CN100394211C - Multi-frequency synchronous modified large range high precision fast laser ranging method and apparatus - Google Patents
Multi-frequency synchronous modified large range high precision fast laser ranging method and apparatus Download PDFInfo
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- CN100394211C CN100394211C CNB2006100729905A CN200610072990A CN100394211C CN 100394211 C CN100394211 C CN 100394211C CN B2006100729905 A CNB2006100729905 A CN B2006100729905A CN 200610072990 A CN200610072990 A CN 200610072990A CN 100394211 C CN100394211 C CN 100394211C
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Abstract
The present invention belongs to the technical field of laser distance measurement, particularly to a large range high precision rapid laser distance measurement method and a device based on multi-frequency synchronous modification. After a laser transmitting unit conducts characteristic precompensation, weighting and summation synthesis to multi-frequency modulation signals, the power of a laser is modulated and the laser measures distance. Simultaneously, a mode of synchronous band pass filtering frequency selection phase measurement, which is corresponding to the modulation method, is used for processing the signals when the signals are received, and the existing mode of multi-frequency serial asynchronous modulation distance measurement is changed into a mode of parallel synchronous modulation. With the method and the device of the present invention, distance measurement results of the frequency of measuring tapes in the multi-frequency modulation distance measurement can be obtained at the same moment. Therefore, a final distance measurement value is obtained, and distance measurement speed and real-time performance can be ensured. On one hand, the present invention can rapidly measure target distance on the basis of ensuring measurement precision and large ranges, and on the other hand, distance measurement errors caused by the position change of a target are avoided when multi-frequency time sharing measurement is used for measuring the distance of moving targets.
Description
Technical field
The invention belongs to the laser ranging technique field, particularly a kind of large range high precision fast laser ranging method and device based on the multiple frequency synchronous modulation.
Background technology
Laser ranging is that multiple technologies such as light harvesting, laser, photoelectron and integrated electronic are the integrated technology of one.The semiconductor laser range device is widely used in fields such as military affairs, space flight, robot vision, industrial automatic assembly line because of advantages such as it has noncontact, precision height, volume is little, cost is low, long service life.At absolute distance measurement, laser distance measurement method commonly used at present has impulse method and phase method.It is wide that the impulse method range finding has measurement range, and speed is fast, is applicable to advantages such as noncooperative target, but its measuring accuracy is low.Adopt the distance measuring equipment ranging of impulse type semiconductor laser can reach several kilometers, precision is generally 0.1～1m.The common measuring speed of phase method is slow, but can obtain millimeter even higher distance accuracy, so more applications is in the range finding occasion higher to accuracy requirement.
Laser Range Finding Based on Phase be with intensity by the laser beam irradiation of certain frequency modulation to target, by measuring between emission of lasering beam and target reflection laser beam because the phase differential that target range causes comes measuring distance.Tested distance can be provided by formula (1)
Wherein: D is tested distance, and c is the light velocity, and f is a modulating frequency,
Be emission light signal and receiving optical signals phase differential.Because the phase difference measurements can only be between 0～2 π, so the theoretical maximum ranging D of this distance-finding method in the actual measurement process
MaxBy modulating frequency decision, D
Max=c/2 π f will increase ranging and just must reduce modulating frequency.Get and this is declined:
By formula (2) as can be known in phase-measurement accuracy
The identical low more distance accuracy of condition modulated frequency f is low more, and measuring accuracy and range produce contradiction.But in a lot of application scenarios, not only require the distance measuring equipment ranging far away, also require measuring accuracy height and measuring speed fast.At Laser Range Finding Based on Phase and range and precision contradictory problems, a lot of patents and research method have been arranged both at home and abroad.
Switzerland Lycra company is at its patent (US5815251, EP0738899, EP0932835) the DISTO series hand-held laser rangefinder of releasing on the basis, adopt the range finding of multifrequency phase method, maximum ranging is 200m, full accuracy is ± 3.0mm that the single measurement time is the shortest to be 0.16s (Switzerland blocks the Leica DISTO of company series laser range finder product description, 2004).
Document " a kind of double frequency modulated laser stadimeter " (Stephane Poujouly and Bernard Journet, Atwofold modulation frequency laser range finder, J.Opt A:Pur Appt.Opt.4 (2002) s356-S363) set forth a kind of laser ranging device using phase method that adopts the double frequency modulation in, its modulating frequency is chosen 10MHz and 240MHz respectively, ranging is 15m, and precision is 0.35mm.
The DCH2-E N-type semiconductor N infrared range-measurement system of Tsing-Hua University and the development of Beijing instrument of surveying and mapping factory, adopted the laser ranging of double frequency phase modulation method, modulation frequency adopts indirect frequency back-and-forth method, accurate measurement chi frequency is 14.985520MHz, bigness scale chi frequency is 149.856KHz, maximum ranging is 2000m, precision ± 10mm, and the single measurement time is 5.0s.
Above-mentioned existing distance measuring equipment and research have all been adopted identical method on the contradiction that solves Laser Range Finding Based on Phase range and precision, i.e. multifrequency modulation method, and this method also is the method that existing research institute generally adopts.Multifrequency phase modulation method laser distance measuring principle as shown in Figure 1, it mainly is made up of 9 parts, is respectively multiple-frequency signal generating unit 4, multi-channel electronic switch 3 and 8, laser power modulation driver element 2, laser instrument 1, laser pick-off camera lens 5, measuring light photodetector 6, measuring light photoelectric switching circuit 7, difference measurements and apart from synthesis unit 9 mutually.This method adopts multiple modulating frequency that target is found range, and wherein low-frequency modulation signal (bigness scale chi frequency) is in order to increase measurement range, and high-frequency modulation signal (accurate measurement chi frequency) is in order to guarantee measuring accuracy.Each modulation signal of control unit controls electronic switch timesharing gating is found range to target during measurement, and then each is surveyed the resulting distance measurement value of chi carry out Data Fusion, and then draws final range finding result.The weak point of the method mainly shows as following 2 points: the one, and measuring speed is slow, needs to carry out the multifrequency gradation to target during measurement and measures, and obtains final measurement by data fusion then, always the time of finding range increases with the increase of modulation frequency number; The 2nd, when moving target was found range, the target location may change in the multifrequency gradation measuring process, causes measuring error.
Summary of the invention
The objective of the invention is to overcome the deficiencies in the prior art part, a kind of large range high precision fast laser ranging method and device based on the multiple frequency synchronous modulation is provided.The present invention has mainly carried out following improvement on the basis of existing multifrequency modulation technique: (1) replaces original multi-channel electronic switch unit at transmitter unit is multiple-frequency signal characteristic precompensation weighted sum processing unit; (2) replacing original multi-channel electronic switch unit at receiving element is that facies unit is surveyed in the synchronous bandpass filtering frequency-selecting of multichannel.Thereby become existing multifrequency asynchronous serial modulation distance measurement mode and be parallel synchronous modulation distance measurement mode, make that multifrequency modulation range finding is carried out synchronously, promptly obtain the distance measurement value of each modulation frequency at synchronization, total range finding time does not increase with the increase of modulation frequency number, realized on the one hand on the basis that guarantees measuring accuracy and wide range, target range being measured fast, adopted the multifrequency gradation to measure the range error that causes because of the target location variation when having avoided on the other hand moving target find range.
The present invention also provides a kind of large range high precision fast laser ranging device based on the multiple frequency synchronous modulation on the basis of above-mentioned measuring method.
Technical solution of the present invention is: a kind of multiple frequency synchronous modulated laser distance-finding method, and this method may further comprise the steps:
(1) adopts multiple modulation frequency f
0, f
1, f
2... f
nTarget is found range, and the method that modulation frequency adopts direct modulation frequency to select is got f
0=mf
1=mf
2=...=mf
n, distance accuracy Δ D then
0=m Δ D
1=m Δ D
2=...=m Δ D
n, ranging D
0=1/mD
1=1/mD
2=...=1/mD
n, the m value is 100 to 1000;
(2) according to above-mentioned modulation frequency f
0, f
1, f
2... f
nChoose sinusoidal signal and carry out the synthetic processing of weighted sum, obtain
Wherein: E
tBe final synthetic modulation signal, A is the sinusoidal signal amplitude,
Be the initial phase of sinusoidal signal, adopt this signal that laser power is modulated then and target is implemented range finding;
(3) obtaining electric signal through the heliogram of target reflection behind photoelectric switching circuit is:
Wherein: k
iBe the conversion gain that receiving circuit to frequency is, φ
iFor modulating frequency is f
iThe phase delay that behind target reflection, produces of light signal, treatment circuit is to signal E
rAdopt the frequency-selecting of multidiameter delay bandpass filtering to handle and obtain each component of signal, record each signal and the phase delay φ that transmits simultaneously
i, and then can try to achieve the range finding result of each modulation frequency simultaneously
Can try to achieve final range finding D as a result by Data Fusion at last.
Also adopted the characteristic precompensation in the synthetic processing of weighted sum, the modulation signal after the compensation is
Corresponding received signal is
α
iFor being f to frequency at photoelectric receiving system
iThe antidamping characteristic precompensation factor set of the frequency attenuation characteristic of modulated light signal, α
iValue should make α
iK
i=C, C are constant, i.e. the receiving system gain identical to the light signal generating of each modulation frequency in the heliogram.
The large range high precision fast laser ranging device of the multiple frequency synchronous modulation that said method uses, comprise multiple-frequency signal generating unit, laser instrument, laser power modulation driver element, Laser emission camera lens, laser pick-off camera lens, measuring light photodetector, measuring light photoelectric switching circuit, reference light photodetector, reference light photoelectric switching circuit, data fusion metrics calculation unit, comprise that also multiple-frequency signal synthesis unit, spectroscope, the logical frequency selecting and filter unit of multichannel band, multichannel are with the pacing facies unit;
The multiple-frequency signal generating unit produces the multichannel sinusoidal signal of corresponding frequencies according to selected modulation frequency, affacting the synchronous modulation unit after synthetic processing of this multiple signals process multiple-frequency signal synthesis unit modulates the power of laser instrument, laser beam after the modulation is launched to spectroscope by the Laser emission camera lens, through behind the spectroscope, reflected light forms measuring beam directive measured target, measuring beam is through being received after convert the measurement electric signal to by the measuring light photoelectric switching circuit behind the measuring light photodetector by the laser pick-off camera lens behind the target reflection, transmitted light forms reference light directive reference light photodetector and form reference electrical signal behind the reference light photoelectric switching circuit, measure electric signal and reference electrical signal and give the phase differential of the generation after there emerged a modulation frequency process target reflection with the pacing facies unit by multichannel after with logical frequency selecting and filter unit, the synthetic computing unit of distance synthesizes the phase differential that records handles the result that finally found range.
The present invention has following characteristics and good result:
The method that existing multifrequency modulated laser ranging technology all adopts timesharing gating modulation signal that laser power is modulated and then implemented to find range, the increase of the range finding time of the method with modulation frequency increases, be difficult to obtain the real time distance result when moving target is found range, and then cause range error.The present invention proposes multiple frequency synchronous modulated laser distance-finding method, promptly the synthetic back of multifrequency modulation signal is modulated laser power, when receiving, adopted the mode of surveying mutually with the synchronous bandpass filtering frequency-selecting of the corresponding multichannel of this modulator approach to carry out signal Processing simultaneously at laser emission element.Adopt this method can obtain the range finding result of each modulation frequency in the multifrequency modulation range finding at synchronization, and then obtain final distance measurement value, guaranteed range finding speed and real-time, this is one of innovative point of difference prior art;
The present invention has also proposed the multifrequency modulation signal is carried out the synthetic disposal route of characteristic precompensation weighted sum at the multiple frequency synchronous modulated laser distance-finding method that proposes, the characteristic precompensation of modulation signal is handled the optical power signals that the modulation frequency that makes the photoelectricity receiving element differ greatly to multifrequency phase modulation method laser ranging medium frequency modulates produce identical gain, avoided frequency attenuation characteristic because of the photoelectricity receiving element make the low frequency modulations light signal when receiving, produce saturated high frequency modulated light signal when receiving because of the too big signal to noise ratio (S/N ratio) of decay reduces, this be the difference prior art innovative point two.
Introduce multiple frequency synchronous modulation large range high precision fast laser ranging method and the device that the present invention proposes in detail below in conjunction with accompanying drawing.
Description of drawings
Fig. 1 is a multifrequency phase modulation method laser distance measuring principle block diagram used in the prior art
Fig. 2 is a multiple frequency synchronous phase modulation method laser ranging system synoptic diagram of the present invention
Fig. 3 is a multiple frequency synchronous modulating characteristic precompensation method synoptic diagram of the present invention
Fig. 4 is a characteristic precompensation factor establishing method synoptic diagram of the present invention
Fig. 5 is that the phase synoptic diagram is surveyed in the synchronous bandpass filtering frequency-selecting of multichannel of the present invention
Fig. 6 is a double frequency synchronous modulation phase type laser ranging system synoptic diagram provided by the invention
Fig. 7 receives structural representation for the coaxial Laser emission among the present invention
Fig. 8 a realizes reference light and measuring light light beam beam splitting synoptic diagram for adopting Amici prism 36 among the present invention
Fig. 8 b puts hole catoptron 37 realization reference light and measuring light light beam beam splitting synoptic diagram for adopting among the present invention
Fig. 8 c is hole catoptron 37 synoptic diagram of putting of the present invention
Embodiment
Multiple frequency synchronous modulation large range high precision fast laser ranging method
Fig. 3 has provided the precompensation weighting that the multifrequency modulation signal is carried out that the present invention taked and has synthesized synchronous modulation is carried out in the processing back to laser power synoptic diagram.
At first on the contradiction that solves Laser Range Finding Based on Phase measuring accuracy and range, adopt the multifrequency modulator approach, promptly adopt multiple modulating frequency (modulation frequency) f
0, f
1, f
2... f
nTarget is found range.The method that modulation frequency adopts direct modulation frequency to select, i.e. f
0=mf
1=mf
2=...=mf
nThe m value can from 100 to 1000 according to the difference of phase-measurement accuracy, and representative value is 100.Then by multiple-frequency signal generating unit 4 according to modulation frequency f
0, f
1, f
2... f
nProduce the sinusoidal signal of corresponding frequencies
Wherein A is a signal amplitude,
Be signal initial phase, i=0...n.
This sinusoidal signal is provided with unit 18 back amplitudes through precompensation factor and according to the difference of compensating factor corresponding change takes place, promptly
α wherein
iBe the precompensation factor, i=0...n.
The effect of multiple-frequency signal synthesis unit 10 is that each modulation frequency signal is synthesized, and makes each modulation frequency signal to affact simultaneously on the laser instrument, promptly realizes the multiple frequency synchronous modulation.Signal after synthetic is
This signal is implemented the multiple frequency synchronous modulation through 2 pairs of laser instruments of laser power modulation driver element 1.Fig. 4 has provided the establishing method of the characteristic precompensation factor.
In the laser ranging of multifrequency phase modulation formula, just need to improve the frequency of accurate measurement chi in order to improve distance accuracy, in order to increase the frequency that range need reduce the bigness scale chi, the modulation signal bandwidth is very wide when so realizing wide range and precision distance measurement, generally from several KHz to tens megahertzes, and photoelectric detective circuit all has certain bandwidth, usually to high-frequency signal generation decay in various degree, the high more decay of frequency is big more, and its characteristic is shown in curve among Fig. 4 21.Power to laser instrument among the present invention has adopted the multiple frequency synchronous modulation, if the modulation signal amplitude of corresponding modulation frequency is identical, when setting photoelectric switching circuit gain G guarantees that low frequency (bigness scale chi frequency) becomes sub-signal not produce saturation distortion, high frequency (accurate measurement chi frequency) becomes sub-signal to reduce because of the decay signal to noise ratio (S/N ratio), and then makes measuring accuracy reduce; When setting photoelectric switching circuit gain G guaranteed that high frequency (accurate measurement chi frequency) becomes sub-signal to satisfy the certain amplitude requirement, low frequency signal then can produce saturation distortion, caused and surveyed the phase error.
For this reason, the present invention proposes and adopt the characteristic precompensation method to solve the problems referred to above, the basic thought of characteristic precompensation is in the laser power modulation unit amplitude of each frequency component of multifrequency modulation signal to be carried out certain adjustment according to the frequency characteristic of photoelectricity receiving circuit, makes the photoelectricity receiving circuit produce identical gain to the laser modulation signal of each frequency component.Curve 21 is the frequency characteristic of photoelectricity receiving circuit among Fig. 4, and it is to modulation frequency f
0, f
1, f
2... f
nGain be k
0, k
1, k
2... k
nIn order to make light signal generating the identical gain C as straight line 20 shown in of photoelectricity receiving circuit to each modulation frequency, make curve 19 in the drawings, this curve and curve 21 then can obtain the precompensation factor-alpha of corresponding modulation frequency about straight line 20 symmetries
0, α
1, α
2... α
n, this factor makes α
iK
i=C, i=0,1...n.
Fig. 5 has provided the synchronous bandpass filtering frequency-selecting of multichannel and has surveyed the phase implementation method.
Emission of lasering beam through the distance measuring signal that the heliogram behind the target reflection obtains behind measuring light photodetector 6 and measuring light photoelectric switching circuit 7 is
Wherein: k
iFor receiving circuit is f to frequency
iThe conversion gain of modulated light signal, φ
iFor modulating frequency is f
iThe phase delay that behind target reflection, produces of light signal, α
iValue should make α
iK
i=C, C are constant.And be through the reference signal that reference light photodetector 13 and reference light photoelectric switching circuit 14 obtain
Wherein: β
iPhase delay for interior light path generation.
In order to record distance measuring signal E simultaneously
rWith reference signal E '
rIn the phase differential of each frequency component, the present invention has adopted the synchronous bandpass filtering frequency-selecting of multichannel to survey phase, promptly to distance measuring signal E
rWith reference signal E '
rIn each modulation frequency set the logical frequency selecting and filter unit 15 of multichannel band, provide the phase difference of each modulation frequency correspondence then simultaneously with pacing facies unit 16 by multichannel
i-β
i, i=0,1...n.At last by data fusion metrics calculation unit 17 to final range finding result, and by 22 demonstrations of distance display unit.
Adopt said method, can obtain the range finding result of each modulation frequency in the multifrequency modulation range finding and then obtain final distance measurement value at synchronization, can satisfy simultaneously and improved the real-time that range finding speed has guaranteed range finding on the basis of range and accuracy requirement characteristics not losing the laser ranging of multifrequency phase modulation method.
Multiple frequency synchronous phase modulation formula laser ranging system
Multiple frequency synchronous phase modulation formula laser ranging system is mainly by multiple-frequency signal generating unit 4, multiple-frequency signal synthesis unit 10, laser power modulation driver element 2, laser instrument 1, Laser emission camera lens 11, and laser pick-off camera lens 5, spectroscope 12, measuring light photodetector 6, measuring light photoelectric switching circuit 7, reference light photodetector 13, reference light photoelectric switching circuit 14, the logical frequency selecting and filter unit 15 of multichannel band, multichannel are formed with pacing facies unit 16, data fusion metrics calculation unit 17.
Multiple-frequency signal generating unit 4 is according to selected modulation frequency f
0, f
1, f
2... f
nProduce the sinusoidal signal of corresponding frequencies, the power that affacts 2 pairs of laser instruments 1 of laser power modulation driver element behind this signal process multiple-frequency signal synthesis unit 10 is modulated, laser beam after the modulation is launched to spectroscope 12 by Laser emission camera lens 11, through behind the spectroscope, reflected light forms measuring beam directive measured target, measuring beam is received after measuring light photodetector 6 backs convert the measurement electric signal to by measuring light photoelectric switching circuit 7 by laser pick-off camera lens 5 behind target reflection, transmitted light forms reference light directive reference light photodetector 13 and form reference electrical signal behind reference light photoelectric switching circuit 14, measure electric signal and reference electrical signal and given with pacing facies unit 16 by multichannel through the logical frequency selecting and filter unit 15 of multichannel band back and there emerged a the phase differential of modulation frequency through the generation behind the target reflection, data fusion metrics calculation unit 17 is synthesized the processing result that finally found range with the phase differential that records.
Embodiment 1
Double frequency synchronous modulation phase type laser ranging system
As shown in Figure 6, this device is mainly by semiconductor laser 23, Laser emission camera lens 11, spectroscope 12, plus lens 29, reference light photodetector (PIN) 13, laser pick-off camera lens 5, measuring light photodetector (APD) 6, measuring light photoelectric switching circuit 7, reference light photoelectric switching circuit 14, laser power modulation driver element 2, two-frequency signal characteristic precompensation weighted sum processing unit 24, signal generating unit 25 and 26, high-frequency band pass filter unit 31 and 34, low-frequency band pass filter unit 33 and 36, high frequency mixing unit 37 and 39, smart local oscillator and thick local oscillator generation unit 32 and 35, low frequency mixing unit 38 and 40, low- pass filter unit 41 and 42, low- pass filter unit 43 and 44, differ measuring unit 45 and 46, microprocessor unit 47, distance display unit 22 constitutes.
In order to obtain the processing mode that high-precision this device of phase difference measurements has adopted heterodyne, be about to accurate measurement signal E
r(f
0) and E '
r(f
0) the signal E (f that produces with smart local oscillator generation unit
L0) carry out mixing and low-pass filtering; Bigness scale signal E
r(f
1) and E '
r(f
1) the signal E (f that produces with thick local oscillator generation unit
L1) carry out mixing and low-pass filtering.Wherein mixing adopts analog multiplier to realize, low-pass filtering adopts second order VCO source type low-pass filter, and local oscillation signal adopts the Direct Digital synthetic technology to produce smart local oscillation signal f
L0Get 7.502MHz, thick local oscillation signal f
L1Get 77KHz.Measuring-signal and reference signal are 2KHz through the intermediate-freuqncy signal frequency after the Frequency mixing processing.
Enter through low- pass filter 41 and 42 signal and to differ measuring unit 45 and obtain differing φ
0, enter through low- pass filter 43 and 44 signal and to differ measuring unit 46 and obtain differing φ
147 pairs of two-way phase difference signal of microprocessor unit are carried out the distance calculation line data fusion treatment of going forward side by side and are finally obtained the result that finds range, and are shown on the display unit 22.The phase difference measurements adopts synchronous digital to survey phase, and phase-measurement accuracy is 360 °/20000, theoretical distance accuracy 1mm.Because microprocessor unit 47 can obtain surveying facies unit 45 and 46 survey result mutually simultaneously, so can carry out data fusion fast and then provide final range finding result.
In this example, laser beam transmits and receives the unit and adopts close coupled type optical texture shown in Figure 7.In this structure, the laser beam that semiconductor laser 23 sends forms light beam 47 and exposes to spectroscope 12 along optical axis 27 behind Laser emission camera lens 11, spectroscope 12 is positioned at the intersection point place of optical axis 27 and 28, and all is 45 ° of angles with optical axis 27 and 28, and optical axis 27 is vertical mutually with 28.Light beam 47 is behind spectroscope 12, and to measured target, transmitted light beam 51 is also converged on the photosurface of reference light photodetector 13 to plus lens 29 along optical axis 27 irradiations folded light beam 48 along optical axis 28 irradiations.Laser beam 48 is returned along optical axis 28 after cooperation target (retroreflector) reflection, and is converged to by laser pick-off camera lens 5 on the photosurface of measuring light photodetector 6.Laser beam transmits and receives and adopts this structure to guarantee that heliogram converges on the optical axis at measuring light photodetector 6 places all the time, has eliminated from the axle optical texture and produce the blind area that BEAM SQUINT photodetector place optical axis causes when target range is advanced.This coaxial optical texture also has the advantage of compact conformation simultaneously.
Wherein, spectroscope 12 can adopt Amici prism 50 to realize that light path is shown in Fig. 8 a.Wherein reflectivity is desirable 80%～90%, transmissivity desirable 20%～10%.
Embodiment 2
Three frequency synchronous modulation phase type laser ranging systems
As shown in Figure 6, this example has increased by one road modulation signal at transmitter unit on the basis of double frequency synchronous modulation phase type laser ranging system, i.e. bigness scale chi frequency f
2, f
2Get 750Hz, this signal adopts the Direct Digital synthetic technology to realize equally; Increased by one road bandpass filtering frequency-selecting at receiving element accordingly and surveyed circuitry phase, wherein the bandpass filter centre frequency is got 750Hz, and-three dB bandwidth is 100Hz; Differ measuring unit and be adjusted into three phases of synchronous digital survey frequently.Other unit and the principle of work of this example are identical with example 1.The theoretical ranging of this distance measuring equipment is 200Km.
Below in conjunction with the accompanying drawings the specific embodiment of the present invention is described; but these explanations can not be understood that to have limited scope of the present invention; protection scope of the present invention is limited by the claims of enclosing, and any change of carrying out on claim of the present invention basis all is protection scope of the present invention.
Claims (10)
1. multiple frequency synchronous modulated laser distance-finding method is characterized in that this method may further comprise the steps:
(1) adopts multiple modulation frequency f
0, f
1, f
2... f
nTarget is found range, and the method that modulation frequency adopts direct modulation frequency to select is got f
0=mf
1=mf
2=...=mf
n, distance accuracy Δ D then
0=m Δ D
1=m Δ D
2=...=m Δ D
n, ranging D
0=1/mD
1=1/mD
2=...=1/mD
n, the m value is 100 to 1000;
(2) according to above-mentioned modulation frequency f
0, f
1, f
2... f
nChoose sinusoidal signal and carry out the synthetic processing of weighted sum, obtain
Wherein: E
tBe final synthetic modulation signal, A is the sinusoidal signal amplitude,
Be the initial phase of sinusoidal signal, adopt this signal that laser power is modulated then and target is implemented range finding;
(3) obtaining electric signal through the heliogram of target reflection behind photoelectric switching circuit is:
Wherein: k
iBe the conversion gain that receiving circuit to frequency is, φ
iFor modulating frequency is f
iThe phase delay that behind target reflection, produces of light signal, treatment circuit is to signal E
rAdopt the frequency-selecting of multidiameter delay bandpass filtering to handle and obtain each component of signal, record each signal and the phase delay φ that transmits simultaneously
i, and then try to achieve the range finding result of each modulation frequency simultaneously
I=0,1,2...n tries to achieve final range finding D as a result by Data Fusion at last.
2. method according to claim 1 is characterized in that also having adopted the characteristic precompensation in the synthetic processing of weighted sum, and the modulation signal after the compensation is
Corresponding received signal is
α
iFor being f to frequency at photoelectric receiving system
iThe antidamping characteristic precompensation factor set of the frequency attenuation characteristic of modulated light signal, α
iValue should make α
iK
i=C, C are constant, i.e. the receiving system gain identical to the light signal generating of each modulation frequency in the heliogram.
3. method according to claim 1 and 2 is characterized in that the m value is 100.
4. the multiple frequency synchronous modulated laser distance measuring equipment that uses of the described method of a claim 1, comprise multiple-frequency signal generating unit, laser instrument, laser power modulation driver element, Laser emission camera lens, laser pick-off camera lens, measuring light photodetector, measuring light photoelectric switching circuit, reference light photodetector, reference light photoelectric switching circuit, data fusion metrics calculation unit, it is characterized in that also comprising that multiple-frequency signal synthesis unit, spectroscope, the logical frequency selecting and filter unit of multichannel band, multichannel are with the pacing facies unit;
The multiple-frequency signal generating unit produces the multichannel sinusoidal signal of corresponding frequencies according to selected modulation frequency, affacting the synchronous modulation unit after synthetic processing of this multiple signals process multiple-frequency signal synthesis unit modulates the power of laser instrument, laser beam after the modulation is launched to spectroscope by the Laser emission camera lens, through behind the spectroscope, reflected light forms measuring beam directive measured target, measuring beam is through being received after convert the measurement electric signal to by the measuring light photoelectric switching circuit behind the measuring light photodetector by the laser pick-off camera lens behind the target reflection, transmitted light forms reference light directive reference light photodetector and form reference electrical signal behind the reference light photoelectric switching circuit, measure electric signal and reference electrical signal and give the phase differential of the generation after there emerged a modulation frequency process target reflection with the pacing facies unit by multichannel after with logical frequency selecting and filter unit, the synthetic computing unit of distance synthesizes the phase differential that records handles the result that finally found range.
5. device according to claim 4 is characterized in that said multiple-frequency signal generating unit is two-frequency signal generating unit or three signal generating unit frequently.
6. device according to claim 4 is characterized in that said laser power modulation driver element is that the signal that adopts the multiple-frequency signal synthesis unit to provide is modulated the driving of laser power, and its modulation system is internal modulation mode or external modulation mode.
7. device according to claim 4 is characterized in that said multichannel band leads to frequency selecting and filter unit and is made up of side by side the multichannel bandpass filter.
8. device according to claim 4, its feature have adopted emission to receive coaxial optical texture being made of the laser transmitting-receiving antenna said Laser emission camera lens, laser instrument, laser pick-off camera lens and spectroscope.
9. device according to claim 4 is characterized in that said spectroscope has adopted Amici prism beam split mode, and the transmitance of Amici prism is 10%～20%, and reflectivity is 90%～80%.
10. device according to claim 4, it is characterized in that said spectroscope has adopted the beam split mode of putting the hole catoptron, the catoptron center is provided with light hole, the ratio of the area of light hole and catoptron reflector segment area is 10%～20%, and the shape of catoptron and light hole is circular, square or centrosymmetric polygon here.
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| CN101141200B (en) * | 2007-10-15 | 2010-08-04 | 哈尔滨工业大学 | Multi-frequency phase modulation based multi-wavelength source generating apparatus |
| CN101387700B (en) * | 2008-10-12 | 2011-09-21 | 北京大学 | Data fusing method and system based on multi-laser scanner |
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| CN101806897B (en) * | 2009-02-17 | 2012-05-30 | 南京德朔实业有限公司 | Electro-optical distance measurement method and device thereof |
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