CN113253237B - Railway contact net measuring method and system based on radar system - Google Patents

Abstract

The present application relates to a railway catenary measurement method and a catenary measurement system based on a radar system. The method is applied to a catenary measurement system including a master radar, a slave radar and a master control device that communicate with each other. The master control device controls the two The two radars work synchronously, collect radar echoes of the same target at the same time and different viewing angles, and perform pulse compression, and then identify the peak position of the catenary in the pulse compressed image, and then use the time differential interference technology to interfer with the peak complex scattering data. After processing, the displacement of the catenary relative to the two radars is obtained respectively, and then the lead-through deformation and the pull-out value deformation of the catenary are obtained by solving the binary equation. This method has the advantages of remote non-contact, high measurement accuracy, high efficiency and real-time performance, and convenient operation and deployment.

Description

Railway catenary measurement method and catenary measurement system based on radar system

technical field

The present application relates to the technical field of radar detection, and in particular, to a railway catenary measurement method and a catenary measurement system based on a radar system.

Background technique

The pantograph system composed of the railway catenary and the pantograph on the top of the locomotive is one of the key equipment in the railway system. The catenary is a transmission line erected in a "zigzag" shape along the top of the rail to provide the locomotive with the energy required for high-speed running. . The quality of the catenary directly affects the current receiving performance of the pantograph and the safety of train operation. Because the catenary is arranged in the open air along the railway, the working environment is harsh, the traction (load) current changes greatly during operation, and the vehicle body vibrates violently, which makes the geometry of the catenary. Parameters and electrical parameters are in complex dynamic changes all the time. The catenary is designed and constructed in accordance with certain railway technical standards, and its main key technical indicators include: geometric parameters such as contact wire guide height and pull-out value, and mechanical parameters such as catenary tension and dynamic amplitude. Appropriate geometric parameters and mechanical parameters can ensure that the contact position and pressure of the pantograph and catenary meet the relevant technical specifications. Otherwise, if the contact pressure of the pantograph and catenary is too small, the off-line rate will increase, and sparks or arcs will be generated. The electric ablation of the pantograph will reduce the service life of the pantograph, and the arcing will cause serious damage to the traction motor and affect the traction safety of the locomotive; Produces greater mechanical wear and reduces its service life. Once the pantograph and catenary system fails, power outage will cause traffic interruption and may cause safety accidents. Therefore, how to accurately, quickly and automatically detect catenary parameters is a major requirement for railway construction and operation and maintenance departments.

The higher the running speed of the train, the higher the requirements for the pantograph system, and the higher and higher requirements for the catenary measurement of high-speed railways, especially the next-generation high-speed railways. At present, catenary measurement can be divided into two technical approaches: contact and non-contact measurement; contact sensors include pressure sensors, angular displacement sensors and acceleration sensors, etc. These methods will accelerate the wear of pantograph and catenary system and reduce its service life. Non-contact sensors include infrared thermal imaging detection, optical image detection and laser scanning detection. Due to the small cross-sectional area of the catenary and the high-speed movement of the locomotive, these sensors also have great limitations. Among them, infrared thermal imaging detectors cannot precisely measure geometric deformation, optical image detection has a limited range, and laser scanners are very sensitive to pointing errors caused by vehicle motion. In addition, these non-contact measurement methods are affected by harsh weather conditions such as sunlight, rain, snow, dust and fog. impact, poor environmental adaptability.

SUMMARY OF THE INVENTION

Based on this, it is necessary to provide a railway catenary measurement method and a catenary measurement system based on a radar system that can adapt to various environments and have high measurement accuracy, aiming at the above technical problems.

A railway catenary measurement method based on a radar system, the method is applied to a catenary measurement system, the catenary measurement system comprises a master radar, a slave radar and a master control device that communicate with each other, the master radar and the slave radar are respectively Distributed on both sides of the railway, and the connection between the two is perpendicular to the center line of the railway;

The railway catenary measurement method includes:

The master control device sends work instructions to the master radar and the slave radar according to a preset synchronization scheme;

The master radar and the slave radar transmit measurement signals to the same measurement point of the catenary according to the work instruction, and send the received radar echo signals to the master control device;

The main control device performs pulse compression according to the main radar and the radar echo signal at the initial observation time sent from the radar to obtain corresponding pulse compression images, and respectively identifies the peak positions of the catenary in each of the pulse compression images, and acquiring the wave crest complex scattering data corresponding to the wave crest position;

The actual coordinates of the main radar and the slave radar are extracted from the preset local coordinate system, and the calculation is performed according to the actual coordinates and the corresponding wave peak complex scattering data to obtain the contact net at the initial observation time. the initial distance between the radars and the initial coordinates of the catenary;

Two sets of complex scattering observation vectors corresponding to the master radar and the slave radar are obtained according to the radar echo data at multiple observation times, and the time difference interference method is used to obtain the complex scattering observation vectors at each observation time according to the two sets of complex scattering observation vectors. The displacement of the catenary relative to the master radar and the slave radar, respectively;

According to the actual coordinates of the main radar and the subordinate radar, the initial coordinates of the catenary, the initial distance between the catenary and the main radar and the subordinate radar respectively, and the relative relationship between the catenary and the main radar and the subordinate radar at each observation moment. From the displacement between the radars, based on the formula for finding the distance between two points, construct the equations in which the change of the guide height and the change of the pull-out value of the catenary are unknowns, and solve the equation to obtain the change of the guide height and the change of the pull-out value. ;

The mechanical parameters of the catenary are obtained by spectrum analysis according to the variation of the lead height and the variation of the pull-out value.

In one of the embodiments, the preset synchronization scheme includes a first synchronization scheme and a second synchronization scheme;

The first synchronization scheme includes controlling the master radar and the slave radar to transmit measurement signals with waveforms of different frequencies or codes at the same time;

The second synchronization scheme includes controlling the master radar and the slave radar to alternately transmit measurement signals of the same frequency and the same encoding.

In one of the embodiments, the bandwidth of the measurement signals transmitted by the master radar and the slave radar is greater than 500 MHz.

In one of the embodiments, after the master control device sends a work instruction to the master radar and the slave radar according to a preset synchronization scheme, it includes:

The master radar and the slave radar transmit measurement signals to the same measurement point of the catenary according to the work instruction, and after receiving the radar echo signals, pulse compression is performed on the radar echo signals respectively to obtain compressed radar echoes. signal and send it to the master device;

The main control device converts the compressed radar echo signal at the initial observation time sent by the main radar and the slave radar into a pulse-compressed image, and identifies the peaks of the catenary in each of the pulse-compressed images. position, and obtain the wave peak complex scattering data corresponding to the wave peak position.

In one embodiment, the actual coordinates of the master radar and the slave radar are extracted from a preset local coordinate system, and the calculation is performed according to each of the actual coordinates and the corresponding wave peak complex scattering data to obtain the data at the initial observation time. The initial distance between the catenary and the main radar and the secondary radar respectively, and the initial coordinates of the catenary, wherein after obtaining the initial distance between the catenary and the main radar and the secondary radar at the initial observation time include:

According to the actual coordinates of the main radar and the initial distance between the main radar and the catenary, construct the first equation in which the initial coordinates of the catenary are unknowns;

According to the actual coordinates of the radar and the initial distance between the radar and the catenary, a second equation with the initial coordinates of the catenary as an unknown number is constructed;

Solve the first equation and the second equation to obtain the initial coordinates of the catenary.

In one embodiment, the method is based on the actual coordinates of the main radar and the subordinate radar, the initial coordinates of the catenary, the initial distances between the catenary and the main radar and the subordinate radar respectively, and the data obtained at each observation moment. The above-mentioned catenary is respectively relative to the displacement between the main radar and the slave radar. Based on the formula for calculating the distance between two points, an equation in which the change of the guide height and the change of the pull-out value of the catenary are unknown is constructed, and the derivative is obtained by solving it. High deltas and pull-out deltas include:

Let the initial observation time be the previous observation time;

According to the actual coordinates of the main radar, the initial coordinates of the catenary, the variation of the guide height, the variation of the pull-out value, the initial distance between the main radar and the catenary, and the displacement of the catenary relative to the main radar at the current observation time , construct the first distance equation between the main radar and the catenary at the current observation moment;

According to the actual coordinates of the slave radar, the initial coordinates of the catenary, the change of the lead height, the change of the pull-out value, the initial distance between the slave radar and the catenary, and the displacement of the catenary relative to the slave radar at the current observation time , construct the second distance equation between the radar and the catenary at the current observation moment;

The first distance equation and the second distance equation are solved at a plurality of observation times, respectively, to obtain the variation of the lead height and the variation of the pull-out value corresponding to each observation time.

In one of the embodiments, the obtaining of the mechanical parameters of the catenary by performing spectrum analysis according to the variation of the lead height and the variation of the pull-out value includes:

The maximum lead height change and the maximum pull value change are respectively found in the lead height change amount and the pull value change amount corresponding to each observation time, and according to the maximum lead height change amount and the maximum pull value change amount respectively Carry out the calculation to obtain the lead-up shock amplitude and the pull-out shock amplitude accordingly;

Fourier transform is performed according to the lead height variation corresponding to each observation time to obtain the lead height change spectrum, and the fundamental frequency component is extracted from the lead height change spectrum. According to the fundamental frequency component and the tension formula of the catenary cable The tensile force of the catenary cable, the linear density of the chord cable and the equivalent length of the catenary cable are estimated to obtain the estimated tensile force, linear density and equivalent length.

In one embodiment, the method for measuring the railway catenary further includes: after performing spectrum analysis according to the change in the lead height and the change in the pull-out value to obtain the mechanical parameters of the catenary:

The catenary is judged according to the mechanical parameters:

If the mechanical parameters meet the preset design range, it is judged that the catenary of the part corresponding to the observation time is working normally;

If the mechanical parameters do not meet the preset design range, it is determined that the part of the catenary has a potential failure.

The application also provides a catenary measurement system, the catenary measurement system includes a master radar, a slave radar and a master control device that communicate with each other, the master radar and the slave radar are respectively distributed on both sides of the railway, and the other The connection between the lines is perpendicular to the railway centerline;

The master control device sends work instructions to the master radar and the slave radar according to a preset synchronization scheme;

The master radar and the slave radar transmit measurement signals to the same measurement point of the catenary according to the work instruction, and send the received radar echo signals to the master control device;

The main control device performs pulse compression according to the main radar and the radar echo signal at the initial observation time sent from the radar respectively to obtain corresponding pulse compression images, and respectively identifies the peak positions of the catenary in each of the pulse compression images and acquiring the wave peak complex scattering data corresponding to the wave peak position;

The actual coordinates of the main radar and the slave radar are extracted from the preset local coordinate system, and the calculation is performed according to the actual coordinates and the corresponding wave peak complex scattering data to obtain the contact net at the initial observation time. the initial distance between the radars, and the initial coordinates of the catenary;

Two sets of complex scattering observation vectors corresponding to the master radar and the slave radar are obtained according to the radar echo data at multiple observation times, and the time difference interference method is used to obtain the complex scattering observation vectors at each observation time according to the two sets of complex scattering observation vectors. The displacement of the catenary relative to the master radar and the slave radar, respectively;

According to the actual coordinates of the main radar and the subordinate radar, the initial coordinates of the catenary, the initial distance between the catenary and the main radar and the subordinate radar respectively, and the relative relationship between the catenary and the main radar and the subordinate radar at each observation moment. From the displacement between the radars, based on the formula for finding the distance between two points, construct the equations in which the change of the guide height and the change of the pull-out value of the catenary are unknowns, and solve the equation to obtain the change of the guide height and the change of the pull-out value. ;

The mechanical parameters of the catenary are obtained by spectrum analysis according to the variation of the lead height and the variation of the pull-out value.

In one embodiment, the main control device further includes: after obtaining the mechanical parameters of the catenary by performing spectrum analysis according to the lead height variation and the pull-out value variation:

The catenary is judged according to the mechanical parameters:

If the mechanical parameters meet the preset design range, it is judged that the catenary of the part corresponding to the observation time is working normally;

If the mechanical parameters do not meet the preset design range, it is determined that the part of the catenary has a potential failure.

The above-mentioned railway catenary measurement method and catenary measurement system based on radar system, by installing a radar on both sides of the railway line, one of which is the main equipment radar (referred to as the main radar), and the other is the slave equipment radar ( Slave radar for short), under the control of the main control device, the two radars work synchronously, collect radar echoes of the same target at the same time and different viewing angles, and perform pulse compression, and then identify the peak position of the catenary in the pulse compression image, Then, the time difference interference technology is used to interferometrically process the wave peak complex scattering data, and the displacements of the catenary relative to the two radars are obtained respectively. The mechanical parameters of the catenary are estimated by spectral analysis of the lead and pull-out values. This method has the advantages of remote non-contact, high measurement accuracy, high efficiency and real-time performance, and convenient operation and deployment.

Description of drawings

1 is a schematic flowchart of a method for measuring a railway catenary based on a radar system in one embodiment;

2 is a schematic structural diagram of a catenary measurement system in one embodiment;

3 is a schematic diagram of a geometric model of a railway catenary pantograph in one embodiment;

Fig. 4 is a three-dimensional schematic diagram of the measurement point of the catenary measured by the master and the slave radar in one embodiment;

FIG. 5 is a schematic diagram of local coordinates of a catenary measurement scene in one embodiment.

Detailed ways

In order to make the purpose, technical solutions and advantages of the present application more clearly understood, the present application will be described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application, but not to limit the present application.

As shown in Figure 1-2, a radar system-based railway catenary measurement method is provided. The method is applied to the catenary measurement system. The catenary measurement system includes a master radar, a slave radar and a master control device that communicate with each other. The radar and the slave radar are distributed on both sides of the railway, and the connection between the two is perpendicular to the center line of the railway.

The railway catenary measurement method specifically includes the following steps:

Step S100, the master control device sends a work instruction to the master radar and the slave radar according to a preset synchronization scheme;

Step S110, the master radar and the slave radar transmit measurement signals to the same measurement point of the catenary according to the work instruction, and send the received radar echo signals to the master control device;

Step S120, the main control device performs pulse compression according to the radar echo signal at the initial observation time sent by the main radar and the slave radar respectively to obtain corresponding pulse compression images, and respectively identifies the peak positions of the catenary in each pulse compression image, and acquiring the wave peak complex scattering data corresponding to the wave peak position;

Step S130, extracting the actual coordinates of the main radar and the subordinate radar from the preset local coordinate system, and calculating according to the actual coordinates and the corresponding peak complex scattering data to obtain the difference between the catenary and the main radar and the subordinate radar at the initial observation time. The initial distance of and the initial coordinates of the catenary;

In step S140, two sets of complex scattering observation vectors corresponding to the main radar and the slave radar are obtained according to the radar echo data at multiple observation times, and a time difference interference method is used to obtain the catenary at each observation time according to the two sets of complex scattering observation vectors. relative to the displacement between the master radar and the slave radar;

Step S150, according to the actual coordinates of the main radar and the subordinate radar, the initial coordinates of the catenary, the initial distance between the catenary and the main radar and the subordinate radar respectively, and the relative position of the catenary at each observation moment. The displacement between the master radar and the slave radar is based on the formula for finding the distance between two points to construct the equations of the change of the lead height and the change of the pull-out value of the catenary as unknowns, and solve it to obtain the change of the lead-to-height and the change of the pull-out value. quantity;

In step S160, the mechanical parameters of the catenary are obtained by spectrum analysis according to the variation of the lead height and the variation of the pull-out value.

The present application provides a catenary measurement method used in a railway catenary scenario as shown in FIG. 3 , which is used to perform real-time dynamic telemetry on various key technical indicators of the catenary, wherein the key technical indicators include contact wire conductance, Geometric parameters such as pull-out value, mechanical parameters such as catenary tension, dynamic amplitude, etc.

In this embodiment, the railway catenary measurement method is applied to a catenary measurement system. The catenary measurement system uses radar as the main body to measure the catenary, and the radar echo signal is measured in the main control device. After corresponding processing, the key technical indicators of the catenary at the current moment are obtained, so as to realize the purpose of detecting the real-time status of the railway catenary.

In this embodiment, the main control device may be an upper computer.

In this embodiment, the catenary measurement system includes two radars respectively arranged outside the railway line, one of which is used as the main radar, and the other is used as the slave radar. When arranging the two radars on site, make sure that there is no obstruction between the radar and the catenary cable being observed, and adjust the radar antenna beam direction so that the center of the radar beam is aligned with the catenary cable.

In order to improve the measurement accuracy of the catenary, and within the allowable azimuth, the straight-line distance between the two radars should be controlled as large as possible. In some embodiments, the distance between the two radars may be around 10 meters.

Moreover, according to the radar principle, the long catenary cable has the strongest scattering on the normal plane of the measurement point, and it is necessary to further control the positions of the two radars so that the connecting line AB of the two is perpendicular to the catenary cable, as shown in Figure 4.

In steps S100-S110, the main control device sends work instructions to the two radars respectively, so that the two radars transmit measurement signals to the measurement points of the same catenary according to the work instructions, and then send the received radar echo signals to the master device. Afterwards, the respectively received radar echo data are processed in the main control device.

Since the catenary is relatively close to the master and slave radars, the two radars should adopt the broadband coherent continuous wave system. The two radars are similar in structure to the conventional ultra-short-range radar and the one-dimensional deformation measurement radar. The radar works synchronously under the control of the main control device. In order to prevent the co-frequency interference of the two radars from affecting the measurement accuracy, the main control device can send corresponding work instructions to make the measurement work under two different synchronization schemes.

In this embodiment, the preset synchronization scheme includes a first synchronization scheme and a second synchronization scheme.

The first synchronization scheme includes controlling the master radar and the slave radar to transmit measurement signals with waveforms of different frequencies or different codes at the same time.

Specifically, the transmission waveforms of the master and slave radars can be distinguished in terms of frequency or coding method. The master control device controls the two radars to work on different frequencies through instructions, or uses different coding transmission waveforms, while the two radars use The same pulse repetition frequency was measured.

Further, the measurement sequence can be generated by the master radar and transmitted to the slave radar, so that both work in the same measurement sequence. Alternatively, two radars can independently generate time sequences, work under their respective time sequences, and then mark the measured radar echo signals with sampling time marks, and finally perform data time registration on the main control device.

Wherein, the second synchronization scheme includes controlling the master radar and the slave radar to alternately transmit measurement signals whose waveforms are the same frequency and the same code.

Specifically, when the working frequencies and coding methods of the two radars are the same, mutual interference can be avoided by working in a time-sharing manner. The measurement sequence is generated by the master radar, and the working sequence is transmitted to the slave radar through wired or wireless channels. Through the timing design, the master and slave radars work alternately to avoid interference.

In this embodiment, the bandwidth of the measurement signal transmitted by the master radar and the slave radar is greater than 500 MHz.

According to the "Code for Design of Railway Electric Traction Power Supply", the shortest chord length from the load-bearing cable to the catenary cable is about 0.3 meters, so the distance resolution of the two radars should be better than 0.3 meters. The bandwidth of the transmitted signal should be greater than 500MHz, otherwise it will not be able to effectively distinguish between the two cables on the contact line.

The main radar and the slave radar transmit measurement signals to the catenary at a certain pulse repetition frequency after receiving the work order. The wave data includes multiple signal data about the same measurement point on the catenary at different observation times. The distance between the two radars and the catenary and the initial position of the catenary can be determined through the received initial radar echo data.

In step S120, the main control device first performs pulse compression on the radar echo data received from the main radar and the slave radar respectively. Among them, the master and slave radars can use broadband radar signals including step frequency signals, phase encoded signals and chirp signals. Taking chirp signals as an example, the radar echo signals emitted by the two radars can be expressed as:

（1）

(1)

为脉冲内快采样时间，

为起始频率，

为线性调频扫频周期，

为调频斜率，

是虚数单位，

为发射信号幅度，对形变估计的影响较小，在后续表达式中将其省略，矩形函数

。In formula (1),

is the fast sampling time within the pulse,

is the starting frequency,

is the chirp frequency sweep period,

is the frequency modulation slope,

is an imaginary unit,

is the amplitude of the transmitted signal, which has little influence on the deformation estimation, and is omitted in the subsequent expressions. The rectangular function

.

In this embodiment, before pulse compression processing is performed on the radar echo signal, after it is received by frequency modulation, an intermediate frequency echo of a fixed frequency is received and output, and the frequency of the intermediate frequency echo is proportional to the distance from the catenary to the radar. Proportional to the digital radar echo signal after processing by the AD analog-to-digital conversion acquisition device. Finally, pulse compression is performed on the processed radar echo signal, and the result of pulse compression is:

（2）

(2)

表示FFT的长度，

表示中频回波的AD采样频率，

表示中频回波的AD采样点数。其中

表示电磁波从发射，照射到接触网电缆，最后再被雷达接收的双程传输延迟，假设接触网电缆的位置坐标为

，则接触网在主雷达的延迟为：

，接触网在从雷达中的延迟为：

。In formula (2),

represents the length of the FFT,

Indicates the AD sampling frequency of the IF echo,

Indicates the AD sampling points of the IF echo. in

Represents the two-way transmission delay of the electromagnetic wave from the launch, irradiation to the catenary cable, and finally being received by the radar. It is assumed that the position coordinates of the catenary cable are

, then the delay of the catenary in the main radar is:

, the delay of the catenary in the slave radar is:

.

为主雷达的坐标，

为从雷达的坐标。in,

are the coordinates of the primary radar,

for the coordinates from the radar.

；在从雷达中，接触网的脉冲压缩波峰位于

；其中，

表示四舍五入取整运算。After pulse compression: In the main radar, the pulse compression peak of the catenary is at

; in the slave radar, the pulse-compression peak of the catenary is located at

;in,

Indicates the rounding operation.

和

，其相位分别为

和

，由于其中的第二项远小于第一项，因此该相位可分别近似为

和

。The complex scattering values corresponding to the peaks are denoted as:

and

, whose phases are

and

, since the second term is much smaller than the first term, the phases can be respectively approximated as

and

.

In other embodiments, the pulse compression processing on the radar echo data may also be performed locally on the master radar and the slave radar, and then the pulse compression result is sent to the master control device for subsequent calculation, corresponding to steps S110 to S120 Adjusted to:

Step S110, the master radar and the slave radar transmit measurement signals to the same measurement point of the catenary according to the working instructions, and after receiving the radar echo signals, pulse-compress the radar echo signals respectively to obtain the compressed radar echo signals, and send it to the master device;

In step S120, the main control device converts the compressed radar echo signal at the initial observation time sent by the main radar and the slave radar into a pulse-compressed image, and identifies the peaks of the catenary in each of the pulse-compressed images. position, and obtain the wave peak complex scattering data corresponding to the wave peak position.

After pulse compression processing is performed on the echo data of each radar, the peak complex scattering data in each pulse compressed image is obtained, and then the data and the coordinate positions of the master and slave radars are used to analyze the relationship between the catenary and the master radar and the slave radar respectively at the initial observation time. initial distance between.

，坐标面由两个雷达和接触网测量点构成，坐标原点为铁路路面中心，y轴方向为垂直向上方向，x轴方向为接触网电缆垂直方向，通过定位设备（如差分北斗/GPS，全站仪等）测量主雷达的实际坐标值

和从雷达的实际坐标值

。In step S130, as shown in FIG. 5, a local coordinate system is established

, the coordinate plane is composed of two radar and catenary measurement points, the coordinate origin is the center of the railway road, the y -axis direction is the vertical upward direction, and the x -axis direction is the vertical direction of the catenary cable. station, etc.) to measure the actual coordinate value of the main radar

and the actual coordinate values from the radar

.

，初始时刻接触网络到从雷达的距离为

。Then, according to the subscript of the pulse compression peak position and the radar system parameters, the distance from the catenary cable to the main radar at the initial moment can be obtained as:

, the distance from the contact network to the radar at the initial moment is

.

After obtaining the initial distances between the catenary and the primary radar and the secondary radar respectively at the initial observation time, it includes:

According to the actual coordinates of the main radar and the initial distance between the main radar and the catenary, construct the first equation in which the initial coordinates of the catenary are unknowns;

According to the actual coordinates of the radar and the initial distance between the radar and the catenary, a second equation with the initial coordinates of the catenary as an unknown number is constructed;

Solve the first equation and the second equation to obtain the initial coordinates of the catenary.

Specifically, the first equation and the second equation can obtain the following equations:

（3）

(3)

In formula (3), since the actual coordinates of the main radar, the initial distance between the main radar and the catenary, the actual coordinates of the secondary radar, and the initial distance between the secondary radar and the catenary are all known numbers, the formula ( 3) Solve to obtain the coordinate value of the catenary at the initial observation time, that is, the initial position of the catenary.

In step S140, since a plurality of radar echo data corresponding to different times will be obtained when the catenary is measured, pulse compression processing can be performed on each radar echo data to obtain two sets of complex data corresponding to the master radar and the slave radar respectively. Scatter observation vector.

，在不同

时刻可以获得主雷达关于接触网电缆的一组复散射观测向量

，以及从雷达关于接触网电缆的一组复散射观测向量

。Specifically, it is assumed that the repeated measurement frequency of the two radars is

,in difference

A set of complex scattering observation vectors of the main radar about the catenary cable can be obtained at the moment

, and a set of complex scattering observation vectors from radar on catenary cables

.

Then, the time difference interference principle is used to estimate the radial deformation of the catenary cable relative to the initial position, that is, the displacement of the catenary relative to the master radar and the slave radar respectively.

。Among them, the displacement of the catenary cable relative to the main radar at each observation moment is:

.

。Among them, the displacement of the catenary cable relative to the slave radar at each observation moment is:

.

As shown in Figure 5, where point A is the initial position of the catenary at the initial observation time t _n , and the initial position is the previous observation time, then point B is the current position of the catenary at the current observation time t _n+1 Location. Since the displacement of the catenary is caused by the change of the lead height in the Y-axis direction and the change of the pull-out value in the X-axis direction, it can be compared with the main radar and the slave radar respectively according to the initial position of the catenary. When the catenary is at the current position, the position formula between the main radar and the slave radar is derived from the formula of the distance between them, and the variation of the lead height and the variation of the pull-out value are solved as unknown quantities.

Among them, according to the actual coordinates of the main radar, the initial coordinates of the catenary, the change of the guide height, the change of the pull-out value, the initial distance between the main radar and the catenary, and the displacement of the catenary relative to the main radar at the current observation time , construct the first distance equation between the main radar and the catenary at the current observation moment;

Among them, according to the actual coordinates of the slave radar, the initial coordinates of the catenary, the variation of the guide height, the change of the pull-out value, the initial distance between the slave radar and the catenary, and the displacement of the catenary relative to the slave radar at the current observation time , and construct the second distance equation between the radar and the catenary at the current observation moment.

It is obtained by combining the first distance equation and the second distance equation:

（4）

(4)

为公式（3）的解，也就是接触网在初始位置的坐标，

和

分别为导高变化量以及拉出值变化量，而

和

为两个雷达的观测距离存在的位移变化量。而公式（4）中两方程的右边实际就是图5中

和

的值。In formula (4),

is the solution of formula (3), that is, the coordinates of the catenary at the initial position,

and

are the variation of the lead height and the variation of the pull-out value, respectively, and

and

It is the displacement variation that exists between the observation distances of the two radars. The right side of the two equations in formula (4) is actually in Figure 5

and

value of .

The first distance equation and the second distance equation are solved at multiple observation times respectively, and the variation of the lead height and the variation of the pull-out value corresponding to each observation moment are obtained.

，接触网相对于初始位置

，导高和拉出值分别存在变量。Specifically, at other times

, the catenary relative to the initial position

, and there are variables for the lead-up and pull-out values, respectively.

When solving the lead-up variable and the pull-out value variable in formula (4), the two equations of formula (4) and formula (3) are subtracted to obtain a new set of equations:

（5）

(5)

和拉出值变化量

较小，可知方程组左边第二项和第四项分别小于第一项和第三项，方程组右边第二项远小于第一项，因此该方程组简化为：In Equation (5), due to the lead change

and pull-out value change

It can be seen that the second term and fourth term on the left side of the equation system are smaller than the first term and the third term respectively, and the second term on the right side of the equation system is much smaller than the first term, so the equation system is simplified as:

（6）

(6)

According to formula (6), the estimates of the change of lead height and the change of pull-out value can be obtained as:

（7）

(7)

According to formula (7), the change of lead height and the change of pull-out value corresponding to each observation time can be solved.

以及拉出值冲击振幅（左右摆动量）

。In step S160 , the mechanical parameters of the catenary obtained by spectrum analysis according to the variation of the lead height and the change of the pull-out value include: finding the maximum lead-height among the changes of the lead-up height and the change of the pull-out value corresponding to each observation time. The change amount and the maximum pull-out value change amount, and according to the maximum lead-up value change amount and the maximum pull-out value change amount, respectively, the lead-up impact amplitude (up and down lift) is calculated accordingly.

And the pull-out value shock amplitude (left-right swing amount)

.

以及

分别为：in,

as well as

They are:

（8）

(8)

Fourier transform is performed on the lead height variation corresponding to each observation time to obtain the lead height change spectrum, and the fundamental frequency component is extracted from the lead height change spectrum. According to the fundamental frequency component and the tension formula of the catenary cable, the catenary cable is The tensile force of the cable, the linear density of the string cable and the equivalent length of the catenary cable are estimated to obtain the estimated tensile force, linear density and equivalent length.

，张力

可按照公式

。其中， q是弦索的线密度，

表示接触网电缆的等效长度。Among them, the fundamental frequency component is

,tension

according to the formula

. where q is the linear density of the string,

Indicates the equivalent length of the catenary cable.

In this embodiment, the method for measuring the railway catenary further includes: after performing spectrum analysis according to the variation of the lead height and the variation of the pull-out value to obtain the mechanical parameters of the catenary:

The catenary is judged according to the mechanical parameters:

If the mechanical parameters conform to the preset design range, it is judged that the catenary of the part corresponding to the observation time is working normally;

If the mechanical parameters do not meet the preset design range, it is judged that this part of the catenary has potential failures.

In the above railway catenary measurement method based on radar system, one radar is installed on both sides of the railway line, one of which is the main equipment radar (referred to as the main radar), and the other is the slave equipment radar (slave radar). The two radars work synchronously under the control of the main control computer or the main radar, collect the radar echoes of the same target at the same time and different viewing angles, and perform pulse compression, and then identify the peak position of the catenary in the pulse compression image, and then use the time The differential interferometric technique interferometrically processes the complex scattering data of the wave peaks, and obtains the displacement of the catenary relative to the two radars, respectively, and then obtains the guide height deformation and the pull-out value deformation of the catenary by solving the binary equation. Spectral analysis of pull-out values estimates the mechanical parameters of the catenary and judges the health of the catenary. The method has the advantages of remote non-contact, high measurement accuracy, high efficiency and real-time performance, and convenient operation and deployment. And it has no impact on train operation, and has excellent environmental adaptability. It can be widely used for real-time monitoring of the catenary of conventional railways and high-speed railways to ensure the safety of railway operation, and can also be used to provide scientific research and technical support for the design of the next generation of high-speed railways and the establishment of relevant standards.

It should be understood that although the various steps in the flowchart of FIG. 1 are shown in sequence according to the arrows, these steps are not necessarily executed in the sequence shown by the arrows. Unless explicitly stated herein, the execution of these steps is not strictly limited to the order, and these steps may be performed in other orders. Moreover, at least a part of the steps in FIG. 1 may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily executed and completed at the same time, but may be executed at different times. The execution of these sub-steps or stages The sequence is also not necessarily sequential, but may be performed alternately or alternately with other steps or sub-steps of other steps or at least a portion of a phase.

In one embodiment, a catenary measurement system is provided, the catenary measurement system includes a master radar, a slave radar and a master control device that communicate with each other, the master radar and the slave radar are respectively distributed on both sides of the railway, and both The connection between them is perpendicular to the railway centerline;

The master control device sends work orders to the master radar and the slave radar according to the preset synchronization scheme;

The main radar and the slave radar transmit measurement signals to the same measurement point of the catenary according to the work instruction, and send the received radar echo signals to the main control device;

The main control device performs pulse compression according to the main radar and the radar echo signal at the initial observation time sent from the radar to obtain corresponding pulse compression images, and respectively identifies the peak positions of the catenary in each pulse compression image and obtains the wave peaks. The peak complex scattering data corresponding to the position;

The actual coordinates of the master radar and the slave radar are extracted from the preset local coordinate system, and the calculation is performed according to the actual coordinates and the corresponding wave peak complex scattering data to obtain the relationship between the catenary and the master radar and the slave radar at the initial observation time. The initial distance, and the initial coordinates of the catenary;

According to the radar echo data of multiple observation times, two sets of complex scattering observation vectors corresponding to the main radar and the secondary radar are obtained respectively, and according to the two sets of complex scattering observation vectors, the time difference interference method is used to obtain the relative relationship between the catenary and the main radar at each observation time. amount of displacement between the radar and the slave radar;

According to the actual coordinates of the main radar and the subordinate radar, the initial coordinates of the catenary, the initial distance between the catenary and the main radar and the subordinate radar, and the displacement of the catenary relative to the main radar and the subordinate radar at each observation moment based on the formula for finding the distance between two points, construct the equations in which the change of lead height and the change of pull-out value of the catenary are unknowns, and solve it to obtain the change of lead-to-height and the change of pull-out value;

The mechanical parameters of the catenary are obtained by spectrum analysis according to the variation of the lead height and the variation of the pull-out value.

In one of the embodiments, the main control device further includes: after performing spectrum analysis according to the variation of the lead height and the variation of the pull-out value to obtain the mechanical parameters of the catenary:

The catenary is judged according to the mechanical parameters:

If the mechanical parameters conform to the preset design range, it is judged that the catenary of the part corresponding to the observation time is working normally;

If the mechanical parameters do not meet the preset design range, it is judged that this part of the catenary has potential failures.

Those of ordinary skill in the art can understand that all or part of the processes in the methods of the above embodiments can be implemented by instructing relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage In the medium, when the computer program is executed, it may include the processes of the above-mentioned method embodiments. Wherein, any reference to memory, storage, database or other medium used in the various embodiments provided in this application may include non-volatile and/or volatile memory. Nonvolatile memory may include read only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous chain Road (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM) and so on.

The technical features of the above embodiments can be combined arbitrarily. In order to make the description simple, all possible combinations of the technical features in the above embodiments are not described. However, as long as there is no contradiction in the combination of these technical features It is considered to be the range described in this specification.

The above-mentioned embodiments only represent several embodiments of the present application, and the descriptions thereof are specific and detailed, but should not be construed as a limitation on the scope of the invention patent. It should be pointed out that for those skilled in the art, without departing from the concept of the present application, several modifications and improvements can be made, which all belong to the protection scope of the present application. Therefore, the scope of protection of the patent of the present application shall be subject to the appended claims.

Claims (9)

1. The method is characterized by being applied to a contact network measuring system, wherein the contact network measuring system comprises a main radar, a secondary radar and a main control device which are communicated with each other, the main radar and the secondary radar are respectively distributed on two sides of a railway, and a connecting line between the main radar and the secondary radar is perpendicular to a central line of the railway;

the railway contact network measuring method comprises the following steps:

the master control device sends a working instruction to the master radar and the slave radar according to a preset synchronization scheme;

the master radar and the slave radar transmit measurement signals to the same measurement point of the overhead line system according to the working instruction, and transmit the received radar echo signals to the master control device, or respectively perform pulse compression on the received radar echo signals to obtain compressed radar echo signals, and then transmit the compressed radar echo signals to the master control device;

the main control device respectively performs pulse compression according to radar echo signals at the initial observation time sent by a main radar and a slave radar to obtain corresponding pulse compression images, or the main control device directly converts the compressed radar echo signals received from the main radar and the slave radar into pulse compression images, respectively identifies the peak positions of the contact network in each pulse compression image, and acquires peak complex scattering data corresponding to the peak positions;

extracting actual coordinates of the main radar and the slave radar from a preset local coordinate system, and calculating according to each actual coordinate and corresponding peak complex scattering data to obtain an initial distance between the catenary and the main radar and the slave radar respectively at an initial observation moment and initial coordinates of the catenary;

respectively obtaining two groups of complex scattering observation vectors corresponding to the main radar and the slave radar according to radar echo data of a plurality of observation moments, and obtaining displacement of the overhead line system relative to the main radar and the slave radar at each observation moment by adopting a time difference interference method according to the two groups of complex scattering observation vectors;

according to the actual coordinates of the main radar, the actual coordinates of the auxiliary radar, the initial coordinates of the overhead line system, the initial distance between the overhead line system and the main radar and the initial distance between the overhead line system and the auxiliary radar respectively, and the displacement of the overhead line system relative to the main radar and the auxiliary radar at each observation moment, an equation with the overhead line system height variation and the pull-out value variation as unknowns is constructed based on a distance solving formula between two points, and the overhead line system height variation and the pull-out value variation are solved;

and carrying out spectrum analysis according to the lead height variation and the pull-out value variation to obtain the mechanical parameters of the overhead line system.

2. The radar system based railway catenary measurement method according to claim 1, wherein the preset synchronization scheme comprises a first synchronization scheme and a second synchronization scheme;

the first synchronization scheme comprises controlling the main radar and the auxiliary radar to transmit measurement signals with different frequencies or different codes at the same moment;

the second synchronization scheme includes controlling the master radar and the slave radar to alternately transmit measurement signals having the same frequency and the same code.

3. The method for measuring the railway contact network based on the radar system as claimed in claim 1, wherein the bandwidth of the measurement signals transmitted by the main radar and the secondary radar is more than 500 MHz.

4. The method for measuring the railway catenary based on the radar system as claimed in claim 1, wherein the method comprises the steps of extracting actual coordinates of the main radar and the secondary radar from a preset local coordinate system, calculating according to each actual coordinate and corresponding peak complex scattering data, and obtaining an initial distance between the catenary and the main radar and the secondary radar respectively at an initial observation time and an initial coordinate of the catenary, wherein after obtaining the initial distance between the catenary and the main radar and the secondary radar respectively at the initial observation time, the method comprises the following steps:

constructing a first equation with the initial coordinate of the overhead line system as an unknown number according to the actual coordinate of the main radar and the initial distance between the main radar and the overhead line system;

constructing a second equation with the initial coordinate of the overhead line system as an unknown number according to the actual coordinate of the slave radar and the initial distance between the slave radar and the overhead line system;

and solving by using a first equation and a second equation to obtain the initial coordinate of the overhead line system.

5. The method for measuring the railway overhead line system based on the radar system as claimed in claim 1, wherein the step of constructing an equation with the overhead line system variation and the pull-out value variation as unknowns based on a distance solving formula between two points according to the actual coordinates of the main radar and the slave radar, the initial coordinates of the overhead line system, the initial distances between the overhead line system and the main radar and the slave radar respectively, and the displacement of the overhead line system relative to the main radar and the slave radar at each observation moment, and solving to obtain the overhead line variation and the pull-out value variation comprises the steps of:

setting the initial observation time as the previous observation time;

constructing a first distance equation between the main radar and the overhead contact system at the current observation time according to the actual coordinates of the main radar, the initial coordinates of the overhead contact system, the variation of the guide height, the variation of the pull-out value, the initial distance between the main radar and the overhead contact system and the displacement of the overhead contact system relative to the main radar at the current observation time;

constructing a second distance equation between the slave radar and the overhead contact system at the current observation time according to the actual coordinates of the slave radar, the initial coordinates of the overhead contact system, the variation of the guide height, the variation of the pull-out value, the initial distance between the slave radar and the overhead contact system and the displacement of the overhead contact system relative to the slave radar at the current observation time;

and solving the first distance equation and the second distance equation at a plurality of observation moments respectively to obtain the derivative variation and the pull-out value variation corresponding to each observation moment.

6. The method for measuring the railway overhead line system based on the radar system of claim 5, wherein the obtaining of the mechanical parameters of the overhead line system by performing spectrum analysis according to the variation of the overhead line system and the variation of the pull-out value comprises:

respectively finding out the maximum lead height change amount and the maximum pull-out value change amount from the lead height change amount and the pull-out value change amount corresponding to each observation moment, and respectively calculating and correspondingly obtaining a lead height impact amplitude and a pull-out value impact amplitude according to the maximum lead height change amount and the maximum pull-out value change amount;

and carrying out Fourier transform according to the lead height variation corresponding to each observation time to obtain a lead height variation frequency spectrum, extracting a fundamental frequency component from the lead height variation frequency spectrum, and estimating the tension of the contact network cable, the linear density of the chord cable and the equivalent length of the contact network cable according to the fundamental frequency component and a tension formula of the contact network cable to obtain a tension estimated value, a linear density estimated value and an equivalent length estimated value.

7. The method for measuring the railway overhead line system based on the radar system according to any one of claims 1 to 6, wherein the method for measuring the railway overhead line system further comprises the following steps of after obtaining mechanical parameters of the overhead line system through spectrum analysis according to the variation of the overhead line system and the variation of the pull-out value:

judging the contact network according to the mechanical parameters:

if the mechanical parameters accord with a preset design range, judging that the part of the contact net corresponding to the observation moment works normally;

and if the mechanical parameters do not accord with the preset design range, judging that the part of the contact network has potential faults.

8. The contact network measuring system based on the radar system is characterized by comprising a main radar, a secondary radar and a main control device which are communicated with each other, wherein the main radar and the secondary radar are respectively distributed on two sides of a railway, and a connecting line between the main radar and the secondary radar is vertical to the central line of the railway;

the master control device sends a working instruction to the master radar and the slave radar according to a preset synchronization scheme;

the master radar and the slave radar transmit measurement signals to the same measurement point of the overhead line system according to the working instruction, and transmit the received radar echo signals to the master control device;

the main control device respectively performs pulse compression according to radar echo signals at the initial observation time sent by a main radar and a slave radar to obtain corresponding pulse compression images, respectively identifies the peak position of the contact network in each pulse compression image and acquires peak complex scattering data corresponding to the peak position;

extracting actual coordinates of the main radar and the slave radar from a preset local coordinate system, and calculating according to each actual coordinate and corresponding peak complex scattering data to obtain initial distances between the catenary and the main radar and the slave radar respectively at an initial observation moment and initial coordinates of the catenary;

respectively obtaining two groups of complex scattering observation vectors corresponding to the main radar and the slave radar according to radar echo data of a plurality of observation moments, and obtaining displacement of the overhead line system relative to the main radar and the slave radar at each observation moment by adopting a time difference interference method according to the two groups of complex scattering observation vectors;

according to the actual coordinates of the main radar, the actual coordinates of the auxiliary radar, the initial coordinates of the overhead line system, the initial distance between the overhead line system and the main radar and the initial distance between the overhead line system and the auxiliary radar respectively, and the displacement of the overhead line system relative to the main radar and the auxiliary radar at each observation moment, an equation with the overhead line system height variation and the pull-out value variation as unknowns is constructed based on a distance solving formula between two points, and the overhead line system height variation and the pull-out value variation are solved;

and carrying out spectrum analysis according to the lead height variation and the pull-out value variation to obtain the mechanical parameters of the overhead line system.

9. The catenary measurement system according to claim 8, wherein the main control device, after performing spectrum analysis according to the lead height variation and the pull-out value variation to obtain the mechanical parameters of the catenary, further comprises:

judging the contact network according to the mechanical parameters:

if the mechanical parameters accord with a preset design range, judging that the part of the contact net corresponding to the observation moment works normally;

and if the mechanical parameters do not accord with the preset design range, judging that the part of the contact network has potential faults.

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