Time domain clutter suppression performance evaluation method and device

Abstract

The invention discloses a time domain clutter suppression performance evaluation method and device, and the method comprises the steps: obtaining noise signals recorded by a reference channel and an echo channel, and calculating the first noise average energy of the reference channel and the second noise average energy of the echo channel based on the noise signals, determining a first external radiation source signal of the reference channel and a second external radiation source signal of the echo channel, calculating a first average energy of the reference channel based on the first external radiation source signal and calculating a second average energy of the echo channel based on the second external radiation source signal, calculating a first signal-to-noise ratio of the reference channel through the first noise average energy and the first average energy, calculating a second signal-to-noise ratio of the echo channel through the second noise average energy and the second average energy, and inputting the first signal-to-noise ratio and the second signal-to-noise ratio into a pre-established offset clutter-to-noise ratio calculation model to evaluate clutter suppression performance, and the problem of relatively high calculation complexity of current clutter suppression performance evaluation is solved.

Description

Technical Field

[0001] The present application relates to the technical field of signal processing, and in particular, to a method and device for evaluating the performance of time-domain clutter suppression. Background Art

[0002] In non-cooperative detection signal processing, since the structure of civilian radio and television signals is not designed for radar, the received signals have strong randomness, and the power of the continuously transmitted direct waves is very strong; ground radio and television signals mainly radiate to the ground, and multipath clutter is very strong; in addition, the gain of the antenna lobe of the transmitting antenna to airborne targets is low. The above factors result in the fact that the power of the actual target echo signal is much smaller than that of the direct wave and multipath, and the intensity difference is usually between 60 and 140 dB. Even after coherent matching, there are still high range sidelobes and Doppler sidelobes. Therefore, it is necessary to use a variety of means to perform space-time-frequency comprehensive suppression on the strong clutter in the signal receiving channel to reduce the influence of the remaining clutter after coherent processing.

[0003] Regarding the suppression of non-cooperative detection direct waves, it mainly includes the CLEAN algorithm and the iterative adaptive filtering algorithm. Such methods first estimate the relevant parameters such as the range and Doppler of the direct wave multipath based on convolution technology, and then subtract the clutter component from the time-domain received signal to separate the target signal; the iterative or block adaptive filtering algorithm obtains the adaptive filtering weight coefficients based on the Wiener filtering theory, and filters out the clutter to obtain the target signal.

[0004] According to the analysis of the existing technology, the existing research mainly focuses on the research of clutter suppression algorithms, and the suppression performance of the algorithms is evaluated by the clutter cancellation ratio. However, the calculation of this index requires the execution of clutter algorithms, and the calculation complexity is often high, which is not conducive to practical applications in engineering. Summary of the Invention

[0005] In view of the above problems, the present application provides a method and device for evaluating the performance of time-domain clutter suppression to at least solve the problems existing in the related art.

[0006] In a first aspect, an embodiment of the present application provides a method for evaluating the performance of time-domain clutter suppression, including:

[0007] Obtain a first noise signal recorded by a reference channel and a second noise signal recorded by an echo channel;

[0008] Calculate the first noise average energy of the reference channel based on the first noise signal, and calculate the second noise average energy of the echo channel based on the second noise signal;

[0009] Determine a first external radiation source signal of the reference channel and a second external radiation source signal of the echo channel;

[0010] Calculate the first average energy of the reference channel based on the first external radiation source signal, and calculate the second average energy of the echo channel based on the second external radiation source signal;

[0011] Calculate the first signal-to-noise ratio of the reference channel based on the first noise average energy and the first average energy, and calculate the second signal-to-noise ratio of the echo channel based on the second noise average energy and the second average energy;

[0012] Input the first signal-to-noise ratio and the second signal-to-noise ratio into a pre-established post-cancellation clutter-to-noise ratio calculation model to evaluate the clutter suppression performance.

[0013] In some embodiments, the inputting the first signal-to-noise ratio and the second signal-to-noise ratio into a pre-established post-cancellation clutter-to-noise ratio calculation model to evaluate the clutter suppression performance includes:

[0014] Establish a post-cancellation clutter-to-noise ratio calculation model;

[0015] After adjusting the signal acquisition time, input the corresponding first signal-to-noise ratio and second signal-to-noise ratio into the post-cancellation clutter-to-noise ratio calculation model to obtain the specific value of the post-cancellation clutter-to-noise ratio;

[0016] In the case where the specific value is less than the target threshold, determine that the current clutter suppression performance meets the detection requirements.

[0017] In some embodiments, the establishing a post-cancellation clutter-to-noise ratio calculation model includes:

[0018] Model the continuous clutter and the discrete clutter blocks available for multipath in the acquisition environment to determine the reference channel model and the echo channel model;

[0019] Based on the modulation of the reference channel model by delay and Doppler, construct a clutter sample signal model;

[0020] When the construction of the clutter sample signal model is completed, obtain the post-cancellation data based on the difference between the echo channel model and the clutter sample signal model;

[0021] Based on the limiting relationship of the solved weights in the sense of minimizing the mean square error and the post-cancellation data, deduce and replace the preset post-cancellation noise expression to obtain an initial post-cancellation clutter-to-noise ratio calculation model;

[0022] Respectively introduce the signal-to-noise ratios of the reference channel and the echo channel into the initial post-cancellation clutter-to-noise ratio calculation model for model rewriting to establish a post-cancellation clutter-to-noise ratio calculation model.

[0023] In some embodiments, the first noise average energy of the reference channel is calculated based on the first noise signal, and the second noise average energy of the echo channel is calculated based on the second noise signal, and the following calculation formula is used:

[0024]

[0025] where n ref (t i ) is the first noise signal, n tar (t i ) is the second noise signal, i = 1, 2, …, N t , is the first noise average energy, is the second noise average energy.

[0026] In some embodiments, the first average energy of the reference channel is calculated based on the first external radiation source signal, and the second average energy of the echo channel is calculated based on the second external radiation source signal, and the following calculation formula is used:

[0027]

[0028] where s ref (t i ) is the first external radiation source signal, s tar (t i ) is the second external radiation source signal, i = 1, 2, …, N t , E(|s ref (t)| 2 ) is the first average energy, E(|s tar (t)| 2 ) is the second average energy.

[0029] In some embodiments, the first signal-to-noise ratio of the reference channel is calculated based on the first noise average energy and the first average energy, and the second signal-to-noise ratio of the echo channel is calculated based on the second noise average energy and the second average energy, and the following calculation formula is used:

[0030]

[0031] where SNR ref is the first signal-to-noise ratio, SNR tar is the second signal-to-noise ratio.

[0032] In some embodiments, the expression of the cancellation post-noise ratio calculation model is:

[0033]

[0034] where SNR ref is the first signal-to-noise ratio, SNR tar is the second signal-to-noise ratio, and ∈ is a small quantity with a value less than 0.01.

[0035] In some embodiments, obtaining the first noise signal acquired by the reference channel and the second noise signal acquired by the echo channel includes:

[0036] Obtaining the first noise signal and the second noise signal acquired after the detection system is offset from the frequency point of the radiation source to be tested.

[0037] In some embodiments, determining the first external radiation source signal of the reference channel and the second external radiation source signal of the echo channel includes:

[0038] Determining the first external radiation source signal and the second external radiation source signal acquired after adjusting the detection system to the frequency point of the radiation source to be tested.

[0039] In a second aspect, an embodiment of the present application provides a device for evaluating the time-domain clutter suppression performance, including:

[0040] An acquisition module, configured to acquire the first noise signal acquired by the reference channel and the second noise signal acquired by the echo channel;

[0041] A first calculation module, configured to calculate the first noise average energy of the reference channel based on the first noise signal, and calculate the second noise average energy of the echo channel based on the second noise signal;

[0042] A determination module, configured to determine the first external radiation source signal of the reference channel and the second external radiation source signal of the echo channel;

[0043] A second calculation module, calculating the first average energy of the reference channel based on the first external radiation source signal, and calculating the second average energy of the echo channel based on the second external radiation source signal;

[0044] A third calculation module, configured to calculate the first signal-to-noise ratio of the reference channel based on the first noise average energy and the first average energy, and calculate the second signal-to-noise ratio of the echo channel based on the second noise average energy and the second average energy;

[0045] An evaluation module, configured to input the first signal-to-noise ratio and the second signal-to-noise ratio into a pre-established cancellation post-noise ratio calculation model to evaluate the clutter suppression performance.

[0046] In a third aspect, an embodiment of the present application provides an electronic device, including a memory and a processor. A program code that can run on the processor is stored on the memory. When the program code is executed by the processor, it implements the time-domain clutter suppression performance evaluation method introduced in any implementation manner of the first aspect.

[0047] In a fourth aspect, an embodiment of the present application provides a computer storage medium. The computer storage medium stores one or more programs, and the one or more programs can be executed by the electronic device introduced in the third aspect to implement the time-domain clutter suppression performance evaluation method introduced in any implementation manner of the first aspect.

[0048] A time-domain clutter suppression performance evaluation method and device provided by an embodiment of the present application obtain a first noise signal acquired by a reference channel and a second noise signal acquired by an echo channel, calculate the first noise average energy of the reference channel based on the first noise signal, and calculate the second noise average energy of the echo channel based on the second noise signal. Determine the first external radiation source signal of the reference channel and the second external radiation source signal of the echo channel, calculate the first average energy of the reference channel based on the first external radiation source signal, and calculate the second average energy of the echo channel based on the second external radiation source signal. Calculate the first signal-to-noise ratio of the reference channel based on the first noise average energy and the first average energy, and calculate the second signal-to-noise ratio of the echo channel based on the second noise average energy and the second average energy. Input the first signal-to-noise ratio and the second signal-to-noise ratio into a pre-established post-cancellation noise ratio calculation model to evaluate the clutter suppression performance. Only by calculating the average energy of the reference channel and the echo channel can the evaluation of the clutter suppression performance be completed, overcoming the problem that the current clutter suppression performance evaluation has a high computational complexity and is not conducive to engineering real-time applications.

[0049] It should be understood that the content described in this part is not intended to identify the key or important features of the embodiments of the present application, nor is it used to limit the scope of the present application. Other features of the present application will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Hereinafter, the present application will be described in more detail based on embodiments and with reference to the drawings.

[0051] Figure 1 Shows a schematic flowchart of a time-domain clutter suppression performance evaluation method proposed in an embodiment of the present application;

[0052] Figure 2 Shows a schematic diagram of an exemplary detection test application scenario based on a non-cooperative external radiation source proposed in an embodiment of the present application;

[0053] Figure 3Shows a schematic diagram of the influence of the signal-to-noise ratio of the reference channel and the echo channel on the residual clutter noise ratio in an embodiment of the present application;

[0054] Figure 4 Shows a schematic diagram of the comparison of the average energy (dBm) after digitization of the reference channel and the echo channel in an embodiment of the present application;

[0055] Figure 5 Shows a figure of the relationship between the average energy ratio of the reference and echo channels and the residual clutter noise ratio in an embodiment of the present application;

[0056] Figure 6 Shows a figure of the comparison of the average energy (dBm) after digitization of the reference channel and the echo channel in an embodiment of the present application;

[0057] Figure 7 Shows a figure of the relationship between the average energy ratio of the reference and echo channels and the residual clutter noise ratio in an embodiment of the present application;

[0058] Figure 8 Shows a block diagram of the structure of a device for evaluating the time-domain clutter suppression performance proposed in an embodiment of the present application;

[0059] Figure 9 Shows a block diagram of the structure of an electronic device for performing the time-domain clutter suppression performance evaluation method according to an embodiment of the present application;

[0060] Figure 10 Shows a computer-readable storage medium for storing or carrying the implementation of the time-domain clutter suppression performance evaluation method according to an embodiment of the present application. Detailed implementation manners

[0061] To make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below in conjunction with embodiments and drawings. The illustrative embodiments and descriptions thereof of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0062] In the research on related technologies, in non-cooperative detection, clutter suppression is a key core technology, and the clutter-to-noise ratio after cancellation affects the detection of weak targets. The basic idea of existing clutter suppression methods is to estimate the delay and Doppler of clutter through parameter estimation, then construct a corresponding clutter model, solve the weight coefficient under the meaning of the minimum energy error, and finally subtract the clutter model from the target echo channel to achieve the suppression of strong clutter and multipath. Generally speaking, the clutter suppression performance can be characterized by calculating the change of the relevant base before and after cancellation, that is, the cancellation ratio. However, a significant disadvantage of this method is that the suppression performance cannot be evaluated until the clutter suppression algorithm is completed, which is not conducive to practical applications in engineering. To address this difficulty, a time-domain clutter suppression performance evaluation method and device provided in this application start from modeling the reference channel and the target echo channel, and analyze the influence of the relative relationship between the average energies of the reference channel and the target echo channel on the clutter suppression performance from the model perspective.

[0063] The application scenarios of the time-domain clutter suppression performance evaluation method provided in the embodiments of this application are introduced as follows:

[0064] Please refer to Figure 1 , Figure 1 which is a schematic flowchart of a time-domain clutter suppression performance evaluation method provided in the embodiments of this application. In this embodiment, the time-domain clutter suppression performance evaluation method can be applied to a time-domain clutter suppression performance evaluation device 300 as shown in Figure 8 and an electronic device 200 as shown in Figure 9 . Among them, the electronic device 200 can include one or more. Exemplarily, the electronic device can include a mobile terminal, a computer, a tablet, etc., and this application does not limit it. The following elaborates in detail on the process shown in Figure 1 . The time-domain clutter suppression performance evaluation method can include S110 to S160.

[0065] S110: Obtain the first noise signal recorded by the reference channel and the second noise signal recorded by the echo channel.

[0066] In this embodiment, the first noise signal and the second noise signal are obtained after the detection system is offset from the frequency point of the radiation source to be tested.

[0067] Among them, in some embodiments, S110 may include S111 to S113.

[0068] S111: Establish a calculation model for the clutter-to-noise ratio after cancellation.

[0069] S112: After adjusting the signal recording time, input the corresponding first signal-to-noise ratio and second signal-to-noise ratio into the calculation model for the clutter-to-noise ratio after cancellation to obtain the specific value of the clutter-to-noise ratio after cancellation.

[0070] S113: When the specific value is less than the target threshold, it is determined that the current clutter suppression performance meets the detection requirements.

[0071] S120: Calculate the first noise average energy of the reference channel based on the first noise signal, and calculate the second noise average energy of the echo channel based on the second noise signal.

[0072] In the embodiment of the present application,

[0073] S130: Determine the first external radiation source signal of the reference channel and the second external radiation source signal of the echo channel.

[0074] In this embodiment, determine the first external radiation source signal and the second external radiation source signal acquired after adjusting the detection system to the frequency point of the radiation source to be tested.

[0075] S140: Calculate the first average energy of the reference channel based on the first external radiation source signal, and calculate the second average energy of the echo channel based on the second external radiation source signal.

[0076] S150: Calculate the first signal-to-noise ratio of the reference channel based on the first noise average energy and the first average energy, and calculate the second signal-to-noise ratio of the echo channel based on the second noise average energy and the second average energy.

[0077] S160: Input the first signal-to-noise ratio and the second signal-to-noise ratio into a pre-established post-cancellation clutter noise ratio calculation model to evaluate the clutter suppression performance.

[0078] Among them, inputting the first signal-to-noise ratio and the second signal-to-noise ratio into a pre-established post-cancellation clutter noise ratio calculation model to evaluate the clutter suppression performance includes:

[0079] Establish a post-cancellation clutter noise ratio calculation model;

[0080] After adjusting the signal acquisition time, input the corresponding first signal-to-noise ratio and second signal-to-noise ratio into the post-cancellation clutter noise ratio calculation model to obtain the specific value of the post-cancellation clutter noise ratio;

[0081] When the specific value is less than the target threshold, it is determined that the current clutter suppression performance meets the detection requirements.

[0082] Among them, establishing a post-cancellation clutter noise ratio calculation model includes:

[0083] Model the continuous clutter and multi-path available discrete clutter blocks in the acquisition environment to determine the reference channel model and the echo channel model;

[0084] Based on the reference channel model, after delay and Doppler modulation, construct a clutter sample signal model;

[0085] After the clutter sample signal model is constructed, the cancelled data is obtained based on the difference between the echo channel model and the clutter sample signal model;

[0086] Based on the limiting relationship of the solved weight under the meaning of the minimum mean square error and the cancelled data, the preset expression of the cancelled noise is deduced and replaced to obtain the initial calculation model of the cancelled clutter-to-noise ratio;

[0087] The signal-to-noise ratios of the reference channel and the echo channel are respectively introduced into the initial calculation model of the cancelled clutter-to-noise ratio for model rewriting to establish the calculation model of the cancelled clutter-to-noise ratio.

[0088] In this embodiment, it is assumed that the transmitting and receiving platforms are stationary, and the continuous clutter and multipath in the environment can be modeled by discrete clutter blocks. Therefore, the reference channel (Reference Channel) is modeled as follows:

[0089] s ref (t) = A ref d(t) + n ref (t), 0 ≤ t ≤ T,

[0090] where A ref is the maximum amplitude of the signal, d(t) is the envelope of the signal, and n ref (t) is the reference noise with a mean of 0 and a variance of and T is the total accumulation time.

[0091] To simplify the echo channel model, it is assumed that only the static clutter of the first N c delay units enters the target channel and there is only one target echo. Then the target echo channel (Surveillance Channel) is modeled as follows:

[0092]

[0093] where A tar is the maximum amplitude of the target echo, c i , τ i is the amplitude and time delay (delay relative to the direct signal) of the i = 1, 2,..., N c th static clutter, and T is the accumulation time; b d , τ d , f d are the amplitude, time delay, and Doppler of the target echo.

[0094] The basic idea of the time-domain cancellation algorithm is to use the reference signal s ref (t) to construct the clutter sample signal Y(t) through delay and Doppler modulation:

[0095]

[0096] After the construction of the sample signal is completed, subtract the constructed sample signal Y(t) from the target channel signal s tar (t) to obtain the data after cancellation as follows:

[0097]

[0098] where,

[0099]

[0100] Generally, the weights ω i , i = 0, 1, …, N c satisfy the following relationship

[0101]

[0102] After further calculation, it can be obtained that:

[0103]

[0104] where, is a small quantity, and the influence of the cross term on the energy of the echo channel can be ignored, that is, the energy of the target echo channel can be approximated as follows:

[0105]

[0106] Note a commonly used ability evaluation index for clutter suppression: the clutter-to-noise ratio after cancellation, which is defined as follows:

[0107]

[0108] where, when ∈ and the target echo b 0 are small enough, the magnitude of the clutter-to-noise ratio after cancellation mainly depends on the energy of the noise after cancellation . Recall the expression of the noise after cancellation

[0109]

[0110] Under the assumption that the noise in n ref and the noise in n tar are independent of each other, the first calculation formula is obtained through derivation as follows:

[0111]

[0112] and the second calculation formula:

[0113] ​

[0114]

[0115] The stationarity and mutual independence of the noise signal are used here. That is and Note that the weight ω i has the following expression:

[0116]

[0117] Substituting the above results into the first calculation formula, we can get:

[0118]

[0119] Note that

[0120]

[0121] According to the above expression, it can be known that the expression of the clutter-to-noise ratio after cancellation is

[0122]

[0123] The energy signal-to-noise ratios of the reference channel and the echo channel are introduced as follows

[0124]

[0125] Therefore, the expression of the clutter-to-noise ratio after cancellation is rewritten as the third calculation formula:

[0126]

[0127] Among them, the third calculation formula establishes a quantitative relationship between the clutter-to-noise ratio after cancellation and the energy signal-to-noise ratios of the reference channel and the echo channel. In engineering practical applications, the signal-to-noise ratios of the energy of the reference channel and the echo channel are easy to calculate. In this way, the current signal quality can be conveniently evaluated and the clutter suppression performance of the algorithm can be evaluated by using the third calculation formula.

[0128] In the above embodiment, from the second calculation formula and the appendix Figure 3 it can be known that when the average energy of the target echo channel is equal to the average energy of the reference channel, the clutter-to-noise ratio after cancellation is 3 dB (that is, the relevant base after cancellation is still 3 dB higher than the environmental noise base); when the average energy of the target echo channel is 10 dB lower than the average energy of the reference channel, the clutter-to-noise ratio after cancellation is about 0.5 dB; when the average energy of the target echo channel is 10 dB higher than the average energy of the reference channel, the clutter-to-noise ratio after cancellation is about 10.4 dB. Therefore, assuming that the sampling rate of the system is, according to the quantitative evaluation formula of the clutter-to-noise ratio after cancellation.

[0129] The following are the specific steps of the time-domain clutter suppression performance evaluation method:

[0130] S1: The noise signals in the environment are respectively acquired by the reference channel and the echo channel.

[0131] In this embodiment, first, the detection system is offset from the frequency point of the radiation source to be tested, and the noise signals of the reference channel and the echo channel are acquired for T seconds. Then, the number of acquisition points of the reference signal and the echo signal is That is, n ref (t i ), n tar (t i ), i = 1, 2,..., N t .

[0132] S2: According to the reference channel data n ref (t i ) and the echo channel data n tar (t i ), i = 1, 2,..., N t , calculate the average noise energy of the reference channel and the target echo channel respectively.

[0133]

[0134] S3: The external radiation source signals in the environment are respectively acquired by the reference channel and the echo channel.

[0135] In this embodiment, first, the detection system is adjusted to the frequency point of the radiation source to be tested, and the signals of the reference channel and the echo channel are acquired for T seconds. Then, the number of acquisition points of the reference signal and the echo signal is That is, s ref (t i ), s tar (t i ), i = 1, 2,..., N t .

[0136] S4: Calculate the average energy of the reference channel and the target echo channel respectively according to the sampling data.

[0137]

[0138] S5: Calculate the signal-to-noise ratios of the reference channel and the echo channel respectively according to the average energies of the radiation source signal and the noise signal.

[0139]

[0140] S6: According to the third calculation formula described quantitatively in the above embodiment, calculate the specific value of the clutter-to-noise ratio after cancellation as:

[0141]

[0142] The above steps can adjust the time of each signal acquisition according to the actual application, and are used to evaluate the clutter suppression performance in real time dynamically. The value of the clutter-to-noise ratio ECA after cancellation is used as the evaluation criterion for the cancellation performance. According to the actual engineering application, when the clutter-to-noise ratio after cancellation is less than 5 dB, it is considered that the current clutter suppression result can be used for subsequent coherent processing and weak target detection.

[0143] In this application, aiming at the problem that it is difficult to evaluate the clutter suppression performance for dynamic signals in the environment, the present invention gives a fast quantitative evaluation method through theoretical derivation. This invention effectively reduces the computational complexity required for performance evaluation and brings convenience to the actual engineering application. In order to fully verify the effectiveness of the invention, measured data is acquired in an actual test scenario, and the influence of the signal-to-noise ratios of the average energy of the reference channel and the average energy of the target echo channel on the clutter suppression performance is verified, thereby verifying the correctness and effectiveness of the third calculation formula. For details, please refer to the implementation examples.

[0144] The specific implementation manner is as follows:

[0145] To verify the effectiveness of the fast evaluation method proposed by the present invention, a certain civilian radio is used as a non-cooperative illumination source, and the test scenario is arranged in the manner as Figure 2 . The effectiveness of this application is verified by acquiring test data of different batches multiple times. This detection system consists of a detection array and a reference antenna. Among them, the beam of the target detection antenna points to the detection airspace for acquiring target echo signals; the beam of the reference antenna points to the non-cooperative civilian illumination source for acquiring direct reference signals. During the test process, ensure that the pointing of the reference antenna remains unchanged, and simulate the changes in the energies of the reference channel and the target echo channel by adjusting the beam pointing of the detection array antenna, and acquire echo data multiple times to verify the fast evaluation formula.

[0146] According to the actual situation, two sets of typical data are acquired. The average energy of the echo channel of the data acquired in the first test is roughly equivalent to the energy of the reference channel. The specific values are as Figure 4 shown. The comparison between the theoretical value and the actual calculated value of the third calculation formula for the fast evaluation of the clutter-to-noise ratio after cancellation is as Figure 5 and shown in Table 1 below.

[0147] Table 1 Verification of the fast evaluation formula and the actual cancellation ratio (Test 1)

[0148]

[0149] It can be seen from the comparison that the difference between the theoretical value and the actual calculated value does not exceed 1 dB; for the data acquired in the second test, the average energy of the echo channel is much smaller than the average energy of the reference channel (the average energy of the echo channel is more than 10 dB smaller than the energy of the reference channel). The specific values are as Figure 6As shown, the comparison between the theoretical value calculated from the third calculation formula and the actual calculated value is as follows Figure 7 and as shown in Table 2 below:

[0150] Table 2 Verification of the Fast Evaluation Formula and the Actual Cancellation Ratio (Test 2)

[0151]

[0152] From the comparison, it can be seen that the difference between the theoretical value and the actual calculated value does not exceed 1 dB. The above comparison results fully verify the effectiveness of the fast evaluation formula.

[0153] In summary, when the average energy of the reference channel is weaker than that of the target echo channel, the clutter-to-noise ratio after cancellation is relatively high; when the average energy of the reference channel is much greater than the energy of the echo channel, the remaining clutter after cancellation is relatively small. Therefore, the fast evaluation method of the present invention can be applied to engineering practice.

[0154] Please refer to Figure 8 , Figure 8 which is the structural block diagram of a device for evaluating the performance of time-domain clutter suppression provided by this application. The device 300 for evaluating the performance of time-domain clutter suppression includes: an acquisition module 310, a first calculation module 320, a determination module 330, a second calculation module 340, a third calculation module 350, and an evaluation module 360, where:[[]]

[0155] The acquisition module 310 is configured to acquire a first noise signal acquired by a reference channel and a second noise signal acquired by an echo channel.

[0156] The first calculation module 320 is configured to calculate the first noise average energy of the reference channel based on the first noise signal, and calculate the second noise average energy of the echo channel based on the second noise signal.

[0157] The determination module 330 is configured to determine a first external radiation source signal of the reference channel and a second external radiation source signal of the echo channel.

[0158] The second calculation module 340 calculates the first average energy of the reference channel based on the first external radiation source signal, and calculates the second average energy of the echo channel based on the second external radiation source signal.

[0159] The third calculation module 350 is configured to calculate the first signal-to-noise ratio of the reference channel based on the first noise average energy and the first average energy, and calculate the second signal-to-noise ratio of the echo channel based on the second noise average energy and the second average energy.

[0160] The evaluation module 360 is configured to input the first signal-to-noise ratio and the second signal-to-noise ratio into a pre-established calculation model of the clutter-to-noise ratio after cancellation to evaluate the clutter suppression performance.

[0161] The device embodiments in this application may further include other modules, which specifically correspond to the content in the above method section.

[0162] It should be noted that the device embodiments in this application correspond to the foregoing method embodiments. The specific principles in the device embodiments can be referred to the content in the foregoing method embodiments, and will not be elaborated here.

[0163] In several embodiments provided in this embodiment, the coupling between modules can be electrical, mechanical or other forms of coupling.

[0164] In addition, in each embodiment of the present invention, the various functional modules can be integrated in a processing module, or each module can exist physically alone, or two or more modules can be integrated in one module. The above integrated modules can be implemented in the form of hardware or in the form of software functional modules.

[0165] Please refer to Figure 9 , Figure 9 , which is a structural block diagram of an electronic device 200 that can execute the above-mentioned time-domain clutter suppression performance evaluation method provided by the embodiment of the present application. The electronic device 200 can be a smart phone, a tablet computer, a computer, a portable computer or other devices.

[0166] The electronic device 200 further includes a processor 202 and a memory 204. Among them, the memory 204 stores a program that can execute the content in the foregoing embodiments, and the processor 202 can execute the program stored in the memory 204.

[0167] Among them, the processor 202 may include one or more cores for processing data and a message matrix unit. The processor 202 connects various parts within the entire electronic device 200 through various interfaces and circuits, and executes various functions of the electronic device 200 and processes data by running or executing instructions, programs, code sets, or instruction sets stored in the memory 204, and by calling the data stored in the memory 204. Optionally, the processor 202 may be implemented in at least one hardware form of digital signal processing (DSP), field-programmable gate array (FPGA), or programmable logic array (PLA). The processor 202 may integrate a combination of one or several of a central processing unit (CPU), a graphics processing unit (GPU), and a modem decoder. Among them, the CPU mainly processes the operating system, user interface, application programs, etc.; the GPU is responsible for rendering and drawing the displayed content; the modem is used to process wireless communications. It can be understood that the above-mentioned modem decoder may not be integrated into the processor and may be implemented separately through a communication chip.

[0168] The memory 204 may include a random access memory (RAM), or may also include a read-only memory. The memory 204 can be used to store instructions, programs, code, code sets, or instruction sets. The memory 204 may include a program storage area and a data storage area. The program storage area may store instructions for implementing the operating system, instructions for implementing at least one function (such as instructions for a user to obtain a random number), instructions for implementing the following various method embodiments, etc. The data storage area may also store data created during the use of the terminal (such as random numbers), etc.

[0169] The electronic device 200 may further include a network module and a screen. The network module is used to receive and send electromagnetic waves, realize the mutual conversion between electromagnetic waves and electrical signals, so as to communicate with a communication network or other devices, such as communicating with an audio playback device. The network module may include various existing circuit elements for performing these functions, such as antennas, radio frequency transceivers, digital signal processors, encryption / decryption chips, subscriber identity module (SIM) cards, memories, and so on. The network module can communicate with various networks such as the Internet, enterprise intranets, wireless networks or communicate with other devices through a wireless network. The above-mentioned wireless network may include a cellular phone network, a wireless local area network or a metropolitan area network. The screen can display interface content and perform data interaction.

[0170] Please refer to Figure 10 , Figure 10 shows a structural block diagram of a computer-readable storage medium provided by an embodiment of the present application. Program code 410 is stored in the computer-readable storage medium 400, and the program code 410 can be called by a processor to execute the method described in the above method embodiment.

[0171] The computer-readable storage medium 400 may be an electronic memory such as a flash memory, EEPROM (electrically erasable programmable read-only memory), EPROM, hard disk or ROM. Optionally, the computer-readable storage medium includes a non-transitory computer-readable storage medium. The computer-readable storage medium 400 has a storage space for the program code 410 that executes any method step in the above method. These program codes 410 can be read from or written into one or more computer program products. The program code 410 may be compressed in an appropriate form, for example.

[0172] The embodiment of the present application also provides a computer program product or a computer program. The computer program product or the computer program includes computer instructions, and the computer instructions are stored in a computer-readable storage medium. The processor of the computer device reads the computer instructions from the computer-readable storage medium, and the processor executes the computer instructions, so that the computer device executes the time-domain clutter suppression performance evaluation method described in the above various optional implementation manners.

[0173] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the various embodiments of the present application.

Claims

1. A method for evaluating clutter suppression performance in the time domain, characterized in that: The method comprises: Acquire a first noise signal recorded by a reference channel and a second noise signal recorded by an echo channel; Calculating a first noise average energy of the reference channel based on the first noise signal, and calculating a second noise average energy of the echo channel based on the second noise signal; Determining a first external radiation source signal of the reference channel and a second external radiation source signal of the echo channel; Calculating a first average energy of the reference channel based on the first external radiation source signal, and calculating a second average energy of the echo channel based on the second external radiation source signal; Calculate a first signal-to-noise ratio of the reference channel based on the first noise average energy and the first average energy, and calculate a second signal-to-noise ratio of the echo channel based on the second noise average energy and the second average energy; The first signal-to-noise ratio and the second signal-to-noise ratio are input into a pre-established post-cancellation clutter-to-noise ratio calculation model to evaluate the clutter suppression performance.

2. The time domain clutter suppression performance evaluation method according to claim 1, characterized in that: The step of inputting the first signal-to-noise ratio and the second signal-to-noise ratio into a pre-established post-cancellation noise-to-clutter ratio calculation model to evaluate the clutter suppression performance includes: Establish a calculation model for noise-cancelation ratio after cancellation; After adjusting the signal recording time, the corresponding first signal-to-noise ratio and second signal-to-noise ratio are input into the post-cancellation noise-to-noise ratio calculation model to obtain a specific value of the post-cancellation noise-to-noise ratio; When the specific value is less than the target threshold, it is determined that the current clutter suppression performance meets the detection requirement.

3. The time domain clutter suppression performance evaluation method according to claim 2, characterized in that: The method of establishing a calculation model for the noise-cancelation ratio after cancellation includes: The continuous clutter and multipath in the recording environment can be modeled using discrete clutter blocks to determine the reference channel model and the echo channel model; Constructing a clutter sample signal model based on the reference channel model after delay and Doppler modulation; After the clutter sample signal model is constructed, canceled data is obtained based on the difference between the echo channel model and the clutter sample signal model; Based on the limiting relationship of the weights to be solved in the sense of minimum mean square error and the data after cancellation, a preset noise expression after cancellation is derived and replaced to obtain an initial calculation model of the noise-to-cancelation ratio after cancellation; The signal-to-noise ratios of the reference channel and the echo channel are respectively introduced into the initial calculation model of the post-cancellation noise-to-cancelation ratio to rewrite the model, so as to establish a calculation model of the post-cancellation noise-to-cancelation ratio.

4. The time domain clutter suppression performance evaluation method according to claim 1, characterized in that: The first noise average energy of the reference channel is calculated based on the first noise signal, and the second noise average energy of the echo channel is calculated based on the second noise signal, using the following calculation formula: Among them, n ref (t i ) is the first noise signal, n tar (t i ) is the second noise signal, i=1,2,…,N t , is the first noise average energy, is the second noise average energy.

5. The time domain clutter suppression performance evaluation method according to claim 4, characterized in that: The first average energy of the reference channel is calculated based on the first external radiation source signal, and the second average energy of the echo channel is calculated based on the second external radiation source signal, using the following calculation formula: Among them, s ref (t i ) is the first external radiation source signal, s tar (t i ) is the second external radiation source signal, i=1,2,…,N t ,E(|s ref (t)| 2 ) is the first average energy, E(|s tar (t)| 2 ) is the second average energy.

6. The time domain clutter suppression performance evaluation method according to claim 5, characterized in that: The first signal-to-noise ratio of the reference channel is calculated based on the first noise average energy and the first average energy, and the second signal-to-noise ratio of the echo channel is calculated based on the second noise average energy and the second average energy, using the following calculation formula: Among them, SNR ref is the first signal-to-noise ratio, SNR tar is the second signal-to-noise ratio.

7. The time domain clutter suppression performance evaluation method according to claim 1, characterized in that: The expression of the noise-to-noise ratio calculation model after cancellation is: Among them, SNR ref is the first signal-to-noise ratio, SNR tar is the second signal-to-noise ratio, ∈ is a small quantity, and its value is less than 0.

01.

8. The time domain clutter suppression performance evaluation method according to claim 1, characterized in that: The step of obtaining a first noise signal calculated by a reference channel and a second noise signal calculated by an echo channel includes: The first noise signal and the second noise signal recorded after the detection system and the radiation source to be tested are deviated in frequency are obtained.

9. The time domain clutter suppression performance evaluation method according to claim 8, characterized in that: The determining of the first external radiation source signal of the reference channel and the second external radiation source signal of the echo channel comprises: Determine the first external radiation source signal and the second external radiation source signal recorded after the detection system is adjusted to the frequency point of the radiation source to be tested.

10. A time domain clutter suppression performance evaluation device, characterized in that: The device comprises: An acquisition module, used for acquiring a first noise signal recorded by a reference channel and a second noise signal recorded by an echo channel; A first calculation module, configured to calculate a first noise average energy of the reference channel based on the first noise signal, and calculate a second noise average energy of the echo channel based on the second noise signal; A determination module, used to determine a first external radiation source signal of the reference channel and a second external radiation source signal of the echo channel; a second calculation module, calculating a first average energy of the reference channel based on the first external radiation source signal, and calculating a second average energy of the echo channel based on the second external radiation source signal; A third calculation module, configured to calculate a first signal-to-noise ratio of the reference channel based on the first noise average energy and the first average energy, and to calculate a second signal-to-noise ratio of the echo channel based on the second noise average energy and the second average energy; An evaluation module is used to input the first signal-to-noise ratio and the second signal-to-noise ratio into a pre-established post-cancellation noise-to-noise ratio calculation model to evaluate the clutter suppression performance.

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