CN113096260B

CN113096260B - Detection method and device of ETC system, storage medium and terminal

Info

Publication number: CN113096260B
Application number: CN202110642780.XA
Authority: CN
Inventors: 卿建章; 王冬; 刘阳; 周焕钦; 钱敬之; 叶世昕
Original assignee: Sichuan Jingwei Traffic Engineering Technology Co ltd
Current assignee: Sichuan Jingwei Traffic Engineering Technology Co ltd
Priority date: 2021-06-09
Filing date: 2021-06-09
Publication date: 2021-08-27
Anticipated expiration: 2041-06-09
Also published as: CN113096260A

Abstract

The invention relates to a detection method, a device, a storage medium and a terminal of an ETC system, comprising the following steps: s11, performing data caching on the data obtained in the data receiving step through a double-circulation buffer area, filtering out data packets, copying the data packets, and then drawing and storing the data packets; s12, selecting a file for storing data, obtaining data frames of transaction in a power value comparison mode, processing the power value of each frame of transaction data in a sliding average mode, and drawing a power curve; and S13, acquiring the actual occupied broadband of the ETC signal for the data frame of the transaction according to the ASK signal characteristics, encoding and displaying the lead code according to an FM0 encoding mode, and calculating the transaction distance of the ETC portal according to a distance wheel encoder. According to the invention, the lead code and the wake-up code of the ETC signal are found by researching the ETC communication protocol, all signals which do not meet the conditions can be filtered, and the ETC signal can be rapidly obtained for detection.

Description

Detection method and device of ETC system, storage medium and terminal

Technical Field

The present invention relates to the field of communications technologies, and in particular, to a detection method and apparatus for an ETC system, a storage medium, and a terminal.

Background

Electronic Toll Collection (ETC) is a special short-range communication carried out between a vehicle-mounted Electronic tag installed on a vehicle windshield and a microwave antenna on an ETC lane of a Toll station, and a computer networking technology and a bank are used for carrying out background settlement processing, so that the purpose that a vehicle can pay the Toll of an expressway or a bridge without stopping the vehicle through the expressway or the bridge Toll station is achieved, and the passing efficiency is improved.

As the ETC technology increasingly and widely covers the highway toll collection system in China, the reliability of the system is more and more important, and the events of indiscriminate toll collection, no lever raising and the like occur at all times, so that the problem that how to detect the effectiveness of the ETC system needs to be solved at the present stage is solved.

Disclosure of Invention

The invention aims to overcome the defects of the prior art, provides a detection method, a detection device, a storage medium and a terminal of an ETC system, and overcomes the defects of the prior ETC system.

The purpose of the invention is realized by the following technical scheme: a detection method of an ETC system, the detection method comprising a data reception step and a data processing step, the data processing step comprising:

s11, performing data caching on the data obtained in the data receiving step through a double-circulation buffer area, filtering out data packets, copying the data packets, and then drawing and storing the data packets;

s12, selecting a file for storing data, obtaining data frames of transaction in a power value comparison mode, processing the power value of each frame of transaction data in a sliding average mode, and drawing a power curve;

and S13, acquiring the actual occupied broadband of the ETC signal for the data frame of the transaction according to the ASK signal characteristic, encoding and displaying the lead code according to an FM0 encoding mode, and calculating the transaction distance of the ETC portal according to a distance wheel encoder.

The selecting a file storing data obtains a data frame of transaction through a power value comparison mode, and the processing of the power value of each frame of transaction data in a moving average mode specifically includes:

selecting a file for storing data and traversing the file to obtain frame data M with the maximum power as the reference data for judging the position of the portal;

reading a file from the beginning, comparing the power value recorded in the currently read data frame with a threshold awakening threshold value, awakening the OBU equipment when the data frame which is greater than or equal to the threshold awakening threshold value appears for the first time, and recording the currently read data frame as an initial data frame A of an effective signal;

when the OBU equipment and the portal RSU equipment carry out transaction, a transaction power threshold value is obtained, all data frames between an initial data frame A and a maximum data frame M, which are larger than or equal to the transaction power threshold value, are used as data frames capable of carrying out transaction, and the data frames capable of carrying out transaction are recorded;

reading the tradable data frame, recording the power value of the currently read tradable data frame as P, calculating the data sum of N values before the power value P, dividing the data sum by the total number N to obtain a new power value Pn of the currently read tradable data frame, covering the new power value Pn with the new power value Pn, and repeating the step to obtain the new power values Pn of all the tradable data frames.

The data frame to the transaction obtains the actual broadband that occupies of ETC signal according to ASK signal characteristic, shows the lead code according to FM0 encoding mode, calculates ETC portal transaction distance according to the distance wheel encoder and specifically includes:

obtaining a maximum positive and negative frequency deviation value from the recorded tradable data frame, and obtaining an actual occupied broadband of the ETC signal according to the sum of the theoretical bandwidth 512k of the ASK signal and the absolute value of the positive and negative frequency deviation value;

encoding 16 1 s and 16 0 s of the lead code according to an FM0 encoding mode and displaying the lead code graphically; the implementation mode is as follows: the FM0 code is characterized in that 1 represents no flip and 0 represents flip in one period. The waveform width of the first half "1" of the pattern is twice the waveform width of the second half "0".

And calculating the pulse number difference D of the distance wheel encoder between the data frame M where the maximum power is located and the initial data frame A, and calculating the transaction distance Q = D/J multiplied by K of the current ETC portal according to the pulse number J generated by one circle of the distance wheel encoder calibrated at the beginning of equipment installation and the perimeter K of the wheel.

The data caching the data obtained from the data receiving step through a double-circulation buffer specifically comprises:

opening X memory space blocks with the size of Y in a buffer area, wherein the space blocks comprise free space blocks and space blocks filled with data, setting a queue for each space block to manage, and placing all the free space blocks in the free space block queue during initialization;

when filling data, applying for a free space block from the buffer, returning to a head address pointer P1 of the free space block, copying the data to be stored from the address starting from the pointer P1, if the size of the data to be stored is larger than Y, the maximum copy size of the data is Y, otherwise copying according to the actual size of the data, putting the pointer P1 into a space block queue containing the data after the data copy is completed, and writing the actual size of the current copied data;

when the data is taken out, a space block containing the data is applied from the buffer, a head address pointer P2 of the space block containing the data is returned, the data is copied to an external memory needing to use the data from P2, the copying size of the data is the size of the data during storage, and the pointer P2 is placed in a free space block queue after the copying is finished.

The data receiving step includes:

performing band-pass filtering on the received signal, and then mixing the signal with a local oscillator signal with the frequency of 5833 MHz;

transmitting the mixed signals to an ADC (analog to digital converter), wherein the ADC samples the signals at a sampling rate of 50MHz, and converts analog signals into digital signals;

carrying out DDC processing in a sampling dual-channel mode on the data signal, and detecting 5840MHz and 5830MHz signals transmitted by the ETC portal frame;

dividing the acquired signals into two paths, respectively carrying out envelope detection, carrying out FFT processing on the 14KHz square wave signals marked in the detected ETC signal protocol head, calculating signal power, signal frequency offset and detection threshold, and carrying out envelope sampling judgment on the 256KHz signals;

and decoding the lead code, the starting mark and the MAC address of the judged 256KHz signal, and uploading the measured ETC power, frequency deviation, channel, GPS and range wheel encoder pulse signals if the decoded lead code, starting mark and MAC address are correct.

The detection method also comprises the steps of simultaneously selecting a plurality of files for storing data in a multi-thread running mode, and respectively executing the step S12 and the step S13 on each file to obtain an independent result of each file.

The detection device of the ETC system comprises a receiving end and a data processing terminal which establishes communication connection with the receiving end; the data processing terminal includes:

double-loop buffer area: the data buffer is used for caching the data obtained from the receiving end through a double-circulation buffer area, and the filling and the taking out of the data are realized through the movement of a space block head address pointer;

a data analysis module: selecting a file for storing data from the double-circulation buffer area, obtaining data frames of transaction in a power value comparison mode, and processing the power value of each frame of transaction data in a moving average mode; acquiring the actual occupied broadband of the ETC signal for the data frame of the transaction according to the ASK signal characteristics, coding and displaying the lead code according to the FM0 coding mode, and calculating the transaction distance of the ETC portal frame according to the distance wheel coder;

a real-time drawing module: and the power curve is drawn according to the power value of the transaction data frame processed and obtained by the data analysis module.

The receiving end comprises a radio frequency module and an intermediate frequency module; the radio frequency module realizes the collection and the mixing of signal, and the intermediate frequency module is used for with analog signal after the radio frequency module is handled changes digital signal into and filters it, transmits after obtaining the ETC signal for data processing terminal.

The double-loop buffer area includes:

a space block setting unit: opening X memory space blocks with the size of Y in a buffer area, wherein the space blocks comprise free space blocks and space blocks filled with data, setting a queue for each space block to manage, and placing all the free space blocks in the free space block queue during initialization;

a data filling unit: applying for a free space block from the buffer area, returning a head address pointer P1 of the free space block, copying data to be stored from the address starting from the P1 pointer, if the size of the data to be stored is larger than Y, the maximum copy size of the data is Y, otherwise copying according to the actual size of the data, putting the P1 pointer into a space block queue filled with the data after the data is copied, and simultaneously writing the actual size of the current copied data;

a data extraction unit: applying for a space block containing data from the buffer area, returning a head address pointer P2 of the space block containing data, copying the data to an external memory needing to use the data from P2, wherein the copying size of the data is the size of the data during storage, and after the copying is finished, putting the P2 pointer into a free space block queue.

Wherein, the data frame to the transaction obtains the actual broadband that occupies of ETC signal according to the ASK signal characteristic, demonstrates the lead code according to FM0 encoding mode, calculates ETC portal transaction distance according to the distance wheel encoder and specifically includes:

acquiring a maximum positive and negative frequency deviation value from the recorded tradable data frame, and acquiring an actual occupied broadband of the ETC signal according to the sum of the ASK theoretical bandwidth 512K and the absolute value of the positive and negative frequency deviation value;

encoding 16 1 s and 16 0 s of the lead code according to an FM0 encoding mode and displaying the lead code graphically;

and calculating the pulse number difference D of the distance wheel encoder between the data frame M where the maximum power is located and the initial data frame A, generating the pulse number J according to one circle of the distance wheel encoder calibrated when the equipment is installed at the utmost, and calculating the transaction distance Q = D/JXK of the current ETC portal by combining the perimeter K of the wheels.

A storage medium for ETC system detection comprising computer readable computer program instructions stored thereon which when executed perform the contents of the data processing steps.

An intelligent terminal for ETC system detection comprises a memory and a processor, wherein computer program instructions are stored in the memory, and the processor is used for reading the computer program instructions stored in the memory and executing the content of the data processing step when in operation.

The invention has the following advantages: the utility model provides a detection method, device, storage medium and terminal of ETC system, with the function integration of multiple instrument in a equipment, it is lighter and handy, can fix in roof luggage rack, through the dustproof waterproof and anti-vibration of optimal design, the cooperation is apart from the wheel and can not influenced by the speed of a motor vehicle, detect safelyr, and efficiency is higher, through studying ETC communication protocol, finds ETC signal's lead code and awaken the sign indicating number, can filter all signals that are not conform to the condition, can obtain ETC signal fast and detect.

Drawings

FIG. 1 is a schematic diagram of the apparatus of the present invention;

FIG. 2 is a schematic diagram of a work flow of a receiving end;

FIG. 3 is a schematic diagram of a data fill-in process of a dual-cycle buffer area;

FIG. 4 is a schematic diagram of a data fetch workflow for a dual cycle cache region;

FIG. 5 is a schematic flow chart of the method of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all the embodiments. The components of the embodiments of the present application, generally described and illustrated in the figures herein, can be arranged and designed in a wide variety of different configurations. Thus, the detailed description of the embodiments of the present application provided below in connection with the appended drawings is not intended to limit the scope of the claimed application, but is merely representative of selected embodiments of the application. All other embodiments, which can be derived by a person skilled in the art from the embodiments of the present application without making any creative effort, shall fall within the protection scope of the present application. The invention is further described below with reference to the accompanying drawings.

As shown in fig. 1, the present invention is composed of a receiving end and a data processing terminal, and adopts a hundred mega network to realize the two-way communication between the receiving end and the data processing terminal; the receiving end comprises a radio frequency module and an intermediate frequency module, the radio frequency module is responsible for collecting and mixing signals, the intermediate frequency module is responsible for converting analog signals transmitted by the radio frequency module into digital signals, the signals are filtered according to requirements, and finally the ETC signals are obtained and then transmitted to the data processing terminal.

The data processing terminal adopts a double-circulation buffer area to perform data caching after receiving data, then filters out data packets, copies the data packets and then respectively uses the data packets for drawing and storing, and the stored files can be analyzed online and offline so as to obtain measurement parameters of the detected ETC portal.

As shown in fig. 2, the rf module in the figure includes a BPF (band pass filter), a mixer, and an ADC (analog-to-digital converter), and the rest is an intermediate frequency module, and mainly uses an FPGA chip to perform digital signal processing, and the specific processing steps are as follows:

a1, processing the received signal by a band-pass filter, and then mixing the signal with a local oscillator signal with the frequency of 5833 MHz;

a2, transferring the signals to an ADC after frequency mixing, wherein the ADC samples the signals at a sampling rate of 50MHz, and converts the analog signals into digital signals;

a3, DDC (digital down conversion) processing is performed on the digital signal. The DDC adopts a dual-channel mode, and simultaneously detects 5840MHz and 5830MHz signals transmitted by the ETC portal frame;

a4, dividing the collected signals into two paths, respectively carrying out envelope detection on the two paths of signals, detecting a 14KHz square wave signal marked in an ETC signal protocol header, and carrying out FFT (fast Fourier transform) processing if the 14KHz square wave signal is detected;

a5, FFT processing is used for calculating information such as signal power, signal frequency offset, a detection threshold and the like, the detection threshold is set to be more than or equal to-70 dB (signals required by ETC transaction are normally more than-65 dB, so that-70 dB can be set to filter out a lot of invalid signals), and the detection threshold is used for sampling judgment of 256KHz signal envelopes;

a6, decoding is used for decoding a lead code, a start mark, an MAC address and the like of the judged 256KHz signal;

a7, if the lead code, the start mark and the MAC address are correct, the communication module is triggered to upload the measured ETC power, frequency deviation, channel, GPS, pulse signal of the distance wheel encoder and other information through a hundred mega network interface.

In the whole detection process, the required time is about 4ms, and the actual ETC portal signal transmission interval is about 6 ms. Therefore, the time used for a complete detection process is less than the transmission interval time, and the device can receive all complete ETC signals.

Furthermore, the whole process of the data processing terminal is to acquire data from a receiving end, then cache the data by using a double-circulation buffer area, acquire the data from the buffer area by a sub-thread for processing, copy one copy of the data, and respectively perform drawing and storage to a file. And reading data from the file for analysis to obtain the ETC portal frame measurement parameter value.

As shown in fig. 3 and 4, the principle of the dual-cycle buffer is to open X Y-sized memory space blocks, the space blocks are separated into free space blocks and space blocks containing data, each space block is managed by a queue, and all the free space blocks are placed in the free queue during initialization.

When filling data, applying for a free block from the buffer, if there is a free space block, the application is successful, and returning to the head address pointer p1 of the free space block. The data to be stored is copied from the address starting from the p1 pointer, the copy size being maximum to the original space Y. If the data is smaller than the initial space, the actual copy size is data size N. After the data copy is completed, the p1 pointer is put into the queue of space blocks containing data, and the actual size of the currently copied data is written.

And when the data is taken out, applying for a space block containing the data from the buffer, and if the application is successful, returning the initial address p2 of the space block containing the data. And copying data to an external memory needing to use the data from p2, wherein the copy size is the data size N stored before. After copying is complete, the p2 pointer is placed in the empty space block queue for use in subsequent cycles.

The design of the whole double-circulation buffer area only carries out deep copy when data are copied in and data are copied out. The conversion operation from the empty space block queue to the space block queue filled with data and from the space block queue filled with data to the empty space block queue is only to move the pointer of the first address, so that multiple copying is avoided, and the time and the expense are reduced.

Further, as shown in fig. 5, the data processing step includes the following steps:

and selecting a file for storing data, traversing the file once, and finding out the frame data M with the maximum power as the reference data for judging the position of the portal frame. And then reading the file from the beginning, and comparing the power value recorded in the current read data frame with a threshold value of an awakening threshold, wherein the threshold value of the awakening threshold of the OBU (on board unit) is set to-45 dB. When a data frame which is larger than or equal to-45 dB appears for the first time, recording the current data frame as a valid signal starting frame A, and awakening the OBU equipment at the moment. After the OBU equipment is awakened, transaction can be carried out with the portal RSU (road side unit) equipment, and the power required by the transaction is greater than or equal to-65 dB. Therefore, all data from the data frame a to the maximum frame M, as long as it is equal to or greater than-65 dB, is regarded as tradable power data, and the tradable data is recorded for use as subsequent drawing data and analysis data.

Since the radio transmission is greatly influenced by various factors in the air, when the data is collected for data analysis, the power value can be calculated in a moving average mode to reduce the influence caused by some abnormal data.

Reading the tradable data, recording the power value of the currently read tradable data frame as P, and taking the data sum of N values of the current value forward, dividing the data sum by the total number to obtain a new power value Pn covering the current value P. That is, Pn = (P + P _ N-1+ P _ N-2+ P _ N-3+ …)/N. The power value of each frame data is obtained in this manner, that is, the value of the power curve is plotted.

And finally, when a conclusion is generated, obtaining the maximum positive and negative frequency deviation value from the recorded data frame, and obtaining the actual occupied bandwidth of the ETC signal according to the sum of the theoretical bandwidth 512k of the ASK signal and the absolute value of the positive and negative frequency deviation value. The 16 1 s and 16 0 s of the preamble are graphically displayed in the FM0 encoding mode. And the number difference D of the encoder pulses is calculated from the distance between the data frame M where the maximum power exists and the initial frame A. The wheel encoder generates J pulses in one revolution, combined with a wheel circumference of K, calibrated at the time of initial installation of the device. And calculating to obtain the transaction distance Q = D/J xK of the current ETC portal. And finally, information such as the transaction distance, the working frequency, the working signal intensity, the occupied bandwidth, the lead code and the like of the ETC portal frame can be given by combining the frequency information recorded in the data frame, so that highway maintenance personnel can be helped to quickly know the working state of the ETC system.

The method can also support the simultaneous analysis of a plurality of files, and can respectively execute the steps on each file in a backstage sub-thread in a circulating mode to obtain the independent result and conclusion of each file.

Another embodiment of the invention is directed to a storage medium for ETC system detection, comprising computer-readable computer program instructions stored thereon which, when executed, perform the contents of the data processing steps.

Yet another embodiment of the present invention relates to an intelligent terminal for ETC system detection, which includes a memory having computer program instructions stored therein and a processor for reading the computer program instructions stored in the memory and executing the contents of the data processing steps when running.

The foregoing is illustrative of the preferred embodiments of this invention, and it is to be understood that the invention is not limited to the precise form disclosed herein and that various other combinations, modifications, and environments may be resorted to, falling within the scope of the concept as disclosed herein, either as described above or as apparent to those skilled in the relevant art. And that modifications and variations may be effected by those skilled in the art without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. A detection method of an ETC system is characterized in that: the detection method comprises a data receiving step and a data processing step, wherein the data processing step comprises the following steps:

s13, acquiring the actual occupied broadband of the ETC signal for the data frame of the transaction according to the ASK signal characteristics, encoding and displaying the lead code according to an FM0 encoding mode, and calculating the transaction distance of the ETC portal according to a distance wheel encoder;

selecting a file for storing data, obtaining data frames of transaction in a power value comparison mode, and processing the power value of each frame of transaction data in a moving average mode specifically comprises the following steps:

reading the tradable data frame, recording the power value of the currently read tradable data frame as P, calculating the data sum of N values before the power value P, dividing the data sum by the total number N to obtain a new power value Pn of the currently read tradable data frame, covering the new power value Pn with the new power value Pn, and repeating the step to obtain new power values Pn of all the tradable data frames;

acquiring a maximum positive and negative frequency deviation value from the recorded tradable data frame, and acquiring an actual occupied broadband of the ETC signal according to the sum of the theoretical bandwidth 512k of the ASK signal and the absolute value of the positive and negative frequency deviation value;

and calculating the pulse number difference D of the distance wheel encoder between the data frame M where the maximum power is located and the initial data frame A, generating the pulse number J according to one circle of the distance wheel encoder calibrated at the beginning of equipment installation, and calculating the transaction distance Q = D/J multiplied by K of the current ETC portal by combining the perimeter K of the wheels.

2. The detection method of the ETC system according to claim 1, wherein: the data caching the data obtained from the data receiving step through a double-circulation buffer specifically comprises:

3. The detection method of the ETC system according to claim 1, wherein: the data receiving step includes:

and decoding the lead code, the starting mark and the MAC address of the judged 256KHz signal, and uploading the measured ETC power, frequency deviation, channel, GPS and distance wheel encoder pulse signals if the decoded lead code, starting mark and MAC address are correct.

4. The detection method of the ETC system according to claim 1, wherein: the detection method also comprises the steps of simultaneously selecting a plurality of files for storing data in a multi-thread running mode, and respectively executing the step S12 and the step S13 on each file to obtain an independent result of each file.

5. The utility model provides a detection device of ETC system which characterized in that: the system comprises a receiving end and a data processing terminal which establishes communication connection with the receiving end; the receiving end comprises a radio frequency module and an intermediate frequency module; the radio frequency module is used for acquiring and mixing signals, and the intermediate frequency module is used for converting analog signals processed by the radio frequency module into digital signals and filtering the digital signals to obtain ETC signals and then transmitting the ETC signals to the data processing terminal;

the data processing terminal includes:

a data analysis module: the double-circulation buffer area is used for selecting a file for storing data from the double-circulation buffer area, obtaining data frames of transaction in a power value comparison mode, and processing the power value of each frame of transaction data in a moving average mode; acquiring the actual occupied broadband of the ETC signal according to the ASK signal characteristics of the data frame of the transaction, coding and displaying the lead code according to the FM0 coding mode, and calculating the transaction distance of the ETC portal according to the distance wheel coder;

a real-time drawing module: the power curve is drawn according to the power value of the transaction data frame processed by the data analysis module;

the data frame to the transaction obtains the actual broadband that occupies of ETC signal according to ASK signal characteristic, shows the lead code according to FM0 encoding mode, specifically includes according to the ETC portal transaction distance of distance wheel encoder calculation:

6. The detection device of an ETC system according to claim 5, wherein: the double-loop buffer area includes:

a space block setting unit: the method comprises the steps that X memory space blocks with the size of Y and including free space blocks and space blocks filled with data are opened up in a buffer area, each space block is provided with a queue for management, and all the free space blocks are placed in the free space block queues during initialization;

a data filling unit: the method comprises the steps that a free space block is applied from a buffer area, a head address pointer P1 of the free space block is returned, data to be stored are copied from an address starting from the P1 pointer, if the size of the data to be stored is larger than Y, the maximum copy size of the data is Y, otherwise, the data are copied according to the actual size of the data, the P1 pointer is placed into a space block queue filled with the data after the data are copied, and the actual size of the current copied data is written at the same time;

a data extraction unit: the method is used for applying for a space block containing data from a buffer, returning a head address pointer P2 of the space block containing data, copying the data to an external memory needing to use the data from P2, wherein the copying size of the data is the size of the data during storage, and after the copying is finished, the P2 pointer is placed in a free space block queue.

7. A storage medium for ETC system detection, characterized by: comprising stored computer-readable computer program instructions which, when executed, perform the data processing steps of any of claims 1 to 4.

8. The utility model provides an intelligent terminal for ETC system detects which characterized in that: comprising a memory having stored therein computer program instructions and a processor for reading the computer program instructions stored in the memory and executing the contents of the data processing steps of any of claims 1 to 4 when run.