A design method, device and electronic equipment of a bistatic ISAR imaging configuration

Abstract

The application discloses a design method, device and electronic equipment of a bistatic ISAR imaging configuration, and is used for realizing the design of a bistatic ISAR imaging configuration under the resolution constraint. The design method comprises the following steps: determining the position information of a group of transmitting stations and receiving stations; establishing a coordinate system according to the position information and the target position, and constructing an echo model under the coordinate system; performing approximate expansion processing on the bistatic angle introduced in the bistatic ISAR imaging process, and constructing a corresponding mathematical model; transmitting radar signals by using the transmitting stations; receiving digital echo signals by using the receiving stations; calculating a first constraint condition of high-resolution imaging and a second constraint condition of the bistatic angle change rate according to a preset bandwidth and in combination with the echo model, the digital echo signals and the mathematical model; and deploying the spatial positions of the transmitting stations and the receiving stations according to the first constraint condition of the high-resolution imaging and the second constraint condition of the bistatic angle change rate.

Description

Technical Field

[0001] This application relates to the field of bistatic radar imaging, and more particularly to a design method, apparatus and electronic device for a bistatic ISAR imaging configuration. Background Technology

[0002] Currently, in the single-base station imaging method, when the target moves towards the single-base radar along the line of sight, the angle of the target relative to the line of sight of the single-base radar is almost zero. This causes the azimuth resolution of the single-base radar to drop rapidly, making it impossible to obtain two-dimensional detailed information of the target.

[0003] To address these issues, researchers have proposed a novel base station radar—Bistatic Inverse Synthetic Aperture Radar (Bi-ISAR). This Bi-ISAR utilizes the spatial diversity advantages of transmitting and receiving stations through a separate spatial deployment, creating different observation perspectives on the target and thus achieving high-resolution two-dimensional imaging of targets with arbitrary flight trajectories.

[0004] Currently, numerous research institutions both domestically and internationally have conducted extensive research on bistatic synthetic aperture radar (Bi-SAR) technology, obtaining experimental data processing results for bistatic SAR imaging, which has greatly promoted the development of bistatic imaging technology. Building upon this foundation, many research institutions both domestically and internationally have also studied Bi-ISAR imaging technology, achieving some progress in simulation and experimental data acquisition.

[0005] However, relatively speaking, current domestic research on bistatic ISAR imaging technology is still focused on the imaging technique itself, with limited research on the boundary conditions between different bistatic ISAR imaging configurations and resolution. As the resolution of bistatic ISAR imaging increases, the first-order rate of change of the bistatic angle becomes increasingly important for the design of bistatic ISAR imaging configurations. To quantitatively analyze the relationship between these two factors, it is essential to conduct research on the design of bistatic ISAR imaging configurations under resolution constraints. Summary of the Invention

[0006] To address the shortcomings of the existing technologies, the purpose of this application is to propose a design method for bistatic ISAR imaging configuration based on resolution constraints. This method constructs a corresponding bistatic ISAR imaging echo vector model and a rotation approximation model for bistatic ISAR imaging, qualitatively describes the entire process of bistatic ISAR imaging using mathematical formulas, and finally achieves the design of bistatic ISAR imaging configuration under resolution constraints by deriving the boundary of the bistatic angle change rate under distance constraints.

[0007] This application discloses a design method, apparatus, and electronic device for bistatic ISAR imaging configurations, used to realize the design of bistatic ISAR imaging configurations under resolution constraints.

[0008] The first aspect of this application provides a design method for a dual-base ISAR imaging configuration, including:

[0009] Determine the location information of a set of transmitting and receiving stations;

[0010] Establish a coordinate system based on the location information and target location, and construct an echo model within the coordinate system;

[0011] The bistatic angles introduced during bistatic ISAR imaging are approximated and expanded, and a corresponding mathematical model is constructed.

[0012] Use the transmitting station to transmit radar signals;

[0013] Use a receiving station to receive digital echo signals;

[0014] Based on the preset bandwidth and combined with the echo model, digital echo signal and mathematical model, calculate the first constraint condition for high-resolution imaging and the second constraint condition for the bibasal angle change rate.

[0015] The spatial locations of the transmitter and receiver stations are determined based on the first constraint condition of high-resolution imaging and the second constraint condition of the bibasal angle change rate.

[0016] Optionally, after receiving the digital echo signal using the receiving station, and before calculating the first constraint condition for high-resolution imaging and the second constraint condition for the bistatic angle change rate based on the preset bandwidth and in combination with the echo model, the digital echo signal, and the mathematical model, the design method further includes:

[0017] The space-time-frequency information between the transmitting station and the receiving station is synchronized. The space-time-frequency information includes space, time, and frequency.

[0018] Optionally, after receiving the digital echo signal using the receiving station, and before calculating the first constraint condition for high-resolution imaging and the second constraint condition for the bistatic angle change rate based on the preset bandwidth and in combination with the echo model, the digital echo signal, and the mathematical model, the design method further includes:

[0019] The direct wave signal in the digital echo signal entering the receiving station is suppressed.

[0020] Optionally, after receiving the digital echo signal using the receiving station, and before calculating the first constraint condition for high-resolution imaging and the second constraint condition for the bistatic angle change rate based on the preset bandwidth and in combination with the echo model, the digital echo signal, and the mathematical model, the design method further includes:

[0021] When the target moves, the digital echo signal entering the receiving station is compensated based on the distance change caused by the target's translation.

[0022] Optionally, radar signals may be transmitted using a transmitting station, including:

[0023] The baseband signal generated by the frequency synthesizer is transmitted through the upconversion link and the transmitting antenna unit to radiate the radar signal to the preset area using the transmitting station.

[0024] Optionally, a receiving station may be used to receive digital echo signals, including:

[0025] The radio frequency signal received by the receiving antenna unit of the receiving station is converted into an intermediate frequency signal;

[0026] The intermediate frequency signal is converted into a digital echo signal.

[0027] A second aspect of this application provides a design apparatus for a dual-base ISAR imaging configuration, comprising:

[0028] The determination unit is used to determine the location information of a set of transmitting and receiving stations;

[0029] The first building unit is used to establish a coordinate system based on the location information and the target location, and to build an echo model in the coordinate system;

[0030] The second building unit is used to approximate the expansion of the bistatic angles introduced in the bistatic ISAR imaging process and to build the corresponding mathematical model.

[0031] Transmission unit, used to transmit radar signals using a transmission station;

[0032] The receiving unit is used to receive digital echo signals using a receiving station;

[0033] The calculation unit is used to calculate the first constraint condition and the second constraint condition of the bibasic angle change rate for high-resolution imaging based on the preset bandwidth and in combination with the echo model, digital echo signal and mathematical model.

[0034] The deployment unit is used to deploy the spatial positions of the transmitter and receiver stations according to the first constraint condition of high-resolution imaging and the second constraint condition of the bistatic angle change rate.

[0035] Optionally, after the receiving unit and before the computing unit, the design device further includes:

[0036] The synchronization unit is used to synchronize the space-time-frequency information between the transmitting station and the receiving station. The space-time-frequency information includes space, time, and frequency.

[0037] Optionally, after the receiving unit and before the computing unit, the design device further includes:

[0038] The suppression unit is used to suppress the direct wave signal in the digital echo signal entering the receiving station.

[0039] Optionally, after the receiving unit and before the computing unit, the design device further includes:

[0040] The compensation unit is used to compensate the digital echo signal entering the receiving station based on the distance change caused by the target's translation.

[0041] Optional, the transmitting unit includes:

[0042] The baseband signal generated by the frequency synthesizer is transmitted through the upconversion link and the transmitting antenna unit to radiate the radar signal to the preset area using the transmitting station.

[0043] Optionally, the receiving unit includes:

[0044] The radio frequency signal received by the receiving antenna unit of the receiving station is converted into an intermediate frequency signal;

[0045] The intermediate frequency signal is converted into a digital echo signal.

[0046] A third aspect of this application provides an electronic device, comprising:

[0047] Processor, memory, input / output units, and bus;

[0048] The processor is connected to memory, input / output units, and a bus;

[0049] The memory stores the program, and the processor calls the program to execute the first aspect and any optional design method of the first aspect.

[0050] The fourth aspect of this application provides a computer-readable storage medium on which a program is stored, which, when executed on a computer, performs the first aspect and any optional design method of the first aspect.

[0051] As can be seen from the above technical solutions, the embodiments of this application have the following advantages:

[0052] In this application, the location information of a set of transmitting and receiving stations is first determined, and the specific locations of these transmitting and receiving stations are transformed into the ECEF coordinate system to form location information. Next, a coordinate system is established based on the location information and the target location, that is, the target location is also transformed into the ECEF coordinate system, and an echo model is constructed in this coordinate system. The echo model can perform high-precision processing on the received waveform to generate usable information. Then, the bistatic angles introduced in the bistatic ISAR imaging process are approximated and expanded, and a corresponding mathematical model is constructed. Next, the transmitting station transmits radar signals, and the receiving station receives digital echo signals. Based on a preset bandwidth and combined with the echo model, digital echo signals, and mathematical model, the first constraint condition for high-resolution imaging and the second constraint condition for the bistatic angle change rate are calculated. Finally, the spatial locations of the transmitting and receiving stations are deployed according to the first constraint condition for high-resolution imaging and the second constraint condition for the bistatic angle change rate.

[0053] The beneficial effects of this application are as follows: First, this invention creatively proposes a resolution-constrained bistatic ISAR imaging configuration design method. With the given resolution constraints, the bistatic angle and bistatic angle change rate boundary conditions under different observation configurations can be quickly and quantitatively calculated, and the spatial positions of the transmitting station and receiving station can be reasonably deployed to optimize the imaging performance of the entire system.

[0054] Secondly, the method of the present invention does not require hardware modifications to existing radar equipment during its implementation, and has good prospects for engineering applications.

[0055] This application constructs an echo model and a mathematical model corresponding to the bistatic angle, and then calculates the first constraint condition for high-resolution imaging and the second constraint condition for the bistatic angle change rate. This allows for the rapid identification of the maximum boundary value of the bistatic angle change rate under a given range resolution and bistatic angle. Based on the maximum boundary value, the positions of the transmitting and receiving stations can be reasonably designed, and the bistatic ISAR imaging configuration can be optimized. This ensures that the optimal bistatic ISAR imaging configuration satisfies both the range resolution requirements and the maximum boundary condition for the bistatic angle change rate, thereby achieving the design of a bistatic ISAR imaging configuration for the target under resolution constraints. Attached Figure Description

[0056] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0057] Figure 1 This is a flowchart illustrating the design method of the dual-base ISAR imaging configuration in this application.

[0058] Figure 2 This is another flowchart illustrating the design method for the dual-base ISAR imaging configuration of this application;

[0059] Figure 3 This is a graph showing the maximum permissible boundary value of the rate of change of bistatic angle for signals of different bandwidths under different bistatic angle conditions in this application.

[0060] Figure 4 This is a graph showing the maximum allowable boundary value of the rate of change of bistatic angle under different bistatic angle conditions in a 1m resolution scene according to this application;

[0061] Figure 5 This is a graph showing the maximum allowable boundary value of the rate of change of bistatic angle under different bistatic angle conditions in a 0.5m resolution scene according to this application;

[0062] Figure 6 This is a graph showing the maximum allowable boundary value of the rate of change of bistatic angle under different bistatic angle conditions in a 0.3m resolution scene according to this application;

[0063] Figure 7 This is a graph showing the maximum allowable boundary value of the rate of change of bistatic angle under different bistatic angle conditions in a 0.1m resolution scene according to this application;

[0064] Figure 8 This is a graph showing the maximum allowable boundary value of the rate of change of bistatic angle under different bistatic angle conditions in a 0.05m resolution scene according to this application;

[0065] Figure 9 This is a schematic diagram of the design device for the dual-base ISAR imaging configuration of this application.

[0066] Figure 10 This is another structural schematic diagram of the design device for the dual-base ISAR imaging configuration of this application;

[0067] Figure 11 This is a schematic diagram of one embodiment of the electronic device of this application. Detailed Implementation

[0068] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of this application with unnecessary detail.

[0069] It should be understood that, when used in this application specification and the appended claims, the term "comprising" indicates the presence of the described features, integrals, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or a collection thereof.

[0070] It should also be understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0071] As used in this application specification and the appended claims, the term "if" may be interpreted, depending on the context, as "when," "once," "in response to determination," or "in response to detection." Similarly, the phrase "if determined" or "if detected [the described condition or event]" may be interpreted, depending on the context, as meaning "once determined," "in response to determination," "once detected [the described condition or event]," or "in response to detection [the described condition or event]."

[0072] Furthermore, in the description of this application and the appended claims, the terms "first," "second," "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0073] References to "one embodiment" or "some embodiments" as described in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0074] In existing technologies, in the imaging method of a single base station, when a target moves towards the single base station radar along the line of sight, the angle of the target relative to the line of sight of the single base station radar is almost zero. This causes the azimuth resolution of the single base station radar to drop rapidly, making it impossible to obtain two-dimensional detailed information of the target.

[0075] To address these issues, researchers have proposed a novel base station radar—Bistatic Inverse Synthetic Aperture Radar (Bi-ISAR). This Bi-ISAR utilizes the spatial diversity advantages of transmitting and receiving stations through a separate spatial deployment, creating different observation perspectives on the target and thus achieving high-resolution two-dimensional imaging of targets with arbitrary flight trajectories.

[0076] Currently, numerous research institutions both domestically and internationally have conducted extensive research on bistatic synthetic aperture radar (Bi-SAR) technology, obtaining experimental data processing results for bistatic SAR imaging, which has greatly promoted the development of bistatic imaging technology. Building upon this foundation, many research institutions both domestically and internationally have also studied Bi-ISAR imaging technology, achieving some progress in simulation and experimental data acquisition.

[0077] However, relatively speaking, current domestic research on bistatic ISAR imaging technology is still focused on the imaging technique itself, with limited research on the boundary conditions between different bistatic ISAR imaging configurations and resolution. As the resolution of bistatic ISAR imaging increases, the first-order rate of change of the bistatic angle becomes increasingly important for the design of bistatic ISAR imaging configurations. To quantitatively analyze the relationship between these two factors, it is essential to conduct research on the design of bistatic ISAR imaging configurations under resolution constraints.

[0078] Based on this, this application discloses a design method, apparatus and electronic device for bistatic ISAR imaging configuration, which is used to realize the design of bistatic ISAR imaging configuration under resolution constraints.

[0079] The technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0080] The method described in this application can be applied to servers, devices, terminals, or other devices with logical processing capabilities; therefore, this application does not limit its application. For ease of description, the following description uses a terminal as the executing entity.

[0081] Please see Figure 1 This application provides an embodiment of a design method for a dual-base ISAR imaging configuration, comprising:

[0082] 101. Determine the location information of a set of transmitting and receiving stations;

[0083] In this embodiment, the position coordinates of the transmitting station and the receiving station are determined and transformed into the ECEF coordinate system to generate position information.

[0084] The following example illustrates this:

[0085] Assume the longitude, latitude, and altitude coordinates of the launch station are (B T ,L T H T If so, the launch station location can be transformed into the ECEF coordinate system. The transformation formula is as follows:

[0086]

[0087] Where e is the Earth's eccentricity (B T ,L T H T These represent the latitude, longitude, and altitude values ​​of the launch station, respectively. Let be the radius of curvature in the ramidal plane of the launch station, and 'a' be a preset coefficient. This allows us to obtain the launch station's location information P. T .

[0088] Similarly, assuming the longitude, latitude, and altitude coordinates of the receiving station are (B R ,L R H R If so, the launch station location can be transformed into the ECEF coordinate system. The transformation formula is as follows:

[0089]

[0090] Where e is the Earth's eccentricity (B R ,L R H R These represent the latitude, longitude, and altitude values ​​of the launch station, respectively. Let be the radius of curvature in the maxima plane of the receiving station, and 'a' be a preset coefficient. The position P of the transmitting station can then be obtained. R .

[0091] 102. Establish a coordinate system based on the location information and target location, and construct an echo model within the coordinate system;

[0092] The terminal establishes a coordinate system based on the location information of the transmitting and receiving stations and the target location (the location of the target imaging object), and constructs an echo model in this coordinate system.

[0093] Assuming the transmitting station radar transmits a linear frequency modulated signal, the specific expression is s. t (τ) is shown in the following formula:

[0094]

[0095] in

[0096] Where τ is the distance-fast time, f c T is the carrier frequency of the radar signal. P denoted as pulse width; μ is the modulation frequency of the signal.

[0097] The emitted electromagnetic wave propagates through a bistatic configuration, and the received echo signal s r (τ,t m It can be described as:

[0098]

[0099] Where σ is the scattering coefficient of the target, c represents the speed of light, and t m =mPRT (m = 0, 1, 2, ...) represents the azimuth time slow, t m For time, R Bi (t m ) = R TPm (t m )+R RPm (t m R is the sum of the instantaneous slant distances from the transmitting station to the target and from the receiving station to the target. Bi (t m The instantaneous launch slant range R from the launch station to the target. TPm (t m The instantaneous receiving slant range R from the receiving station to the target. RPm (t m These can be expressed as:

[0100] R TPm (t m ) = R TOm (t m )+i T *Q

[0101] R RPm (t m ) = R ROm (t m )+i R *Q

[0102] Where R TOm (t m ) represents t m The distance R from the launch station to the target's center of mass at any given time. ROm (t m ) represents t m The distance from the receiving station to the target's center of mass at any given time, i T i represents the unit vector representing the line-of-sight direction from the launch station to the target's centroid.R Let Q be the unit vector representing the line of sight from the receiving station to the target's centroid, and let Q be the vector of any point on the target relative to the target's centroid, where Q = (x... p ,y p ,z p ) T ,() T This indicates a transpose operation, at which point we can obtain the instantaneous slant distance of any point on the target:

[0103] R Bi (t m ) = R TOm (t m )+i T (t m )*Q+R ROm (t m )+i T (t m )*Q

[0104] =2R O (t m )+2K(t m )*Q*i ME (t m )

[0105] in Indicates the t-th m The sum of the instantaneous translational components of the transmitting and receiving stations from the target's center of mass at any given moment, β(t) m )=∠(i T (t m ),i R (t m )) represents the t-th m Instantaneous bibasic angles at any moment Indicates the t-th m The cosine value of the bibasic angles at instantaneous moment. Indicates the t-th m The unit vector of the time-equivalent monostatic radar.

[0106] The echo signal can now be further described as follows:

[0107]

[0108] Where G(t) m )=Q*i ME (t m ), indicating the t-th m The scalar value at time.

[0109] 103. Approximately expand the bistatic angles introduced in the bistatic ISAR imaging process and construct the corresponding mathematical model;

[0110] The terminal approximates the bistatic angles introduced during bistatic ISAR imaging and constructs a corresponding mathematical model.

[0111] Further research on the t-th m The cosine value of the instantaneous bibasic angle K(t) m By performing a first-order Taylor series expansion and approximation, we obtain the following formula:

[0112] K(t m )≈K0+K1*t m

[0113] Among them, the following limitations apply:

[0114]

[0115] in

[0116] Let the instantaneous rotation angle θ(t) caused by the target's rotation be described as:

[0117] θ(t m )=θ0+Ωt m

[0118] Where θ0 represents the initial angle, and Ω is the angular velocity. For ease of analysis, we assume that time θ0 is chosen as the starting time of the analysis. For ease of analysis, the t-th... m scalar value G(t) at time t m It can be described as:

[0119] G(t m )=y p cos(Ωt m )+x p sin(Ωt m )

[0120] Based on the above expansion, the rotation approximation model for bistatic ISAR imaging can be further obtained as follows:

[0121] K(t m )G(t m )=K0y p +(K0x p +K1y p )t m +K1x p Ω*(t m ) 2

[0122] 104. Use a transmitting station to transmit radar signals;

[0123] 105. Use a receiving station to receive digital echo signals;

[0124] The sequence number is sent and received through the transmitting and receiving stations to obtain the target information.

[0125] 106. Based on the preset bandwidth and combined with the echo model, digital echo signal and mathematical model, calculate the first constraint condition and the second constraint condition of the bibasal angle change rate for high-resolution imaging.

[0126] Before calculating the constraints, direct wave suppression and translational compensation are required. After direct wave suppression and translational compensation, the echo signal is pulse-compressed in the range dimension. The echo signal at this point can be described as follows:

[0127]

[0128] in, It is the convolution factor along the fast time dimension τ, where δ() is the Dirac function, δ r Indicates distance migration, and This represents the ideal result after distance pulse compression, and θ(t m ) represents the phase information after distance pulse compression, and

[0129] To meet the requirements of high-resolution imaging, the scattering points on the target should avoid moving across distance cells as much as possible. Therefore, after compensation, δ r Generally, it needs to meet the following requirements. The demand, when the coherent processing interval (CPI) T s When the value is small, the target's turning angle is relatively small, and the influence of higher-order phases can be ignored. Therefore, the corresponding constraint conditions can be described as follows:

[0130]

[0131] By simplifying and solving the above equation along the equivalent rotation axis of the target, we can obtain the constraint condition for the rate of change of the bibasic angle as follows:

[0132]

[0133] 107. Deploy the spatial positions of the transmitting and receiving stations based on the first constraint condition of high-resolution imaging and the second constraint condition of the bibasal angle change rate.

[0134] Based on the system's required distance resolution (first constraint) and the second constraint of biradial angle change rate, determine whether the current positions of the transmitting and receiving stations meet the requirements. If they do, output the spatial coordinates of the transmitting and receiving stations. If they do not meet the requirements, search for a new set of transmitting and receiving station positions until a set that meets the conditions is found.

[0135] In this application, the location information of a set of transmitting and receiving stations is first determined, and the specific locations of these transmitting and receiving stations are transformed into the ECEF coordinate system to form location information. Next, a coordinate system is established based on the location information and the target location, that is, the target location is also transformed into the ECEF coordinate system, and an echo model is constructed in this coordinate system. The echo model can perform high-precision processing on the received waveform to generate usable information. Then, the bistatic angles introduced in the bistatic ISAR imaging process are approximated and expanded, and a corresponding mathematical model is constructed. Next, the transmitting station transmits radar signals, and the receiving station receives digital echo signals. Based on a preset bandwidth and combined with the echo model, digital echo signals, and mathematical model, the first constraint condition for high-resolution imaging and the second constraint condition for the bistatic angle change rate are calculated. Finally, the spatial locations of the transmitting and receiving stations are deployed according to the first constraint condition for high-resolution imaging and the second constraint condition for the bistatic angle change rate.

[0136] By constructing the echo model and the mathematical model corresponding to the bistatic angle, and then calculating the first constraint condition for high-resolution imaging and the second constraint condition for the bistatic angle change rate, the maximum boundary value of the bistatic angle change rate under a given range resolution and bistatic angle can be quickly found. Based on the maximum boundary value, the positions of the transmitting and receiving stations can be reasonably designed to optimize the bistatic ISAR imaging configuration. This ensures that the optimal bistatic ISAR imaging configuration satisfies both the range resolution requirements and the maximum boundary condition for the bistatic angle change rate, thereby realizing the design of the bistatic ISAR imaging configuration for the target under resolution constraints.

[0137] Please see Figure 2 This application provides another embodiment of a design method for a dual-base ISAR imaging configuration, comprising:

[0138] 201. Determine the location information of a set of transmitting and receiving stations;

[0139] 202. Establish a coordinate system based on the location information and target location, and construct an echo model within the coordinate system;

[0140] 203. Approximately expand the bistatic angles introduced in the bistatic ISAR imaging process and construct the corresponding mathematical model;

[0141] In this embodiment, steps 201 to 203 are similar to steps 101 to 103 described above, and will not be repeated here.

[0142] 204. The baseband signal generated by the frequency synthesizer is transmitted to the preset area via the upconversion link and the transmitting antenna unit using the transmitting station;

[0143] In this embodiment, the terminal transmits the baseband signal generated by the frequency synthesizer (the baseband signal here can be a linear frequency modulation signal, a nonlinear frequency modulation signal, a coded signal, etc., but this embodiment mainly uses a linear frequency modulation signal for description) through an up-conversion link, and then radiates the signal to the target airspace of interest (the airspace here can be the air area within the atmosphere or the space area outside the atmosphere) through the transmitting antenna unit.

[0144] 205. Convert the radio frequency signal received by the receiving antenna unit of the receiving station into an intermediate frequency signal;

[0145] 206. Convert the intermediate frequency signal into a digital echo signal;

[0146] In this embodiment, the terminal converts the radio frequency signal received by the receiving antenna unit into an intermediate frequency signal through a down-conversion link, and then converts it into a digital echo signal through digital down-conversion and digital acquisition.

[0147] 207. Synchronize the space-time-frequency information between the transmitting station and the receiving station. The space-time-frequency information includes space, time, and frequency.

[0148] The space-time-frequency synchronization module, on the one hand, aligns the beam pointing areas of the transmitting station and the receiving station in the same spatial location, and on the other hand, sets the carrier frequency center frequency fc of the transmitting station. T and the center frequency fc of the carrier frequency of the receiving station R Maintaining consistency means satisfying the following constraints:

[0149] fc = fc T =fc R

[0150] 208. Suppress the direct wave signal in the digital echo signal entering the receiving station;

[0151] The direct wave suppression module mainly receives the direct wave signal s through an omnidirectional direct wave antenna. d (τ,t m Then, a time-domain adaptive filtering algorithm is used to eliminate the direct wave signal from the echo signal. The specific implementation method is as follows:

[0152] s' r (τ,t m ) = s r (τ,t m )-α*s d (τ,t m )

[0153] Where s' r (τ,t m ) represents the echo signal after direct wave suppression, and α represents the coefficient of adaptive filtering.

[0154] 209. When the target is in translational motion, the digital echo signal entering the receiving station is compensated based on the distance change caused by the target's translational motion.

[0155] The sum of the distances R between the centroids of the launching station and the receiving station is R. O (t m The first version can be given through narrowband measurement, in which case the translational compensation factor H1(τ,t) is constructed. m )for:

[0156]

[0157] 210. Based on the preset bandwidth and in combination with the echo model, digital echo signal and mathematical model, calculate the first constraint condition for high-resolution imaging and the second constraint condition for the bibasal angle change rate.

[0158] 211. Deploy the spatial positions of the transmitting and receiving stations based on the first constraint condition of high-resolution imaging and the second constraint condition of the bibasal angle change rate.

[0159] In this embodiment, steps 210 to 211 are similar to steps 106 to 107 described above, and will not be repeated here.

[0160] In this application, the location information of a set of transmitting and receiving stations is first determined, and the specific locations of these transmitting and receiving stations are transformed into the ECEF coordinate system to form location information. Next, a coordinate system is established based on the location information and the target location, that is, the target location is also transformed into the ECEF coordinate system, and an echo model is constructed in the coordinate system. The echo model can perform high-precision processing on the received waveform to generate usable information. Then, the bistatic angles introduced in the bistatic ISAR imaging process are approximated and expanded, and the corresponding mathematical model is constructed. Next, the baseband signal generated by the frequency synthesizer is radiated to the preset area by the transmitting station via the upconversion link and the transmitting antenna unit, and the radio frequency signal received by the receiving antenna unit of the receiving station is converted into an intermediate frequency signal, and the intermediate frequency signal is converted into a digital echo signal.

[0161] The system synchronizes the space-time-frequency information between the transmitting and receiving stations, including spatial, temporal, and frequency information. It also suppresses direct wave signals in the digital echo signals entering the receiving station. Furthermore, it compensates for the change in distance caused by the target's translational motion in the digital echo signals entering the receiving station.

[0162] Based on the preset bandwidth and in conjunction with the echo model, digital echo signal, and mathematical model, the first constraint condition for high-resolution imaging and the second constraint condition for the bistatic angle change rate are calculated. Finally, the spatial locations of the transmitting and receiving stations are deployed according to the first constraint condition for high-resolution imaging and the second constraint condition for the bistatic angle change rate.

[0163] By constructing the echo model and the mathematical model corresponding to the bistatic angle, and then calculating the first constraint condition for high-resolution imaging and the second constraint condition for the bistatic angle change rate, the maximum boundary value of the bistatic angle change rate under a given range resolution and bistatic angle can be quickly found. Based on the maximum boundary value, the positions of the transmitting and receiving stations can be reasonably designed to optimize the bistatic ISAR imaging configuration. This ensures that the optimal bistatic ISAR imaging configuration satisfies both the range resolution requirements and the maximum boundary condition for the bistatic angle change rate, thereby realizing the design of the bistatic ISAR imaging configuration for the target under resolution constraints.

[0164] Compared with existing bistatic ISAR imaging systems, this embodiment not only embeds the range resolution constraint into the bistatic ISAR imaging configuration design process, but also provides boundary conditions for bistatic ISAR imaging, providing a theoretical basis for the design of bistatic ISAR imaging configurations.

[0165] The advantages of this invention can be further illustrated by the following simulation experiments.

[0166] Analysis will be conducted based on the content and results of the simulation experiments:

[0167] Experimental content: For different signal resolutions, various bistatic ISAR imaging configurations are simulated. In the simulation environment, the present invention is applied to simulate the maximum boundary condition of the bistatic angle change rate under different resolutions and bistatic ISAR imaging configurations.

[0168] Please refer to Figure 3 represents the maximum permissible boundary value of the rate of change of bistatic angle for signals of different bandwidths under different bistatic angle conditions, where represents the curves corresponding to B = 0.15 GHz, B = 0.3 GHz, B = 0.5 GHz, B = 1.5 GHz, and B = 3 GHz from the outside in.

[0169] Figure 4 It is the maximum allowable boundary value of the rate of change of bistatic angle under different bistatic angle conditions in a 1m resolution scene.

[0170] Figure 5 It is the maximum allowable boundary value of the rate of change of bistatic angle under different bistatic angle conditions in a 0.5m resolution scene.

[0171] Figure 6 It is the maximum allowable boundary value of the rate of change of bistatic angle under different bistatic angle conditions in a 0.3m resolution scene.

[0172] Figure 7 It is the maximum allowable boundary value of the rate of change of bistatic angle under different bistatic angle conditions in a 0.1m resolution scene.

[0173] Figure 8 It is the maximum allowable boundary value of the rate of change of bistatic angle under different bistatic angle conditions in a 0.05m resolution scene.

[0174] The experimental results are analyzed as follows:

[0175] from Figure 3 It can be seen that, under the same bistatic ISAR imaging configuration, the larger the transmitted signal bandwidth, the smaller the maximum boundary value of the bistatic angle change rate. From Figure 3 It can also be seen that as the bibasic angle increases, the maximum boundary value of the rate of change of the bibasic angle gradually decreases. Clearly, from... Figure 3 The maximum boundary value of the bistatic angle change rate under a given signal bandwidth and bistatic angle can be quickly found. Based on this boundary value, we can optimize the bistatic ISAR imaging configuration by reasonably designing the positions of the transmitting and receiving stations, so that the optimal bistatic ISAR imaging configuration can meet both the range resolution requirements and the maximum boundary condition of the bistatic angle change rate, thereby achieving the best detection and imaging of the target.

[0176] from Figures 4-8 It can be seen that as the bibasic angle increases, the maximum boundary value of the rate of change of the bibasic angle also gradually decreases.

[0177] from Figures 4-8 It can also be seen that as the distance resolution increases, the maximum boundary value of the bibasic angle change rate gradually decreases.

[0178] Therefore, based on the design method in this embodiment, the maximum boundary value of the bistatic angle change rate under a given resolution and bistatic angle can be quickly found. Based on this boundary value, we can optimize the bistatic ISAR imaging configuration by reasonably designing the positions of the transmitting and receiving stations, so that the optimal bistatic ISAR imaging configuration can satisfy both the range resolution requirements and the maximum boundary condition of the bistatic angle change rate, thereby achieving the best detection and imaging of the target.

[0179] Please see Figure 9 This application provides an embodiment of a design apparatus for a dual-base ISAR imaging configuration, comprising:

[0180] The determining unit 901 is used to determine a set of location information for a transmitting station and a receiving station;

[0181] The first building unit 902 is used to establish a coordinate system based on the location information and the target location, and to build an echo model in the coordinate system;

[0182] The second building unit 903 is used to approximate the expansion of the bistatic angles introduced in the bistatic ISAR imaging process and to build the corresponding mathematical model.

[0183] Transmitting unit 904 is used to transmit radar signals using a transmitting station;

[0184] Receiver unit 905 is used to receive digital echo signals using a receiving station;

[0185] The calculation unit 906 is used to calculate the first constraint condition and the second constraint condition of the bibasic angle change rate of high-resolution imaging based on the preset bandwidth and in combination with the echo model, digital echo signal and mathematical model.

[0186] Deployment unit 907 is used to deploy the spatial positions of the transmitter and receiver stations according to the first constraint condition of high-resolution imaging and the second constraint condition of the bibasal angle change rate.

[0187] Please see Figure 10 This application provides another embodiment of a design device for a dual-base ISAR imaging configuration, comprising:

[0188] The determining unit 1001 is used to determine a set of location information for transmitting and receiving stations;

[0189] The first building unit 1002 is used to establish a coordinate system based on the location information and the target location, and to build an echo model in the coordinate system;

[0190] The second building unit 1003 is used to approximate the expansion of the bistatic angles introduced in the bistatic ISAR imaging process and to build the corresponding mathematical model.

[0191] Transmitting unit 1004 is used to transmit radar signals using a transmitting station;

[0192] Optionally, the transmitting unit 1004 includes:

[0193] The baseband signal generated by the frequency synthesizer is transmitted through the upconversion link and the transmitting antenna unit to radiate the radar signal to the preset area using the transmitting station.

[0194] The receiving unit 1005 is used to receive digital echo signals using a receiving station;

[0195] Optionally, the receiving unit 1005 includes:

[0196] The radio frequency signal received by the receiving antenna unit of the receiving station is converted into an intermediate frequency signal;

[0197] The intermediate frequency signal is converted into a digital echo signal.

[0198] Synchronization unit 1006 is used to synchronize the space-time-frequency information between the transmitting station and the receiving station. The space-time-frequency information includes space, time, and frequency.

[0199] The suppression unit 1007 is used to suppress the direct wave signal in the digital echo signal entering the receiving station;

[0200] The compensation unit 1008 is used to compensate the digital echo signal entering the receiving station based on the distance change caused by the target's translation when the target is in translation.

[0201] The calculation unit 1009 is used to calculate the first constraint condition and the second constraint condition of the bibasic angle change rate of high-resolution imaging based on the preset bandwidth and in combination with the echo model, digital echo signal and mathematical model.

[0202] Deployment unit 1010 is used to deploy the spatial positions of the transmitter and receiver stations according to the first constraint condition of high-resolution imaging and the second constraint condition of the bibasal angle change rate.

[0203] Please see Figure 11 This application provides an electronic device, including:

[0204] Processor 1101, memory 1103, input / output unit 1102 and bus 1104.

[0205] The processor 1101 is connected to the memory 1103, the input / output unit 1102, and the bus 1104.

[0206] The memory 1103 stores a program, and the processor 1101 calls the program to execute it, such as... Figure 1 , Figure 2 The design method of dual-base ISAR imaging configuration.

[0207] This application provides a computer-readable storage medium on which a program is stored, and when the program is executed on a computer, it performs the following... Figure 1 , Figure 2 The design method of dual-base ISAR imaging configuration.

[0208] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0209] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0210] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection between apparatuses or units through some interfaces, and may be electrical, mechanical, or other forms.

[0211] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0212] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0213] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

Claims

1. A design method for a dual-base ISAR imaging configuration, characterized in that, include: Determine the location information of a set of transmitting and receiving stations; A coordinate system is established based on the location information and the target location, and an echo model is constructed under the coordinate system. The cosine values ​​of the bistatic angles introduced in the bistatic ISAR imaging process are expanded and approximated by a first-order Taylor series, and a rotation approximation model of the bistatic ISAR imaging is constructed. Use the aforementioned transmitting station to transmit radar signals; The receiving station is used to receive digital echo signals; Based on the preset bandwidth and in combination with the echo model, the digital echo signal and the mathematical model, calculate the first constraint condition for high-resolution imaging and the second constraint condition for the bibasal angle change rate. The spatial positions of the transmitting station and the receiving station are deployed according to the first constraint condition of the high-resolution imaging and the second constraint condition of the bistatic angle change rate.

2. The design method according to claim 1, characterized in that, After receiving the digital echo signal using the receiving station, and before calculating the first constraint condition for high-resolution imaging and the second constraint condition for the bistatic angle change rate based on the preset bandwidth and in conjunction with the echo model, the digital echo signal, and the mathematical model, the design method further includes: The space-time-frequency information between the transmitting station and the receiving station is synchronized, and the space-time-frequency information includes space, time and frequency.

3. The design method according to claim 1, characterized in that, After receiving the digital echo signal using the receiving station, and before calculating the first constraint condition for high-resolution imaging and the second constraint condition for the bistatic angle change rate based on the preset bandwidth and in conjunction with the echo model, the digital echo signal, and the mathematical model, the design method further includes: The direct wave signal in the digital echo signal entering the receiving station is suppressed.

4. The design method according to claim 1, characterized in that, After receiving the digital echo signal using the receiving station, and before calculating the first constraint condition for high-resolution imaging and the second constraint condition for the bistatic angle change rate based on the preset bandwidth and in conjunction with the echo model, the digital echo signal, and the mathematical model, the design method further includes: When the target moves, the digital echo signal entering the receiving station is compensated based on the distance change caused by the target's translation.

5. The design method according to any one of claims 1 to 4, characterized in that, The use of the transmitting station to transmit radar signals includes: The baseband signal generated by the frequency synthesizer is used to radiate radar signals to a preset area via an up-conversion link and a transmitting antenna unit using the aforementioned transmitting station.

6. The design method according to any one of claims 1 to 4, characterized in that, The method of receiving digital echo signals using the receiving station includes: The radio frequency signal received by the receiving antenna unit of the receiving station is converted into an intermediate frequency signal; The intermediate frequency signal is converted into a digital echo signal.

7. A design device for a dual-base ISAR imaging configuration, characterized in that, include: The determination unit is used to determine the location information of a set of transmitting and receiving stations; The first construction unit is used to establish a coordinate system based on the location information and the target location, and to construct an echo model in the coordinate system. The second construction unit is used to perform a first-order Taylor series expansion and approximation on the cosine value of the bistatic angle introduced in the bistatic ISAR imaging process, and to construct the rotation approximation model of the bistatic ISAR imaging. The transmitting unit is used to transmit radar signals using the transmitting station; A receiving unit is used to receive digital echo signals using the receiving station; The calculation unit is used to calculate the first constraint condition for high-resolution imaging and the second constraint condition for the bibasal angle change rate based on the preset bandwidth and in combination with the echo model, the digital echo signal and the mathematical model. The deployment unit is used to deploy the spatial positions of the transmitting station and the receiving station according to the first constraint condition of the high-resolution imaging and the second constraint condition of the bistatic angle change rate.

8. The design apparatus according to claim 7, characterized in that, The design apparatus, following the receiving unit and preceding the calculation unit, further includes: The synchronization unit is used to synchronize the space-time-frequency information between the transmitting station and the receiving station, wherein the space-time-frequency information includes space, time, and frequency.

9. The design apparatus according to claim 7, characterized in that, The design apparatus, following the receiving unit and preceding the calculation unit, further includes: The suppression unit is used to suppress the direct wave signal in the digital echo signal entering the receiving station.

10. An electronic device, characterized in that, It includes a processor, a memory, an input / output unit, and a bus, wherein the processor is connected to the memory, the input / output unit, and the bus; The memory stores a program, which the processor invokes to execute the design method as described in any one of claims 1 to 6.

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