A traffic radar speed measurement method, device, radar and readable storage medium

Abstract

The present invention relates to the technical field of radar speed measurement, and provides a traffic radar speed measurement method, device, radar and readable storage medium. Among them, the traffic radar speed measurement method includes the following steps: obtaining an echo signal of a target vehicle, and performing mixing and quadrature processing on the obtained echo signal and transmitted signal to obtain two characteristic signals of the target vehicle; sampling the obtained characteristic signals according to a predetermined number of sampling points, and performing analog-to-digital conversion on the sampled signals; performing anti-interference and arithmetic transformation processing on the obtained digital signals to extract the target signal spectrum of the target vehicle; correcting the obtained target signal spectrum through a spectrum correction algorithm to filter out sine signals in the target signal spectrum; according to the proportional relationship between speed and frequency in the Doppler dimension, calculating the speed of the target vehicle through the corrected target signal spectrum; the present invention can reduce the influence of signal delay, signal transient response, etc., and improve the response speed of radar speed measurement.

Description

Technical Field

[0001] The present invention relates to the technical field of radar speed measurement, and in particular, to a traffic radar speed measurement method, device, radar, and readable storage medium. Background Art

[0002] With the development of signal processing technology, the method of radar speed measurement has become increasingly mature, and the use of radar to measure the speed of moving vehicles in traffic control to determine whether the vehicle is speeding has also been more and more widely applied. In the current radar speed measurement method, usually, the received radio wave signal is subjected to Fourier transform and then passed through a filter to eliminate the interference of the sine signal to ensure the accuracy of speed measurement. However, when measuring speed by radar, usually multiple lanes are measured simultaneously, and multiple signals are collected for each vehicle, resulting in a large amount of signal processing by the radar. Using a filter to eliminate the sine signal interference will cause effects such as signal delay and signal transient response, thus affecting the response speed of radar speed measurement. Summary of the Invention

[0003] The problem solved by the present invention is how to reduce the effects such as signal delay and signal transient response that occur when eliminating the sine signal interference when the data processing volume is large, so as to improve the response speed of radar speed measurement.

[0004] To solve the above problems, in a first aspect, the present invention provides a traffic radar speed measurement method, including the following steps:

[0005] Obtain the echo signal of the target vehicle, and perform mixing and orthogonal processing on the obtained echo signal and the transmitted signal to obtain two characteristic signals of the target vehicle; wherein, the two characteristic signals are the orthogonal components of the echo signal of the target vehicle;

[0006] Sample the obtained characteristic signals according to a predetermined number of sampling points, and perform analog-to-digital conversion on the sampled signals to convert the sampled signals from wavelength signals to digital signals;

[0007] Perform anti-interference and arithmetic transformation processing on the obtained digital signals to extract the target signal spectrum of the target vehicle;

[0008] Perform correction on the obtained target signal spectrum through a spectrum correction algorithm to filter out the sine signal in the target signal spectrum;

[0009] According to the proportional relationship between speed and frequency in the Doppler dimension, calculate the speed of the target vehicle through the corrected target signal spectrum.

[0010] Optionally, before sampling the obtained characteristic signals according to a predetermined number of sampling points, the following steps are further included:

[0011] Perform three - stage filtering and amplification processing on the two paths of the feature signals. Among them, the first - stage filtering and amplification processing and the second - stage filtering and amplification processing are respectively used to process short - distance data and long - distance data, and the filtering and amplification multiple of the third - stage filtering and amplification processing is suitable for being adjusted.

[0012] Optionally, the obtaining of the echo signal of the target vehicle includes:

[0013] Transmit a radio - wave signal to the target road, and the transmitted radio - wave signal can cover each lane of the target road within a given range simultaneously;

[0014] Receive the echo signals reflected by the vehicles entering the radio - wave signal coverage range on the target road respectively. Among them, the received echo signals include the echo signals reflected by all vehicles within the radio - wave signal coverage range and the echo signals reflected by the vehicles in each single lane separately.

[0015] Optionally, the processing of the obtained digital signal for anti - interference and operation transformation to extract the target signal spectrum of the target vehicle includes:

[0016] Perform DC filtering operation on the digital signal to restore the signal deviation that may occur during the signal sampling process;

[0017] Perform operation on the digital signal after DC filtering through the Hanning window function to eliminate the interference of high - frequency signals and obtain the frequency, amplitude and initial phase angle of the sine signal in the digital signal;

[0018] Perform transformation on the digital signal after the Hanning window operation through the FFT algorithm to obtain the target signal spectrum in the digital signal.

[0019] Optionally, the performing of the DC filtering operation on the digital signal includes:

[0020] Calculate the average value of the data of the sampling signals with a given number of sampling points, and then subtract the average value from the value of each sampling signal, so as to correct the sampled signal and restore the signal deviation caused during the signal sampling process.

[0021] Optionally, the spectrum correction algorithm is the ratio correction method, and the correction of the obtained target signal spectrum through the spectrum correction algorithm includes:

[0022] Calculate the sine signal according to the amplitude, frequency and initial phase angle of the sine signal in the target signal spectrum;

[0023] Simulate a simulated sine signal according to the amplitude, frequency and initial phase angle of the sine signal in the target signal spectrum;

[0024] Obtain the target signal after eliminating the sine signal according to the difference between the sine signal and the simulated sine signal.

[0025] Optionally, after sampling the obtained characteristic signal according to the established number of sampling points, the following steps are further included:

[0026] Encrypt the important data in the sampled signal by using the address offset method.

[0027] Compared with the prior art, the present invention obtains the echo signal of the target vehicle, and performs mixing orthogonal processing on the obtained echo signal and the transmitted signal, so as to obtain two characteristic signals in orthogonal components, and the characteristic signals are intermediate frequency signals; then sample the obtained characteristic signal according to the established number of sampling points. Since the characteristic signal is an intermediate frequency signal, the stability of signal sampling can be improved. The signal after sampling is converted into a digital signal through analog-to-digital conversion for subsequent continuous processing of the signal; then perform anti-interference processing on the digital signal to eliminate the interference of unnecessary signals, improve the accuracy of subsequent signal processing, and perform arithmetic transformation processing on the digital signal to obtain the target signal spectrum in the signal of the target vehicle for calculating the speed of the target vehicle; then correct the obtained target signal spectrum through the spectrum correction algorithm to filter out the sine signal in the target signal spectrum, so as to replace the use of a filter to eliminate the interference of the sine signal in the prior art through the correction algorithm; then calculate the speed of the target vehicle according to the corrected target signal spectrum; this method improves the stability of signal sampling by performing mixing orthogonal processing on the signal, then performs anti-interference processing and arithmetic transformation processing on the converted digital signal to initially reduce the interference of clutter on the signal, and then filters out the interference of the sine signal in the signal through the spectrum correction method, mainly by performing arithmetic correction processing to filter out the interference factors in the signal, avoiding the use of a filter, so as to effectively reduce the signal delay, signal transient response, etc. that occur when eliminating the interference of the sine signal when the data processing volume is large, thereby improving the response speed of radar speed measurement.

[0028] In a second aspect, the present invention further provides a traffic radar speed measurement device, including:

[0029] An acquisition module: configured to acquire the echo signal of the target vehicle, and perform mixing orthogonal processing on the acquired echo signal and the transmitted signal to obtain two characteristic signals of the target vehicle; wherein, the two characteristic signals are orthogonal components of the echo signal of the target vehicle.

[0030] A sampling module: configured to sample the obtained characteristic signal according to the established number of sampling points, and perform analog-to-digital conversion on the sampled signal to convert the sampled signal from a wavelength signal to a digital signal.

[0031] Processing module: configured to perform anti-interference and arithmetic transformation processing on the obtained digital signal to extract the target signal spectrum of the target vehicle;

[0032] Calibration module: configured to calibrate the obtained target signal spectrum through a spectrum calibration algorithm to filter out sine signals in the target signal spectrum;

[0033] Calculation module: configured to calculate the speed of the target vehicle based on the proportional relationship between speed and frequency in the Doppler dimension through the calibrated target signal spectrum.

[0034] Thus, the traffic radar speed measurement device is used to implement the above traffic radar speed measurement method, and thus has at least all the technical effects of the above traffic radar speed measurement method.

[0035] In a third aspect, the present invention further provides a traffic speed measurement radar, including a radio frequency device, a transmitting antenna, a receiving antenna, a filtering and amplifying module, a processor, and a memory. The radio frequency device is electrically connected to the transmitting antenna and is configured to transmit a signal with a set frequency and cover the transmitted signal to a predetermined range of a target road through the transmitting antenna; the receiving antenna, the radio frequency device, the filtering and amplifying module, and the processor are sequentially electrically connected. The receiving antenna receives the echo signal of the vehicle in the target road, and the radio frequency device and the filtering and amplifying circuit sequentially perform mixing and quadrature processing and filtering and amplifying processing on the echo signal and then transmit it to the processor;

[0036] The receiving antenna includes a high-gain antenna and a small-angle antenna. The high-gain antenna is configured to receive the echo signal of the vehicle in the entire target road, and the small-angle antenna is configured to receive the echo signal of the vehicle in each single lane in the target road;

[0037] The memory stores computer-executable instructions, and when the computer-executable instructions are executed by the processor, the above traffic radar speed measurement method is implemented.

[0038] Thus, since the technical solution of the traffic speed measurement radar at least includes all the technical solutions of the above traffic radar speed measurement method, it thus has at least all the technical effects of the above traffic radar speed measurement method.

[0039] In a fourth aspect, the present invention further provides a computer-readable storage medium, which stores a computer program, and when the computer program is read and run by a processor, the above traffic radar speed measurement method is implemented.

[0040] Thus, since the technical solution of the computer-readable storage medium at least includes all the technical solutions of the above traffic radar speed measurement method, it thus has at least all the technical effects of the above traffic radar speed measurement method. Description of the Drawings

[0041] Figure 1 The structural connection diagram of the traffic speed measurement radar according to the embodiment of the present invention;

[0042] Figure 2 The flow chart of the traffic radar speed measurement method according to the embodiment of the present invention;

[0043] Figure 3 The structural connection diagram of the traffic radar speed measurement device according to the embodiment of the present invention.

[0044] Explanation of reference numerals: 1 - acquisition module; 2 - sampling module; 3 - processing module; 4 - calibration module; 5 - calculation module. Detailed implementation manners

[0045] In order to make the above objects, features and advantages of the present invention more obvious and understandable, the following detailed description of the specific embodiments of the present invention will be given with reference to the accompanying drawings.

[0046] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and do not necessarily need to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein.

[0047] In the description of the present invention, it should be noted that unless otherwise clearly defined and limited, the terms "set", "installed", "connected", "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0048] In the description of this specification, the descriptions referring to terms such as "embodiment", "one embodiment" and "one implementation manner" mean that the specific features, structures, materials or characteristics described in connection with the embodiment or implementation manner are included in at least one embodiment or implementation manner of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or implementation manner. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or implementation manners. To solve the above problems, such as Figure 1As shown in the figure, an embodiment of the present invention provides a traffic speed measurement radar, which includes a radio frequency device, a transmitting antenna, a receiving antenna, a filtering and amplifying module, a processor, and a memory. The radio frequency device is electrically connected to the transmitting antenna and is used to transmit a signal with a set frequency and cover the transmitted signal to a predetermined range of a target road through the transmitting antenna. The receiving antenna, the radio frequency device, the filtering and amplifying module, and the processor are electrically connected in sequence. The receiving antenna receives the echo signal of the vehicle in the target road, and the radio frequency device and the filtering and amplifying circuit perform mixing and quadrature processing and filtering and amplifying processing on the echo signal in sequence and then transmit it to the processor;

[0049] The receiving antenna includes a high-gain antenna and a small-angle antenna. The high-gain antenna is used to receive the echo signal of the vehicle in the entire target road, and the small-angle antenna is used to receive the echo signal of the vehicle in each single lane in the target road;

[0050] The memory stores computer-executable instructions, and when the computer-executable instructions are executed by the processor, a traffic radar speed measurement method is implemented.

[0051] It should be noted that the traffic speed radar can be installed at the edge of the road with an installation height of 2m. At this time, the radar is installed perpendicular to the road surface. The radar can also be installed inside a billboard or on an overpass. At this time, the height of the radar is generally 6m. At this time, the radar should be tilted 3° towards the road surface to ensure the detection range of the radar. The radar emits radio waves through a radio frequency device and covers the radio waves to the target road through a transmitting antenna. The installation height and angle of the radar determine the coverage range of the radio waves on the target road. The speed measurement range meets the requirement that vehicles in all lanes on the target road can enter the detection range and be effectively collected for echo signals. The set frequency of the emitted radio waves is 24GHz, and the radio frequency device can use the Infineon radio frequency chip BG24LTR11. When a vehicle on the target road enters the detection range of the radar, it will reflect the radio wave signal back and be received by the receiving antenna. The receiving antenna is electrically connected to the radio frequency device, so as to transmit the received echo signal to the radio frequency device, and the echo signal is subjected to mixing and quadrature processing with the transmitted signal in the radio frequency device to obtain two characteristic signals of the target vehicle. The radio frequency device is electrically connected to the filter amplification module, so as to transmit the two characteristic signals to the filter amplification module, and the filter amplification module performs three-stage filter amplification processing on the two characteristic signals. Among them, the filter amplification module includes a first-stage filter amplification sub-module, a second-stage filter amplification sub-module and a third-stage filter amplification sub-module. The first-stage filter amplification sub-module and the second-stage filter amplification sub-module can respectively filter and amplify the clutter of the characteristic signals in different frequency bands for processing short-distance data and long-distance data. The filtering range and amplification range of the third-stage filter amplification sub-module can be adjusted, so that the filtering range and amplification multiple of the characteristic signal can be controlled according to the actual situation of the characteristic signal, so as to reduce the interference of environmental noise and circuit ripple in the characteristic signal as much as possible and make the amplified characteristic signal easy to be collected by the processor. Among them, the adjustment of the filtering range and amplification range of the third-stage filter amplification sub-module can be realized through a code program.

[0052] The filter amplification module is electrically connected to the processor. The filtered and amplified characteristic signals are transmitted from the filter amplification module to the processor. The memory is electrically connected to the processor, and computer-executable instructions are stored in the memory. The processor performs various arithmetic conversion extraction processes on the characteristic signals transmitted to the processor by executing the computer-executable instructions stored in the memory to obtain the vehicle speed of the target vehicle, that is, to implement the traffic radar speed measurement method.

[0053] Among them, the receiving antenna includes a high-gain antenna and a small-angle antenna. The high-gain antenna has a wide detection distance range and can receive weak signals at a relatively long distance within the radio wave coverage area, so as to effectively receive the echo signals of vehicles in the target lane. The angle of the small-angle antenna is set to 12°-25° and is set horizontally, so that the radio waves emitted through the small-angle antenna can only cover a single lane of the target road, thereby detecting the echo signals of vehicles in a single lane to reduce the interference caused by multiple lanes at a long distance.

[0054] In this embodiment, the processor may include one or more processing cores. The processor uses various interfaces and lines to connect various parts within the traffic speed measurement radar. By running or executing instructions, programs, code sets or instruction sets stored in the memory, and calling the data in the memory, the processor executes various functions of the traffic speed measurement radar and processes data. The processor can be implemented in at least one hardware form of Digital Signal Processing (DSP), Field-Programmable Gate Array (FPGA), or Programmable Logic Array (PLA). The processor can integrate a combination of one or several of a Central Processing Unit (CPU), a Graphics Processing Unit (GPU), and a modem. Among them, the CPU mainly processes the operating system, user interface, application programs, etc.; the GPU is responsible for rendering and drawing the content required to be displayed on the touch display screen; the modem is used to process wireless communication. It can be understood that the above modem may not be integrated into the processor and can be implemented separately through a single chip.

[0055] Among them, the memory may include Random Access Memory (RAM) and may also include Read-Only Memory. Optionally, the memory includes a non-transitory computer-readable storage medium. The memory can be used to store instructions, programs, code, code sets or instruction sets. The memory may include a program storage area and a data storage area. Among them, the program storage area can store instructions for implementing the operating system, instructions for at least one function (such as touch instructions, etc.), instructions for implementing the above-mentioned method embodiments, etc.; the data storage area can store the data involved in the above-mentioned method embodiments. Optionally, the memory may also be at least one storage device located far from the aforementioned processor.

[0056] Such asFigure 2 As shown in the figure, an embodiment of the present invention further provides a traffic radar speed measurement method, including the following steps:

[0057] S1: Obtain the echo signal of the target vehicle, and perform mixing and quadrature processing on the obtained echo signal and the transmitted signal to obtain two characteristic signals of the target vehicle; wherein, the two characteristic signals are the quadrature components of the echo signal of the target vehicle;

[0058] S2: Sample the obtained characteristic signals according to a predetermined number of sampling points, and perform analog-to-digital conversion on the sampled signals to convert the sampled signals from wavelength signals to digital signals;

[0059] S3: Perform anti-interference and arithmetic transformation processing on the obtained digital signals to extract the target signal spectrum of the target vehicle;

[0060] S4: Correct the obtained target signal spectrum through a spectrum correction algorithm to filter out the sine signal in the target signal spectrum;

[0061] S5: Calculate the speed of the target vehicle through the corrected target signal spectrum according to the proportional relationship between speed and frequency in the Doppler dimension.

[0062] It should be noted that in step S1, after the vehicle enters the radar detection area, it will reflect the echo signal to the radar and be received by the radar. The radar performs mixing and quadrature processing on the received echo signal and the transmitted signal to obtain two intermediate-frequency signals of quadrature components. This intermediate-frequency signal is the signal to be processed for the target vehicle and is named the characteristic signal. The phases of the two characteristic signals differ by 90°; the two characteristic signals in the form of quadrature components are convenient for subsequent sampling processing of the signal. The characteristic signal is an intermediate-frequency signal, which is beneficial for the two signal channels to be consistent and improves the stability of subsequent signal sampling.

[0063] In step S2, the characteristic signals after mixing and quadrature processing are transmitted to the processor, and the processor samples the two characteristic signals. When sampling, a sampling rate of 28.19K can be used to collect the signals, and the number of sampling points for each target vehicle is 1024; and analog-to-digital conversion is performed on the sampled characteristic signals to convert the characteristic signals in the form of radio waves into digital signals for subsequent arithmetic processing of the digital signals.

[0064] In step S3, the converted digital signal is successively subjected to DC filtering and windowing to filter out the DC component in the digital signal and eliminate the signal sidelobes in the digital signal, so that the obtained digital signal is free from clutter interference and the authenticity of the signal is improved. Then, the digital signal is subjected to Fourier transform processing to obtain the target signal spectrum in the signal of the target vehicle, that is, to calculate the signal spectrum related to the speed of the target vehicle.

[0065] In step S4, since the echo signal after the mixing orthogonal processing is two intermediate frequency signals with orthogonal components, the obtained target signal spectrum is also a signal spectrum with two orthogonal components. The sine signals in these two signal spectra interfere with the target signal spectrum. Therefore, it is necessary to correct the target signal spectrum through a spectrum correction algorithm to filter out the sine signals in the target signal spectrum, reduce the interference of the sine signals, and improve the accuracy of calculating the speed of the target vehicle.

[0066] In step S5, in the Doppler dimension, the speed is directly proportional to the frequency. The specific calculation formula is as follows:

[0067]

[0068] In the above formula, the angle, the speed of light, and the radar emission frequency are all fixed values. Therefore, the speed of the target vehicle can be calculated based on the corrected target signal spectrum.

[0069] By this method, the received echo signal of the target vehicle is converted into a digital signal for processing, and the target signal spectrum of the target vehicle is extracted from the digital signal. Then, the target signal spectrum is corrected by a spectrum correction method to eliminate the interference of the sine signals in the target signal spectrum, so as to ensure the accuracy of the target vehicle speed calculation. By correcting the target signal spectrum through an algorithm and replacing the use of a filter to filter out the sine signals in the target signal spectrum, it is possible to avoid the signal delay, signal transient response, etc. that may occur in the filter when the data information volume is large, thereby ensuring the radar operation rate and improving the response speed of radar speed measurement.

[0070] In an embodiment of the present invention, before sampling the obtained characteristic signal according to the established number of sampling points, the following steps are further included:

[0071] Perform three-stage filtering and amplification processing on the two characteristic signals. Among them, the first-stage filtering and amplification processing and the second-stage filtering and amplification processing are respectively used to process short-distance data and long-distance data, and the filtering and amplification multiple of the third-stage filtering and amplification processing is suitable for adjustment.

[0072] It should be noted that, because the radar also receives signals reflected from the road surface, guardrails, flowers and plants in the surrounding environment of the road when receiving the callback information of the target vehicle, the echo signal received by the radar contains more clutter. After the echo signal and the transmitted signal are mixed and orthogonal processed, the clutter in the characteristic signal needs to be removed to avoid interference from the clutter and affect the accuracy of subsequent processing. The processing of clutter is carried out through a three-stage filtering and amplifying module. The first stage of filtering and amplifying is used to filter out clutter in the short-range signal and amplify the short-range signal after filtering out the clutter. The second stage of filtering and amplifying is used to filter out clutter in the long-range signal and amplify the long-range signal after filtering out the clutter, so that the short-range signal and the long-range signal are initially free from the interference of clutter and amplified by a certain multiple, and then the short-range signal and the long-range signal are subjected to three-stage filtering and amplifying. The three-stage filtering and amplifying process is to control the filtering frequency band and the amplification multiple through the program code, and to identify and monitor the signal entering the three-stage filtering and amplifying submodule through the program code. According to the strength and frequency of the signal, the filtering frequency and the large range of the three-stage filtering and amplifying process are adjusted to reduce the clutter in the signal after the three-stage filtering and amplifying process as much as possible, and ensure that the gain effect of the signal after the three-stage filtering and amplifying process can meet the needs of subsequent processing.

[0073] In one embodiment of the present invention, obtaining the echo signal of the target vehicle includes:

[0074] S11: transmitting a radio wave signal to the target road, wherein the transmitted radio wave signal can simultaneously cover each lane of the target road within a predetermined range;

[0075] S12: Respectively receive echo signals reflected from vehicles on the target road that enter the coverage range of the radio wave signal, wherein the received echo signals include echo signals reflected from all vehicles within the coverage range of the radio wave signal and echo signals reflected from individual vehicles on each single lane.

[0076] It should be noted that in step S11, a radio wave with a frequency of 24 GHz is emitted by the radio frequency device in the radar and transmitted to the target road through the transmitting antenna. The coverage of the radio wave on the road is controlled by adjusting the installation height and installation angle of the radar. The coverage needs to meet the requirements of covering all lanes of the target road and enabling vehicles on each lane of the target road to enter the coverage range and effectively collect echo signals, so that the radar can detect the speed of multiple vehicles on multiple lanes at the same time, thereby improving the detection efficiency.

[0077] In step S12, when a vehicle on the target road enters the radio wave coverage area, it will return the echo signal to the receiving antenna of the radar. After the receiving antenna receives the reflected echo signal, it is transmitted to the radio frequency device for mixing processing; during the process of receiving the signal, the high-gain antenna receives the signals within the radio wave coverage area of the entire target road. Since the high-gain antenna has the characteristic of a long detection distance, it can detect some tiny signals on the road, thus avoiding inaccurate speed measurement caused by signal loss; the small-angle antenna receives the echo signals of the vehicles in each single lane on the target road, so as to reduce the interference caused by vehicles in other lanes at a long distance, making the received echo signal clearer for subsequent signal processing.

[0078] In an embodiment of the present invention, the processing of de-interfering and performing arithmetic transformation on the obtained digital signal to extract the target signal spectrum of the target vehicle includes:

[0079] S31: Perform DC filtering arithmetic processing on the digital signal to restore the signal deviation that may occur during the signal sampling process;

[0080] S32: Perform arithmetic processing on the digital signal after DC filtering through a Hanning window function to eliminate the interference of high-frequency signals and obtain the frequency, amplitude, and initial phase angle of the sine signal in the digital signal;

[0081] S33: Perform transformation on the digital signal after the Hanning window arithmetic processing through the FFT algorithm to obtain the target signal spectrum in the digital signal.

[0082] It should be noted that in step S31, due to the influence of the bias voltage during the sampling process of the characteristic signal, signal deviation will occur. Therefore, after the sampled signal is converted into a digital signal, DC filtering arithmetic processing is performed to filter out the influence of the bias voltage during the sampling process to restore the true signal and ensure the accuracy of calculating the vehicle speed;

[0083] In step S32, the restored signal is processed through a Hanning window function. The Hanning window function can cancel out the signal side lobes with each other, thereby eliminating the interference of high-frequency signals and signal leakage, further reducing the interference information in the signal and ensuring the integrity of the signal, improving the accuracy of vehicle speed calculation; in addition, through the Hanning window function, the frequency, amplitude, and initial phase angle of the sine signal in the digital signal can also be calculated; the operation process of the Hanning window function is prior art and will not be elaborated here;

[0084] In step S33, the signal processed by the Hanning window operation is transformed by the FFT algorithm, that is, the fast Fourier transform is performed, and the target signal spectrum to be output from the signal processed by the Hanning window function is extracted to facilitate the calculation of the vehicle speed; the fast Fourier transform is a prior art and will not be elaborated here.

[0085] In an embodiment of the present invention, the DC filtering operation processing of the digital signal includes:

[0086] By calculating the average value of the data of the sampling signals with a given number of sampling points, and then subtracting the average value from the value of each sampling signal, the sampled signal is corrected to restore the signal deviation caused during the signal sampling process.

[0087] It should be noted that the DC filtering process of the digital signal is implemented through program code. The specific process is as follows: calculate the average value of the data of 1024 sampling signals of the target vehicle, and then subtract the average value from the data of these 1024 sampling signals respectively to obtain the restored sampling signal, so as to filter out the influence of the bias voltage during signal sampling and restore the true sampling signal.

[0088] In an embodiment of the present invention, the spectrum correction algorithm is the ratio correction method. The correction of the obtained target signal spectrum by the spectrum correction algorithm includes:

[0089] S41: Calculate the sine signal according to the amplitude, frequency and initial phase angle of the sine signal in the target signal spectrum;

[0090] S42: Simulate a simulated sine signal according to the amplitude, frequency and initial phase angle of the sine signal in the target signal spectrum;

[0091] S43: Obtain the target signal after eliminating the sine signal according to the difference between the sine signal and the simulated sine signal.

[0092] It should be noted that in step S41, after being processed by the Hanning window function and transformed by the FFT algorithm, the amplitude, frequency and initial phase angle of the sine signal in the target signal spectrum can be obtained to calculate the sine signal. The specific calculation formula is: x(n)=Acos(2π*f0*t + φ0); where x(n) is the discrete sine signal, A is the amplitude of the sine signal, f0 is the frequency of the sine signal, and φ0 is the initial phase angle of the sine signal;

[0093] In step S42, according to the amplitude, frequency, and initial phase angle of the above sine signal, the amplitude, frequency, and initial phase angle of a simulated sine signal are simulated through the ratio correction method, denoted as A', f0', and φ0'. Then the calculation formula for the simulated sine signal is: y(n)=A'cos(2π*f0'*t + φ0'). Through this formula, the simulated sine signal can be calculated;

[0094] In step S43, the target signal after eliminating the sine signal is calculated based on the sine signal and the simulated sine signal. The calculation formula is: e(n)=x(n) - y(n), where e(n) is the target signal after eliminating the sine signal.

[0095] For a discrete sine signal, amplitude, frequency, and initial phase angle are the three elements of the sine signal. Under the condition of knowing the sampling frequency fs, the three elements of the simulated sine signal can be simulated through the ratio correction method according to the determined three elements of amplitude, frequency, and initial phase angle. Thus, the target signal after eliminating the sine signal, that is, e(n)=x(n) - y(n), can be calculated. As long as the three elements simulated through the ratio correction method are very close to the three elements of the sine signal, then e(n) is the signal after eliminating the sine signal. By using this method to eliminate the interference of the sine signal, the influence of signal delay, signal transient response, etc. caused by using a filter can be avoided.

[0096] In an embodiment of the present invention, after sampling the obtained characteristic signal according to the established number of sampling points, the following steps are further included:

[0097] The important data in the sampled signal is encrypted by using the address offset method.

[0098] It should be noted that important data in the sampled signal, such as filter coefficients and correction coefficients, needs to be encrypted to avoid the loss of important data. The method used for data encryption is the address offset method. Specifically: the important data is edited into a code, then the unique serial number of the processor is obtained, and then the important data and the processor unique serial number are scrambled through a custom formula to form a new code, which is stored in a specific address. Through the above method, when the radar is powered on and runs each time, it is necessary to read the code in the specific address and parse the correct code through a custom formula to enable the radar to run correctly, otherwise it cannot run. Due to adding the processor unique serial number and performing custom formula operations for code parsing in the address offset, the situation of the code running on another processor after being cracked can be effectively avoided, ensuring the security of the data.

[0099] Such as Figure 3As shown in the figure, an embodiment of the present invention further provides a traffic radar speed measurement device, including: an acquisition module 1, a sampling module 2, a processing module 3, a calibration module 4, and a calculation module 5. The acquisition module 1 is used to acquire the echo signal of the target vehicle, and perform mixing and quadrature processing on the acquired echo signal and the transmitted signal to obtain two characteristic signals of the target vehicle; wherein, these two characteristic signals are the quadrature components of the echo signal of the target vehicle, with a phase difference of 90°. The signal after mixing and quadrature processing is an intermediate frequency signal, that is, the characteristic signal is an intermediate frequency signal, which can improve the stability of subsequent signal sampling; the sampling module 2 is used to sample the obtained characteristic signal according to the established number of sampling points, and perform analog-to-digital conversion on the sampled signal to convert the wavelength signal into a digital signal, and the digital signal is convenient for subsequent arithmetic processing; the processing module 3 is used to perform anti-interference and arithmetic transformation processing on the obtained digital signal to extract the target signal spectrum of the target vehicle. Through the processing module 3, the interference of clutter in the digital signal can be filtered out, and the signal spectrum required for calculating the speed of the target vehicle can be extracted; the calibration module 4 is used to calibrate the obtained target signal spectrum through a spectrum calibration algorithm to filter out the sine signal in the target signal spectrum. By eliminating the interference of the sine signal in the target signal spectrum through the calibration module 4, it is possible to avoid signal delay, signal transient response, etc. that occur when using a filter to filter out the sine signal, thereby improving the response speed of radar speed measurement; the calculation module 5 is used to calculate the speed of the target vehicle based on the proportional relationship between speed and frequency in the Doppler dimension through the calibrated target signal spectrum.

[0100] An embodiment of the present invention further provides a computer-readable storage medium, which stores a computer program. When the computer program is read and run by a processor, the traffic radar speed measurement method as described above is implemented.

[0101] Although the present disclosure is disclosed as above, the protection scope of the present disclosure is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present disclosure, and these changes and modifications will all fall within the protection scope of the present invention.

Claims

1. A traffic radar speed measurement method, characterized in that, It includes the following steps: Obtain the echo signal of the target vehicle, and perform mixing and quadrature processing on the obtained echo signal and the transmitted signal to obtain two characteristic signals of the target vehicle; wherein, the two characteristic signals are the quadrature components of the echo signal of the target vehicle. Sample the obtained characteristic signals according to a predetermined number of sampling points, and perform analog-to-digital conversion on the sampled signals to convert the sampled signals from wavelength signals to digital signals. Perform anti-interference and arithmetic transformation processing on the obtained digital signals to extract the target signal spectrum of the target vehicle. Correct the obtained target signal spectrum through a spectrum correction algorithm to filter out the sine signal in the target signal spectrum. According to the proportional relationship between speed and frequency in the Doppler dimension, calculate the speed of the target vehicle through the corrected target signal spectrum.

2. The traffic radar speed measurement method according to claim 1, characterized in that Before sampling the obtained characteristic signals according to a predetermined number of sampling points, the following steps are further included: Perform three-stage filtering and amplification processing on the two characteristic signals, wherein the first-stage filtering and amplification processing and the second-stage filtering and amplification processing are respectively used to process short-distance data and long-distance data, and the filtering and amplification multiple of the third-stage filtering and amplification processing is suitable for being adjusted.

3. The traffic radar speed measurement method according to claim 2, characterized in that, The obtaining of the echo signal of the target vehicle includes: Transmit a radio wave signal to the target road, and the transmitted radio wave signal can cover each lane of the target road within a predetermined range. Receive the echo signals reflected by the vehicles entering the radio wave signal coverage range on the target road respectively, wherein the received echo signals include the echo signals reflected by all the vehicles within the radio wave signal coverage range and the echo signals reflected by the vehicles in each single lane separately.

4. A traffic radar speed measurement method according to claim 2, characterized in that, The performing of anti-interference and arithmetic transformation processing on the obtained digital signals to extract the target signal spectrum of the target vehicle includes: Perform DC filtering arithmetic processing on the digital signals to restore the signal deviation that may occur during the signal sampling process. Perform arithmetic processing on the digital signals after DC filtering through a Hanning window function to eliminate the interference of high-frequency signals and obtain the frequency, amplitude and initial phase angle of the sine signal in the digital signals. Perform transformation on the digital signals after the Hanning window arithmetic processing through the FFT algorithm to obtain the target signal spectrum in the digital signals.

5. A traffic radar speed measurement method according to claim 4, characterized in that, The performing of DC filtering arithmetic processing on the digital signals includes: Calculate the average value of the data of the sampled signals with a predetermined number of sampling points, and then subtract the average value from the value of each sampled signal, so as to correct the sampled signals and restore the signal deviation caused during the signal sampling process.

6. The traffic radar speed measurement method according to claim 4, characterized in that, The spectrum correction algorithm is the ratio correction method, and the correcting of the obtained target signal spectrum through the spectrum correction algorithm includes: Calculate the sine signal according to the amplitude, frequency and initial phase angle of the sine signal in the target signal spectrum. Simulate a simulated sine signal according to the amplitude, frequency and initial phase angle of the sine signal in the target signal spectrum. Obtain the target signal after eliminating the sine signal according to the difference between the sine signal and the simulated sine signal.

7. A traffic radar speed measurement method according to claim 1, characterized in that After sampling the obtained characteristic signal according to a predetermined number of sampling points, the following steps are further included: Encrypt important data in the sampled signal by using an address offset method.

8. A traffic radar speed measuring device, characterized in that, Including: An acquisition module: configured to acquire an echo signal of a target vehicle, and perform mixing and quadrature processing on the acquired echo signal and the transmitted signal to obtain two characteristic signals of the target vehicle; wherein, the two characteristic signals are quadrature components of the echo signal of the target vehicle; A sampling module: configured to sample the obtained characteristic signal according to a predetermined number of sampling points, and perform analog-to-digital conversion on the sampled signal to convert the sampled signal from a wavelength signal to a digital signal; A processing module: configured to perform anti-interference and arithmetic transformation processing on the obtained digital signal to extract the target signal spectrum of the target vehicle; A calibration module: configured to calibrate the obtained target signal spectrum through a spectrum calibration algorithm to filter out sine signals in the target signal spectrum; A calculation module: configured to calculate the speed of the target vehicle based on the proportional relationship between speed and frequency in the Doppler dimension through the calibrated target signal spectrum.

9. A traffic speed measurement radar, characterized in that, Including a radio frequency device, a transmitting antenna, a receiving antenna, a filtering and amplifying module, a processor, and a memory. The radio frequency device is electrically connected to the transmitting antenna and is configured to transmit a signal with a set frequency and cover the transmitted signal within a predetermined range of a target road through the transmitting antenna; the receiving antenna, the radio frequency device, the filtering and amplifying module, and the processor are sequentially electrically connected. The receiving antenna receives the echo signal of a vehicle within the target road, and the radio frequency device and the filtering and amplifying circuit sequentially perform mixing and quadrature processing and filtering and amplifying processing on the echo signal and then transmit it to the processor; The receiving antenna includes a high-gain antenna and a small-angle antenna. The high-gain antenna is configured to receive the echo signal of a vehicle within the entire target road, and the small-angle antenna is configured to receive the echo signal of a vehicle within each single lane of the target road; The memory stores computer-executable instructions, and when the computer-executable instructions are executed by the processor, the traffic radar speed measurement method according to any one of claims 1-7 is implemented.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program, and when the computer program is read and run by the processor, the traffic radar speed measurement method according to any one of claims 1-7 is implemented.

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