A single-bit synthetic aperture radar imaging method and system based on slow-time fluctuation threshold

Abstract

The present invention discloses a single-bit synthetic aperture radar imaging method and system based on a slow-time fluctuation threshold, the method comprising: obtaining a Doppler bandwidth parameter and determining a quantization threshold frequency; determining a pulse repetition frequency, obtaining a target repetition frequency bandwidth ratio according to the pulse repetition frequency and the quantization threshold frequency, and determining a recoverable interval width parameter according to the target repetition frequency bandwidth ratio; obtaining Rayleigh distribution parameters, calculating a single-bit quantization threshold amplitude according to the Rayleigh distribution parameters and the recoverable interval width parameters, and calculating a quantization threshold signal according to the single-bit quantization threshold amplitude and the quantization threshold frequency; obtaining an analog echo signal, and performing single-bit quantization processing and matched filtering processing on the analog echo signal according to the quantization threshold signal to obtain a target radar image. The present invention can significantly reduce the radar hardware burden and reduce the radar cost by setting a slow-time fluctuation threshold signal in the single-bit quantization process, and obtain a high-quality synthetic aperture radar image.

Description

Technical Field

[0001] The present invention relates to the field of radar signal processing technology, and in particular to a single-bit synthetic aperture radar imaging method, system, terminal and computer-readable storage medium based on a slow-time fluctuation threshold. Background Art

[0002] Synthetic Aperture Radar (SAR) is used to obtain the echo intensity distribution map of the radar signal scattered by ground targets, that is, the ground scattering information, and display this information in the form of radar images.

[0003] In order to make the obtained radar image accurately reflect the scattering information of the ground objects, the synthetic aperture radar needs to emit a large bandwidth signal and use a high-precision analog-to-digital converter to quantize the analog echo. This makes the amount of synthetic aperture radar echo data huge, which makes it impossible to adapt to small, resource-limited platforms (such as drones).

[0004] Therefore, the prior art still needs to be improved and developed. Summary of the invention

[0005] The main purpose of the present invention is to provide a single-bit synthetic aperture radar imaging method, system, terminal and computer-readable storage medium based on a slow-time fluctuation threshold, aiming to solve the problem in the prior art that synthetic aperture radar needs to transmit a large-bandwidth signal and use a high-precision analog-to-digital converter to quantize the analog echo, resulting in a huge amount of synthetic aperture radar echo data and cannot be adapted to small platforms with limited resources (such as drones, etc.).

[0006] To achieve the above object, the present invention provides a single-bit synthetic aperture radar imaging method based on a slow time fluctuation threshold, and the single-bit synthetic aperture radar imaging method based on a slow time fluctuation threshold comprises the following steps:

[0007] Acquiring a Doppler bandwidth parameter, and determining a quantization threshold frequency according to the Doppler bandwidth parameter;

[0008] Determine a pulse repetition frequency, obtain a target repetition frequency bandwidth ratio according to the pulse repetition frequency and the quantization threshold frequency, and determine a recoverable interval width parameter according to the target repetition frequency bandwidth ratio;

[0009] Obtaining Rayleigh distribution parameters, calculating a single-bit quantization threshold amplitude according to the Rayleigh distribution parameters and the recoverable interval width parameter, and calculating a quantization threshold signal according to the single-bit quantization threshold amplitude and the quantization threshold frequency;

[0010] An analog echo signal is acquired, and single-bit quantization processing and matched filtering processing are performed on the analog echo signal according to the quantization threshold signal to obtain a target radar image.

[0011] Optionally, the single-bit synthetic aperture radar imaging method based on slow-time fluctuation threshold, wherein the acquiring of Doppler bandwidth parameters and the determining of quantization threshold frequency according to the Doppler bandwidth parameters specifically include:

[0012] Acquire a radar transmission signal and a radar motion parameter, and determine a Doppler bandwidth parameter according to the radar transmission signal and the radar motion parameter;

[0013] The numerical value corresponding to the Doppler bandwidth parameter is set as the quantization threshold frequency.

[0014] Optionally, the single-bit synthetic aperture radar imaging method based on slow time fluctuation threshold, wherein the determining of the pulse repetition frequency, obtaining the target repetition frequency bandwidth ratio according to the pulse repetition frequency and the quantization threshold frequency, and determining the recoverable interval width parameter according to the target repetition frequency bandwidth ratio, specifically includes:

[0015] Acquire the user's radar image quality requirement, and set the pulse repetition frequency according to the radar image quality requirement;

[0016] Obtaining a repetition frequency bandwidth ratio according to the pulse repetition frequency and the quantization threshold frequency, and obtaining a target repetition frequency bandwidth ratio when the target repetition frequency bandwidth ratio is an odd number;

[0017] A preset threshold amplitude-related calculation parameter table is obtained, and according to the target repetition frequency bandwidth ratio, a search is performed in the preset threshold amplitude-related calculation parameter table to obtain a recoverable interval width parameter corresponding to the target repetition frequency bandwidth ratio.

[0018] Optionally, the single-bit synthetic aperture radar imaging method based on slow-time fluctuation threshold, wherein the obtaining of Rayleigh distribution parameters, calculating the single-bit quantization threshold amplitude according to the Rayleigh distribution parameters and the recoverable interval width parameter, and calculating the quantization threshold signal according to the single-bit quantization threshold amplitude and the quantization threshold frequency, specifically includes:

[0019] Transmitting a preset number of test pulse signals through a radar transmitter, and receiving a test echo signal returned after the test pulse signal is transmitted;

[0020] Performing modulus processing and averaging processing on the test echo signal to obtain Rayleigh distribution parameters;

[0021] The single-bit quantization threshold amplitude is calculated according to the Rayleigh distribution parameter and the recoverable interval width parameter, wherein the expression of the single-bit quantization threshold amplitude is:

[0022] ;

[0023] in, is the single-bit quantization threshold amplitude, is the Rayleigh distribution parameter, is the recoverable interval width parameter;

[0024] A quantization threshold signal is calculated based on the single-bit quantization threshold amplitude and the quantization threshold frequency.

[0025] Optionally, in the single-bit synthetic aperture radar imaging method based on slow-time fluctuation threshold, the expression of the quantization threshold signal is:

[0026] ;

[0027] in, To quantize the threshold signal, is an exponential function, is an imaginary unit, To quantize the threshold frequency, Slow time for radar.

[0028] Optionally, the single-bit synthetic aperture radar imaging method based on slow-time fluctuation threshold, wherein the acquiring of analog echo signals, and performing single-bit quantization processing and matched filtering processing on the analog echo signals according to the quantization threshold signal to obtain a target radar image, specifically includes:

[0029] Transmitting a target pulse signal through a radar transmitter, and receiving a simulated echo signal returned after the target pulse signal is transmitted;

[0030] Performing single-bit quantization processing on the analog echo signal according to the quantization threshold signal to obtain a binary digital signal string;

[0031] A preset imaging algorithm is determined, and matched filtering is performed on the binary digital signal string according to the preset imaging algorithm to obtain a target radar image.

[0032] Optionally, in the single-bit synthetic aperture radar imaging method based on slow-time fluctuation threshold, the expression of the simulated echo signal is:

[0033] ;

[0034] in, To simulate the echo signal, Fast time for radar, For radar slow time, is the simulated echo signal amplitude, is an exponential function, is an imaginary unit, is the phase of the simulated echo signal.

[0035] In addition, to achieve the above-mentioned purpose, the present invention also provides a single-bit synthetic aperture radar imaging system based on a slow time fluctuation threshold, wherein the single-bit synthetic aperture radar imaging system based on a slow time fluctuation threshold comprises:

[0036] A quantization threshold frequency determination module, used to obtain a Doppler bandwidth parameter and determine a quantization threshold frequency according to the Doppler bandwidth parameter;

[0037] A recoverable interval width parameter determination module, used to determine a pulse repetition frequency, obtain a target repetition frequency bandwidth ratio according to the pulse repetition frequency and the quantization threshold frequency, and determine a recoverable interval width parameter according to the target repetition frequency bandwidth ratio;

[0038] A quantization threshold signal calculation module, used to obtain Rayleigh distribution parameters, calculate a single-bit quantization threshold amplitude according to the Rayleigh distribution parameters and the recoverable interval width parameter, and calculate a quantization threshold signal according to the single-bit quantization threshold amplitude and the quantization threshold frequency;

[0039] The target radar image generation module is used to obtain a simulated echo signal, and perform single-bit quantization processing and matched filtering processing on the simulated echo signal according to the quantization threshold signal to obtain a target radar image.

[0040] In addition, to achieve the above-mentioned purpose, the present invention also provides a terminal, wherein the terminal includes: a memory, a processor, and a single-bit synthetic aperture radar imaging program based on a slow time fluctuation threshold stored in the memory and executable on the processor, wherein the single-bit synthetic aperture radar imaging program based on a slow time fluctuation threshold implements the steps of the single-bit synthetic aperture radar imaging method based on a slow time fluctuation threshold as described above when the single-bit synthetic aperture radar imaging program based on a slow time fluctuation threshold is executed by the processor.

[0041] In addition, to achieve the above-mentioned purpose, the present invention also provides a computer-readable storage medium, wherein the computer-readable storage medium stores a single-bit synthetic aperture radar imaging program based on a slow time fluctuation threshold, and when the single-bit synthetic aperture radar imaging program based on a slow time fluctuation threshold is executed by a processor, the steps of the single-bit synthetic aperture radar imaging method based on a slow time fluctuation threshold as described above are implemented.

[0042] In the present invention, a Doppler bandwidth parameter is obtained, and a quantization threshold frequency is determined according to the Doppler bandwidth parameter; a pulse repetition frequency is determined, and a target repetition frequency bandwidth ratio is obtained according to the pulse repetition frequency and the quantization threshold frequency, and a recoverable interval width parameter is determined according to the target repetition frequency bandwidth ratio; Rayleigh distribution parameters are obtained, and a single-bit quantization threshold amplitude is calculated according to the Rayleigh distribution parameters and the recoverable interval width parameters, and a quantization threshold signal is calculated according to the single-bit quantization threshold amplitude and the quantization threshold frequency; an analog echo signal is obtained, and single-bit quantization processing and matched filtering processing are performed on the analog echo signal according to the quantization threshold signal to obtain a target radar image. The present invention sets a quantization threshold signal by calculating the pulse repetition frequency and the single-bit quantization threshold amplitude, and performs single-bit quantization processing on the analog echo signal received by the radar receiver through the quantization threshold signal, which can effectively reduce the sampling burden of the synthetic aperture radar system, further simplify the single-bit quantization process, and at the same time, can also significantly save system resources and reduce the burden on radar hardware. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 It is a flow chart of a preferred embodiment of the single-bit synthetic aperture radar imaging method based on slow time fluctuation threshold of the present invention;

[0044] Figure 2 is a schematic diagram of an original 8-bit synthetic aperture radar image in the prior art;

[0045] Figure 3 It is a schematic diagram of a synthetic aperture radar image of a single-bit imaging method in the prior art;

[0046] Figure 4 Schematic diagram of a single-bit synthetic aperture radar image obtained by the present invention according to a preferred embodiment of the single-bit synthetic aperture radar imaging method based on a slow time fluctuation threshold of the present invention;

[0047] Figure 5 It is a structural diagram of a preferred embodiment of a single-bit synthetic aperture radar imaging system based on a slow time fluctuation threshold of the present invention;

[0048] Figure 6 It is a structural diagram of a preferred embodiment of the terminal of the present invention. DETAILED DESCRIPTION

[0049] In order to make the purpose, technical solution and advantages of the present invention clearer and more specific, the present invention is further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0050] Synthetic Aperture Radar (SAR) is used to obtain the echo intensity distribution map of the radar signal scattered by ground targets, that is, the ground scattering information, and display this information in the form of radar images. In order to make the obtained radar image accurately reflect the ground scattering information, the synthetic aperture radar needs to transmit a large bandwidth signal and use a high-precision analog-to-digital converter to quantize the analog echo, so the amount of synthetic aperture radar echo data is huge. The storage, transmission and processing of massive data requires a lot of time, energy and hardware resources, so the currently widely used synthetic aperture radar system is not well adapted to small, resource-limited platforms (such as drones).

[0051] To solve the above problems, the present invention adopts a single-bit synthetic aperture radar. The single-bit synthetic aperture radar can quantize the analog echo data into only 1 bit, which greatly reduces the amount of radar echo data, increases the rate of signal sampling and quantization, and reduces the power consumption required by the synthetic aperture radar system. It can effectively make up for the above-mentioned shortcomings of the synthetic aperture radar system and expand the application of the synthetic aperture radar system on resource-constrained platforms.

[0052] Furthermore, unlike real aperture radar imaging, the relative motion between the radar platform and the ground object makes the synthetic aperture radar echo signal have the characteristics of Doppler modulation in the azimuth direction. Unlike the prior art that focuses on setting the quantization threshold in the distance direction, the present invention fully combines the characteristics of the synthetic aperture radar azimuth signal and sets a quantization threshold that fluctuates with the synthetic aperture radar azimuth pulse. The fluctuation characteristics of the threshold can effectively alleviate the synthetic aperture radar image distortion problem caused by single-bit quantization, and can also effectively suppress the undesired interference energy introduced in the single-bit quantization process. The present invention has no requirements for the sparsity of the imaging scene and is compatible with traditional fast and low-complexity imaging algorithms. Secondly, the present invention can effectively reduce the sampling burden of the synthetic aperture radar system and further simplify the single-bit quantization process. Finally, the present invention provides a quantitative design criterion for the threshold amplitude. Under the "image structure similarity" index, compared with the existing single-bit synthetic aperture radar imaging method, the synthetic aperture radar image restored by the present invention has a similarity of 91.8% with the 8-bit synthetic aperture radar image, which is better than the 89.4% of the existing method.

[0053] The single-bit synthetic aperture radar imaging method based on slow time fluctuation threshold described in the preferred embodiment of the present invention is as follows: Figure 1 As shown, the single-bit synthetic aperture radar imaging method based on slow time fluctuation threshold comprises the following steps:

[0054] Step S10: Acquire a Doppler bandwidth parameter, and determine a quantization threshold frequency according to the Doppler bandwidth parameter.

[0055] Specifically, a radar transmission signal and a radar motion parameter are acquired, and a Doppler bandwidth parameter is determined according to the radar transmission signal and the radar motion parameter; and a numerical value corresponding to the Doppler bandwidth parameter is set as a quantization threshold frequency.

[0056] The present invention is for quantizing the threshold frequency Pulse repetition frequency of synthetic aperture radar system The design process is as follows: Theoretical analysis shows that using the quantized threshold signal When used as a single-bit quantization threshold, the undesired signal energy will be generated in the Doppler spectrum If the design ( is the Doppler bandwidth), the undesired signal can be completely separated from the imaging signal in the Doppler domain. It is necessary to coordinate with a larger system pulse repetition frequency to reduce the undesired energy folded back to the main Doppler band. Therefore, the boundary condition is taken in the present invention. .

[0057] In addition, in practice, for any SAR system, the pulse repetition frequency is limited, so there will inevitably be undesired signal energy folded back into the main frequency band. The ratio of the pulse repetition frequency to the Doppler bandwidth is defined as the repetition frequency-bandwidth ratio: . (The boundary condition in this invention is , so the Doppler bandwidth here is The value of the quantization threshold frequency Instead) Theoretical analysis shows that when the designed repetition rate-bandwidth ratio When is an odd number, the influence of the undesired signal on the imaging signal is minimal. Therefore, the repetition frequency-bandwidth ratio is further designed in the present invention. is an odd number. It should be noted that due to the system Doppler bandwidth It is known that the quantization threshold frequency It is known that in this technology, although the repetition rate-bandwidth ratio is designed is an odd number, but the specific system pulse repetition frequency depends on the user (that is, the pulse repetition frequency is set according to the user's radar image quality requirements). Specifically, when the user pursues higher radar image quality, the repetition frequency-bandwidth ratio It can be larger (the higher the user's radar image quality requirement, the larger the pulse repetition frequency setting and the corresponding repetition rate-bandwidth ratio), because a larger pulse repetition frequency means more echo data, that is, more ground object information; on the contrary, if the user pays more attention to reducing the amount of echo data, a smaller repetition rate-bandwidth ratio value can be set, because the amount of echo data is proportional to the pulse repetition frequency.

[0058] Step S20, determining a pulse repetition frequency, obtaining a target repetition frequency-bandwidth ratio according to the pulse repetition frequency and the quantization threshold frequency, and determining a recoverable interval width parameter according to the target repetition frequency-bandwidth ratio.

[0059] Specifically, the user's radar image quality requirement is obtained, and the pulse repetition frequency is set according to the radar image quality requirement; the repetition frequency bandwidth ratio is obtained according to the pulse repetition frequency and the quantization threshold frequency, and when the target repetition frequency bandwidth ratio is an odd number, the target repetition frequency bandwidth ratio is obtained; a preset threshold amplitude related calculation parameter table is obtained, and according to the target repetition frequency bandwidth ratio, the preset threshold amplitude related calculation parameter table is searched to obtain a recoverable interval width parameter corresponding to the target repetition frequency bandwidth ratio.

[0060] Through theoretical analysis, the single-bit quantization threshold amplitude is is the best. Among them, That is the single-bit quantization threshold amplitude designed by the present invention, is the width of the recoverable interval of the signal, The specific value depends on the repetition rate-bandwidth ratio designed previously. Change due to change. Repetition rate-bandwidth ratio There is no analytical solution for the relationship between the equation, only a numerical solution, so the corresponding specific related parameter values ​​can be directly obtained from Table 1 (i.e., according to the repetition frequency-bandwidth ratio Directly obtain the corresponding recoverable interval width ):

[0061] Table 1: Threshold amplitude related calculation parameters

[0062]

[0063] According to Table 1, the present invention can set the repetition rate-bandwidth ratio Look up in Table 1 and get the repetition rate-bandwidth ratio The corresponding recoverable interval width .

[0064] Step S30, obtaining Rayleigh distribution parameters, calculating a single-bit quantization threshold amplitude according to the Rayleigh distribution parameters and the recoverable interval width parameter, and calculating a quantization threshold signal according to the single-bit quantization threshold amplitude and the quantization threshold frequency.

[0065] Specifically, a preset number of test pulse signals are transmitted through a radar transmitter, and a test echo signal returned after the test pulse signal is transmitted is received; the test echo signal is subjected to modulo processing and averaging processing to obtain Rayleigh distribution parameters; a single-bit quantization threshold amplitude is calculated according to the Rayleigh distribution parameters and the recoverable interval width parameter, wherein the expression of the single-bit quantization threshold amplitude is: ;in, is the single-bit quantization threshold amplitude, is the Rayleigh distribution parameter, is a recoverable interval width parameter; a quantization threshold signal is calculated according to the single-bit quantization threshold amplitude and the quantization threshold frequency. Further, the expression of the quantization threshold signal is: ;in, To quantize the threshold signal, is an exponential function, is an imaginary unit, To quantize the threshold frequency, Slow time for radar.

[0066] It can be understood that because the real and imaginary parts of the synthetic aperture radar echo signal satisfy the zero-mean independent Gaussian distribution, its amplitude satisfies the Rayleigh distribution. The Rayleigh distribution parameters of the radar echo amplitude are Before the radar enters the formal observation scene, it can first send out several pulses to obtain echoes. The modulus of these echo complex data is taken and the average is divided by , you can get the parameters The estimated value of .

[0067] Therefore, in general, the Doppler bandwidth parameter given by the radar system is The quantization threshold frequency can be designed ; Secondly, select the pulse repetition frequency according to user needs , and satisfies is an odd number; then the recoverable interval width parameter of the signal can be obtained from Table 1 , and finally combined with the estimated signal echo parameter distribution , in order to calculate the amplitude of the quantization threshold ; After obtaining the quantization threshold frequency in the above step and the single-bit quantization threshold amplitude After that, the quantization threshold signal can be designed .

[0068] Step S40: Acquire an analog echo signal, and perform single-bit quantization processing and matched filtering processing on the analog echo signal according to the quantization threshold signal to obtain a target radar image.

[0069] Specifically, a target pulse signal is transmitted through a radar transmitter, and a simulated echo signal returned after the target pulse signal is transmitted is received; wherein the expression of the simulated echo signal is: ;in, To simulate the echo signal, Fast time for radar, For radar slow time, is the simulated echo signal amplitude, is an exponential function, is an imaginary unit, The method comprises the steps of: performing single-bit quantization processing on the analog echo signal according to the quantization threshold signal to obtain a binary digital signal string; determining a preset imaging algorithm, and performing matched filtering processing on the binary digital signal string according to the preset imaging algorithm to obtain a target radar image.

[0070] It can be understood that the radar generates a pulse signal and transmits the pulse signal through the antenna. The signal propagates in space in the form of electromagnetic waves. When it hits a ground object, the signal returns to the radar antenna in the form of an echo and is recorded by the radar receiver. Therefore, the present invention is set at the radar receiver, and the SAR echo signal expression is: The designed quantization threshold signal expression is: ;in, is the simulated echo signal amplitude, is an exponential function, is an imaginary unit, To simulate the echo signal phase, is the single-bit quantization threshold amplitude, To quantize the threshold frequency, and are radar fast time and slow time respectively. In addition, let the pulse repetition frequency of the SAR system be , the Doppler bandwidth parameter is , where the Doppler bandwidth parameter The specific value is known, depending on the transmitted signal and the radar platform motion parameters. In addition, the pulse repetition frequency , single-bit quantization threshold amplitude and quantization threshold frequency It is an unknown quantity (all of which can be solved through the above steps) and is also the parameter that the present invention focuses on designing.

[0071] After obtaining the quantization threshold signal, the present invention can use the designed quantization threshold signal Directly simulate the echo signal Perform single-bit quantization processing and then use the existing synthetic aperture radar imaging algorithm. The specific implementation process is: input the analog echo collected by the radar receiver into the positive pole of the radar quantization comparator, and input the set quantization threshold signal into the negative pole of the radar quantization comparator to complete the single-bit quantization process. The output result of the quantization comparator is a binary digital signal string interlaced with +1 and -1. After obtaining the binary digital signal string, the existing imaging algorithm can be used. The specific implementation process is: construct a two-dimensional matched filter based on the known parameters of the radar system, and perform matched filtering processing on the binary digital signal string to obtain the final radar image.

[0072] It should be noted that the single-bit quantization method in the prior art sets a time-varying (fluctuation) threshold in the radar range direction, while the present invention sets a fluctuation threshold in the azimuth direction. In some synthetic aperture radar systems (such as strip mode synthetic aperture radar systems), the present invention can significantly save system resources and reduce the burden on radar hardware.

[0073] Imaging effect comparison: Figure 2 , Figure 3 as well as Figure 4 As shown, Figure 2 is the original 8-bit synthetic aperture radar image, Figure 3 is the synthetic aperture radar image of the existing single-bit imaging method, Figure 4 is a single-bit synthetic aperture radar image obtained by the present invention. The present invention uses "image structure similarity" as the analysis index to Figure 2 , Figure 3 as well as Figure 4 Quantitative numerical calculation of SAR images in Figure 2 , Figure 3 as well as Figure 4 The vertical axis is the image structure similarity), and the calculation results show that the structural similarity between the SAR image obtained by the present invention and the original SAR image obtained by 8-bit quantization reaches 91.8%, which is better than 89.4% of the existing method.

[0074] Furthermore, if Figure 5 As shown, based on the above-mentioned single-bit synthetic aperture radar imaging method based on slow time fluctuation threshold, the present invention also provides a single-bit synthetic aperture radar imaging system based on slow time fluctuation threshold, wherein the single-bit synthetic aperture radar imaging system based on slow time fluctuation threshold includes:

[0075] A quantization threshold frequency determination module 51 is used to obtain a Doppler bandwidth parameter and determine a quantization threshold frequency according to the Doppler bandwidth parameter;

[0076] A recoverable interval width parameter determination module 52 is used to determine a pulse repetition frequency, obtain a target repetition frequency bandwidth ratio according to the pulse repetition frequency and the quantization threshold frequency, and determine a recoverable interval width parameter according to the target repetition frequency bandwidth ratio;

[0077] A quantization threshold signal calculation module 53, used to obtain Rayleigh distribution parameters, calculate a single-bit quantization threshold amplitude according to the Rayleigh distribution parameters and the recoverable interval width parameter, and calculate a quantization threshold signal according to the single-bit quantization threshold amplitude and the quantization threshold frequency;

[0078] The target radar image generation module 54 is used to obtain an analog echo signal, and perform single-bit quantization processing and matched filtering processing on the analog echo signal according to the quantization threshold signal to obtain a target radar image.

[0079] Furthermore, if Figure 6 As shown, based on the above-mentioned single-bit synthetic aperture radar imaging method and system based on slow-time fluctuation threshold, the present invention also provides a terminal accordingly, and the terminal includes a processor 10, a memory 20 and a display 30. Figure 6 Only some components of the terminal are shown, but it should be understood that it is not required to implement all of the components shown, and more or fewer components may be implemented instead.

[0080] In some embodiments, the memory 20 may be an internal storage unit of the terminal, such as a hard disk or memory of the terminal. In other embodiments, the memory 20 may also be an external storage device of the terminal, such as a plug-in hard disk, a smart memory card (Smart Media Card, SMC), a secure digital (SecureDigital, SD) card, a flash card (Flash Card), etc. equipped on the terminal. Further, the memory 20 may also include both an internal storage unit of the terminal and an external storage device. The memory 20 is used to store application software and various types of data installed in the terminal, such as the program code of the installation terminal. The memory 20 may also be used to temporarily store data that has been output or is to be output. In one embodiment, a single-bit synthetic aperture radar imaging program 40 based on a slow time fluctuation threshold is stored on the memory 20, and the single-bit synthetic aperture radar imaging program 40 based on a slow time fluctuation threshold can be executed by the processor 10, thereby realizing the single-bit synthetic aperture radar imaging method based on a slow time fluctuation threshold in the present application.

[0081] In some embodiments, the processor 10 may be a central processing unit (CPU), a microprocessor or other data processing chip, used to run the program code or process data stored in the memory 20, such as executing the single-bit synthetic aperture radar imaging method based on the slow-time fluctuation threshold.

[0082] In some embodiments, the display 30 may be an LED display, a liquid crystal display, a touch-sensitive liquid crystal display, an OLED (Organic Light-Emitting Diode) touch device, etc. The display 30 is used to display information on the terminal and to display a visual user interface. The terminals communicate with each other via a system bus.

[0083] In one embodiment, when the processor 10 executes the single-bit synthetic aperture radar imaging program 40 based on slow time fluctuation threshold in the memory 20, the steps of the single-bit synthetic aperture radar imaging method based on slow time fluctuation threshold as described above are implemented.

[0084] The present invention also provides a computer-readable storage medium, wherein the computer-readable storage medium stores a single-bit synthetic aperture radar imaging program based on a slow-time fluctuation threshold, and when the single-bit synthetic aperture radar imaging program based on a slow-time fluctuation threshold is executed by a processor, the steps of the single-bit synthetic aperture radar imaging method based on a slow-time fluctuation threshold as described above are implemented.

[0085] In summary, the present invention provides a single-bit synthetic aperture radar imaging method, system and terminal based on slow time fluctuation threshold, the method comprising: obtaining Doppler bandwidth parameters, and determining quantization threshold frequency according to the Doppler bandwidth parameters; determining pulse repetition frequency, obtaining target repetition frequency bandwidth ratio according to the pulse repetition frequency and the quantization threshold frequency, and determining recoverable interval width parameters according to the target repetition frequency bandwidth ratio; obtaining Rayleigh distribution parameters, calculating single-bit quantization threshold amplitude according to the Rayleigh distribution parameters and the recoverable interval width parameters, and calculating quantization threshold signal according to the single-bit quantization threshold amplitude and the quantization threshold frequency; obtaining analog echo signal, and performing single-bit quantization processing and matched filtering processing on the analog echo signal according to the quantization threshold signal to obtain a target radar image. The present invention sets the quantization threshold signal by calculating the pulse repetition frequency and the single-bit quantization threshold amplitude, and performs single-bit quantization processing on the analog echo signal received by the radar receiver through the quantization threshold signal, which can effectively reduce the sampling burden of the synthetic aperture radar system, further simplify the single-bit quantization process, and at the same time, can also significantly save system resources and reduce the burden on radar hardware.

[0086] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or terminal including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or terminal. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the presence of other identical elements in the process, method, article or terminal including the element.

[0087] Of course, those skilled in the art can understand that all or part of the processes in the above-mentioned embodiments can be implemented by instructing related hardware (such as a processor, a controller, etc.) through a computer program, and the program can be stored in a computer-readable storage medium that can be read by a computer, and the program can include the processes of the above-mentioned method embodiments when executed. The computer-readable storage medium can be a memory, a disk, an optical disk, etc.

[0088] It should be understood that the application of the present invention is not limited to the above examples. For ordinary technicians in this field, improvements or changes can be made based on the above description. All these improvements and changes should fall within the scope of protection of the claims attached to the present invention.

Claims

1. A single-bit synthetic aperture radar imaging method based on slow time fluctuation threshold, characterized in that: The single-bit synthetic aperture radar imaging method based on slow time fluctuation threshold comprises: Acquiring a Doppler bandwidth parameter, and determining a quantization threshold frequency according to the Doppler bandwidth parameter; The obtaining of the Doppler bandwidth parameter and determining the quantization threshold frequency according to the Doppler bandwidth parameter specifically includes: Acquire a radar transmission signal and a radar motion parameter, and determine a Doppler bandwidth parameter according to the radar transmission signal and the radar motion parameter; Setting the value corresponding to the Doppler bandwidth parameter to a quantization threshold frequency; Determine a pulse repetition frequency, obtain a target repetition frequency bandwidth ratio according to the pulse repetition frequency and the quantization threshold frequency, and determine a recoverable interval width parameter according to the target repetition frequency bandwidth ratio; Obtaining Rayleigh distribution parameters, calculating a single-bit quantization threshold amplitude according to the Rayleigh distribution parameters and the recoverable interval width parameter, and calculating a quantization threshold signal according to the single-bit quantization threshold amplitude and the quantization threshold frequency; The obtaining of Rayleigh distribution parameters, calculating a single-bit quantization threshold amplitude according to the Rayleigh distribution parameters and the recoverable interval width parameter, and calculating a quantization threshold signal according to the single-bit quantization threshold amplitude and the quantization threshold frequency specifically includes: Transmitting a preset number of test pulse signals through a radar transmitter, and receiving a test echo signal returned after the test pulse signal is transmitted; Performing modulus processing and averaging processing on the test echo signal to obtain Rayleigh distribution parameters; The single-bit quantization threshold amplitude is calculated according to the Rayleigh distribution parameter and the recoverable interval width parameter, wherein the expression of the single-bit quantization threshold amplitude is: ； in, is the single-bit quantization threshold amplitude, is the Rayleigh distribution parameter, is the recoverable interval width parameter; Calculating a quantization threshold signal according to the single-bit quantization threshold amplitude and the quantization threshold frequency; The expression of the quantization threshold signal is: ； in, To quantize the threshold signal, is an exponential function, is an imaginary unit, To quantize the threshold frequency, Slow time for radar; An analog echo signal is acquired, and single-bit quantization processing and matched filtering processing are performed on the analog echo signal according to the quantization threshold signal to obtain a target radar image.

2. The single-bit synthetic aperture radar imaging method based on slow time fluctuation threshold according to claim 1, characterized in that: The determining of the pulse repetition frequency, obtaining a target repetition frequency bandwidth ratio according to the pulse repetition frequency and the quantization threshold frequency, and determining a recoverable interval width parameter according to the target repetition frequency bandwidth ratio specifically includes: Acquire the user's radar image quality requirement, and set the pulse repetition frequency according to the radar image quality requirement; Obtaining a repetition frequency bandwidth ratio according to the pulse repetition frequency and the quantization threshold frequency, and obtaining a target repetition frequency bandwidth ratio when the target repetition frequency bandwidth ratio is an odd number; A preset threshold amplitude-related calculation parameter table is obtained, and according to the target repetition frequency bandwidth ratio, a search is performed in the preset threshold amplitude-related calculation parameter table to obtain a recoverable interval width parameter corresponding to the target repetition frequency bandwidth ratio.

3. The single-bit synthetic aperture radar imaging method based on slow time fluctuation threshold according to claim 1, characterized in that: The acquiring of the analog echo signal, and performing single-bit quantization processing and matched filtering processing on the analog echo signal according to the quantization threshold signal to obtain a target radar image specifically includes: Transmitting a target pulse signal through a radar transmitter, and receiving a simulated echo signal returned after the target pulse signal is transmitted; Performing single-bit quantization processing on the analog echo signal according to the quantization threshold signal to obtain a binary digital signal string; A preset imaging algorithm is determined, and matched filtering is performed on the binary digital signal string according to the preset imaging algorithm to obtain a target radar image.

4. The single-bit synthetic aperture radar imaging method based on slow time fluctuation threshold according to claim 1, characterized in that: The expression of the simulated echo signal is: ； in, To simulate the echo signal, Fast time for radar, For radar slow time, is the simulated echo signal amplitude, is an exponential function, is an imaginary unit, is the phase of the simulated echo signal.

5. A single-bit synthetic aperture radar imaging system based on slow time fluctuation threshold, characterized in that: The single-bit synthetic aperture radar imaging system based on slow time fluctuation threshold comprises: A quantization threshold frequency determination module, used to obtain a Doppler bandwidth parameter and determine a quantization threshold frequency according to the Doppler bandwidth parameter; The obtaining of the Doppler bandwidth parameter and determining the quantization threshold frequency according to the Doppler bandwidth parameter specifically includes: Acquire a radar transmission signal and a radar motion parameter, and determine a Doppler bandwidth parameter according to the radar transmission signal and the radar motion parameter; Setting the value corresponding to the Doppler bandwidth parameter to a quantization threshold frequency; A recoverable interval width parameter determination module, used to determine a pulse repetition frequency, obtain a target repetition frequency bandwidth ratio according to the pulse repetition frequency and the quantization threshold frequency, and determine a recoverable interval width parameter according to the target repetition frequency bandwidth ratio; A quantization threshold signal calculation module, used to obtain Rayleigh distribution parameters, calculate a single-bit quantization threshold amplitude according to the Rayleigh distribution parameters and the recoverable interval width parameter, and calculate a quantization threshold signal according to the single-bit quantization threshold amplitude and the quantization threshold frequency; The obtaining of Rayleigh distribution parameters, calculating a single-bit quantization threshold amplitude according to the Rayleigh distribution parameters and the recoverable interval width parameter, and calculating a quantization threshold signal according to the single-bit quantization threshold amplitude and the quantization threshold frequency specifically includes: Transmitting a preset number of test pulse signals through a radar transmitter, and receiving a test echo signal returned after the test pulse signal is transmitted; Performing modulus processing and averaging processing on the test echo signal to obtain Rayleigh distribution parameters; The single-bit quantization threshold amplitude is calculated according to the Rayleigh distribution parameter and the recoverable interval width parameter, wherein the expression of the single-bit quantization threshold amplitude is: ； in, is the single-bit quantization threshold amplitude, is the Rayleigh distribution parameter, is the recoverable interval width parameter; Calculating a quantization threshold signal according to the single-bit quantization threshold amplitude and the quantization threshold frequency; The expression of the quantization threshold signal is: ； in, To quantize the threshold signal, is an exponential function, is an imaginary unit, To quantize the threshold frequency, Slow time for radar; The target radar image generation module is used to obtain a simulated echo signal, and perform single-bit quantization processing and matched filtering processing on the simulated echo signal according to the quantization threshold signal to obtain a target radar image.

6. A terminal, characterized in that: The terminal includes: a memory, a processor, and a single-bit synthetic aperture radar imaging program based on a slow time fluctuation threshold stored in the memory and executable on the processor. When the single-bit synthetic aperture radar imaging program based on a slow time fluctuation threshold is executed by the processor, the steps of the single-bit synthetic aperture radar imaging method based on a slow time fluctuation threshold as described in any one of claims 1 to 4 are implemented.

7. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a single-bit synthetic aperture radar imaging program based on a slow-time fluctuation threshold. When the single-bit synthetic aperture radar imaging program based on a slow-time fluctuation threshold is executed by a processor, the steps of the single-bit synthetic aperture radar imaging method based on a slow-time fluctuation threshold as described in any one of claims 1 to 4 are implemented.

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