CN104049249B - The high-precise synchronization of anti-multifrequency aliasing surveys chi phase laser distance apparatus and method - Google Patents
The high-precise synchronization of anti-multifrequency aliasing surveys chi phase laser distance apparatus and method Download PDFInfo
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- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
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Abstract
The high-precise synchronization of anti-multifrequency aliasing is surveyed chi phase laser distance apparatus and method and is belonged to phase laser distance technology, and described range unit includes surveying chi and generates unit, laser shift frequency unit, anti-aliasing optical path and phase measurement cells composition；Its distance-finding method comprises the following steps that step one, open frequency benchmark laser and rrequency-offset-lock He-Ne laser instrument；Step 2, a branch of as reference laser beam, another Shu Zuowei Laser Measurement；Step 3, withAs accurate measurement chi；Step 4, withAs bigness scale chi；Step 5, traverse measurement angle vertebra prism, to destination end, respectively obtain the phase contrast of accurate measurement chi and bigness scale chi<i>Φ</i>1With<i>Φ</i>2, obtain tested distance value finally by formula；The invention solves overlength wavelength and ultrashort wavelength can not synchronize produce, Laser Measuring chi is not directly traced to the source and the problem of non-linear cycle error and frequency alias, has that measurement efficiency is high, precision is high, stability and a real-time feature.
Description
Technical field
The invention belongs to laser measuring technique, relate generally to a kind of phase laser distance apparatus and method.
Background technology
Large-scale metrology receives much concern in the large-scale optical, mechanical and electronic integration equipment processing and manufacturings such as development large-scale precision machine-building, great science and technology engineering, aerospace industry, shipping industry and microelectronics equipment industry, wherein several meters of large-scale metrologies to hundreds of rice scope are the large parts processing in aerospace vehicle and jumbo ship and the overall important foundation assembled, the quality of its measuring method and equipment performance directly affects workpiece quality and assembly precision, and then affects the running quality of complete equipment, performance and life-span.Chi phase ranging methods of surveying utilize one group of survey chi wavelength from big to small that tested distance is carried out refining accuracy measurement more, what solve between measurement scope and certainty of measurement is conflicting, can reach submillimeter to micron-sized static measurement precision in hundreds of meters overlength operating distance.
Survey in chi phase laser distance technology more, although the mode that many survey chis are measured step by step has taken into account the demand of measurement scope and certainty of measurement, but the restriction due to light source technology, bigness scale chi and accurate measurement chi can not produce line phase measurement of going forward side by side simultaneously, cause measurement overlong time, the problem of measurement result poor real, on the other hand owing to being sized to benchmark survey in chi phase laser distance technology more and measure surveying chi wavelength, the stability surveying chi wavelength directly affects the precision of laser ranging, therefore bigness scale chi and the accurate measurement chi wavelength of high stability how are obtained, and measure, so as to simultaneously participate in, the subject matter being to improve many survey chi phase laser distance precision at present with real-time.
The stability surveying chi is relevant with light source technology with synchronization generation technology, by analyzing it can be seen that the modulation means of phase method has electric current directly modulation, light modulation and intermode beats frequency modulation etc. both at home and abroad at present the LASER Light Source technology of phase laser distance method.
Direct current modulation method utilizes semiconductor laser, light intensity curent change and the feature that changes, and the output intensity carrying out noise spectra of semiconductor lasers is modulated, and has the advantages such as simple easily modulation.Document [SiyuanLiu, JiubinTanandBinkeHou.MulticycleSynchronousDigitalPhaseMe asurementUsedtoFurtherImprovePhase-ShiftLaserRangeFindin g.Meas.Sci.Technol.2007, 18:1756 1762] and patent [the large range high precision fast laser ranging apparatus and method of multiple frequency synchronous modulation, publication number: CN1825138] all elaborate the current modulating method of a kind of based semiconductor laser instrument, it adopts the composite signal that multiple frequency synchronous synthesizes that laser output power is carried out synchronous modulation, achieve and obtain in multifrequency modulation range finding each modulation frequency for the measurement result of tested distance at synchronization, but in order to obtain linear modulation, operating point is made to be in the straight line portion of output characteristic curve, must while adding modulation signal code the suitable bias current that add to make it export signal undistorted, the introducing of direct current biasing increases power consumption, when working long hours, temperature raises, the stability of Output optical power can be affected, cause that modulation waveform deforms, and along with the increase of modulating frequency, modulation depth can reduce, cause that modulation waveform deforms, high frequency modulated can not be carried out, limit size and the degree of stability of accurate measurement chi wavelength；In the actual application of large-scale metrology, laser easily causes the loss of laser power in long range propagation process on the other hand, cause the impact on modulation waveform, and then affecting the accuracy and degree of stability of surveying chi, its frequency stability surveying chi is generally less than 10-7。
Light modulating method is utilized to be mainly acousto-optic modulation method and electro-optic modulation method, its modulation bandwidth is subject to the multifactorial impact of laser beam spot sizes etc., also bring along waveform distortions, particularly just even more serious when high frequency (Gigahertz), therefore it is formed big survey chi, and certainty of measurement is difficult to improve owing to being subject to the restriction of maximum modulation frequency.
Utilize the beat signal that the output of laser instrument different mode is formed as the method surveying chi, be called that intermode is modulated.The chamber appearance of the modulation bandwidth of the method and laser instrument is closed, He-Ne laser frequency stabilization technology is ripe, its frequency stability is high, the degree of stability surveying chi obtained by it is high, patent [high accuracy multiple frequency synchronous phase laser distance apparatus and method, publication number: CN102419166] and patent [the multiple frequency synchronous phase laser distance apparatus and method based on dual-acousto-optic shift, publication number: CN102305591A] all make use of the intermode of He-Ne laser instrument to modulate and in conjunction with acousto-optic frequency translation technology, obtain high-precision accurate measurement chi and bigness scale chi, but the produced chi of surveying of the method does not possess tractability, when it is measured, absolute measuring chi length needs another detection system to provide, add the complexity of measurement；On the other hand, this method utilizing heterodyne method to obtain accurate measurement chi phase place, its frequency processing signal is higher, can follow-up phase measurement difficulty and certainty of measurement be affected, it is assumed that phase-measurement accuracy is 0.05o, range measurement accuracy to reach 1um-10um, then signal frequency is at least 2GHz-20GHz, the remote bandwidth beyond signal processing circuit now.
Patent [superheterodyne device and method of reseptance and receive device semiconductor integrated circuit, publication number: CN102484492A] all describe a kind of superhet interference signal treatment technology, Tsing-Hua University Zhang Cunman [Zhang Cunman etc., superhet interferes absolute distance measurement Review Study, optical technology 1998, (1): 7-9.] describe superhet absolute distance measurement method, this method reduce the process frequency of signal, it is easier to reach higher certainty of measurement.But this technology has three aspects needing to improve: first, and this technology can only obtain one and surveys chi, and do not possess tractability, it is impossible to carry out chi of surveying more and measure, let alone the synchronicity surveying chi more；Second, it is less that superhet obtains surveying chi wavelength, is typically in micron dimension, is only used for the measurement of the micro-shape in surface.3rd, owing to using multi-frequency measurement and traditional anti-aliasing optical path with polarization spectroscope, inevitably produce non-linear cycle error and frequency alias, the certainty of measurement of phase place is impacted.
In order to improve the stability of laser instrument output frequency, occur in that using the Output of laser frequency of iodine saturated absorption frequency stabilization laser instrument as the frequency-stabilizing method of frequency stabilization benchmark, utilize the saturated absorption spectra of iodine that He-Ne laser instrument and semiconductor laser are carried out rrequency-offset-lock control.China has been also carried out research, such as patent ZL200910072518.5 and patent ZL200910072519.X etc. all describe a kind of rrequency-offset-lock device utilizing iodine saturated absorption He-Ne frequency stabilized carbon dioxide laser, the laser output frequency after rrequency-offset-lock is made to have significantly high frequency stability, there is the advantage that output frequency can be traced to the source, but the output frequency of laser reaches 1014Hz, corresponding survey chi is between 400-700nm, and scope of measuring is in nm rank, it is impossible to find range for long distance laser, needs a kind of survey chi of laser ranging on a large scale high frequency stability laser frequency being converted to and can tracing to the source badly, and synchronizes them the technology of generation.
In sum, in laser ranging field, there are three problems needs to solve, and first, the synchronization of overlength wavelength and ultrashort wavelength produces, so as to take into account certainty of measurement and measurement scope, second, high accuracy can be traced to the source and be surveyed the generation of chi, to improve the accuracy surveying chi wavelength, and reduce the step that measurement wavelength needs other system to provide, and the 3rd, reduce non-linear cycle error and the frequency alias impact on certainty of measurement.The present invention is directed to these three problem to propose a solution.
Summary of the invention
The invention aims to solve in existing phase laser distance technology exist overlength wavelength and ultrashort wavelength can not synchronize produce, Laser Measuring chi is not directly traced to the source and the problem of non-linear cycle error and frequency alias, the high-precise synchronization providing a kind of anti-multifrequency aliasing surveys chi phase laser distance apparatus and method, reaches to increase range finding motility, simplifies ranging step, improves the purpose measuring efficiency, precision and real-time.
The object of the present invention is achieved like this:
The high-precise synchronization of a kind of anti-multifrequency aliasing surveys chi phase laser distance device, it is characterized in that: described device is formed by surveying chi generation unit, laser shift frequency unit, anti-aliasing optical path and phase measurement cells, the laser that wherein survey chi generation unit sends exports the input of laser shift frequency unit, anti-aliasing optical path, the output signal I of anti-aliasing optical path are arrived in the output beam of laser shift frequency unit and output3, I4, I5, I6It is separately input to phase measurement cells；
Described survey chi generates the structure of unit: the laser beam that frequency reference laser instrument is launched arrives the input of beam splitter, first outfan of beam splitter connects a He-Ne laser input, a number He-Ne laser output connects the input of a polaroid, second outfan of described beam splitter connects No. two He-Ne laser input, the outfan of No. two He-Ne laser instrument connects the input of No. two polaroids, 3rd outfan of beam splitter connects No. three He-Ne laser input, the outfan of No. three He-Ne laser instrument connects the input of No. three polaroids；
The structure of described laser shift frequency unit is: the input of a half-wave plate connects the outfan of a polaroid, the outfan of a number half-wave plate connects the input of a polarization spectroscope, one outfan of a number polarization spectroscope connects the input of a reflecting mirror, another outfan of a number polarization spectroscope connects an input of a laser splicer, the outfan of a number reflecting mirror connects an input of a laser frequency shifter, the outfan of a number DDS signal source connects another input of a laser frequency shifter, the outfan of a number laser frequency shifter connects the input of No. three reflecting mirrors, the outfan of No. three reflecting mirrors connects an input of No. two laser splicers, spectroscopical input connects the outfan of No. two polaroids, a spectroscopical outfan connects the input of No. two reflecting mirrors, another outfan spectroscopical connects an input of a laser splicer, the outfan of No. two reflecting mirrors connects an input of No. two laser frequency shifters, another input of No. two laser frequency shifters connects the outfan of No. two DDS signal sources, the outfan of No. two laser frequency shifters connects an input of No. two laser splicers, one input of a described laser splicer connects the outfan of No. three polaroids, No. two laser splicer output reference laser light beams, a number laser splicer output measuring laser beam；
The structure of described anti-aliasing optical path is: No. two spectroscopes of reference laser light beam directive, laser beam a is formed through No. two dichroic mirror entering angle cone prisms, it is transmitted into reference prism through No. two spectroscopes and forms laser beam b, laser beam a is reflected back into No. two spectroscopes by prism of corner cube, laser beam c is formed then through No. two spectroscope transmissions, reflect to form laser beam d, laser beam b is reflected back into No. two spectroscopes by reference prism, laser beam e is formed then through No. two spectroscope transmissions, reflect to form laser beam f, No. two spectroscopes of described measuring laser beam directive, it is transmitted into measuring prism through No. two spectroscopes and forms laser beam g, it is reflected into prism of corner cube and forms laser beam h, laser beam f is reflected into No. two spectroscopes through measuring prism, laser beam j is formed then through No. two spectroscope transmissions, reflect to form laser beam i, laser beam h is reflected into No. two spectroscopes through prism of corner cube, laser beam l is formed then through No. two spectroscope transmissions, reflect to form laser beam k, described laser beam c overlaps with laser beam i, and the input of a photelectric receiver is entered through No. four polaroids, described laser beam d overlaps with laser beam j, and the input of No. two photelectric receivers is entered through No. five polaroids, described laser beam e overlaps with laser beam k, and the input of No. four photelectric receivers is entered through No. seven polaroids, described laser beam f overlaps with laser beam l, and the input of No. three photelectric receivers is entered through No. six polaroids；
The structure of described phase measurement cells is: the outfan of a photelectric receiver and No. four photelectric receivers is connected with the input of a low pass filter and No. two low pass filters respectively, a number low pass filter and the outfan of No. two low pass filters are connected with the input of frequency mixer, the outfan of frequency mixer connects the input of phase measurement meter, No. two photelectric receivers and No. four photelectric receivers are connected with the input of No. three low pass filters and No. four low pass filters respectively, the outfan of No. three low pass filters and No. four low pass filters is connected with the input of phase measurement meter.
The high-precise synchronization of a kind of anti-multifrequency aliasing is surveyed chi phase laser distance measuring method and is specifically comprised the following steps that
Step one, open frequency benchmark laser, one, two, No. three He-Ne laser instrument, after preheating, by feedback control output frequency is being locked within the certain frequency scope of frequency reference laser instrument, from No. three He-Ne laser instrument send laser after polaroid only surplus frequency be v1Horizontal polarization direction laser, from a He-Ne laser instrument send laser after polaroid only surplus frequency be v2Horizontal polarization direction laser, it is v that No. two He-Ne laser instrument send laser remaining frequency after polaroid3Vertical polarization laser；
Step 2, the three beams of laser formed by step one enter laser shift frequency unit, and its medium frequency is v2Laser beam, after half-wave plate and a polarization spectroscope, separate the two mutually perpendicular laser in bundle polarization direction, wherein a road is through laser frequency shifter, by DDS signal source drive laser frequency shifter, shift frequency frequency is f1, another road not shift frequency, frequency is v3Laser after spectroscope, be also classified into two-way one tunnel through laser frequency shifter, shift frequency frequency is f2, the laser of last various frequencies has five kinds of frequencies, respectively v2、v3、v1、v2+f1And v3+f2, through the conjunction light of laser splicer, it is v by frequency2+f1And v3+f2Laser synthesizing a branch of, formed reference laser light beam, frequency is v2、v3、v1Laser synthesizing measuring laser beam, and shine anti-aliasing optical path respectively；
Step 3, reference laser light beam are divided into laser beam a and laser beam b through No. two spectroscopes, measuring laser beam is divided into laser beam g and laser beam h through No. two spectroscopes, laser beam b and laser beam h is respectively after reference prism and prism of corner cube reflect, a bit joining on No. two spectroscope light splitting surfaces forms two beam interferometer light beams, and wherein a light beam is through polarization direction and v1No. six polaroids becoming 45 degree enter No. three photelectric receivers and carry out opto-electronic conversion, and again through obtaining comprising the signal of telecommunication of accurate measurement chi signal phase information after No. four low pass filters, its frequency is f1-f2, corresponding survey chi length is, another light beam is through polarization direction and v1After No. seven identical polaroids, obtaining frequency is v1、v2The laser of horizontal polarization direction, enter back into No. four photelectric receivers and carry out opto-electronic conversion, the signal of telecommunication obtained frequency of its output signal of telecommunication after No. two low pass filters is v1-v2, corresponding survey chi length is；
When step 4, measurement start, reference prism maintains static, traverse measurement prism is to destination end, measurement distance is L, laser beam g is after measuring prism reflects, converge at No. two another some places spectroscopical with laser beam a and form interfering beams, form two beam interferometer laser then through spectroscope light splitting, wherein a branch of through polarization direction and v1No. five polaroids becoming 45 degree enter No. two photelectric receivers and carry out opto-electronic conversion, and again through obtaining comprising the signal of telecommunication of accurate measurement chi signal phase information after No. three low pass filters, its frequency is f1-f2, corresponding survey chi length is, another light beam is through polarization direction and v1After No. four identical polaroids, obtaining frequency is v1、v2The laser of horizontal polarization direction, enter back into a photelectric receiver and carry out opto-electronic conversion, the signal of telecommunication obtained frequency of its output signal of telecommunication after a low pass filter is v1-v2, corresponding survey chi length is；
Step 5, it is v by frequency1-v2Two signals access frequency mixers, reduce the frequency of two signals, be then fed into phase measurement meter, obtain the phase contrast Φ of two frequencies1, it is f by frequency1-f2The signal of telecommunication send into phase measurement meter carry out survey phase, obtain the phase contrast Φ of two signals2, according to formulaTry to achieve the distance measure L of bigness scale chic, and substituted into formula and try to achieve the phase integer value of accurate measurement chi；Floor (x) function returns the integer part of x value, tries to achieve tested distance value finally according to formula:, in formula: c is the light velocity, n is the air refraction of environment.
The feature of the present invention and providing the benefit that:
First, the present invention proposes a kind of trace to the source same pacing chi production method and device based on He-Ne laser instrument, these apparatus and method utilize frequency reference type frequency stabilized carbon dioxide laser that the Output of laser of three He-Ne laser instrument is carried out rrequency-offset-lock control, and utilize the laser after frequency stabilization to form laser ranging accurate measurement chi with superhet form, heterodyne form forms bigness scale chi, make thick, accurate measurement chi wavelength can directly be traceable to frequency/wavelength reference model frequency stabilized carbon dioxide laser, and lock point can be adjusted according to actual needs, and then accurate measurement chi wavelength is adjusted, add the motility of range finding, overcome and existing range unit is surveyed the shortcoming that chi is not directly traced to the source, simplify general range unit and survey the step that chi wavelength needs another detection system to provide when absolute measuring is long, improve measurement efficiency and precision, this is one of present invention innovative point distinguishing existing apparatus.
Second, the present invention proposes a kind of many surveys chi Phase synchronization acquisition methods being combined based on heterodyne and device with superhet.These apparatus and method utilize laser frequency shifter that the laser of component frequency is carried out shift frequency, produce the laser of multi-frequency, and utilize heterodyne approach and superhet approach to obtain bigness scale chi and accurate measurement chi respectively simultaneously, and then so as to simultaneously participate in measurement, achieve the synchro measure of coarse-fine survey chi phase place, shorten the measurement time, improve the real-time of measurement result.The laser interferometry combined with superhet by heterodyne obtains test phase signal, eliminate common mode disturbances, improve the degree of stability surveying chi, reduce phase measuring circuit simultaneously and receive the frequency of signal, reducing the difficulty of circuit design, this is that the present invention distinguishes the two of the innovative point of existing apparatus.
3rd, the present invention proposes a kind of multi-frequency anti-aliasing interference technique and device.In these apparatus and method, reference light and measurement light reach anti-aliasing optical path through different paths, in interferoscope group in anti-aliasing optical path, reference light and measurement light perform twice at through different paths and interfere the measurement realized tested distance, owing to two light beams are without aliasing, eliminate due to optics or light source polarization direction undesirable and produce polarized light reveal and aliasing, thus avoiding non-linear cycle error and frequency alias error in principle.This is that the present invention distinguishes the three of the innovative point of existing apparatus.
Accompanying drawing explanation
Fig. 1 is the population structure schematic diagram of the laser ranging system of the present invention；
Fig. 2 surveys chi to generate the structural representation of unit；
Fig. 3 is the structural representation of laser shift frequency unit；
Fig. 4 is reference signal beam interference schematic diagram；
Fig. 5 interferes schematic diagram for measuring signal beams；
Fig. 6 is anti-aliasing optical path structural representation；
Fig. 7 is phase measurement cells structural representation
In figure, piece number illustrates: 1, survey chi and generate unit, 2, laser shift frequency unit, 3, anti-aliasing optical path, 4, phase measurement cells, 5, frequency reference laser instrument, 6, beam splitter, 7, a number He-Ne laser instrument, 8, a number polaroid, 9, No. two He-Ne laser instrument, 10, No. two polaroids, 11, No. three He-Ne laser instrument, 12, No. three polaroids, 13, a number half-wave plate, 14, a number polarization spectroscope, 15, a number reflecting mirror, 16, a number laser frequency shifter, 17, a number DDS signal source, 18, spectroscope, 19, No. two reflecting mirrors, 20, No. two laser frequency shifters, 21, No. two DDS signal sources, 22, No. three reflecting mirror groups, 23, a number laser splicer, 24, No. two laser splicers, 25, reference laser light beam, 26, measuring laser beam, 27, No. two spectroscopes, 28, prism of corner cube, 29, measuring prism, 30, reference prism, 31, a number photelectric receiver, 32, No. four polaroids, 33, No. five polaroids, 34, No. two photelectric receivers, 35, No. six polaroids, 36, No. three photelectric receivers, 37, No. seven polaroids, 38, No. four photelectric receivers, 39, a number low pass filter, 40, No. two low pass filters, 41, No. three low pass filters, 42, No. four low pass filters, 43, frequency mixer, 44, phase measurement meter.
Detailed description of the invention
Below in conjunction with accompanying drawing, embodiment of the present invention is described in detail.
The high-precise synchronization of a kind of anti-multifrequency aliasing surveys chi phase laser distance device, it is characterized in that: described device is formed by surveying chi generation unit 1, laser shift frequency unit 2, anti-aliasing optical path 3 and phase measurement cells 4, the laser that wherein survey chi generation unit 1 sends exports the input of laser shift frequency unit 2, anti-aliasing optical path 3, the output signal I of anti-aliasing optical path 3 are arrived in the output reference laser light beam 25 of laser shift frequency unit 2 and measuring laser beam 26 output3, I4, I5, I6It is separately input to phase measurement cells 4；
Described survey chi generates the structure of unit 1: the laser beam that frequency reference laser instrument 5 is launched arrives the input of beam splitter 6, first outfan of beam splitter 6 connects He-Ne laser instrument 7 input, number He-Ne laser instrument 7 outfan connects the input of a polaroid 8, second outfan of described beam splitter 6 connects No. two He-Ne laser instrument 9 inputs, the outfan of No. two He-Ne laser instrument 9 connects the input of No. two polaroids 10, 3rd outfan of beam splitter 6 connects No. three He-Ne laser instrument 11 inputs, the outfan of No. three He-Ne laser instrument 11 connects the input of No. three polaroids 12；
The structure of described laser shift frequency unit 2 is: the input of a half-wave plate 13 connects the outfan of a polaroid (8), the outfan of a number half-wave plate 13 connects the input of a polarization spectroscope 14, one outfan of a number polarization spectroscope 14 connects the input of a reflecting mirror 15, another outfan of a number polarization spectroscope 14 connects an input of a laser splicer 23, the outfan of a number reflecting mirror 15 connects an input of a laser frequency shifter 16, the outfan of a number DDS signal source 17 connects another input of a laser frequency shifter 16, the outfan of a number laser frequency shifter 16 connects the input of No. three reflecting mirrors 22, the outfan of No. three reflecting mirrors 22 connects an input of No. two laser splicers 24, the input of spectroscope 18 connects the outfan of No. two polaroids 10, one outfan of spectroscope 18 connects the input of No. two reflecting mirrors 19, another outfan of spectroscope 18 connects an input of a laser splicer 23, the outfan of No. two reflecting mirrors 19 connects an input of No. two laser frequency shifters 20, another input of No. two laser frequency shifters 20 connects the outfan of No. two DDS signal sources 21, the outfan of No. two laser frequency shifters 20 connects an input of No. two laser splicers 24, one input of a described laser splicer 23 connects the outfan of No. three polaroids 12, No. two laser splicers 24 export reference laser light beam 25, a number laser splicer 23 exports measuring laser beam 26；
The structure of described anti-aliasing optical path 3 is: No. two spectroscopes 27 of reference laser light beam 25 directive, it is reflected into prism of corner cube 28 through No. two spectroscopes 27 and forms laser beam a25-1, it is transmitted into reference prism 30 through No. two spectroscopes 27 and forms laser beam b25-2, laser beam a25-1 is reflected back into No. two spectroscopes 27 by prism of corner cube 28, laser beam c25-3 is formed then through No. two spectroscope 27 transmissions, reflect to form laser beam d25-4, laser beam b25-2 is reflected back into No. two spectroscopes 27 by reference prism 30, laser beam e25-5 is formed then through No. two spectroscope 27 transmissions, reflect to form laser beam f25-6, described No. two spectroscopes 27 of measuring laser beam 26 directive, it is transmitted into measuring prism 29 through No. two spectroscopes 27 and forms laser beam g26-1, it is reflected into prism of corner cube 28 and forms laser beam h26-2, laser beam f26-1 is reflected into No. two spectroscopes 27 through measuring prism 29, laser beam j26-4 is formed then through No. two spectroscope 27 transmissions, reflect to form laser beam I26-3, laser beam h26-2 is reflected into No. two spectroscopes 27 through prism of corner cube 28, laser beam l26-6 is formed then through No. two spectroscope 27 transmissions, reflect to form laser beam k26-5, described laser beam c25-3 overlaps with laser beam I26-3, and the input of a photelectric receiver 31 is entered through No. four polaroids 32, described laser beam d25-4 overlaps with laser beam j26-4, and the input of No. two photelectric receivers 34 is entered through No. five polaroids 33, described laser beam e25-5), overlap with laser beam k26-5, and the input of No. four photelectric receivers 38 is entered through No. seven polaroids 37, described laser beam f25-6 overlaps with laser beam l26-6, and the input of No. three photelectric receivers 36 is entered through No. six polaroids 35；
The structure of described phase measurement cells 4 is: a photelectric receiver 31 is connected with the input of a low pass filter 39 and No. two low pass filters 40 respectively with the outfan of No. four photelectric receivers 38, a number low pass filter 39 is connected with the input of frequency mixer 43 with the outfan of No. two low pass filters 40, the outfan of frequency mixer 43 connects the input of phase measurement meter 44, No. two photelectric receivers 34 are connected with the input of No. three low pass filters 41 and No. four low pass filters 42 respectively with No. four photelectric receivers 38, No. three low pass filters 42 are connected with the input of phase measurement meter 44 with the outfan of No. four low pass filters 42.
One, No. two laser frequency shifters 16,20 of described laser shift frequency unit 2 include acousto-optic frequency shifters, electro-optic frequency translation device, and travel frequency can regulate.
It is the rrequency-offset-lock laser instrument based on frequency reference laser instrument that described survey chi generates one, two, No. three He-Ne laser instrument 7,9,11 in unit 1.
Described survey chi generates unit 1 medium frequency benchmark laser 5 and includes iodine stabilizd laser, femtosecond laser frequency comb laser instrument, and frequency stability is better than 10-12。
The high-precise synchronization of a kind of anti-multifrequency aliasing is surveyed chi phase laser distance measuring method and is specifically comprised the following steps that
Step one, open frequency benchmark laser 5, one, two, No. three He-Ne laser instrument 7,9,11, after preheating, by feedback control output frequency is locked within the certain frequency scope of frequency reference laser instrument 5, from No. three He-Ne laser instrument 11 send laser after polaroid only surplus frequency be v1Horizontal polarization direction laser, from a He-Ne laser instrument 7 send laser after polaroid only surplus frequency be v2Horizontal polarization direction laser, it is v that No. two He-Ne laser instrument 9 send laser remaining frequency after polaroid3Vertical polarization laser；
Step 2, the three beams of laser formed by step one enter laser shift frequency unit 2, and its medium frequency is v2Laser beam, after half-wave plate and a polarization spectroscope 14, separate the two mutually perpendicular laser in bundle polarization direction, wherein a road is through laser frequency shifter, by DDS signal source drive laser frequency shifter, shift frequency frequency is f1, another road not shift frequency, frequency is v3Laser after spectroscope, be also classified into two-way one tunnel through laser frequency shifter, shift frequency frequency is f2, the laser of last various frequencies has five kinds of frequencies, respectively v2、v3、v1、v2+f1And v3+f2, through the conjunction light of laser splicer 23,24, it is v by frequency2+f1And v3+f2Laser synthesizing a branch of, formed reference laser light beam 25, frequency is v2、v3、v1Laser synthesizing measuring laser beam 26, and shine anti-aliasing optical path respectively；
Step 3, reference laser light beam 25 are divided into laser beam a25-1 and laser beam b25-2 through No. two spectroscopes 27, measuring laser beam 26 is divided into laser beam g26-1 and laser beam h26-2 through No. two spectroscopes 27, laser beam b25-2 and laser beam h26-2 is respectively after reference prism 30 and prism of corner cube 28 reflect, a bit joining on No. two spectroscope 27 light splitting surfaces forms two beam interferometer light beams, and wherein a light beam is through polarization direction and v1No. six polaroids 35 becoming 45 degree enter No. three photelectric receivers 36 and carry out opto-electronic conversion, and again through obtaining comprising the signal of telecommunication of accurate measurement chi signal phase information after No. four low pass filters 42, its frequency is f1-f2, corresponding survey chi length is, another light beam is through polarization direction and v1After No. seven identical polaroids 37, obtaining frequency is v1、v2The laser of horizontal polarization direction, enter back into No. four photelectric receivers 38 and carry out opto-electronic conversion, the signal of telecommunication obtained frequency of its output signal of telecommunication after No. two low pass filters is v1-v2, corresponding survey chi length is；
When step 4, measurement start, reference prism 30 maintains static, traverse measurement prism 29 to destination end, measurement distance is L, laser beam g26-1 is after measuring prism 29 reflects, converge at another some place of No. two spectroscopes 27 with laser beam a25-1 and form interfering beam, form two beam interferometer laser then through spectroscope light splitting, wherein a branch of through polarization direction and v1No. five polaroids 33 becoming 45 degree enter No. two photelectric receivers 34 and carry out opto-electronic conversion, and again through obtaining comprising the signal of telecommunication of accurate measurement chi signal phase information after No. three low pass filters 41, its frequency is f1-f2, corresponding survey chi length is, another light beam is through polarization direction and v1After No. four identical polaroids 32, obtaining frequency is v1、v2The laser of horizontal polarization direction, enter back into a photelectric receiver 31 and carry out opto-electronic conversion, the signal of telecommunication obtained frequency of its output signal of telecommunication after a low pass filter 29 is v1-v2, corresponding survey chi length is；
Step 5, it is v by frequency1-v2Two signals access frequency mixers 43, reduce the frequency of two signals, be then fed into phase measurement meter 44, obtain the phase contrast Φ of two frequencies1, it is f by frequency1-f2The signal of telecommunication send into phase measurement meter 44 carry out survey phase, obtain the phase contrast Φ of two signals2, according to formulaTry to achieve the distance measure L of bigness scale chic, and substituted into formula and try to achieve the phase integer value of accurate measurement chi；Floor (x) function returns the integer part of x value, tries to achieve tested distance value finally according to formula:, in formula: c is the light velocity, n is the air refraction of environment.
Described two path signal phase contrast Φ1With phase contrast Φ2Measurement carry out at synchronization.
Described laser frequency v2And v3Can trace to the source to frequency reference laser instrument, the accurate measurement chi formedCan trace to the source.
Claims (7)
1. the high-precise synchronization of an anti-multifrequency aliasing surveys chi phase laser distance device, it is characterized in that: described device is formed by surveying chi generation unit (1), laser shift frequency unit (2), anti-aliasing optical path (3) and phase measurement cells (4), the laser that wherein survey chi generation unit (1) sends exports the input of laser shift frequency unit (2), anti-aliasing optical path (3), the output signal I of anti-aliasing optical path (3) are arrived in output reference laser light beam (25) of laser shift frequency unit (2) and measuring laser beam (26) output3, I4, I5, I6It is separately input to phase measurement cells (4)；
Described survey chi generates the structure of unit (1): the laser beam that frequency reference laser instrument (5) is launched arrives the input of beam splitter (6), first outfan of beam splitter (6) connects He-Ne laser instrument (7) input, number He-Ne laser instrument (7) outfan connects the input of a polaroid (8), second outfan of described beam splitter (6) connects No. two He-Ne laser instrument (9) inputs, the outfan of No. two He-Ne laser instrument (9) connects the input of No. two polaroids (10), 3rd outfan of beam splitter (6) connects No. three He-Ne laser instrument (11) inputs, the outfan of No. three He-Ne laser instrument (11) connects the input of No. three polaroids (12)；
The structure of described laser shift frequency unit (2) is: the input of a half-wave plate (13) connects the outfan of a polaroid (8), the outfan of a number half-wave plate (13) connects the input of a polarization spectroscope (14), one outfan of a number polarization spectroscope (14) connects the input of a reflecting mirror (15), another outfan of a number polarization spectroscope (14) connects an input of a laser splicer (23), the outfan of a number reflecting mirror (15) connects an input of a laser frequency shifter (16), the outfan of a number DDS signal source (17) connects another input of a laser frequency shifter (16), the outfan of a number laser frequency shifter (16) connects the input of No. three reflecting mirrors (22), the outfan of No. three reflecting mirrors (22) connects an input of No. two laser splicers (24), the input of spectroscope (18) connects the outfan of No. two polaroids (10), one outfan of spectroscope (18) connects the input of No. two reflecting mirrors (19), another outfan of spectroscope (18) connects an input of a laser splicer (23), the outfan of No. two reflecting mirrors (19) connects an input of No. two laser frequency shifters (20), another input of No. two laser frequency shifters (20) connects the outfan of No. two DDS signal sources (21), the outfan of No. two laser frequency shifters (20) connects an input of No. two laser splicers (24), one input of a described laser splicer (23) connects the outfan of No. three polaroids (12), No. two laser splicers (24) output reference laser light beam (25), a number laser splicer (23) output measuring laser beam (26)；
The structure of described anti-aliasing optical path (3) is: No. two spectroscopes (27) of reference laser light beam (25) directive, it is reflected into prism of corner cube (28) through No. two spectroscopes (27) and forms laser beam a(25-1), it is transmitted into reference prism (30) through No. two spectroscopes (27) and forms laser beam b(25-2), laser beam a(25-1) reflected back into No. two spectroscopes (27) by prism of corner cube (28), laser beam c(25-3 is formed) then through No. two spectroscope (27) transmissions, reflect to form laser beam d(25-4), laser beam b(25-2) reflected back into No. two spectroscopes (27) by reference prism (30), laser beam e(25-5 is formed) then through No. two spectroscope (27) transmissions, reflect to form laser beam f(25-6), No. two spectroscopes (27) of described measuring laser beam (26) directive, it is transmitted into measuring prism (29) through No. two spectroscopes (27) and forms laser beam g(26-1), it is reflected into prism of corner cube (28) and forms laser beam h(26-2), laser beam f(26-1) it is reflected into No. two spectroscopes (27) through measuring prism (29), laser beam j(26-4 is formed) then through No. two spectroscope (27) transmissions, reflect to form laser beam i(26-3), laser beam h(26-2) it is reflected into No. two spectroscopes (27) through prism of corner cube (28), laser beam l(26-6 is formed) then through No. two spectroscope (27) transmissions, reflect to form laser beam k(26-5), described laser beam c(25-3) with laser beam i(26-3) overlap, and the input of a photelectric receiver (31) is entered through No. four polaroids (32), described laser beam d(25-4) with laser beam j(26-4) overlap, and the input of No. two photelectric receivers (34) is entered through No. five polaroids (33), described laser beam e(25-5) with laser beam k(26-5) overlap, and the input of No. four photelectric receivers (38) is entered through No. seven polaroids (37), described laser beam f(25-6) with laser beam l(26-6) overlap, and the input of No. three photelectric receivers (36) is entered through No. six polaroids (35)；
The structure of described phase measurement cells (4) is: a photelectric receiver (31) is connected with the input of a low pass filter (39) and No. two low pass filters (40) respectively with the outfan of No. four photelectric receivers (38), a number low pass filter (39) is connected with the input of frequency mixer (43) with the outfan of No. two low pass filters (40), the outfan of frequency mixer (43) connects the input of phase measurement meter (44), No. two photelectric receivers (34) are connected with the input of No. three low pass filters (41) and No. four low pass filters (42) respectively with No. four photelectric receivers (38), No. three low pass filters (41) are connected with the input of phase measurement meter (44) with the outfan of No. four low pass filters (42).
2. the high-precise synchronization of anti-multifrequency aliasing according to claim 1 surveys chi phase laser distance device, it is characterized in that: one, No. two laser frequency shifters (16,20) of described laser shift frequency unit (2) include acousto-optic frequency shifters, electro-optic frequency translation device, and travel frequency can regulate.
3. the high-precise synchronization of anti-multifrequency aliasing according to claim 1 surveys chi phase laser distance device, it is characterised in that: it is the rrequency-offset-lock laser instrument based on frequency reference laser instrument that described survey chi generates one, two, No. three He-Ne laser instrument (7,9,11) in unit (1).
4. the high-precise synchronization of anti-multifrequency aliasing surveys chi phase laser distance device according to claim 1, it is characterized in that: described survey chi generates unit (1) medium frequency benchmark laser (5) and includes iodine stabilizd laser, femtosecond laser frequency comb laser instrument, and frequency stability is better than 10-12。
5. the high-precise synchronization of an anti-multifrequency aliasing as claimed in claim 1 surveys the distance-finding method of chi phase laser distance device, it is characterised in that: specifically comprise the following steps that
Step one, open frequency benchmark laser (5), one, two, No. three He-Ne laser instrument (7,9,11), after preheating, by feedback control output frequency is locked within the certain frequency scope of frequency reference laser instrument (5), from No. three He-Ne laser instrument (11) send laser after polaroid only surplus frequency be v1Horizontal polarization direction laser, from a He-Ne laser instrument (7) send laser after polaroid only surplus frequency be v2Horizontal polarization direction laser, it is v that No. two He-Ne laser instrument (9) send laser remaining frequency after polaroid3Vertical polarization laser；
Step 2, the three beams of laser formed by step one enter laser shift frequency unit (2), and its medium frequency is v2Laser beam, after half-wave plate and a polarization spectroscope (14), separate the two mutually perpendicular laser in bundle polarization direction, wherein a road is through laser frequency shifter, by DDS signal source drive laser frequency shifter, shift frequency frequency is f1, another road not shift frequency, frequency is v3Laser after spectroscope, be also classified into two-way one tunnel through laser frequency shifter, shift frequency frequency is f2, the laser of last various frequencies has five kinds of frequencies, respectively v2、v3、v1、v2+f1And v3+f2, through the conjunction light of laser splicer (23) (24), it is v by frequency2+f1And v3+f2Laser synthesizing a branch of, formed reference laser light beam (25), frequency is v2、v3、v1Laser synthesizing measuring laser beam (26), and shine anti-aliasing optical path respectively；
Step 3, reference laser light beam (25) are divided into laser beam a(25-1 through No. two spectroscopes (27)) and laser beam b(25-2), measuring laser beam (26) is divided into laser beam g(26-1 through No. two spectroscopes (27)) and laser beam h(26-2), laser beam b(25-2) and laser beam h(26-2) respectively after reference prism (30) and prism of corner cube (28) reflect, a bit joining on No. two spectroscope (27) light splitting surfaces forms two beam interferometer light beams, and wherein a light beam is through polarization direction and v1No. six polaroids (35) becoming 45 degree enter No. three photelectric receivers (36) and carry out opto-electronic conversion, and again through obtaining comprising the signal of telecommunication of accurate measurement chi signal phase information after No. four low pass filters (42), its frequency is f1-f2, corresponding survey chi length is, another light beam is through polarization direction and v1After No. seven identical polaroids (37), obtaining frequency is v1、v2The laser of horizontal polarization direction, enter back into No. four photelectric receivers (38) and carry out opto-electronic conversion, the signal of telecommunication obtained frequency of its output signal of telecommunication after No. two low pass filters is v1-v2, corresponding survey chi length is；
When step 4, measurement start, reference prism (30) maintains static, traverse measurement prism (29) is to destination end, measurement distance is L, laser beam g(26-1) after measuring prism (29) reflects, with laser beam a(25-1) converge at another some place of No. two spectroscopes (27) and to form interfering beam, form two beam interferometer laser then through spectroscope light splitting, wherein a branch of through polarization direction and v1No. five polaroids (33) becoming 45 degree enter No. two photelectric receivers (34) and carry out opto-electronic conversion, and again through obtaining comprising the signal of telecommunication of accurate measurement chi signal phase information after No. three low pass filters (41), its frequency is f1-f2, corresponding survey chi length is, another light beam is through polarization direction and v1After No. four identical polaroids (32), obtaining frequency is v1、v2The laser of horizontal polarization direction, enter back into a photelectric receiver (31) and carry out opto-electronic conversion, the signal of telecommunication obtained frequency of its output signal of telecommunication after a low pass filter (29) is v1-v2, corresponding survey chi length is；
Step 5, it is v by frequency1-v2Two signals access frequency mixer (43), reduce the frequency of two signals, be then fed into phase measurement meter (44), obtain the phase contrast Φ of two frequencies1, it is f by frequency1-f2The signal of telecommunication send into phase measurement meter (44) carry out survey phase, obtain the phase contrast Φ of two signals2, according to formulaTry to achieve the distance measure L of bigness scale chic, and substituted into formula and try to achieve the phase integer value of accurate measurement chi；Floor (x) function returns the integer part of x value, tries to achieve tested distance value finally according to formula:, in formula: c is the light velocity, n is the air refraction of environment.
6. the high-precise synchronization of anti-multifrequency aliasing according to claim 5 surveys the distance-finding method of chi phase laser distance device, it is characterised in that: described two path signal phase contrast Φ1With phase contrast Φ2Measurement carry out at synchronization.
7. the high-precise synchronization of anti-multifrequency aliasing according to claim 5 surveys the distance-finding method of chi phase laser distance device, it is characterised in that: described laser frequency v2And v3Can trace to the source to frequency reference laser instrument, the accurate measurement chi formedCan trace to the source.
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