The stability of China's high-speed rail is related to the Beidou satellite in the sky
Compared with traditional methods such as measuring with a gauge ruler or semi-automatic measurement with a total station, the Beidou inertial navigation vehicle has increased its operating efficiency by more than 20 times while ensuring measurement accuracy, greatly reducing measurement costs and field complexity.
On October 28, the State Council Information Office held a press conference on the economic performance of transportation in the first three quarters of 2020.
According to Wu Chungeng, spokesperson of the Ministry of Transport and director of the Policy Research Office, currently, about 6,986,100 road operating vehicles have been installed and used the Beidou system.
The Ministry of Transport has issued a special plan for the application of Beidou satellites in the transportation industry, and policy guidance in key areas such as railways and highways is constantly being strengthened.
In the previous 10 days or so, engineers from the China Railway Fifth Survey and Design Institute Group Co., Ltd. (hereinafter referred to as the China Railway Fifth Institute) cooperated with engineering and technical personnel of Wuhan University to measure the geometric state of the independently developed Beidou inertial integrated navigation railway track The instrument (commonly known as the Beidou inertial navigation vehicle) was successfully used at the construction site of the Chaoyang Junction to Shunyi section of the Beijing-Shenzhen High-speed Railway, and completed the multi-round precision measurement task of nearly 50 kilometers of ballasted track.
This is the first time that the Beidou-3 global satellite navigation system has been engineered into the field of high-speed rail construction. It directly serves the fine adjustment of the orbit and ensures that the position and smoothness of the orbit strictly meet the design standards.
Then, how does the Beidou system, which is tens of thousands of kilometers away from the earth, "keep the pulse" of the traffic arteries laid on the ground?
What kind of measurement accuracy can be achieved?
Accurate measurement of various data to ensure smooth track
According to reports, passengers can "walk in the courtyard" in a high-speed rail car running at a speed of 350 kilometers per hour, and keep coins on the side of the car windows. This depends on the high-speed rail line's high smoothness.
Once the track is not smooth enough, it will cause system vibration of the rolling stock, which will have a direct impact on wheel-rail noise, wheel-rail interaction, ride comfort, safety, etc.
In order to ensure the smoothness of the track to the greatest extent, the staff needs to accurately obtain the three-dimensional position coordinates and track spacing of the track to achieve high-precision measurement of various geometric parameters such as orbit, height, gauge, and level.
"In simple terms, it is necessary to first determine the actual position of the track centerline through measurement, and obtain the deviation from the design position in the plane (orbit) and elevation (high and low) directions. Then according to this deviation, the adjustment amount is calculated." Said Rao Xiong, technical person in charge of the comprehensive application demonstration project of the Beidou railway industry in the Fifth Academy.
In the early construction and maintenance of railways, technicians needed to manually measure the track with a gauge ruler, which was very inefficient.
Later, use a special high-precision total station for orbit measurement.
The surveyor will temporarily set up a tripod on the centerline of the track, and then mount the high-precision total station on the tripod, measure the information of the selected sample points by photoelectric scanning, and then calculate the coordinate data of the rail, each sleeper needs Repeat once, only 200 meters can be measured in one hour.
With the rapid development of high-speed rail construction, track precision measurement technology is constantly evolving.
Inertial integrated navigation railway track geometric state measuring instrument, also called inertial navigation trolley, is currently the most common measurement method.
Rao Xiong said that the inertial navigation car mainly includes gyroscopes, accelerometers, inertial navigation systems, and satellite positioning systems.
When measuring, the staff needs to push the inertial navigation car on the track, because the car is moving in three-dimensional space, so you can establish the space coordinate axis and add the data collected in the 3 directions during the measurement process. The computer calculates the spatial coordinates of each part of the track, and then further calculates whether there is an abnormal deviation in the continuous point value.
Rao Xiong said that with inertial navigation technology, the track geometry at any position can be accurately positioned with one device, and the measurement data can be processed in a one-stop integrated manner, which significantly improves operation efficiency while ensuring accuracy.
This also means that after the railway track data acquisition mode is handed over to the inertial navigation car, automatic acquisition and automatic data processing can be realized, and there is basically no need to do too much on-site operations.
With Beidou, the measurement accuracy is higher and the operation efficiency is increased by 20 times
On the basis of the technology and products accumulated in the early stage, the Fifth Railway Institute and Wuhan University jointly formed a research and development team to carry out the localized transformation and upgrading of the inertial navigation trolley commonly used in railways.
The newly developed Beidou inertial navigation vehicle integrates a number of domestic technologies, and the biggest feature is the use of domestic Beidou chips.
"The project integrates domestic satellite navigation receivers and inertial navigation systems that support Beidou-3 to replace traditional orbit precision measurement methods," said Rao Xiong.
Beidou navigation and inertial navigation can complement each other to improve the overall navigation accuracy, navigation performance and spatial calibration capabilities of the system.
It is understood that Beidou's precise positioning function combined with the powerful angle and position estimation capabilities of inertial navigation can achieve continuous movement measurement. The staff can push the trolley all the way to perform measurement calculations at the same time, and the measurement efficiency can reach about 5 kilometers per hour of walking. Even faster.
Because of the unique constellation design of the Beidou system, there are more Beidou satellites over China, so the measurement accuracy is higher, and the anti-interference and reliability are stronger.
In addition, Beidou's high-precision measurement capabilities can effectively help reduce measurement errors.
Under normal circumstances, the data calculation of the inertial navigation system is an integral process. The whole process is coupled with the errors of the positioning gyroscope and accelerometer. The rapid accumulation of errors will have a certain impact on the calculation results.
"Using Beidou or other satellite positioning technology can effectively suppress the accumulation of errors, so that the entire system can be maintained at a high-precision level for a long time." Rao Xiong said, compared with the use of a gauge ruler for measurement or semi-automatic measurement with a total station Compared with traditional methods, the Beidou inertial navigation vehicle has increased its operating efficiency by more than 20 times while ensuring measurement accuracy, greatly reducing measurement costs and field complexity.
"Using the domestic Beidou chip, the core sensor of our inertial navigation car is completely localized, becoming autonomous and controllable, and getting rid of dependence on other navigation facilities." Rao Xiong said.
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These railway "black technologies" are all related to Beidou
In this year’s “Outline of the Advanced Railway Planning for a Powerful Transportation Country in the New Era” issued by China National Railway Group Co., Ltd., it is clearly stated that by 2035, it will be the first to complete the intelligent railway network; The "super brain" that integrates heaven and earth.
In fact, Beidou, which seems to be far above Jiuxiao, has come to us. Many "black technologies" that have been successfully used in railway construction are all related to Beidou.
Precise positioning of China-Europe Express
The distance between China-Europe Express trains is more than 10,000 kilometers, and it often passes through no man's land. There is no mobile communication signal in those areas. When the train passes through these areas, the signal is lost and there is no way to save it.
Now that the Beidou positioning system is installed, the train's operating data can be recorded in real time, and after the train runs to a place where there is a mobile communication signal, it will be sent back to the China-Europe Railway Operation Service Center to ensure the integrity of the information.
At present, China-Europe Express trains are connected to 72 cities in 21 countries. The Beidou satellite can track the trajectory of the China-Europe Express, and the positioning is accurate to within 10 meters.
Release warning information 24/7
The Beidou infrastructure monitoring application can perform real-time automated high-precision monitoring of railway equipment and facilities and the environment along the line, collect raw monitoring data, and preprocess the data to achieve functions such as the solution and analysis of monitoring data and the release of early warning information.
For example, 5 key bridges and 6 key slopes along the Haoji Railway have adopted Beidou-based high-precision displacement and deformation monitoring technology to monitor the infrastructure for long-term, which can ensure the real-time and continuity of monitoring and effectively obtain trends. Information can also guarantee high precision and automation, and increase protection for line safety.
Timely control locomotive status
The China Locomotive Remote Monitoring and Diagnosis System (CMD system) can transmit locomotive faults, alarm information, and locomotive position information to the ground system in real time through the Beidou satellite navigation system to complete the collection, processing and transmission of vehicle-to-ground and ground-to-vehicle data.
Functional departments can timely grasp locomotive failures, alarm information, locomotive location information and locomotive work quality status.
The convenience and effectiveness of locomotive quality control by locomotive crew have been greatly improved.
Our reporter Jiao Yang