CN114740488A - Laser ranging method and device - Google Patents
Laser ranging method and device Download PDFInfo
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- CN114740488A CN114740488A CN202210360367.9A CN202210360367A CN114740488A CN 114740488 A CN114740488 A CN 114740488A CN 202210360367 A CN202210360367 A CN 202210360367A CN 114740488 A CN114740488 A CN 114740488A
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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
- 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
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- G01S17/08—Systems determining position data of a target for measuring distance only
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Abstract
The invention discloses a laser ranging method and a device, wherein the method comprises the following steps: respectively generating a group of signals at each measuring point, wherein the group of signals comprise a first laser signal, a local oscillator signal and a reference signal, and the first laser signal comprises a plurality of measuring tape signals with different frequencies; respectively transmitting corresponding first laser signals to a measured object at each measuring point position; receiving a second laser signal corresponding to the first laser signal returned by the measured object, and mixing the second laser signal with a corresponding local oscillator signal to obtain multiple difference frequency signals; respectively calculating the phase difference between each group of multiple difference frequency signals and the corresponding reference signals; calculating the distance of the measured object according to all the phase differences; the problem of single laser rangefinder measurement leak survey appears easily is solved, uses a plurality of measuring point positions and the measuring tape signal of different frequencies when measuring the testee, and measuring result is more accurate.
Description
Technical Field
The invention relates to the technical field of laser ranging, in particular to a laser ranging method and device.
Background
The laser ranging method is characterized in that a laser emitter emits a laser beam to a measured object by utilizing the characteristics of good monochromaticity and coherence, strong directivity and the like of laser, the distance value between laser ranging equipment and the measured object can be calculated by calculating the time difference between the emission and the reception of the laser beam, and the laser ranging method is widely applied to the fields of buildings, industrial automation and the like.
In practical application, because the field angle of a single laser ranging device is small, missing measurement is easy to occur in the measurement process of a measured object, and a measurement result obtained by a single laser measuring ruler may have a large error, so that measurement deviation exists.
Disclosure of Invention
The present invention is directed to at least solving the problems of the prior art. Therefore, the invention provides a laser ranging method and device, which can solve the problem of missing measurement in the measurement process, and the provided ranging method is more accurate in ranging and smaller in measurement deviation.
In a first aspect of the present invention, a laser ranging method and apparatus are provided, which includes the following steps:
generating a group of signals on each measuring point respectively, wherein the group of signals comprise a first laser signal, a local oscillator signal and a reference signal, and the first laser signal comprises a plurality of measuring rule signals with different frequencies;
transmitting the corresponding first laser signals to a measured object at each measuring point position respectively;
receiving a second laser signal corresponding to the first laser signal returned by the measured object, and mixing the second laser signal with the corresponding local oscillator signal to obtain various difference frequency signals;
respectively calculating the phase difference between each group of the multiple difference frequency signals and the corresponding reference signal;
and calculating the distance of the measured object according to all the phase differences.
According to the embodiment of the invention, at least the following technical effects are achieved:
the method carries out laser measurement on a measured object through a plurality of measurement point positions together, firstly, each measurement point position can generate measurement scale signals with different frequencies, the measurement scale signals with different frequencies ensure the accuracy of distance measurement, secondly, laser signals are sent to the measured object from each measurement point position, the problem of missing measurement possibly occurring in single laser ranging is solved, then, a difference frequency signal obtained by mixing the laser signals and local oscillator signals and a reference signal are utilized to calculate the phase difference, the signals have robustness and are not easy to distort, the obtained phase difference is more accurate, finally, the distance of the measured object is calculated by utilizing all the phase differences, all the phase differences comprise the measurement scale signals with different frequencies and the laser measurement is carried out on each measurement point position, and the accuracy of the measured value of the measured object is greatly improved.
According to some embodiments of the invention, calculating the phase difference between the plurality of difference frequency signals and the reference signal comprises:
respectively generating a group of signals at each measuring point, wherein the group of signals comprise a first laser signal, a local oscillator signal and a reference signal, and the first laser signal comprises a plurality of measuring tape signals with different frequencies;
extracting a plurality of second sampling points with stable waveforms from any one of the plurality of difference frequency signals, filtering the plurality of second sampling points and performing multiple times of interpolation to obtain a second sampling point set;
extracting a plurality of peak count values from the first sampling point set and averaging to obtain a first average value, and extracting a plurality of peak count values from the second sampling point set and averaging to obtain a second average value;
and calculating a difference value according to the first average value and the second average value, and calculating a phase difference according to the difference value.
According to some embodiments of the invention, before the calculating the distance of the measured object according to all the phase differences, the method further comprises the steps of:
and carrying out error compensation on the phase difference, wherein the error compensation comprises temperature error compensation and calibrated error compensation.
According to some embodiments of the invention, temperature error compensation of the phase difference comprises the steps of:
selecting a corresponding preset phase drift value according to the temperature;
and compensating the phase difference according to the phase drift value.
According to some embodiments of the invention, the error compensation of the calibration of the phase difference comprises the steps of:
selecting a preset phase error value according to the frequency of the measuring scale signal;
and compensating the phase difference according to the phase error value.
In a second aspect of the present invention, there is provided a laser ranging apparatus comprising:
the laser ranging units are arranged at different measuring points and are aligned to a measured object, each laser ranging unit comprises a control unit, a phase-locked loop unit, a frequency mixing unit, a laser emitting unit and a laser receiving unit, the control unit, the phase-locked loop unit and the frequency mixing unit are electrically connected with each other, the laser emitting unit is electrically connected with the phase-locked loop unit, and the laser receiving unit is electrically connected with the frequency mixing unit; the phase-locked loop unit is used for generating a reference signal, a local oscillator signal and a first laser signal, wherein the first laser signal comprises a plurality of measuring scale signals with different frequencies; the laser emission unit is used for emitting the first laser signal; the laser receiving unit is used for receiving a second laser signal reflected by the measured object according to the first laser signal; the frequency mixing unit is used for performing frequency mixing filtering on the second laser signal and the local oscillator signal to obtain various difference frequency signals; the control unit is used for calculating the phase difference between the various difference frequency signals and the reference signal;
and the processor is connected with the laser ranging units through a bus and used for calculating the distance of the measured object according to all the phase differences.
According to the embodiment of the invention, at least the following technical effects are achieved:
the laser distance measuring units acquire measuring data, the field angle of laser measurement is increased, the problem of missing measurement of a single laser in the measuring process is reduced, the phase-locked loop unit can transmit measuring tape signals with various different frequencies, the frequency mixing unit mixes the second laser signal with the local oscillator signal to obtain a difference frequency signal, the phase difference is calculated through the difference frequency signal and a reference signal, the error of equipment in the measuring process can be effectively reduced, the measuring accuracy is improved, the processor is connected with the laser distance measuring units through a bus, and the circuit design complexity of the system is simplified.
According to some embodiments of the present invention, the laser ranging unit further comprises an automatic gain unit, the automatic gain unit is electrically connected to the frequency mixing unit, and the automatic gain unit is configured to amplify and gain the second laser signal.
According to some embodiments of the present invention, the laser ranging unit further includes a first AD conversion unit and a second AD conversion unit, the first AD conversion unit is electrically connected to the phase-locked loop unit and the control unit, and is configured to perform analog-to-digital conversion on the reference signal and input the converted reference signal to the control unit; the second AD conversion unit is electrically connected with the frequency mixing unit and the control unit and is used for performing analog-to-digital conversion on the difference frequency signal and inputting the converted difference frequency signal to the control unit.
According to some embodiments of the present invention, the laser ranging unit further includes a temperature compensation unit, the temperature compensation unit is electrically connected to the control unit, and the temperature compensation unit is configured to select a corresponding preset phase drift value according to the current environment temperature of the measurement point location, and compensate the phase difference according to the phase drift value.
According to some embodiments of the invention, the laser ranging apparatus further comprises a communication unit electrically connected with the processor, the communication unit being configured to bi-directionally communicate with the processor and save a calculation result of the processor.
Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
Drawings
The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:
FIG. 1 is a flow chart of a laser ranging method according to an embodiment of the present invention;
FIG. 2 is a flow chart of phase difference calculation provided by one embodiment of the present invention;
FIG. 3 is a block diagram of a laser ranging apparatus according to an embodiment of the present invention;
FIG. 4 is a block diagram of a laser ranging unit according to an embodiment of the present invention;
FIG. 5 is a waveform diagram of a reference signal provided by one embodiment of the present invention;
fig. 6 is a waveform diagram of a difference frequency signal according to an embodiment of the present invention.
Reference numerals: 100. a laser ranging unit; 200. a processor; 300. a communication unit; 400. a display unit; 101. a control unit; 102. a phase-locked loop unit; 103. a mixing unit; 104. a first AD conversion unit; 105. a second AD conversion unit; 106. an automatic gain unit; 107. a photocurrent amplifying unit; 108. a laser emitting unit; 109. a laser receiving unit; 110. an optical lens; 111. and a temperature compensation unit.
Detailed Description
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention, and are not to be construed as limiting the present invention.
In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "axial", "radial", "circumferential", and the like, indicate orientations and positional relationships based on the orientations and positional relationships shown in the drawings, and are used merely for convenience in describing the present invention and for simplicity in description, and do not indicate or imply that the device or element so referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore, should not be construed as limiting the present invention. Furthermore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless otherwise specified.
In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.
Referring to fig. 1, an embodiment of the present invention provides a laser ranging method, including the following steps:
step S101, a group of signals are respectively generated at each measuring point position, the group of signals comprise a first laser signal, a local oscillator signal and a reference signal, and the first laser signal comprises a plurality of measuring rule signals with different frequencies.
And S102, respectively emitting corresponding first laser signals to the measured object at each measuring point position.
And S103, receiving a second laser signal corresponding to the first laser signal returned by the measured object, and mixing the second laser signal with a corresponding local oscillator signal to obtain various difference frequency signals.
And step S104, calculating the phase difference between each group of various difference frequency signals and the corresponding reference signals.
And step S105, calculating the distance of the measured object according to all the phase differences.
According to the embodiment of the invention, at least the following technical effects are achieved:
the method carries out laser measurement on a measured object through a plurality of measurement point positions together, firstly, each measurement point position can generate measurement scale signals with different frequencies, the measurement scale signals with different frequencies ensure the accuracy of distance measurement, secondly, laser signals are sent to the measured object from each measurement point position, the problem of missing measurement possibly occurring in single laser ranging is solved, then, a difference frequency signal obtained by mixing the laser signals and local oscillator signals and a reference signal are utilized to calculate the phase difference, the signals have robustness and are not easy to distort, the obtained phase difference is more accurate, finally, the distance of the measured object is calculated by utilizing all the phase differences, all the phase differences comprise the measurement scale signals with different frequencies and the laser measurement is carried out on each measurement point position, and the accuracy of the measured value of the measured object is greatly improved.
Referring to fig. 2, 5 and 6, in some embodiments of the present invention, the step 104 of calculating the phase difference between each set of the plurality of difference frequency signals and the corresponding reference signal comprises the steps of:
step 1041, extracting a plurality of first sampling points with stable waveforms from the reference signal, filtering the plurality of first sampling points, and performing multiple times of interpolation to obtain a first sampling point set.
Step 1042, extracting a plurality of second sampling points with stable waveforms from any one of the plurality of differential signals, filtering the plurality of second sampling points and performing multiple interpolation to obtain a second sampling point set.
Step 1043, extracting a plurality of peak count values from the first set of sampling points and averaging to obtain a first average value, and extracting a plurality of peak count values from the second set of sampling points and averaging to obtain a second average value.
And step 1044, calculating a difference value according to the first average value and the second average value, and calculating a phase difference according to the difference value.
By extracting sampling points with stable waveforms in the reference signal and the difference frequency signal, then extracting a plurality of peak count values from the sampling point set and averaging, and calculating the phase difference through the average value, the accuracy of the adopted sample in the phase difference calculation is ensured, and the measurement precision is higher.
In some embodiments of the present invention, before calculating the distance of the measured object according to all the phase differences, the method further includes the steps of:
and carrying out error compensation on the phase difference, wherein the error compensation comprises temperature error compensation and calibrated error compensation.
By carrying out error compensation on the phase difference, the error caused by the interference of external factors such as the transmission process or the temperature of the laser signal is compensated, so that the measurement result is more accurate.
In some embodiments of the present invention, the error compensation is performed on the phase difference, wherein performing the temperature error compensation comprises the steps of:
and S2001, selecting a corresponding preset phase drift value according to the current environment temperature of the measurement point.
And step S2002, compensating the phase difference according to the phase drift value.
The preset phase drift value keeps the unique variable temperature by fixing other conditions to obtain a measurement error value at each temperature, and in the laser ranging process, the corresponding error value is selected according to the current environment temperature of the measurement point to compensate the ranging value, so that the temperature error compensation is accurately carried out, and the measurement result is more accurate.
In some embodiments of the present invention, the error compensation is performed on the phase difference, wherein the error compensation for calibration comprises the steps of:
step S3001, selecting a preset phase error value according to a frequency of the measurement signal.
And step S3002, compensating the phase difference according to the phase error value.
The preset phase error value is obtained by fixing the actual distance between the measured object and the laser ranging unit through the measuring range of the measuring scale and the difference value between the actual distance and the measuring distance of the laser ranging unit, and the calibrated error compensation is carried out through the frequency of the currently used measuring scale signal during laser ranging, so that the measuring result is more accurate.
To facilitate understanding by those skilled in the art, an embodiment of the present invention provides a data processing procedure of a laser ranging method, including:
firstly, a processor of the laser ranging unit generates a first group of measuring signals by controlling a phase-locked loop, wherein the measuring signals comprise a reference signal, a local oscillator signal and a measuring tape signal, and the three signals are transmitted at the same time.
Secondly, the processor starts the AD conversion unit to collect N sampling points [ x ] of the reference signal0,x1,......xn]Simultaneously collecting N sampling points [ y ] of the difference frequency signal after frequency mixing0,y1,......yn]Extracting stable waveform from reference signal sampling point, and then extracting K sampling points X ═ X0,x1,......xk]Filtering, and performing z-multiple interpolation to obtain final sampling point data [ x ]0,x1,......x(k*z)]And extracting a plurality of peak count values and averaging to obtain the SIX.
In the same way, when the laser distance measuring unit receives the returned measuring tape signal, the local oscillator signal and the returned measuring tape signal are subjected to frequency mixing through the frequency mixing unit to obtain a difference frequency signal, and K sampling points Y ═ Y [ Y ] after stable waveforms are extracted from the sampling points of the difference frequency signal0,y,......yk]Filtering, and performing z multiple interpolation to obtain final sampling point data [ y ]0,y1,......y(k*z)]And extracting a plurality of peak count values and averaging to obtain SIY.
Thirdly, if the sampling frequency of the AD conversion unit is F, the sampling point count of the reference signal and the difference frequency signal in one period is M ═ F/F0＝F/f′1Wherein f is0Representing the frequency, f 'of the reference signal'1Representing the frequency of the difference signal. Therefore, the calculation formula of the count value difference SI between the reference signal and the difference frequency signal is as follows:
where M represents the sample point count within the period and z represents the interpolation multiple.
The sampling count in a single period is M, the number of sampling points after interpolation is N-M x z, the phase of the count value of each sampling point is N/360, and the phase difference is theta1SI (N/360) + errorAnd compensating, wherein the error compensation comprises calibrated error compensation and temperature compensation error compensation.
Fourthly, according to the phase difference, the distance measurement value M1 under the frequency of the first measuring scale can be calculated, and the distance measurement values of other measuring scales such as M2, M3 and the like can be calculated by analogy, and the final distance measurement value is calculated by a comparison method or a centering method. In the field, the measurement using the measuring rule with longer wavelength is called rough measurement, the measurement using the measuring rule with shorter wavelength is called fine measurement, the comparison method is that firstly, 5 is added or subtracted on the rough measurement parity value corresponding to the highest position (such as meter position) of the fine measurement to form a distance value with unidirectional error, then the distance value is gradually decreased or added by a certain number, and the distance value is gradually compared with the highest position value of the fine measurement until the highest position of the fine measurement is equal to the rough measurement parity. At this time, the value of the rough measurement higher than the most accurate measurement is combined with the accurate measurement value to obtain the correct distance value. Although the comparison process requires a plurality of subtraction and comparison operations, these operations are performed automatically by the microprocessor of the range finder, so the operations are fast and error-free. The essence of the centering method is that the rough measurement value is added and subtracted with corresponding integer numbers based on the fine measurement meter position without error, and the meter position corresponding to the rough measurement value is adjusted to be 5, and at the moment, even if the rough measurement has an error of 4m, the rough distance difference can not be generated. For example, if the rough measurement value is 269.9m, if there is an error of 0.1m without centering, the rough measurement value will be poor, if centering is performed, that is, 269.9-4 equals 265.9m, and if there is an error of +4m (265.9+4 equals 269.9m), the rough measurement tolerance will not be poor, which means that the rough measurement tolerance can reach 4m after centering.
According to the embodiment of the invention, at least the following technical effects are achieved:
the error rate of a sampling point set is reduced by selecting a stable waveform and a multiple difference value to calculate the phase difference, the error of different measuring rulers is calibrated, and the error compensation of temperature compensation and calibration is combined, so that the distance measurement error is effectively reduced, and the measuring ruler signals of multiple frequencies are combined for measurement, so that the measurement distance can be increased, and the measurement precision can also be improved.
The final measurement result is calculated by the distance measurement values calculated by the frequencies of the measuring rulers.
Referring to fig. 3 and 4, an embodiment of the present invention provides a laser ranging apparatus including:
the laser ranging units 100 are arranged at different measuring points and are aligned to a measured object, each laser ranging unit 100 comprises a control unit 101, a phase-locked loop unit 102, a frequency mixing unit 103, a laser emitting unit 108 and a laser receiving unit 109, the control unit 101, the phase-locked loop unit 102 and the frequency mixing unit 103 are electrically connected with each other, the laser emitting unit 108 is electrically connected with the phase-locked loop unit 102, and the laser receiving unit 109 is electrically connected with the frequency mixing unit 103; the phase-locked loop unit 102 is configured to generate a reference signal, a local oscillator signal, and a first laser signal, where the first laser signal includes multiple measurement ruler signals with different frequencies; the laser emitting unit 108 is used for emitting a first laser signal; the laser receiving unit 109 is configured to receive a second laser signal reflected by the object to be measured according to the first laser signal; the frequency mixing unit 103 is configured to perform frequency mixing filtering on the second laser signal and the local oscillator signal to obtain multiple difference frequency signals; the control unit 101 is used to calculate the phase difference between the various difference frequency signals and the reference signal.
And the processor 200 is connected with the plurality of laser ranging units 100 through a bus and used for calculating the distance of the measured object according to all the phase differences.
According to the embodiment of the invention, at least the following technical effects are achieved:
the laser ranging units 100 acquire measurement data, the field angle of laser measurement is increased, the problem of missing measurement of a single laser in the measurement process is reduced, the phase-locked loop unit 102 can transmit measurement ruler signals with various different frequencies, the frequency mixing unit 103 mixes a second laser signal with a local oscillator signal to obtain a difference frequency signal, and then calculates a phase difference through the difference frequency signal and a reference signal, so that errors of equipment in the measurement process can be effectively reduced, the measurement accuracy is improved, the processor 200 is connected with the laser ranging units 100 through a bus, and the circuit design complexity of the system is simplified.
In some embodiments of the present invention, the laser ranging unit 100 further includes an automatic gain unit 106, the automatic gain unit 106 is electrically connected to the frequency mixing unit 103, the automatic gain unit 106 is configured to amplify the second laser signal for gain, the laser receiving unit 109 converts the second laser signal from an optical signal form into an electrical signal form, the automatic gain unit 106 amplifies the second laser signal in the electrical signal form for gain, and automatically controls and adjusts an amplification factor of the electrical signal, so that the electrical signal meets an input requirement of the frequency mixing unit 103, and a situation that the measurement scale signal cannot be obtained by the frequency mixing unit 103 is prevented.
In some embodiments of the present invention, the laser ranging unit 100 further includes a first AD conversion unit 104 and a second AD conversion unit 105, where the first AD conversion unit 104 is electrically connected to the phase-locked loop unit 102 and the control unit 101, and is configured to perform analog-to-digital conversion on the reference signal and input the reference signal to the control unit 101; the second AD conversion unit 105 is electrically connected to the mixing unit 103 and the control unit 101, and is configured to perform analog-to-digital conversion on the difference frequency signal and then input the difference frequency signal to the control unit 101, where the AD conversion unit converts the analog signal into a digital signal, meets the input condition of the control unit 101, and directly inputs data to the control unit 101 for subsequent calculation.
In some embodiments of the present invention, the laser ranging unit 100 further includes a temperature compensation unit 111, the temperature compensation unit 111 is electrically connected to the control unit 101, the temperature compensation unit 111 is configured to select a corresponding preset phase drift value according to a current environment temperature of the measurement point, compensate the phase difference according to the phase drift value, the temperature compensation unit 111 stores an error value at each temperature, and automatically perform error compensation according to a temperature at which the laser ranging unit 100 is located, so that a measurement result of the laser ranging unit 100 is more accurate.
In some embodiments of the present invention, the laser ranging apparatus further includes a communication unit 300, the communication unit 300 is electrically connected to the processor 200, the communication unit 300 is configured to bidirectionally communicate with the processor 200 and store the calculation result of the processor 200, and the server receives and stores the laser ranging data sent by the processor 200, so as to prevent the laser ranging data from being lost due to the failure of the laser ranging apparatus.
Referring to fig. 3 and 4, in order to facilitate understanding by those skilled in the art, according to an embodiment of the present invention, there is provided a laser ranging apparatus including a processor 200, a display unit 400, a communication unit 300, and a plurality of laser ranging units 100.
The processor 200 is connected with the display unit 400, the communication unit 300 and the plurality of laser ranging units 100, and the processor 200 independently controls the relevant operation of each laser ranging unit 100, obtains the measurement data of the laser ranging units 100, displays the measurement data in real time through the display unit 400, and transmits the measurement data to the server through the communication unit 300.
And a communication unit 300 connected to the processor 200 for bi-directional communication between the processor 200 and a server, wherein the server can issue control commands through the communication unit 300, and the communication unit 300 can transmit measurement data of the processor 200, and the communication unit 300 includes at least one of 4G, NB, LORA, and serial ports.
And the display unit 400 is connected with the processor 200, displays the measurement data of the laser ranging device and the operation state parameters of the system in real time according to the control of the processor 200, and visually displays the information.
The laser ranging units 100 are connected with the processor 200 through bus interfaces, each laser ranging unit 100 is fixedly installed according to different angles and used for executing ranging operation, the processor 200 controls parameter information and ranging work of each laser ranging unit 100 through the interfaces, the processor 200 and the laser ranging units 100 are communicated through serial ports, and the processor 200 can also control a power switch of the laser ranging units 100.
A plurality of laser ranging units 100, each laser ranging unit 100 including a control unit 101, a phase-locked loop unit 102, a photocurrent amplifying unit 107, a laser emitting unit 108, a laser receiving unit 109, an optical lens 110, an automatic gain unit 106, a mixing unit 103, a temperature compensating unit 111, a first AD converting unit 104, and a second AD converting unit 105; the control unit 101, the phase-locked loop unit 102 and the frequency mixing unit 103 are electrically connected with each other, a first AD conversion unit 104 is electrically connected between the control unit 101 and the phase-locked loop unit 102, a second AD conversion unit 105 is electrically connected between the control unit 101 and the frequency mixing unit 103, the phase-locked loop unit 102 is electrically connected with the laser emitting unit 108, one end of the photocurrent amplifying unit 107 is electrically connected with the control unit 101, the other end of the photocurrent amplifying unit is electrically connected with the laser emitting unit 108, the frequency mixing unit 103 is electrically connected with the automatic gain unit 106, one end of the laser receiving unit 109 is electrically connected with the automatic gain unit 106, the other end of the laser receiving unit is electrically connected with the optical lens 110, and the temperature compensating unit 111 is directly electrically connected with the control unit 101.
The control unit 101 is a single chip for controlling the emission of the laser signal, the reception of the optical signal, and the distance measurement calculation of the laser distance measurement unit 100, and is responsible for interacting with the control command of the processor 200.
The phase-locked loop unit 102 receives a command of the control unit 101, and is configured to generate a reference signal, a local oscillator signal, and a measurement scale signal with a different frequency, and in a process of transmitting the measurement scale signal, the control unit 101 adjusts a working current of the measurement scale signal through the laser transmitting unit 108 through the controlled photocurrent amplifying unit 107, so as to ensure stability of the laser transmitting unit 108.
The laser receiving unit 109 receives the reflected optical signal through the optical lens 110, converts the optical signal into a weak electrical signal, and then automatically controls and adjusts the amplification factor of the electrical signal through the automatic gain unit 106, so that the electrical signal meets the input requirement of the frequency mixing unit 103.
The frequency mixing unit 103 is configured to receive the signal adjusted by the automatic gain unit 106 and the local oscillator signal, perform frequency mixing filtering, and automatically output a difference frequency signal with a constant phase.
An AD conversion unit for sampling the reference signal and the difference frequency signal output by the mixing unit 103, converting the analog signal into a digital signal, and the control unit 101 calculates the phase difference of the object to be measured based on the sampled reference signal and difference frequency signal, thereby calculating the ranging value.
And the temperature compensation unit 111 is used for calculating a phase drift value generated by the temperature of the laser ranging equipment in the operation process, and performing phase difference compensation operation on the calculated temperature value according to the measured temperature parameter value, so as to further improve the measurement precision.
According to the embodiment of the invention, at least the following technical effects are achieved:
the laser ranging device integrates a plurality of laser ranging units 100, so that the field angle of laser measurement is increased, missing measurement of laser in the measurement process is reduced, and the display unit 400 of the laser ranging device can visually know the distance, the direction and the working state of a measured object. The photocurrent amplifying unit 107 and the automatic gain unit 106 of the laser ranging device can effectively control the stability of optical signals, and meanwhile, the temperature compensation unit 111 is combined, so that the circuit design complexity of a system is simplified, and errors caused in the measuring process of the device can be effectively reduced.
One of ordinary skill in the art will appreciate that all or some of the steps, systems, and methods disclosed above may be implemented as software, firmware, hardware, and suitable combinations thereof. Some or all of the physical components may be implemented as software executed by a processor, such as a central processing unit, digital signal processor, or microprocessor, or as hardware, or as an integrated circuit, such as an application specific integrated circuit. Such software may be distributed on computer readable media, which may include computer storage media (or non-transitory media) and communication media (or transitory media). The term computer storage media includes volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of data such as computer readable instructions, data structures, program modules or other data, as is well known to those of ordinary skill in the art. Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, Digital Versatile Disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to store the desired data and which can accessed by the computer. In addition, communication media typically embodies computer readable instructions, data structures, program modules or other data in a modulated data signal such as a carrier wave or other transport mechanism and includes any data delivery media as known to one of ordinary skill in the art.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an illustrative embodiment," "an example," "a specific example," or "some examples" or the like mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
While embodiments of the invention have been shown and described, it will be understood by those of ordinary skill in the art that: various changes, modifications, substitutions and alterations can be made to the embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.
Claims (10)
1. A laser ranging method is characterized by comprising the following steps:
respectively generating a group of signals at each measuring point, wherein the group of signals comprise a first laser signal, a local oscillator signal and a reference signal, and the first laser signal comprises a plurality of measuring tape signals with different frequencies;
transmitting the corresponding first laser signals to a measured object at each measuring point position respectively;
receiving a second laser signal corresponding to the first laser signal returned by the measured object, and mixing the second laser signal with the corresponding local oscillator signal to obtain various difference frequency signals;
respectively calculating the phase difference between each group of the multiple difference frequency signals and the corresponding reference signal;
and calculating the distance of the measured object according to all the phase differences.
2. The laser ranging method according to claim 1, wherein the calculating of the phase difference between the plurality of kinds of difference frequency signals and the reference signal comprises the steps of:
extracting a plurality of first sampling points with stable waveforms from the reference signal, filtering the plurality of first sampling points and performing multiple times of interpolation to obtain a first sampling point set;
extracting a plurality of second sampling points with stable waveforms from any one of the plurality of difference frequency signals, filtering the plurality of second sampling points and performing multiple times of interpolation to obtain a second sampling point set;
extracting a plurality of peak count values from the first sampling point set and averaging to obtain a first average value, and extracting a plurality of peak count values from the second sampling point set and averaging to obtain a second average value;
and calculating a difference value according to the first average value and the second average value, and calculating a phase difference according to the difference value.
3. The laser ranging method according to claim 1, further comprising, before the calculating the distance of the object to be measured from all the phase differences, the steps of:
and carrying out error compensation on the phase difference, wherein the error compensation comprises temperature error compensation and calibrated error compensation.
4. The laser ranging method according to claim 3, wherein the temperature error compensation of the phase difference comprises the steps of:
selecting a corresponding preset phase drift value according to the current environment temperature of the measuring point location;
and compensating the phase difference according to the phase drift value.
5. The laser ranging method of claim 3, wherein the calibrated error compensation of the phase difference comprises the steps of:
selecting a preset phase error value according to the frequency of the measuring scale signal;
and compensating the phase difference according to the phase error value.
6. A laser ranging apparatus, comprising:
the laser ranging units are arranged at different measuring points and are aligned to a measured object, each laser ranging unit comprises a control unit, a phase-locked loop unit, a frequency mixing unit, a laser emitting unit and a laser receiving unit, the control unit, the phase-locked loop unit and the frequency mixing unit are electrically connected with each other, the laser emitting unit is electrically connected with the phase-locked loop unit, and the laser receiving unit is electrically connected with the frequency mixing unit; the phase-locked loop unit is used for generating a reference signal, a local oscillator signal and a first laser signal, wherein the first laser signal comprises measuring tape signals with various frequencies; the laser emission unit is used for emitting the first laser signal; the laser receiving unit is used for receiving a second laser signal reflected by the measured object according to the first laser signal; the frequency mixing unit is used for performing frequency mixing filtering on the second laser signal and the local oscillator signal to obtain various difference frequency signals; the control unit is used for calculating the phase difference between the various difference frequency signals and the reference signal;
and the processor is connected with the laser ranging units through a bus and used for calculating the distance of the measured object according to all the phase differences.
7. The laser ranging apparatus of claim 6, wherein the laser ranging unit further comprises an automatic gain unit, the automatic gain unit is electrically connected to the mixing unit, and the automatic gain unit is configured to amplify and gain the second laser signal.
8. The laser ranging apparatus according to claim 6, wherein the laser ranging unit further comprises a first AD conversion unit and a second AD conversion unit, the first AD conversion unit is electrically connected to the phase-locked loop unit and the control unit, and is configured to perform analog-to-digital conversion on the reference signal and input the converted signal to the control unit; the second AD conversion unit is electrically connected with the frequency mixing unit and the control unit and is used for performing analog-to-digital conversion on the difference frequency signal and inputting the difference frequency signal to the control unit.
9. The laser ranging device as claimed in claim 6, wherein the laser ranging unit further comprises a temperature compensation unit, the temperature compensation unit is electrically connected to the control unit, and the temperature compensation unit is configured to select a corresponding preset phase drift value according to the current ambient temperature of the measurement point location, and compensate the phase difference according to the phase drift value.
10. The laser ranging apparatus of claim 6, further comprising a communication unit electrically connected to the processor, the communication unit configured to bi-directionally communicate with the processor and store the calculation results of the processor.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN115236685A (en) * | 2022-09-21 | 2022-10-25 | 成都量芯集成科技有限公司 | Phase method laser range unit |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN115236685A (en) * | 2022-09-21 | 2022-10-25 | 成都量芯集成科技有限公司 | Phase method laser range unit |
| CN115236685B (en) * | 2022-09-21 | 2022-12-23 | 成都量芯集成科技有限公司 | Phase method laser range unit |
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