Application of high-speed railway signal system based on wireless communication technology
abstract
High-speed railway signal system is the basic guarantee for the safe and high-density operation of high-speed trains. The application of wireless communication technology in railway signal system not only reduces the cost of high-speed railway signal system, but also ensures the safety of high-speed railway. With the progress of science and technology, the high-speed railway is developing in the direction of intelligence and informatization, which puts forward stricter requirements for the technical field of wireless communication. In order to adapt to the rapid development of high-speed railway, all countries are committed to studying a new generation of railway signal system based on wireless communication technology. This paper introduces the development of foreign wireless communication system in high-speed railway signal system, analyzes the characteristics and existing problems of adopting wireless communication technology in high-speed railway signal system, and probes into the application of wireless communication technology in high-speed railway signal system.
Keywords wireless communication; High-speed railway signal system
In the whole high-speed railway project, although the signal system accounts for a small proportion of the total investment, its role is very critical. Due to the harsh transmission environment of track circuit, low information transmission rate and high equipment maintenance cost, the train control system based on track circuit can no longer meet the rapid development requirements of high-speed railway. In 1980s, foreign countries began to study the railway signaling system TBS (Transmission Based Signaling) based on wireless communication technology, hoping to improve railway management function, shorten train interval, save energy and reduce system cost through the application of wireless communication technology. In the 1995 TBS International Conference, the participants analyzed the feasibility of the application of wireless communication technology in railway signal system, pointed out the positive impact that wireless communication technology may bring to railway signal system, and predicted that TBS would become the development direction of railway signal system in the future.
1 development of TBS abroad
Development of 1. 1 TBS in North America
1983, the American Railway Association and the Canadian Railway Association jointly proposed the advanced train control system ATCS based on wireless communication. ATCS mainly obtains the accurate position and speed information of the train through digital data communication means and advanced microprocessor, and carries out safety control on the train. The application of ATCS not only avoids the installation of many ground signal equipment and saves the system cost, but also eliminates the signal blind area and improves the safety factor of the train. ATCS consists of five sub-control systems: central control system, wireless data communication network, vehicle-mounted equipment, roadside equipment and mobile terminal of line maintenance personnel. Its system structure design and functional module division lay the foundation for the future railway signal system based on wireless communication. With the development of wireless communication technology, after ATCS, many railway signal systems based on wireless communication have appeared in North America, among which ARES can provide a very reliable means of checking and balancing, which greatly reduces the errors caused by human operation errors and makes the train operation safer. In addition, PTS, PTC, AATC, ITCS and other systems are also famous.
1.2 development of TBS in Europe
1992, the European Railway Research Institute under the International Railway Union put forward a set of European railway transportation management system, including ticket sales, railway interconnection among countries and so on, in which ETCS is a very important part. Before the European Commission established the standardized European railway control system project ETCS, the railway standards and modes of European countries were different, and the gauge, signal equipment and power supply equipment were also different, so each country could only use its own ATP and ATC system. The differences of railway systems in different countries make it difficult for European railways to form continuous transportation. After the establishment of the standardized European railway control system project ETCS, railways in various countries began to be standardized according to unified standards, gradually replacing different automatic train control systems and protection systems in various countries. The goal of ETCS is to realize the unification of European railways, improve the interoperability of railways in various countries, and standardize the functions and equipment of railway control systems.
Development of 1.3 TBS in Japan
In the development of Japanese railway signal system, ATS, current ATC, digital ATC, computer and wireless communication auxiliary information control system appeared successively. Among them, the current ATC, as a train overspeed protection system, protects the safety of trains with good automatic braking function. However, the system uses the strongest automatic braking when working, which affects the comfort of passengers. 1987, Japan began to study the railway signal system based on wireless communication, which laid a solid foundation for the emergence of CARAT. The use of CARAT enables the train to continuously measure its own position and running speed, and enables the ground system to know the running situation of the train well, thus ensuring the transportation safety of the train.
Characteristics and problems of 2 TBS
On the high-speed railway with relatively high speed, when the distance is close, wireless communication technologies such as infrared and Bluetooth can be used to control the train. When the distance is far away, the speed and position of the train can be determined by global positioning control system, beacon, axle counting device and so on. The on-board computer can send the speed and position information of the train to the dispatching control computer through the wireless transceiver, and then the information such as the maximum allowable speed of the train is sent back to the train computer through wireless communication after being processed by the dispatching control computer. Train drivers can carry out corresponding operations according to the reminder of the on-board computer. If the train driver fails to respond in time, the information control system can also reduce the speed to the allowable range by itself.
2. Characteristics of1TBS
(1) In TBS, the main control center can adjust the train operation through the on-board computer according to the running state and operation state of the train, which increases the management function of the high-speed railway signal system, ensures the safety of the train and improves the passing capacity of the railway line.
(2) Under the control of the wireless communication signal system, the reliable information of the train and the ground is increased, the train runs more stably, unnecessary acceleration and braking are avoided, energy is saved, and passengers are more comfortable.
(3) The application of wireless communication technology saves a lot of ground signal equipment and greatly reduces the cost of equipment installation, maintenance and repair.
(4) The wireless communication signal system has strong adaptability, and the train speed can be improved by software adjustment, and the train diagram can be automatically adjusted, which greatly improves the railway transportation management ability.
(5) The wireless communication signal system can also realize the train locking control through the two-way information channel between the train and the ground.
2.2 TBS problem
(1) The track circuit used in high-speed railway signal system can only use low information transmission frequency, and the transmission environment is harsh, so it is difficult to make the coding transmission rate meet the requirements of high-speed railway.
(2)TBS receives data information through loop equipment and answering equipment, and the train operation may be delayed, which will adversely affect the train operation.
(3) As a two-way information channel between vehicles and the ground, cables and wires between tracks have a large amount of information and strong anti-interference ability, but the equipment cost is high and the anti-theft ability is poor. Once lost, the consequences are very serious.
3. Application of wireless communication technology in high-speed railway signal system 3. 1 Microcomputer Interlocking
The feasibility of using wireless communication technology in microcomputer interlocking needs further study, but ATCS proposes that the locked state of detected switches and signals can be sent to the main control center, and the control commands of the main control center can be received by the wayside interface unit, so as to control the actions of a group of switches and signals. In addition, the wayside interface unit can contact the control center through wireless channels and connect the field devices through cables to detect and control some auxiliary subsystems. At present, it seems that the application of wireless communication technology in microcomputer interlocking field equipment may increase some investment, and there are many turnouts in large stations and yards, which have great interference, but there are still good development prospects.
3.2 Centralized scheduling
In the centralized dispatching system, the dispatching center should understand the train operation according to the occupancy of the station to the departure line and the block partition, and arrange the route according to the obtained information. Using TBS, the control system can accurately know the position and speed of the train, and send train control commands according to the signal system along the line to ensure the high-speed, safe and stable operation of the train in the shortest practical interval. Wireless communication technology endows the train with two-line data communication with the control center, which brings great convenience to the train operation and realizes the automation of traffic command.
3.3 repeater
In the actual operation of high-speed railway, it is impossible for me to set up this kind of wireless communication base station in all high-speed railways, which not only increases the equipment investment, but also makes the wireless communication railway signal system lose its real significance. With the repeater, the base station can receive and send some RF signals through the repeater, so that the base station can not only manage the station area in the base station area, but also manage some vehicles and lines managed by the repeater.
3.4 Improve the traffic efficiency of crossings.
In order to improve the protection ability and passing efficiency of grade crossing and prevent unnecessary losses caused by wireless equipment failure, the main control center continuously inquires about the running status of grade crossing at intervals, and feeds back the inquiry information to the trains near grade crossing in time. In addition, the main control center can calculate the time when the train passes through the crossing through the received information of the train position and speed, and set the maximum allowable speed of the train and the reference of the train running route according to the actual situation. This not only ensures the safety of trains passing through grade crossing, but also greatly improves the efficiency of crossing.
3.5 Strengthen the protection of the maintenance office
When a section of high-speed rail needs maintenance, the maintenance department can input the maintenance point into the system through the mobile terminal, and the transmission of the train through the main control center can well understand the situation of the section. In actual operation, the train can run according to the learned maintenance point information. In addition, when the train approaches the maintenance point, the mobile terminal receives the alarm signal from the ground system to ensure that the train can stop in front of the maintenance section in time.
4 abstract
With the continuous development of high-speed railway, in order to ensure the safety of trains, advanced signal system has become the top priority of high-speed railway operation. In the high-speed railway information system, the application of wireless communication is still in its infancy. In the specific TBS planning, the interface between TBS and railway transportation management system should be fully considered, so that wireless communication technology can be fully utilized in the development of high-speed railway.
refer to
[1] Min Yaoxing. Present situation of train safety control system in China [J]. Harbin Railway Science and Technology Communication, 1997(04).
[2] Yao. The Present Situation and Development of China Railway Signal System [J]. Railway Communication Signal, 2003(04).
Infantry. Reliability analysis method of train control system based on communication [J]. journal of traffic and transportation engineering, 200 1(0 1).
, Chen,,. Analysis and thinking on active safety control of high-speed railway train control system [J]. Railway Computer Application, 20 12(08).
Brief introduction of the author
Sun Yifeng (1982-), male, from Tianjin. Civil aviation university of china graduated with a bachelor degree. Research direction: railway signal.
Author unit
The Third Railway Survey and Design Institute Group Co., Ltd. Tianjin 30025 1.
Click the next page for details >>& gt High-speed Railway Signal Technology Paper