CN110048795A - A kind of method and device of seismic detector acquisition data clock - Google Patents
A kind of method and device of seismic detector acquisition data clock Download PDFInfo
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- CN110048795A CN110048795A CN201910230028.7A CN201910230028A CN110048795A CN 110048795 A CN110048795 A CN 110048795A CN 201910230028 A CN201910230028 A CN 201910230028A CN 110048795 A CN110048795 A CN 110048795A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
- G01V1/00—Seismology; Seismic or acoustic prospecting or detecting
- G01V1/24—Recording seismic data
- G01V1/242—Seismographs
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
- G01V1/00—Seismology; Seismic or acoustic prospecting or detecting
- G01V1/24—Recording seismic data
- G01V1/247—Digital recording of seismic data, e.g. in acquisition units or nodes
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
- G01V1/00—Seismology; Seismic or acoustic prospecting or detecting
- G01V1/38—Seismology; Seismic or acoustic prospecting or detecting specially adapted for water-covered areas
- G01V1/3808—Seismic data acquisition, e.g. survey design
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04J—MULTIPLEX COMMUNICATION
- H04J3/00—Time-division multiplex systems
- H04J3/02—Details
- H04J3/06—Synchronising arrangements
- H04J3/0635—Clock or time synchronisation in a network
- H04J3/0638—Clock or time synchronisation among nodes; Internode synchronisation
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04J—MULTIPLEX COMMUNICATION
- H04J3/00—Time-division multiplex systems
- H04J3/02—Details
- H04J3/06—Synchronising arrangements
- H04J3/0635—Clock or time synchronisation in a network
- H04J3/0638—Clock or time synchronisation among nodes; Internode synchronisation
- H04J3/0644—External master-clock
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Abstract
The method and device of seismic detector acquisition data clock provided by the invention, bandpass filtering is carried out to the underwater sound timing signal of acquisition, filtered underwater sound timing signal is obtained, the optimal rotation angle that Fourier Transform of Fractional Order calculates underwater sound timing signal is carried out to filtered underwater sound timing signal；Filtered underwater sound timing signal is intercepted, each underwater sound timing signal then peak swing is obtained, determines seismic detector clock skew inside in the moment of the interval using per underwater sound timing signal peak swing deviation twice；Resampling correction is carried out to acquisition data according to clock skew inside, obtain clock synchronization data, the present invention is by the linear FM signal with big time width bandwidth product, the influence that the complexity and multipath effect of marine environment are overcome in underwater sound timing signal is applied as a kind of pulse compression signal, pass through the transmitting linear FM signal of multiple timing, to inhibit to the interference of single frequency point, it ensure that signal has better signal-to-noise ratio in remote situation.
Description
Technical field
The present invention relates to submarine geophysics detection technology field, in particular to a kind of side of seismic detector acquisition data clock
Method and device.
Background technique
Submarine geophysics detection equipment, especially submarine seismograph (Ocean Bottom Seismometer, referred to as
OBS), submarine earthquake acquisition node (OBN) operation at sea generally requires more even up to a hundred instruments operations simultaneously, and every
Instrument be all it is independent be acquired operation, since electromagnetic wave is decayed rapidly in the seawater, undersea device can not receive GPS clock
Signal, habitata equipment can only carry out operating to clock for GPS before operation on the sea before dispensing and after recycling, after instrument is plunged into the commercial sea
Clock inside relying on always carries out timing and acquires data, therefore internal clock accuracy becomes influence acquisition data accuracy
Key condition, FairField company in the U.S. uses every OBN to be equipped with high-precision atomic clock as internal clocking with reality at present
The high precision clock synchronous acquisition of existing multiple devices does industry, but high-precision atomic clock power consumption is much higher than conventional crystal oscillator, and every OBN is equal
Will lead to equipment using atomic clock stays the extra large activity duration to have a greatly reduced quality, and the high engineering that is unfavorable for of atomic clock expense is applied.
Patent ZL201611213350.1 propose a kind of submarine geophysics exploration instrument clock synchronization device and
Method, using underwater sound emitter transmitting high accurate clock signal as habitata instrument clock synchronizing method, in the underwater sound
Emitter and habitata instrument launch before can by the PPS signal of GPS in emitter atomic clock and seabed visit
The clock for surveying instrument internal is tamed and is corrected, and the reference clock for forming instrument operation makes it guarantee both sides' initial time one
It causes, underwater sound emitter emits the underwater sound synchronization signal of regular length in seabed after dispensing, and habitata instrument will collect this
Signal preserves, and carries out Analysis of Magnitude-Frequency Characteristic by the underwater acoustic pulse signal of the 12kHZ to transmitting using host computer after recycling,
By judging that amplitude maximum determines that signal then obtains the laggard row clock correction of appliance time deviation.But in practical applications
On the one hand single since there is underwater sound signal strong time-varying, the complexity of space-variant and marine environment and multipath effect etc. to influence
Frequency signal is often submerged in reverberation and noise as distance increases weak target signal, and doppler shift effect is obvious,
The disadvantages of signal signal-to-noise ratio is low, operating distance is short.Traditional Discrete Fourier Transform is utilized in another aspect System for Underwater Acoustic Signals Recognition
(DiscreteFourier Transform, DFT) analysis method can only provide signal it is transformed after in single domain (time domain or frequency
Domain) in global feature information be adapted only to analyze deterministic signal and steady letter there is no the whole useful signals for including signal
Number.And to the more complex environments of Yu Haiyang, single frequency point signal is often by noise jamming, and using which, it is difficult to extract to accurately
Signal then information.
Summary of the invention
Have in view of that, it is necessary in view of the defects existing in the prior art, the anti-interference high-precision seismic detector of one kind be provided and adopted
Collect the method and device of data clock precision.
To achieve the above object, the present invention adopts the following technical solutions:
On the one hand, the present invention provides a kind of method of seismic detector acquisition data clock, include the following steps:
Obtain underwater sound timing signal；
Bandpass filtering is carried out to the underwater sound timing signal, obtains filtered underwater sound timing signal；
The optimal rotation that Fourier Transform of Fractional Order calculates underwater sound timing signal is carried out to filtered underwater sound timing signal
Angle；
Filtered underwater sound timing signal is intercepted, successively carries out fractional order Fourier using the optimal rotation angle
Transformation, obtains each underwater sound timing signal then peak swing；
Seismic detector internal clocking in the moment of the interval is determined using per the underwater sound timing signal peak swing deviation described twice
Deviation；
Resampling correction is carried out to acquisition data according to the clock skew inside, obtains clock synchronization data.
In some preferred embodiments, it in the step of obtaining underwater sound timing signal, specifically includes:
Underwater sound emitter is set in target area；
Seismic detector is laid at interval in the target area, according to the number that the underwater sound emitter emits, is successively marked
1,2,3 are denoted as ...；
The underwater sound timing signal that the seismic detector records is denoted as S (i, j), wherein i indicates seismographic number, and j is indicated
The number of collected underwater sound timing signal.
In some preferred embodiments, bandpass filtering is being carried out to the underwater sound timing signal, is obtaining filtered water
In the step of sound timing signal, specifically include the following steps:
Discrete Fourier transform is carried out to the underwater sound timing signal S (i, j)；
Using following formula, acquisition signal is changed into frequency domain, the formula by time-domain are as follows:
In formula, X (k) indicate DFT transform after from time-domain to frequency domain as a result, x (n) indicate underwater sound timing signal when
Between sequence, k and n indicate identical sampling number；
According to the effective band range f of linear frequency modulation underwater sound timing signal1-f2, by X (k) midband range f1-f2In addition
Data set 0 after, to X (k) data carry out discrete fourier change inverse transformation, obtain filtered underwater sound timing signal Sbf(i,
j)。
In some preferred embodiments, Fourier Transform of Fractional Order calculating is being carried out to filtered underwater sound timing signal
In the step of optimal rotation angle of underwater sound timing signal, specifically include the following steps:
Choose underwater sound timing signal S after filteringbfAny primary underwater sound timing signal in (i, j), using following formula into
The variation of row fractional order Fourier, the formula are as follows:
In formula, n is integer, FpFor the operator notation of Fourier Transform of Fractional Order, P is the rank of Fourier Transform of Fractional Order, α
=p pi/2,0 < | p | 2,0 < of < | α | < π；
Construct following formula:
In formula, fsFor the sample frequency of seismic detector underwater sound timing signal, N is sampling number, and K is the tune of linear FM signal
Frequency；
With a0Centered on, using step-length as Δ d in the range of ± d, to filtered underwater sound timing signal Sbf(i, j) iteration
Calculate the amplitude peak of Fourier Transform of Fractional Order under different rank；
By judging that signal convergence in the domain U is best, peak swing peak value highest obtains the underwater sound timing signal and is dividing
Corresponding optimal rotation angle a under number rank Fourier transformationopt。
In some preferred embodiments, between using being somebody's turn to do per the underwater sound timing signal peak swing deviation twice is determining
In every the seismic detector clock skew inside in the moment the step of, specifically:
Utilize the collected underwater sound timing signal of seismic detector then peak swing Fp(i), reciprocal fraction rank Fourier transformation
The sampling point number for converting the lower domain U is u (i), and note collects underwater sound timing signal peak swing F for the first timep(0) corresponding sampled point
Number u (0) is zero moment；
By following formula, the arrival time difference for calculating underwater sound timing signal is
In formula, Δ t (i) is then deviation of the seismic detector in i underwater sound timing signal, fsFor seismic detector underwater sound timing signal
Sample frequency, aoptFor the optimal rotation angle under Fourier Transform of Fractional Order.
On the other hand, the present invention also provides a kind of devices of seismic detector acquisition data clock, comprising:
Signal acquiring unit, for obtaining underwater sound timing signal；
Filter unit obtains filtered underwater sound timing signal for carrying out bandpass filtering to the underwater sound timing signal；
Rotation angle computing unit calculates the underwater sound for carrying out Fourier Transform of Fractional Order to filtered underwater sound timing signal
The optimal rotation angle of timing signal；
Magnitude determinations unit, for being intercepted to filtered underwater sound timing signal, using the optimal rotation angle according to
Secondary carry out Fourier Transform of Fractional Order obtains each underwater sound timing signal then peak swing；
Clock jitter unit, for determining the interval moment using per the underwater sound timing signal peak swing deviation described twice
Interior seismic detector clock skew inside；
Clock synchronization data unit, for carrying out resampling correction to acquisition data according to the clock skew inside,
Obtain clock synchronization data.
In some preferred embodiments, the signal acquiring unit includes: the underwater sound transmitting being arranged in target area
Device, seismic detector is laid at interval in the target area, according to the number that the underwater sound emitter emits, is successively labeled as
1,2,3 ...；
The underwater sound timing signal of the seismic detector record is denoted as S (i, j), wherein i indicates seismographic number, and j expression is adopted
The number of the underwater sound timing signal collected.
In some preferred embodiments, filter unit includes:
Discrete Fourier transform module, for carrying out discrete Fourier transform to the underwater sound timing signal S (i, j)；
Acquisition signal is changed into frequency domain, the public affairs by time-domain for using following formula by frequency domain conversion module
Formula are as follows:
In formula, X (k) indicate DFT transform after from time-domain to frequency domain as a result, x (n) indicate underwater sound timing signal when
Between sequence, k and n indicate identical sampling number；
First computing module, for the effective band range f according to linear frequency modulation underwater sound timing signal1-f2, will be in X (k)
Frequency range f1-f2After data in addition set 0, discrete fourier is carried out to X (k) data and changes inverse transformation, obtains filtered water
Sound timing signal Sbf(i, j).
In some preferred embodiments, rotation angle computing unit includes:
Fractional order Fourier changes module, for underwater sound timing signal S after selection filteringbfAny primary water in (i, j)
Sound timing signal carries out fractional order Fourier variation, the formula using following formula are as follows:
In formula, n is integer, FpFor the operator notation of Fourier Transform of Fractional Order, P is the rank of Fourier Transform of Fractional Order, α
=p pi/2,0 < | p | 2,0 < of < | α | < π；
Module is constructed, for constructing following formula:
In formula, fsFor the sample frequency of seismic detector underwater sound timing signal, N is sampling number, and K is the tune of linear FM signal
Frequency；
Second computing module, for a0Centered on, using step-length as Δ d in the range of ± d, when to the filtered underwater sound
Mark signal Sbf(i, j) iterates to calculate the amplitude peak of Fourier Transform of Fractional Order under different rank；
Rotation angle judgment module, for by judging that signal convergence in the domain U is best, peak swing peak value highest to be obtained
The underwater sound timing signal corresponding optimal rotation angle a under Fourier Transform of Fractional Orderopt。
In some preferred embodiments, the clock jitter unit includes:
Zero moment obtains module, utilizes the collected underwater sound timing signal of seismic detector then peak swing Fp(i), corresponding point
The sampling point number that number rank Fourier transformation converts the lower domain U is u (i), and note collects underwater sound timing signal peak swing F for the first timep
(0) corresponding sampling point number u (0) is zero moment；
Third computing module, for being by the arrival time difference of following formula, calculating underwater sound timing signal
In formula, Δ t (i) is then deviation of the seismic detector in i underwater sound timing signal, fsFor seismic detector underwater sound timing signal
Sample frequency, aoptFor the optimal rotation angle under Fourier Transform of Fractional Order.
The present invention by adopting the above technical scheme the advantages of be:
The method and device of seismic detector provided by the invention acquisition data clock, to the underwater sound timing signal of acquisition into
Row bandpass filtering obtains filtered underwater sound timing signal, carries out fractional order Fourier change to filtered underwater sound timing signal
Change the optimal rotation angle for calculating underwater sound timing signal；Filtered underwater sound timing signal is intercepted, the optimal rotation is utilized
Corner successively carries out Fourier Transform of Fractional Order, obtains each underwater sound timing signal then peak swing, using per described twice
Underwater sound timing signal peak swing deviation determines seismic detector clock skew inside in the moment of the interval；According to the internal clocking
Deviation carries out resampling correction to acquisition data, obtains clock synchronization data, and seismic detector provided by the invention acquires data clock
Method and dress the linear FM signal with big time width bandwidth product is applied as a kind of pulse compression signal in the underwater sound
The influence that the complexity and multipath effect of marine environment are overcome in timing signal is believed by the transmitting linear frequency modulation of multiple timing
Number, so that the interference to single frequency point carries out certain inhibiting effect, it is better to ensure that signal has in remote situation
Signal-to-noise ratio.
In addition, the method and device of seismic detector acquisition data clock provided by the invention, after recycling habitata instrument,
Has the characteristics that energy accumulating to collected underwater sound timing signal to LFM signal using Fourier Transform of Fractional Order (FRFT)
Progress quickly then identify, can be good at inhibition time frequency analysis when cross term and reverberation, noise background under it is existing more
Pu Le influences, and obtains accurate underwater sound markers then, and it is inclined to obtain the clock inside the acquisition of habitata instrument by calculating
Difference, which have calculation method precision high, and calculation amount is suitable with FFT, and the clock jitter after correction does not increase with acquisition duration
And the features such as accumulating.
Detailed description of the invention
In order to more clearly explain the embodiment of the invention or the technical proposal in the existing technology, to embodiment or will show below
There is attached drawing needed in technical description to be briefly described, it should be apparent that, the accompanying drawings in the following description is only this
Some embodiments of invention for those of ordinary skill in the art without creative efforts, can be with
Other attached drawings are obtained according to these attached drawings.
Fig. 1 is the step flow chart for the method that the seismic detector that the embodiment of the present invention 1 provides acquires data clock.
Fig. 2 is the structural schematic diagram for the device that the seismic detector that the embodiment of the present invention 2 provides acquires data clock.
Fig. 3 is the work layout drawing that the embodiment of the present invention 1 or embodiment 2 provide.
Fig. 4 is the underwater sound signal test chart that the simulation that the embodiment of the present invention 1 or embodiment 2 provide receives.
Specific embodiment
Following will be combined with the drawings in the embodiments of the present invention, and technical solution in the embodiment of the present invention carries out clear, complete
Site preparation description, it is clear that described embodiments are only a part of the embodiments of the present invention, instead of all the embodiments.It is based on
Embodiment in the present invention, it is obtained by those of ordinary skill in the art without making creative efforts all other
Embodiment shall fall within the protection scope of the present invention.
Embodiment 1
Referring to Fig. 1, to acquire the step flow chart of the method for data clock the present invention provides a kind of seismic detector, in order to
Convenient for explanation, only parts related to embodiments of the present invention are shown, and details are as follows.
In Fig. 1, the method for seismic detector acquisition data clock provided by the invention includes the following steps:
Step S110: underwater sound timing signal is obtained.
In some preferred embodiments, it in the step of obtaining underwater sound timing signal, specifically includes:
Step S111: underwater sound emitter is set in target area；Usually apart from the farthest transmission range 1500m of seismic detector
In range；
Step S112: seismic detector is laid at interval in the target area, according to time of underwater sound emitter transmitting
Number is successively labeled as 1,2,3 ...；
Step S113: the underwater sound timing signal that the seismic detector records is denoted as S (i, j), wherein i indicates seismographic
Number, j indicate the number of collected underwater sound timing signal.
Step S120: bandpass filtering is carried out to the underwater sound timing signal, obtains filtered underwater sound timing signal.
In some preferred embodiments, bandpass filtering is carried out to the underwater sound timing signal, obtains the filtered underwater sound
Timing signal, specifically include the following steps:
Step S121: discrete Fourier transform is carried out to the underwater sound timing signal S (i, j)；
Step S122: using following formula, and acquisition signal is changed into frequency domain, the formula by time-domain are as follows:
In formula, X (k) indicate DFT transform after from time-domain to frequency domain as a result, x (n) indicate underwater sound timing signal when
Between sequence, k and n indicate identical sampling number；
Step S123: according to the effective band range f of linear frequency modulation underwater sound timing signal1-f2, by X (k) midband range
f1-f2After data in addition set 0, discrete fourier is carried out to X (k) data and changes inverse transformation, obtains filtered underwater sound markers letter
Number Sbf(i, j).
Step S130: Fourier Transform of Fractional Order is carried out to filtered underwater sound timing signal and calculates underwater sound timing signal
Optimal rotation angle；
In some preferred embodiments, Fourier Transform of Fractional Order calculating is being carried out to filtered underwater sound timing signal
In the step of optimal rotation angle of underwater sound timing signal, specifically include the following steps:
Step S131: underwater sound timing signal S after filtering is chosenbfAny primary underwater sound timing signal in (i, j), under
It states formula and carries out fractional order Fourier variation, the formula are as follows:
In formula, n is integer, FpFor the operator notation of Fourier Transform of Fractional Order, P is the rank of Fourier Transform of Fractional Order, α
=p pi/2,0 < | p | 2,0 < of < | α | < π；
Step S132: following formula are constructed:
In formula, fsFor the sample frequency of seismic detector underwater sound timing signal, N is sampling number, and K is the tune of linear FM signal
Frequency；
Step S133: with a0Centered on, using step-length as Δ d in the range of ± d, to filtered underwater sound timing signal Sbf
(i, j) iterates to calculate the amplitude peak of Fourier Transform of Fractional Order under different rank；
In practice, by a0Centered on, it is big by Δ d such as 0.0001 of step-length in the range of ± d in such as ± 5% range
It is small, to filtered underwater sound signal Sbf(0,1) amplitude peak of Fourier Transform of Fractional Order under different rank is iterated to calculate.
Step S134: by judging that signal convergence in the domain U is best, peak swing peak value highest obtains the underwater sound markers
Signal corresponding optimal rotation angle a under Fourier Transform of Fractional Orderopt。
Step S140: intercepting filtered underwater sound timing signal, is successively divided using the optimal rotation angle
Number rank Fourier transformation, obtains each underwater sound timing signal then peak swing, remembers Fp(i)。
Step S150: seismic detector in the moment of the interval is determined using per the underwater sound timing signal peak swing deviation described twice
Clock skew inside；
In some preferred embodiments, between using being somebody's turn to do per the underwater sound timing signal peak swing deviation twice is determining
In every the seismic detector clock skew inside in the moment the step of, specifically:
Step S151: the collected underwater sound timing signal of seismic detector then peak swing F is utilizedp(i), reciprocal fraction rank Fu
In leaf transformation to convert the sampling point number in the lower domain U be u (i), note collects underwater sound timing signal peak swing F for the first timep(0) corresponding
Sampling point number u (0) be zero moment；
Step S152: by following formula, the arrival time difference for calculating underwater sound timing signal is
In formula, Δ t (i) is then deviation of the seismic detector in i underwater sound timing signal, fsFor seismic detector underwater sound timing signal
Sample frequency, aoptFor the optimal rotation angle under Fourier Transform of Fractional Order.
Step S160: resampling correction is carried out to acquisition data according to the clock skew inside, it is synchronous to obtain clock
Data.
It is appreciated that the Computing Principle of resampling correction is to take the period on the existing time shaft for waiting the sampling intervals
Clock jitter is as correcting value.First to the sampling interval of time sequence offset integral multiple.Less than one sampling interval is remained
Remaining clock deviation value first carries out zero insertion to time series.The number of significant digit of the number view Residual Clock difference of zero insertion.Then signal is carried out
FFT removes the ingredient for being higher than former nyquist frequency, then obtains the signal after interpolation by IFFT.Finally according to remaining clock
Difference deviates signal, is down-sampled, the high precision clock synchrodata after being corrected.
Embodiment 2
Referring to Fig. 2, providing the structural representation of a kind of method of seismic detector acquisition data clock for the embodiment of the present invention 2
Figure figure, for ease of description, only parts related to embodiments of the present invention are shown, and details are as follows.
In Fig. 2, the device of seismic detector acquisition data clock provided by the invention, comprising:
Signal acquiring unit 110, for obtaining underwater sound timing signal.
In some preferred embodiments, the signal acquiring unit 110 includes: the underwater sound hair being arranged in target area
Injection device, seismic detector is laid at interval in the target area, according to the number that the underwater sound emitter emits, is successively marked
It is 1,2,3 ...；
The underwater sound timing signal of the seismic detector record is denoted as S (i, j), wherein i indicates seismographic number, and j expression is adopted
The number of the underwater sound timing signal collected.
Filter unit 120 obtains filtered underwater sound markers letter for carrying out bandpass filtering to the underwater sound timing signal
Number；
In some preferred embodiments, filter unit 120 includes specifically including:
Discrete Fourier transform module, for carrying out discrete Fourier transform to the underwater sound timing signal S (i, j)；
Acquisition signal is changed into frequency domain, the public affairs by time-domain for using following formula by frequency domain conversion module
Formula are as follows:
In formula, X (k) indicate DFT transform after from time-domain to frequency domain as a result, x (n) indicate underwater sound timing signal when
Between sequence, k and n indicate identical sampling number；
First computing module, for the effective band range f according to linear frequency modulation underwater sound timing signal1-f2, will be in X (k)
Frequency range f1-f2After data in addition set 0, discrete fourier is carried out to X (k) data and changes inverse transformation, obtains filtered water
Sound timing signal Sbf(i, j).
Rotation angle computing unit 130: for carrying out Fourier Transform of Fractional Order calculating to filtered underwater sound timing signal
The optimal rotation angle of underwater sound timing signal；
In some preferred embodiments, rotation angle computing unit 130 specifically includes:
Fractional order Fourier changes module, for underwater sound timing signal S after selection filteringbfAny primary water in (i, j)
Sound timing signal carries out fractional order Fourier variation, the formula using following formula are as follows:
In formula, n is integer, FpFor the operator notation of Fourier Transform of Fractional Order, P is the rank of Fourier Transform of Fractional Order, α
=p pi/2,0 < | p | 2,0 < of < | α | < π；
Module is constructed, for constructing following formula:
In formula, fsFor the sample frequency of seismic detector underwater sound timing signal, N is sampling number, and K is the tune of linear FM signal
Frequency；
Second computing module, for a0Centered on, using step-length as Δ d in the range of ± d, when to the filtered underwater sound
Mark signal Sbf(i, j) iterates to calculate the amplitude peak of Fourier Transform of Fractional Order under different rank；
In practice, by a0Centered on, it is big by Δ d such as 0.0001 of step-length in the range of ± d in such as ± 5% range
It is small, to filtered underwater sound signal Sbf(0,1) amplitude peak of Fourier Transform of Fractional Order under different rank is iterated to calculate.
Rotation angle judgment module, for by judging that signal convergence in the domain U is best, peak swing peak value highest to be obtained
The underwater sound timing signal corresponding optimal rotation angle a under Fourier Transform of Fractional Orderopt。
Magnitude determinations unit 140 utilizes the optimal rotation angle for intercepting to filtered underwater sound timing signal
Fourier Transform of Fractional Order is successively carried out, each underwater sound timing signal then peak swing is obtained, remembers Fp(i)。
Clock jitter unit 150, for determining the interval using per the underwater sound timing signal peak swing deviation described twice
Seismic detector clock skew inside in moment；
In some preferred embodiments, clock jitter unit 150 specifically includes:
Zero moment obtains module, for utilizing the collected underwater sound timing signal of seismic detector then peak swing Fp(i), right
Answering Fourier Transform of Fractional Order to convert the sampling point number in the lower domain U is u (i), and note collects the vibration of underwater sound timing signal maximum for the first time
Width Fp(0) corresponding sampling point number u (0) is zero moment；
Third computing module, for being by the arrival time difference of following formula, calculating underwater sound timing signal
In formula, Δ t (i) is then deviation of the seismic detector in i underwater sound timing signal, fsFor seismic detector underwater sound timing signal
Sample frequency, aoptFor the optimal rotation angle under Fourier Transform of Fractional Order.
Clock synchronization data unit 160, for carrying out resampling school to acquisition data according to the clock skew inside
Just, clock synchronization data is obtained.
It is appreciated that the Computing Principle of resampling correction is to take the period on the existing time shaft for waiting the sampling intervals
Clock jitter is as correcting value.First to the sampling interval of time sequence offset integral multiple.Less than one sampling interval is remained
Remaining clock deviation value first carries out zero insertion to time series.The number of significant digit of the number view Residual Clock difference of zero insertion.Then signal is carried out
FFT removes the ingredient for being higher than former nyquist frequency, then obtains the signal after interpolation by IFFT.Finally according to remaining clock
Difference deviates signal, is down-sampled, the high precision clock synchrodata after being corrected.
Referring to Fig. 3, the transmitting of underwater sound emitter is solid for the work layout drawing that the embodiment of the present invention 1 or embodiment 2 provide
Determine the linear FM signal of frequency, habitata instrument 200 divides collected 10khz-14khz linear FM signal
Analysis, in the case where transmission medium environment and constant relative position, when the linear frequency modulation by collected fixed intervals twice
As the signal of a standard, then (this sets 300 emission signal frequency of underwater sound emitter to emit per hour after signal
Once linear FM signal), the variation at acquisition receiving time interval is exactly the deviation of habitata instrument internal time.By this
Deviation carries out resampling correction to data, to achieve the purpose that improve data clock precision.
Referring to Fig. 4, being the underwater sound signal test chart that simulation receives.It is 46kHz that one section of sample rate is simulated in Fig. 4,
Length is the data of 100ms, and wherein LFM signal is located at 20-30ms, LFM signal duration 10ms, centre frequency 12kHz, band
Wide 4kHz, frequency modulation rate is 400kHz/s, for the underwater sound signal that simulated sea bottom receives, is superimposed in former LFM basis of signals
Acquisition underwater sound timing signal of the 0dBW white noise as actual treatment.The optimal rotation angular transformation of FrFt is passed through by above-mentioned calculation method
Obtained amplitude image, it can be seen that it is corresponding with LFM signal transmission time to correspond to time 20ms position in peak swing.By multiple
The signal and actual test for simulating different background noise are as a result, the clock accuracy of test meets high definition.In practical applications due to
Underwater sound emitter and the relative position of habitata instrument are constant, and underwater sound emitter is using high-precision atomic clock between fixation
Every sending underwater sound timing signal, to acquire the underwater sound signal recognized for the first time then as initial time, multi collect identification
The variation of signal out then is exactly the clock jitter of instrument internal, acquires data to the period by the deviation and carries out resampling
Correction, so that it may obtain high-precision clock synchronization data.
The method and device of seismic detector provided by the invention acquisition data clock, to the underwater sound timing signal of acquisition into
Row bandpass filtering obtains filtered underwater sound timing signal, carries out fractional order Fourier change to filtered underwater sound timing signal
Change the optimal rotation angle for calculating underwater sound timing signal；Filtered underwater sound timing signal is intercepted, the optimal rotation is utilized
Corner successively carries out Fourier Transform of Fractional Order, obtains each underwater sound timing signal then peak swing, using per described twice
Underwater sound timing signal peak swing deviation determines seismic detector clock skew inside in the moment of the interval；According to the internal clocking
Deviation carries out resampling correction to acquisition data, obtains clock synchronization data, and seismic detector provided by the invention acquires data clock
Method and dress the linear FM signal with big time width bandwidth product is applied as a kind of pulse compression signal in the underwater sound
The influence that the complexity and multipath effect of marine environment are overcome in timing signal is believed by the transmitting linear frequency modulation of multiple timing
Number, so that the interference to single frequency point carries out certain inhibiting effect, it is better to ensure that signal has in remote situation
Signal-to-noise ratio.
In addition, the method and device of seismic detector acquisition data clock provided by the invention, after recycling habitata instrument,
Has the characteristics that energy accumulating to collected underwater sound timing signal to LFM signal using Fourier Transform of Fractional Order (FRFT)
Progress quickly then identify, can be good at inhibition time frequency analysis when cross term and reverberation, noise background under it is existing more
Pu Le influences, and obtains accurate underwater sound markers then, and it is inclined to obtain the clock inside the acquisition of habitata instrument by calculating
Difference, which have calculation method precision high, and calculation amount is suitable with FFT, and the clock jitter after correction does not increase with acquisition duration
And the features such as accumulating.
Certainly the method for seismic detector acquisition data clock of the invention can also have a variety of transformation and remodeling, it is not limited to
The specific structure of above embodiment.In short, protection scope of the present invention should include those for those of ordinary skill in the art
For obviously convert or substitute and retrofit.
Claims (10)
1. a kind of method of seismic detector acquisition data clock, which is characterized in that include the following steps:
Obtain underwater sound timing signal；
Bandpass filtering is carried out to the underwater sound timing signal, obtains filtered underwater sound timing signal；
The optimal rotation angle that Fourier Transform of Fractional Order calculates underwater sound timing signal is carried out to filtered underwater sound timing signal；
Filtered underwater sound timing signal is intercepted, successively carries out fractional order Fourier change using the optimal rotation angle
It changes, obtains each underwater sound timing signal then peak swing；
Seismic detector clock skew inside in the moment of the interval is determined using per the underwater sound timing signal peak swing deviation described twice；
Resampling correction is carried out to acquisition data according to the clock skew inside, obtains clock synchronization data.
2. the method for seismic detector acquisition data clock as described in claim 1, which is characterized in that obtaining underwater sound timing signal
The step of in, specifically include:
Underwater sound emitter is set in target area；
Seismic detector is laid at interval in the target area, according to the number that the underwater sound emitter emits, is successively labeled as
1,2,3 ...；
The underwater sound timing signal that the seismic detector records is denoted as S (i, j), wherein i indicates seismographic number, and j indicates acquisition
The number of the underwater sound timing signal arrived.
3. the method for seismic detector acquisition data clock as claimed in claim 2, which is characterized in that believe to the underwater sound markers
Number bandpass filtering is carried out, in the step of obtaining filtered underwater sound timing signal, specifically include the following steps:
Discrete Fourier transform is carried out to the underwater sound timing signal S (i, j)；
Using following formula, acquisition signal is changed into frequency domain, the formula by time-domain are as follows:
In formula, X (k) indicate DFT transform after from time-domain to frequency domain as a result, x (n) indicate underwater sound timing signal time sequence
Column, k and n indicate identical sampling number；
According to the effective band range f of linear frequency modulation underwater sound timing signal1-f2, by X (k) midband range f1-f2Data in addition
After setting 0, discrete fourier is carried out to X (k) data and changes inverse transformation, obtains filtered underwater sound timing signal Sbf(i,j)。
4. the method for seismic detector acquisition data clock as claimed in claim 2, which is characterized in that when to the filtered underwater sound
Signal is marked to carry out specifically including following steps in the step of Fourier Transform of Fractional Order calculates the optimal rotation angle of underwater sound timing signal
It is rapid:
Choose underwater sound timing signal S after filteringbfAny primary underwater sound timing signal, is divided using following formula in (i, j)
Number rank Fourier variation, the formula are as follows:
In formula, n is integer, FpFor the operator notation of Fourier Transform of Fractional Order, P is the rank of Fourier Transform of Fractional Order, α=p π/
2,0 < | p | < 2,0 < | α | < π；
Construct following formula:
In formula, fsFor the sample frequency of seismic detector underwater sound timing signal, N is sampling number, and K is the frequency modulation rate of linear FM signal；
With a0Centered on, with step-length for △ d in the range of ± d, to filtered underwater sound timing signal Sbf(i, j) iterative calculation
The amplitude peak of Fourier Transform of Fractional Order under different rank；
By judging that signal convergence in the domain U is best, peak swing peak value highest obtains the underwater sound timing signal in fractional order
Corresponding optimal rotation angle a under Fourier transformationopt。
5. the method for seismic detector acquisition data clock as described in claim 1, which is characterized in that using per the water described twice
In the step of sound timing signal peak swing deviation determines seismic detector clock skew inside in the moment of the interval, specifically:
Utilize the collected underwater sound timing signal of seismic detector then peak swing Fp(i), under the transformation of reciprocal fraction rank Fourier transformation
The sampling point number in the domain U is u (i), and note collects underwater sound timing signal peak swing F for the first timep(0) corresponding sampling point number u (0)
For zero moment；
By following formula, the arrival time difference for calculating underwater sound timing signal is
In formula, Δ t (i) is then deviation of the seismic detector in i underwater sound timing signal, fsFor adopting for seismic detector underwater sound timing signal
Sample frequency, aoptFor the optimal rotation angle under Fourier Transform of Fractional Order.
6. a kind of device of seismic detector acquisition data clock characterized by comprising
Signal acquiring unit, for obtaining underwater sound timing signal；
Filter unit obtains filtered underwater sound timing signal for carrying out bandpass filtering to the underwater sound timing signal；
Rotation angle computing unit calculates underwater sound markers for carrying out Fourier Transform of Fractional Order to filtered underwater sound timing signal
The optimal rotation angle of signal；
Magnitude determinations unit, for being intercepted to filtered underwater sound timing signal, using the optimal rotation angle successively into
Row Fourier Transform of Fractional Order obtains each underwater sound timing signal then peak swing；
Clock jitter unit, for using per the underwater sound timing signal peak swing deviation described twice with determining in the moment of the interval
Shake instrument clock skew inside；
Clock synchronization data unit is obtained for carrying out resampling correction to acquisition data according to the clock skew inside
Clock synchronization data.
7. the device of seismic detector acquisition data clock as claimed in claim 6, which is characterized in that the signal acquiring unit packet
It includes: the underwater sound emitter in target area, the interval laying seismic detector in the target area is set, according to the underwater sound
The number of emitter transmitting, is successively labeled as 1,2,3 ...；
The underwater sound timing signal of the seismic detector record is denoted as S (i, j), wherein i indicates seismographic number, and j expression collects
Underwater sound timing signal number.
8. the method for seismic detector as claimed in claim 6 acquisition data clock, which is characterized in that filter unit includes:
Discrete Fourier transform module, for carrying out discrete Fourier transform to the underwater sound timing signal S (i, j)；
Acquisition signal is changed into frequency domain, the formula by time-domain for using following formula by frequency domain conversion module
Are as follows:
In formula, X (k) indicate DFT transform after from time-domain to frequency domain as a result, x (n) indicate underwater sound timing signal time sequence
Column, k and n indicate identical sampling number；
First computing module, for the effective band range f according to linear frequency modulation underwater sound timing signal1-f2, by X (k) midband
Range f1-f2After data in addition set 0, discrete fourier is carried out to X (k) data and changes inverse transformation, when obtaining the filtered underwater sound
Mark signal Sbf(i,j)。
9. the method for seismic detector acquisition data clock as claimed in claim 6, which is characterized in that rotation angle computing unit packet
It includes:
Fractional order Fourier changes module, for underwater sound timing signal S after selection filteringbfIn (i, j) when the arbitrarily primary underwater sound
Signal is marked, carries out fractional order Fourier variation, the formula using following formula are as follows:
In formula, n is integer, FpFor the operator notation of Fourier Transform of Fractional Order, P is the rank of Fourier Transform of Fractional Order, α=p π/
2,0 < | p | < 2,0 < | α | < π；
Module is constructed, for constructing following formula:
In formula, fsFor the sample frequency of seismic detector underwater sound timing signal, N is sampling number, and K is the frequency modulation rate of linear FM signal；
Second computing module, for a0Centered on, with step-length for △ d in the range of ± d, filtered underwater sound markers is believed
Number Sbf(i, j) iterates to calculate the amplitude peak of Fourier Transform of Fractional Order under different rank；
Rotation angle judgment module, for by judging that signal convergence in the domain U is best, peak swing peak value highest to obtain the water
Sound timing signal corresponding optimal rotation angle a under Fourier Transform of Fractional Orderopt。
10. the method for seismic detector acquisition data clock as claimed in claim 6, which is characterized in that the clock jitter unit
Include:
Zero moment obtains module, utilizes the collected underwater sound timing signal of seismic detector then peak swing Fp(i), reciprocal fraction rank
The sampling point number that Fourier transformation converts the lower domain U is u (i), and note collects underwater sound timing signal peak swing F for the first timep(0) right
The sampling point number u (0) answered is zero moment；
Third computing module, for being by the arrival time difference of following formula, calculating underwater sound timing signal
In formula, Δ t (i) is then deviation of the seismic detector in i underwater sound timing signal, fsFor adopting for seismic detector underwater sound timing signal
Sample frequency, aoptFor the optimal rotation angle under Fourier Transform of Fractional Order.
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