CN117192556A - Underwater target distance accurate estimation method based on simple wave mode group delay - Google Patents
Underwater target distance accurate estimation method based on simple wave mode group delay Download PDFInfo
- Publication number
- CN117192556A CN117192556A CN202311174613.2A CN202311174613A CN117192556A CN 117192556 A CN117192556 A CN 117192556A CN 202311174613 A CN202311174613 A CN 202311174613A CN 117192556 A CN117192556 A CN 117192556A
- Authority
- CN
- China
- Prior art keywords
- time
- order
- mode
- frequency
- deltat
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000000034 method Methods 0.000 title claims abstract description 17
- 238000004364 calculation method Methods 0.000 claims abstract description 10
- 239000006185 dispersion Substances 0.000 claims description 19
- 238000004458 analytical method Methods 0.000 claims description 3
- 230000001902 propagating effect Effects 0.000 claims description 3
- 238000001228 spectrum Methods 0.000 claims description 2
- 238000006467 substitution reaction Methods 0.000 claims description 2
- 230000010365 information processing Effects 0.000 abstract description 2
- 238000003491 array Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 238000012217 deletion Methods 0.000 description 1
- 230000037430 deletion Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000005284 excitation Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Landscapes
- Measurement Of Velocity Or Position Using Acoustic Or Ultrasonic Waves (AREA)
Abstract
The invention discloses an accurate underwater target distance estimation method based on a simple wave mode group delay, and belongs to the technical field of signal and information processing. According to the method, the characteristic that the time delay difference of the adjacent two-order modes of the time-frequency distribution of the simple wave reaches the hydrophone is equal-difference series is utilized, the time value of each-order mode reaching the hydrophone is obtained through the time-frequency distribution of a received signal, the time delay difference of the last-order mode and the first-order mode is compared with the calculation value of an equal-difference series summation formula, the corresponding condition of the time value and the mode order is determined, and then each parameter is substituted into an underwater target distance calculation formula, so that the accurate estimation of the distance is realized. The method and the device can judge whether the time-frequency distribution of the received signal has the condition of modal missing, determine the specific order of the modes and realize accurate estimation of the underwater target distance by using all the modes.
Description
Technical Field
The invention belongs to the technical field of signal and information processing, and relates to an accurate underwater target distance estimation method based on simple wave mode group delay, which is suitable for sonar signal processing.
Background
Underwater target distance estimation has been a key problem in the field of hydroacoustics. According to the simple wave theory of underwater sound propagation, a sound source excites multi-order modes under water, sound pressure at a receiving point is formed by superposition of all the order modes, and distance information of the sound source is contained in a receiving signal.
Since the simple wave is a dispersion waveguide, each step Jian Zhengbo generates inter-mode dispersion and intra-mode dispersion in the propagation process, and the phenomenon can be observed on the time-frequency distribution diagram by representing the received signal, and the dispersion degree is directly related to the relative distance between the sound source and the receiving end. For the time-frequency distribution technology, reference may be made to Source depth estimation using modal decomposition and time-frequency representations, which relates to the theory of simple wave and the correlation theory of time-frequency analysis. Li Xiaoman and the like, in a shallow sea underwater sound source passive ranging method based on a single hydrophone, aiming at the passive ranging problem of a broadband pulse sound source in a shallow sea waveguide, the distance estimation of an underwater target is realized by utilizing the relation between the time delay difference of any two-order Jian Zhengbo mode reaching the hydrophone and the group velocity thereof on the basis of the group delay theory.
When the time-frequency processing is performed on the received signal, due to the correlation between the simple wave modal energy and the depth of the sound source and the hydrophone, the energy of a part of the sound source signal reaching the hydrophone is possibly close to zero, and the modal dispersion curve obtained through the time-frequency processing also has corresponding missing conditions, so that the modal order corresponding to the group velocity acquired through the acoustic calculation software cannot be judged, and the accuracy of calculating the underwater target distance is directly affected.
Disclosure of Invention
In order to solve the problems in the prior art, the invention provides an accurate underwater target distance estimation method based on a simple wave mode group delay.
The technical scheme of the invention is as follows:
and obtaining the time value of each order mode reaching the hydrophone through the time-frequency distribution of the received signal by utilizing the characteristic that the time delay difference of the adjacent two orders of modes of the time-frequency distribution of the simple wave reaches the hydrophone is an arithmetic series, comparing the time delay difference of the last order mode with the time delay difference of the first order mode with the arithmetic series summation formula calculation value, determining the corresponding condition of the time value and the mode order, and substituting each parameter into an underwater target distance calculation formula to realize the accurate estimation of the distance.
According to Jian Zhengbo theory, the group velocities of the modes of each order are different when the sound field propagates, and the arrival time t of the signal of the nth order propagating to the distance r is n (ω) satisfies the following relationship:
t n (ω)＝r/c gn (ω)
wherein c gn (omega) is the group velocity of the nth order mode at frequency omega, so the delay difference DeltaT between the nth order mode and the mth order mode mn (ω) can be expressed as:
c in the above gm (omega) is the group velocity of the m-th order mode at frequency omega, so when the signal frequency is omega 0 When using the m-th order and n-th order modal group velocity to calculate the underwater sound source distance r mn (ω 0 ) Can be expressed as:
obviously, this applies to the distance estimation of single frequency pulse sound sources, for possession of ω 1 ~ω 2 For the broadband signal of the frequency band, any two-order modes of each integer frequency point are selected to sequentially calculate in order to accurately estimate the distance, so that a simple wave with N-order modes can be obtainedThe theoretical formula of the estimated distance, i.e. the passive ranging of the underwater sound source, can be expressed as:
due to the series { DeltaT } consisting of time differences of all adjacent two-order modes at the same frequency 21 (ω),ΔT 32 (ω),···,ΔT N(N-1) (ω) } is an approximate arithmetic series, and in the experiment, M-order Jian Zhengbo modes are obtained after short-time Fourier transform, and ΔT is calculated 21 (ω)、ΔT 32 (ω)、···、ΔT M(M-1) (omega) the time delay difference U between the last-order mode and the first-order mode M Can be expressed as
U M ＝t M (ω)-t 1 (ω)
Wherein t is M 、t 1 The time values of the last-order mode and the first-order mode reaching the hydrophone are respectively calculated, and then a series { delta T is assumed 21 (ω),ΔT 32 (ω),···,ΔT M(M-1) (ω) } is an arithmetic progression, and the sum S of the terms is calculated using an arithmetic progression summation formula M 。
Will S M And U M And comparing, if the two values are approximate, judging that the mode is not missing at the moment, otherwise, judging that the mode missing condition exists in the calculation.
When judging that the modal deletion condition exists in the dispersion curve received by the hydrophone, sequentially checking continuous 3 items in the original arithmetic series by utilizing the characteristic that the subitems of the original arithmetic series are still arithmetic series until the S of the searched continuous 3 items 4 And U 4 The numerical value is approximate, at this time, the tolerance d of the subitem can be calculated, and then the time value t of reaching the hydrophone of each-order mode is calculated n And (omega) and the order n, and substituting each time value received by the hydrophone into the relational expression respectively to determine the corresponding modal order. Since this method requires the use of 3 consecutive delay differences that meet the conditions, it is required to use when the received dispersion curve contains consecutive 4-order modes of signal excitation.
The invention has the beneficial effects that: according to the invention, on the basis of calculating the distance of the underwater target by using the Jian Zhengbo group delay theory, whether the time-frequency distribution of the received signal has a modal missing condition is judged, and the distance of the underwater target can be accurately calculated under the modal missing condition.
Drawings
FIG. 1 is a flow chart of the present invention for accurately estimating the distance of an underwater target.
Figure 2 is a model of a shallow sea waveguide environment for use with the present invention.
FIG. 3 shows the loss of mode of the received signal dispersion curve; wherein (a) is the case of correspondence between the curve and the order when the mode absence is not considered, and (b) is the case of correspondence between the mode order and the dispersion curve after the mode absence is judged.
FIG. 4 is a graph comparing distance calculations when considering modal absence versus absence.
Detailed Description
The following describes specific embodiments of the present invention in detail with reference to the technical scheme and the accompanying drawings.
As shown in fig. 1, the invention provides an accurate estimation method for an underwater target distance based on a simple wave mode group delay, which specifically comprises the following steps:
step 1: and acquiring the time-frequency distribution of the single hydrophone received signal.
According to Jian Zhengbo theory, propagating through a marine waveguide at a hydrophone receives a signal expressed as:
wherein j is an imaginary number, r is a horizontal distance between the receiving point and the sound source, z is a depth of the receiving point, z s Is the sound source depth, ζ n (ω) is a horizontal component of the wave number of the sound source having a frequency ω; z is Z n (Z, ω) and Z n (z s ω) are the corresponding n-th order modal amplitudes at the receiving and transmitting points, ω 1 For minimum sound source frequency omega 2 For maximum sound source frequency, S (ω) is the generated signal spectrum.
And performing time-frequency processing on the received signal to obtain M dispersion curves of each order mode of the simple wave.
Step 2: calculate at frequency omega 0 The time delay difference delta T of reaching hydrophone of all adjacent two dispersion curves 21 (ω 0 )、ΔT 32 (ω 0 )、···、ΔT M(M-1) (ω 0 )。
Performing time-frequency analysis on the actually received time domain signal obtained in the step 1 to obtain frequency omega 0 The time value t of each simple wave dispersion curve reaching the hydrophone 1 (ω 0 )、t 2 (ω 0 )、···、t M (ω 0 ) The method comprises the steps of carrying out a first treatment on the surface of the Then, use the formula DeltaT M(M-1) (ω 0 )＝t M (ω 0 )-t M-1 (ω 0 ) Calculating the time delay difference delta T of all adjacent two dispersion curves reaching the hydrophone 21 (ω 0 ),ΔT 32 (ω 0 ),···,ΔT M(M-1) (ω 0 )。
Step 3: acquiring group velocity c of all N-order modes of the received signal at the moment through sound field calculation software g1 (ω 0 )、c g2 (ω 0 )、···、c gN (ω 0 )。
Step 4: respectively calculating the difference U between the time value of the last time-frequency curve and the time value of the first time-frequency curve reaching the hydrophone in the time-frequency distribution of the received signals M And a delay-difference sequence { DeltaT ] calculated using an arithmetic-sequence summation formula 21 (ω 0 ),ΔT 32 (ω 0 ),…,ΔT M(M-1) (ω 0 ) Sum S of M ：
U M ＝t M (ω 0 )-t 1 (ω 0 )
Step 5: calculation U M And S is equal to M Relative deviation p= |s between M -U M |/U M 。
Step 6: and (5) judging a termination condition. Checking factor for estrusAssignment, judgment->Whether or not it is.
Step 7: if the termination condition is satisfiedThen the sequence { DeltaT } 21 (ω 0 ),ΔT 32 (ω 0 ),…,ΔT M(M-1) (ω 0 ) The time-frequency distribution of the received signals does not have modal missing condition, and the step 8 is carried out; otherwise, it is concluded that the time-frequency distribution of the received signal has a modal loss, and the step 10 is performed.
Step 8: at omega 1 ～ω 2 Repeating the steps 2 and 3 in a range, and then calculating estimated distances r of different integer frequency points by using the m-th order and the n-th order modes mn (ω), where M is in the range {1,2, & gtM-1 } and n satisfies M < n.ltoreq.M.
Step 9: calculate all r of step 8 mn Mean value of (ω)
And r is the final target distance estimated value, and the algorithm is terminated.
Step 10: extracting successive 3 items { DeltaT of initial delay difference sequence 21 (ω 0 ),ΔT 32 (ω 0 ),ΔT 43 (ω 0 )}、{ΔT 32 (ω 0 ),ΔT 43 (ω 0 ),ΔT 54 (ω 0 )}、…、{ΔT (M-2)(M-3) (ω 0 ),ΔT (M-1)(M-2) (ω 0 ),ΔT M(M-1) (ω 0 ) M-3 new delay difference arrays are obtained.
Step 11: let x=4.
Step 12: calculate the delay difference array { DeltaT } (X-2)(X-3) (ω 0 ),ΔT (X-1)(X-2) (ω 0 ),ΔT X(X-1) (ω 0 ) U of } 4 、S 4 。
U 4 ＝t X (ω 0 )-t X-3 (ω 0 )
Step 13: calculation U 4 And S is equal to 4 Relative deviation p= |s between 4 -U 4 |/U 4 。
Step 14: and (5) judging a termination condition. JudgingWhether or not it is.
Step 15: if the termination condition is not satisfiedLet x=x+1, repeat steps 12 to 14. If the termination condition is satisfied, the searched { DeltaT is used (X-2)(X-3) (ω 0 ),ΔT (X-1)(X-2) (ω 0 ),ΔT X(X-1) (ω 0 ) Calculating a tolerance d satisfying the series of differences, and recording S obtained at this time 4 。
Step 16: will S 4 、d、ΔT X(X-1) (ω 0 ) Substituted into the following formula:
ΔT X(X-1) (ω 0 )＝a 1 +(x-1)d
obtaining a 1 The value of x is DeltaT X(X-1) (ω 0 ) For { DeltaT in absence of mode of received signal 21 (ω 0 ),ΔT 32 (ω 0 ),···,ΔT N(N-1) (ω 0 ) The x-th term of }, now used to calculate DeltaT X(X-1) (ω 0 ) T of (2) X (ω 0 ) And t X-1 (ω 0 ) In practice, the time t for the x+1st order and the x order modes of the signal to reach the hydrophone is respectively x+1 (ω 0 ) And t x (ω 0 )。
Step 17: will a 1 D and t x (ω 0 ) Substitution intoWherein C is a constant, and the time value t of reaching the hydrophone in the nth order mode of the simple wave is obtained n (ω 0 ) And the order n.
Step 18: time value t of initial dispersion curve 1 (ω 0 )、t 2 (ω 0 )、…、t M (ω 0 ) Substituted into t n (ω 0 ) In the relation between the order n, the corresponding real mode order is obtained, and the missing mode order can be determined at the moment.
Step 19: at omega 1 ～ω 2 Repeating the steps 2 and 3 in a range, and then calculating the estimated distance r of different integer frequency points by using the equation of the step 8 and using the mode of the mth order and the nth order mn (ω), where m is in the range {1,2, & gtN-1 } where N satisfies m < n.ltoreq.N, it should be noted that neither m nor N can take the missing mode order.
Step 20: assuming that the number of missing modes is k-th order, all r in step 19 are calculated mn Average value r of (ω):
the final target distance estimated value is obtained.
Claims (3)
1. The accurate underwater target distance estimation method based on the normal wave mode group delay is characterized by comprising the following steps of:
step 1: acquiring time-frequency distribution of single hydrophone received signals
According to Jian Zhengbo theory, propagating through a marine waveguide at a hydrophone receives a signal expressed as:
wherein j is an imaginary number, r is a horizontal distance between the receiving point and the sound source, z is a depth of the receiving point, z s Is the sound source depth, ζ n (ω) is a horizontal component of the wave number of the sound source having a frequency ω; z is Z n (Z, ω) and Z n (z s ω) are the corresponding n-th order modal amplitudes at the receiving and transmitting points, ω 1 For minimum sound source frequency omega 2 S (ω) is the occurrence signal spectrum for the maximum sound source frequency;
performing time-frequency processing on the received signal to obtain M dispersion curves of each order mode of the simple wave;
step 2: calculate at frequency omega 0 The time delay difference delta T of reaching hydrophone of all adjacent two dispersion curves 21 (ω 0 )、ΔT 32 (ω 0 )、···、ΔT M(M-1) (ω 0 )；
Step 3: acquiring group velocity c of all N-order modes of the received signal at the moment g1 (ω 0 )、c g2 (ω 0 )、···、c gN (ω 0 )；
Step 4: respectively calculating the time value of the last time-frequency curve and the first time-frequency curve of the time-frequency distribution of the received signal reaching the hydrophoneDifference U M And a delay-difference sequence { DeltaT ] calculated using an arithmetic-sequence summation formula 21 (ω 0 ),ΔT 32 (ω 0 ),…,ΔT M(M-1) (ω 0 ) Sum S of M ：
U M ＝t M (ω 0 )-t 1 (ω 0 )
Step 5: calculation U M And S is equal to M Relative deviation p= |s between M -U M |/U M ；
Step 6: termination condition judgment, checking factor according to conditionsAssignment, judgment->Whether or not to establish;
step 7: if the termination condition is satisfiedThen the sequence { DeltaT } 21 (ω 0 ),ΔT 32 (ω 0 ),…,ΔT M(M-1) (ω 0 ) The time-frequency distribution of the received signals does not have modal missing condition, and the step 8 is carried out; otherwise, the mode loss exists in the time-frequency distribution of the received signal, and the step 10 is carried out;
step 8: at omega 1 ~ω 2 Repeating the steps 2 and 3 in a range, and then calculating estimated distances r of different integer frequency points by using the m-th order and the n-th order modes mn (ω), where M is in the range {1,2, & gtM-1 } and n satisfies M < n.ltoreq.M:
step 9: calculate all r of step 8 mn Mean value of (ω)
The final target distance estimated value is obtained;
step 10: extracting successive 3 items { DeltaT of initial delay difference sequence 21 (ω 0 ),ΔT 32 (ω 0 ),ΔT 43 (ω 0 )}、{ΔT 32 (ω 0 ),ΔT 43 (ω 0 ),ΔT 54 (ω 0 )}、…、{ΔT (M-2)(M-3) (ω 0 ),ΔT (M-1)(M-2) (ω 0 ),ΔT M(M-1) (ω 0 ) Obtaining M-3 new delay difference sequences;
step 11: let x=4;
step 12: calculate the delay difference array { DeltaT } (X-2)(X-3) (ω 0 ),ΔT (X-1)(X-2) (ω 0 ),ΔT X(X-1) (ω 0 ) U of } 4 、S 4 ；
U 4 ＝t X (ω 0 )-t X-3 (ω 0 )
Step 13: calculation U 4 And S is equal to 4 Relative deviation p= |s between 4 -U 4 |/U 4 ；
Step 14: termination condition judgment, judgmentWhether or not to establish;
step 15: if the termination condition is not satisfiedLet x=x+1, repeat steps 12 to 14; if the termination condition is satisfied, the searched { DeltaT is used (X-2)(X-3) (ω 0 ),ΔT (X-1)(X-2) (ω 0 ),ΔT X(X-1) (ω 0 ) Calculating a tolerance d satisfying the series of differences, and recording S obtained at this time 4 ；
Step 16: will S 4 、d、ΔT X(X-1) (ω 0 ) Substituted into the following formula:
ΔT X(X-1) (ω 0 )＝a 1 +(x-1)d
obtaining a 1 The value of x is DeltaT X(X-1) (ω 0 ) For { DeltaT in absence of mode of received signal 21 (ω 0 ),ΔT 32 (ω 0 ),···,ΔT N(N-1) (ω 0 ) The x-th term of }, now used to calculate DeltaT X(X-1) (ω 0 ) T of (2) X (ω 0 ) And t X-1 (ω 0 ) In practice, the time t for the x+1st order and the x order modes of the signal to reach the hydrophone is respectively x+1 (ω 0 ) And t x (ω 0 )；
Step 17: will a 1 D and t x (ω 0 ) Substitution intoWherein C is a constant, when the n-th order mode of the simple wave reaches the hydrophoneIntermediate value t n (ω 0 ) A relation with the order n;
step 18: time value t of initial dispersion curve 1 (ω 0 )、t 2 (ω 0 )、…、t M (ω 0 ) Substituted into t n (ω 0 ) In the relation between the order n, the corresponding real mode orders are obtained, and the missing mode order can be determined at the moment;
step 19: at omega 1 ~ω 2 Repeating the steps 2 and 3 in a range, and then calculating the estimated distance r of different integer frequency points by using the equation of the step 8 and using the mode of the mth order and the nth order mn (ω), where m is in the range {1,2, & gtN-1 } and N satisfies m < n.ltoreq.N;
step 20: let the number of missing modes be k-th order, calculate all r in step 19 mn Average value r of (ω):
and r is the final target distance estimated value.
2. The accurate underwater target distance estimation method based on the reduced wave mode group delay according to claim 1, wherein the specific process of the step 2 is as follows: performing time-frequency analysis on the actually received time domain signal obtained in the step 1 to obtain frequency omega 0 The time value t of each simple wave dispersion curve reaching the hydrophone 1 (ω 0 )、t 2 (ω 0 )、···、t M (ω 0 ) The method comprises the steps of carrying out a first treatment on the surface of the Then, use the formula DeltaT M(M-1) (ω 0 )＝t M (ω 0 )-t M-1 (ω 0 ) Calculating the time delay difference delta T of all adjacent two dispersion curves reaching the hydrophone 21 (ω 0 ),ΔT 32 (ω 0 ),···,ΔT M(M-1) (ω 0 )。
3. The method for accurately estimating the distance between underwater targets based on the simple wave mode group delay according to claim 1 or 2, wherein in the step 19, neither m nor n can take the missing mode order.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311174613.2A CN117192556A (en) | 2023-09-12 | 2023-09-12 | Underwater target distance accurate estimation method based on simple wave mode group delay |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311174613.2A CN117192556A (en) | 2023-09-12 | 2023-09-12 | Underwater target distance accurate estimation method based on simple wave mode group delay |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN117192556A true CN117192556A (en) | 2023-12-08 |
Family
ID=88984604
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202311174613.2A Pending CN117192556A (en) | 2023-09-12 | 2023-09-12 | Underwater target distance accurate estimation method based on simple wave mode group delay |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN117192556A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117907998A (en) * | 2024-03-20 | 2024-04-19 | 西北工业大学青岛研究院 | Shallow sea broadband sound source ranging method, medium and system |
-
2023
- 2023-09-12 CN CN202311174613.2A patent/CN117192556A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117907998A (en) * | 2024-03-20 | 2024-04-19 | 西北工业大学青岛研究院 | Shallow sea broadband sound source ranging method, medium and system |
| CN117907998B (en) * | 2024-03-20 | 2024-05-28 | 西北工业大学青岛研究院 | Shallow sea broadband sound source ranging method, medium and system |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN117192556A (en) | Underwater target distance accurate estimation method based on simple wave mode group delay | |
| CN112415474B (en) | Linear difference frequency matching field method and medium for processing target acoustic passive positioning in water | |
| CN106019288A (en) | Normal wave modal frequency dispersion elimination transformation-based sound source distance and depth estimation method | |
| CN104168232B (en) | The assay method of multidiameter delay and Doppler frequency shift in a kind of underwater acoustic channel | |
| CN111563233B (en) | Passive inversion method for frequency dispersion characteristics of underwater acoustic signals based on nonlinear Bayesian theory | |
| CN108572349B (en) | Sound source depth setting method based on model calculation under deep sea environment | |
| CN117784250A (en) | Submarine acoustic parameter inversion method based on model independent element learning algorithm | |
| Guarino et al. | Bottom attenuation coefficient inversion based on the modal phase difference between pressure and vertical velocity from a single vector sensor | |
| CN110361690B (en) | Single-vector hydrophone direction finding method under condition of plane baffle | |
| CN111722178A (en) | Far-field narrow-band signal incoming wave direction estimation method based on numerical solution of directivity model | |
| CN110389007B (en) | Self-adaptive phase spectrum time delay estimation method | |
| CN113126029B (en) | Multi-sensor pulse sound source positioning method suitable for deep sea reliable acoustic path environment | |
| CN112684437B (en) | Passive ranging method based on time domain warping transformation | |
| JP2782180B2 (en) | Sound velocity measurement method in marine sediments | |
| KR101108260B1 (en) | apparatus and method for waveform inversion using multiple transform in Laplace-Fourier domain | |
| JP3511090B2 (en) | Wake locating method and device from vehicle noise | |
| CN113820717A (en) | Single-vector sensor passive ranging method based on warping transformation under negative gradient waveguide | |
| CN113093195A (en) | Underwater transient sound source depth distance estimation method based on time-frequency distribution correlation | |
| Hossain et al. | Error calculation in cross-correlation based population estimation technique of fish and mammals | |
| CN113611322A (en) | Method and device for removing reverberation of voice signal | |
| CN108459316B (en) | Echo signal parameter estimation method under multi-path channel | |
| CN113075645A (en) | Distorted formation line spectrum enhancement method based on principal component analysis-density clustering | |
| Harrison et al. | Robust source localization in an acoustic waveguide | |
| JPH1114443A (en) | Method for measuring characteristic value of mode | |
| Mashoshin | Study of the applicability conditions of the correlation function of a wideband multipath signal for estimating source coordinates |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |