Laser ranging system

Abstract

The utility model relates to a laser ranging system which comprises a master control circuit module, a laser emission circuit module, a light sampling signal processing circuit module, a high-precision timing circuit module and a detection signal processing circuit module. The main control circuit module drives the laser emission circuit module to emit laser to a measured target; the light sampling signal processing circuit module identifies and processes the first part of laser, obtains a timing door opening signal and sends the timing door opening signal to the high-precision timing circuit module; the detection signal processing circuit module identifies and processes the second part of laser, obtains a timing door closing signal and sends the timing door closing signal to the high-precision timing circuit module; the high-precision timing circuit module calculates a time difference signal of the timing door opening signal and the timing door closing signal and uploads the time difference signal to the main control circuit module; and the main control circuit module analyzes and calculates the time difference signal to obtain distance data. According to the invention, the influence of the amplitude and pulse width change of the echo signal on the precision of the measured target is solved, and the requirements of simple circuit design, small size, low cost and high precision are met.

Description

Technical Field

[0001] The utility model relates to the technical field of laser optoelectronics, and particularly relates to a laser ranging system. Background Art

[0002] In the early stage, the pulsed laser rangefinder system mainly improved the accuracy of the measured target distance value by improving the time measurement resolution. With the research and application of high-precision time measurement chips, the ranging accuracy of the pulsed laser has been greatly improved. However, in practical applications, since the amplitude and pulse width of the echo pulse signal are related to many factors such as the reflectivity of the measured target, the atmospheric transmittance, and the measurement angle, there are large measurement errors in the method of calculating the distance of the measured target only by relying on the traditional rising-edge trigger high-precision time measurement chip.

[0003] In order to solve the influence of the amplitude and pulse width of the echo signal on the measurement accuracy, the double-threshold or multi-threshold rising-edge moment discrimination method is often used to reduce the influence of the amplitude and pulse width of the echo signal on the ranging accuracy. Two or three thresholds are set to respectively shape the echo signal, generating a square wave signal with a slightly deviated rising edge, which enters the high-precision time measurement chip for distance analysis. The software uses the limit approximation algorithm to minimize the error of the measured target distance value. This method improves the ranging accuracy of the pulsed laser ranging system to a certain extent. However, this method requires designing a corresponding shaping processing circuit according to the threshold level, and the circuit design is too complex and not applicable to the micro laser ranging system. Summary of the Utility Model

[0004] In view of this, the purpose of the utility model is to provide a laser ranging system to overcome the technical problem that the change of the amplitude and pulse width of the echo signal has an adverse effect on the accuracy of the measured target in the prior art.

[0005] To achieve the above purpose, the utility model adopts the following technical scheme:

[0006] According to the first aspect of the utility model, a laser ranging system is provided, including a main control circuit module, a laser emission circuit module, an optical sampling signal processing circuit module, a high-precision timing circuit module, and a detection signal processing circuit module; the laser emission circuit module and the high-precision timing circuit module are respectively communicatively connected with the main control circuit module; the optical sampling signal processing circuit module and the detection signal processing circuit module are respectively communicatively connected with the high-precision timing circuit module;

[0007] The main control circuit module is used to drive the laser emission circuit module to emit laser towards the target to be measured after receiving the laser ranging instruction; the first part of the laser is split by a beam splitter, reflected, and then received by the optical sampling signal processing circuit module; the second part of the laser shoots towards the target to be measured, and after reflection, it is received by the detection signal processing circuit module;

[0008] The optical sampling signal processing circuit module is used to identify and process the first part of the laser, obtain a timing opening signal, and send the timing opening signal to the high-precision timing circuit module;

[0009] The detection signal processing circuit module is used to identify and process the second part of the laser, obtain a timing closing signal, and send the timing closing signal to the high-precision timing circuit module;

[0010] The high-precision timing circuit module is used to calculate the time difference signal between the timing opening signal and the timing closing signal, and upload the time difference signal to the main control circuit module;

[0011] The main control circuit module is used to analyze and calculate the time difference signal to obtain distance data.

[0012] Optionally, the detection signal processing circuit module includes a detector receiving circuit unit and a threshold comparison circuit unit; the threshold comparison circuit unit is respectively communicatively connected to the detector receiving circuit unit and the high-precision timing circuit module;

[0013] The detector receiving circuit unit is used to receive and process the second part of the laser, obtain a laser analog signal, and send the laser analog signal to the threshold comparison circuit module;

[0014] The threshold comparison circuit unit is used to perform threshold comparison on the laser analog signal to obtain a timing closing signal, and send the timing closing signal to the high-precision timing circuit module.

[0015] Optionally, the detector receiving circuit unit is further used to perform detector amplification and filtering processing on the second part of the laser to obtain the laser analog signal.

[0016] Optionally, the threshold comparison circuit unit is further used to compare the laser analog signal with a preset threshold voltage value, and shape and output a standard square wave digital signal as the timing closing signal.

[0017] Optionally, the main control circuit module powers on and initializes the configuration of the time measurement chip to trigger simultaneously at the rising edge and the falling edge.

[0018] Optionally, the main control circuit module is further configured to calculate distance data by using the following formula:

[0019]

[0020] Δd‘ = D1 - D2 = 0

[0021] where c is the propagation speed of light in the atmosphere; t 1u and t 2u are respectively the triggering moments of the rising edges of the shaped square-wave signals of different measured targets at the same measured distance; t 1d and t 2d are respectively the triggering moments of the falling edges of the shaped square-wave signals of different measured targets at the same measured distance; t av is the median moment of the square-wave signal output by the measured target through the threshold control and comparison circuit module; D1 and D2 are respectively the distance data of the measured target in two measurements, and Δd' is the error value of the two measurement results.

[0022] Optionally, the main control circuit module uses an STM32 single-chip microcomputer.

[0023] Optionally, the high-precision timing circuit module uses a TDC-GP2 time measurement chip, and a 16 MHz high-frequency crystal oscillator is used as the clock source peripherally.

[0024] Optionally, the main control circuit module is further configured to perform register configuration on the TDC-GP2 time measurement chip in the high-precision timing circuit module.

[0025] Optionally, the high-precision timing circuit module is further configured to upload the time difference signal to the main control circuit module through the SPI communication protocol.

[0026] One or more of the above technical solutions provided by the present utility model may have the following advantages or at least achieve the following technical effects: A laser ranging system proposed by the present utility model includes a main control circuit module, a laser emission circuit module, an optical sampling signal processing circuit module, a high-precision timing circuit module, and a detection signal processing circuit module; the main control circuit module is used to drive the laser emission circuit module to emit laser towards the target to be measured after receiving a laser ranging instruction; the first part of the laser is received by the optical sampling signal processing circuit module after being split and reflected by a beam splitter; the second part of the laser shoots towards the target to be measured and is received by the detection signal processing circuit module after being reflected; the optical sampling signal processing circuit module is used to identify and process the first part of the laser to obtain a timing opening signal and send the timing opening signal to the high-precision timing circuit module; the detection signal processing circuit module is used to identify and process the second part of the laser to obtain a timing closing signal and send the timing closing signal to the high-precision timing circuit module; the high-precision timing circuit module is used to calculate the time difference signal between the timing opening signal and the timing closing signal and upload the time difference signal to the main control circuit module; the main control circuit module is used to analyze and calculate the time difference signal to obtain distance data. The technical solution of the present application overcomes the technical problems existing in the traditional technology, solves the influence of the amplitude and pulse width changes of the echo signal on the accuracy of the target to be measured, and has a simple circuit design, which can meet the requirements of small volume, low cost, and high precision of the current laser ranging system. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present utility model. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0028] Figure 1 FIG. is a schematic structural diagram of a laser ranging system provided by an embodiment of the present utility model;

[0029] Figure 2 FIG. is a circuit schematic diagram of a laser ranging system provided by another embodiment of the present utility model;

[0030] Figure 3 FIG. is a waveform diagram of the target echo of reflectivity provided by an embodiment of the present utility model;

[0031] Figure 4 FIG. is a schematic flow diagram of register configuration provided by an embodiment of the present utility model.

[0032] The realization, functional features, and advantages of the present utility model will be further described in conjunction with embodiments with reference to the accompanying drawings. Detailed implementation manners

[0033] To make the objectives, technical solutions, and advantages of the present utility model clearer, the technical solutions of the present utility model will be described in detail below. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all of the embodiments. All other implementation manners obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts fall within the scope protected by the present utility model.

[0034] To improve the ranging accuracy of the pulsed laser ranging system and reduce the influence of the amplitude and pulse width changes of the echo signal on the ranging accuracy, the present utility model provides a convenient, small-sized, and low-cost laser ranging system. The specific embodiments and implementation manners are as follows:

[0035] Refer to Figure 1 , Figure 1 is a schematic structural diagram of a laser ranging system provided by an embodiment of the present utility model. An embodiment of the present utility model provides a laser ranging system, which may include a main control circuit module, a laser emission circuit module, an optical sampling signal processing circuit module, a high-precision timing circuit module, and a detection signal processing circuit module. Among them, the laser emission circuit module and the high-precision timing circuit module are respectively communicatively connected to the main control circuit module; the optical sampling signal processing circuit module and the detection signal processing circuit module are respectively communicatively connected to the high-precision timing circuit module.

[0036] The main control circuit module is configured to drive the laser emission circuit module to emit laser towards the target to be measured after receiving the laser ranging instruction. Figure 1 As can be seen from, the first part of the laser is received by the optical sampling signal processing circuit module after being split and reflected by the beam splitter; the second part of the laser is emitted towards the target to be measured and is received by the detection signal processing circuit module after reflection. The optical sampling signal processing circuit module is configured to identify and process the first part of the laser to obtain a timing start signal and send the timing start signal to the high-precision timing circuit module. The detection signal processing circuit module is configured to identify and process the second part of the laser to obtain a timing stop signal and send the timing stop signal to the high-precision timing circuit module. The high-precision timing circuit module is configured to calculate the time difference signal between the timing start signal and the timing stop signal and upload the time difference signal to the main control circuit module. The main control circuit module is configured to analyze and calculate the time difference signal to obtain the distance data.

[0037] Based on the corresponding functions of the above-mentioned unit modules, the laser ranging system provided by the embodiment of the present invention has the following main working process: The main control circuit module first receives the laser ranging instruction sent by the user, and drives the laser emission circuit module to emit laser towards the target to be measured based on the laser ranging instruction; a part of the laser is split by a beam splitter, reflected, and then recognized and processed by the optical sampling signal processing circuit, and enters the high-precision timing circuit module as a timing start signal (START signal); another part of the laser shoots towards the target to be measured, is reflected by the target to be measured, and then recognized and processed by the detection signal processing circuit module, and enters the high-precision timing circuit module as a timing stop signal (STOP signal); the high-precision timing circuit module calculates the time difference between the start and stop signals according to the received start and stop signals, uploads the time information to the main control circuit module through the SPI communication protocol, parses and calculates it into a distance value, and completes the measurement of the distance value of the target to be measured.

[0038] In an optional embodiment, the detection signal processing circuit module may further include a detector receiving circuit unit and a threshold comparison circuit unit. As Figure 2 shown, the threshold comparison circuit unit is communicatively connected to the detector receiving circuit unit and the high-precision timing circuit module respectively. The detector receiving circuit unit is used to receive and process the second part of the laser, obtain a laser analog signal, and send the laser analog signal to the threshold comparison circuit module; the threshold comparison circuit unit is used to perform threshold comparison on the laser analog signal to obtain a timing stop signal, and send the timing stop signal to the high-precision timing circuit module.

[0039] Specifically, the second part of the laser shoots towards the target to be measured, is reflected by the target to be measured, and then received and recognized by the detection receiving circuit unit. The detection receiving circuit unit performs detector amplification and filtering processing on the second part of the laser to obtain a laser analog signal, and sends the laser analog signal to the threshold comparison circuit unit. The threshold comparison circuit unit presets a threshold voltage, compares the voltage value corresponding to the laser analog signal with the preset threshold voltage value, and shapes and outputs a standard square wave digital signal into the high-precision timing circuit module, which is the timing stop signal (STOP signal).

[0040] In an optional embodiment, the main control circuit module uses an STM32 single-chip microcomputer.

[0041] Furthermore, the following explanation is given for the main control circuit module to analyze and calculate the time difference signal to obtain the distance data:

[0042] As Figure 3 shown, it is the echo waveform diagram of targets with different reflectivities at the same measurement distance. According to Figure 3 , the traditional rising edge trigger is used to calculate the distance error value of the target to be measured as shown in Equation (1).

[0043]

[0044] Among them, c is the propagation speed of light in the atmosphere; t 1u 、t 2u are respectively the rising-edge trigger moments of the shaped square-wave signals of different measured targets at the same measurement distance. It can be seen from Equation (1) that the error between the two distance measurement values is Δd, and the greater the change in the amplitude of the measured target, the greater the measurement error Δd, which affects the measurement accuracy of the same distance value.

[0045] The embodiment of the present utility model ingeniously applies the double-edge trigger function of the time measurement chip in the field of laser ranging, under the simultaneous triggering action of the rising edge and the falling edge. That is to say, in the embodiment of the present utility model, the main control circuit module powers on and initializes the configuration of the time measurement chip measurement mode to be triggered simultaneously by the rising edge and the falling edge.

[0046] According to Figure 3 , the distance values of the measured target obtained from the two measurements are respectively Equation (2) and Equation (3).

[0047]

[0048] Δd‘ = D1 - D2 = 0

[0049] Among them, c is the propagation speed of light in the atmosphere; t 1u 、t 2u are respectively the rising-edge trigger moments of the shaped square-wave signals of different measured targets at the same measurement distance; t 1d 、t 2d are respectively the falling-edge trigger moments of the shaped square-wave signals of different measured targets at the same measurement distance; t av is the median moment of the square-wave signal output by the measured target through the threshold control and comparison circuit module; D1 and D2 are respectively the distance data of the measured target obtained from the two measurements, and Δd' is the error value of the two measurement results.

[0050] Since the measurement mode of the embodiment of the present utility model is triggered simultaneously by the rising edge and the falling edge, the error value Δd' of the two measurement results is 0. Thus, the problem of measurement accuracy exceeding the standard caused by the change in the amplitude and pulse width of the echo signal of the measured target is solved.

[0051] In an optional embodiment, the main control circuit module uses an STM32F101C8T6 small-package single-chip microcomputer to control the operation of the entire laser ranging system. The high-precision timing circuit module uses a TDC-GP2 time measurement chip, and a 16 MHz high-frequency crystal oscillator is used as the clock source peripherally, and the rising edge and the falling edge of the START and STOP channels are set to be triggered simultaneously. The main control circuit module can also be used to perform register configuration on the TDC-GP2 time measurement chip in the high-precision timing circuit module, such as Figure 4As shown in the figure, it is a schematic flowchart of the STM32 controlling the TDC-GP2 for parameter configuration. Specifically, the register configuration is as follows:

[0052] REG0 = 0x80008528;

[0053] REG1 = 0x81214400;

[0054] REG2 = 0x82e80000;

[0055] REG3 = 0x83100000;

[0056] REG4 = 0x84200000;

[0057] REG5 = 0x85080000.

[0058] A laser ranging system provided by an embodiment of the present invention includes a main control circuit module, a laser emission circuit module, an optical sampling signal processing circuit module, a high-precision timing circuit module, and a detection signal processing circuit module; the main control circuit module is used to drive the laser emission circuit module to emit laser towards the target to be measured after receiving a laser ranging instruction; the first part of the laser is received by the optical sampling signal processing circuit module after being split and reflected by a beam splitter; the second part of the laser shoots towards the target to be measured and is received by the detection signal processing circuit module after being reflected; the optical sampling signal processing circuit module is used to identify and process the first part of the laser to obtain a timing opening signal and send the timing opening signal to the high-precision timing circuit module; the detection signal processing circuit module is used to identify and process the second part of the laser to obtain a timing closing signal and send the timing closing signal to the high-precision timing circuit module; the high-precision timing circuit module is used to calculate the time difference signal between the timing opening signal and the timing closing signal and upload the time difference signal to the main control circuit module; the main control circuit module is used to analyze and calculate the time difference signal to obtain distance data. The technical solution of the present invention realizes the convenience and miniaturization of the ranging circuit, and relies on the STM32 main control module and the high-precision timing circuit module to accurately measure the distance value of the target to be measured, reduce the influence of signal amplitude and pulse width on the ranging accuracy, and is successfully applied in an erbium glass pulsed miniature laser ranging system.

[0059] It can be understood that the same or similar parts in the above embodiments can be referred to each other, and the content not detailed in some embodiments can be seen in the same or similar content of other embodiments.

[0060] It should be noted that in the description of the present invention, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. In addition, in the description of the present invention, unless otherwise specified, the meaning of "a plurality of" refers to at least two.

[0061] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples", etc. means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present utility model. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0062] Although the embodiments of the present utility model have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present utility model. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present utility model.

Claims

1. A laser ranging system, characterized in that, It includes a main control circuit module, a laser emission circuit module, an optical sampling signal processing circuit module, a high-precision timing circuit module, and a detection signal processing circuit module; the laser emission circuit module and the high-precision timing circuit module are respectively communicatively connected to the main control circuit module; the optical sampling signal processing circuit module and the detection signal processing circuit module are respectively communicatively connected to the high-precision timing circuit module; The main control circuit module is used to drive the laser emission circuit module to emit laser towards the target to be measured after receiving a laser ranging instruction; the first part of the laser is received by the optical sampling signal processing circuit module after being split and reflected by a beam splitter; the second part of the laser is emitted towards the target to be measured and is received by the detection signal processing circuit module after being reflected; The optical sampling signal processing circuit module is used to identify and process the first part of the laser to obtain a timing opening signal, and send the timing opening signal to the high-precision timing circuit module; The detection signal processing circuit module is used to identify and process the second part of the laser to obtain a timing closing signal, and send the timing closing signal to the high-precision timing circuit module; The high-precision timing circuit module is used to calculate the time difference signal between the timing opening signal and the timing closing signal, and upload the time difference signal to the main control circuit module; The main control circuit module is used to analyze and calculate the time difference signal to obtain distance data.

2. The laser ranging system according to claim 1, wherein The detection signal processing circuit module includes a detector receiving circuit unit and a threshold comparison circuit unit; the threshold comparison circuit unit is respectively communicatively connected to the detector receiving circuit unit and the high-precision timing circuit module; The detector receiving circuit unit is used to receive and process the second part of the laser to obtain a laser analog signal, and send the laser analog signal to the threshold comparison circuit module; The threshold comparison circuit unit is used to perform threshold comparison on the laser analog signal to obtain a timing closing signal, and send the timing closing signal to the high-precision timing circuit module.

3. The laser ranging system according to claim 2, wherein The detector receiving circuit unit is also used to perform detector amplification and filtering processing on the second part of the laser to obtain the laser analog signal.

4. The laser ranging system according to claim 2, characterized in that, The threshold comparison circuit unit is also used to compare the laser analog signal with a preset threshold voltage value, and shape and output a standard square wave digital signal as the timing closing signal.

5. The laser ranging system according to claim 1, characterized in that, The main control circuit module powers on and initializes the configuration of the time measurement chip to trigger on both the rising edge and the falling edge.

6. The laser ranging system according to claim 5, characterized in that, The main control circuit module is also used to calculate the distance data using the following formula: Δd‘=D1-D2=0 Among them, c is the propagation speed of light in the atmosphere; t 1u , t 2u are respectively the rising edge trigger times of the shaped square wave signals of different measured targets at the same measurement distance; t 1d , t 2d are respectively the falling edge trigger times of the shaped square wave signals of different measured targets at the same measurement distance; t av is the median time of the square wave signal output by the measured target through the threshold control and comparison circuit module; D1 and D2 are respectively the distance data of the measured target in two measurements, and Δd' is the error value of the two measurement results.

7. The laser ranging system according to any one of claims 1 to 6, characterized in that, The main control circuit module uses an STM32 single-chip microcomputer.

8. The laser ranging system according to claim 7, characterized in that, The high-precision timing circuit module uses a TDC-GP2 time measurement chip, and a 16MHz high-frequency crystal oscillator is used as the clock source peripherally.

9. The laser ranging system according to claim 8, wherein, The main control circuit module is also used to perform register configuration on the TDC-GP2 time measurement chip in the high-precision timing circuit module.

10. The laser ranging system according to claim 1, characterized in that, The high-precision timing circuit module is also used to upload the time difference signal to the main control circuit module through the SPI communication protocol.

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