CN109613533B - Double-station microwave staring correlated imaging method and device, storage medium and electronic equipment - Google Patents

Double-station microwave staring correlated imaging method and device, storage medium and electronic equipment Download PDF

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CN109613533B
CN109613533B CN201910021089.2A CN201910021089A CN109613533B CN 109613533 B CN109613533 B CN 109613533B CN 201910021089 A CN201910021089 A CN 201910021089A CN 109613533 B CN109613533 B CN 109613533B
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imaging
radiation field
target area
grid
station
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CN109613533A (en
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郭圆月
陈卫东
袁博
王东进
蒋铮
夏瑞
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University of Science and Technology of China USTC
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/88—Radar or analogous systems specially adapted for specific applications
    • G01S13/89—Radar or analogous systems specially adapted for specific applications for mapping or imaging
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
    • G01S7/41—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00 using analysis of echo signal for target characterisation; Target signature; Target cross-section

Abstract

The invention provides a double-station microwave staring correlated imaging method, which comprises the steps of determining the specific position of a target area, arranging a first transmitting station and a second transmitting station above the target area, synchronously transmitting frequency hopping pulse signals to an imaging plane where the target area is located by the transmitting stations in a preset pulse period, superposing the signals transmitted by the first transmitting station and the second transmitting station on the imaging plane of the target area to form a grid random radiation field, receiving echo signals scattered in the grid radiation field, and performing correlated imaging processing on the echo signals and the random radiation field to obtain an imaging image of the target area; by applying the method provided by the invention, when the microwave correlation imaging processing is carried out on the imaged target area, the 3dB main lobe width of the space correlation function of the random radiation field in each grid in the formed grid radiation field is unchanged, thereby ensuring that a high-quality correlation imaging image is obtained during the long-distance correlation imaging.

Description

Double-station microwave staring correlated imaging method and device, storage medium and electronic equipment
Technical Field
The invention relates to the technical field of radar imaging, in particular to a double-station microwave staring correlated imaging method and device, a storage medium and electronic equipment.
Background
With the rapid development of the current scientific technology, the radar technology is more and more mature. The radar is applied to the field of detecting whether an object has a crack or not and ranging until the radar is applied to acquiring a panoramic image of a specific area, and the technology of imaging by using the radar is called radar imaging technology; the existing mature radar imaging technologies include synthetic aperture radar imaging technology, inverse synthetic aperture radar imaging technology, microwave correlation imaging technology and the like.
The radar imaging technology is applied to various fields in the society, for example, when a marine ship sails, whether reef or iceberg exists on the sea bottom of a course or not is determined by applying the radar imaging technology, so that the safety of the sailing process is ensured; by using a radar imaging technology, a landform image at deep sea can be obtained, so that an inexhaustible deep sea landform image can be obtained, and research data of geological researchers is enriched; the radar imaging technology can also be applied to the aspect of meteorological monitoring, the radar can work all weather, the weather of a specific area is monitored in real time, and a meteorological chart is generated, so that weather researchers can know the meteorological conditions of the specific area in real time.
In the existing radar imaging technology, the microwave correlation imaging technology is most widely applied, the imaging quality of the microwave correlation imaging technology is higher than that of the synthetic aperture radar imaging technology, the inverse synthetic aperture radar imaging technology and the like, but the imaging quality of the microwave correlation imaging technology is greatly influenced by the distance, and the imaging quality is not good under the remote condition.
Disclosure of Invention
The invention aims to solve the technical problem of providing a double-station microwave staring correlated imaging method, which can be used for remotely detecting a target area to be imaged, so that better radiation field randomness is ensured to be obtained in the target area during remote detection, and the obtained correlated imaging picture has higher resolution.
The invention also provides a double-station microwave staring correlated imaging device which is used for ensuring the realization and the application of the method in practice.
A dual-station microwave gaze-correlated imaging method, comprising:
determining a target area to be imaged, and respectively arranging a first transmitting station and a second transmitting station above the target area according to the position of the target area;
triggering a first emission source in the first emission station and a second emission source in the second emission station, and synchronously emitting frequency hopping pulse signals to an imaging plane where the target area is located in a preset pulse period to obtain a first radiation field and a second radiation field which are perpendicular to each other in the imaging plane; the first emission source and the second emission source are respectively composed of a plurality of random radiation units, and a transmission antenna is arranged in each random radiation unit and is used for transmitting frequency hopping pulse signals;
determining a superposed radiation field formed by the first radiation field and the second radiation field at the target area as a grid radiation field of a frequency grid-shaped field type, and determining a random radiation field of each grid center point in the grid radiation field;
calling a preset receiver, receiving an echo signal which is scattered in the target area and corresponds to the grid radiation field, and determining a scattered echo of the target area according to the echo signal;
and calling a preset correlation imaging algorithm, and performing correlation imaging processing on the scattered echoes and the random radiation fields of the grid central points to obtain a correlation imaging graph corresponding to the target area.
The method described above, optionally, the determining a target region to be imaged includes:
when an imaging request for an imaging target is received, acquiring position information of the imaging target contained in the imaging request;
and determining a target area for imaging the imaging target in the established space coordinate system according to the position information of the imaging target.
Optionally, in the method, the setting a first transmitting station and a second transmitting station above the target area according to the position of the target area includes:
determining a first center point at a first height above the target region and a second center point at a second height above the target region; the oblique downward visual angle of the first central point relative to a target position point in the target area is equal to the oblique downward visual angle of the second central point relative to the target position point;
determining a position of the first transmitting station according to the first central point, and determining a position of the second transmitting station according to the second central point; and the projection of the connecting line of the first central point and the target position point is vertical to the projection of the connecting line of the second central point and the target position point.
Optionally, the triggering a first emission source in the first emission station and a second emission source in the second emission station, and synchronously emitting a frequency hopping pulse signal to an imaging plane where the target region is located in a preset pulse period to obtain a first radiation field and a second radiation field that are perpendicular to each other in the imaging plane includes:
triggering a first emission source in the first emission station, emitting a frequency hopping pulse signal to an imaging plane where the target area is located in the preset pulse period, generating a plurality of radiation field strips perpendicular to the Y direction in the established space coordinate system, and determining the first radiation field according to the plurality of radiation field strips perpendicular to the Y direction;
and simultaneously triggering a second emission source in the second emission station, transmitting a frequency hopping pulse signal to the imaging plane where the target area is located in the preset pulse period, generating a plurality of radiation field strips vertical to the X direction in the established space coordinate system, and determining the second radiation field according to the plurality of radiation field strips vertical to the X direction.
Optionally, the method includes that the triggering a first emission source in the first emission station to emit a frequency hopping pulse signal in the imaging plane where the target area is located within the preset pulse period, and the triggering a second emission source in the second emission station to emit a frequency hopping pulse signal in the imaging plane where the target area is located within the preset pulse period, and includes:
setting the same high-precision time and frequency references for a plurality of random radiating elements in the first emission source and a plurality of random radiating elements in the second emission source;
and triggering a plurality of random radiation units in the first emission source and a plurality of random radiation units in the second emission source based on the high-precision time and frequency reference, and synchronously transmitting intra-pulse and inter-pulse frequency hopping pulse signals to an imaging plane where the target area is located in the preset pulse time period.
The foregoing method, optionally, the determining a random radiation field at a central point of each grid in the grid radiation field, includes:
dividing the target area into grids which are arranged in order and have consistent sizes through the grid radiation field, and determining position vectors of central points of the grids corresponding to the target area;
and calling a preset radiation field formula, calculating a random radiation field for the position vector of each grid central point, calling a preset correction radiation field formula, and correcting the random radiation field of each grid central point to obtain the corrected random radiation field of each grid central point.
Optionally, the method for obtaining the associated imaging corresponding to the target region by invoking a preset associated imaging algorithm and performing associated imaging processing on the scattered echoes and the random radiation fields at the central points of the grids includes:
sampling the scattered echo and the random radiation field in space and time, calling a preset discretization imaging equation, and generating an imaging equation matrix vector related to the random radiation field and the scattered echo;
and obtaining a target scattering coefficient according to the imaging equation matrix vector, determining an operator for correlated imaging, substituting the target scattering coefficient and the operator into a preset spatial correlation imaging algorithm for calculation, and obtaining a correlated imaging image of the target area.
A dual-station microwave gaze-correlated imaging apparatus, comprising:
the device comprises a setting unit, a first imaging unit and a second imaging unit, wherein the setting unit is used for determining a target area to be imaged and respectively setting a first transmitting station and a second transmitting station above the target area according to the position of the target area;
the triggering unit is used for triggering a first emission source in the first emission station and a second emission source in the second emission station, synchronously emitting frequency hopping pulse signals to an imaging plane where the target area is located in a preset pulse period, and obtaining a first radiation field and a second radiation field which are perpendicular to each other in the imaging plane; the first emission source and the second emission source are respectively composed of a plurality of random radiation units, and a transmission antenna is arranged in each random radiation unit and is used for transmitting frequency hopping pulse signals;
a determining unit, configured to determine a superimposed radiation field formed by the first radiation field and the second radiation field at the target area as a grid radiation field of a frequency grid pattern, and determine a random radiation field at a central point of each grid in the grid radiation field;
the receiving unit is used for calling a preset receiver, receiving an echo signal which is scattered in the target area and corresponds to the grid radiation field, and determining a scattered echo of the target area according to the echo signal;
and the imaging unit is used for calling a preset associated imaging algorithm, and performing associated imaging processing on the scattered echoes and the random radiation fields of the grid central points to obtain an associated imaging graph corresponding to the target area.
A storage medium comprising a stored program, wherein the program, when executed, controls an apparatus on which the storage medium resides to perform a two-station microwave gaze-associated imaging method as described above.
An electronic device comprising a memory, and one or more instructions stored in the memory and configured to be executed by one or more processors to perform the method of dual-station microwave gaze-correlated imaging described above.
Compared with the prior art, the invention has the following advantages:
the invention provides a double-station microwave staring correlated imaging method, which comprises the following steps: determining a target area to be imaged, and respectively arranging a first transmitting station and a second transmitting station above the target area according to the position of the target area; triggering a first emission source in a first emission station and a second emission source in a second emission station, and synchronously emitting frequency hopping pulse signals to an imaging plane where a target area is located in a preset pulse period to obtain a first radiation field and a second radiation field which are perpendicular to each other in the imaging plane; determining a superposed radiation field formed by the first radiation field and the second radiation field in the target area as a grid radiation field with a frequency grid pattern, and determining a random radiation field of each grid center point in the grid radiation field; calling a preset receiver, receiving an echo signal which is scattered in the target area and corresponds to the grid radiation field, and determining a scattered echo of the target area according to the echo signal; and calling a preset correlation imaging algorithm, and performing correlation imaging processing on the scattered echoes and the random radiation fields of the central points of the grids to obtain a correlation imaging graph corresponding to the target area. In the method provided by the invention, the 3dB main lobe width of the spatial correlation function of the random radiation field in each grid in the grid radiation field is not increased along with the increase of the target imaging distance, so that better radiation field randomness is obtained in the target area during long-distance correlation imaging, and a high-quality correlation imaging image is obtained.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.
Fig. 1 is a flowchart of a method of a two-station microwave staring imaging method according to an embodiment of the present invention;
FIG. 2 is an exemplary diagram of a two-station microwave gaze imaging method provided by embodiments of the present invention;
fig. 3 is a diagram illustrating a method flow of a dual-station microwave staring imaging method according to another embodiment of the present invention;
fig. 4 is a diagram illustrating a method flow of a dual-station microwave staring imaging method according to another embodiment of the present invention;
fig. 5 is a diagram illustrating a method flow of a dual-station microwave staring imaging method according to another embodiment of the present invention;
fig. 6 is a flowchart illustrating a method flow of a dual-station microwave staring imaging method according to another embodiment of the present invention;
fig. 7 is a flowchart illustrating a method flow of a dual-station microwave staring imaging method according to an embodiment of the present invention;
FIG. 8 is a diagram illustrating an exemplary structure of a dual-station microwave staring imaging device according to an embodiment of the present invention;
fig. 9 is a schematic structural diagram of an electronic device according to an embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In this application, relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions, and the terms "comprises", "comprising", or any other variation thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
The invention is operational with numerous general purpose or special purpose computing device environments or configurations. For example: personal computers, server computers, hand-held or portable devices, tablet-type devices, multi-processor devices, including any device or apparatus that uses or is equipped with radar, and the like.
The embodiment of the invention provides a double-station microwave staring correlated imaging method, which can be applied to various system platforms, such as a radar system, wherein an execution main body of the method can be a computer terminal or a computer server, and a flow chart of the method is shown in fig. 1 and specifically comprises the following steps:
s101: determining a target area to be imaged, and setting a first transmitting station and a second transmitting station according to the position of the target area;
in the method provided by the embodiment of the invention, the execution body computer terminal or the computer server analyzes the received instruction by receiving the instruction, so as to determine the target area to be imaged, determines the specific position of the target area to be imaged according to the analysis of the instruction, calculates the specific position of the target area by a preset algorithm, obtains the reasonable positions of the first transmitting station and the second transmitting station above the target area, and adjusts the first transmitting station and the second transmitting station to the reasonable positions according to the calculated reasonable positions.
It should be noted that the first transmitting station and the second transmitting station are both radars or radar systems.
S102: triggering a first emission source in the first emission station and a second emission source in the second emission station, and synchronously emitting frequency hopping pulse signals to an imaging plane where the target area is located in a preset pulse period to obtain a first radiation field and a second radiation field which are perpendicular to each other in the imaging plane; the first emission source and the second emission source are respectively composed of a plurality of random radiation units, and a transmission antenna is arranged in each random radiation unit and is used for transmitting frequency hopping pulse signals;
in the method provided by the embodiment of the present invention, after the positions of the first transmitting station and the second transmitting station are adjusted, preset transmitting sources in the first transmitting station and the second transmitting station are triggered, the transmitting sources synchronously transmit frequency hopping pulse signals to an imaging plane where a target area is located within a preset pulse period, a first radiation field and a second radiation field in a frequency strip shape are formed in the imaging plane, and frequency strips forming the first radiation field and the second radiation field are perpendicular to each other; the frequency hopping pulse signal is transmitted by a transmitting antenna in a preset random radiation unit, the transmitting source is a random radiation antenna array consisting of a plurality of random radiation units, and the projections of connecting lines of the centers of the random radiation antenna arrays of the two transmitting stations and the center of an imaging area on an imaging plane are mutually vertical through the reasonable layout of the positions of the first transmitting station and the second transmitting station.
S103: determining a superposed radiation field formed by the first radiation field and the second radiation field at the target area as a grid radiation field of a frequency grid-shaped field type, and determining a random radiation field of each grid center point in the grid radiation field;
in the method provided by the embodiment of the invention, when the first emission source and the second emission source simultaneously emit pulse signals to the imaging plane where the target region is located, a first radiation field formed by the pulse signals emitted by the first emission source and a second radiation field formed by the pulse signals emitted by the second emission source are simultaneously superposed on the imaging plane where the target region is located to form a grid radiation field of a frequency grid-shaped field type, the target region is divided into grids with consistent sizes and ordered arrangement through the grid radiation field, and a random radiation field at the center point of each grid is determined, wherein the width of a 3dB main lobe of a spatial correlation function of the random radiation field in each grid is not increased along with the increase of the imaging distance.
S104: calling a preset receiver, receiving an echo signal which is scattered in the target area and corresponds to the grid radiation field, and determining a scattered echo of the target area according to the echo signal;
in the method provided by the embodiment of the invention, a preset receiver is called to receive the echo signals scattered by each object to the pulse signals in the target area covered by the grid radiation field, a preset scattering echo formula is called to calculate the echo signals, and the scattering echoes in the whole target area received by the antenna of the receiver are obtained.
S105: calling a preset correlation imaging algorithm, and performing correlation imaging processing on the scattered echoes and the random radiation fields of the grid central points to obtain a correlation imaging graph corresponding to the target area;
in the method provided by the embodiment of the invention, a preset correlation imaging algorithm is called, correlation imaging processing is carried out on the random radiation field of each grid central point obtained by calculation and the scattering echo in the target area covered by the grid radiation field, so as to obtain a high-quality imaging image of the target area, the width of a 3dB main lobe of a spatial correlation function of the random radiation field in each grid is not increased along with the increase of an imaging distance, and therefore, the quality of the imaging image of the target area is not reduced due to the long distance between a transmitting station and the target area.
In the method provided by the embodiment of the invention, a specific position of a target area is determined, a first transmitting station and a second transmitting station are respectively arranged above the target area, a frequency hopping pulse signal is synchronously transmitted to an imaging plane where the target area is located by triggering the first transmitting station and the second transmitting station within a preset pulse period, a grid radiation field of a frequency grid-shaped field type is formed by superposing the formed first radiation field and the second radiation field on the target area, and a random radiation field of each grid central point in the grid radiation field is determined; calling a preset receiver, receiving an echo signal which is scattered by the target area and corresponds to the grid radiation field, determining a scattered echo of the target area according to the echo signal, calling a preset correlation imaging algorithm, and performing correlation imaging processing on the scattered echo and random radiation fields of all grid central points to obtain a correlation imaging graph corresponding to the target area; in the method provided by the embodiment of the invention, the 3dB main lobe width of the spatial correlation function of the random radiation field in each grid is not increased along with the increase of the imaging distance, and a long-distance and high-quality target imaging image can be obtained by applying the method provided by the embodiment of the invention.
In the method provided in the embodiment of the present invention, when adjusting the positions of the first transmitting station and the second transmitting station, the specific position of the target area needs to be determined, and the process of determining the specific position of the target area is as follows:
when an imaging request for an imaging target is received, acquiring position information of the imaging target contained in the imaging request;
in the method provided by the embodiment of the present invention, when the execution subject receives the imaging request for the imaging target, the execution subject parses the request to obtain specific location information of the target location included in the request, where the specific location information may be a coordinate location of the imaging target and a size of an area of the imaging target, and the specific location of the target area is determined according to the coordinate location and the size of the area of the imaging target.
Determining a target area for imaging the imaging target in the established space coordinate system according to the position information of the imaging target;
in the method provided in the embodiment of the present invention, a spatial coordinate system is established on an imaging plane of the target area according to the specific position information of the imaging target, the target area of the imaging target is determined according to the established spatial coordinate system, and the spatial positions of the first transmitting station and the second transmitting station are reasonably arranged according to the target area, as specifically shown in fig. 2;
on the established space coordinate system, (x, y, z) represents a rectangular coordinate system, the origin is O, the rectangular coordinate system is positioned at the center of the target area imaging scene, and the first transmitting station and the second transmitting stationTwo launching stations are respectively positioned on two static or quasi-static aerial platforms, the heights are respectively H1 and H2, the H1 is a first height above the target area, and the H2 is a second height above the target area; the oblique downward viewing angle of the first central point relative to the target position point in the target area and the oblique downward viewing angle of the second central point relative to the target position point in the target area are both alpha, that is, the oblique downward viewing angles of the first transmitting station and the second transmitting station to the target imaging area are both alpha; the coordinates of the first central point and the second central point are respectively (0-H)1tanα,H1) And (-H)2tanα,0,H2) The first central point and the second central point are central points of random radiation antenna arrays of a first transmitting station and a second transmitting station respectively, and transmitting array aperture surfaces of the first transmitting station and the second transmitting station are D respectively1And D2(ii) a The projections of the connecting lines of the center of the random radiation array of the first transmitting station, the center of the random radiation array of the second transmitting station and the center of the target imaging area on the imaging plane are mutually vertical;
the target imaging area, that is, the coverage area of the beams transmitted by the first transmitting station and the second transmitting station, is G. D1Comprising a transmitting antenna I1A, D2Comprising a transmitting antenna I2A receiving antenna is positioned on the transmitting port surface D1Or D2And (4) the following steps. The coordinates of the ith transmitting antenna and the receiving antenna of the nth transmitting array are respectively used
Figure BDA0001940768800000091
And
Figure BDA0001940768800000092
and (4) showing.
In the method provided by the embodiment of the invention, in the actual microwave correlation imaging, the scattering characteristics such as reflection geometry, masking, coherent scintillation and the like are closely related to the observation angle. Therefore, in practical applications, the observation angle θ between the first transmitting station and the second transmitting station in the present invention with respect to the target area is often limited to 15 °. According to the geometry, a and theta are related
Figure BDA0001940768800000101
Therefore, in general, α is less than 10 °.
In the method provided by the embodiment of the present invention, a random radiation field is formed by transmitting a pulse signal to the target imaging region, and a specific process of transmitting the pulse signal to the target imaging region is as follows:
triggering a first emission source in the first emission station, emitting a frequency hopping pulse signal to an imaging plane where the target area is located in the preset pulse period, generating a plurality of radiation field strips perpendicular to the Y direction in the established space coordinate system, and determining the first radiation field according to the plurality of radiation field strips perpendicular to the Y direction;
simultaneously, triggering a second emission source in the second emission station, transmitting a frequency hopping pulse signal to the imaging plane where the target area is located in the preset pulse period, generating a plurality of radiation field strips vertical to the X direction in the established space coordinate system, and determining the second radiation field according to the plurality of radiation field strips vertical to the X direction;
in the method provided by the embodiment of the invention, a first transmitting station D1Forming Q radiation field strips vertical to the Y direction on an imaging plane XOY, and forming a first radiation field in a frequency strip shape; second transmitting station D2Forming Q radiation field strips vertical to the X direction on the imaging plane XOY, and forming a second radiation field in a frequency strip shape; radiation fields formed by the two transmitting stations are superposed in a target imaging area, and a grid radiation field of a frequency grid-shaped field type is formed on an imaging plane where the target area is located, as shown in fig. 3 specifically;
in the method provided by the embodiment of the present invention, in order to improve the randomness of the transmitted signals, the signals transmitted by the first transmitting station and the second transmitting station adopt a form of frequency hopping within a pulse and between pulses, so that in a pulse transmission period, a radiation field formed by the signals transmitted by the transmitting stations forms a strip-shaped radiation field perpendicular to the transmission distance in space, and strips at different distances from the transmitting stations are covered by different radiation fields, as specifically shown in fig. 3; the width of the strip-shaped radiation field strip is determined by the intra-pulse frequency hopping interval delta t and the oblique downward viewing angle alpha of the transmitting station to the target imaging area; the transmission signals of the ith transmission unit in the random radiation array in the first transmission station and the second transmission station are as follows:
Figure BDA0001940768800000102
Figure BDA0001940768800000103
wherein T represents time, T represents the pulse period of the transmitted signal, Δ T represents the intra-pulse frequency hopping interval, Q represents the number of intra-pulse frequency hopping, the pulse width is QΔ T, L represents the total number of transmitted pulses, fn,i,l,qThe frequency hopping frequency of the ith array antenna unit of the nth radar station in the qth sub-pulse of the ith pulse is randomly selected within the transmission bandwidth B of the transmitting station, wherein L is 1,2, … L, n is 1or2, I is 1,2, … I1orI2Q is 1,2 … Q; the random frequency hopping used by all antenna elements of the random radiation array in the first transmitting station and the second transmitting station is orthogonal, and the signal waveform diagram of the transmission signal is shown in fig. 4.
In the method provided in the embodiment of the present invention, triggering a first emission source in the first emission station to emit a frequency hopping pulse signal in the imaging plane where the target area is located within the preset pulse period, and triggering a second emission source in the second emission station to emit a frequency hopping pulse signal in the imaging plane where the target area is located within the preset pulse period specifically includes:
setting the same high-precision time and frequency references for a plurality of random radiating elements in the first emission source and a plurality of random radiating elements in the second emission source;
and triggering a plurality of random radiation units in the first emission source and a plurality of random radiation units in the second emission source based on the high-precision time and frequency reference, and synchronously transmitting intra-pulse and inter-pulse frequency hopping pulse signals to an imaging plane where the target area is located in the preset pulse time period.
In the double-station microwave staring correlated imaging method provided by the embodiment of the invention, the first emission source of the first emission station comprises a plurality of random radiation units. The second emission source of the second emission station also includes a plurality of random radiation elements therein. The random radiation units of the first emission source and the second emission source are set with the same high-precision time and frequency reference. And triggering each random radiation unit in the first emission source and the second emission source based on the same high-precision time and frequency reference, and synchronizing the imaging plane where the target area is located in a pulse period to synchronously emit frequency hopping pulse signals in pulses and among pulses. And meanwhile, calling a pulse signal calculation formula, and calculating frequency hopping pulse signals in and among pulses transmitted by each random radiation unit in the first transmission station and the second transmission station to obtain a pulse frequency hopping signal transmitted by each random radiation unit.
In the method provided by the embodiment of the present invention, determining the random radiation field of each grid center point in the grid radiation field specifically includes:
dividing the target area into grids which are arranged in order and have consistent sizes through the grid radiation field, and determining position vectors of central points of the grids corresponding to the target area;
and calling a preset radiation field formula, calculating a random radiation field for the position vector of each grid central point, calling a preset correction radiation field formula, and correcting the random radiation field of each grid central point to obtain the corrected random radiation field of each grid central point.
In the double-station microwave staring correlated imaging method provided by the embodiment of the invention, after the grid radiation field of the frequency grid-shaped pattern is obtained, the target area is divided into a plurality of grids, wherein the grids in the target area are consistent in size and are arranged in order. And determining the position vector of the target area corresponding to the grid central point of each grid through the processor. And calling a radiation field formula, and calculating the position vector of each grid central point to obtain the random radiation field of each grid central point.
In the embodiment of the present invention, the first radiation field and the second radiation field are both strip-shaped field types, the grid radiation field is formed by overlapping the first radiation field and the second radiation field, and discretizes the target imaging region G, and the grid number of the grid radiation field in the target region is determined by the strip number of the first radiation field and the second radiation field. For example, if the number of strips of the first radiation field is P and the number of strips of the second radiation field is Q, the number of grids is M, where: m ═ P × Q. The grid center point m is a position of a center of a qth grid point in a pth row and a qth column in the grid, wherein: m ═ P-1) Q + (Q-1) P +1, M ═ 1,2, … M. Determining a target scattering coefficient for the grid center m as
Figure BDA0001940768800000121
Then the target area is G, an
Figure BDA0001940768800000122
Calculating the position vector of the grid central point m of the current grid corresponding to the target area
Figure BDA0001940768800000123
The formula of the radiation field formed is as follows:
Figure BDA0001940768800000124
the receiver antenna receives the scattered echo in the target region
Figure BDA0001940768800000125
Receiving scattered echo signals scattered in an imaging target area by a receiving antenna of the receiver, and calculating the scattered echo corresponding to the echo signals as follows:
Figure BDA0001940768800000126
wherein the content of the first and second substances,
Figure BDA0001940768800000127
for imaging region grid location vector
Figure BDA0001940768800000128
Phase center position vector relative to receiving antenna
Figure BDA0001940768800000129
The unit vector of the spatial direction of (a),
Figure BDA00019407688000001210
as a function of the receive antenna pattern;
and then calling a corrected radiation field formula to correct the random radiation field at the center of each grid. For example, for the target area position vector corresponding to the grid center point m to the formula of the modified radiation field
Figure BDA0001940768800000131
Correcting the formula of the formed radiation field, which is as follows:
Figure BDA0001940768800000132
said is located at
Figure BDA0001940768800000133
The receiving of the scattering echo in the imaging target area by the receiving antenna of the receiver is simplified as follows:
Figure BDA0001940768800000134
wherein the content of the first and second substances,
Figure BDA0001940768800000135
respectively representing the radiation pattern function and the spatial position vector of the ith transmitting antenna of the transmitting station,
Figure BDA0001940768800000136
as a position vector of the imaging area
Figure BDA0001940768800000137
Ith transmitting antenna center position vector relative to nth transmitting station
Figure BDA0001940768800000138
Unit vector of space direction
Figure BDA0001940768800000139
C is the speed of light;
and finally obtaining the corrected random radiation field of the central point of the grid.
The modified random radiation field spatial correlation function
Figure BDA00019407688000001310
The 3dB width of the main lobe is less than that of the main lobe along any direction
Figure BDA00019407688000001311
And does not increase with increasing imaging distance, indicating that the random radiation field can still maintain good randomness when the region is imaged at a long distance. Spatial correlation function of the modified random radiation field in the imaging region
Figure BDA00019407688000001312
The amplitude normalization is approximately:
Figure BDA00019407688000001313
wherein phii，
Figure BDA00019407688000001314
And phi0，
Figure BDA00019407688000001315
Elevation angle and azimuth angle of the double-station radar random radiation antenna array unit and the receiver antenna under a spherical coordinate respectively, c is light speed,
Figure BDA00019407688000001316
for imaging the area
Figure BDA00019407688000001317
The distance vector of the grid to the surrounding grid,
Figure BDA00019407688000001318
to imaging area arbitrary
Figure BDA00019407688000001319
Grid mesh
Figure BDA00019407688000001320
Moving in any direction
Figure BDA00019407688000001321
Or
Figure BDA00019407688000001322
Then all are provided with
Figure BDA00019407688000001323
That is to say
Figure BDA00019407688000001324
The 3dB width of the main lobe of the function is less than that of the main lobe in any direction
Figure BDA00019407688000001325
So that the width of the main lobe is narrower along all directions and does not follow the imaging distanceAnd varies from one variation to another.
By applying the method provided by the embodiment of the invention, the 3dB main lobe width of the spatial correlation function of the random radiation field in each grid is not increased along with the increase of the imaging distance, and a long-distance and high-quality target imaging image can be obtained by applying the method provided by the embodiment of the invention.
In the method provided by the embodiment of the present invention, a preset correlation imaging algorithm is called to perform correlation imaging processing on the scattered echoes and the random radiation fields of the grid central points, so as to obtain correlation imaging corresponding to the target area, and the method specifically includes:
sampling the scattered echo and the random radiation field in space and time, calling a preset discretization imaging equation, and generating an imaging equation matrix vector related to the random radiation field and the scattered echo;
and obtaining a target scattering coefficient according to the imaging equation matrix vector, determining an operator for correlated imaging, substituting the target scattering coefficient and the operator into a preset spatial correlation imaging algorithm for calculation, and obtaining a correlated imaging image of the target area.
In the two-station microwave staring correlated imaging method provided by the embodiment of the invention, after the scattered echo of the target area is obtained, the scattered echo and the random radiation field are sampled in space and time, and a discretization equation is called to simplify the discretization equation and generate an imaging equation matrix vector related to the random radiation field and the scattered echo, and the specific process comprises the following steps:
the discretization equation is as follows:
Figure BDA0001940768800000141
the imaging equation matrix vector is as follows:
Esca＝Erad·σ；
after an imaging equation matrix vector is generated, a target scattering coefficient can be obtained, an operator for correlation imaging is determined according to the scattering coefficient, and a correlation imaging image of the target area is obtained by substituting the target scattering coefficient and the operator for calculation through a spatial correlation imaging algorithm.
The spatially correlated imaging process may be represented as:
Figure BDA0001940768800000142
it should be noted that, in the following description,
Figure BDA0001940768800000151
different associated imaging algorithms are embodied as different operators for the operators of the associated imaging algorithms. When the next correlation imaging is needed, a direct first-order field intensity correlation algorithm, a pseudo-inverse algorithm, an Orthogonal Matching Pursuit (OMP) algorithm, a Sparse Bayesian Learning (SBL) algorithm and the like can be adopted.
Based on the method provided by the embodiment, the simulation experiment is carried out on the double-station microwave staring imaging method, and the specific simulation experiment content is as follows:
a staring correlated imaging radar system used for simulation works in an X wave band, and transmits a signal transmission mode of frequency hopping in a pulse and between pulses, all random radiation units in a double-station transmitting station and a single-station transmitting station are uniformly arrayed, and specific transmission parameters are shown in table 1. Table 1 shows single and dual station gaze-correlated imaging radar system parameters; the parameters involved are the same in all simulations of this section. In the following simulations, the two transmit stations of the two-station gaze imaging are located at the same height, but the application scenario of the present invention is not so limited.
Figure BDA0001940768800000152
TABLE 1
The imaging distance, the emission pulse width and the intra-pulse beat frequency time interval are set differently in different simulations below, and specific parameters are shown below.
Simulation 1: single-station and double-station radiation field correlation simulation
We performed simulation 1 comparing the radiation field correlation for single and dual station gaze correlated imaging. The system parameters and imaging geometrical configuration parameters of the single-station radar and the double-station radar are shown in the table 1, the transmission signal form of the single-station radar and the double-station radar is shown in the table 2, and the height of a radar platform is 1 km.
Fig. 5 shows the relevant characteristics of the radiation field for single and dual station gaze correlated imaging. When the height of the radar platform is 1km, as can be seen from fig. 5, for the single-station radar, the spatial correlation characteristic of the radiation field is better along the Y direction, and is limited by the transmitting aperture along the X direction, the radiation field of the single-station radar has poor spatial correlation characteristic, a wide main lobe and a high side lobe. For the two-station radar, the main lobe of the radiation field correlation in the X and y directions is narrow, and the higher side lobes are arranged along the X axis and the [1, -1,0] direction.
Simulation 2: single-station and double-station staring imaging simulation
The following simulations were performed for single and dual station radars at different imaging distances. The system parameters and the transmission signal forms of the single-station radar and the double-station radar are compared. The simulation target is shown in the following figure. For evaluation of the imaging results, a normalized recovery error is defined as
Figure BDA0001940768800000161
Where σ represents the scattering coefficient vector of the imaging region,
Figure BDA0001940768800000162
representing the recovered scattering coefficient vector.
And (3) performing inversion on the imaging target under different imaging distances, namely different radar platform heights by simulation, and comparing the target pair recovery results of the single-station radar and the double-station radar. Simulation parameters are shown in tables 2 and 3, wherein the table 2 is system parameters of the single-station radar and the double-station radar, the table 3 is imaging scene parameters of the single-station radar and the double-station radar at different platform heights, and the table 4 is NSME of the single-station recovery image and the double-station recovery image;
Figure BDA0001940768800000163
TABLE 2
Radar platform height Single station Double station
2km Size of imaging area 80m×80m 80m×80m
Imaging grid size 2m×2m 2m×2m
5km Size of imaging area 120m×120m 120m×120m
Imaging grid size 3m×3m 3m×3m
10km Imaging areaDomain size 160m×160m 160m×160m
Imaging grid size 4m×4m 4m×4m
TABLE 3
Figure BDA0001940768800000171
TABLE 4
FIG. 7 shows the image inversion result of the single-station and double-station staring correlated imaging radar at different radar platform heights, and it can be seen from FIG. 7 that the image recovery effect of the double-station radar is far better than that of the single station under the condition that the signal-to-noise ratio is 25 dB. As can also be seen from the NMSE of the recovered image in table 4, the NMSE of the recovered image of the two-station radar is smaller, and the recovery result is better.
Simulation 3: spatial correlation characteristic of radiation field of double-station radar under different imaging distances
Under the conditions of different imaging distances, the heights of the double-station radar platform are respectively 1km and 10km, a table 5 shows the specific parameters of a simulation 3 imaging scene, and the size parameters of the simulation scene are shown in the table 5:
radar platform height 1km Height of radar platform is 10km
Size of radiation field area 40m×40m 200m×200m
Size of space grid 0.5m×0.5m 0.5m×0.5m
TABLE 5
Under different imaging distance conditions, the radiation field correlation characteristics of the two-station radar are shown in fig. 6. As can be seen from fig. 6, the 3dB lobe width of the main lobe of the correlation function of the radiation field of the two-station gaze-correlated imaging does not increase with imaging distance at different imaging distances. While the height of the side lobe does not change with the imaging distance and the width increases with the increase of the imaging distance.
As can be seen from the simulation results, the imaging method of the invention can obtain better random characteristics of the radiation field and realize high-resolution imaging of the target.
In conclusion, the simulation verifies the correctness, realizability and validity of the method provided by the embodiment.
Corresponding to the method described in fig. 1, an embodiment of the present invention further provides a dual-station microwave gaze-related imaging apparatus, which is used for implementing the method in fig. 1 specifically, and the dual-station microwave gaze-related imaging apparatus provided in the embodiment of the present invention may be applied to a computer terminal or various mobile devices, and a schematic structural diagram of the dual-station microwave gaze-related imaging apparatus is shown in fig. 8, and specifically includes:
a setting unit 801, configured to determine a target area to be imaged, and set a first transmitting station and a second transmitting station above the target area according to a position of the target area;
a triggering unit 802, configured to trigger a first emission source in the first emission station and a second emission source in the second emission station, and synchronously emit a frequency hopping pulse signal to an imaging plane where the target area is located within a preset pulse period, so as to obtain a first radiation field and a second radiation field that are perpendicular to each other in the imaging plane; the first emission source and the second emission source are respectively composed of a plurality of random radiation units, and a transmission antenna is arranged in each random radiation unit and is used for transmitting frequency hopping pulse signals;
a determining unit 803, configured to determine a superimposed radiation field formed by the first radiation field and the second radiation field at the target area as a grid radiation field with a frequency grid pattern, and determine a random radiation field at each grid center point in the grid radiation field;
a receiving unit 804, configured to invoke a preset receiver, receive an echo signal scattered by the target region and corresponding to the grid radiation field, and determine a scattered echo of the target region according to the echo signal;
and the imaging unit 805 is configured to invoke a preset correlation imaging algorithm, perform correlation imaging processing on the scattered echoes and the random radiation fields at the grid central points, and obtain a correlation imaging map corresponding to the target area.
In the apparatus provided in the embodiment of the present invention, a target area to be imaged is predetermined, a setting unit sets a first transmitting station and a second transmitting station above the target area according to a position of the target area, a triggering unit triggers a first transmitting source of the first transmitting station and a second transmitting source of the second transmitting station, and within a preset pulse period, a frequency hopping pulse signal is synchronously transmitted to an imaging plane where the target area is located, so as to obtain a first radiation field and a second radiation field perpendicular to each other in the imaging plane. The first emission source and the second emission source are both composed of a plurality of random radiation units, and the random radiation units are provided with emission antennas for emitting frequency hopping pulse signals. According to the frequency hopping pulse signal, a superposed radiation field formed by superposing a first radiation field and a second radiation field is formed in the target area, the determination unit determines that the superposed radiation field is a grid radiation field with a frequency grid pattern, and determines a random radiation field of each grid central point in the grid radiation field. When the target area scatters the echo signal corresponding to the grid radiation field, the receiving unit calls a preset receiver to receive the echo signal, and determines the scattering echo of the target area according to the echo signal. And finally, calling a preset associated imaging algorithm by the imaging unit, and performing associated imaging processing on the scattered echoes and the random radiation fields of the grid central points to obtain an associated imaging graph corresponding to the target area.
In the apparatus provided in the embodiment of the present invention, based on the foregoing scheme, the setting unit 801 is configured to:
when an imaging request for an imaging target is received, acquiring position information of the imaging target contained in the imaging request;
and determining a target area for imaging the imaging target in the established space coordinate system according to the position information of the imaging target.
In the apparatus provided in the embodiment of the present invention, based on the foregoing scheme, the setting unit 801 is configured to:
determining a first center point at a first height above the target region and a second center point at a second height above the target region; the oblique downward visual angle of the first central point relative to a target position point in the target area is equal to the oblique downward visual angle of the second central point relative to the target position point;
determining a position of the first transmitting station according to the first central point, and determining a position of the second transmitting station according to the second central point; and the projection of the connecting line of the first central point and the target position point is vertical to the projection of the connecting line of the second central point and the target position point.
In the apparatus provided in the embodiment of the present invention, based on the foregoing scheme, the triggering unit 802 is configured to:
triggering a first emission source in the first emission station, emitting a frequency hopping pulse signal to an imaging plane where the target area is located in the preset pulse period, generating a plurality of radiation field strips perpendicular to the Y direction in the established space coordinate system, and determining the first radiation field according to the plurality of radiation field strips perpendicular to the Y direction;
and simultaneously triggering a second emission source in the second emission station, transmitting a frequency hopping pulse signal to the imaging plane where the target area is located in the preset pulse period, generating a plurality of radiation field strips vertical to the X direction in the established space coordinate system, and determining the second radiation field according to the plurality of radiation field strips vertical to the X direction.
In the apparatus provided in the embodiment of the present invention, based on the foregoing scheme, the triggering unit 802 is configured to:
setting the same high-precision time and frequency references for a plurality of random radiating elements in the first emission source and a plurality of random radiating elements in the second emission source;
and triggering a plurality of random radiation units in the first emission source and a plurality of random radiation units in the second emission source based on the high-precision time and frequency reference, and synchronously transmitting intra-pulse and inter-pulse frequency hopping pulse signals to an imaging plane where the target area is located in the preset pulse time period.
In the apparatus provided in the embodiment of the present invention, based on the foregoing scheme, the determining unit 803 is configured to:
dividing the target area into grids which are arranged in order and have consistent sizes through the grid radiation field, and determining position vectors of central points of the grids corresponding to the target area;
and calling a preset radiation field formula, calculating a random radiation field for the position vector of each grid central point, calling a preset correction radiation field formula, and correcting the random radiation field of each grid central point to obtain the corrected random radiation field of each grid central point.
In the apparatus provided in the embodiment of the present invention, based on the foregoing scheme, the imaging unit 805 is configured to:
sampling the scattered echo and the random radiation field in space and time, calling a preset discretization imaging equation, and generating an imaging equation matrix vector related to the random radiation field and the scattered echo;
and obtaining a target scattering coefficient according to the imaging equation matrix vector, determining an operator for correlated imaging, substituting the target scattering coefficient and the operator into a preset spatial correlation imaging algorithm for calculation, and obtaining a correlated imaging image of the target area.
The embodiment of the invention also provides a storage medium, which comprises stored instructions, wherein when the instructions are executed, the equipment where the storage medium is located is controlled to execute the following double-station microwave staring correlated imaging method:
determining a target area to be imaged, and respectively arranging a first transmitting station and a second transmitting station above the target area according to the position of the target area;
triggering a first emission source in the first emission station and a second emission source in the second emission station, and synchronously emitting frequency hopping pulse signals to an imaging plane where the target area is located in a preset pulse period to obtain a first radiation field and a second radiation field which are perpendicular to each other in the imaging plane; the first emission source and the second emission source are respectively composed of a plurality of random radiation units, and a transmission antenna is arranged in each random radiation unit and is used for transmitting frequency hopping pulse signals;
determining a superposed radiation field formed by the first radiation field and the second radiation field at the target area as a grid radiation field of a frequency grid-shaped field type, and determining a random radiation field of each grid center point in the grid radiation field;
calling a preset receiver, receiving an echo signal which is scattered in the target area and corresponds to the grid radiation field, and determining a scattered echo of the target area according to the echo signal;
and calling a preset correlation imaging algorithm, and performing correlation imaging processing on the scattered echoes and the random radiation fields of the grid central points to obtain a correlation imaging graph corresponding to the target area.
The method described above, optionally, the determining a target region to be imaged includes:
when an imaging request for an imaging target is received, acquiring position information of the imaging target contained in the imaging request;
and determining a target area for imaging the imaging target in the established space coordinate system according to the position information of the imaging target.
In the foregoing method, optionally, the setting a first transmitting station and a second transmitting station above the target area according to the position of the target area includes:
determining a first center point at a first height above the target region and a second center point at a second height above the target region; the oblique downward visual angle of the first central point relative to a target position point in the target area is equal to the oblique downward visual angle of the second central point relative to the target position point;
determining a position of the first transmitting station according to the first central point, and determining a position of the second transmitting station according to the second central point; and the projection of the connecting line of the first central point and the target position point is vertical to the projection of the connecting line of the second central point and the target position point.
Optionally, the triggering a first emission source in the first emission station and a second emission source in the second emission station, and synchronously emitting a frequency hopping pulse signal to an imaging plane where the target region is located in a preset pulse period to obtain a first radiation field and a second radiation field that are perpendicular to each other in the imaging plane includes:
triggering a first emission source in the first emission station, emitting a frequency hopping pulse signal to an imaging plane where the target area is located in the preset pulse period, generating a plurality of radiation field strips perpendicular to the Y direction in the established space coordinate system, and determining the first radiation field according to the plurality of radiation field strips perpendicular to the Y direction;
and simultaneously triggering a second emission source in the second emission station, transmitting a frequency hopping pulse signal to the imaging plane where the target area is located in the preset pulse period, generating a plurality of radiation field strips vertical to the X direction in the established space coordinate system, and determining the second radiation field according to the plurality of radiation field strips vertical to the X direction.
Optionally, the method includes that the triggering a first emission source in the first emission station to emit a frequency hopping pulse signal in the imaging plane where the target area is located within the preset pulse period, and the triggering a second emission source in the second emission station to emit a frequency hopping pulse signal in the imaging plane where the target area is located within the preset pulse period, and includes:
setting the same high-precision time and frequency references for a plurality of random radiating elements in the first emission source and a plurality of random radiating elements in the second emission source;
and triggering a plurality of random radiation units in the first emission source and a plurality of random radiation units in the second emission source based on the high-precision time and frequency reference, and synchronously transmitting intra-pulse and inter-pulse frequency hopping pulse signals to an imaging plane where the target area is located in the preset pulse time period.
The foregoing method, optionally, the determining a random radiation field at a central point of each grid in the grid radiation field, includes:
dividing the target area into grids which are arranged in order and have consistent sizes through the grid radiation field, and determining position vectors of central points of the grids corresponding to the target area;
and calling a preset radiation field formula, calculating a random radiation field for the position vector of each grid central point, calling a preset correction radiation field formula, and correcting the random radiation field of each grid central point to obtain the corrected random radiation field of each grid central point.
Optionally, the method for obtaining the associated imaging corresponding to the target region by invoking a preset associated imaging algorithm and performing associated imaging processing on the scattered echoes and the random radiation fields at the central points of the grids includes:
sampling the scattered echo and the random radiation field in space and time, calling a preset discretization imaging equation, and generating an imaging equation matrix vector related to the random radiation field and the scattered echo;
and obtaining a target scattering coefficient according to the imaging equation matrix vector, determining an operator for correlated imaging, substituting the target scattering coefficient and the operator into a preset spatial correlation imaging algorithm for calculation, and obtaining a correlated imaging image of the target area.
An embodiment of the present invention further provides an electronic device, a schematic structural diagram of which is shown in fig. 9, specifically including a memory 901 and one or more instructions 902, where the one or more instructions 902 are stored in the memory 901, and are configured to be executed by one or more processors 903 to perform the following operations according to the one or more instructions 902:
determining a target area to be imaged, and respectively arranging a first transmitting station and a second transmitting station above the target area according to the position of the target area;
triggering a first emission source in the first emission station and a second emission source in the second emission station, and synchronously emitting frequency hopping pulse signals to an imaging plane where the target area is located in a preset pulse period to obtain a first radiation field and a second radiation field which are perpendicular to each other in the imaging plane; the first emission source and the second emission source are respectively composed of a plurality of random radiation units, and a transmission antenna is arranged in each random radiation unit and is used for transmitting frequency hopping pulse signals;
determining a superposed radiation field formed by the first radiation field and the second radiation field at the target area as a grid radiation field of a frequency grid-shaped field type, and determining a random radiation field of each grid center point in the grid radiation field;
calling a preset receiver, receiving an echo signal which is scattered in the target area and corresponds to the grid radiation field, and determining a scattered echo of the target area according to the echo signal;
and calling a preset correlation imaging algorithm, and performing correlation imaging processing on the scattered echoes and the random radiation fields of the grid central points to obtain a correlation imaging graph corresponding to the target area.
The embodiments in the present specification are described in a progressive manner, and the same and similar parts among the embodiments are referred to each other, and each embodiment focuses on the differences from the other embodiments. In particular, the system or system embodiments are substantially similar to the method embodiments and therefore are described in a relatively simple manner, and reference may be made to some of the descriptions of the method embodiments for related points. The above-described system and system embodiments are only illustrative, wherein the units described as separate parts may or may not be physically separate, and the parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment. One of ordinary skill in the art can understand and implement it without inventive effort.
Those of skill would further appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or combinations of both, and that the various illustrative components and steps have been described above generally in terms of their functionality in order to clearly illustrate this interchangeability of hardware and software. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (9)

1. A method of dual-station microwave gaze-correlated imaging, comprising:
determining a target area to be imaged, and respectively arranging a first transmitting station and a second transmitting station above the target area according to the position of the target area;
triggering a first emission source in the first emission station and a second emission source in the second emission station, and synchronously emitting frequency hopping pulse signals to an imaging plane where the target area is located in a preset pulse period to obtain a first radiation field and a second radiation field which are perpendicular to each other in the imaging plane; the first emission source and the second emission source are respectively composed of a plurality of random radiation units, and a transmission antenna is arranged in each random radiation unit and is used for transmitting frequency hopping pulse signals;
determining a superposed radiation field formed by the first radiation field and the second radiation field at the target area as a grid radiation field of a frequency grid-shaped field type, and determining a random radiation field of each grid center point in the grid radiation field;
calling a preset receiver, receiving an echo signal which is scattered in the target area and corresponds to the grid radiation field, and determining a scattered echo of the target area according to the echo signal;
calling a preset correlation imaging algorithm, and performing correlation imaging processing on the scattered echoes and the random radiation fields of the grid central points to obtain a correlation imaging graph corresponding to the target area;
the calling a preset correlation imaging algorithm to perform correlation imaging processing on the scattered echoes and the random radiation fields of the grid central points to obtain correlation imaging corresponding to the target area includes:
sampling the scattered echo and the random radiation field in space and time, calling a preset discretization imaging equation, and generating an imaging equation matrix vector related to the random radiation field and the scattered echo;
and obtaining a target scattering coefficient according to the imaging equation matrix vector, determining an operator for correlated imaging, substituting the target scattering coefficient and the operator into a preset spatial correlation imaging algorithm for calculation, and obtaining a correlated imaging image of the target area.
2. The method of claim 1, wherein the determining a target region to be imaged comprises:
when an imaging request for an imaging target is received, acquiring position information of the imaging target contained in the imaging request;
and determining a target area for imaging the imaging target in the established space coordinate system according to the position information of the imaging target.
3. The method of claim 1or2, wherein the respectively positioning of the first and second transmitting stations above the target area according to the position of the target area comprises:
determining a first center point at a first height above the target region and a second center point at a second height above the target region; the oblique downward visual angle of the first central point relative to a target position point in the target area is equal to the oblique downward visual angle of the second central point relative to the target position point;
determining a position of the first transmitting station according to the first central point, and determining a position of the second transmitting station according to the second central point; and the projection of the connecting line of the first central point and the target position point is vertical to the projection of the connecting line of the second central point and the target position point.
4. The method of claim 3, wherein the triggering a first emission source in the first emission station and a second emission source in the second emission station to synchronously emit frequency hopping pulse signals to an imaging plane where the target region is located within a preset pulse period, so as to obtain a first radiation field and a second radiation field perpendicular to each other in the imaging plane, comprises:
triggering a first emission source in the first emission station, emitting a frequency hopping pulse signal to an imaging plane where the target area is located in the preset pulse period, generating a plurality of radiation field strips perpendicular to the Y direction in the established space coordinate system, and determining the first radiation field according to the plurality of radiation field strips perpendicular to the Y direction;
and simultaneously triggering a second emission source in the second emission station, transmitting a frequency hopping pulse signal to the imaging plane where the target area is located in the preset pulse period, generating a plurality of radiation field strips vertical to the X direction in the established space coordinate system, and determining the second radiation field according to the plurality of radiation field strips vertical to the X direction.
5. The method according to claim 1or 4, wherein the triggering a first emission source in the first emission station to emit a frequency-hopping pulse signal in the imaging plane of the target area within the predetermined pulse period, and triggering a second emission source in the second emission station to emit a frequency-hopping pulse signal in the imaging plane of the target area within the predetermined pulse period comprises:
setting the same high-precision time and frequency references for a plurality of random radiating elements in the first emission source and a plurality of random radiating elements in the second emission source;
and triggering a plurality of random radiation units in the first emission source and a plurality of random radiation units in the second emission source based on the high-precision time and frequency reference, and synchronously transmitting intra-pulse and inter-pulse frequency hopping pulse signals to an imaging plane where the target area is located in the preset pulse time period.
6. The method of claim 1, wherein determining the random radiation field for each grid center point in the grid radiation field comprises:
dividing the target area into grids which are arranged in order and have consistent sizes through the grid radiation field, and determining position vectors of central points of the grids corresponding to the target area;
and calling a preset radiation field formula, calculating a random radiation field for the position vector of each grid central point, calling a preset correction radiation field formula, and correcting the random radiation field of each grid central point to obtain the corrected random radiation field of each grid central point.
7. A dual-station microwave gaze-correlated imaging apparatus, comprising:
the device comprises a setting unit, a first imaging unit and a second imaging unit, wherein the setting unit is used for determining a target area to be imaged and respectively setting a first transmitting station and a second transmitting station above the target area according to the position of the target area;
the triggering unit is used for triggering a first emission source in the first emission station and a second emission source in the second emission station, synchronously emitting frequency hopping pulse signals to an imaging plane where the target area is located in a preset pulse period, and obtaining a first radiation field and a second radiation field which are perpendicular to each other in the imaging plane; the first emission source and the second emission source are respectively composed of a plurality of random radiation units, and a transmission antenna is arranged in each random radiation unit and is used for transmitting frequency hopping pulse signals;
a determining unit, configured to determine a superimposed radiation field formed by the first radiation field and the second radiation field at the target area as a grid radiation field of a frequency grid pattern, and determine a random radiation field at a central point of each grid in the grid radiation field;
the receiving unit is used for calling a preset receiver, receiving an echo signal which is scattered in the target area and corresponds to the grid radiation field, and determining a scattered echo of the target area according to the echo signal;
the imaging unit is configured to invoke a preset associated imaging algorithm, perform associated imaging processing on the scattered echo and the random radiation field at each grid central point, and obtain an associated imaging map corresponding to the target area, where the invoking of the preset associated imaging algorithm performs associated imaging processing on the scattered echo and the random radiation field at each grid central point, and obtains an associated imaging corresponding to the target area, and specifically includes: sampling the scattered echo and the random radiation field in space and time, calling a preset discretization imaging equation, and generating an imaging equation matrix vector related to the random radiation field and the scattered echo; and obtaining a target scattering coefficient according to the imaging equation matrix vector, determining an operator for correlated imaging, substituting the target scattering coefficient and the operator into a preset spatial correlation imaging algorithm for calculation, and obtaining a correlated imaging image of the target area.
8. A storage medium comprising a stored program, wherein the program when executed controls an apparatus on which the storage medium resides to perform a method of two-station microwave gaze-correlated imaging according to any of claims 1 to 6.
9. An electronic device comprising a memory and one or more instructions, wherein the one or more instructions are stored in the memory and configured to be executed by one or more processors to perform the method of two-station microwave gaze-correlated imaging according to any of claims 1-6.
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