WO2005031258A1 - Dispositif d'oscillation a reflexion d'ondes pulsees servant a la mesure de distance et procede associe - Google Patents

Dispositif d'oscillation a reflexion d'ondes pulsees servant a la mesure de distance et procede associe Download PDF

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Publication number
WO2005031258A1
WO2005031258A1 PCT/CN2004/001045 CN2004001045W WO2005031258A1 WO 2005031258 A1 WO2005031258 A1 WO 2005031258A1 CN 2004001045 W CN2004001045 W CN 2004001045W WO 2005031258 A1 WO2005031258 A1 WO 2005031258A1
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WO
WIPO (PCT)
Prior art keywords
pulse
reflection
ranging
distance
oscillation
Prior art date
Application number
PCT/CN2004/001045
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English (en)
Chinese (zh)
Inventor
Tzuihu Lee
Original Assignee
Tzuihu Lee
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Tzuihu Lee filed Critical Tzuihu Lee
Publication of WO2005031258A1 publication Critical patent/WO2005031258A1/fr

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Classifications

    • G—PHYSICS
    • 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
    • G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
    • G01S17/02—Systems using the reflection of electromagnetic waves other than radio waves
    • G01S17/06—Systems determining position data of a target
    • G01S17/08—Systems determining position data of a target for measuring distance only
    • G01S17/10—Systems determining position data of a target for measuring distance only using transmission of interrupted, pulse-modulated waves

Definitions

  • Pulse wave reflection oscillation device for ranging and method thereof
  • the present invention relates to a pulse wave reflection oscillation device and method for ranging. Background technique
  • the laser has the following optical properties: its spectral width is very narrow, it has a high degree of monochromaticity (monochromaticity); after a long distance of propagation, it can still maintain a small beam, with a high degree of directionality (compared to)
  • lasers have a high degree of coherence in space and time; lasers have high brightness because of their high power and very small solid angles.
  • the speed of light in a given medium is constant, it is possible to measure the round-trip propagation time of light between a reference point and a measured point. The distance between the target and the reference point is determined.
  • the commonly used laser ranging methods can be divided into two types: When the laser is modulated by a sine wave, this is the phase method. When the laser is modulated by a pulse wave, this is the pulse method.
  • Phase method ranging is to modulate the light wave in some form, then measure the phase difference between the transmitted wave and the reflected wave, and then calculate the distance from it; while pulse method ranging is to directly measure the time of flight of the light pulse to calculate the distance
  • phase method ranging or pulse method ranging in order to obtain high-precision distance measurement, the former must design a good phase meter and oscillating circuits that deal with two or more different frequencies; the latter must design high-precision
  • a time interval measurement circuit includes a variety of time interpolation techniques. The circuit design required by both is quite complicated and requires a high level of technology to achieve.
  • Figure 1 is a basic block diagram of phase ranging.
  • the laser is output after amplitude modulation and returns via the target.
  • the photodetector converts it into an electrical signal, which is then amplified by an amplifier and sent to a phase meter.
  • the reflected wave is formed by A phase difference will occur between the signal and the wave signal due to the propagation delay.
  • the phase difference is read by a phase meter and sent to the processor for calculation to obtain the size of the distance.
  • the modulation frequency is fAM
  • the modulation wavelength is ⁇ AM
  • the distance between the transmitting system and the target is R (the distance between the light traveling back and forth between the measurement ground and the target through 2R), and the resulting phase difference is ⁇
  • the signal is transmitted
  • the relationship between A (t), reflected signal B (t), and distance R can be expressed by the following formulas (1-1), (1-2), and (1-3):
  • the distance R to be measured can be obtained by the formula (1-4).
  • the distance R can be determined by both the length of the measuring ruler and the scale value (phase difference) read on the measuring ruler. Therefore, a phase meter has become an important device for such a ranging method.
  • the phase meter can only measure the relative phase difference of less than one period between the two signals. If N in Equation (1-4) is not zero, the phase meter cannot know the actual phase ⁇ , which is To avoid this ambiguous phenomenon, the measurement distance must be limited to the length of the measuring ruler. If you want to measure a longer distance, you need to increase the length of the measuring ruler, that is, increase the modulation wavelength ⁇ AM.
  • the resolution is determined by two factors, one is the length of the measuring ruler, and the other is the degree of division of the measuring ruler (determined by the resolution of the phase meter).
  • the scale division of the measuring ruler should be fine (multiple) (high-resolution phase meter), and the length of the measuring ruler should be short, which will make the distance measurement range smaller.
  • at least two measuring rulers of different lengths must be used. The long ruler determines the range, the short ruler determines the resolution, and the phase meter determines the two.
  • the degree of division of the ruler scale is the degree of division of the ruler scale.
  • the phase meter only has a resolution of 1/1000
  • the modulation wavelength is 2m
  • the modulation frequency is 150MHz. In this way, high-frequency circuits must be processed. Therefore, the conventional phase method is used for ranging, which is difficult to make.
  • the basic block diagram of the conventional pulse distance measuring device is shown in Figure 2.
  • the system processor sends a trigger signal to the pulse generator, and then drives the laser to emit a narrow and high-peak light pulse. After it is reflected by the target to be measured, it returns To the receiving system, the light detector converts the returned light pulses into electrical pulses, and then amplifies the amplitude to a positioning stage through an amplifier. Due to the difference in reflectance between the distance of the target distance and the target The difference is that the amplitude of the returned signal changes greatly. In order to obtain the accuracy of the timing, it is not affected by the change of the signal strength. Therefore, a pulse height discriminator must be designed. It selects an appropriate threshold point in order to trigger the stop pulse.
  • the timing circuit calculates the round-trip time ⁇ of the light pulse, and finally the processor uses formula (1-7) to calculate the distance of the target object ⁇
  • Ng is the refractive index of air.
  • the accuracy of distance measurement will be determined by the measurement accuracy of time T. Therefore, to obtain high-precision distance measurement, a high-precision time-distance measurement circuit is required.
  • a low-frequency clock In order to save power consumption, you can use a low-frequency clock to count and select Appropriate time interpolation technology uses time interpolation to subdivide the part that is less than one clock (timing clock).
  • FIG. 3 is a timing diagram of time-to-digital conversion based on low-frequency clock counting.
  • the system uses 10MHz as the timing frequency, then the time interval range of Ta and Tb will fall between 100 ⁇ 200 ns. The following will use the time-amplitude conversion method to estimate the time interval subdivision for this range, assuming 100 ⁇ 200 ns The pulse has been converted into voltage.
  • the resolution is about 0.1ns (100ns / 1024), which is equivalent to a spatial resolution of 15mm.
  • the A / D converter must have at least 14 bits, or increase the timing clock to 100 MHz, so that the time range to be subdivided is reduced to 10ns. Therefore, the conventional pulse method is also quite complicated in circuit design, which is not practical. need.
  • An object of the present invention is to provide a pulse wave reflection oscillation device and method for ranging, which have Simple circuit design, high measurement accuracy, low cost and easy implementation.
  • the principle of the present invention is to achieve the above-mentioned object by a pulse wave reflection oscillation method. It determines the round-trip propagation time between the reference point and the measured point by measuring the oscillation period of the dead-cycle of the reflected wave. With the use of a frequency counter to measure the oscillation period, it can be known under extremely high precision. Distance value.
  • FIG. 1 is a basic block diagram of a conventional phase method ranging device
  • FIG. 2 is a basic block diagram of a conventional pulse method ranging device
  • FIG. 3 is a time-to-digital conversion timing diagram of low-frequency clock counting in the conventional pulse method ranging;
  • FIG. 4 is a schematic diagram of the ranging method of the pulse wave reflection oscillation method of the present invention.
  • Figure 5 is a basic block diagram of the laser ranging of the pulse reflection oscillation method of the present invention.
  • FIG. 6 is a block diagram of a fiber propagation delay measurement system designed by the pulse wave reflection oscillation method of the present invention
  • FIG. 7 is a pulse wave reflection oscillator with a cable as a delay line
  • Figure 8 is a schematic diagram of a cable breakpoint measurement system.
  • Fig. 9 is a circuit diagram of a reflected pulse wave passing. detailed description
  • FIG. 4 is a schematic diagram of the distance measurement by the pulse wave reflection oscillation method of the present invention.
  • the transmitter sends the first pulse of Pla, and after reflection by the mirror M1, the receiver will receive The optical signal is converted into an electrical signal, and then the first pulse of Plb is generated, and the second pulse of Pla is re-triggered to form a periodic pulse train.
  • the transmitter sends the first pulse of P2a
  • the receiver converts the received optical signal into an electric signal, and then generates a first pulse of P2b, triggers a second pulse of P2a again, and forms a periodic pulse train.
  • the distance R between the mirror M1 and the mirror M2 is Cx (T2-Tl) / 2
  • the accuracy of measuring the distance R can be determined by T2-T1 Decision, so if you can accurately measure the period T1 and T2, you can get high-precision distance measurement, and T1 or T2 usually Can be accurately measured by the frequency counter.
  • the required round trip time is about 1000 ns, and the oscillation frequency is about 1 MHz. If the frequency counting time is 1 In one second, a counting error is generated. The relative error of the round-trip time measurement is one millionth, and the distance measurement error is 0.15 mm (150 m / l 000000). Since the pulse wave reflection oscillation method uses a frequency counter to measure the oscillation frequency, as long as the frequency counting time is long, the measurement of the pulse wave round-trip time is very accurate. Therefore, when designing the ranging system, the focus is not on timing ( The design of the frequency counter is quite simple), while in the transmitter circuit and the receiver circuit.
  • FIG. 5 is a basic block diagram of laser ranging based on pulse reflection oscillation method.
  • the laser is used as the light source.
  • the beam splitter allows the laser to pass, while the reflected light is deflected toward the light detector (PIN).
  • the electrical signal converted by the detector is amplified to an appropriate level, and the pulse generating circuit 2 generates a trigger pulse (Plb, P2b). Its pulse width is wide. On the one hand, it sends a signal to the frequency counter, and on the other hand, the trigger pulse is generated.
  • Circuit 1 generates a narrow pulse (Pla, P2a), and then drives the laser to emit light, starting with START to activate the pulse signal.
  • the aforementioned mirror M1 and mirror M2 of FIG. 4 may be replaced by the movable mirror (Mirror) of FIG. 5.
  • the pulse wave reflection oscillation ranging method the working principle is the same. Therefore, the pulse wave reflection oscillation ranging method proposed by the present invention It can also be used in optical fiber propagation delay measurement system and cable breakpoint measurement system, which are briefly described below.
  • the micro-switch PB is manually pressed to trigger the pulse generator (Trigl) to generate a pulse width of 10 ns.
  • the transmitter is an electric / optical conversion module consisting of a laser and a current drive circuit, which converts the electric pulse into a light pulse with a wavelength of 1310 nm; a multimode coupler 50:50 ratio) on the one hand couples the light pulse from the transmitter to the fiber under test, on the other hand couples Fresnd reflected light from the end face of the fiber to the receiver; the receiver is an optical / electrical conversion module, which consists of light
  • the detector PIN, transimpedance amplifier, and postamp combine to convert the input optical signal into an electrical signal and amplify it to the ECL level.
  • an end-choice circuit is designed, which allows the reflection pulse rl (from the end face of the coupler), or the reflection pulse r2 (from the fiber end face ), One of them passes, and widens its pulse width to 20ns (for use by lower frequency counters).
  • the reflected pulse passed on the one hand triggers the pulse generator (Trig2) to form a closed-loop oscillation, and on the other hand passes the ECL / TTL conversion circuit for counting by the counter; the computer reads the counter through the I / O interface Take the data, and then calculate the oscillation period T, which is a combination of the system propagation delay T sys and the fiber propagation delay T fib .
  • T sys system propagation delay, representing the sum of the propagation delays of the components that make up the system, including electronic components, optocouplers, lasers, PIN ...
  • T fib propagation delay for fiber
  • L is the length of the fiber
  • N flb is the refractive index of the fiber
  • the cable breakpoint measurement system designed and applied by the pulse wave reflection oscillation method please refer to FIG. 7.
  • Loop2 is the oscillation circuit
  • the breakpoint The position can be determined by the measurement of the oscillation period. See Figure 8 again for the cable breakpoint Schematic diagram of the position measurement system.
  • the pulse generator When the START pulse is triggered, the pulse generator generates a narrow pulse of 10ns, and the transmitter (made by MC10116) sends it to the reference cable; the transmission signal (T) and the breakpoint reflection signal ( R) —From the receiver (also composed of MC10116), the receiver is a two-stage amplifier, which amplifies the reflected signal to the ECL level; the reflected pulse wave passes through the circuit, and it only allows the reflected pulse wave to pass, and generates R of 20ns -Pass pulse signal in order to trigger the pulse generator again.
  • the ECL / TTL conversion circuit converts the ECL level signal into a TTL level signal so that the frequency counter can count; the computer reads the data from the frequency counter through the I / O interface, and then performs calculations to estimate the location of the breakpoint.
  • Figure 9 is a circuit diagram of the reflected pulse wave passing, which is a combination of a two-bit shift register (made by a D-type flip-flop MC10131) and a 20 ns delay circuit. It blocks the T pulse and allows the R pulse to pass. The 20 ns delay circuit widens the pulse width of the R pulse to 20 ns.
  • the measurement medium may be at least air, water, optical fiber, and cable, but it is not limited thereto.

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • General Physics & Mathematics (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Optical Radar Systems And Details Thereof (AREA)

Abstract

La présente invention concerne un dispositif d'oscillation à réflexion d'ondes pulsées servant à la mesure de distance ainsi que son procédé permettant de mesurer des distances. Le procédé d'oscillation à réflexion d'ondes pulsées consiste à déterminer le temps de transmission aller-retour entre le point de référence et le point mesuré au moyen de la mesure de la période d'oscillation d'une boucle fermée d'une onde de réflexion, à mesurer la période d'oscillation à l'aide d'un compteur de fréquence, puis à obtenir la valeur de distance avec une très haute précision. Dans cette invention en particulier, l'impulsion de réflexion reçue est utilisée comme élément déclenchant l'impulsion d'émission suivante, la conception du circuit et sa fabrication sont relativement simples et une très haute précision peut être atteinte.
PCT/CN2004/001045 2003-09-18 2004-09-14 Dispositif d'oscillation a reflexion d'ondes pulsees servant a la mesure de distance et procede associe WO2005031258A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN03157357.6 2003-09-18
CN03157357.6A CN1598616A (zh) 2003-09-18 2003-09-18 用于测距之脉波反射振荡装置及其方法

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CN103427900B (zh) * 2012-05-18 2015-11-25 中国移动通信集团公司 一种光纤非对称性补偿方法、设备及系统
CN107356937A (zh) * 2017-08-25 2017-11-17 长春德信光电技术有限公司 一种基于激光探测技术的行走机器人碰撞预警装置
CN108398695B (zh) * 2018-01-15 2020-10-02 北京航空航天大学 一种基于接收端光纤色散的高光谱激光雷达系统
EP3521856B1 (fr) * 2018-01-31 2023-09-13 ams AG Agencement de temps de vol et procédé de mesure de temps de vol

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1508625A (en) * 1974-09-11 1978-04-26 Simrad As Methods of and apparatus for drawing sonar echo signals on display screens
JPS5995404A (ja) * 1982-11-24 1984-06-01 Nippon Seiko Kk 測距装置
JPH07280932A (ja) * 1994-04-12 1995-10-27 Matsushita Electric Ind Co Ltd 超音波距離測定装置
US5511041A (en) * 1992-01-02 1996-04-23 Endress + Hauser Gmbh + Co. Process for setting the transmission frequency of a distance measuring instrument operating according to the echo-sounding principle
JPH09229622A (ja) * 1996-02-21 1997-09-05 Mitsubishi Heavy Ind Ltd 水中用レーザ測距装置
CN1357746A (zh) * 2000-12-12 2002-07-10 哈尔滨工业大学 回波触发近距离激光测距方法

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1508625A (en) * 1974-09-11 1978-04-26 Simrad As Methods of and apparatus for drawing sonar echo signals on display screens
JPS5995404A (ja) * 1982-11-24 1984-06-01 Nippon Seiko Kk 測距装置
US5511041A (en) * 1992-01-02 1996-04-23 Endress + Hauser Gmbh + Co. Process for setting the transmission frequency of a distance measuring instrument operating according to the echo-sounding principle
JPH07280932A (ja) * 1994-04-12 1995-10-27 Matsushita Electric Ind Co Ltd 超音波距離測定装置
JPH09229622A (ja) * 1996-02-21 1997-09-05 Mitsubishi Heavy Ind Ltd 水中用レーザ測距装置
CN1357746A (zh) * 2000-12-12 2002-07-10 哈尔滨工业大学 回波触发近距离激光测距方法

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