Echo processing and motion parameter estimation method and device for uniformly accelerated moving target

Abstract

The invention discloses a uniformly accelerated motion target echo processing and motion parameter estimation method and device. The method comprises the following steps: acquiring a frequency coding signal target echo of a uniformly accelerated motion target; performing baseband echo processing to obtain echo after pulse compression; distance compensation and frequency domain transformation processing are carried out, and echoes after fast time Fourier transformation are obtained; second-order non-standard Keystone transformation processing is carried out, and a second-order non-standard transformation signal is obtained; performing acceleration estimation and compensation processing to obtain compensation echoes; performing first-order non-standard Keystone transformation processing to obtain a first-order non-standard transformation signal; echo phase-coherent accumulation processing is carried out, and echoes after phase-coherent accumulation are obtained; motion parameter estimation is carried out to obtain a motion parameter estimation result, and the motion parameter estimation result comprises the target initial distance and the target speed. According to the invention, echo processing and motion parameter estimation are realized, the estimation accuracy is improved, and the processing calculation amount is reduced. The method can be widely applied to the technical field of radar signal processing.

Description

Technical Field

[0001] The present invention relates to the technical field of radar signal processing, and in particular, to a method and device for processing the echo of a uniformly accelerated moving target and estimating its motion parameters. Background Art

[0002] As a radio detection device, radar plays an important role in target detection. In order to identify the motion state of a uniformly accelerated moving target during the detection process, the radar system designs an integrated detection and identification waveform based on frequency coding to achieve the integration of detection and identification functions. Traditional detection and identification methods process the echo of the target by combining the compressed sensing algorithm to estimate the target motion parameters. However, the carrier frequency of the frequency-coded signal is constantly hopping, and there is a problem of cross-range gates, resulting in a large amount of calculation for echo processing and low accuracy of motion parameter estimation.

[0003] In summary, the technical problems existing in the related art need to be improved. Summary of the Invention

[0004] Embodiments of the present invention provide a method and device for processing the echo of a uniformly accelerated moving target and estimating its motion parameters, effectively improving the estimation accuracy and reducing the processing calculation amount.

[0005] On the one hand, embodiments of the present invention provide a method for processing the echo of a uniformly accelerated moving target and estimating its motion parameters, including the following steps:

[0006] Obtain the frequency-coded signal target echo of the uniformly accelerated moving target;

[0007] Perform baseband echo processing on the frequency-coded signal target echo to obtain the echo after pulse compression;

[0008] Perform range compensation and frequency domain transformation processing on the echo after pulse compression to obtain the echo after fast-time Fourier transform;

[0009] Perform second-order non-standard Keystone transform processing on the echo after fast-time Fourier transform to obtain a second-order non-standard transform signal;

[0010] Perform acceleration estimation and compensation processing according to the second-order non-standard transform signal and the echo after fast-time Fourier transform to obtain a compensated echo;

[0011] Perform first-order non-standard Keystone transform processing on the compensated echo to obtain a first-order non-standard transform signal;

[0012] Perform echo coherent integration processing on the first-order non-standard transform signal to obtain the echo after coherent integration;

[0013] Based on the echo after coherent accumulation, motion parameter estimation is performed to obtain a motion parameter estimation result, where the motion parameter estimation result includes the target initial distance and the target velocity.

[0014] In some embodiments, the processing of the target echo of the frequency-coded signal to obtain the echo after pulse compression includes:

[0015] Performing down-conversion low-pass filtering on the target echo of the frequency-coded signal to obtain a baseband echo, where the down-conversion low-pass filtering is used to eliminate the high-frequency carrier frequency component in the target echo of the frequency-coded signal;

[0016] Performing frequency-domain pulse compression processing on the baseband echo along the fast time to obtain the echo after pulse compression.

[0017] In some embodiments, the processing of the echo after pulse compression to obtain the echo after fast-time Fourier transform includes:

[0018] Performing distance compensation processing on the echo after pulse compression to obtain an echo after distance compensation, where the distance compensation processing is used to eliminate the phase term in the echo after pulse compression;

[0019] According to the corresponding relationship of fast-time sampling points, performing Fourier transform processing on the echo after distance compensation along the fast time to obtain the echo after fast-time Fourier transform.

[0020] In some embodiments, the processing of the echo after fast-time Fourier transform to obtain a second-order non-standard Keystone transform signal includes:

[0021] Constructing a first fast-time frequency and slow-time coupling term according to the imaginary unit, reference frequency, frequency hopping interval, frequency coding sequence, target radial acceleration, wavelength, and slow time;

[0022] Decoupling the first fast-time frequency and slow-time coupling term to obtain a first decoupled signal;

[0023] Calculating a first virtual slow time according to the first decoupled signal;

[0024] Calculating the second-order non-standard transform signal according to the first virtual slow time and the echo after fast-time Fourier transform.

[0025] In some embodiments, the acceleration estimation and compensation processing based on the second-order non-standard transform signal and the echo after fast-time Fourier transform to obtain a compensated echo includes:

[0026] Defining an acceleration compensation function;

[0027] Calculate the acceleration estimation value according to the acceleration compensation function and the second-order non-standard transformation signal;

[0028] Construct a fast-time Fourier compensation function according to the acceleration estimation value;

[0029] Compensate the echo after fast-time Fourier transform according to the fast-time Fourier compensation function and the acceleration estimation value to obtain the compensated echo.

[0030] In some embodiments, the performing a first-order non-standard Keystone transform process on the compensated echo to obtain a first-order non-standard transformation signal includes:

[0031] Construct a second fast-time frequency and slow-time coupling term according to the imaginary unit, the target radial velocity, the reference frequency, the frequency hopping interval, the frequency coding sequence, the wavelength, and the slow time;

[0032] Decouple the second fast-time frequency and slow-time coupling term to obtain a second decoupled signal;

[0033] Calculate a second virtual slow time according to the second decoupled signal;

[0034] Calculate the first-order non-standard transformation signal according to the second virtual slow time and the compensated echo.

[0035] In some embodiments, the performing an echo coherent integration process on the first-order non-standard transformation signal to obtain a coherently integrated echo includes:

[0036] Perform an inverse Fourier transform on the first-order non-standard transformation signal along the fast-time frequency to obtain an echo after target range migration correction;

[0037] Perform a Fourier transform on the echo after target range migration correction along the virtual slow time to obtain the coherently integrated echo.

[0038] In some embodiments, the expression of the coherently integrated echo is:

[0039]

[0040] In the formula, is the coherently integrated echo, t is the fast time, f b is the virtual slow time frequency, T p is the pulse width of the chirp signal, c is the speed of light, B is the chirp signal bandwidth, R0 is the initial target radial distance, M is the number of coherent integrations, T r is the pulse repetition period, v0 is the target radial velocity, and λ is the wavelength.

[0041] On the other hand, an embodiment of the present invention provides an echo processing and motion parameter estimation device for a uniformly accelerated moving target, including:

[0042] A first module, configured to obtain the frequency-coded signal target echo of the uniformly accelerated moving target;

[0043] A second module, configured to perform baseband echo processing on the frequency-coded signal target echo to obtain the echo after pulse compression;

[0044] A third module, configured to perform range compensation and frequency-domain transformation processing on the echo after pulse compression to obtain the echo after fast-time Fourier transform;

[0045] A fourth module, configured to perform a second-order non-standard Keystone transform processing on the echo after fast-time Fourier transform to obtain a second-order non-standard transform signal;

[0046] A fifth module, configured to perform acceleration estimation and compensation processing according to the second-order non-standard transform signal and the echo after fast-time Fourier transform to obtain a compensated echo;

[0047] A sixth module, configured to perform a first-order non-standard Keystone transform processing on the compensated echo to obtain a first-order non-standard transform signal;

[0048] A seventh module, configured to perform echo coherent integration processing on the first-order non-standard transform signal to obtain the echo after coherent integration;

[0049] An eighth module, configured to perform motion parameter estimation according to the echo after coherent integration to obtain a motion parameter estimation result, where the motion parameter estimation result includes the target initial distance and the target velocity.

[0050] On the other hand, an embodiment of the present invention provides a computer device, including:

[0051] At least one processor;

[0052] At least one memory, configured to store at least one program;

[0053] When the at least one program is executed by the at least one processor, the at least one processor implements the method.

[0054] On the other hand, an embodiment of the present invention provides a computer-readable storage medium, where the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the method is implemented.

[0055] The beneficial effects of the present invention are as follows:

[0056] In the embodiment of the present invention, first, the frequency-coded signal target echo of a uniformly accelerated moving target is acquired, and the baseband echo processing is performed on the frequency-coded signal target echo to obtain the echo after pulse compression. Then, the range compensation and frequency-domain transformation processing are performed on the echo after pulse compression to obtain the echo after fast-time Fourier transform. The second-order non-standard Keystone transformation processing is performed on the echo after fast-time Fourier transform to obtain the second-order non-standard transformation signal. Then, based on the second-order non-standard transformation signal and the echo after fast-time Fourier transform, the acceleration estimation and compensation processing are performed to obtain the compensated echo. The first-order non-standard Keystone transformation processing is performed on the compensated echo to obtain the first-order non-standard transformation signal. The echo coherent integration processing is performed on the first-order non-standard transformation signal to obtain the echo after coherent integration. Finally, based on the echo after coherent integration, the motion parameter estimation is performed to obtain the motion parameter estimation result, thereby realizing the echo processing and motion parameter estimation, improving the estimation accuracy, and reducing the processing calculation amount.

[0057] Other features and advantages of the present invention will be described in the following specification, and, in part, will be obvious from the specification, or will be understood by implementing the present invention. The objectives and other advantages of the present invention can be realized and obtained by the structures specifically pointed out in the specification and the drawings. Brief Description of the Drawings

[0058] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0059] Figure 1 It is a flowchart of a method for processing the echo of a uniformly accelerated moving target and estimating motion parameters in an embodiment of the present invention;

[0060] Figure 2 It is a schematic diagram of the result of the echo after coherent integration in an embodiment of the present invention;

[0061] Figure 3 It is a schematic diagram of the overall process of echo processing and parameter estimation in an embodiment of the present invention;

[0062] Figure 4 It is a schematic diagram of the structure of a device for processing the echo of a uniformly accelerated moving target and estimating motion parameters in an embodiment of the present invention;

[0063] Figure 5 It is a schematic diagram of the hardware structure of a computer device in an embodiment of the present invention. Detailed Embodiments

[0064] In order to make the objectives, technical solutions and advantages of the present application more clear and understandable, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application. When the following description refers to the accompanying drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the embodiments of the present application. They are only examples of devices and methods consistent with some aspects of the embodiments of the present application as detailed in the appended claims.

[0065] It can be understood that the terms "first", "second", etc. used in the present application may be used herein to describe various concepts, but unless otherwise specified, these concepts are not limited by these terms. These terms are only used to distinguish one concept from another. For example, without departing from the scope of the embodiments of the present application, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Depending on the context, the words "if", "when" as used herein may be interpreted as "when...", "while...", or "in response to determining".

[0066] The terms "at least one", "a plurality of", "each", "any one", etc. used in the present application, at least one includes one, two or more than two, a plurality includes two or more than two, each refers to each one of the corresponding plurality, and any one refers to any one of the plurality.

[0067] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which this application belongs. The terms used herein are only for the purpose of describing the embodiments of this application and are not intended to limit this application.

[0068] Before elaborating on the embodiments of the present application in detail, some nouns and terms involved in the embodiments of the present application will be described first. The nouns and terms involved in the embodiments of the present application are subject to the following explanations.

[0069] Non-standard Keystone Transform (NST): It is an algorithm used for radar signal processing, mainly used to correct the target range walk phenomenon and improve the accuracy of radar target detection and positioning. Its basic principle is to convert the received radar signal from the frequency domain to the Keystone spectrum, and then perform time migration correction to eliminate the influence of range migration.

[0070] Fourier transform: It is a mathematical operation with wide application value in various fields such as mathematics, physics, computer science, and engineering. It is extended from the Fourier series and describes the amplitudes of sine or cosine functions with different frequencies contained in a function. In a specific function space, the Fourier transform of a function has good properties. For example, it can achieve the mutual conversion of differentiation and polynomial multiplication, the mutual conversion of function convolution and multiplication, etc., and thus can be used to solve partial differential equations, norm control, prove inequalities, etc.

[0071] In related technologies, as a radio detection device, radar has the advantages of all-weather, all-day operation, and strong penetration ability. It plays a crucial role in both military and disaster relief and civilian applications. In modern technology-based military, radar faces unprecedented strong threats. The rapid development of high-sensitivity radar signal interception technology makes most radars at risk of being exposed as soon as they are turned on, increasing the probability of mission failure. Therefore, how to reduce the probability of one's own radar being detected and intercepted while quickly obtaining battlefield intelligence is an urgent problem to be solved. Identification friend or foe is a series of actions carried out by both sides in military confrontation to obtain information such as the type, affiliation, threat level, and friend or foe of targets on the battlefield in order to control the military situation. With the transformation of military confrontation methods, especially the development of electronic warfare, information warfare, and cyber warfare, the requirements for target identification friend or foe are also increasing day by day. Currently, the overall trend of the integrated development of military equipment is prominent and significantly accelerating. The task requirement of the tight coupling of detection and identification puts forward higher requirements for the integration of the two systems. In order to alleviate the problem of the increasingly scarce spectrum resources, related technologies have proposed the concept of a multi-functional integrated system. With the progress of electronic information technology, the differences between radar systems and communication systems are gradually decreasing, and the joint radar communication system based on hardware devices and integrated signals has attracted wide attention. One of the effective methods to establish a joint radar communication system is to design a dual-functional waveform. Specifically, for a dual-functional waveform whose main function is radar and the second function is communication, the goal can be achieved through time-division multiplexing, frequency-division multiplexing, and code-division multiplexing. However, this kind of multiplexing still has limitations in efficiency and resources for the detection and identification integrated system and is difficult to fully meet the requirements of detection and identification integration.

[0072] Therefore, traditional methods have designed an integrated detection and recognition waveform based on frequency coding. This waveform can embed recognition information into the frequency-coded waveform transmitted by the radar through coding rules, thus truly achieving the sharing of detection and recognition. The recognition device at the target end receives the integrated signal transmitted by the radar, analyzes its coding rules, extracts the interrogation information from the radar end, generates a corresponding response frequency-coded signal according to the interrogation information and forwards it. After receiving the scattered echo of the target and the recognition forwarding signal, the radar receiving end performs integrated processing to finally achieve the functional integration of detection and recognition. However, different from the commonly used single-frequency or linear frequency modulation signals in the past, the frequency hopping of the frequency-coded signal brings difficulties to signal processing, and some commonly used signal processing methods are not applicable, presenting challenges in target detection and parameter estimation. Since the target Doppler is related to the radial velocity and wavelength, the radar frequency hopping will affect its continuity in slow time, and thus coherent integration cannot be carried out using Moving Target Detection (MTD). For a narrowband fixed-carrier-frequency radar, the slow time of the target echo is approximately a single-frequency signal. For a frequency-coded radar, due to the coupling of the coded frequency with the target distance and motion parameters, the slow-time signal form of the target echo is complex, and coherent integration cannot be achieved using the Fast Fourier Transform (FFT) or the Fractional Fourier Transform (FrFT). From the perspective of target detection, for a known signal form, matched filtering is the optimal detection method. The target echo of a frequency-coded radar can be understood as a signal with partial known information (the frequency coding is known, but the target distance and motion parameters are unknown). Therefore, a "distance-motion parameter" search interval can be set, and then a corresponding matched signal can be constructed to cyclically search for the maximum correlation peak to achieve coherent integration. The disadvantage is that the computational complexity of the cyclic search is relatively large. These mainstream ideas usually combine many Compressing Sensing (CS) algorithms to sparsely reconstruct the target, and the atoms constructed therein are the matched signals mentioned above. In addition, there is another idea for a uniformly moving target, which is to divide the slow-time signal of the echo into a distance term and a velocity term, first compensate the distance term, and then perform a non-uniform Fast Fourier Transform (NUFFT) on the velocity term. However, neither of these two ideas considers the problem of cross-range cell migration that is prone to occur in high-speed moving targets. In response to this situation, the Keystone Transform (KT) is proposed to correct the target range migration, but the standard KT virtual slow time is constructed as The carrier frequency is fixed, while the carrier frequency of frequency coding is constantly hopping. Therefore, the standard KT is not applicable to frequency-coded radars, and a non-standard Keystone transform needs to be further constructed for frequency-coded radars to correct the target range migration.

[0073] In view of this, in this embodiment, according to the requirements of target detection and parameter estimation, two non-standard Keystone transforms are performed at the radar receiving end according to the characteristics of the frequency-coded signal to achieve target range migration correction, thereby effectively coherently accumulating the target echo. And through the search compensation process, the estimated values of parameters such as the target initial range, velocity, and acceleration are obtained, thus realizing echo processing and motion parameter estimation, improving the estimation accuracy, and reducing the processing calculation amount.

[0074] A method for processing the echo of a uniformly accelerating moving target and estimating motion parameters provided by an embodiment of the present application relates to the technical field of radar signal processing. The method for processing the echo of a uniformly accelerating moving target and estimating motion parameters provided by an embodiment of the present application can be applied to a terminal, or can be applied to a server, or can also be software running on a terminal or a server. In some embodiments, the terminal can be a smart phone, a tablet computer, a notebook computer, a desktop computer, a smart speaker, a smart watch, a vehicle-mounted terminal, etc., but is not limited thereto; the server side can be configured as an independent physical server, or can be configured as a server cluster or distributed system composed of multiple physical servers, or can also be configured as a cloud server providing basic cloud computing services such as cloud services, cloud databases, cloud computing, cloud functions, cloud storage, network services, cloud communications, middleware services, domain name services, security services, CDN, and big data and artificial intelligence platforms. The server can also be a node server in a blockchain network; the software can be an application implementing a method for processing the echo of a uniformly accelerating moving target and estimating motion parameters, etc., but is not limited to the above forms.

[0075] The present application can be used in many general or special computer system environments or configurations. For example: personal computers, server computers, handheld or portable devices, tablet-type devices, multi-processor systems, microprocessor-based systems, set-top boxes, programmable consumer electronics devices, network PCs, minicomputers, mainframe computers, distributed computing environments including any of the above systems or devices, and so on. The present application can be described in the general context of computer-executable instructions executed by a computer, such as program modules. Generally, program modules include routines, programs, objects, components, data structures, etc. that perform specific tasks or implement specific abstract data types. The present application can also be practiced in a distributed computing environment where tasks are performed by remote processing devices connected through a communication network. In a distributed computing environment, program modules can be located in local and remote computer storage media including storage devices.

[0076] The embodiments of the present application will be specifically explained below with reference to the accompanying drawings:

[0077] Figure 1 is an optional flowchart of a method for processing the echo of a uniformly accelerated moving target and estimating motion parameters provided by the embodiments of the present application. Figure 1 The method in may include but is not limited to steps S101 to S108.

[0078] Step S101: Obtain the frequency-coded signal target echo of the uniformly accelerated moving target;

[0079] Step S102: Perform baseband echo processing on the frequency-coded signal target echo to obtain the echo after pulse compression;

[0080] Step S103: Perform range compensation and frequency-domain transformation processing on the echo after pulse compression to obtain the echo after fast-time Fourier transform;

[0081] Step S104: Perform second-order non-standard Keystone transform processing on the echo after fast-time Fourier transform to obtain a second-order non-standard transform signal;

[0082] Step S105: Perform acceleration estimation and compensation processing based on the second-order non-standard transform signal and the echo after fast-time Fourier transform to obtain a compensated echo;

[0083] Step S106: Perform first-order non-standard Keystone transform processing on the compensated echo to obtain a first-order non-standard transform signal;

[0084] Step S107: Perform echo coherent integration processing on the first-order non-standard transform signal to obtain the echo after coherent integration;

[0085] Step S108: Perform motion parameter estimation based on the echo after coherent integration to obtain a motion parameter estimation result, where the motion parameter estimation result includes the target initial distance and the target velocity.

[0086] Steps S101 to S108 illustrated in the embodiments of the present application achieve echo processing and motion parameter estimation, improve the estimation accuracy, and reduce the processing calculation amount.

[0087] In step S101 of some embodiments, the frequency-coded signal target echo of a uniformly accelerated moving target can be obtained through radar reception. It can also be obtained by other means, and is not limited thereto. Exemplarily, under narrowband conditions, a frequency-coded radar emits a linear frequency modulation (LFM) pulse signal, and the radar receives the radio frequency echo of a uniformly accelerated moving point target, that is, the frequency-coded signal target echo modulated by the linear frequency modulation signal. Among them, the expression of the frequency-coded signal target echo is: In the formula, s R is the frequency-coded signal target echo, t is the fast time, t m = mT r , m = 0, 1, …, M-1, M is the number of coherent integrations, T r is the pulse repetition period, t m is the slow time, rect[*] is the unit rectangular function, exp(*) is the exponential function, T p is the pulse width of the linear frequency modulation signal, R0 is the initial radial distance of the target, v0 is the radial velocity of the target, a0 is the radial acceleration of the target, j is the imaginary unit, μ is the frequency modulation slope, B is the bandwidth of the linear frequency modulation signal, c is the speed of light, f c is the reference frequency, {c m} is the frequency-coded sequence, and Δf is the frequency hopping interval.

[0088] In some embodiments, in step S102, the baseband echo processing of the frequency-coded signal target echo to obtain the echo after pulse compression may include but is not limited to the following steps:

[0089] Perform down-conversion low-pass filtering on the frequency-coded signal target echo to obtain the baseband echo. The down-conversion low-pass filtering is used to eliminate the high-frequency carrier frequency component in the frequency-coded signal target echo;

[0090] Perform frequency-domain pulse compression processing on the baseband echo along the fast time to obtain the echo after pulse compression.

[0091] In some embodiments, the frequency-coded signal target echo can be first subjected to down-conversion low-pass filtering to obtain the baseband echo, where the down-conversion low-pass filtering is used to eliminate the high-frequency carrier frequency component exp(j2π(f c +c m Δf)t) in the frequency-coded signal target echo. The expression of the baseband echo is: In the formula, s rIs the baseband echo. The down-conversion low-pass filtering process can effectively eliminate the high-frequency carrier frequency components. Then, the baseband echo is subjected to frequency-domain pulse compression processing along the fast time to obtain the echo after pulse compression. Exemplarily, when B·T p >> 1, the result of the rectangular pulse echo of the chirp signal after pulse compression processing can be approximated as a sinc[*] function, and the echo after pulse compression can be approximately expressed as: In the formula, y s Is the echo after pulse compression, and the peak position of the sinc[*] function is: When the movement amount is greater than one fast-time sampling period, range migration of the target will occur.

[0092] In some embodiments, in step S103, performing range compensation and frequency-domain transformation processing on the echo after pulse compression to obtain the echo after fast-time Fourier transform may include, but is not limited to, the following steps:

[0093] Performing range compensation processing on the echo after pulse compression to obtain the echo after range compensation, and the range compensation processing is used to eliminate the phase term in the echo after pulse compression;

[0094] According to the fast-time sampling point correspondence, performing Fourier transform processing on the echo after range compensation along the fast time to obtain the echo after fast-time Fourier transform.

[0095] In some embodiments, the echo after pulse compression may be first subjected to range compensation processing to obtain the echo after range compensation, where the range compensation processing is used to eliminate the Phase term, and the expression of the echo after range compensation is: In the formula, Is the echo after range compensation. Since the true range of the target is usually unknown, range search is required. And there is Correspondence at the fast-time sampling points, and the actual range compensation process can be achieved through Realize. According to the fast-time sampling point correspondence, performing Fourier transform processing on the echo after range compensation along the fast time to obtain the echo after fast-time Fourier transform, where the expression of the echo after fast-time Fourier transform is: In the formula, β(f,t m ) is the echo after fast-time Fourier transform, f is the fast-time frequency corresponding to the fast time t, λ is the wavelength.

[0097] In some embodiments, in step S104, performing second-order non-standard Keystone transform processing on the echo after fast-time Fourier transform to obtain a second-order non-standard transform signal may include, but is not limited to, the following steps:

[0098] Construct a first fast-time frequency and slow-time coupling term according to the imaginary unit, reference frequency, frequency hopping interval, frequency coding sequence, target radial acceleration, wavelength, and slow time;

[0099] Decouple the first fast-time frequency and slow-time coupling term to obtain a first decoupled signal;

[0100] Calculate a first virtual slow time according to the first decoupled signal;

[0101] Calculate a second-order non-standard transform signal according to the first virtual slow time and the echo after fast-time Fourier transform.

[0102] In some embodiments, first, a first fast-time frequency and slow-time coupling term may be constructed according to the imaginary unit, reference frequency, frequency hopping interval, frequency coding sequence, target radial acceleration, wavelength, and slow time. Exemplarily, for a frequency-coded radar, the expression of the first fast-time frequency and slow-time coupling term containing the acceleration phase is: In the formula, is the first fast-time frequency and slow-time coupling term. Then, decouple the first fast-time frequency and slow-time coupling term to obtain a first decoupled signal, where the expression of the first decoupled signal is: In the formula, is the first decoupled signal. Then, calculate a first virtual slow time according to the first decoupled signal, where the expression of the first virtual slow time is: In the formula, t a is the first virtual slow time. It can be understood that can be understood as a discrete sampling sequence obtained from the same signal at different sampling times, where is equidistant sampling, and the sampling time is t1 = t m , is non-equidistant sampling, and the sampling time is Therefore, an approximate form obtained by interpolation can be used to achieve decoupling of the fast-time frequency and slow time, that is: is a known signal at the sampling time At the sampling time t1 = t m re-interpolate to obtain ​As a result, t2 is used as the first virtual slow time. It can be understood that interp[*] is an interpolation symbol, and common interpolation methods include Linear Interpolation (LI), Nearest Neighbor Interpolation (NNI), Spline Interpolation (SI), Piecewise Cubic Hermite Polynomial Interpolation (PCHIP), etc. In actual situations, affected by factors such as the time distribution characteristics of the sequence before interpolation, there will be a certain error between the interpolated sequence and the ideal state, which will in turn lead to higher sidelobes in the target echo after coherent accumulation. This problem can be weakened by improving the interpolation algorithm, but it cannot be avoided. It should be noted that the interpolation function in MATLAB software requires the signal time before interpolation to be increasing, but affected by the frequency encoding c m influence, t2 is not necessarily increasing. When t2 is non-increasing, it is necessary to rearrange the signals according to the increasing time relationship and then perform interpolation processing. Finally, according to the first virtual slow time and the echo after fast-time Fourier transform, the second-order non-standard transform signal is calculated. Among them, the expression of the second-order non-standard transform signal is: In the formula, is the second-order non-standard transform signal. It can be understood that the second-order non-standard Keystone transform can be realized by signal interpolation.

[0103] In some embodiments, in step S105, according to the second-order non-standard transform signal and the echo after fast-time Fourier transform, acceleration estimation and compensation processing are performed to obtain a compensated echo, which may include but is not limited to the following steps:

[0104] Define an acceleration compensation function;

[0105] Calculate the acceleration estimation value according to the acceleration compensation function and the second-order non-standard transform signal;

[0106] Construct a fast-time Fourier compensation function according to the acceleration estimation value;

[0107] Compensate the echo after fast-time Fourier transform according to the fast-time Fourier compensation function and the acceleration estimation value to obtain a compensated echo.

[0108] In some embodiments, the acceleration compensation function can be defined first. Among them, the expression of the acceleration compensation function is: In the formula, is the acceleration compensation function, a1 is the acceleration value used for search compensation, and the search range is [a min , a max , a minis the minimum possible acceleration, a max is the maximum possible acceleration, a1 ∈ [a mun , a max . Then, according to the acceleration compensation function and the second-order non-standard transformation signal, the acceleration estimate value is calculated. Among them, the calculation formula of the acceleration estimate value is: In the formula, is the acceleration estimate value. It should be noted that since the target energy is still not concentrated in a certain range-frequency unit at this time, but is scattered within the signal bandwidth, it is necessary to estimate the acceleration for all range-frequency units within the signal bandwidth, and average a series of obtained accelerations to obtain the acceleration estimate value. Then, according to the acceleration estimate value, a fast-time Fourier compensation function is constructed. Among them, the expression of the fast-time Fourier compensation function is: In the formula, M a (t m ) is the fast-time Fourier compensation function. Finally, according to the fast-time Fourier compensation function and the acceleration estimate value, the echo after the fast-time Fourier transform is compensated to obtain the compensated echo. Among them, the expression of the compensated echo is: In the formula, is the compensated echo. At this time, the acceleration phase term is compensated, and the obtained compensated echo can be regarded as the echo of a uniformly moving target.

[0109] In some embodiments, in step S106, the first-order non-standard Keystone transform process is performed on the compensated echo to obtain the first-order non-standard transform signal, which may include but is not limited to the following steps:

[0110] Construct the second fast-time frequency and slow-time coupling term according to the imaginary unit, the target radial velocity, the reference frequency, the frequency hopping interval, the frequency coding sequence, the wavelength, and the slow time;

[0111] Decouple the second fast-time frequency and slow-time coupling term to obtain the second decoupled signal;

[0112] Calculate the second virtual slow time according to the second decoupled signal;

[0113] Calculate the first-order non-standard transform signal according to the second virtual slow time and the compensated echo.

[0114] In some embodiments, the second fast-time frequency and slow-time coupling term can be constructed first according to the imaginary unit, the target radial velocity, the reference frequency, the frequency hopping interval, the frequency coding sequence, the wavelength, and the slow time. Among them, the expression of the second fast-time frequency and slow-time coupling term is: In the formula, is the coupling term of the second-fastest time frequency and the slow time. Then, decoupling is performed on the coupling term of the second-fastest time frequency and the slow time to obtain a second decoupled signal. The expression of the second decoupled signal is as follows: In the formula, is the second decoupled signal. Then, based on the second decoupled signal, a second virtual slow time is calculated. The expression of the second virtual slow time is as follows: In the formula, t b is the second virtual slow time. It can be understood that can be understood as the discrete sampling sequence obtained by the same signal at different sampling times, where is equidistant sampling, and the sampling time is t3 = t m , is non-equidistant sampling, and the sampling time is Therefore, an approximate form obtained by interpolation can be used to achieve decoupling of the fast time frequency and the slow time, that is: is the signal with the known sampling time at the sampling time t3 = t m and re-interpolation is performed to obtain The result of can be used as the second virtual slow time. Finally, based on the second virtual slow time and the compensated echo, a first-order non-standard transform signal is calculated. The expression of the first-order non-standard transform signal is as follows: In the formula, is the first-order non-standard transform signal. It can be understood that the first-order non-standard Keystone transform can be achieved by signal interpolation.

[0115] In some embodiments, in step S107, performing echo coherent accumulation processing on the first-order non-standard transform signal to obtain the coherent-accumulated echo may include, but is not limited to, the following steps:

[0116] Performing an inverse Fourier transform on the first-order non-standard transform signal along the fast time frequency to obtain the echo after target range migration correction;

[0117] Performing a Fourier transform on the echo after target range migration correction along the virtual slow time to obtain the coherent-accumulated echo.

[0118] In some embodiments, an inverse Fourier transform may be first performed on the first-order non-standard transform signal along the fast time frequency to obtain the echo after target range migration correction. The expression of the echo after target range migration correction is as follows: In the formula, ​is the echo after target range migration correction. Then, the echo after target range migration correction is Fourier-transformed along the virtual slow time to obtain the coherently integrated echo. The expression of the coherently integrated echo is as follows: In the formula, is the coherently integrated echo, t is the fast time, f b is the virtual slow time frequency, T p is the pulse width of the chirp signal, c is the speed of light, B is the bandwidth of the chirp signal, R0 is the initial target radial distance, M is the number of coherent integrations, T r is the pulse repetition period, v0 is the target radial velocity, and λ is the wavelength.

[0119] In some embodiments, in step S108, motion parameter estimation can be performed based on the coherently integrated echo to obtain the motion parameter estimation result. The motion parameter estimation result includes the target initial distance and the target velocity. Exemplarily, the target can be detected from the result graph of the coherently integrated echo. The target peak position in the coherently integrated echo is By converting the coordinate axes according to the corresponding relationship, we get: Thus, the target initial distance and the target velocity can be obtained from the peak position.

[0120] In some embodiments, experimental analysis can be performed to verify the estimation accuracy of the method in this embodiment through simulation data. The software MATLAB R2024b can be used for data simulation experiments. The computer generates the target echo of the frequency-coded signal of a uniformly accelerated moving target modulated by a chirp signal, and successively performs the processing procedures of baseband echo processing, range compensation and frequency domain transformation, second-order non-standard Keystone transformation, acceleration estimation and compensation, first-order non-standard Keystone transformation, echo coherent integration and parameter estimation. Finally, the results are shown in a graph. The simulation parameter settings include: the initial target radial distance is R0 = 1500m, the target radial velocity is the target radial acceleration is The acceleration estimation value obtained after performing the acceleration estimation process is which is close to the actual value a0. The schematic diagram of the result of the coherently integrated echo obtained after simulation is as Figure 2 shown. It can be seen that the range migration of the target echo is corrected, the echo achieves effective coherent integration, the target peak is clear, and the parameter estimation values corresponding to the target peak are the target initial distance the target velocity both of which are close to the actual values R0 and v0. Figure 2 In the figure, the abscissa X of the target peak position corresponds to the initial distance, and the ordinate Y corresponds to the target velocity. Since the target acceleration is estimated and compensated in advance in this embodiment, the target has been simplified to a uniformly moving target, Figure 2The estimated target motion parameters only include the target initial distance and the target velocity.

[0121] In some embodiments, the overall process of echo processing and parameter estimation is as Figure 3 shown. First, the frequency-coded signal target echo of a uniformly accelerated moving target can be obtained through the radar receiving end, and then baseband echo processing is performed, including down-conversion, low-pass filtering, and pulse compression. Distance compensation and frequency-domain transformation are carried out, including distance compensation and fast-time Fourier transform. Second-order non-standard Keystone transformation is performed. Velocity estimation and compensation are carried out, including acceleration estimation and acceleration compensation. First-order non-standard Keystone transformation is performed. Echo coherent accumulation and parameter estimation are carried out, including fast-time inverse Fourier transform and slow-time Fourier transform, to obtain the echo after coherent accumulation.

[0122] In some embodiments, this embodiment has a smaller computational load compared with the distance-velocity-acceleration three-dimensional joint search scheme, and can better meet the real-time requirement while obtaining the target motion parameters. By performing two non-standard Keystone transformations at the radar receiving end according to the characteristics of the frequency-coded signal, the range migration correction and coherent accumulation of the target echo are effectively realized, the detection and motion parameter estimation of the target are completed, and the problem of echo signal processing and parameter estimation of the frequency-coded signal for a uniformly accelerated moving target is effectively solved.

[0123] The beneficial effects of implementing the embodiments of the present invention include: The embodiments of the present invention first obtain the frequency-coded signal target echo of a uniformly accelerated moving target, perform baseband echo processing on the frequency-coded signal target echo to obtain the echo after pulse compression, then perform distance compensation and frequency-domain transformation processing on the echo after pulse compression to obtain the echo after fast-time Fourier transform, perform second-order non-standard Keystone transformation processing on the echo after fast-time Fourier transform to obtain the second-order non-standard transformation signal, then perform acceleration estimation and compensation processing according to the second-order non-standard transformation signal and the echo after fast-time Fourier transform to obtain the compensated echo, perform first-order non-standard Keystone transformation processing on the compensated echo to obtain the first-order non-standard transformation signal, perform echo coherent accumulation processing on the first-order non-standard transformation signal to obtain the echo after coherent accumulation, and finally perform motion parameter estimation according to the echo after coherent accumulation to obtain the motion parameter estimation result, thereby realizing echo processing and motion parameter estimation, improving the estimation accuracy, and reducing the processing computational load.

[0124] As Figure 4 shown, the embodiments of the present invention also provide a device for echo processing and motion parameter estimation of a uniformly accelerated moving target, including:

[0125] The first module 801 is used to obtain the frequency-coded signal target echo of a uniformly accelerated moving target;

[0126] The second module 802 is configured to perform baseband echo processing on the target echo of the frequency-coded signal to obtain the echo after pulse compression;

[0127] The third module 803 is configured to perform range compensation and frequency-domain transformation processing on the echo after pulse compression to obtain the echo after fast-time Fourier transform;

[0128] The fourth module 804 is configured to perform second-order non-standard Keystone transformation processing on the echo after fast-time Fourier transform to obtain a second-order non-standard transformation signal;

[0129] The fifth module 805 is configured to perform acceleration estimation and compensation processing according to the second-order non-standard transformation signal and the echo after fast-time Fourier transform to obtain a compensated echo;

[0130] The sixth module 806 is configured to perform first-order non-standard Keystone transformation processing on the compensated echo to obtain a first-order non-standard transformation signal;

[0131] The seventh module 807 is configured to perform echo coherent integration processing on the first-order non-standard transformation signal to obtain the echo after coherent integration;

[0132] The eighth module 808 is configured to perform motion parameter estimation according to the echo after coherent integration to obtain a motion parameter estimation result, where the motion parameter estimation result includes the target initial distance and the target velocity.

[0133] The content in the above method embodiments is applicable to the device embodiments. The functions specifically implemented in the device embodiments are the same as those in the above method embodiments, and the beneficial effects achieved are also the same as those in the above method embodiments.

[0134] As Figure 5 shown, an embodiment of the present invention further provides a computer device, including:

[0135] At least one processor 901;

[0136] At least one memory 902 for storing at least one program;

[0137] When at least one program is executed by at least one processor, at least one processor implements Figure 1 the method shown.

[0138] The content in the above method embodiments is applicable to the device embodiments. The functions specifically implemented in the device embodiments are the same as those in the above method embodiments, and the beneficial effects achieved are also the same as those in the above method embodiments.

[0139] An embodiment of the present invention also provides a computer-readable storage medium storing a computer program, which when executed by a processor implements Figure 1 the method shown.

[0140] The content in the above method embodiments is applicable to this storage medium embodiment. The functions specifically implemented by this storage medium embodiment are the same as those in the above method embodiments, and the beneficial effects achieved are also the same as those in the above method embodiments.

[0141] The preferred embodiments of the embodiments of the present application have been described above with reference to the accompanying drawings. This does not limit the scope of the rights of the embodiments of the present application. Any modifications, equivalent replacements, and improvements made by those skilled in the art without departing from the scope and essence of the embodiments of the present application shall fall within the scope of the rights of the embodiments of the present application.

Claims

1. A method for processing echoes and estimating motion parameters of a uniformly accelerated moving target, characterized in that: The following steps are involved: Acquire the frequency coded signal target echo of the uniformly accelerated moving target; Performing baseband echo processing on the frequency coded signal target echo to obtain a pulse compressed echo; Performing distance compensation and frequency domain transformation processing on the echo after the pulse compression to obtain an echo after fast time Fourier transformation; Performing a second-order non-standard Keystone transform on the echo after the fast-time Fourier transform to obtain a second-order non-standard transform signal; According to the second-order non-standard transformation signal and the echo after the fast-time Fourier transformation, acceleration estimation and compensation processing are performed to obtain a compensated echo; Performing a first-order non-standard Keystone transform on the compensation echo to obtain a first-order non-standard transformed signal; Performing echo coherent accumulation processing on the first-order non-standard transformed signal to obtain an echo after coherent accumulation; According to the echo after the coherent accumulation, motion parameter estimation is performed to obtain a motion parameter estimation result, and the motion parameter estimation result includes a target initial distance and a target speed.

2. The method according to claim 1, characterized in that The step of performing baseband echo processing on the frequency coded signal target echo to obtain a pulse compressed echo comprises: Performing down-conversion low-pass filtering on the frequency-coded signal target echo to obtain a baseband echo, wherein the down-conversion low-pass filtering is used to eliminate high-frequency carrier frequency components in the frequency-coded signal target echo; The baseband echo is subjected to frequency domain pulse compression processing along the fast time to obtain the echo after pulse compression.

3. The method according to claim 1, characterized in that The distance compensation and frequency domain transformation processing are performed on the echo after the pulse compression to obtain the echo after the fast time Fourier transformation, including: Performing distance compensation processing on the echo after the pulse compression to obtain a distance-compensated echo, wherein the distance compensation processing is used to eliminate a phase item in the echo after the pulse compression; According to the fast time sampling point correspondence, the distance compensated echo is subjected to Fourier transform processing along the fast time to obtain the fast time Fourier transformed echo.

4. The method according to claim 1, characterized in that: The step of performing a second-order non-standard Keystone transform on the echo after the fast-time Fourier transform to obtain a second-order non-standard transformed signal includes: According to the imaginary unit, the reference frequency, the frequency hopping interval, the frequency coding sequence, the target radial acceleration, the wavelength and the slow time, the first fast time frequency and the slow time coupling term are constructed; Decoupling the first fast time frequency and the slow time coupling term to obtain a first decoupled signal; Calculating a first virtual slow time according to the first decoupling signal; The second-order non-standard transformation signal is calculated according to the first virtual slow time and the echo after the fast time Fourier transformation.

5. The method according to claim 1, characterized in that The method of performing acceleration estimation and compensation processing according to the second-order non-standard transformation signal and the echo after the fast-time Fourier transformation to obtain a compensated echo includes: Define acceleration compensation function; Calculating an acceleration estimation value according to the acceleration compensation function and the second-order non-standard transformation signal; constructing a fast-time Fourier compensation function based on the acceleration estimate; The echo after the fast-time Fourier transform is compensated according to the fast-time Fourier compensation function and the acceleration estimation value to obtain the compensated echo.

6. The method according to claim 1, characterized in that The performing a first-order non-standard Keystone transform on the compensation echo to obtain a first-order non-standard transformed signal includes: According to the imaginary unit, the target radial velocity, the reference frequency, the frequency hopping interval, the frequency coding sequence, the wavelength and the slow time, the second fastest time frequency and the slow time coupling term are constructed; Decoupling the second fast time frequency and the slow time coupling term to obtain a second decoupled signal; calculating a second virtual slow time according to the second decoupling signal; The first-order non-standard transformation signal is calculated according to the second virtual slow time and the compensation echo.

7. The method according to claim 1, characterized in that The step of performing echo coherent accumulation processing on the first-order non-standard transformed signal to obtain an echo after coherent accumulation includes: Performing an inverse Fourier transform on the first-order non-standard transformation signal along a fast time frequency to obtain an echo corrected for target range migration; The echo after the target range migration correction is subjected to Fourier transformation along the virtual slow time to obtain the echo after the coherent accumulation.

8. The method according to claim 1, characterized in that The expression of the echo after the coherent accumulation is: In the formula, is the echo after the coherent accumulation, t is the fast time, f b is the virtual slow time frequency, T p is the linear frequency modulation signal pulse width, c is the speed of light, B is the linear frequency modulation signal bandwidth, R0 is the target radial initial distance, M is the number of coherent accumulation, T r is the pulse repetition period, v0 is the target radial velocity, and λ is the wavelength.

9. A device for processing echoes and estimating motion parameters of uniformly accelerated moving targets, characterized in that: include: The first module is used to obtain the frequency coded signal target echo of the uniformly accelerated moving target; The second module is used to perform baseband echo processing on the frequency coded signal target echo to obtain a pulse compressed echo; The third module is used to perform distance compensation and frequency domain transformation processing on the echo after the pulse compression to obtain the echo after fast time Fourier transformation; The fourth module is used to perform a second-order non-standard Keystone transform on the echo after the fast-time Fourier transform to obtain a second-order non-standard transformed signal; A fifth module is used to perform acceleration estimation and compensation processing according to the second-order non-standard transformation signal and the echo after the fast-time Fourier transformation to obtain a compensated echo; A sixth module is used to perform a first-order non-standard Keystone transform on the compensation echo to obtain a first-order non-standard transformed signal; The seventh module is used to perform echo coherent accumulation processing on the first-order non-standard transformation signal to obtain an echo after coherent accumulation; The eighth module is used to perform motion parameter estimation based on the echo after the coherent accumulation to obtain a motion parameter estimation result, wherein the motion parameter estimation result includes an initial target distance and a target speed.

10. A computer device, characterized in that: include: at least one processor; at least one memory for storing at least one program; When the at least one program is executed by the at least one processor, the at least one processor implements the method according to any one of claims 1 to 8.

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