CN101986095A - Ground marking method for eliminating time drift of crystal oscillator - Google Patents
Ground marking method for eliminating time drift of crystal oscillator Download PDFInfo
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- CN101986095A CN101986095A CN 201010283157 CN201010283157A CN101986095A CN 101986095 A CN101986095 A CN 101986095A CN 201010283157 CN201010283157 CN 201010283157 CN 201010283157 A CN201010283157 A CN 201010283157A CN 101986095 A CN101986095 A CN 101986095A
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Abstract
The invention discloses a ground marking method for eliminating time drift of a crystal oscillator and relates to the field of detection in pipelines. The method comprises the following steps of: coding ground markers before an internal detector is sent into a pipeline; performing time synchronization on the internal detector and the ground markers through a master clock; sending the internal detector into the pipeline for operation; placing the ground markers on ground marking piles; starting the ground markers to acquire data when the internal detector is close to the ground markers; recording the time when the internal detector passes through the ground markers; storing the recorded time when the internal detector passes through the ground markers into the ground markers; taking the internal detector out of the pipeline, and calibrating each ground marker for the second time; and transmitting the internal detector passing time recorded by the ground markers and data recorded by the internal detector to a supervisory computer for processing so as to realize the positioning of pipeline defects. By the method, the influence of clock drift is effectively eliminated, the detection precision of the ground markers is improved, and the positions of the pipeline defects are accurately positioned.
Description
Technical field
The present invention relates to pipeline detection land mark field, particularly a kind of land mark method of eliminating the crystal oscillator time drift.
Background technology
Develop rapidly along with pipeline industry, increasing of pipeline, manage the growth in age, the manufacturing defect of pipeline itself, constructional deficiency and corrosion and artificial destruction etc., pipeline accident takes place again and again, have a strong impact on the normal operation of pipeline and physical environment on every side, the safe reliability problem of pipeline becomes increasingly conspicuous.Signal Processing and digital storage system that the pipeline detection technology is utilized high-precision lossless detection equipment, advanced person advance under the promotion of oil gas, finish pipeline is scanned step by step, realize the accurate location to defect of pipeline such as pipe deforming, corrosion and crackles.In order to obtain defect of pipeline in ducted position, location and ground marking system are realized the accurate location to defective in the pipeline detection system employing mileage wheel.The mileage wheel is installed on the internal detector, by the angle that record mileage wheel turns over, extrapolates the distance that internal detector is advanced in pipeline.But owing to mileage wheel abrasion deformation, skid and the influence of factor such as swing, error appears in mileage wheel location easily, and average every km error is 1m, after up to a hundred kilometers operations, will cause the cumulative errors of dozens or even hundreds of rice, can not satisfy requirement of engineering.In order to eliminate the cumulative errors of mileage wheel, above pipeline is along the line, place ground marking system on the known location, detect and write down the precise time that internal detector thereunder passes through, as shown in Figure 1.Because therefore the clock of ground marking system and the time synchronized of internal detector can be benchmark the time, the distance of internal detector mileage wheel record is corrected to the position at ground marking system place.By placing a ground marking system every 1-2km along the line at pipeline, the error of mileage wheel is calibrated once every 1-2km, and then eliminates the cumulative errors of mileage wheel.
At present the employed ground marking system in various countries can accurately detect in-pipeline detector and passes through in pipeline, even bury also can very sensitive detecting in dark, the pipeline that tube wall is thicker.But existing ground marking system mainly is subjected to the restriction of ground marking system and internal detector timing tracking accuracy by the accuracy of detection of time to internal detector.Existing ground marking system adopts gps time with the same footwork of footwork or high stability clock source mostly.Gps time need all be installed gps receiver with footwork on each ground marking system, cost and power consumption are all quite high.
The high stability clock source is before internal detector is sent into pipeline that the zero-time of its zero-time and ground marking system is synchronous with footwork, because the both adopts the temperature compensating crystal oscillator of high stable or temperature control crystal oscillator as the clock source, therefore in whole pipe in the testing process, the time of internal detector remains consistent with the time of ground marking system.This method has been reduced cost and power consumption widely, but also has certain shortcoming.Though the caused clock drift of temperature can be eliminated in the high stability clock source, but because variation, pollutant effects, the variation of mechanical stress and the chemical reaction of metal electrode of crystal oscillator material, will cause crystal oscillator to produce frequency change with extending service time, service time is long more, it is big more to depart from original frequency, very big to the time synchronized influence.
Nineteen ninety-five, 5417112 pairs of United States Patent (USP)s were owing to the measuring error that clock drift causes is calibrated, the ground marking system of this invention records the time of internal detector by pipeline welding, and internal detector itself can detect its time by pipeline welding simultaneously.If the clock frequency of the clock frequency of ground marking system and internal detector is different, then to record internal detector respectively also just different by the time at same weld place for ground marking system and internal detector.Therefore can between get one time calibration the factor both frequency drift is compensated, thereby revised two clock sources the time float, eliminated the influence of clock drift to measurement result.This method must accurately be measured by the time of welding internal detector, and subsequent treatment need calculate the linear gauging factors to a plurality of weld seams, and hardware relative complex, algorithm difficulty are big, can not satisfy portability, low-power consumption and requirement cheaply; Because the influence of propagation delay time and this body structure of internal detector, the internal detector that ground marking system and internal detector record respectively is different by the time at same weld place, it is equal that this scheme is calibrated both times, thereby introduced error, influences the accuracy of defect location.
Summary of the invention
In order to eliminate the influence of clock drift to measurement result, improve the accuracy of detection of ground marker, the position of targeted duct defective accurately, satisfy portability, low-power consumption and requirement cheaply, the invention provides a kind of land mark method of eliminating the crystal oscillator time drift, said method comprising the steps of:
(1) before internal detector is sent into pipeline, each ground marker is numbered, described internal detector, each described ground marker are carried out time synchronized by master clock;
(2) described internal detector is sent in the pipeline moved, each described ground marker is placed on stake place of corresponding land mark;
(3) when described internal detector when the described ground marker, open described ground marker, acquired signal, the conversion of signals that collects is become electric signal, after processing and amplifying, Filtering Processing and A/D conversion process, carry out analyzing and processing, if recognize signal is the signal of described internal detector by described ground marker, then write down the time of described internal detector by described ground marker, the described ground marker of the record time by described ground marker is stored in the described ground marker;
(4) after interior detection task is finished, described internal detector is taken out from pipeline, each described ground marker is carried out secondary demarcate, eliminate crystal oscillator time drift error;
(5) the described internal detector with each described ground marker record arrives host computer by the time of described ground marker and the data transmission of described internal detector record itself, contrast the moment place of the described internal detector of each described ground marker record by described ground marker, the mileage of described internal detector record itself, revise the mileage measuring error of described internal detector, realize location defect of pipeline.
After interior detection task is finished, described internal detector is taken out from pipeline described in the step (4), each described ground marker is carried out secondary demarcate, eliminate crystal oscillator time drift error, specifically comprise:
Calculate the linear gauging factor-alpha of described master clock to described internal detector;
Calculate the linear gauging factor gamma of each described ground marker, and described internal detector was calibrated by the time of described ground marker described internal detector.
The described master clock of described calculating is specially the linear gauging factor-alpha of described internal detector:
Described master clock and described internal detector are coupled together by communication interface, send trigger pulse by described master clock, described master clock and described internal detector are noted current separately clock count value N0, clock count value N1 simultaneously, by data communication interface described clock count value N1 is transferred to described master clock again, the main control chip of described master clock calculates the linear gauging factor-alpha, and be stored in the storer α=N0/N1 wherein.
Each described ground marker of described calculating is to the linear gauging factor gamma of described internal detector, and described internal detector was calibrated by the time of described ground marker, is specially:
Described master clock and described ground marker are coupled together by communication interface, send trigger pulse by described master clock, make described master clock and described ground marker simultaneously with current separately clock count value M0, clock count value M1 notes, by data communication interface described clock count value M0 and described linear gauging factor-alpha are transferred to described ground marker again, digital processing unit in the described ground marker calculates described ground marker to the linear gauging factor-beta of described master clock with to the linear gauging factor gamma of described internal detector, β=M1/M0 wherein, γ=α * β multiply by γ with the described internal detector of storing in the storer by the time again and calibrates.
The beneficial effect of technical scheme provided by the invention is:
The land mark method of elimination crystal oscillator time drift provided by the invention can be eliminated the influence of clock drift to measurement result effectively, improves the accuracy of detection of ground marker, accurately the position of targeted duct defective; And data processing is simple, to hardware circuit require lowly, power consumption and cost are also low, and very large advantage is arranged in modern pipe detection.
Description of drawings
The ground marker that Fig. 1 provides for prior art detects the principle schematic that in-pipeline detector passes through under the pipeline;
The structured flowchart of the ground marker that Fig. 2 provides for prior art;
The structured flowchart of the master clock that Fig. 3 provides for prior art;
Fig. 4 is for ground marker provided by the invention and master clock carries out synchronously and the hardware connection layout of secondary demarcation;
Fig. 5 is the process flow diagram of the detection method of elimination crystal oscillator time drift provided by the invention;
Fig. 6 is the process flow diagram that secondary provided by the invention is demarcated.
In the accompanying drawing, the list of parts of each label representative is as follows:
1: ground; 2: pipeline;
3: in-pipeline detector; 4: ground marker;
5: ground marker; 6: the land mark stake;
7: the land mark stake; 8: internal detector by the time leakage field, electromagnetism or the acoustical signal that produce.
Embodiment
For making the purpose, technical solutions and advantages of the present invention clearer, embodiment of the present invention is described further in detail below in conjunction with accompanying drawing.
In order to eliminate the influence of clock drift to measurement result, improve the accuracy of detection of ground marker, the position of targeted duct defective accurately, satisfy portability, low-power consumption and requirement cheaply, the embodiment of the invention provides a kind of land mark method of eliminating the crystal oscillator time drift, referring to Fig. 2, Fig. 3, Fig. 4, Fig. 5 and Fig. 6, see for details hereinafter and describe:
The embodiment of the invention is carried out the ground marking system of time synchronized based on the existing high stable clock source that utilizes with footwork, and this ground marking system comprises ground marker and master clock two parts.The structured flowchart of ground marker as shown in Figure 2, ground marker comprises and is used to experience internal detector by sonic transducer (can also be Magnetic Sensor, electromagnetic receiver); The amplifier that the signal that connects sonic transducer and sonic transducer is received amplifies; The low-pass filter of filter away high frequency noise signal; The A/D converter that connects low-pass filter; The digital signal processor that connects A/D converter; The high-capacity and high-speed storer that is used for storage signal of linking number word signal processor; Be used for interface with the master clock communication; The crystal oscillator of high stability clock is provided for ground marker; Pilot lamp and hummer that button and indication internal detector pass through.Utilize sonic transducer to survey the signal that internal detector passes through, measure internal detector through the time under the ground marker, and utilize indication staff internal detectors such as pilot lamp or hummer to pass through.
Referring to Fig. 3, master clock comprises main control chip, storer, crystal oscillator, the communication interface that is connected with ground marker, the communication interface that is connected with in-pipeline detector and button etc., and this master clock is used for the time synchronized and the secondary of ground marker and in-pipeline detector and demarcates.
Ground marker and master clock carry out the hardware of time synchronized and secondary demarcation and form as shown in Figure 4, wherein, in the main control chip of the digital processing unit of ground marker and master clock clock counter is arranged all, clock counter is used for the crystal oscillator clock is counted, and obtains the standard time that current count value takes place as incident.Crystal oscillator in ground marker and the master clock all adopts high stability, temperature compensating crystal oscillator or temperature control crystal oscillator that the short-term time drift is little.Be made up of trigger pulse passage and data communication interface with the communication interface that is connected with ground marker with the interface of master clock communication, data communication interface is used for data transmission, and the trigger pulse passage is used to send trigger pulse.
In-pipeline detector and master clock carry out hardware that time synchronized and secondary demarcate and form with Fig. 4 similarly, are used to realize the time synchronized and the secondary demarcation of internal detector and master clock.
Above-mentioned crystal oscillator is little temperature compensating crystal oscillator of degree of stability height, short-term time drift or temperature control crystal oscillator, after long-term the use, because clock drift causes the frequency departure standard frequency bigger.
101: before internal detector is sent into pipeline, each ground marker is numbered, internal detector, each ground marker are carried out time synchronized by master clock;
This step was specially before internal detector is sent into pipeline, master clock and internal detector by communication interface with the zero clearing simultaneously of clock count value, by data communication interface pre-set count values is transferred to ground marker by master clock, when the clock count value of master clock arrives pre-set count values, make the clock counter of ground marker begin counting from pre-set count values by sending trigger pulse.Pre-set count values is bigger slightly than master clock present clock count value, reserves time enough and supplies master clock marker transmission pre-set count values earthward.
102: internal detector sent in the pipeline move, each ground marker is placed on stake place of corresponding land mark;
Wherein, this step is specially generally and every 1-2km a land mark stake is set along pipeline, as the permanent marks of pipeline top.When detecting in carrying out ground marker is placed on land mark stake place, the residing land mark stake numbering of record ground marker is promptly known the residing position of ground marker at every turn.Carry out defectives such as geometry deformation, metal erosion, crackle after pipeline detection finishes when searching, only needing with the land mark stake be that reference point carries out segment lookup to pipeline.
103: when internal detector during near ground marker, open ground marker, acquired signal, the conversion of signals that collects is become electric signal, after processing and amplifying, Filtering Processing and A/D conversion process, carry out analyzing and processing, be the signal of internal detector if recognize signal by ground marker, then write down the time of internal detector, the time of ground marker by ground marker of record is stored in the ground marker by ground marker;
Wherein, this step is specially when internal detector during near ground marker, opens ground marker and begins acquired signal, and sensor becomes electric signal with the conversion of signals that collects, after amplification, filtering, A/D conversion etc. are handled, send into digital processing unit and carry out analyzing and processing.If recognizing this electric signal is the signal of internal detector by ground marker, the clock count value of corresponding ground marker when then noting internal detector by ground marker.Simultaneously digital processing unit signal that the in-pipeline detector that collects is passed through with and the clock count value passed through store in the ground marker.
Further, in order to reduce power consumption and cost, this method also comprises: after internal detector passes through ground marker, with current ground marker dormancy, only keep crystal oscillator and clock counter work.
Be specially: pass through by prompting staff internal detector land mark stakes place from then on such as pilot lamp and hummers, make the staff in time change this ground marker into dormant state, and notify the staff of next land mark stake to prepare to open ground marker.Next ground marker is started working, and repeated execution of steps 103 is all finished mark to internal detector until all land mark stakes place.
Further, in order to recycle ground marker, save cost, reduce the ground marker number of time synchronized and secondary mark simultaneously, this method also comprises: the ground marker of land mark stake place that the upstream internal detector has been passed through is fetched, and this ground marker is placed into also unsanctioned land mark stake place of downstream internal detector.
104: after interior detection task is finished, internal detector is taken out from pipeline, each ground marker is carried out secondary demarcate, eliminate crystal oscillator time drift error;
This secondary is demarcated and mainly be may further comprise the steps:
1041: calculate the linear gauging factor-alpha of master clock to internal detector;
This step is specially: master clock and internal detector are coupled together by communication interface, send trigger pulse by master clock, master clock and internal detector are noted current separately clock count value N0, clock count value N1 simultaneously, by data communication interface clock count value N1 is transferred to master clock again.The main control chip of master clock calculates the linear gauging factor-alpha, and is stored in the storer, wherein α=N0/N1.
1042: calculate the linear gauging factor gamma of each ground marker, and the time of passing through ground marker of internal detector is calibrated to internal detector.
Master clock and ground marker are coupled together by communication interface, send trigger pulse by master clock, master clock and ground marker are noted current separately clock count value M0, clock count value M1 simultaneously, by data communication interface clock count value M0 and linear gauging factor-alpha are transferred to ground marker again.Digital processing unit in the ground marker calculates ground marker to the linear gauging factor-beta of master clock with to the linear gauging factor gamma of internal detector.Wherein the computing formula of β is β=M1/M0, the computing formula of γ is γ=α * β, the time that the internal detector of storing in the storer is passed through be multiply by γ again, crystal oscillator with internal detector is a benchmark like this, the time calibration that the internal detector that ground marker is measured passes through, it was different with the crystal oscillator frequency of ground marker and asynchronism(-nization) that cause goes on foot problem to have solved the internal detector that is caused by clock drift to the time of the internal detector of correspondence.
Calibrate follow-up ground marker record successively, last, other ground marker is also taked the secondary scaling method of above-mentioned steps 1041-1042, the internal detector that each ground marker is measured was calibrated by the time.
105: the internal detector of each ground marker record is arrived host computer by the time of ground marker and the data transmission of internal detector record itself, contrast the moment place of the internal detector of each ground marker record by ground marker, the mileage of internal detector record itself, revise the mileage measuring error of internal detector, realize location defect of pipeline.
Wherein, the data of internal detector record itself comprise: data messages such as defect of pipeline information, mileage value, these information all are corresponding mutually, the all corresponding mileage value of each defect of pipeline information, and mileage value error is too big, ground marker can will be somebody's turn to do the error correction of mileage value constantly by measuring the time of internal detector by ground marker.Therefore the location to defect of pipeline can be a starting point with the ground marker position just, according to the increment of defect of pipeline place mileage value with respect to the ground marker place, and accurate targeted duct defective just.
This step is specially: according to the internal detector of ground marker record by ground marker the moment, search the mileage value at the place of corresponding moment in the internal detector record data, the mileage value is adapted on the residing position of ground marker.Then, be reference point with the ground marker present position again, according to the increment of defect of pipeline place mileage value, accurately orient defect of pipeline with respect to land mark place mileage value.
In sum, the embodiment of the invention provides a kind of land mark method of eliminating the crystal oscillator time drift, by this method, can eliminate the influence of clock drift to measurement result effectively, improve the accuracy of detection of ground marker, accurately the position of targeted duct defective; And data processing is simple, the accuracy of detection height, to hardware circuit require lowly, power consumption and cost are also low, and very large advantage is arranged in modern pipe detection.
It will be appreciated by those skilled in the art that accompanying drawing is the synoptic diagram of a preferred embodiment, the invention described above embodiment sequence number is not represented the quality of embodiment just to description.
The above only is preferred embodiment of the present invention, and is in order to restriction the present invention, within the spirit and principles in the present invention not all, any modification of being done, is equal to replacement, improvement etc., all should be included within protection scope of the present invention.
Claims (4)
1. a land mark method of eliminating the crystal oscillator time drift is characterized in that, said method comprising the steps of:
(1) before internal detector is sent into pipeline, each ground marker is numbered, described internal detector, each described ground marker are carried out time synchronized by master clock;
(2) described internal detector is sent in the pipeline moved, each described ground marker is placed on stake place of corresponding land mark;
(3) when described internal detector when the described ground marker, open described ground marker, acquired signal, the conversion of signals that collects is become electric signal, after processing and amplifying, Filtering Processing and A/D conversion process, carry out analyzing and processing, if recognize signal is the signal of described internal detector by described ground marker, then write down the time of described internal detector by described ground marker, the described ground marker of the record time by described ground marker is stored in the described ground marker;
(4) after interior detection task is finished, described internal detector is taken out from pipeline, each described ground marker is carried out secondary demarcate, eliminate crystal oscillator time drift error;
(5) the described internal detector with each described ground marker record arrives host computer by the time of described ground marker and the data transmission of described internal detector record itself, contrast the moment place of the described internal detector of each described ground marker record by described ground marker, the mileage of described internal detector record itself, revise the mileage measuring error of described internal detector, realize location defect of pipeline.
2. the land mark method of elimination crystal oscillator time drift according to claim 1, it is characterized in that, described in the step (4) after interior detection task is finished, described internal detector is taken out from pipeline, each described ground marker is carried out secondary to be demarcated, eliminate crystal oscillator time drift error, specifically comprise:
Calculate the linear gauging factor-alpha of described master clock to described internal detector;
Calculate the linear gauging factor gamma of each described ground marker, and described internal detector was calibrated by the time of described ground marker described internal detector.
3. the land mark method of elimination crystal oscillator time drift according to claim 2 is characterized in that, the described master clock of described calculating is specially the linear gauging factor-alpha of described internal detector:
Described master clock and described internal detector are coupled together by communication interface, send trigger pulse by described master clock, described master clock and described internal detector are noted current separately clock count value N0, clock count value N1 simultaneously, by data communication interface described clock count value N1 is transferred to described master clock again, the main control chip of described master clock calculates the linear gauging factor-alpha, and be stored in the storer α=N0/N1 wherein.
4. the land mark method of elimination crystal oscillator time drift according to claim 2, it is characterized in that, each described ground marker of described calculating is to the linear gauging factor gamma of described internal detector, and described internal detector was calibrated by the time of described ground marker, is specially:
Described master clock and described ground marker are coupled together by communication interface, send trigger pulse by described master clock, make described master clock and described ground marker simultaneously with current separately clock count value M0, clock count value M1 notes, by data communication interface described clock count value M0 and described linear gauging factor-alpha are transferred to described ground marker again, digital processing unit in the described ground marker calculates described ground marker to the linear gauging factor-beta of described master clock with to the linear gauging factor gamma of described internal detector, β=M1/M0 wherein, γ=α * β multiply by γ with the described internal detector of storing in the storer by the time again and calibrates.
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| CN2010102831571A CN101986095B (en) | 2010-09-14 | 2010-09-14 | Ground marking method for eliminating time drift of crystal oscillator |
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| CN2010102831571A CN101986095B (en) | 2010-09-14 | 2010-09-14 | Ground marking method for eliminating time drift of crystal oscillator |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN107923991A (en) * | 2015-03-26 | 2018-04-17 | 英国石油勘探运作有限公司 | Earthquake exploration method |
| CN108107433A (en) * | 2017-12-05 | 2018-06-01 | 北京无线电计量测试研究所 | One kind is used for the pinpoint method of millimetre-wave radar system |
| CN112709864A (en) * | 2020-12-07 | 2021-04-27 | 深圳市燃气集团股份有限公司 | Pipeline defect positioning method and system |
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| CN101260976A (en) * | 2008-04-17 | 2008-09-10 | 中国特种设备检测研究院 | Pipeline leakage checking system |
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| US5417112A (en) * | 1993-01-11 | 1995-05-23 | Tdw Delaware, Inc. | Apparatus for indicating the passage of a pig moving within an underground pipeline |
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| CN107923991A (en) * | 2015-03-26 | 2018-04-17 | 英国石油勘探运作有限公司 | Earthquake exploration method |
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| CN108107433A (en) * | 2017-12-05 | 2018-06-01 | 北京无线电计量测试研究所 | One kind is used for the pinpoint method of millimetre-wave radar system |
| CN108107433B (en) * | 2017-12-05 | 2023-03-03 | 北京无线电计量测试研究所 | Method for accurately positioning millimeter wave radar system |
| CN112709864A (en) * | 2020-12-07 | 2021-04-27 | 深圳市燃气集团股份有限公司 | Pipeline defect positioning method and system |
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