Design method and device of radar MTI filter, and storage medium
By discretizing the response range of the radar MTI filter and optimizing it with derivative and L2 norm constraints, a filter with a deep and wide notch near the zero Doppler frequency was designed. This solves the problem of the inability to balance the depth and width of the notch in the existing technology and improves the radar detection performance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-04
- Publication Date
- 2026-03-10
AI Technical Summary
Existing radar MTI filters have notches that are too sharp or too wide near the zero Doppler frequency, making it difficult to simultaneously meet the depth and width requirements, and the width of the transition band is uncontrollable.
By discretizing the response range of the MTI filter into a passband and a transition band, setting the filter order N, and applying derivative and 2-norm constraints, the passband flatness is minimized, and the filter coefficients are optimized to achieve a controllable transition band width.
While ensuring the depth of the notch, the notch width for ground clutter was expanded, and the steepness of the transition zone was controlled, thereby improving the radar detection signal-to-noise ratio.
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Figure CN121634003A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the radar detection technical field, especially to a radar MTI filter design method and device, and a storage medium. BACKGROUND
[0002] The MTI (Moving Target Indication) filter is a commonly used filter in ground-based early warning radar, which is mainly used to filter out ground clutter to improve the signal-to-noise ratio of moving target detection. Generally, we hope that the designed MTI filter has a relatively deep and wide notch near the zero Doppler frequency, and the transition bandwidth is controllable.
[0003] However, in engineering, the classic first-order canceller (filter coefficient is [1, -1]) or N-order mean canceller notch is too sharp, and it is difficult to deal with the relatively large fluctuation environment. The notch of the second-order canceller (filter coefficient is [1, -2, 1]) is too wide, and the attenuation of the desired target is too large. Therefore, a good performance MTI filter is crucial to the performance of the ground-based early warning radar. SUMMARY
[0004] The technical problem to be solved by the present application is to provide a radar MTI filter design method and device, and a storage medium, which can make the MTI filter have a relatively deep and wide notch near the zero Doppler frequency, and the transition bandwidth is controllable.
[0005] In order to solve the above technical problems, the first aspect of the present application discloses a radar MTI filter design method, comprising:
[0006] According to the response of the system in the static environment, the entire response interval of the MTI filter is divided into a passband and a transition band, and the passband and the transition band are discretized;
[0007] The order N of the MTI filter is set, and the passband flatness minimization is taken as the cost function;
[0008] The derivative constraint is applied to the response of the direct current position of the MTI filter, and / or the 2-norm constraint is applied to the transition band response of the MTI filter;
[0009] Solve the cost function, and take the optimal solution of the cost function as the coefficient of the MTI filter.
[0010] Optionally, after the entire response interval of the MTI filter is divided into a passband and a transition band, and the passband and the transition band are discretized, the method further comprises:
[0011] The frequency point set of the discretized passband is determined as , and the frequency point set of the discretized transition band is determined as ; wherein is the number of frequency points in the passband, is the number of frequency points in the transition band.
[0012] Optionally, the derivative constraint on the response of the MTI filter to the DC position comprises:
[0013] The derivative constraint on the response of the MTI filter to the DC position comprises one or more of a 0thorder to Dthorder derivative constraint, wherein D is less than N-2.
[0014] Optionally, the derivative constraint on the response of the MTI filter to the DC position and the 2-norm constraint on the response of the MTI filter to the transition band are applied in the following manner:
[0015] (1)
[0016] wherein, is the coefficient of the MTI filter, which is a column vector of length L; T is the vector transpose;
[0017] is a column vector of all ones of length L;
[0018] ; (2)
[0019] ; (3)
[0020] ; (4)
[0021] wherein, ; is the upper bound of the transition band 2-norm constraint;
[0022] ; (5)
[0023] is the D-1thderivative constraint vector of the vector e at frequency 0, wherein:
[0024] (6)
[0025] Optionally, the solving of the cost function and the optimal solution of the cost function as the coefficient of the MTI filter are in the following manner:
[0026] solving the following formula:
[0027]
[0028] wherein,
[0029] ; (7)
[0030] (8)
[0031] is a all-1 row vector with length ; the obtained solution is taken as the coefficient of the MTI filter.
[0032] The second aspect of the present application discloses a design device of a radar MTI filter, the device comprising:
[0033] a discretization module, configured to divide the entire response range of the MTI filter into a passband and a transition band according to the response of the system in a static environment, and discretize the passband and the transition band;
[0034] a setting module, configured to set the order N of the MTI filter, and take the minimization of the passband flatness as a cost function;
[0035] a constraint module, configured to impose a derivative constraint on the response of the MTI filter at the direct current position, and / or impose a 2-norm constraint on the response of the MTI filter in the transition band;
[0036] a solution module, configured to solve the cost function, and take the optimal solution of the cost function as the coefficient of the MTI filter.
[0037] Optionally, the device further comprises:
[0038] a frequency point set determination module, configured to determine the frequency point set of the discretized passband as , and determine the frequency point set of the discretized transition band as ; wherein is the number of frequency points of the passband, is the number of frequency points of the transition band.
[0039] The third aspect of the present application discloses another design device of a radar MTI filter, the device comprising:
[0040] a memory storing executable program codes;
[0041] a processor coupled with the memory;
[0042] The processor invokes the executable program codes stored in the memory to execute the design method of the radar MTI filter disclosed in the first aspect of the present application.
[0043] The fourth aspect of the present application discloses a computer readable storage medium, the computer readable storage medium stores computer instructions, the computer instructions are called to execute the design method of the radar MTI filter disclosed in the first aspect of the present application.
[0044] Compared with the prior art, the embodiment of the present application has the following beneficial effects:
[0045] In the embodiment of the present application, by making a multi-order derivative constraint on the filter response at 0 Doppler, the notch width of the filter to ground clutter is effectively expanded while the notch depth is ensured; at the same time, making a minimum 2 norm constraint on the filter response at other positions can control the steepness of the transition band. BRIEF DESCRIPTION OF DRAWINGS
[0046] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiment description will be briefly introduced as follows, obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained according to these drawings without creative labor for those skilled in the art.
[0047] Figure 1 is a flowchart of the design method of the radar MTI filter disclosed in the embodiment of the present application;
[0048] Figure 2 is a schematic diagram of the normalized frequency response curve of the present application;
[0049] Figure 3 is a schematic diagram of the influence of the change of the upper bound of the transition band norm constraint of the present application on the notch;
[0050] Figure 4 is a schematic diagram of the derivative constraint effect of the present application;
[0051] Figure 5 is a structural schematic diagram of the design device of the radar MTI filter disclosed in the embodiment of the present application;
[0052] Figure 6 is a structural schematic diagram of another design device of the radar MTI filter disclosed in the embodiment of the present application;
[0053] Figure 7 is a structural schematic diagram of still another design device of the radar MTI filter disclosed in the embodiment of the present application. DETAILED DESCRIPTION
[0054] In the following, the technical solutions in the embodiments of the present application will be described clearly and completely with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all the other embodiments obtained by a person of ordinary skill in the art without creative effort belong to the scope of the present application.
[0055] The terms "first", "second", and the like in the description and claims of the present application and the above drawings are used to distinguish different objects, rather than to describe a particular order. In addition, the terms "comprise" and "have" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, device, product or end including a series of steps or units is not limited to the listed steps or units, but can optionally include steps or units not listed, or can optionally include other steps or units inherent to the process, method, product or end.
[0056] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearance of the phrase in various places in the specification does not necessarily all refer to the same embodiment, nor is it necessarily mutually exclusive of other embodiments. It is explicitly and implicitly understood that the embodiments described herein can be combined with other embodiments.
[0057] Embodiment one
[0058] Please refer to Figure 1 , Figure 1 is a flowchart of a design method of a radar MTI filter disclosed in the embodiments of the present application. As shown in Figure 1 , the method can include:
[0059] Step 101, according to the response of the system in the static environment, divide the entire response range of the MTI filter into a passband and a transition band, and discretize the passband and the transition band.
[0060] Step 102, set the order N of the MTI filter, and take the minimization of the passband flatness as the cost function.
[0061] In the embodiments of the present disclosure, the minimization of the passband flatness is taken as the cost function, which can ensure that the response to high-speed targets is more stable.
[0062] Step 103, impose a derivative constraint on the response of the DC position of the MTI filter, and / or impose a 2-norm constraint on the response of the transition band of the MTI filter.
[0063] Step 104, solving the cost function, taking the optimal solution of the cost function as the coefficient of the MTI filter.
[0064] The filter designed by the design method of the radar MTI filter provided in the embodiments of the present disclosure effectively expands the notch width of the filter to the ground clutter while ensuring the notch depth by making a multi-order derivative constraint on the filter response at 0 Doppler; meanwhile, making a minimum 2 norm constraint on the filter response at other positions can control the steepness of the transition band.
[0065] Optionally, the entire response range of the MTI filter is divided into a passband and a transition band, and after discretization of the passband and the transition band, the method further comprises: determining the frequency point set of the discretized passband as , and determining the frequency point set of the discretized transition band as ; wherein, is the number of frequency points of the passband, is the number of frequency points of the transition band.
[0066] Optionally, the response of the MTI filter at the DC position is subjected to a derivative constraint, comprising: the response of the MTI filter at the DC position is subjected to one constraint or multiple constraints of 0-order to D-order derivative constraints; wherein, D is less than N-2. In this way, the notch near zero Doppler can be ensured to be smoother and the opening to be larger.
[0067] In the present disclosure, the constraint conditions do not necessarily need to be applied at the same time, and can be determined according to the filter length and specific index requirements.
[0068] Optionally, the response of the MTI filter at the DC position is subjected to a derivative constraint, and the 2 norm constraint on the response of the MTI filter in the transition band is as follows:
[0069] (1)
[0070] wherein, is the coefficient of the MTI filter, which is a column vector with a length of L; T is a vector transpose;
[0071] is a column vector with a length of L and all 1s;
[0072] ; (2)
[0073] ; (3)
[0074] ; (4)
[0075] wherein, ; is the upper limit of the transition band norm constraint;
[0076] (5)
[0077] is the D-1 order derivative of the vector e at frequency 0, where:
[0078] (6)
[0079] Thus, this optional embodiment shows the case where all the constraints are applied.
[0080] Optionally, the way to apply the derivative constraint to the response of the DC position of the MTI filter and the 2-norm constraint to the response of the transition band of the MTI filter is as follows:
[0081] (9)
[0082] where, is the coefficient of the MTI filter, which is a column vector with length L; T is the vector transpose;
[0083] is a column vector of all 1s with length L;
[0084] (2)
[0085] (3)
[0086] (4)
[0087] where, ; is the upper bound of the transition band norm constraint.
[0088] Thus, this embodiment shows the case where the 0 order and 1 order derivative constraints are applied to the response of the DC position of the MTI filter, and the 2-norm constraint is applied to the response of the transition band of the MTI filter.
[0089] In the present application, The larger the value is, the narrower the notch at the non-zero frequency position of the transition band of the filter is; the smaller the value is, the wider the notch at the non-zero frequency position of the transition band of the filter is.
[0090] Optionally, the way to solve the cost function and take the optimal solution of the cost function as the coefficient of the MTI filter is as follows:
[0091] Solve the following formula:
[0092]
[0093] where, (7)
[0094] (8)
[0095] is a all-one row vector with length ; the obtained solution is taken as the coefficient of the MTI filter.
[0096] In the present application, the optimization tool can be used to solve, that is, to obtain the optimal solution.
[0097] In a specific embodiment, the order of the MTI filter is set to 4 (i.e. L = 5);
[0098] (10) (11)
[0099] The filter coefficient obtained by using the second-order cone solution method is
[0100] (12)
[0101] The normalized frequency response curve thereof is shown in Figure 2 .
[0102] Figure 2 The frequency response of the first-order canceller, the second-order canceller and the fourth-order mean canceller is also plotted. It can be seen that the notch of the optimized filter at the ground clutter position is obviously wider than that of the first-order canceller and the mean canceller (of the same order), indicating that the suppression degree of the ground clutter is stronger than that of the two filters. At the same time, it can be seen that the transition band thereof is obviously narrower than that of the second-order canceller, indicating that the attenuation of the expected (moving) target is much smaller than that of the second-order canceller. At the same time, it can be seen from Figure 2 that the flatness of the passband of the MTI filter designed by optimization and that of the mean canceller (of the same order) are also approximate. The results demonstrate the effectiveness of the design of the present application.
[0103] To illustrate the present application, the greater the value, the narrower the notch of the filter at the non-zero frequency position of the transition band; the smaller the value, the wider the notch at the non-zero frequency position of the transition band. On the premise that the other conditions of the above specific embodiment remain unchanged, the results of δ = 0.0005, 0.005 and 0.05 are respectively investigated (see Figure 3 ), and compared with the result of δ = 0.01. It can be seen that, with the decrease of the value of δ, the notch of the filter at the transition band is getting wider and wider.
[0104] The present application uses the first derivative as an example to illustrate the effect of the derivative constraint in equation (1). The foregoing has shown that, for other conditions being the same, the smaller the δ, the wider the notch of the transition band of the filter. Therefore, the simulation under the following four conditions is continued:
[0105] Condition 1: Only set the 0th and 1st derivative constraints, and remove the 2-norm constraint;
[0106] Condition 2: Only set the 0th derivative constraint, keep the 2-norm constraint, and set δ = 0.0005;
[0107] Condition 3: Only set the 0th derivative constraint, keep the 2-norm constraint, and set δ = 0.005;
[0108] Condition 4: Only set the 0th derivative constraint, keep the 2-norm constraint, and set δ = 0.05.
[0109] Figure 4 The simulation results of the four different conditions are given. It can be seen that, as δ becomes smaller, the notch on both sides of 0 frequency of the filter becomes wider and wider. When δ is small to a certain extent (such as 0.0005), in order to maintain the global constraint of the 2-norm, the depth of the notch will be sacrificed. For example, when δ = 0.0005, the depth of the notch on both sides of 0 frequency is reduced to -80 dB. Although the notch can be widened by reducing the 2-norm constraint boundary after removing the first derivative constraint, the notch produced by the first derivative constraint is still wider at the position near 0 product. This shows that the derivative constraint has obvious effect on widening the notch width near 0 frequency.
[0110] Embodiment Two
[0111] Please refer to Figure 5 , Figure 5 is a structural schematic diagram of a design device of a radar MTI filter disclosed by an embodiment of the present application. As shown in the figure, Figure 5 the design device of the radar MTI filter can include:
[0112] A discretization module 201 is configured to divide the entire response interval of the MTI filter into a passband and a transition band according to the response of the system in a static environment, and discretize the passband and the transition band;
[0113] A setting module 202 is configured to set the order N of the MTI filter, and take the minimization of the passband flatness as a cost function;
[0114] A constraint module 203 is configured to impose a derivative constraint on the response of the DC position of the MTI filter, and / or impose a 2-norm constraint on the response of the transition band of the MTI filter;
[0115] The solving module 204 is configured to solve the cost function, and take an optimal solution of the cost function as the coefficient of the MTI filter.
[0116] It can be seen that, by the cooperation between the modules, the notch width of the filter to the ground clutter can be effectively expanded while the notch depth is ensured, and the steepness of the transition band can be controlled.
[0117] Optionally, as shown in Figure 6 , the apparatus further comprises:
[0118] The frequency point set determination module 205 is configured to determine the frequency point set of the discrete passband as , and determine the frequency point set of the discrete transition band as ; wherein, is the number of frequency points of the passband, is the number of frequency points of the transition band.
[0119] Embodiment three
[0120] Please refer to Figure 7 , Figure 7 is another structure diagram of the radar MTI filter design apparatus disclosed by the embodiments of the present application. As shown in Figure 7 , the radar MTI filter design apparatus can comprise:
[0121] The memory 301 stores executable program codes;
[0122] The processor 302 is coupled with the memory 301;
[0123] The processor 302 invokes the executable program codes stored in the memory 301 to execute the steps in the radar MTI filter design method described in the foregoing embodiments of the present application.
[0124] Embodiment four
[0125] The computer program product comprises a non-transitory computer readable storage medium storing a computer program, and the computer program is operable to cause a computer to execute the steps in the radar MTI filter design method described in the foregoing embodiments.
[0126] The apparatus embodiments described above are only illustrative, wherein the modules described as separate components can or can not be physically separated, and the components displayed as modules can or can not be physical modules, i.e., can be located in one place or distributed to multiple network modules. Part or all of the modules can be selected according to actual needs to achieve the purpose of the embodiment. Those skilled in the art can understand and implement it without creative labor.
[0127] Each embodiment in the specification is described in a progressive manner, and the same or similar parts between each embodiment can be referred to each other. Each embodiment focuses on the difference from other embodiments. In particular, for the system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the part of the method embodiment.
[0128] Through the specific description of the above embodiments, those skilled in the art can clearly understand that each embodiment can be realized by means of software and the necessary general hardware platform, and of course, it can also be realized by hardware. Based on such understanding, the above technical solutions can be embodied in the form of a software product, and the computer software product can be stored in a computer readable storage medium, including a read-only memory (ROM), a random access memory (RAM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), a one-time programmable read-only memory (OTPROM), an electrically erasable programmable read-only memory (EEPROM), a compact disc read-only memory (CD-ROM) or other optical disk storage, a magnetic disk storage, a magnetic tape storage, or any other computer readable medium that can be used to carry or store data.
[0129] It should also be noted that the terms "comprising", "comprises" or any other variation thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can also include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element preceded by "comprises a" does not exclude the existence of additional identical elements in the process, method, article, or apparatus that includes the recited element.
[0130] Finally, it should be noted that the design method and device of the radar MTI filter, and the storage medium disclosed in the embodiments of the present application are only the preferred embodiments of the present application, and are only used to illustrate the technical solutions of the present application, but not to limit them. Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that the technical solutions recorded in the foregoing embodiments can be modified, or some technical features can be replaced by equivalents. The modifications or replacements do not make the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.
Claims
1. A method of designing a radar MTI filter, characterized by, The method comprises: dividing the whole response range of the MTI filter into a passband and a transition band according to the response of the system in a static environment, and discretizing the passband and the transition band; setting the order N of the MTI filter and taking the minimization of passband flatness as a cost function; applying a derivative constraint to the response of the MTI filter at the DC position and / or applying a 2-norm constraint to the response of the MTI filter in the transition band; solving the cost function and taking the optimal solution of the cost function as the coefficients of the MTI filter.
2. The method of claim 1, wherein, After the dividing the whole response range of the MTI filter into a passband and a transition band according to the response of the system in a static environment, and discretizing the passband and the transition band, the method further comprises: The discrete frequency point set of the passband is determined as The discrete frequency point set of the transition band is determined as ; wherein, is the number of frequency points of the passband, is the number of frequency points of the transition band.
3. The method of claim 2, wherein, The applying a derivative constraint to the response of the MTI filter at the DC position comprises: applying one or more of a 0th-order to a Dth-order derivative constraint to the response of the MTI filter at the DC position; wherein D is less than N-2.
4. The method of claim 2, wherein, The applying a derivative constraint to the response of the MTI filter at the DC position and the applying a 2-norm constraint to the response of the MTI filter in the transition band are as follows: (1) wherein, are the coefficients of the MTI filter, which is a column vector of length L; T is vector transpose; is an all-one column vector of length L; ；(2) ；(3) ；(4) wherein ; is the upper bound of the transition zone norm constraint; ；(5) The vector e is constrained to the vector where: (6)。 5. The method of claim 4, wherein, The solving the cost function and taking the optimal solution of the cost function as the coefficients of the MTI filter are as follows: solving the following equation: wherein, ；(7) ；(8) is a length- 1 all-1 row vector; and is a length- 1 all-1 row vector; and The obtained solution as coefficients of the MTI filter.
6. An apparatus for designing a radar MTI filter, characterized by The apparatus comprises: a discretizing module configured to divide the whole response range of the MTI filter into a passband and a transition band according to the response of the system in a static environment, and discretize the passband and the transition band; a setting module configured to set the order N of the MTI filter and take the minimization of passband flatness as a cost function; a constraint module configured to apply a derivative constraint to the response of the MTI filter at the DC position and / or apply a 2-norm constraint to the response of the MTI filter in the transition band; a solving module configured to solve the cost function and take the optimal solution of the cost function as the coefficients of the MTI filter.
7. The apparatus of claim 6, wherein, The apparatus further comprises: The frequency point set determination module is configured to determine a frequency point set of the discrete passband as and determine a frequency point set of the discrete transition band as ; wherein, is a frequency point number of the passband, is a frequency point number of the transition band.
8. An apparatus for designing a radar MTI filter, characterized by The apparatus comprises: a memory storing executable program codes; a processor coupled to the memory; the processor invokes the executable program codes stored in the memory to execute the method for designing a radar MTI filter according to any one of claims 1-5.
9. A computer-readable storage medium, characterized in that, The computer readable storage medium stores computer instructions, which, when invoked, are used to execute the method for designing a radar MTI filter according to any one of claims 1-5.