CN103018745A - Distance measuring method and system - Google Patents
Distance measuring method and system Download PDFInfo
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- CN103018745A CN103018745A CN2011102816542A CN201110281654A CN103018745A CN 103018745 A CN103018745 A CN 103018745A CN 2011102816542 A CN2011102816542 A CN 2011102816542A CN 201110281654 A CN201110281654 A CN 201110281654A CN 103018745 A CN103018745 A CN 103018745A
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Abstract
The invention discloses a distance measuring method and a distance measuring system. A light speed value and a time value of arriving and departing from an object to be detected by a light signal are used for carrying out calculation of a distance, and a frequency which is synchronous with transmitting/receiving of the light signal is used for shielding to obtain a period quantity of a reference signal under the shielding of the frequency to convert one time value; meanwhile, the time value is revised by a plurality of phase displacement signals generated based on the reference signal and an error is further reduced along the increasing of the quantity of the phase displacement signals, so as to obtain the accurate time value of arriving and departing from the object to be detected by the light signal; and the distance measuring method and the distance measuring system have the advantages of high measuring speed and small circuit area occupied by the measuring system.
Description
Technical field
The present invention is about a kind of distance measuring method and system, more particularly about a kind of more accurate distance measuring method and system.
Background technology
Distance measuring method and system are divided into transmitting-receiving and measuring time value two parts of light signal usually, and recycling optical speed value and the time value that obtains are carried out distance operation, with obtain and determinand between distance value.The measurement of time is to come and go determinand time institute elapsed time for measuring light signal, can estimate distance value based on this time and optical speed value, measuring time value then normally utilizes a base frequency signal (or being defined as the known time) to converse light signal institute's elapsed time between transmitting-receiving.
The measuring time value method is when utilizing this light signal between receiving and sending out, the default frequency value of the cycle times of this base frequency signal and this base frequency signal obtains time value, and the precision of obtaining the cycle times of this base frequency signal just affects the accuracy of obtained time value.
The practice that obtains this base frequency signal period number of times generally is to utilize counting method to carry out, in a gate time namely light signal receipts and the time of sending out and the base frequency signal in gate time is carried out the counting of amount of cycles.Yet because the amount of cycles of the base frequency signal in gate time can not be round values usually, therefore, this kind mode causes error in beginning and the end of gate time easily, such as: count less the half period number or count half period number etc. more.
Summary of the invention
A purpose of the present invention is to improve instruction cycle in the distance measuring process and the accuracy of measurement.
Another object of the present invention is to reduce the circuit area occupied and reduce power consumption.
For reaching above-mentioned purpose and other purposes, the present invention proposes a kind of distance measuring method, it utilizes the optical speed value of light signal and the time value that this obtained light signal of measuring time value method comes and goes, carry out and determinand between distance operation, it is characterized in that this measuring time value method comprises: provide a reference signal; Based on a plurality of phase displacement signals of this reference signal generation tool same frequency, be interval one stationary phase between these phase displacement signals; Set a frequency masks, it is that one when originating in this light signal of emission transmits, and ends at a reception signal of this light signal that receives reflection; Initial sequential point to this reference signal in this frequency masks occurs to count the times N d1 that the second triggering states occur these phase displacement signals in the time interval of the first triggering state; In the time interval of this frequency masks, based on this first triggering state, count the cycle times Nb that this reference signal occurs; Termination sequential point to this reference signal in this frequency masks occurs to count the times N d2 that the second triggering states occur these phase displacement signals in the time interval of the first triggering state; And comply with rear formula and obtain the round time value t of this light signal, t=(Nb/Fb)+[Nd1/ (Fb/M)]-[Nd2/ (Fb/M)], wherein, Fb is the frequency of this reference signal, M is the number of these phase displacement signals, M＞=2.
For reaching above-mentioned purpose and other purposes, the present invention proposes a kind of distance measuring system, it comprises: a light signal generating unit, it is used for emission one light signal and is received from this light signal that a determinand reflects, and transmits with the corresponding generation one of reception and a reception signal based on the emission of this light signal; One signal input part, it is used for receiving this and transmits and this reception signal; One distance measuring device, it connects this signal input part and transmits and this reception signal to receive this, and be the reference signal of Fb for generation of frequency values, and produce tool same frequency and M phase displacement signal of interval one stationary phase each other based on this reference signal, and for generation of a frequency masks that originates in this and transmit and end at this reception signal, and be used in initial sequential point to this reference signal of this frequency masks the times N d1 that the second triggering state occurs first these phase displacement signals of time interval inside counting that trigger state occuring, and for the cycle times Nb that in the time interval of this frequency masks, occurs based on this this reference signal of the first triggering Count of Status, and the times N d2 that is used for occuring in termination sequential point to this reference signal of this frequency masks these phase displacement signals generation second triggering states of time interval inside counting of the first triggering state, and be used for these numerical value of output Fb, M, Nb, Nd1, and Nd2; And an arithmetic unit, it connects this distance measuring device, is used for receiving these numerical value and carries out computing comes and goes this determinand to obtain this light signal time value t according to following formula, and be used for according to this time value t and optical speed value c (3 * 10
8M/s) carry out and determinand between distance operation, t=(Nb/Fb)+[Nd1/ (Fb/M)]-[Nd2/ (Fb/M)], wherein, M＞=2.
In one embodiment, this distance measuring device comprises: a fundamental frequency generation unit, and it is for generation of a fundamental frequency signal; One frequency multiplication unit, it connects this fundamental frequency generation unit, and being used for this fundamental frequency signal frequency multiplication is this reference signal; An and programmable gate array, it connects this signal input part and transmits and this reception signal to receive this, and connect this frequency multiplication unit receiving this reference signal, and for generation of these numerical value M, Nb, Nd1, and Nd2 and export these numerical value Fb, M, Nb, Nd1, and Nd2.
In one embodiment, this arithmetic unit can be one of them in the two of a control module and a computer installation.
In one embodiment, this first triggering state can be upper limb and triggers state and lower edge and trigger in the two of state one of them; This second triggering state can be upper limb and triggers state and lower edge and trigger in the two of state one of them.
The number of these phase displacement signals that produce in one embodiment, can be 4 or 8.
In one embodiment, the frequency Fb of this reference signal can directly be substituted by a default value.
Thus, the error that distance measuring method of the present invention and system's utilization can produce when the leggy processing mode has been eliminated measuring time value fast and accurately, and along with the generation quantity of phase displacement signal multiplication accuracy of measurement, and can reach small electric road area occupied and reduce the effect of power consumption.
Description of drawings
Fig. 1 is the time sequences figure of the distance measuring method in one embodiment of the invention.
Fig. 2 is the operation workflow figure of the distance measuring method in one embodiment of the invention.
Fig. 3 is the functional block diagram of the distance measuring system in one embodiment of the invention.
Among the figure:
100, the distance measuring system;
105, the light signal generating unit;
110, signal input part;
120, the distance measuring device;
121, the fundamental frequency generation unit;
123, the frequency multiplication unit;
125, programmable gate array;
130, arithmetic unit;
Fb, reference signal and frequency thereof;
Mk, frequency masks;
Nb, the cycle times of reference signal;
Nd1, second triggers the number of times of state;
Nd2, second triggers the number of times of state;
Fb-p1 ~ 8, phase displacement signal;
SS transmits;
ES receives signal;
S101 ~ 107, step;
T, actual institute elapsed-time standards;
Tb, the frequency masks time;
Td1, the front end error time;
Td2, the rear end error time.
Embodiment
For fully understanding purpose of the present invention, feature and effect, by following specific embodiment, and cooperate appended graphicly, the present invention is described in detail, illustrate as after:
Each step described in the specific embodiment of distance measuring method of the present invention is except specializing, and it can mutually exchange all the other steps and be not to comply with the explanation order of arranging to decide the sequencing that step is carried out; In addition, described in the specific embodiment of distance measuring of the present invention system ' connecting ' one word, it is non-limiting in direct connection, and the centre also can connect other unit.Moreover, described ' first triggering state ', it comprises ' second triggering state ' one word upper limb and triggers state and lower edge and trigger in the two of state one of them, the first triggering state and the second not mutual exclusion of triggering state, that is, the first triggering state and the second triggering state can trigger state or trigger state for lower edge simultaneously for upper limb simultaneously.
The course that comes and goes between determinand and measurement system based on light signal in the embodiments of the invention is carried out the measurement of time quantum measured value, and obtain the time quantum measured value by leggy facture and predetermined formula, at last based on the optical speed value of light signal and this time quantum measured value is obtained and determinand between the distance measurements measured value.
At first see also Fig. 1, be the time sequences figure of the present invention's distance measuring method in one embodiment.Be used as example with 8 phase displacement signals in this embodiment, be familiar with this operator and will be appreciated that, as long as have phase displacement signal more than 2 can eliminate the measuring time value error and then promote the accuracy of time value.
Distance measuring method in embodiments of the present invention can comprise following steps:
As shown in Figure 1, in the distance measuring process of determinand, the light signal generating unit is at this light signal of emission and when receiving from light signal that determinand reflects, can correspondingly produce the SS and that transmits and receive signal ES.Measuring time value method in the embodiment of the invention can provide first a reference signal Fb before measuring the action beginning, and produce the multistage phase displacement signal Fb-p1 ~ Fb-p8 of tool same frequency, interval one stationary phase between every single order phase displacement signal Fb-p1 ~ Fb-p8 based on this reference signal.
This reference signal Fb is used as the frequency on a basis.Phase displacement signal then produces from this reference signal Fb, usually can utilize numerical frequency manager (DCM) in the programmable gate array (FPGA) to come the phase shift of settling signal.With present embodiment, have 8 phase displacement signal Fb-p1 ~ Fb-p8, therefore can utilize two groups numerical frequency manager to reach, wherein, set of number frequency management device can resolve into 4 phase displacement signals with reference to signal Fb.Yet being familiar with this operator will be appreciated that, even only use one group numerical frequency manager, the user still can optionally close 4 phase shift micromotions wherein, namely, only use one group the lower of numerical frequency manager still can resolve into 2 or 3 phase displacement signals with reference to signal Fb, therefore, the user can be according to demand and the utilization of the numerical frequency manager of arranging in pairs or groups select required phase displacement signal quantity.Then be by the numerical frequency manager phase places etc. of 360 degree to be given each phase displacement signal as for the interval between phase displacement signal, for example: the quantity of phase displacement signal is M, and then the interval phase place is 360/ (M-1).
Then be to set a frequency masks mk, this SS that transmits when it originates in this light signal of emission ends at this reception signal ES of this light signal that receives reflection.That is, this frequency masks mk can trigger synchronously with SS signal and ES signal, comes and goes the time of experiencing between determinand and measurement system so that the measuring time value interval is equal to this light signal.SS signal and the ES signal that triggers with upper limb shown in Figure 1 done example, and tool knows that usually the knowledgeable can recognize in the affiliated technical field, and this SS signal and ES signal also can represent the transmission time point of this light signal and receive time point by lower edge triggering state.
When frequency masks mk one was set initial value, the measurement of time action launched immediately.Please refer to Fig. 1, because reference signal Fb is not synchronous with frequency masks mk, therefore in the cycle times Nb of the reference signal Fb that is measured, its elapsed time is actually incongruent with the scope of frequency masks mk, and this namely can cause front end error and rear end error.
Therefore, front end and the rear end error namely utilizing these phase displacement signals to eliminate in the embodiments of the invention to cause in the measuring time value process.
In the front end error, its initial sequential in frequency masks mk is put to reference signal Fb and is occured to count the times N d1 that the second triggering state (upper limb or lower edge trigger state) occurs these phase displacement signals Fb-p1 ~ Fb-p8 in the time interval of the first triggering state.
In the error of rear end, its termination sequential at frequency masks mk is put to reference signal Fb and is occured to count the times N d2 that the second triggering state (upper limb or lower edge trigger state) occurs these phase displacement signals Fb-p1 ~ Fb-p8 in the time interval of the first triggering state.
It refers to described ' these phase displacement signals Fb-p1 ~ Fb-p8 occur the second triggering state ' second when triggering state, just must select equally upper limb to trigger state as this second triggering state as this in the error burst of rear end when selecting upper limb to trigger state in the front end error burst; Otherwise, when selecting lower edge to trigger state as this second triggering state in the front end error burst, in the error burst of rear end, just must select equally lower edge triggering state as this second triggering state.With the example of Fig. 1, it selects upper limb to trigger state as this second triggering state, and therefore, the count value of the Nd1 in Fig. 1 is ' 3', Nd2 be ' 5'.
As shown in Figure 1, it is " t " that light signal comes and goes the time of in fact experiencing between determinand and measurement system, and time value t can meet the computing of formula (1):
t＝tb＋td1－td2 (1)
Therefore, in follow-up calculating, the number of times of Nd1 and the number of times of Nd2 can be used for obtaining front end error time td1 and rear end error time td2, and then eliminate front end and rear end error.
Nb be reference signal Fb in the time interval of frequency masks mk, the cycle times that is measured based on the first triggering state; Fb also is used for representing the frequency values of reference signal Fb; M is the quantity of phase displacement signal.Wherein, described ' based on the first triggering state ', its counting basis that refers to the cycle times of reference signal Fb can be consistent with the terminal state of front end error time interval (td1), namely, the example of Fig. 1, the counting starting point of the cycle times of reference signal Fb is from the upper limb triggering and begins counting, but not begins to count the cycle times of reference signal Fb from the lower edge triggering; Otherwise, if the time interval of td1 is changed into: put when lower edge occuring trigger the time interval of state (the first triggering state) to reference signal Fb from the initial sequential of frequency shielding mk, the terminal state of front end error time interval (td1) namely becomes lower edge and triggers state, and the counting starting point of the cycle times of reference signal Fb namely need be changed into from the lower edge triggering as the counting basis.Therefore, by the relational expression of Time And Frequency and number of times as can be known, frequency masks time tb can be obtained by following formula (2):
tb＝(Nb/Fb) (2)
Front end error time td1 can be obtained by following formula (3):
td1＝[Nd1/(Fb/M)] (3)
Rear end error time td2 can be obtained by following formula (4):
td2＝[Nd2/(Fb/M)] (4)
Accordingly, the actual elapsed-time standards value t of institute can be obtained by following formula (5):
t＝(Nb/Fb)＋[Nd1/(Fb/M)]－[Nd2/(Fb/M)] (5)
Wherein, M is the number of these phase displacement signals, M＞=2, and the individual number system of these phase displacement signals that namely produce is at least 2.
Further, the quantity that also can be recognized phase displacement signal by formula (5) is more, the accuracy multiple that can promote is just higher, that is, the method among Fig. 1 embodiment of the present invention has promoted 8 times accuracy altogether at least compared to the method for not carrying out front end error and rear end error correction.The quantity of phase displacement signal is more, and just to be equivalent to the time interval less, can eliminate more tiny error.
Then see also Fig. 2, be the operation workflow figure of the distance measuring method in one embodiment of the invention.Please also refer to Fig. 1, except reference signal Fb and phase displacement signal Fb-p1 ~ Fb-p8 thereof provided in advance, the measurement of time partly was controlled by the measurement part of distance.The measurement part of time: (S101) provide reference signal Fb, and a plurality of phase displacement signal Fb-p1 ~ Fb-p8; (S102) then based on SS and ES signal sets frequency masks mk; Then, (S103) obtain front end error count value Nd1; Then, (S104) close frequency masks mk and obtain periodicity count value Nb; Then, (S105) obtain rear end error count value Nd2; Then, (S106) carry out the as a result computing of formula (5); At last, (S107) utilize time t and optical speed value c to carry out distance operation, can measure distance value (c * t).
Then see also Fig. 3, be the functional block diagram of the present invention distance measuring system in one embodiment.This distance measuring system 100 comprises: a light signal generating unit 105, a signal input part 110, a distance measuring device 120 and an arithmetic unit 130.
Light signal generating unit 105 is used for the utilizing emitted light signal and is received from this light signal of determinand reflection, and based on the emission of this light signal with receive corresponding generation transmit SS and reception signal ES.
Distance measuring device 120 is to connect signal input part 110 to receive this transmit SS and this reception signal ES, and distance measuring device 120 is for generation of lower column signal or numerical value: aforementioned reference signal Fb, M phase displacement signal of interval one stationary phase each other, originate in this SS and end at the frequency masks mk of this reception signal ES of transmitting, the times N d1 of the second triggering state occurs in these phase displacement signals in the front end error burst, the times N b of the first triggering state occurs in this reference signal Fb in this frequency masks mk, these phase displacement signals occur second and trigger the times N d2 of state in the error burst of rear end, and export these numerical value Fb, M, Nb, Nd1, and Nd2.
In one embodiment, this distance measuring device 120 can comprise: a fundamental frequency generation unit 121, a frequency multiplication unit 123, an and programmable gate array 125.Fundamental frequency generation unit 121 is for generation of a fundamental frequency signal.Normally utilize crystal oscillator to produce lower fundamental frequency, so can reduce cost, by the frequency multiplication unit 123 that connects this fundamental frequency generation unit 121 fundamental frequency is promoted again, with as this reference signal Fb.
Programmable gate array is known assembly, the system of distance measuring system of the embodiment of the invention utilizes its each logic module that includes to reach purpose of the present invention, and can use less logic module under the method for using in embodiments of the present invention, and need not select large-area programmable gate array chip, and then can reduce area that circuit takies and shorten product sizes.For instance, if the words that the calculation function of arithmetic unit is also included in the programmable gate array will significantly increase required logic module quantity, and then increase the circuit area occupied; That programmable gate array will reach identical calculation process just must be processed with logical course because of due to the structural design, though that the fast logic module demand of its speed becomes is huge; Though include use and calculation process at a high speed that the special programmable gate array of operating structure circuit can reach low logic module space, its unit price is too high.
Further, in order more to reduce error, the high precision that also can carry out the reference signal Fb that produces in advance measures, namely, in fact the frequency that produces for fear of fundamental frequency generator and frequency multiplier and the error that occurs different from the sign value that gives, the high-accuracy frequency-measuring instrument that can utilize resolution to be higher than reference signal Fb frequency comes in advance the reference signal Fb that produces on the module to be measured, and directly is stored in the arithmetic unit 130 as a default value with this measuring value.Like this so that in the measurement each time, the frequency values of reference signal Fb all can use this default value, and the parameter that can not select fundamental frequency generator and frequency multiplier on specification, to be indicated.
Comprehensively above-mentioned, the error of measuring time value has been eliminated in distance measuring method of the present invention and system's utilization fast and accurately leggy processing mode, and along with the generation quantity of phase displacement signal multiplication accuracy of measurement, be 8 times (corresponding 8 phase displacement signals) that error is dwindled with the present invention's embodiment, and then reach high-precision distance measuring, and the effect that reaches small electric road area occupied.
The present invention is open with preferred embodiment hereinbefore, so has the knack of the technology person and it should be understood that this embodiment only is used for describing the present invention, does not limit the scope of the invention and should not be read as.It should be noted that variation and the displacement of all and this embodiment equivalence all should be made as and be covered by in the category of the present invention.Therefore, protection scope of the present invention when with claim the person of being defined be as the criterion.
Claims (11)
1. distance measuring method, it utilizes the optical speed value of light signal and the time value that this obtained light signal of measuring time value method comes and goes, carry out and determinand between distance operation, it is characterized in that: this measuring time value method comprises:
One reference signal is provided;
Based on a plurality of phase displacement signals of this reference signal generation tool same frequency, be interval one stationary phase between these phase displacement signals;
Set a frequency masks, one when it originates in this light signal of emission transmits, and ends at a reception signal of this light signal that receives reflection;
Initial sequential point to this reference signal in this frequency masks occurs to count the times N d1 that the second triggering states occur these phase displacement signals in the time interval of the first triggering state;
In the time interval of this frequency masks, based on this first triggering state, count the cycle times Nb that this reference signal occurs;
Termination sequential point to this reference signal in this frequency masks occurs to count the times N d2 that the second triggering states occur these phase displacement signals in the time interval of the first triggering state; And
Obtain the round time value t of this light signal according to following formula,
t＝(Nb/Fb)＋[Nd1/(Fb/M)]－[Nd2/(Fb/M)]
Wherein, Fb is the frequency of this reference signal, and M is the number of these phase displacement signals, M＞=2.
2. the method for claim 1 is characterized in that: wherein this first triggering state is that upper limb triggers state and lower edge and triggers in the two of state one of them.
3. the method for claim 1 is characterized in that: wherein this second triggering state is that upper limb triggers state and lower edge and triggers in the two of state one of them.
4. the method for claim 1, it is characterized in that: wherein, the number of these phase displacement signals that produce is 4 or 8.
5. the method for claim 1 is characterized in that: wherein also comprise: the frequency Fb of this reference signal is substituted by a default value.
6. the method for claim 1, it is characterized in that: wherein the value of this stationary phase is 360/ (M-1).
7. distance measuring system, it is characterized in that: it comprises:
One light signal generating unit, it is used for emission one light signal and is received from this light signal that a determinand reflects, and transmits with the corresponding generation one of reception and a reception signal based on the emission of this light signal;
One signal input part, it is used for receiving this and transmits and this reception signal;
One distance measuring device, it connects this signal input part and transmits and this reception signal to receive this, and be the reference signal of Fb for generation of frequency values, and produce tool same frequency and M phase displacement signal of interval one stationary phase each other based on this reference signal, and for generation of a frequency masks that originates in this and transmit and terminate in this reception signal, and be used in initial sequential point to this reference signal of this frequency masks the times N d1 that the second triggering state occurs first these phase displacement signals of time interval inside counting that trigger state occuring, and for the cycle times Nb that in the time interval of this frequency masks, occurs based on this this reference signal of the first triggering Count of Status, and the times N d2 that is used for occuring in termination sequential point to this reference signal of this frequency masks these phase displacement signals generation second triggering states of time interval inside counting of the first triggering state, and be used for these numerical value of output Fb, M, Nb, Nd1, and Nd2; And
One arithmetic unit, it connects this distance measuring device, be used for to receive these numerical value and carry out computing comes and goes this determinand to obtain this light signal time value t according to following formula, and be used for according to this time value t and optical speed value c carries out and determinand between distance operation,
t＝(Nb/Fb)＋[Nd1/(Fb/M)]－[Nd2/(Fb/M)]
Wherein, M＞=2.
8. distance measuring as claimed in claim 7 system, it is characterized in that: wherein this distance measuring device comprises:
One fundamental frequency generation unit, it is for generation of a fundamental frequency signal;
One frequency multiplication unit, it connects this fundamental frequency generation unit, and being used for this fundamental frequency signal frequency multiplication is this reference signal; And
One programmable gate array, it connects this signal input part and transmits and this reception signal to receive this, and connect this frequency multiplication unit receiving this reference signal, and for generation of these numerical value M, Nb, Nd1, and Nd2 and export these numerical value Fb, M, Nb, Nd1, and Nd2.
9. such as the described distance measuring of claim 8 system, it is characterized in that: wherein this arithmetic unit system is used for this numerical value Fb is substituted by a default value.
10. such as the described distance measuring of claim 7 system, it is characterized in that: wherein this arithmetic unit is one of them in the two of a control module and a computer installation.
11. such as the described distance measuring of claim 7 system, it is characterized in that: wherein this first triggering state is that upper limb triggers state and lower edge and triggers in the two of state one of them; This second triggering state is that upper limb triggers state and lower edge and triggers in the two of state one of them.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103424748A (en) * | 2013-08-31 | 2013-12-04 | 王敏 | Photosensitive constant-current capacitance integration area array distance sensor |
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