Method for target echo detection of multi-carrier underwater acoustic communication and sensing integrated system

Abstract

The application relates to an echo detection method, device, equipment, storage medium and program product. The method comprises the following steps: acquiring a to-be-detected signal in a preset time window. Since the to-be-detected signal comprises a plurality of signals corresponding to a plurality of signal transmission paths, the Doppler frequency shift type comprises consistent frequency shifts of signal components or inconsistent frequency shifts of signal components, and therefore, the Doppler frequency shift type of the to-be-detected signal needs to be determined according to the to-be-detected signal, and the to-be-detected signal is subjected to echo detection according to the Doppler frequency shift type, so as to determine whether the to-be-detected signal comprises an echo signal. The method can improve the accuracy of echo detection.

Description

Technical Field

[0001] This application relates to the field of integrated underwater acoustic communication and sensing technology, and in particular to a target echo detection method for a multi-carrier integrated underwater acoustic communication and sensing system. Background Technology

[0002] With the development of communication technology, integrated communication and sensing technology has been widely used. For example, implementing integrated communication and sensing technology underwater can accomplish tasks such as target detection, tracking, identification and information sharing, and echo detection is a common sensing method.

[0003] Traditional echo detection methods typically use matched filters to filter the received signal and select the signal corresponding to the strongest signal transmission path for echo detection.

[0004] However, the above-mentioned echo detection method has the problem of inaccurate detection. Summary of the Invention

[0005] Therefore, it is necessary to provide an echo detection method, apparatus, equipment, storage medium, and program product that can improve the accuracy of echo detection in response to the above-mentioned technical problems.

[0006] Firstly, this application provides an echo detection method, comprising:

[0007] Acquire the signal to be detected within a preset time window. The signal to be detected includes multiple signals corresponding to multiple signal transmission paths.

[0008] Based on the signal to be detected, determine the Doppler frequency shift type of the signal to be detected. The Doppler frequency shift type includes whether the frequency shift of each signal component is the same or the frequency shift of each signal component is inconsistent.

[0009] Based on the Doppler frequency shift type, echo detection is performed on the signal to be detected to determine whether the signal to be detected includes an echo signal.

[0010] In one embodiment, echo detection of the signal to be detected is performed based on the Doppler frequency shift type, including:

[0011] When the Doppler frequency shift type is that the frequency shifts of each signal component are the same, the first Doppler frequency shift value corresponding to each signal component is determined according to the signal to be detected, and the first Doppler frequency shift value corresponding to each signal component is the same;

[0012] Echo detection is performed on the signal to be detected based on the first Doppler frequency shift value corresponding to each signal component.

[0013] In one embodiment, echo detection of the signal to be detected is performed based on the signal to be detected and the first Doppler frequency shift values ​​corresponding to each signal component, including:

[0014] Based on the signal to be detected and each first Doppler frequency shift value, the first probability density and the second probability density corresponding to the signal to be detected are determined. The first probability density is used to characterize the probability distribution of the presence of echo signals in the signal to be detected, and the second probability density is used to characterize the probability distribution of the absence of echo signals in the signal to be detected.

[0015] Echo detection is performed on the signal to be detected based on the ratio of the probability density of the first probability density to the probability density of the second probability density.

[0016] In one embodiment, echo detection of the signal to be detected is performed based on the probability density ratio of the first probability density and the second probability density, including:

[0017] When the probability density ratio is greater than or equal to the first ratio threshold, it is determined that the signal to be detected has an echo signal;

[0018] If the probability density ratio is less than the first ratio threshold, it is determined that the signal to be detected does not have an echo signal.

[0019] In one embodiment, determining the first Doppler frequency shift value corresponding to each signal component based on the signal to be detected includes:

[0020] Based on different candidate Doppler frequency shift values, multiple predicted signals corresponding to each candidate Doppler frequency shift value are determined;

[0021] Obtain the signal difference between the signal to be detected and each predicted signal;

[0022] The candidate Doppler frequency shift value corresponding to the predicted signal with the smallest signal difference is taken as the first Doppler frequency shift value.

[0023] In one embodiment, echo detection of the signal to be detected is performed based on the Doppler frequency shift type, including:

[0024] When the Doppler frequency shift type is that the frequency shifts of each signal component are inconsistent, at least one effective path is determined from each signal transmission path based on each signal component.

[0025] Based on the multiple valid signals corresponding to each valid path, echo detection is performed on the signal to be detected.

[0026] In one embodiment, echo detection is performed on the signal to be detected based on multiple valid signals corresponding to each valid path, including:

[0027] Based on each valid signal, the second Doppler frequency shift value corresponding to each valid signal is obtained, and the second Doppler frequency shift value corresponding to each valid signal is different;

[0028] Based on each effective signal and each second Doppler frequency shift value, the distance data corresponding to each effective signal is determined. The distance data includes a first amplitude value, which is used to characterize the maximum radiation intensity of the effective signal.

[0029] Based on the distance data, echo detection is performed on the signal to be detected.

[0030] In one embodiment, echo detection is performed on the signal to be detected based on various distance data, including:

[0031] Add the first amplitude values ​​corresponding to each valid signal to obtain the amplitude sum value;

[0032] If the amplitude value and the sum value are greater than or equal to the preset sum value threshold, it is determined that the signal to be detected has an echo signal;

[0033] If the amplitude value and the sum value are less than the preset sum value threshold, it is determined that there is no echo signal in the signal to be detected.

[0034] In one embodiment, the distance data further includes amplitude delay, and echo detection is performed on the signal to be detected based on the distance data, including:

[0035] Based on the amplitude value, amplitude delay and second Doppler frequency shift value corresponding to each valid signal, determine the first energy value corresponding to each valid signal, and obtain the energy value and value of each first energy value;

[0036] Based on the signal to be detected, determine the second energy value corresponding to the signal to be detected;

[0037] If the energy ratio of the sum of the energy values ​​to the second energy value is greater than or equal to the second ratio threshold, then it is determined that the signal to be detected has an echo signal.

[0038] If the energy ratio of the sum of the energy values ​​to the second energy value is less than the second ratio threshold, then it is determined that the signal to be detected does not have an echo signal.

[0039] In one embodiment, determining at least one valid path from each signal transmission path based on each signal component includes:

[0040] Based on each signal component, determine the second amplitude value corresponding to each signal component;

[0041] The signal transmission path corresponding to the signal whose second amplitude value is greater than the preset amplitude value threshold is taken as the valid path.

[0042] Secondly, this application also provides an echo detection device, comprising:

[0043] The acquisition module is used to acquire the signal to be detected within a preset time window. The signal to be detected includes multiple signals corresponding to multiple signal transmission paths.

[0044] The determination module is used to determine the Doppler frequency shift type of the signal to be detected based on the signal to be detected. The Doppler frequency shift type includes whether the frequency shifts of each signal component are consistent or the frequency shifts of each signal component are inconsistent.

[0045] The echo detection module is used to perform echo detection on the signal to be detected based on the Doppler frequency shift type, so as to determine whether the signal to be detected includes an echo signal.

[0046] Thirdly, embodiments of this application provide a computer device, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps of the method described in the first aspect above.

[0047] Fourthly, embodiments of this application provide a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the steps of the method described in the first aspect above.

[0048] Fifthly, this application also provides a computer program product. The computer program product includes a computer program that, when executed by a processor, implements the steps of the method described in the first aspect above.

[0049] The aforementioned echo detection method, apparatus, device, storage medium, and program product acquire the signal to be detected within a preset time window. Since the signal to be detected includes multiple signals corresponding to multiple signal transmission paths, and the Doppler frequency shift type includes whether the frequency shifts of each signal component are consistent or inconsistent, it is necessary to determine the Doppler frequency shift type of the signal to be detected based on the signal to be detected, and then perform echo detection on the signal to be detected according to the Doppler frequency shift type to determine whether the signal to be detected includes an echo signal. Traditional echo detection methods only select the signal from the strongest signal transmission path for echo detection, without considering the diversity of signal transmission paths in actual application scenarios, which poses a risk of missed detections. Furthermore, they do not consider the impact of Doppler interference on the signal during detection, resulting in low accuracy. In contrast, the echo detection method, apparatus, device, storage medium, and program product provided in this application perform echo detection on signals to be detected that include multiple signal transmission paths based on different Doppler frequency shift types, thus improving the accuracy of echo detection. Attached Figure Description

[0050] To more clearly illustrate the technical solutions in the embodiments or related technologies of this application, the accompanying drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0051] Figure 1 This is a diagram illustrating the application environment of the echo detection method in one embodiment;

[0052] Figure 2 This is a flowchart illustrating an echo detection method in one embodiment;

[0053] Figure 3 In another embodiment, the distance profile between the echo detection device and the target corresponding to the signals to be detected at different Doppler frequency shifts is shown.

[0054] Figure 4 This is a schematic diagram of the channel response under different Doppler frequency shift types in another embodiment;

[0055] Figure 5 This is a flowchart illustrating step 203 in another embodiment;

[0056] Figure 6 The graph shows the detection effect of the echo detection method provided in this application and the detection effect of the traditional echo detection method when the Doppler frequency shift type is the same for all signal components in another embodiment.

[0057] Figure 7 The graph shows the detection performance of the echo detection method provided in this application under different false alarm probabilities in another embodiment, and the detection performance of the traditional echo detection method.

[0058] Figure 8 This is a flowchart illustrating step 203 in another embodiment;

[0059] Figure 9 This is a flowchart illustrating step 802 in another embodiment;

[0060] Figure 10 This is a diagram illustrating the difference between using energy values ​​and using amplitude and value for echo detection when the Doppler frequency shift type is inconsistent among the signal components, as described in another embodiment.

[0061] Figure 11 This is a detection probability diagram of two different implementations with the same number of valid signals in another embodiment;

[0062] Figure 12 This is a detection probability diagram for two different implementations in another embodiment where the number of subcarriers is the same;

[0063] Figure 13 This is a detection probability diagram for two different implementations in another embodiment where the subcarrier spacing is the same;

[0064] Figure 14This is a structural block diagram of an echo detection device in one embodiment;

[0065] Figure 15 This is an internal structural diagram of a computer device in one embodiment. Detailed Implementation

[0066] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0067] With the increasing efforts in marine resource development and marine scientific research, the demand for marine information technology is also constantly rising, especially in underwater monitoring and data acquisition. The underwater Internet of Things (IoT), comprised of various platforms and sensors, will play a crucial role in these areas. The rapid development of electronic information systems places higher demands on the intelligence and integration of payload equipment mounted on underwater platforms to adapt to their mission execution capabilities in complex marine environments. Underwater acoustic communication and sensing technologies are key technologies supporting underwater platforms in achieving target perception, tracking, identification, and information sharing. However, the current independent research and use of communication and sensing sonar equipment not only leads to serious mutual interference but also reduces the utilization rate of underwater resources and operational efficiency. To address this issue, it is urgent to explore the organic integration of communication and sensing functions to improve the overall effectiveness of underwater information systems.

[0068] Integrated sensing and communication (ISAC) technology is a promising means of information transmission and acquisition in future marine information networks. The main idea of ​​underwater acoustic ISAC is based on sharing hardware and software resources at both the dry and wet ends, sharing transmitted waveforms, and designing resource allocation and signal processing methods to achieve simultaneous communication and sensing functions at the same frequency. Multicarrier technology is a commonly used, efficient, and reliable communication technology. Orthogonal frequency division multiplexing (OFDM), as a special type of multicarrier technology, has been applied in many communication standards and radar systems due to its efficient system implementation, high spectral efficiency, and robustness against inter-symbol interference. It is also one of the important technologies widely used in ISAC systems. Unlike traditional OFDM communication and radar systems, OFDM-based underwater acoustic ISAC systems need to simultaneously focus on information transmission and target sensing performance. Although existing communication processing algorithms can be directly or slightly modified for communication information recovery in ISAC systems, target echo detection, affected by random information and complex acoustic channels, is a key problem that multicarrier underwater acoustic ISAC systems need to solve.

[0069] Echo signal detection is the foundation and prerequisite for target parameter estimation. It can be accomplished by a sensing receiver mounted on an underwater ISAC platform. By detecting the echo signal, we can determine whether there is an echo signal in the received signal, thereby determining whether the target exists. Subsequently, we can effectively estimate the target's speed, distance, azimuth, and other parameters based on the echo signal, thus completing the target detection.

[0070] Most existing research on multi-carrier ISAC echo detection methods focuses on terrestrial wireless channels. However, due to significant differences in transmission channel models between terrestrial and underwater environments, and the complex time-frequency-space-varying characteristics and stronger background noise interference of underwater acoustic channels, terrestrial technologies cannot be directly applied to underwater acoustic channel environments and are not even of reference value. Traditional echo detection methods based on matched filtering only utilize the direct path information of the echo signal for detection. Underwater acoustic channels are typical multipath channels and usually exhibit significant sparsity. Utilizing only a single path will inevitably increase the probability of missed detections and result in low information utilization, thus limiting detection performance.

[0071] Therefore, the above-mentioned echo detection method has the problem of inaccurate detection.

[0072] In view of this, embodiments of this application provide an echo detection method, apparatus, device, storage medium, and program product. The method acquires a signal to be detected within a preset time window. Since the signal to be detected includes multiple signals corresponding to multiple signal transmission paths, and the Doppler frequency shift type includes whether the frequency shifts of each signal component are consistent or inconsistent, it is necessary to determine the Doppler frequency shift type of the signal to be detected based on the signal to be detected, and then perform echo detection on the signal to be detected based on the Doppler frequency shift type to determine whether the signal to be detected includes an echo signal. Traditional echo detection methods only select the signal from the strongest signal transmission path for echo detection, without considering the diversity of signal transmission paths in actual application scenarios, leading to the risk of missed detections. Furthermore, they do not consider the impact of Doppler interference on the signal during detection, resulting in low accuracy. However, the target echo detection method for a multi-carrier underwater acoustic communication and sensing integrated system provided in this application performs echo detection on signals to be detected that include multiple signal transmission paths based on different Doppler frequency shift types, thus improving the accuracy of echo detection.

[0073] The echo detection method provided in this application embodiment can be applied to, for example... Figure 1 The application environment shown is illustrated. The echo detection device can be any device equipped with an integrated communication and sensing system, capable of emitting signals and performing echo detection on received signals. In one possible implementation, the echo detection device may include an underwater acoustic ISAC system.

[0074] In one exemplary embodiment, such as Figure 2 As shown, an echo detection method is provided, which is applied to... Figure 1 Taking the echo detection equipment in the example, the explanation includes the following steps 201 to 203. Wherein:

[0075] Step 201: Acquire the signal to be detected within a preset time window.

[0076] When the echo detection device performs a target detection task, it emits a signal and receives the signal within a preset window. By processing the signal, the signal to be detected can be obtained. The signal to be detected includes multiple signals corresponding to multiple signal transmission paths.

[0077] The preset time window is a time period. In this embodiment, after the echo detection device emits an integrated signal for underwater acoustic communication and sensing, it will receive the signal to be detected within the preset time window. In one possible implementation, in actual application scenarios, there may be situations where the target is too far away from the echo detection device. In this case, the signal to be detected that has an echo signal may not be received within the preset time window. To avoid missed detections and improve detection efficiency, a sliding time window method can be used. For example, the preset time window is T. w Then every time T s Slide the time window to the current moment; for example, the preset time window range is 0 to T. w When time T passed s Then, sliding the preset time window will change the time range of the preset time window to T again. s ~T w +T s .

[0078] In one possible implementation, the signal to be detected acquired by the echo detection device within a preset time window can be represented by superimposing environmental noise onto the integrated signal emitted by the echo detection device after reflection from the target. The signal emitted by the echo detection device can have a duration of T and include N. c For an OFDM symbol of k subcarriers, the frequency f of the kth subcarrier can be set. k The expression is:

[0079] f k =f l +kΔf,k=0,…,N c -1(1)

[0080] Among them, f l Given the carrier frequency and Δf as the subcarrier spacing, the bandwidth B = N. c If Δf is given, then the complex baseband signal corresponding to the m-th symbol block can be represented by the following formula.

[0081]

[0082] Where n∈[0,N] c -1] represents the discrete-time index variable, d m [k] = [d[0],d[1],…,d[N] c -1]] T This represents the phase-modulated symbol transmitted in the m-th symbol block, which includes data and pilot symbols, i.e., s m (n) is d m [k] is the result obtained after the inverse Fourier transform.

[0083] After up-conversion, the baseband signal is converted into a passband transmission signal, which can be represented by the following formula.

[0084]

[0085] Where t∈[0,T′], T′ is the time interval between the transmission of multi-carrier pulses by the echo detection device, T′=T+T g T g For zero-crossing protection time, g(t) represents the rectangular window function.

[0086] In this embodiment of the application, after the echo detection device emits a signal, if there is a target in the underwater measurement area, the signal to be detected obtained by the echo detection device will contain the target echo signal. However, the relative position between the target and the echo detection device is not necessarily constant. When there is relative motion between the target and the echo detection device, the frequency of the received signal to be detected and the signal emitted by the echo detection device will be different. This phenomenon is called Doppler interference, and the offset frequency is called Doppler frequency shift.

[0087] Understandably, underwater acoustic channels exhibit typical multipath fading, Doppler effects, and sparse structures, making them suitable for constructing parameterized channel models. Assuming the underwater acoustic channel has P primary discrete arrival paths, the impulse response of the underwater acoustic channel can be defined as:

[0088]

[0089] Among them, A p (t) and τ p (t) represents the amplitude and time delay of the p-th signal path, respectively, and τ p (t)=τ p -λ p (t)t,λ p is the Doppler scaling factor for the p-th path.

[0090] Typically, the channel amplitude and Doppler are constant over the duration of a symbol block, and the channel impulse response can be expressed by the following formula:

[0091]

[0092] The signal emitted by the echo detection equipment reaches the receiving node directly or is reflected once from the sea surface or seabed for communication. Simultaneously, it is reflected back to the echo detection equipment by the target for echo detection. Therefore, the echo signal... It can be represented as:

[0093]

[0094] in, The received ambient noise can be modeled as zero-mean additive white Gaussian noise. Since the target is stationary, the Doppler scaling factor can be estimated based on the moving speed of the integrated node. This is then used for coarse Doppler compensation of the echo signal, which can be expressed by the following formula:

[0095]

[0096] in, This refers to the frequency-independent carrier frequency offset (CFO) of the p-th signal path after Doppler coarse compensation. This represents the noise after Doppler compensation. The range profile between the detection device and the target corresponding to the detected signals with different Doppler frequency shifts is obtained by transferring the detected signal to the frequency domain, eliminating random information, and performing an inverse discrete Fourier transform. From... Figure 3 It can be seen that the higher the Doppler frequency shift value, the higher the sidelobe level, the lower the peak ratio of the main lobe and sidelobe in the distance profile, and the lower the accuracy of echo detection. Therefore, when sampling the received signal, it is necessary to introduce the Doppler frequency shift to facilitate the subsequent elimination of the influence of the Doppler frequency shift on the signal to be detected.

[0097] Optionally, the echo detection device samples the signal according to a preset time period. Optionally, the number of sampling times is preset. The echo detection device can determine the sampling time based on the preset sampling number and sample the signal at the sampling time. For example, the preset time window duration is T. w The preset number of sampling points is N. w Then the echo detection equipment can determine the time interval t = nT. w / N w Sampling signal. For simplicity, the subscript m is omitted. In this case, the time-domain baseband complex signal can be expressed as:

[0098]

[0099] Where w[n] is the sampled baseband discrete noise.

[0100] Based on the above, the signal to be detected can be represented as a matrix vector as follows:

[0101]

[0102] in, β p and τ p Let f(x) represent the amplitude coefficient, CFO, and delay of the p-th path, respectively. N represents w ×N c Zero-filled matrix of dimension Let be the discrete Fourier transform matrix, and let the nth element in the qth row be . It is zero-mean complex Gaussian white noise with variance of B(τ p D(β) is the frequency domain phase shift matrix. p Let be the phase rotation matrix, which is expressed by the following formulas:

[0103]

[0104] In this embodiment of the application, in order to obtain complete multipath information of the signal within a preset time window, an overlapping summation matrix R is constructed. ola , represented as:

[0105]

[0106] The overlapping addition matrix R ola Left-multiply the reconstructed detection signal from the above. The detection signal z is obtained for subsequent echo detection, where,

[0107] Step 202: Determine the Doppler frequency shift type of the signal to be detected based on the signal to be detected.

[0108] Since the signal to be detected includes signals corresponding to multiple signal transmission paths, the Doppler frequency shift values ​​of these signals may be the same or different. Therefore, the Doppler frequency shift type includes whether the frequency shifts of each signal component are consistent or inconsistent. When the frequency shifts of each signal component are consistent, it indicates that the signals of each signal transmission path of the signal to be detected have consistent Doppler frequency shift values. When the frequency shifts of each signal component are inconsistent, it indicates that the signals of each signal transmission path of the signal to be detected have inconsistent Doppler frequency shift values. The echo detection device can determine the Doppler frequency shift type of the acquired signal to be detected according to the preset Doppler frequency shift type discrimination conditions. The preset Doppler frequency shift type discrimination conditions can be set based on empirical values.

[0109] Step 203: Based on the Doppler frequency shift type, perform echo detection on the signal to be detected to determine whether the signal to be detected includes an echo signal.

[0110] The Doppler frequency shift type characterizes the type of Doppler interference affecting the signals along the various transmission paths of the signal to be detected. Different Doppler frequency shift types result in different Doppler interference effects on the various signals, potentially leading to different echo detection methods. (Refer to...) Figure 4 For channel responses under different Doppler frequency shift types, optionally, when the Doppler frequency shift type is that the frequency shifts of each signal component are consistent, it indicates that the signals corresponding to each signal transmission path of the signal to be detected are affected by Doppler interference in the same way. Therefore, the echo detection device needs to determine the same Doppler frequency shift value on each signal transmission path of the signal to be detected, and then perform echo detection on the signal to be detected based on each same Doppler frequency shift value. Alternatively, when the Doppler frequency shift type is that the frequency shifts of each signal component are inconsistent, it indicates that the signals corresponding to each signal transmission path of the signal to be detected are affected by Doppler interference in different ways. The echo detection device needs to determine the different Doppler frequency shift values ​​on each signal component transmission path, and then perform echo detection on the signal to be detected based on each different Doppler frequency shift value.

[0111] After the echo detection equipment performs echo detection on the signal to be detected, it can determine whether the signal to be detected includes an echo signal. If it does not include an echo signal, the signal to be detected will no longer be processed. If it does include an echo signal, the target can be successfully detected. By performing subsequent analysis and processing on the signal to be detected, parameters such as the target speed, azimuth, and distance between the target and the echo detection equipment can be effectively estimated.

[0112] The aforementioned echo detection method acquires the signal to be detected within a preset time window. Since the signal to be detected includes multiple signals corresponding to multiple signal transmission paths, and the Doppler frequency shift type includes whether the frequency shifts of each signal component are consistent or inconsistent, it is necessary to determine the Doppler frequency shift type of the signal to be detected based on the signal to be detected, and then perform echo detection on the signal to be detected according to the Doppler frequency shift type to determine whether the signal to be detected includes an echo signal. Traditional echo detection methods only select the signal from the strongest signal transmission path for echo detection, without considering the diversity of signal transmission paths in actual application scenarios, leading to the risk of missed detections. Furthermore, they do not consider the impact of Doppler interference on the signal during detection, resulting in low accuracy. In contrast, the echo detection method, apparatus, device, storage medium, and program product provided in this application perform echo detection on signals to be detected that include multiple signal transmission paths based on different Doppler frequency shift types, thus improving the accuracy of echo detection.

[0113] In one embodiment, based on Figure 2 The illustrated embodiment can be found in [reference]. Figure 5 This application's embodiments relate to the process of echo detection of a signal to be detected based on the type of Doppler frequency shift. For example... Figure 5 As shown, step 203 may include Figure 5 Steps 501 and 502 are shown.

[0114] Step 501: When the Doppler frequency shift type is that the frequency shifts of each signal component are consistent, determine the first Doppler frequency shift value corresponding to each signal component based on the signal to be detected.

[0115] When the Doppler frequency shift type is that the frequency shifts of each signal component are consistent, the signals corresponding to each signal transmission path of the signal to be detected are affected by the same Doppler interference. Therefore, the first Doppler frequency shift value corresponding to each signal component is the same, and the echo detection device can determine the first Doppler frequency shift value corresponding to each signal component based on the signal to be detected.

[0116] Regarding the method for determining the first Doppler frequency shift value using an echo detection device, in one possible implementation, the echo detection device can determine multiple estimated signals corresponding to each candidate Doppler frequency shift value based on different candidate Doppler frequency shift values, thereby obtaining the signal difference between the signal to be detected and each estimated signal, and taking the candidate Doppler frequency shift value corresponding to the estimated signal with the smallest signal difference as the first Doppler frequency shift value.

[0117] The first Doppler frequency shift value is an unknown parameter. The echo detection device needs to estimate the first Doppler frequency shift value based on the signal to be detected. In this embodiment, the echo detection device can estimate the first Doppler frequency shift value based on the least squares estimation method.

[0118] For example, the expression for the preset prediction signal is D(β). P )F H diag(d)F L h, where Let F represent the first L columns of the discrete Fourier transform matrix, and h be the channel response. Its estimated value can be expressed as: in

[0119] By substituting multiple different candidate Doppler frequency shift values ​​β into the expression for the predicted signal, the predicted signal corresponding to each candidate Doppler frequency shift value can be determined.

[0120] When the candidate Doppler frequency shift value is closer to the first Doppler frequency shift value of each signal component of the signal to be detected, the predicted signal and the signal to be detected are closer, that is, the signal difference is smaller. The signal difference between the predicted signal and the signal to be detected is numerically represented by the least squares estimation method, and the expression is as follows:

[0121]

[0122] Substituting the channel response into formula (12), the expression is:

[0123]

[0124] in,

[0125] Using formula (13), the minimum signal difference between the detected signal and each predicted signal can be determined. The predicted signal corresponding to the minimum signal difference is closest to the signal to be detected, and its corresponding candidate Doppler frequency shift value can be used as the first Doppler frequency shift value.

[0126] Step 502: Perform echo detection on the signal to be detected based on the signal to be detected and the first Doppler frequency shift value corresponding to each signal component.

[0127] The echo detection equipment obtains the first Doppler frequency shift value and can perform echo detection on the signal to be detected based on the signal to be detected and the first Doppler frequency shift value. For example, echo detection can be performed using binary hypothesis testing, or echo detection technology can be used.

[0128] Echo detection equipment performs echo detection on the signal to be detected, which can determine whether an echo signal exists in the signal. Optionally, a binary hypothesis model can be established, with two assumptions: one assumption H0 is that the signal to be detected contains both echo signal and noise, and the other assumption H1 is that the signal to be detected contains only noise. Then, the binary hypothesis model can be expressed as:

[0129]

[0130] Next, we can use the generalized likelihood ratio test to decide between these two hypotheses, and obtain the generalized likelihood ratio test formula:

[0131]

[0132] Where η' is the first ratio threshold determined according to the constant false alarm rate (CFAR) detection technique, and the numerator is... The first probability density is used to characterize the probability distribution of the presence of echo signals in the signal to be detected. The denominator is... The second probability density is used to characterize the probability distribution of the absence of echo signals in the signal to be detected. In the embodiments of this application, the second probability density is used to characterize the probability distribution of the presence of only Gaussian white noise in the signal to be detected.

[0133] In one possible implementation, the echo detection device can determine the first probability density and the second probability density corresponding to the signal to be detected based on the signal to be detected and each first Doppler frequency shift value, and perform echo detection on the signal to be detected based on the probability density ratio of the first probability density and the second probability density. Optionally, when the probability density ratio is greater than or equal to the first ratio threshold, it is determined that the signal to be detected has an echo signal. Optionally, when the probability density ratio is less than the first ratio threshold, it is determined that the signal to be detected does not have an echo signal.

[0134] In one possible implementation, for ease of calculation, formula (12) can be further derived as follows:

[0135]

[0136] Where η = lnη′.

[0137] Substituting the channel response h from the above into Formula 13, the final formula can be derived as follows:

[0138]

[0139] In this embodiment, when the echo detection device detects the signal to be detected, the first Doppler frequency shift value of each signal component, as well as the information and pilot symbols, can be substituted into formula (17) to determine whether there is an echo signal in the signal to be detected.

[0140] See Figure 6 The graph shows the detection performance of the echo detection method provided in this application and the traditional echo detection method when the Doppler frequency shift type is consistent for all signal components. The first Doppler frequency shift value is 2Hz, the false alarm probability is 0.01, and the number of subcarriers in one OFDM is N. cWith a signal-to-noise ratio of 256 and a subcarrier spacing of Δf = 4Hz, it can be seen that the echo detection method provided in this application has a higher detection probability when the signal-to-noise ratio is below -10dB.

[0141] Reference Figure 7 The graph shows the detection performance of the echo detection method provided in this application embodiment and the detection performance of the traditional echo detection method under different false alarm probabilities. The signal-to-noise ratio is fixed at -16dB, and the horizontal axis represents the number of subcarriers N. c As shown in the figure, the vertical axis represents the detection probability. The false alarm probabilities corresponding to cases 1, 2, and 3 are different. It can be seen that, when the false alarm probability and the number of subcarriers are the same, the echo detection method provided in this application embodiment has a higher detection probability and higher accuracy.

[0142] In one embodiment, based on Figure 2 The illustrated embodiment can be found in [reference]. Figure 8 This application's embodiments relate to the process of echo detection of a signal to be detected based on the type of Doppler frequency shift. For example... Figure 8 As shown, step 203 may include Figure 8 Steps 801 and 802 are shown.

[0143] Step 801: When the Doppler frequency shift type is that the frequency shifts of each signal component are inconsistent, determine at least one effective path from each signal transmission path according to each signal component.

[0144] When the Doppler frequency shift type is that the frequency shifts of each signal component are inconsistent, it indicates that the signals corresponding to each signal transmission path of the signal to be detected are affected by Doppler interference differently. Therefore, the echo detection equipment needs to process and analyze the signals of each channel transmission path. However, since the signals corresponding to each signal transmission path are different, the echo detection equipment needs to select at least one effective path from each signal transmission path, and the signal strength corresponding to the effective path can reach a certain threshold.

[0145] Regarding the method for determining the effective path, in one possible implementation, the echo detection device can determine the second amplitude value corresponding to each signal component based on each signal component, and take the signal transmission path corresponding to the signal whose second amplitude value is greater than a preset amplitude value threshold as the effective path. The second amplitude value is the amplitude coefficient of each signal component corresponding to each signal component transmission path.

[0146] At this point, the signal z, composed of the signals corresponding to each effective path, is... 有效 It can be represented as:

[0147]

[0148] Where i is the index of the valid signal and P is the number of valid signals.

[0149] Step 802: Based on the multiple valid signals corresponding to each valid path, perform echo detection on the signal to be detected.

[0150] After determining each valid signal, the echo detection device can perform echo detection on the signal to be detected based on each valid signal. Optionally, the echo detection device can detect the energy value of each valid signal to determine whether the signal to be detected includes an echo signal. Alternatively, the echo detection device can detect the signal strength of each valid signal to determine whether the signal to be detected includes an echo signal.

[0151] In one embodiment, based on Figure 8 The illustrated embodiment can be found in [reference]. Figure 9 This application's embodiments relate to the process of performing echo detection on a signal to be detected based on multiple valid signals corresponding to each valid path. For example... Figure 9 As shown, step 802 may include Figure 9 Steps 901 to 903 are shown.

[0152] Step 901: Obtain the second Doppler frequency shift value corresponding to each valid signal based on each valid signal.

[0153] Since the Doppler frequency shift type is characterized by inconsistent frequency shifts among signal components, the second Doppler frequency shift values ​​corresponding to each effective signal are different. The method for obtaining the second Doppler frequency shift values ​​corresponding to each effective signal can be reconstructed by setting the second Doppler frequency shift value as an unknown parameter. Therefore, for the second Doppler frequency shift value corresponding to the i-th effective signal... The expression is:

[0154]

[0155] in, This is the reconstructed echo of the (i-1)th valid signal.

[0156] Step 902: Determine the distance data corresponding to each valid signal based on each valid signal and each second Doppler frequency shift value.

[0157] The distance data includes a first amplitude value, which is used to characterize the maximum radiation intensity of the effective signal.

[0158] The distance data can be obtained from each valid signal, and the distance profile between the echo detection device and the target corresponding to each valid signal is given by the distance profile r corresponding to the i-th valid signal. i It can be represented as:

[0159]

[0160] That is, perform a Discrete Fourier Transform on the i-th valid signal. This represents the division operator.

[0161] The horizontal axis of the distance profile represents the time delay corresponding to the effective signal, and the vertical axis represents the radiation intensity value of the effective signal. The value with the maximum radiation intensity is the first amplitude value corresponding to the effective signal. Therefore, the first amplitude value corresponding to the i-th effective signal is:

[0162]

[0163] in, This is the amplitude delay corresponding to the first amplitude value.

[0164] Step 903: Perform echo detection on the signal to be detected based on the distance data.

[0165] In one possible implementation, the echo detection device can sum the first amplitude values ​​corresponding to each valid signal to obtain the sum of amplitude values. The specific detection formula is as follows:

[0166]

[0167] Where H1 is the assumption that the signal to be detected includes an echo signal, H0 is the assumption that the signal to be detected includes an echo signal, and η AAC In this embodiment of the application, if the sum of the amplitude values ​​is greater than or equal to the preset sum of the threshold values, it is determined that the signal to be detected has an echo signal; if the sum of the amplitude values ​​is less than the preset sum of the threshold values, it is determined that the signal to be detected does not have an echo signal.

[0168] In another possible implementation, the echo detection device can calculate the energy value of each valid signal to perform echo detection on the signal to be detected. In this embodiment, the distance data also includes amplitude delay. The amplitude value is the value of the first amplitude value on the horizontal axis corresponding to the distance profile. Then, the echo detection device can determine the first energy value corresponding to each valid signal based on the amplitude value, amplitude delay and second Doppler frequency shift value corresponding to each valid signal, and obtain the energy value and value of each first energy value. Based on the signal to be detected, the device can determine the second energy value corresponding to the signal to be detected.

[0169] The higher the proportion of the sum of energy values ​​to the second energy value, the greater the probability of an echo signal in the signal to be detected. Therefore, the echo detection equipment needs to determine the energy ratio of the sum of energy values ​​to the second energy value to obtain the detection formula:

[0170]

[0171] Where, η ERTo preset a second ratio threshold, if the energy ratio of the sum of energy values ​​to the second energy value is greater than or equal to the second ratio threshold, it is determined that the signal to be detected has an echo signal; if the energy ratio of the sum of energy values ​​to the second energy value is less than the second ratio threshold, it is determined that the signal to be detected does not have an echo signal.

[0172] The echo detection methods described above, implemented in two different ways, represent two parallel detection schemes with varying detection probabilities. See [link to relevant documentation]. Figure 10 When the Doppler frequency shift type is such that the frequency shifts of each signal component are inconsistent, the number of subcarriers N is set. c The value is 512, Δf = 4Hz, and the false alarm probability is set to 0.01. It can be seen that the more valid signals identified, the higher the detection probability and the higher the detection accuracy. Echo detection based on energy values ​​has a higher detection probability and higher accuracy than echo detection based on amplitude and value.

[0173] See Figure 11 The diagram shows the detection probability of two different implementation methods when the number of effective signals is the same, with the signal-to-noise ratio fixed at -14dB. It can be seen that when the number of known effective signals increases, echo detection based on energy value has a higher detection probability and higher detection accuracy than echo detection based on amplitude and value.

[0174] See Figure 12 The diagram shows the detection probability of two different implementation methods with the same number of subcarriers. The false alarm rate is 0.01, the signal-to-noise ratio is fixed at -14dB, and the carrier spacing is 4Hz. It can be seen that the detection probability is higher as the number of subcarriers increases. The detection probability of echo detection based on energy value is higher than that of echo detection based on amplitude and value.

[0175] See Figure 13 The diagram shows the detection probability of two different implementation methods when the subcarrier spacing is the same. It can be seen that the detection probability is higher as the subcarrier spacing increases, and the detection probability of echo detection based on energy value is higher than that of echo detection based on amplitude and value.

[0176] In one embodiment, an echo detection method is provided, the method comprising the following steps:

[0177] Step a: Acquire the signal to be detected within a preset time window.

[0178] The signals to be detected include multiple signals corresponding to multiple signal transmission paths.

[0179] Step b: Determine the Doppler frequency shift type of the signal to be detected based on the signal to be detected.

[0180] Among them, the Doppler frequency shift types include those where the frequency shifts of each signal component are consistent or those where the frequency shifts of each signal component are inconsistent.

[0181] Step c: When the Doppler frequency shift type is that the frequency shift of each signal component is consistent, determine multiple predicted signals corresponding to each candidate Doppler frequency shift value based on different candidate Doppler frequency shift values.

[0182] Step d: Obtain the signal difference between the signal to be detected and each predicted signal.

[0183] Step e: The candidate Doppler frequency shift value corresponding to the estimated signal with the smallest signal difference is taken as the first Doppler frequency shift value.

[0184] Among them, the first Doppler frequency shift value corresponding to each signal component is the same.

[0185] Step f: Determine the first probability density and the second probability density corresponding to the signal to be detected based on the signal to be detected and each first Doppler frequency shift value.

[0186] The first probability density is used to characterize the probability distribution of the presence of an echo signal in the signal to be detected, and the second probability density is used to characterize the probability distribution of the absence of an echo signal in the signal to be detected.

[0187] Step g: When the probability density ratio is greater than or equal to the first ratio threshold, it is determined that the signal to be detected has an echo signal.

[0188] Step h: If the probability density ratio is less than the first ratio threshold, it is determined that there is no echo signal in the signal to be detected.

[0189] Step i: When the Doppler frequency shift type is that the frequency shifts of each signal component are inconsistent, determine the second amplitude value corresponding to each signal component based on each signal component.

[0190] Step j: The signal transmission path corresponding to the signal whose second amplitude value is greater than the preset amplitude value threshold is taken as the valid path.

[0191] Step k: Based on each valid signal, obtain the second Doppler frequency shift value corresponding to each valid signal.

[0192] The second Doppler frequency shift values ​​corresponding to each valid signal are different.

[0193] Step 1: Determine the distance data corresponding to each valid signal based on each valid signal and each second Doppler frequency shift value.

[0194] The distance data includes a first amplitude value, which is used to characterize the maximum radiation intensity of the effective signal.

[0195] Step m: Add the first amplitude values ​​corresponding to each valid signal to obtain the amplitude sum.

[0196] In step n, if the amplitude value and sum value are greater than or equal to the preset sum value threshold, it is determined that the signal to be detected has an echo signal.

[0197] Step o: If the amplitude value and sum value are less than the preset sum value threshold, it is determined that there is no echo signal in the signal to be detected.

[0198] The distance data also includes amplitude delay.

[0199] Step p: Determine the first energy value corresponding to each valid signal based on the amplitude value, amplitude delay, and second Doppler frequency shift value corresponding to each valid signal, and obtain the energy value and value of each first energy value.

[0200] Step q: Determine the second energy value corresponding to the signal to be detected based on the signal to be detected.

[0201] In step r, if the energy ratio of the sum of the energy values ​​to the second energy value is greater than or equal to the second ratio threshold, then it is determined that the signal to be detected has an echo signal.

[0202] Step s: If the energy ratio of the sum of the energy values ​​to the second energy value is less than the second ratio threshold, then it is determined that the signal to be detected does not have an echo signal.

[0203] It should be understood that although the steps in the flowcharts of the embodiments described above are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowcharts of the embodiments described above may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the steps or stages of other steps.

[0204] Based on the same inventive concept, this application also provides an echo detection device for implementing the echo detection method described above. The solution provided by this device is similar to the solution described in the above method; therefore, the specific limitations in one or more echo detection device embodiments provided below can be found in the limitations of the echo detection method described above, and will not be repeated here.

[0205] In one exemplary embodiment, such as Figure 14As shown, an echo detection device is provided, including: an acquisition module 1401, a determination module 1402, and an L module, wherein:

[0206] Acquisition module 1401 is used to acquire a signal to be detected within a preset time window, wherein the signal to be detected includes multiple signals corresponding to multiple signal transmission paths;

[0207] The determining module 1402 is used to determine the Doppler frequency shift type of the signal to be detected based on the signal to be detected. The Doppler frequency shift type includes the frequency shift of each signal component being consistent or the frequency shift of each signal component being inconsistent.

[0208] The echo detection module 1403 is used to perform echo detection on the signal to be detected according to the Doppler frequency shift type, so as to determine whether the signal to be detected includes an echo signal.

[0209] In one embodiment, the echo detection module 1403 includes:

[0210] The first Doppler frequency shift value determination unit is used to determine the first Doppler frequency shift value corresponding to each of the signal components based on the signal to be detected when the Doppler frequency shift type is that the frequency shifts of each of the signal components are consistent, and the first Doppler frequency shift values ​​corresponding to each of the signal components are the same;

[0211] A consistent echo detection unit is used to perform echo detection on the signal to be detected based on the signal to be detected and the first Doppler frequency shift value corresponding to each of the signal components.

[0212] In one embodiment, the consistent echo detection unit is further configured to:

[0213] Based on the signal to be detected and each of the first Doppler frequency shift values, a first probability density and a second probability density corresponding to the signal to be detected are determined. The first probability density is used to characterize the probability distribution of the presence of the echo signal in the signal to be detected, and the second probability density is used to characterize the probability distribution of the absence of the echo signal in the signal to be detected.

[0214] The signal to be detected is subjected to echo detection based on the probability density ratio of the first probability density and the second probability density.

[0215] In one embodiment, the consistent echo detection unit is also used for:

[0216] When the probability density ratio is greater than or equal to the first ratio threshold, it is determined that the signal to be detected contains the echo signal;

[0217] If the probability density ratio is less than the first ratio threshold, it is determined that the signal to be detected does not contain the echo signal.

[0218] In one embodiment, the first Doppler frequency shift value determination unit is further configured to:

[0219] Based on different candidate Doppler frequency shift values, multiple estimated signals corresponding to each candidate Doppler frequency shift value are determined;

[0220] Obtain the signal difference between the signal to be detected and each of the estimated signals;

[0221] The candidate Doppler frequency shift value corresponding to the predicted signal with the smallest signal difference is taken as the first Doppler frequency shift value.

[0222] In one embodiment, the echo detection module 1403 includes:

[0223] An effective path determination unit is configured to determine at least one effective path from each of the signal transmission paths based on each of the signal components when the Doppler frequency shift type is such that the frequency shifts of each of the signal components are inconsistent.

[0224] The inconsistency echo detection unit is used to perform echo detection on the signal to be detected based on multiple valid signals corresponding to each valid path.

[0225] In one embodiment, the inconsistency echo detection unit is further configured to:

[0226] Based on each of the effective signals, a second Doppler frequency shift value corresponding to each of the effective signals is obtained, and the second Doppler frequency shift values ​​corresponding to each of the effective signals are different;

[0227] Based on each of the effective signals and each of the second Doppler frequency shift values, distance data corresponding to each of the effective signals is determined. The distance data includes a first amplitude value, which is used to characterize the maximum radiation intensity of the effective signal.

[0228] Based on the distance data, echo detection is performed on the signal to be detected.

[0229] In one embodiment, the inconsistency echo detection unit is further configured to:

[0230] Add the first amplitude values ​​corresponding to each of the valid signals to obtain the amplitude value and the sum value;

[0231] If the amplitude value is greater than or equal to a preset threshold value, then it is determined that the signal to be detected has an echo signal.

[0232] If the amplitude value is less than the preset sum value threshold, it is determined that there is no echo signal in the signal to be detected.

[0233] In one embodiment, the inconsistency echo detection unit is further configured to:

[0234] Based on the amplitude value, amplitude delay, and second Doppler frequency shift value corresponding to each of the effective signals, determine the first energy value corresponding to each of the effective signals, and obtain the energy value and value of each of the first energy values;

[0235] Based on the signal to be detected, determine the second energy value corresponding to the signal to be detected;

[0236] If the energy ratio of the sum of the energy values ​​to the second energy value is greater than or equal to the second ratio threshold, then it is determined that the signal to be detected has an echo signal.

[0237] If the energy ratio of the sum of the energy values ​​to the second energy value is less than the second ratio threshold, then it is determined that the signal to be detected does not have an echo signal.

[0238] In one embodiment, the effective path determination unit is further configured to:

[0239] Based on each of the signal components, determine the second amplitude value corresponding to each of the signal components;

[0240] The signal transmission path corresponding to the signal whose second amplitude value is greater than the preset amplitude value threshold is taken as the valid path.

[0241] Each module in the aforementioned echo detection device can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in the processor of a computer device in hardware form or independent of it, or stored in the memory of a computer device in software form, so that the processor can call and execute the corresponding operations of each module.

[0242] In one exemplary embodiment, a computer device is provided, which may be a server, and its internal structure diagram may be as follows: Figure 15As shown, this computer device includes a processor, memory, input / output (I / O) interfaces, and a communication interface. The processor, memory, and I / O interfaces are connected via a system bus, and the communication interface is also connected to the system bus via the I / O interfaces. The processor provides computational and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system, computer programs, and a database. The internal memory provides the environment for the operation of the operating system and computer programs stored in the non-volatile storage media. The database stores echo detection data. The I / O interfaces are used for exchanging information between the processor and external devices. The communication interface is used for communication with external terminals via a network connection. When the computer program is executed by the processor, it implements an echo detection method.

[0243] Those skilled in the art will understand that Figure 15 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0244] In one exemplary embodiment, a computer device is provided, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to perform the following steps:

[0245] Acquire the signal to be detected within a preset time window; the signal to be detected includes multiple signals corresponding to multiple signal transmission paths.

[0246] Based on the signal to be detected, the Doppler frequency shift type of the signal to be detected is determined, wherein the Doppler frequency shift type includes the frequency shift of each signal component being consistent or the frequency shift of each signal component being inconsistent;

[0247] Based on the Doppler frequency shift type, echo detection is performed on the signal to be detected to determine whether the signal to be detected includes an echo signal.

[0248] In one embodiment, the processor, when executing a computer program, also performs the following steps:

[0249] When the Doppler frequency shift type is that the frequency shifts of each of the signal components are consistent, the first Doppler frequency shift value corresponding to each of the signal components is determined according to the signal to be detected, and the first Doppler frequency shift value corresponding to each of the signal components is the same;

[0250] Echo detection is performed on the signal to be detected based on the signal to be detected and the first Doppler frequency shift value corresponding to each of the signal components.

[0251] In one embodiment, the processor, when executing a computer program, also performs the following steps:

[0252] Based on the signal to be detected and each of the first Doppler frequency shift values, a first probability density and a second probability density corresponding to the signal to be detected are determined. The first probability density is used to characterize the probability distribution of the presence of the echo signal in the signal to be detected, and the second probability density is used to characterize the probability distribution of the absence of the echo signal in the signal to be detected.

[0253] The signal to be detected is subjected to echo detection based on the probability density ratio of the first probability density and the second probability density.

[0254] In one embodiment, the processor, when executing a computer program, also performs the following steps:

[0255] When the probability density ratio is greater than or equal to the first ratio threshold, it is determined that the signal to be detected contains the echo signal;

[0256] If the probability density ratio is less than the first ratio threshold, it is determined that the signal to be detected does not contain the echo signal.

[0257] In one embodiment, the processor, when executing a computer program, also performs the following steps:

[0258] Based on different candidate Doppler frequency shift values, multiple estimated signals corresponding to each candidate Doppler frequency shift value are determined;

[0259] Obtain the signal difference between the signal to be detected and each of the estimated signals;

[0260] The candidate Doppler frequency shift value corresponding to the predicted signal with the smallest signal difference is taken as the first Doppler frequency shift value.

[0261] In one embodiment, the processor, when executing a computer program, also performs the following steps:

[0262] When the Doppler frequency shift type is such that the frequency shifts of each of the signal components are inconsistent, at least one effective path is determined from each of the signal transmission paths based on each of the signal components;

[0263] Echo detection is performed on the signal to be detected based on multiple valid signals corresponding to each valid path.

[0264] In one embodiment, the processor, when executing a computer program, also performs the following steps:

[0265] Based on each of the effective signals, a second Doppler frequency shift value corresponding to each of the effective signals is obtained, and the second Doppler frequency shift values ​​corresponding to each of the effective signals are different;

[0266] Based on each of the effective signals and each of the second Doppler frequency shift values, distance data corresponding to each of the effective signals is determined. The distance data includes a first amplitude value, which is used to characterize the maximum radiation intensity of the effective signal.

[0267] Based on the distance data, echo detection is performed on the signal to be detected.

[0268] In one embodiment, the processor, when executing a computer program, also performs the following steps:

[0269] Add the first amplitude values ​​corresponding to each of the valid signals to obtain the amplitude value and the sum value;

[0270] If the amplitude value is greater than or equal to a preset threshold value, then it is determined that the signal to be detected has an echo signal.

[0271] If the amplitude value is less than the preset sum value threshold, it is determined that there is no echo signal in the signal to be detected.

[0272] In one embodiment, the distance data further includes an amplitude delay, and the processor, when executing the computer program, further implements the following steps:

[0273] Based on the amplitude value, amplitude delay, and second Doppler frequency shift value corresponding to each of the effective signals, determine the first energy value corresponding to each of the effective signals, and obtain the energy value and value of each of the first energy values;

[0274] Based on the signal to be detected, determine the second energy value corresponding to the signal to be detected;

[0275] If the energy ratio of the sum of the energy values ​​to the second energy value is greater than or equal to the second ratio threshold, then it is determined that the signal to be detected has an echo signal.

[0276] If the energy ratio of the sum of the energy values ​​to the second energy value is less than the second ratio threshold, then it is determined that the signal to be detected does not have an echo signal.

[0277] In one embodiment, the processor, when executing a computer program, also performs the following steps:

[0278] Based on each of the signal components, determine the second amplitude value corresponding to each of the signal components;

[0279] The signal transmission path corresponding to the signal whose second amplitude value is greater than the preset amplitude value threshold is taken as the valid path.

[0280] In one embodiment, a computer-readable storage medium is provided having a computer program stored thereon, the computer program performing the following steps when executed by a processor:

[0281] Acquire the signal to be detected within a preset time window; the signal to be detected includes multiple signals corresponding to multiple signal transmission paths.

[0282] Based on the signal to be detected, the Doppler frequency shift type of the signal to be detected is determined, wherein the Doppler frequency shift type includes the frequency shift of each signal component being consistent or the frequency shift of each signal component being inconsistent;

[0283] Based on the Doppler frequency shift type, echo detection is performed on the signal to be detected to determine whether the signal to be detected includes an echo signal.

[0284] In one embodiment, when the computer program is executed by a processor, it further performs the following steps:

[0285] When the Doppler frequency shift type is that the frequency shifts of each of the signal components are consistent, the first Doppler frequency shift value corresponding to each of the signal components is determined according to the signal to be detected, and the first Doppler frequency shift value corresponding to each of the signal components is the same;

[0286] Echo detection is performed on the signal to be detected based on the signal to be detected and the first Doppler frequency shift value corresponding to each of the signal components.

[0287] In one embodiment, when the computer program is executed by a processor, it also performs the following steps:

[0288] Based on the signal to be detected and each of the first Doppler frequency shift values, a first probability density and a second probability density corresponding to the signal to be detected are determined. The first probability density is used to characterize the probability distribution of the presence of the echo signal in the signal to be detected, and the second probability density is used to characterize the probability distribution of the absence of the echo signal in the signal to be detected.

[0289] The signal to be detected is subjected to echo detection based on the probability density ratio of the first probability density and the second probability density.

[0290] In one embodiment, when the computer program is executed by a processor, it further performs the following steps:

[0291] When the probability density ratio is greater than or equal to the first ratio threshold, it is determined that the signal to be detected contains the echo signal;

[0292] If the probability density ratio is less than the first ratio threshold, it is determined that the signal to be detected does not contain the echo signal.

[0293] In one embodiment, when the computer program is executed by a processor, it further performs the following steps:

[0294] Based on different candidate Doppler frequency shift values, multiple estimated signals corresponding to each candidate Doppler frequency shift value are determined;

[0295] Obtain the signal difference between the signal to be detected and each of the estimated signals;

[0296] The candidate Doppler frequency shift value corresponding to the predicted signal with the smallest signal difference is taken as the first Doppler frequency shift value.

[0297] In one embodiment, when the computer program is executed by a processor, it further performs the following steps:

[0298] When the Doppler frequency shift type is such that the frequency shifts of each of the signal components are inconsistent, at least one effective path is determined from each of the signal transmission paths based on each of the signal components;

[0299] Echo detection is performed on the signal to be detected based on multiple valid signals corresponding to each valid path.

[0300] In one embodiment, when the computer program is executed by a processor, it further performs the following steps:

[0301] Based on each of the effective signals, a second Doppler frequency shift value corresponding to each of the effective signals is obtained, and the second Doppler frequency shift values ​​corresponding to each of the effective signals are different;

[0302] Based on each of the effective signals and each of the second Doppler frequency shift values, distance data corresponding to each of the effective signals is determined. The distance data includes a first amplitude value, which is used to characterize the maximum radiation intensity of the effective signal.

[0303] Based on the distance data, echo detection is performed on the signal to be detected.

[0304] In one embodiment, when the computer program is executed by a processor, it further performs the following steps:

[0305] Add the first amplitude values ​​corresponding to each of the valid signals to obtain the amplitude value and the sum value;

[0306] If the amplitude value is greater than or equal to a preset threshold value, then it is determined that the signal to be detected has an echo signal.

[0307] If the amplitude value is less than the preset sum value threshold, it is determined that there is no echo signal in the signal to be detected.

[0308] In one embodiment, the distance data further includes an amplitude delay, and the computer program, when executed by a processor, further implements the following steps:

[0309] Based on the amplitude value, amplitude delay, and second Doppler frequency shift value corresponding to each of the effective signals, determine the first energy value corresponding to each of the effective signals, and obtain the energy value and value of each of the first energy values;

[0310] Based on the signal to be detected, determine the second energy value corresponding to the signal to be detected;

[0311] If the energy ratio of the sum of the energy values ​​to the second energy value is greater than or equal to the second ratio threshold, then it is determined that the signal to be detected has an echo signal.

[0312] If the energy ratio of the sum of the energy values ​​to the second energy value is less than the second ratio threshold, then it is determined that the signal to be detected does not have an echo signal.

[0313] In one embodiment, when the computer program is executed by a processor, it further performs the following steps:

[0314] Based on each of the signal components, determine the second amplitude value corresponding to each of the signal components;

[0315] The signal transmission path corresponding to the signal whose second amplitude value is greater than the preset amplitude value threshold is taken as the valid path.

[0316] In one embodiment, a computer program product is provided, including a computer program that, when executed by a processor, performs the following steps:

[0317] Acquire the signal to be detected within a preset time window; the signal to be detected includes multiple signals corresponding to multiple signal transmission paths.

[0318] Based on the signal to be detected, the Doppler frequency shift type of the signal to be detected is determined, wherein the Doppler frequency shift type includes the frequency shift of each signal component being consistent or the frequency shift of each signal component being inconsistent;

[0319] Based on the Doppler frequency shift type, echo detection is performed on the signal to be detected to determine whether the signal to be detected includes an echo signal.

[0320] In one embodiment, when the computer program is executed by a processor, it further performs the following steps:

[0321] When the Doppler frequency shift type is that the frequency shifts of each of the signal components are consistent, the first Doppler frequency shift value corresponding to each of the signal components is determined according to the signal to be detected, and the first Doppler frequency shift value corresponding to each of the signal components is the same;

[0322] Echo detection is performed on the signal to be detected based on the signal to be detected and the first Doppler frequency shift value corresponding to each of the signal components.

[0323] In one embodiment, when the computer program is executed by a processor, it further performs the following steps:

[0324] Based on the signal to be detected and each of the first Doppler frequency shift values, a first probability density and a second probability density corresponding to the signal to be detected are determined. The first probability density is used to characterize the probability distribution of the presence of the echo signal in the signal to be detected, and the second probability density is used to characterize the probability distribution of the absence of the echo signal in the signal to be detected.

[0325] The signal to be detected is subjected to echo detection based on the probability density ratio of the first probability density and the second probability density.

[0326] In one embodiment, when the computer program is executed by a processor, it further performs the following steps:

[0327] When the probability density ratio is greater than or equal to the first ratio threshold, it is determined that the signal to be detected contains the echo signal;

[0328] If the probability density ratio is less than the first ratio threshold, it is determined that the signal to be detected does not contain the echo signal.

[0329] In one embodiment, when the computer program is executed by a processor, it further performs the following steps:

[0330] Based on different candidate Doppler frequency shift values, multiple estimated signals corresponding to each candidate Doppler frequency shift value are determined;

[0331] Obtain the signal difference between the signal to be detected and each of the estimated signals;

[0332] The candidate Doppler frequency shift value corresponding to the predicted signal with the smallest signal difference is taken as the first Doppler frequency shift value.

[0333] In one embodiment, when the computer program is executed by a processor, it further performs the following steps:

[0334] When the Doppler frequency shift type is such that the frequency shifts of each of the signal components are inconsistent, at least one effective path is determined from each of the signal transmission paths based on each of the signal components;

[0335] Echo detection is performed on the signal to be detected based on multiple valid signals corresponding to each valid path.

[0336] In one embodiment, when the computer program is executed by a processor, it further performs the following steps:

[0337] Based on each of the effective signals, a second Doppler frequency shift value corresponding to each of the effective signals is obtained, and the second Doppler frequency shift values ​​corresponding to each of the effective signals are different;

[0338] Based on each of the effective signals and each of the second Doppler frequency shift values, distance data corresponding to each of the effective signals is determined. The distance data includes a first amplitude value, which is used to characterize the maximum radiation intensity of the effective signal.

[0339] Based on the distance data, echo detection is performed on the signal to be detected.

[0340] In one embodiment, when the computer program is executed by a processor, it further performs the following steps:

[0341] Add the first amplitude values ​​corresponding to each of the valid signals to obtain the amplitude value and the sum value;

[0342] If the amplitude value is greater than or equal to a preset threshold value, then it is determined that the signal to be detected has an echo signal.

[0343] If the amplitude value is less than the preset sum value threshold, it is determined that there is no echo signal in the signal to be detected.

[0344] In one embodiment, the distance data further includes an amplitude delay, and the computer program, when executed by a processor, further implements the following steps:

[0345] Based on the amplitude value, amplitude delay, and second Doppler frequency shift value corresponding to each of the effective signals, determine the first energy value corresponding to each of the effective signals, and obtain the energy value and value of each of the first energy values;

[0346] Based on the signal to be detected, determine the second energy value corresponding to the signal to be detected;

[0347] If the energy ratio of the sum of the energy values ​​to the second energy value is greater than or equal to the second ratio threshold, then it is determined that the signal to be detected has an echo signal.

[0348] If the energy ratio of the sum of the energy values ​​to the second energy value is less than the second ratio threshold, then it is determined that the signal to be detected does not have an echo signal.

[0349] In one embodiment, when the computer program is executed by a processor, it further performs the following steps:

[0350] Based on each of the signal components, determine the second amplitude value corresponding to each of the signal components;

[0351] The signal transmission path corresponding to the signal whose second amplitude value is greater than the preset amplitude value threshold is taken as the valid path.

[0352] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, data stored, data displayed, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of the relevant data must comply with relevant regulations.

[0353] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM). The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, etc., and are not limited to these.

[0354] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0355] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A target echo detection method for a multi-carrier underwater acoustic communication and sensing integrated system, characterized in that, The method includes: Acquire the signal to be detected within a preset time window; the signal to be detected includes multiple signals corresponding to multiple signal transmission paths. Based on the signal to be detected, the Doppler frequency shift type of the signal to be detected is determined. The Doppler frequency shift type includes the frequency shift of each signal component being consistent or the frequency shift of each signal component being inconsistent. When the Doppler frequency shift type is that the frequency shifts of each of the signal components are consistent, a first Doppler frequency shift value corresponding to each of the signal components is determined according to the signal to be detected, and the first Doppler frequency shift values ​​corresponding to each of the signal components are the same; based on the signal to be detected and the first Doppler frequency shift values ​​corresponding to each of the signal components, echo detection is performed on the signal to be detected to determine whether the signal to be detected includes an echo signal. When the Doppler frequency shift type is such that the frequency shifts of each of the signal components are inconsistent, at least one valid path is determined from each of the signal transmission paths based on each of the signal components; based on the multiple valid signals corresponding to each of the valid paths, echo detection is performed on the signal to be detected to determine whether the signal to be detected includes the echo signal.

2. The method according to claim 1, characterized in that, The step of performing echo detection on the signal to be detected based on the signal to be detected and the first Doppler frequency shift value corresponding to each of the signal components includes: Based on the signal to be detected and each of the first Doppler frequency shift values, a first probability density and a second probability density corresponding to the signal to be detected are determined. The first probability density is used to characterize the probability distribution of the presence of the echo signal in the signal to be detected, and the second probability density is used to characterize the probability distribution of the absence of the echo signal in the signal to be detected. The signal to be detected is subjected to echo detection based on the probability density ratio of the first probability density and the second probability density.

3. The method according to claim 2, characterized in that, The step of performing echo detection on the signal to be detected based on the probability density ratio of the first probability density and the second probability density includes: When the probability density ratio is greater than or equal to the first ratio threshold, it is determined that the signal to be detected contains the echo signal; If the probability density ratio is less than the first ratio threshold, it is determined that the signal to be detected does not contain the echo signal.

4. The method according to claim 2 or 3, characterized in that, The step of determining the first Doppler frequency shift value corresponding to each signal component based on the signal to be detected includes: Based on different candidate Doppler frequency shift values, multiple estimated signals corresponding to each candidate Doppler frequency shift value are determined; Obtain the signal difference between the signal to be detected and each of the estimated signals; The candidate Doppler frequency shift value corresponding to the predicted signal with the smallest signal difference is taken as the first Doppler frequency shift value.

5. The method according to claim 1, characterized in that, The step of performing echo detection on the signal to be detected based on multiple valid signals corresponding to each valid path includes: Based on each of the effective signals, a second Doppler frequency shift value corresponding to each of the effective signals is obtained, and the second Doppler frequency shift values ​​corresponding to each of the effective signals are different; Based on each of the effective signals and each of the second Doppler frequency shift values, distance data corresponding to each of the effective signals is determined. The distance data includes a first amplitude value, which is used to characterize the maximum radiation intensity of the effective signal. Based on the distance data, echo detection is performed on the signal to be detected.

6. The method according to claim 5, characterized in that, The step of performing echo detection on the signal to be detected based on the distance data includes: Add the first amplitude values ​​corresponding to each of the valid signals to obtain the amplitude value and the sum value; If the amplitude value is greater than or equal to a preset threshold value, then it is determined that the signal to be detected has an echo signal. If the amplitude value is less than the preset sum value threshold, it is determined that there is no echo signal in the signal to be detected.

7. The method according to claim 6, characterized in that, The distance data also includes amplitude delay, and the echo detection of the signal to be detected based on each of the distance data includes: Based on the amplitude value, amplitude delay, and second Doppler frequency shift value corresponding to each valid signal, determine the likelihood ratio test statistic corresponding to each valid signal; If the likelihood ratio test statistic is greater than or equal to the second ratio threshold, then it is determined that the signal to be detected has an echo signal. If the likelihood ratio test statistic is less than the second ratio threshold, then it is determined that the signal to be detected does not have an echo signal.

8. The method according to any one of claims 5-7, characterized in that, Determining at least one valid path from each of the signal transmission paths based on each of the signal components includes: Based on each of the signal components, determine the second amplitude value corresponding to each of the signal components; The signal transmission path corresponding to the signal whose second amplitude value is greater than the preset amplitude value threshold is taken as the valid path.

9. A device for target echo detection in a multi-carrier underwater acoustic communication and sensing integrated system, characterized in that, The device includes: The acquisition module is used to acquire a signal to be detected within a preset time window, wherein the signal to be detected includes multiple signals corresponding to multiple signal transmission paths; The determining module is used to determine the Doppler frequency shift type of the signal to be detected based on the signal to be detected. The Doppler frequency shift type includes the frequency shift of each signal component being consistent or the frequency shift of each signal component being inconsistent. The echo detection module is used to determine, when the Doppler frequency shift type is such that the frequency shifts of each of the signal components are consistent, a first Doppler frequency shift value corresponding to each of the signal components based on the signal to be detected, wherein the first Doppler frequency shift values ​​corresponding to each of the signal components are the same; and to perform echo detection on the signal to be detected based on the signal to be detected and the first Doppler frequency shift values ​​corresponding to each of the signal components to determine whether the signal to be detected includes an echo signal. The echo detection module is further configured to, when the Doppler frequency shift type is such that the frequency shifts of each of the signal components are inconsistent, determine at least one valid path from each of the signal transmission paths based on each of the signal components; and perform echo detection on the signal to be detected based on the multiple valid signals corresponding to each of the valid paths, so as to determine whether the signal to be detected includes the echo signal.

10. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the method according to any one of claims 1 to 8.

11. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 8.

12. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 8.

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