CN107576989A - A kind of sea magetometer Magnetic field of ocean wave noise real-time suppression method - Google Patents
A kind of sea magetometer Magnetic field of ocean wave noise real-time suppression method Download PDFInfo
- Publication number
- CN107576989A CN107576989A CN201710608117.1A CN201710608117A CN107576989A CN 107576989 A CN107576989 A CN 107576989A CN 201710608117 A CN201710608117 A CN 201710608117A CN 107576989 A CN107576989 A CN 107576989A
- Authority
- CN
- China
- Prior art keywords
- sea
- noise
- magnetic field
- magnetometer
- value
- 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
Abstract
The invention discloses a kind of sea magetometer Magnetic field of ocean wave noise real-time suppression method, belong to marine geomagnetic field field of detecting.Comprise the following steps：Step 1：Start sea magetometer, read the output data of marine geomagnetic sensor as measurement；Step 2：Establish system state equation and measurement equation；Step 3：Estimate using improved Sage Husa adaptive Kalman filters the geomagnetic total field value at t_k moment at t_ (k 1) moment, and to system noise acoustic matrix Q and measure noise battle array R and be updated and correct；Step 4：Sea magetometer run time is M, if t_k=M, preserves data, sea magetometer completes measurement work；If t_k<M, then back substitution Q and R updated value, return to step three continue to estimate.The present invention solves perturbed problem when Magnetic field of ocean wave noise carries out high-precision ocean magnetic field detection to sea magetometer, also can guarantee that sea magetometer has higher detection accuracy under extreme sea condition.
Description
Technical Field
The invention belongs to the field of ocean geomagnetic field detection, and particularly relates to a real-time sea wave magnetic field noise suppression method for an ocean magnetometer.
Background
The ocean magnetometer is a main scientific instrument for realizing high-precision measurement of ocean geomagnetic fields, and is widely applied to the fields of ocean resource development, ocean military exploration, ocean engineering exploration and the like. The magnetometer is dragged by a ship to carry out mobile measurement, is flexible to use, is not influenced by a carrier magnetic field, and is one of main modes of ocean geomagnetic measurement. Through observation, the peak amplitude of the actual sea wave magnetic noise peak can reach several nT, and serious interference can be caused to the detection of a high-precision marine magnetometer. The current commonly adopted means is to select measurement under a good sea condition and reduce the influence of the sea wave magnetic field noise in a post data processing mode, but when special underwater magnetic detection is carried out, such as ocean engineering survey (sunken ship, airplane debris detection and the like) and military detection (anti-submarine, UXO detection and the like), weak magnetic anomaly of a target is required to be detected under an extreme sea condition, so that the interference of the sea wave magnetic field noise is inevitable. In addition, the above special detection usually requires the magnetometer to have the capability of real-time processing and correcting the magnetic data, so that the detection result can be preliminarily determined on site, and therefore, it is very necessary to realize real-time and adaptive suppression of the sea wave magnetic field noise in the special marine magnetic detection.
Zhu Xingle et al in the article "noise elimination of limited deep sea wave magnetic field in ship dynamic magnetic detection" (published in journal "university of naval engineering" in 2014, vol 26, no. 03), find that there is a difference between the frequency band of the sea wave magnetic field noise and the frequency band of the target through PM (Pierson Moskwitz) sea wave spectrum analysis, and therefore propose to use a Butterworth low-pass and band-pass filter to suppress the magnetic noise, but this method is only suitable for the situations of large detection target and slow dragging speed of marine magnetometer. Xiong Xiong in the article, "moving target aeromagnetic anomaly detection algorithm in sea wave magnetic noise background" (published in university of science and technology in china, "journal of 2015, volume 43, phase 03), it is proposed to use an LMS (Least Mean square) adaptive filtering algorithm to suppress the sea wave magnetic noise in aeromagnetic detection, but this method requires the prior measurement of the sea wave magnetic noise or the real-time measurement of the sea wave spectrum to compensate the influence of the noise. The actual sea waves are randomly distributed, so that the sea wave magnetic noise has time variability and randomness, and the frequency bands of the sea wave magnetic noise and the target magnetic anomaly cannot be absolutely separated. In summary, the frequency domain filtering method has a limited effect of suppressing the noise of the sea wave magnetic field.
Disclosure of Invention
The invention aims to provide a sea magnetometer sea wave magnetic field noise real-time suppression method based on an improved Sage-Husa adaptive Kalman filter, which can effectively suppress sea wave magnetic field noise in real time.
The purpose of the invention is realized by the following technical scheme:
a real-time sea wave magnetic field noise suppression method for an ocean magnetometer comprises the following steps:
(1) Starting the ocean magnetometer, and reading output data of the ocean geomagnetic sensor as quantity measurement;
(2) Establishing a system state equation and a measurement equation;
the system state equation is as follows:
X k ＝Φ k,k-1 X k-1 +W k-1
in the formula, the state variable X k Is the earth magnetic field state vector, phi k,k-1 Is t k-1 To t k One step transition matrix of time, W k-1 Is the system noise.
The measurement equation is as follows:
Z k ＝H k X k +V k
in the formula, Z k For measuring the vector, H k For measuring the matrix, V k To measure noise.
(3) At t k-1 Estimating t by using improved Sage-Husa adaptive Kalman filter at moment k Updating and correcting the system noise array Q and the measurement noise array R according to the geomagnetic total field value at the moment;
the step (3) specifically comprises the following steps:
(3.1) determining initial values of a system noise array Q and a measurement noise array R;
firstly, a group of pre-samples is carried out, the variance of the group of data is taken as the initial value of R, and n times of the value is taken as the initial value of Q.
(3.2) establishing a Weaver sea wave magnetic field noise model;
the Weaver sea wave magnetic field noise model can be expressed as:
when z is greater than 0, the reaction mixture is,
B y ＝0
when z is less than 0, the ratio of z,
B y ＝0
wherein A = amF (sinI + icosI cos θ), β =4 π σ g 2 /ω 3 ，m＝ω 2 The method comprises the following steps of determining the wave number of the sea wave, determining the amplitude of the sea wave, determining the depth of the sea water, determining the magnetic inclination angle, determining the included angle between the ocean current direction and the magnetic north pole, determining the angular frequency of the sea wave, determining the gravity acceleration and determining the conductivity of the sea water.
(3.3) carrying out improved Sage-Husa self-adaptive Kalman filter estimation, and updating and correcting a system noise array Q and a measurement noise array R;
the improved Sage-Husa adaptive Kalman filter iteration steps are as follows:
in the formula, d k ＝(1-b)/(1-b k )，0<b&1 is a forgetting factor, and the general value range is 0.95<b<0.995。Is composed ofOne-step state estimator of (2), P k|k-1 To estimate the covariance matrix of the errors, K k In order to be the gain of the filter,is the average value of the noise of the system,is an estimate of the noise of the system,in order to measure the mean value of the noise,to measure the estimate of noise, v k To update the information.
(4) The running time of the marine magnetometer is M, if t k If = M, the data is saved, and the ocean magnetometer finishes the measurement work; if t k &And (M), updating the values of Q and R, and returning to the third step to continue estimation.
In particular:
in the second step, t k-1 To t k One-step transition matrix value of time phi k,k-1 = I; the measurement matrix takes the value of H k ＝I。
The median value n =0.0025, which is an empirical value obtained from a plurality of experiments.
The forgetting factor b =0.98 in the step three is the best effect, and the value is an empirical value obtained by a plurality of experiments.
The invention has the beneficial effects that:
the sea wave magnetic field noise suppression method based on the improved Sage-Husa adaptive Kalman filter is innovatively used for suppressing sea wave magnetic field noise, is essentially linear unbiased minimum variance recursion estimation, is different from a common frequency domain filter, has the advantages of being high in instantaneity, low in dependence on prior information, high in self-adaptability and the like, solves the problem of disturbance of the sea wave magnetic field noise in high-precision sea magnetic field detection of a sea magnetometer, and can guarantee that the sea magnetometer has high detection precision even under extreme sea conditions.
Drawings
FIG. 1 is a flow chart of a method of the present invention;
FIG. 2 is a schematic diagram of a Weaver ocean wave magnetic field noise model;
FIG. 3 (a) is a diagram of the original measured signal in the present invention, (b) is a diagram of the noise suppression effect of the prior LMS adaptive filter, and (c) is a diagram of the noise suppression effect of the present invention;
FIG. 4 is a graph comparing the output residual of the LMS adaptive filter according to the present invention;
FIG. 5 is a power spectral density contrast diagram before and after suppression of noise in a sea wave magnetic field according to the present invention under a non-magnetic anomaly condition.
Detailed Description
The following further describes embodiments of the present invention with reference to the accompanying drawings:
the technical scheme adopted by the invention comprises the following steps:
the method comprises the following steps: starting the ocean magnetometer, and reading output data of the ocean geomagnetic sensor as quantity measurement;
step two: establishing a system state equation and a measurement equation;
the system state equation is as follows:
X k ＝Φ k,k-1 X k-1 +W k-1
in the formula, the state variable X k Is the earth magnetic field state vector, phi k,k-1 Is t k-1 To t k One step transition matrix of time, W k-1 Is system noise, where k,k-1 ＝I。
The measurement equation is as follows:
Z k ＝H k X k +V k
in the formula, Z k For measuring the vector, H k For measuring the matrix, V k For measuring noise, where H k ＝I。
In the marine magnetometer, the system noise W k Mainly FID (Free Induction Decay) signal phase noise and circuit noise of a frequency meter, wherein the phase noise is mainly generated by a receiving coil in a sensor and chemical shift in a solution; the circuit noise is zero-crossing voltage noise generated by an amplifying circuit and a power supply in the frequency meter. Phase circuit noise can cause frequency measurement errors in the frequency meter, resulting in indirect magnetic field noise. Since in a real marine environment there are no strong sources of electromagnetic interference as in terrestrial magnetic surveying, the measurement noise V is k Mainly the above-mentioned sea wave magnetic noise.
Step three: at t k-1 Estimating t by using improved Sage-Husa adaptive Kalman filter at moment k Updating and correcting the system noise array Q and the measurement noise array R according to the geomagnetic total field value at the moment;
step 3.1, determining initial values of a system noise array Q and a measurement noise array R;
firstly, a group of pre-samples is carried out, the variance of the group of data is taken as the initial value of R, and 0.0025 times of the value (the value is the empirical value obtained by a plurality of experiments) is taken as the initial value of Q.
Step 3.2, establishing a Weaver sea wave magnetic field noise model;
the Weaver sea wave magnetic field noise model is one of the sea wave induction magnetic field calculation models with higher precision at present, and the model assumes the motion of sea waves as the superposition of an infinite number of simple harmonic motions and can simultaneously calculate the magnetic fields above and below the sea level. The schematic diagram of the model is shown in FIG. 2, wherein a single simple harmonic is taken for explanation, and the positive direction of the x axis is along the propagation direction of sea waves; the y-axis is perpendicular to the x-axis; the positive direction of the z axis points to the sea bottom; when the sea surface is calm, taking z =0; i is a magnetic inclination angle (an included angle between a total geomagnetic field F and a geomagnetic north pole), and theta is an included angle between the ocean current direction and the geomagnetic north pole. The relation between the local sea wave magnetic field and the sea wave amplitude a, the sea water depth z and the sea wave angular frequency omega can be obtained through a Weaver sea wave magnetic field noise model.
The Weaver sea wave magnetic field noise model can be expressed as:
when z is greater than 0, the reaction mixture is,
B y ＝0
when z is less than 0, the ratio of z,
B y ＝0
wherein A = amF (sinI + icosI cos θ), β =4 π σ g 2 /ω 3 ，m＝ω 2 The method comprises the following steps of determining the wave number of the sea wave, determining the amplitude of the sea wave, determining the depth of the sea water, determining the magnetic inclination angle, determining the included angle between the ocean current direction and the magnetic north pole, determining the angular frequency of the sea wave, determining the gravity acceleration and determining the conductivity of the sea water.
Step 3.3, carrying out improved Sage-Husa adaptive Kalman filter estimation, and updating and correcting a system noise array Q and a measurement noise array R;
the invention adopts an improved Sage-Husa self-adaptive Kalman filter to inhibit the noise of the sea wave magnetic field, and can estimate and correct the initial value of a system noise variance array Q and a measurement noise variance array R in real time in a recursive manner while filtering the geomagnetic field.
The improved Sage-Husa adaptive Kalman filter iteration steps are as follows:
in the formula (d) k ＝(1-b)/(1-b k )，0<b<, 1 is forgetting factor, and the general value range is 0.95<b<0.995。Is composed ofOne-step state estimator of (2), P k|k-1 To estimate the covariance matrix of the errors, K k In order to be the gain of the filter,is the average value of the noise of the system,is an estimate of the noise of the system,in order to measure the mean value of the noise,to measure the estimate of noise, v k To update the information.
Step four: the running time of the marine magnetometer is M, if t k If not, storing the data, and finishing the measurement work by the marine magnetometer; if t k &And (M), updating the values of Q and R, and returning to the third step to continue estimation.
Example (b):
in order to verify the reasonability and feasibility of the method, a Matlab program is utilized to simulate the sea wave magnetic field noise real-time suppression method of the ocean magnetometer based on the improved Sage-Husa adaptive Kalman filter, and in order to realize comparative analysis, the noise suppression effect of the method is compared with the noise suppression effect of an LMS adaptive filter, which is a typical representative in a frequency domain filtering method.
Considering various situations comprehensively, taking a certain sea area in the east China sea as an example, the set initial conditions are as follows:
the total geomagnetic field F =47300nT, the wave period changes within 0.5S-1S, the wave amplitude range is 0m-1m, I =45 °, sigma =4.2S/m, and theta =0 °; the sea wave is assumed to be the superposition of 30 simple harmonic motions with different frequencies and different amplitudes under the condition.
The sea wave magnetic field noise generated under the sea condition is used as measuring noise; and (3) taking the magnetic anomaly generated by the small iron blocks placed in the depth of 1m in the water tank as a target signal, taking the output read from the magnetometer sensor at the moment as the effective value of the total geomagnetic field, and superposing to obtain the measurement Z.
After the preparation of starting and preheating the ocean magnetometer is completed, pre-sampling is carried out in a water area which is 5m away from the small iron block, the variance of pre-sampling data is taken as an initial value of a measurement noise variance array R, and 0.0025 time of the value is taken as an initial value of a system noise variance array Q.
And (3) simulation results:
fig. 3 (a) shows a raw measurement signal diagram, (b) shows a noise suppression effect diagram of the existing LMS adaptive filter, and (c) shows a noise suppression effect diagram of the improved Sage-Husa adaptive kalman filter of the present invention, which is shown by comparison results: although the LMS adaptive filter artificially gives the optimal prior parameters and has a certain noise suppression effect, the improved Sage-Husa adaptive Kalman filter not only realizes the self-adaptation of a measurement noise variance array R and a system noise variance array Q, but also has a more remarkable noise suppression effect.
Fig. 4 is a graph comparing the residual error (the modulus of the difference between the output of the filter and the ideal signal) of the present invention method and the conventional LMS adaptive filter. The comparison result shows that: the output of the improved Sage-Husa adaptive Kalman filter is closer to an ideal signal, and the noise suppression effect of the improved Sage-Husa adaptive Kalman filter is obviously better than that of an LMS adaptive filter in a frequency domain filtering method.
FIG. 5 is a graph showing the power spectral density contrast before and after the suppression of the noise of the sea wave magnetic field in the absence of magnetic anomaly. As can be seen, the improved Sage-Husa adaptive Kalman filteringAfter being processed by the processor, the power spectral density of the sea wave magnetic field noise is determined byDown toQuantitatively, the noise of the sea wave magnetic field is effectively suppressed.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (6)
1. A real-time sea magnetometer sea wave magnetic field noise suppression method is characterized by comprising the following steps:
(1) Starting the ocean magnetometer, and reading output data of the ocean geomagnetic sensor as quantity measurement;
(2) Establishing a system state equation and a measurement equation;
(3) At t k-1 Estimating t by using improved Sage-Husa adaptive Kalman filter at moment k Updating and correcting the system noise array Q and the measurement noise array R according to the geomagnetic total field value at the moment;
(4) The running time of the marine magnetometer is M, if t k If not, storing the data, and finishing the measurement work by the marine magnetometer; if t k &And (M), updating the values of Q and R, and returning to the third step to continue estimation.
2. The method for suppressing sea magnetometer and sea magnetometer sea wave magnetic field noise in real time according to claim 1, wherein in the step (2):
the system state equation is:
X k ＝Φ k,k-1 X k-1 +W k-1
in the formula, the state variable X k Is the earth magnetic field state vector, phi k,k-1 Is t k-1 To t k One step transition matrix of time, W k-1 Is the system noise;
the measurement equation is as follows:
Z k ＝H k X k +V k
in the formula, Z k For measuring the vector, H k For measuring the matrix, V k To measure noise.
3. The method for suppressing noise in real time from sea magnetometer and sea wave magnetic field according to claim 1,2, wherein in step (2), t is k-1 To t k One-step transition matrix value of time phi k,k-1 = I; the measurement matrix takes the value of H k ＝I。
4. The method for suppressing the sea magnetometer and the sea wave magnetic field noise in real time according to claim 1, wherein the step (3) specifically comprises the following steps:
(3.1) determining initial values of a system noise array Q and a measurement noise array R:
firstly, a group of pre-sampling is carried out, the variance of the group of data is taken as the initial value of R, and n times of the value is taken as the initial value of Q;
(3.2) establishing a Weaver sea wave magnetic field noise model:
when z is greater than 0, the reaction mixture is,
B y ＝0
when z is less than 0, the ratio of z,
B y ＝0
wherein A = amF (sinI + icosI cos θ), β =4 π σ g 2 /ω 3 ，m＝ω 2 The method comprises the following steps that the angular wave number is/g, the sea wave amplitude is a, the sea water depth is z, the magnetic inclination angle is I, the included angle between the sea current direction and the geomagnetic north pole is theta, the sea wave angular frequency is omega, the gravity acceleration is g, and the sea water conductivity is sigma;
(3.3) carrying out improved Sage-Husa adaptive Kalman filter estimation, and updating and correcting a system noise array Q and a measurement noise array R:
the improved Sage-Husa adaptive Kalman filter iteration steps are as follows:
in the formula (d) k ＝(1-b)/(1-b k )，0<b<, 1 is forgetting factor, and the general value range is 0.95<b<0.995，Is composed ofOne-step state estimator of (1), P k|k-1 To estimate the covariance matrix of the errors, K k In order to be the gain of the filter,is the average value of the noise of the system,is an estimate of the noise of the system,in order to measure the mean value of the noise,to measure the estimate of noise, v k To updateAnd (4) information.
5. The method for suppressing noise in real time in a sea magnetometer and a sea magnetometer of claim 1,4 is characterized in that in step (3), the multiple value n =0.0025, which is an empirical value obtained through multiple experiments.
6. A method for suppressing sea magnetometer and sea magnetometer sea wave magnetic field noise in real time according to claim 1,4 wherein step (3) is performed with the best effect when forgetting factor b =0.98, and the value is an empirical value obtained by a plurality of experiments.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710608117.1A CN107576989A (en) | 2017-07-24 | 2017-07-24 | A kind of sea magetometer Magnetic field of ocean wave noise real-time suppression method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710608117.1A CN107576989A (en) | 2017-07-24 | 2017-07-24 | A kind of sea magetometer Magnetic field of ocean wave noise real-time suppression method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN107576989A true CN107576989A (en) | 2018-01-12 |
Family
ID=61034018
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201710608117.1A Pending CN107576989A (en) | 2017-07-24 | 2017-07-24 | A kind of sea magetometer Magnetic field of ocean wave noise real-time suppression method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN107576989A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109783875A (en) * | 2018-12-19 | 2019-05-21 | 东南大学 | A kind of self iteration update optimization algorithm of marine gravity data |
| CN111722302A (en) * | 2020-06-29 | 2020-09-29 | 宁夏大学 | Vertical acceleration correction method for AUV (autonomous Underwater vehicle) gravimeter |
| CN111856590A (en) * | 2020-08-05 | 2020-10-30 | 中国海洋大学 | Sea wave magnetic interference suppression method for ocean magnetotelluric detection |
| CN112834577A (en) * | 2019-11-22 | 2021-05-25 | 中国船舶重工集团公司第七六研究所 | Correlation method for judging marine environment magnetic field and seawater conductivity |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103852796A (en) * | 2014-02-18 | 2014-06-11 | 中国人民解放军92859部队 | Method for measuring magnetic anomaly intensity of underwater small targets |
| CN205665416U (en) * | 2016-05-10 | 2016-10-26 | 宁波冶金勘察设计研究股份有限公司 | Sea magnetometer |
-
2017
- 2017-07-24 CN CN201710608117.1A patent/CN107576989A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103852796A (en) * | 2014-02-18 | 2014-06-11 | 中国人民解放军92859部队 | Method for measuring magnetic anomaly intensity of underwater small targets |
| CN205665416U (en) * | 2016-05-10 | 2016-10-26 | 宁波冶金勘察设计研究股份有限公司 | Sea magnetometer |
Non-Patent Citations (2)
| Title |
|---|
| J.T.WEAVER: "Magnetic Variations Associated with Ocean Waves and Swell", 《JOURNAL OF GEOPHYSICAL RESEARCH》 * |
| 葛健 等: "基于改进的Sage-Husa自适应Kalman滤波器的拖曳式Overhauser海洋磁场传感器海浪磁场噪声实时抑制方法", 《HTTP://MAX.BOOK118.COM》 * |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109783875A (en) * | 2018-12-19 | 2019-05-21 | 东南大学 | A kind of self iteration update optimization algorithm of marine gravity data |
| CN112834577A (en) * | 2019-11-22 | 2021-05-25 | 中国船舶重工集团公司第七六研究所 | Correlation method for judging marine environment magnetic field and seawater conductivity |
| CN112834577B (en) * | 2019-11-22 | 2022-12-02 | 中国船舶重工集团公司第七六研究所 | Correlation method for judging marine environment magnetic field and seawater conductivity |
| CN111722302A (en) * | 2020-06-29 | 2020-09-29 | 宁夏大学 | Vertical acceleration correction method for AUV (autonomous Underwater vehicle) gravimeter |
| CN111856590A (en) * | 2020-08-05 | 2020-10-30 | 中国海洋大学 | Sea wave magnetic interference suppression method for ocean magnetotelluric detection |
| CN111856590B (en) * | 2020-08-05 | 2023-03-17 | 中国海洋大学 | Sea wave magnetic interference suppression method for ocean magnetotelluric detection |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN107576989A (en) | A kind of sea magetometer Magnetic field of ocean wave noise real-time suppression method | |
| CN105676181B (en) | Underwater movement objective Extended Kalman filter tracking based on distributed sensor energy ratio | |
| CN111123173B (en) | Deep and far sea magnetic force abnormity detection system and detection method based on buoy | |
| CN111399066B (en) | Method for processing scalar magnetic anomaly gradient signal based on orthogonal basis function | |
| CN110855374A (en) | Underwater sound target radiation noise modulation feature extraction method | |
| CN112729291A (en) | SINS/DVL ocean current velocity estimation method for deep-submergence long-endurance submersible | |
| CN110749891A (en) | Self-adaptive underwater single beacon positioning method capable of estimating unknown effective sound velocity | |
| CN112285767A (en) | Ocean bottom seismograph four-component ocean surface wave multi-order frequency dispersion energy imaging device and method | |
| Ge et al. | Towed Overhauser marine magnetometer for weak magnetic anomaly detection in severe ocean conditions | |
| CN112649882A (en) | Low-frequency magnetic signal enhancement method and aviation magnetic measurement system using same | |
| Yu et al. | Ship target tracking using underwater electric field | |
| Gong et al. | A vibration signal denoising method of marine atomic gravimeter based on improved variational mode decomposition | |
| CN112285787B (en) | System and method for detecting extremely low frequency magnetic field of underwater target from air | |
| CN104618033A (en) | Multi-layer self-adapting morphological filtering gravity signal noise inhibition method | |
| Hao et al. | Research on optimized m-estimate arithmetic in ins/usbl integrated navigation system | |
| Walker | Magnetic signature mapping of a moving ship using a fleet of autonomous underwater vehicles | |
| Epishkin et al. | Technology of marine magnetotelluric sounding in transition zone | |
| JPH10160746A (en) | Measuring apparatus for tidal flow | |
| CN112578470B (en) | Product function-based ocean controllable source electromagnetic and magnetotelluric joint inversion method | |
| Zhang et al. | Compensation of UUV magnetic field interference based on ridge estimation | |
| CN117331132A (en) | Target electric field detection noise suppression method and device based on ocean environment power | |
| Nieves et al. | Optimizing Correlations of Magnetic and Hydrodynamics Signatures | |
| CN111948714B (en) | Noise reduction method and noise reduction device for uplink wave in submarine node seismic data | |
| CN116384037A (en) | Modeling method for shaking noise of magnetic detection buoy platform | |
| Nieves et al. | Isolating the magnetic signature of internal waves |
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 | ||
| RJ01 | Rejection of invention patent application after publication | ||
| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20180112 |