLA), a system-on-chip, a system-on-a-substrate, a system-on-package, an Application Specific Integrated Circuit (ASIC), or by hardware or firmware, such as any other reasonable way of integrating or packaging the circuitry, or in any one of or a suitable combination of three of software, hardware, and firmware. Or at least one of the generation module 610, the determination module 620 and the reconstruction module 630 may be at least partially implemented as a computer program module which, when executed, may perform the corresponding functions.

As shown in fig. 7, the electronic device according to the embodiment of the present disclosure includes a processor 701 that can perform various appropriate actions and processes according to a program stored in a Read Only Memory (ROM) 702 or a program loaded from a storage section 708 into a Random Access Memory (RAM) 703. The processor 701 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)), or the like. The processor 701 may also include on-board memory for caching purposes. The processor 701 may comprise a single processing unit or a plurality of processing units for performing different actions of the method flows according to embodiments of the disclosure.

In the RAM703, various programs and data required for the operation of the electronic apparatus are stored. The processor 701, the ROM702, and the RAM703 are connected to each other through a bus 704. The processor 701 performs various operations of the method flow according to the embodiments of the present disclosure by executing programs in the ROM702 and/or the RAM 703. Note that the program may be stored in one or more memories other than the ROM702 and the RAM 703. The processor 701 may also perform various operations of the method flow according to embodiments of the present disclosure by executing programs stored in the one or more memories.

According to embodiments of the present disclosure, the electronic device may further include an input/output (I/O) interface 705, the input/output (I/O) interface 705 also being connected to the bus 704. The electronic device may also include one or more of the following components connected to the I/O interface 705: an input section 706 including a keyboard, a mouse, and the like; an output portion 707 including a Cathode Ray Tube (CRT), a Liquid Crystal Display (LCD), and the like, a speaker, and the like; a storage section 708 including a hard disk or the like; and a communication section 709 including a network interface card such as a LAN card, a modem, or the like. The communication section 709 performs communication processing via a network such as the internet. The drive 710 is also connected to the I/O interface 705 as needed. A removable medium 711 such as a magnetic disk, an optical disk, a magneto-optical disk, a semiconductor memory, or the like is mounted on the drive 710 as necessary, so that a computer program read therefrom is mounted into the storage section 708 as necessary.

The present disclosure also provides a computer-readable storage medium that may be embodied in the apparatus/device/system described in the above embodiments; or may exist alone without being assembled into the apparatus/device/system. The computer-readable storage medium carries one or more programs which, when executed, implement methods in accordance with embodiments of the present disclosure.

According to embodiments of the present disclosure, the computer-readable storage medium may be a non-volatile computer-readable storage medium, which may include, for example, but is not limited to: a portable computer diskette, a hard disk, a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In the context of this disclosure, a computer-readable storage medium may be any tangible medium that can contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device. For example, the computer-readable storage medium may include ROM702 and/or RAM703 and/or one or more memories other than ROM702 and RAM703 described above.

Embodiments of the present disclosure also include a computer program product comprising a computer program containing program code for performing the methods shown in the flowcharts. The program code, when executed in a computer system, causes the computer system to perform the methods provided by embodiments of the present disclosure.

The above-described functions defined in the system/apparatus of the embodiments of the present disclosure are performed when the computer program is executed by the processor 701. The systems, apparatus, modules, units, etc. described above may be implemented by computer program modules according to embodiments of the disclosure.

In one embodiment, the computer program may be based on a tangible storage medium such as an optical storage device, a magnetic storage device, or the like. In another embodiment, the computer program may also be transmitted, distributed over a network medium in the form of signals, downloaded and installed via the communication section 709, and/or installed from the removable medium 711. The computer program may include program code that may be transmitted using any appropriate network medium, including but not limited to: wireless, wired, etc., or any suitable combination of the foregoing.

In such an embodiment, the computer program may be downloaded and installed from a network via the communication portion 709, and/or installed from the removable medium 711. The above-described functions defined in the system of the embodiments of the present disclosure are performed when the computer program is executed by the processor 701. The systems, devices, apparatus, modules, units, etc. described above may be implemented by computer program modules according to embodiments of the disclosure.

According to embodiments of the present disclosure, program code for performing computer programs provided by embodiments of the present disclosure may be written in any combination of one or more programming languages, and in particular, such computer programs may be implemented in high-level procedural and/or object-oriented programming languages, and/or assembly/machine languages. Programming languages include, but are not limited to, such as Java, c++, python, "C" or similar programming languages. The program code may execute entirely on the user's computing device, partly on the user's device, partly on a remote computing device, or entirely on the remote computing device or server. In the case of remote computing devices, the remote computing device may be connected to the user computing device through any kind of network, including a Local Area Network (LAN) or a Wide Area Network (WAN), or may be connected to an external computing device (e.g., connected via the Internet using an Internet service provider).

The flowcharts and block diagrams in the figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods and computer program products according to various embodiments of the present disclosure. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). It should also be noted that, in some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams or flowchart illustration, and combinations of blocks in the block diagrams or flowchart illustration, can be implemented by special purpose hardware-based systems which perform the specified functions or acts, or combinations of special purpose hardware and computer instructions.

Those skilled in the art will appreciate that the features recited in the various embodiments of the disclosure and/or in the claims may be provided in a variety of combinations and/or combinations, even if such combinations or combinations are not explicitly recited in the disclosure. In particular, the features recited in the various embodiments of the present disclosure and/or the claims may be variously combined and/or combined without departing from the spirit and teachings of the present disclosure. All such combinations and/or combinations fall within the scope of the present disclosure.

The embodiments of the present disclosure are described above. These examples are for illustrative purposes only and are not intended to limit the scope of the present disclosure. Although the embodiments are described above separately, this does not mean that the measures in the embodiments cannot be used advantageously in combination. The scope of the disclosure is defined by the appended claims and equivalents thereof. Various alternatives and modifications can be made by those skilled in the art without departing from the scope of the disclosure, and such alternatives and modifications are intended to fall within the scope of the disclosure.

Claims

1. A digital elevation model reconstruction method based on interference phase diagram comprises the following steps:

Generating an original interference phase diagram and a difference frequency interference phase diagram based on antenna echo data, wherein the antenna echo data are data formed by reflected signals received by a radar system, and the reflected signals are formed by radar signals transmitted by the radar system after being reflected by a target to be detected;

Determining the unwrapping phase of each pixel in the original interference phase map based on a phase difference model and the unwrapping phase of each pixel in the difference frequency interference phase map;

Reconstructing a digital elevation model of the object to be detected based on the unwrapping phase of each pixel in the original interference phase diagram and the two-dimensional coordinates of each pixel.

2. The method of claim 1, wherein reconstructing the digital elevation model of the object to be detected based on the unwrapped phase of each pixel in the original interference phase map and the two-dimensional coordinates of each pixel comprises:

Acquiring the height of each pixel according to the unwrapping phase of each pixel in the original interference phase diagram;

reconstructing the digital elevation model based on the height of each pixel and the two-dimensional coordinates of each pixel.

3. The method of claim 1 or 2, wherein the determining the unwrapping phase for each pixel in the original interferometric phase map based on the phase difference model and the unwrapping phase for each pixel in the difference-frequency interferometric phase map comprises:

calculating the greatest common divisor of the wavelength of the difference frequency interference phase diagram and the wavelength of the original interference phase diagram;

calculating parameters of the difference frequency interference phase map and parameters of the original interference phase map based on the greatest common divisor;

inputting the unwrapping phase of each pixel in the difference frequency interference phase diagram, the original phase of each pixel and the parameters of the difference frequency interference phase diagram to the phase difference model to obtain a first intermediate value of each pixel in the difference frequency interference phase diagram;

Inputting the original phase of each pixel in the original interference phase map and the parameters of the original interference phase map to the phase difference model to obtain a second intermediate value of each pixel in the original interference phase map;

And performing geometric operation by using the first intermediate value of each pixel in the difference frequency interference phase diagram and the second intermediate value of each pixel in the original interference phase diagram to obtain the unwrapping phase of each pixel in the original interference phase diagram.

4. The method of claim 1, wherein the antenna echo data comprises primary antenna echo data and secondary antenna echo data, the primary antenna echo data being obtained by a primary radar system, the secondary antenna echo data being obtained by a secondary radar system;

the generating an original interference phase map and a difference frequency interference phase map based on the antenna echo data comprises the following steps:

Performing Fourier transform on target antenna echo data to obtain distance bandwidth data, wherein the target antenna echo data is the main antenna echo data or the auxiliary antenna echo data;

Splitting the distance-oriented bandwidth data to obtain a plurality of distance-oriented sub-bandwidth data;

Respectively carrying out imaging processing on the range-wise bandwidth data and each range-wise sub-bandwidth data by using a range-Doppler algorithm to obtain a band diagram and a plurality of sub-band diagrams of the target antenna echo data, wherein the sub-band diagrams are in one-to-one correspondence with the range-wise sub-bandwidth data;

Generating the difference frequency interference phase map based on the plurality of sub-band maps of the main antenna echo data and the plurality of sub-band maps of the auxiliary antenna echo data;

and generating the original interference phase diagram based on the band diagram of the main antenna echo data and the band diagram of the auxiliary antenna echo data.

5. The method of claim 4, wherein the generating the difference frequency interference phase map based on the plurality of sub-band maps of the primary antenna echo data and the plurality of sub-band maps of the secondary antenna echo data comprises:

performing conjugate processing on a plurality of sub-band diagrams of the main antenna echo data to obtain a main difference frequency interference diagram;

Performing conjugate processing on a plurality of sub-band diagrams of the echo data of the auxiliary antenna to obtain an auxiliary difference frequency interference diagram;

and carrying out interference processing on the main difference frequency interference pattern and the auxiliary difference frequency interference pattern to obtain the difference frequency interference phase diagram.

6. The method of claim 4, wherein the generating the original interference phase map based on the band map of the primary antenna echo data and the band map of the secondary antenna echo data comprises:

Aligning the band diagram of the secondary antenna echo data with the band diagram of the primary antenna echo data based on the distance difference value to obtain an aligned band diagram of the secondary antenna echo data;

performing conjugate processing on the band diagram of the main antenna echo data and the alignment band diagram to obtain the original interference phase diagram;

The distance difference value is a distance difference value between a first distance and a second distance, the first distance is a distance between the target to be detected and the main radar system, and the second distance is a distance between the target to be detected and the auxiliary radar system.

7. The method according to claim 5 or 6, wherein the performing interference processing on the primary difference frequency interferogram and the secondary difference frequency interferogram to obtain the difference frequency interference phase map includes:

based on the distance difference, aligning the auxiliary difference frequency interference pattern with the main difference frequency interference pattern to obtain an aligned difference frequency interference pattern of the auxiliary difference frequency interference pattern;

And performing conjugate processing on the main difference frequency interference pattern and the alignment difference frequency interference pattern to obtain the difference frequency interference phase diagram.

8. A digital elevation model reconstruction device based on an interference phase map, the device comprising:

The system comprises a generation module, a detection module and a detection module, wherein the generation module is used for generating an original interference phase diagram and a difference frequency interference phase diagram based on antenna echo data, wherein the antenna echo data are data formed by a reflection signal received by a radar system, and the reflection signal is formed by the reflection of a radar signal transmitted by the radar system by a target to be detected;

the determining module is used for determining the unwrapping phase of each pixel in the original interference phase diagram based on the phase difference model and the unwrapping phase of each pixel in the difference frequency interference phase diagram;

and the reconstruction module is used for reconstructing the digital elevation model of the object to be detected based on the unwrapping phase of each pixel in the original interference phase diagram and the two-dimensional coordinates of each pixel.

9. An electronic device, comprising:

one or more processors;

a memory for storing one or more computer programs,

Characterized in that the one or more processors execute the one or more computer programs to implement the steps of the method according to any one of claims 1 to 7.

10. A computer-readable storage medium, on which a computer program or instructions is stored, characterized in that the computer program or instructions, when executed by a processor, implement the steps of the method according to any one of claims 1-7.