CN118795446B - Pulse signal preprocessing method and system - Google Patents
Pulse signal preprocessing method and system Download PDFInfo
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- G—PHYSICS
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- 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
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
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- 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
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- G06F3/05—Digital input using the sampling of an analogue quantity at regular intervals of time, input from a/d converter or output to d/a converter
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Abstract
本发明涉及信号处理技术领域，具体为一种脉冲信号预处理方法及系统，系统包括激光雷达模块、时钟电路、模数转换电路和FPGA处理模块，方法包括：通过模数转换电路接收雷达波模拟信号以及时钟电路产生的时钟信号，基于雷达波模拟信号和时钟信号生成数字采样波；通过FPGA处理模块确定数字采样波是否在预设的阈值范围内，若确定数字采样波的幅值在预设的阈值范围内，则确定数字采样波中数字发射波的峰值和数字反射波的峰值；通过FPGA处理模块确定数字发射波的峰值和数字反射波的峰值之间的时间差，基于时间差确定激光雷达模块的测量距离；本发明能够提高脉冲信号预处理的准确性。
The present invention relates to the field of signal processing technology, and specifically to a pulse signal preprocessing method and system. The system includes a laser radar module, a clock circuit, an analog-to-digital conversion circuit and an FPGA processing module. The method includes: receiving a radar wave analog signal and a clock signal generated by a clock circuit through the analog-to-digital conversion circuit, and generating a digital sampling wave based on the radar wave analog signal and the clock signal; determining whether the digital sampling wave is within a preset threshold range through the FPGA processing module, and if it is determined that the amplitude of the digital sampling wave is within the preset threshold range, determining the peak value of a digital transmission wave and the peak value of a digital reflection wave in the digital sampling wave; determining the time difference between the peak value of the digital transmission wave and the peak value of the digital reflection wave through the FPGA processing module, and determining the measurement distance of the laser radar module based on the time difference; the present invention can improve the accuracy of pulse signal preprocessing.
Description
Technical Field
The present invention relates to the field of signal processing technologies, and in particular, to a method and a system for preprocessing a pulse signal.
Background
In lidar systems, the raw data received is typically a series of pulse signals that are captured by a sensor and transmitted to a processing unit. The original pulse signal often carries a lot of noise and clutter due to environmental noise, scattering properties of the target object, etc. Therefore, these pulse signals need to be preprocessed to extract the target information and reject or suppress the noise signals, thereby improving the accuracy and efficiency of the subsequent processing.
In the related art, a filter is mainly adopted in the laser radar pulse signal preprocessing technology, noise signals are filtered through controlling the frequency characteristic of the filter, and target signals are reserved. However, conventional filter approaches may be difficult to accommodate in complex and varying environments and target characteristics, which may easily lead to signal distortion or information loss.
Disclosure of Invention
Accordingly, an objective of the embodiments of the present invention is to provide a method and a system for preprocessing a pulse signal, which solve one or more technical problems existing in the prior art, and provide at least one beneficial selection or creation condition.
In one aspect, an embodiment of the present invention provides a pulse signal preprocessing method, which is applied to a pulse signal preprocessing system, where the pulse signal preprocessing system includes a laser radar module, a clock circuit, an analog-to-digital conversion circuit, and an FPGA processing module, and the method includes the following steps:
Receiving a radar wave analog signal and a clock signal generated by the clock circuit through the analog-to-digital conversion circuit, and generating a digital sampling wave based on the radar wave analog signal and the clock signal, wherein the radar wave analog signal comprises an analog emission wave and an analog reflection wave, the digital sampling wave comprises a plurality of continuous sampling time periods and corresponding digital sampling values, the digital sampling values are generated based on the digital sampling wave, the sampling time periods are generated based on the clock signal, the digital sampling wave comprises a digital emission wave and a digital reflection wave, and the radar wave analog signal is generated based on a radar pulse wave signal output by a laser radar module;
determining whether the digital sampling wave is in a preset threshold range or not through the FPGA processing module, and if the amplitude of the digital sampling wave is determined to be in the preset threshold range, determining the peak value of the digital emission wave and the peak value of the digital reflection wave in the digital sampling wave;
and determining a time difference between the peak value of the digital emission wave and the peak value of the digital reflection wave through the FPGA processing module, and determining the measuring distance of the laser radar module based on the time difference.
Optionally, the generating a digital sampling wave based on the radar wave analog signal and the clock signal includes:
Acquiring a clock period of the clock signal;
The analog-to-digital conversion circuit is used for collecting the radar wave analog signals, and the time for collecting the radar wave analog signals by the analog-to-digital conversion circuit is divided into a plurality of continuous sampling time periods according to the clock period;
And converting the radar wave analog signal of each sampling time period into a corresponding digital sampling value, and taking a plurality of sampling time periods and the corresponding digital sampling values as the digital sampling waves.
Optionally, the determining the peak value of the digital emission wave and the peak value of the digital reflection wave in the digital sampling wave includes:
Screening digital sampling values with amplitude values within the threshold range in the digital sampling waves to obtain a sampling area containing a plurality of digital sampling values;
Taking 3 continuous sampling points as a group, traversing the digital sampling values in the sampling area, and selecting 3 continuous target sampling points, wherein the amplitude of the sampling point positioned in the middle of the 3 continuous target sampling points is the largest;
The peak value of the digital sampling wave is determined based on the 3 consecutive target sampling points.
Optionally, the pulse signal preprocessing system further includes a signal conditioning circuit, the signal conditioning circuit being connected between the lidar module and the analog-to-digital conversion circuit, the method further comprising:
And the signal regulating circuit receives the radar pulse wave signal output by the laser radar module, adjusts the gain of the radar pulse wave signal into a radar wave analog signal, and then sends the radar pulse wave analog signal to the analog-to-digital conversion circuit.
Optionally, after the determining, by the FPGA processing module, whether the digital sampling wave is within a preset threshold range, the method further includes:
When the digital sampling wave deviates from a preset threshold range, the gain coefficient of the numerical control variable gain amplifier is controlled by the FPGA processing module so as to adjust the radar pulse wave signal into a radar wave analog signal with the amplitude within the threshold range.
On the other hand, the embodiment of the invention provides a pulse signal preprocessing system, which comprises a laser radar module, a clock circuit, an analog-to-digital conversion circuit and an FPGA processing module;
The analog-to-digital conversion circuit is used for receiving a radar wave analog signal and a clock signal generated by the clock circuit and generating a digital sampling wave based on the radar wave analog signal and the clock signal, wherein the radar wave analog signal comprises an analog emission wave and an analog reflection wave, the digital sampling wave comprises a plurality of continuous sampling time periods and corresponding digital sampling values, the digital sampling values are generated based on the digital sampling wave, the sampling time periods are generated based on the clock signal, the digital sampling wave comprises a digital emission wave and a digital reflection wave, and the radar wave analog signal is generated based on a radar pulse wave signal output by the laser radar module;
The FPGA processing module is used for determining whether the digital sampling wave is in a preset threshold range, if so, determining the peak value of the digital emission wave and the peak value of the digital reflection wave in the digital sampling wave, further determining the time difference between the peak value of the digital emission wave and the peak value of the digital reflection wave, and determining the measuring distance of the laser radar module based on the time difference.
Optionally, the generating a digital sampling wave based on the radar wave analog signal and the clock signal includes:
Acquiring a clock period of the clock signal;
The analog-to-digital conversion circuit is used for collecting the radar wave analog signals, and the time for collecting the radar wave analog signals by the analog-to-digital conversion circuit is divided into a plurality of continuous sampling time periods according to the clock period;
And converting the radar wave analog signal of each sampling time period into a corresponding digital sampling value, and taking a plurality of sampling time periods and the corresponding digital sampling values as the digital sampling waves.
Optionally, the determining the peak value of the digital emission wave and the peak value of the digital reflection wave in the digital sampling wave includes:
Screening digital sampling values with amplitude values within the threshold range in the digital sampling waves to obtain a sampling area containing a plurality of digital sampling values;
Taking 3 continuous sampling points as a group, traversing the digital sampling values in the sampling area, and selecting 3 continuous target sampling points, wherein the amplitude of the sampling point positioned in the middle of the 3 continuous target sampling points is the largest;
The peak value of the digital sampling wave is determined based on the 3 consecutive target sampling points.
Optionally, the pulse signal preprocessing system further comprises a signal adjusting circuit, wherein the signal adjusting circuit is connected between the laser radar module and the analog-to-digital conversion circuit;
The signal regulating circuit is used for receiving the radar pulse wave signal output by the laser radar module, regulating the gain of the radar pulse wave signal into a radar wave analog signal and then sending the radar pulse wave analog signal to the analog-to-digital conversion circuit.
Optionally, the FPGA processing module is further configured to:
When the digital sampling wave deviates from a preset threshold range, the gain coefficient of the numerical control variable gain amplifier is controlled by the FPGA processing module so as to adjust the radar pulse wave signal into a radar wave analog signal with the amplitude within the threshold range.
The method has the advantages that in the method, an analog-to-digital conversion circuit is used for converting a radar wave analog signal into a digital sampling wave, an original signal waveform can be reserved, an FPGA processing module is used for comparing the digital sampling wave with a preset threshold range, the amplitude of the digital sampling wave is adjusted to be within the threshold range by adjusting the gain of a radar pulse wave signal, and a data processing module is used for processing the peak value of a digital transmitting wave and the peak value of the digital reflecting wave, so that the measuring distance of a laser radar module can be rapidly and accurately determined. The invention can improve the accuracy of the pretreatment of the pulse signals.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions of the prior art, the drawings that are needed in the embodiments will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
Fig. 1 is a schematic flow chart of steps of a pulse signal preprocessing method according to an embodiment of the present invention;
FIG. 2 is a block diagram of a pulse signal preprocessing system according to an embodiment of the present invention;
FIG. 3 is a waveform diagram of a radar wave analog signal in an embodiment of the present invention;
fig. 4 is a sample graph of a digital sample wave in an embodiment of the invention.
Detailed Description
The present application will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present application more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the application.
It should be noted that although block division is performed in the apparatus schematic, a logic sequence is shown in the flowchart, in some cases, the steps shown or described may be performed in a different order than the block division in the apparatus, or in the flowchart. The terms first, second and the like in the description and in the claims and in the above-described figures, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing embodiments of the application only and is not intended to be limiting of the application.
Furthermore, the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to give a thorough understanding of embodiments of the application. One skilled in the relevant art will recognize, however, that the application may be practiced without one or more of the specific details, or with other methods, components, devices, steps, etc. In other instances, well-known methods, devices, implementations, or operations are not shown or described in detail to avoid obscuring aspects of the application.
The block diagrams depicted in the figures are merely functional entities and do not necessarily correspond to physically separate entities. That is, these functional entities may be implemented in software, or in one or more hardware charging modules or integrated circuits, or in different networks and/or processor devices and/or microcontroller devices.
The flow diagrams depicted in the figures are exemplary only, and do not necessarily include all of the elements and operations/steps, nor must they be performed in the order described. For example, some operations/steps may be decomposed, and some operations/steps may be combined or partially combined, so that the order of actual execution may be changed according to actual situations.
The following first explains several technical terms related to the present invention;
FPGA processing module, field-Programmable GATE ARRAY (Field Programmable gate array);
Analog-to-digital converter (Analog-to-digital converter);
SPI SERIAL PERIPHERAL INTERFACE (serial peripheral interface);
LVDS: low-Voltage DIFFERENTIAL SIGNALING (Low Voltage differential Signal);
In the related art, an analog signal received by a laser radar often has a relatively high frequency and a relatively high dynamic range, and the analog signal can be processed and analyzed in the digital field only by being converted by an analog-to-digital conversion circuit chip. The performance of the analog-to-digital conversion circuit chip directly influences important indexes such as sampling precision, signal-to-noise ratio and power consumption of the system.
The analog-to-digital conversion circuit chip has higher sampling rate and resolution, can accurately convert an analog signal into a digital signal, and retains the original waveform characteristics of the signal.
Based on the above, in order to solve the technical problems in the background technology, the invention provides a pulse signal preprocessing method and a pulse signal preprocessing system, which realize the rapid and accurate conversion from an analog signal to a digital signal by adopting an analog-to-digital conversion circuit chip and provide a reliable data basis for the subsequent digital signal processing. The FPGA processing module is used for processing digital signals, so that high-performance and low-delay real-time data processing can be realized, and reliable data support is provided for follow-up.
As shown in fig. 1 and fig. 2, the pulse signal preprocessing method provided by the embodiment of the invention is applied to a pulse signal preprocessing system, wherein the pulse signal preprocessing system comprises a laser radar module, a clock circuit, an analog-to-digital conversion circuit and an FPGA processing module, and the method comprises the following steps:
S100, receiving a radar wave analog signal and a clock signal generated by a clock circuit through an analog-to-digital conversion circuit, and generating a digital sampling wave based on the radar wave analog signal and the clock signal, wherein the radar wave analog signal comprises an analog emission wave and an analog reflection wave, the digital sampling wave comprises a plurality of continuous sampling time periods and corresponding digital sampling values, the digital sampling values are generated based on the digital sampling wave, and the sampling time periods are generated based on the clock signal;
S200, determining whether the digital sampling wave is in a preset threshold range or not through an FPGA processing module, and if the amplitude of the digital sampling wave is determined to be in the preset threshold range, determining the peak value of the digital emission wave and the peak value of the digital reflection wave in the digital sampling wave;
S300, determining a time difference between the peak value of the digital emission wave and the peak value of the digital reflection wave through the FPGA processing module, and determining the measuring distance of the laser radar module based on the time difference.
In the embodiment provided by the invention, the pulse signal preprocessing circuit is used for converting a radar wave analog signal into a stable digital signal, the pulse signal preprocessing circuit comprises a signal adjusting circuit, a clock circuit, an analog-to-digital conversion circuit and an FPGA processing module, the signal adjusting circuit is used for adjusting the signal by using a numerical control variable gain amplifier with the model of LMH6521SQ/NOPB, the clock circuit is used for generating an LVDS clock signal by using a clock generator with the model of CDCE62002 chip to provide an LVDS clock signal for an MXT2001E chip, the analog-to-digital conversion circuit is used for converting the radar wave analog signal into the digital signal by using the MXT2001E chip, and the FPGA processing module is responsible for preprocessing data.
Specifically, the FPGA processing module configures an analog-to-digital conversion circuit to be in a DDR mode or an SDR mode through an SPI interface, for example, the speed of a radar wave analog signal is 1/2 of that of an input clock in the single data rate SDR mode, the speed of the radar wave analog signal is 1/4 of that of the input clock in the double data rate DDR mode, the analog-to-digital conversion circuit needs to be sampled by the clock, a clock circuit (the FPGA processing module configuration) is added to the input end of the analog-to-digital conversion circuit, the situation that the radar wave analog signal is possibly too large or too small is considered, a signal regulating circuit is arranged at the front end of the analog-to-digital conversion circuit, the radar wave analog signal is possibly not considered to be an obstacle echo, rain fog or water drops and the like, and the radar wave analog signal is too large to cause a test error.
In this embodiment, the analog-to-digital conversion circuit receives the radar wave analog signal output by the lidar module and converts the radar wave analog signal into a digital signal, so as to facilitate subsequent digital signal processing. The analog-to-digital conversion circuit adopts an SPI interface and an LVDS interface to communicate with the FPGA processing module, and can accurately convert the radar wave analog signal into a digital signal and retain the original signal waveform. The FPGA processing module is used for receiving the digital signals output by the analog-to-digital conversion circuit, calculating and processing the digital signals to obtain a measurement distance, and dividing the measurement distance by 2 after multiplying the time difference and the transmission rate of the radar wave to obtain the measurement distance of the laser radar module.
As shown in fig. 3 and 4, in some embodiments, generating a digital sampling wave based on a radar wave analog signal and a clock signal includes:
s110, acquiring a clock period of a clock signal;
s120, acquiring radar wave analog signals through an analog-to-digital conversion circuit, and dividing the time for acquiring the radar wave analog signals by the analog-to-digital conversion circuit into a plurality of continuous sampling time periods according to a clock period;
S130, converting the radar wave analog signal of each sampling time period into a corresponding digital sampling value, and taking a plurality of sampling time periods and the corresponding digital sampling value as digital sampling waves.
In the embodiment provided by the invention, the sampling time period is divided by using the clock period of the clock signal, so that the accuracy and consistency of sampling can be ensured, and the accuracy of analog-to-digital conversion is improved. The clock signal and the radar wave analog signal are used for synchronous sampling, so that the corresponding relation between the sampling waveform and the original signal in time can be ensured, and phase errors in the sampling process are avoided. The sampling rate can be flexibly changed by adjusting the clock period, the radar wave analog signals with different frequency characteristics are adapted, and the requirements of different application scenes are met. The sampling time periods are in one-to-one correspondence with the corresponding digital sampling values, so that the integrity and consistency of data are ensured, and the subsequent data processing and analysis are facilitated. By converting the radar wave analog signal into a digital sampled wave, the digital sampled wave can be efficiently analyzed and processed using digital signal processing techniques.
In some embodiments, determining the peak value of the digital transmit wave and the peak value of the digital reflected wave in the digital sample wave comprises:
S210, screening digital sampling values with amplitude values within the threshold range in the digital sampling wave to obtain a sampling area containing a plurality of digital sampling values;
S220, traversing the digital sampling values in the sampling area by taking 3 continuous sampling points as a group, and selecting 3 continuous target sampling points, wherein the amplitude of the sampling point positioned in the middle of the 3 continuous target sampling points is the largest;
and S230, determining the peak value of the digital sampling wave based on the 3 continuous target sampling points.
Referring to fig. 3, the object for which the threshold range in fig. 3 is aimed is a digital sampling wave generated from the radar wave analog signal, and since the amplitude of the radar wave analog signal is the same as that of the digital sampling wave, the threshold range is superimposed on the radar wave analog signal for visual presentation.
Specifically, the amplitude of the sampling point located in the middle of 3 consecutive target sampling points is taken as the peak value of the digital sampling wave;
or using a polynomial to fit the digital sampling values in the sampling area to obtain a fitting polynomial, calculating the derivative of the fitting polynomial, taking the digital sampling values with zero derivative as potential peak points, and taking the maximum value of each potential peak point in the digital sampling wave as the peak value of the digital sampling wave.
In the embodiment, the peak value of the digital sampling wave is determined by adopting the highest point and two sampling points adjacent to the highest point, so that the accuracy can be ensured, and the calculated amount and the calculated time are greatly reduced. Specifically, a sampling area containing a peak is selected, the sampling area comprises 3 continuous sampling points in a threshold range, and the amplitude of the sampling point located in the middle is the largest in the area containing the peak, so that the area possibly containing the peak can be screened out. The maximum value in the amplitude values of 3 continuous target sampling points is approximately regarded as the peak value of the digital sampling wave, so that the peak value point is quickly determined, or the peak value point is determined in a polynomial fitting mode, so that the peak value point is accurately determined. The embodiment provided by the invention can adapt to different signal characteristics, and can effectively determine the peak value whether the signal is a smooth signal or a signal with noise. The method has certain robustness to noise and abnormal values in the data, and can provide stable peak value estimation.
In some embodiments, the pulse signal preprocessing system further comprises a signal conditioning circuit connected between the laser radar module and the analog-to-digital conversion circuit, the method further comprising:
The radar pulse wave signal output by the laser radar module is received through the signal adjusting circuit, and the gain of the radar pulse wave signal is adjusted to be a radar wave analog signal and then sent to the analog-to-digital conversion circuit.
In this embodiment, the signal adjusting circuit performs variable gain amplification or reduction on the radar pulse wave signal, so that the amplitude of the received radar pulse signal can be adjusted to adapt to different signal intensities and noise levels, so as to facilitate improvement of the accuracy and efficiency of pulse signal preprocessing. It will be appreciated that the radar pulse wave signal received by the signal conditioning circuit is an analog signal, and the output is also a radar wave analog signal.
In some embodiments, after determining, by the FPGA processing module, whether the digital sampled wave is within the preset threshold range, further comprising:
When the digital sampling wave deviates from a preset threshold range, the gain coefficient of the numerical control variable gain amplifier is controlled by the FPGA processing module so as to adjust the radar pulse wave signal into a radar wave analog signal with the amplitude within the threshold range.
In this embodiment, by comparing the digital sampling wave with a preset threshold range, the distorted radar wave analog signal is removed, and the subsequent erroneous measurement distance is avoided. It should be noted that the echo may not be an obstacle, may be rain fog, water drops, etc., and if the digital sampling wave deviates from the threshold range, the digital sampling wave is not analyzed after being sent to the FPGA processing module, but the next digital sampling wave is received until the digital sampling wave within the threshold range is received. If the peak point in the digital sampling wave obtained after amplification and two adjacent points thereof are close, or the peak point in the digital sampling wave is larger than the maximum output value of the ADC, judging that the measured distance has errors, and re-receiving the radar wave analog signal.
If the digital sampling waves received for multiple times deviate from the threshold range, the fact that the amplitude of the radar wave analog signal obtained through radar pulse wave signal adjustment is difficult to meet the requirement is indicated, the gain coefficient of the numerical control variable gain amplifier is controlled through the FPGA processing module, the digital sampling waves with the amplitude in the threshold range can be obtained, therefore, effective peaks are obtained, and accurate ranging is achieved.
Specifically, when the radar wave analog signal is too large, assuming that the data bit width output by the analog-to-digital conversion circuit is 8 bits, the maximum value of the threshold range is 2^8, namely 255, and the potential peak point and two adjacent points thereof are used as 3 continuous sampling points:
in the first case, the values of the 3 continuous sampling points are all larger than or equal to 255, the maximum value cannot be determined, and the measurement distance cannot be calculated.
In the second case, the first sampling point is greater than or equal to 255, the second sampling point is greater than, equal to or less than 255, and the third sampling point is smaller than 255, so that the maximum value cannot be determined, and the measurement distance cannot be calculated.
In the third case, the first sampling point is larger than the threshold value and smaller than 255, the second sampling point is larger than or equal to 255, the third sampling point is smaller than 255, and the calculated measurement distance has errors.
Under the three conditions, the FPGA processing module controls the numerical control variable gain amplifier to adjust the gain of the radar pulse wave signal, and the amplitude of the obtained radar wave analog signal is within the threshold range, so that the digital sampling wave is ensured to be within the threshold range.
Referring again to fig. 2, the embodiment of the invention provides a pulse signal preprocessing system, which comprises a laser radar module, a clock circuit, an analog-to-digital conversion circuit and an FPGA processing module;
the system comprises a laser radar module, an analog-to-digital conversion circuit, a digital sampling circuit and a digital sampling circuit, wherein the analog-to-digital conversion circuit is used for receiving a radar wave analog signal and a clock signal generated by the clock circuit and generating a digital sampling wave based on the radar wave analog signal and the clock signal, the radar wave analog signal comprises an analog emission wave and an analog reflection wave, the digital sampling wave comprises a plurality of continuous sampling time periods and corresponding digital sampling values, the digital sampling values are generated based on the digital sampling wave, and the sampling time periods are generated based on the clock signal;
The FPGA processing module is used for determining whether the digital sampling wave is in a preset threshold range, if the amplitude of the digital sampling wave is determined to be in the preset threshold range, determining the peak value of the digital transmitting wave and the peak value of the digital reflecting wave in the digital sampling wave, further determining the time difference between the peak value of the digital transmitting wave and the peak value of the digital reflecting wave, and determining the measuring distance of the laser radar module based on the time difference.
It can be seen that the content in the above method embodiment is applicable to the system embodiment, and the functions specifically implemented by the system embodiment are the same as those of the method embodiment, and the beneficial effects achieved by the method embodiment are the same as those achieved by the method embodiment.
Referring again to fig. 3 and 4, in some embodiments, generating a digital sampling wave based on a radar wave analog signal and a clock signal includes:
Acquiring a clock period of a clock signal;
The method comprises the steps that an analog-to-digital conversion circuit is used for collecting radar wave analog signals, and the time for the analog-to-digital conversion circuit to collect the radar wave analog signals is divided into a plurality of continuous sampling time periods according to clock cycles;
the radar wave analog signal of each sampling time period is converted into a corresponding digital sampling value, and a plurality of sampling time periods and the corresponding digital sampling values are used as digital sampling waves.
In the embodiment provided by the invention, the sampling time period is divided by using the clock period of the clock signal, so that the accuracy and consistency of sampling can be ensured, and the accuracy of analog-to-digital conversion is improved. The clock signal and the radar wave analog signal are used for synchronous sampling, so that the corresponding relation between the sampling waveform and the original signal in time can be ensured, and phase errors in the sampling process are avoided. The sampling rate can be flexibly changed by adjusting the clock period, the radar wave analog signals with different frequency characteristics are adapted, and the requirements of different application scenes are met. The sampling time periods are in one-to-one correspondence with the corresponding digital sampling values, so that the integrity and consistency of data are ensured, and the subsequent data processing and analysis are facilitated. By converting the radar wave analog signal into a digital sampled wave, the signal can be efficiently analyzed and processed using digital signal processing techniques.
In some embodiments, determining the peak value of the digital transmit wave and the peak value of the digital reflected wave in the digital sample wave comprises:
Screening digital sampling values with amplitude values within the threshold range in the digital sampling waves to obtain a sampling area containing a plurality of digital sampling values;
Taking 3 continuous sampling points as a group, traversing the digital sampling values in the sampling area, and selecting 3 continuous target sampling points, wherein the amplitude of the sampling point positioned in the middle of the 3 continuous target sampling points is the largest;
The peak value of the digital sampling wave is determined based on the 3 consecutive target sampling points.
In some embodiments, the pulse signal preprocessing system further comprises a signal conditioning circuit connected between the laser radar module and the analog-to-digital conversion circuit;
The signal adjusting circuit is used for receiving the radar pulse wave signal output by the laser radar module, adjusting the gain of the radar pulse wave signal into a radar wave analog signal and sending the radar wave analog signal to the analog-to-digital conversion circuit.
In this embodiment, the signal adjusting circuit performs variable gain amplification on the radar pulse wave signal, so that the amplitude of the received radar pulse signal can be adjusted to adapt to different signal intensities and noise levels, so as to facilitate improvement of the accuracy and efficiency of pulse signal preprocessing.
In some embodiments, the FPGA processing module is further to:
When the digital sampling wave deviates from a preset threshold range, the gain coefficient of the numerical control variable gain amplifier is controlled by the FPGA processing module so as to adjust the radar pulse wave signal into a radar wave analog signal with the amplitude within the threshold range.
In this embodiment, by comparing the digital sampling wave with a preset threshold range, the distorted radar wave analog signal is removed, and the subsequent erroneous measurement distance is avoided.
Those of ordinary skill in the art will appreciate that all or some of the steps of the methods, systems, functional charging modules/units in the devices disclosed above may be implemented as software, firmware, hardware, and suitable combinations thereof.
The terms "first," "second," "third," "fourth," and the like in the description of the application and in the above figures, if any, are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged where appropriate such that the embodiments of the application described herein may be implemented in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
It should be understood that in the present application, "at least one (item)" means one or more, and "a plurality" means two or more. "and/or" is used to describe an association relationship of an associated object, and indicates that three relationships may exist, for example, "a and/or B" may indicate that only a exists, only B exists, and three cases of a and B exist simultaneously, where a and B may be singular or plural. The character "/" generally indicates that the context-dependent object is an "or" relationship. "at least one of" or the like means any combination of these items, including any combination of single item(s) or plural items(s). For example, at least one of a, b or c may represent a, b, c, "a and b", "a and c", "b and c", or "a and b and c", wherein a, b, c may be single or plural.
In the several embodiments provided by the present application, it should be understood that the disclosed apparatus and method may be implemented in other manners. For example, the apparatus embodiments described above are merely illustrative, e.g., the division of the units is merely a logical function division, and there may be additional divisions when actually implemented, e.g., multiple units or components may be combined or integrated into another system, or some features may be omitted or not performed. Alternatively, the coupling or direct coupling or communication connection shown or discussed with each other may be an indirect coupling or communication connection via some interfaces, devices or units, which may be in electrical, mechanical or other form.
The units described as separate units may or may not be physically separate, and units shown as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.
In addition, each functional unit in the embodiments of the present application may be integrated in one processing unit, or each unit may exist alone physically, or two or more units may be integrated in one unit. The integrated units may be implemented in hardware or in software functional units.
The integrated units, if implemented in the form of software functional units and sold or used as stand-alone products, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present application may be embodied in essence or a part contributing to the prior art or all or part of the technical solution in the form of a software product stored in a storage medium, including multiple instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method according to the embodiments of the present application. The storage medium includes various media capable of storing programs, such as a U disk, a removable hard disk, a Read-Only Memory (ROM), a random access Memory (Random Access Memory RAM), a magnetic disk, or an optical disk.
The preferred embodiments of the present application have been described above with reference to the accompanying drawings, and are not thereby limiting the scope of the claims of the embodiments of the present application. Any modifications, equivalent substitutions and improvements made by those skilled in the art without departing from the scope and spirit of the embodiments of the present application shall fall within the scope of the claims of the embodiments of the present application.
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