Technology and safety control and management control of large-scale sports events (2)

3 Satellite Global Positioning System (GPS) application system structure and function
As a large-scale event, the flow of traffic and the communication of large arteries, there are many and scattered races in the competition, and even the comprehensive large-scale sports in many surrounding cities will play an important role. With the development of society, the changes of the sports meeting itself and the external environment, more stringent requirements are imposed on the efficient and safe handling of the management and control of the meeting vehicles. The traditional methods of relying entirely on human subjective consciousness and experience are already incapable, and must rely heavily on advanced scientific and technological means. The use of GPS in the AVL-Automatic Vehi-cle Location for public transportation, public security inspections, long-haul freight, financial and criminal escorts is an excellent example.
The GPS Global Positioning System is a satellite-based radio navigation system that was deployed by the US Department of Defense in the 1990s to meet military needs. While performing the Military Precision Positioning Service (PPS), it also unconditionally opens and provides the Civil Standard Positioning Service (SPS), which provides all-day, all-weather, high-precision for the global land, sea, air and military civilian objects. 3D space, speed and time information. In order to compete with the United States and avoid being constrained by political and military factors, other countries, regions and organizations around the world have also established their own satellite navigation systems, such as GLONASS (GLObal NAvigation Satellite Sys-tem) completed in Russia in 1996. This article uses GPS as an example, but its principles and methods also apply to the latter.
The characteristics of conference traffic management for large-scale sports events are: the number of vehicles is large, the types of vehicles and services, the scope of the jurisdiction, and the sources of vehicles and drivers are quite complicated. The scientific and reasonable flexibility of scheduling, the timeliness and accuracy of arrival time, the safety and reliability of running parking, and even the screening control, tracking and inquiries, and emergency response of personnel and vehicles have strict requirements. As a result, the use of GPS in this field has many unique features that are different from other fields. In view of the identification of the occupants and the tracking and query requirements have exceeded the scope of GPS functions, this paper proposes a vehicle and personnel automatic positioning and tracking scheme that combines GPS and ICC technologies.
3.1 System Structure
In general, GPS is mainly composed of three parts: space satellite, ground control part and user equipment.
The first two parts are controlled by the US military and provide services free of charge. The main research and work content when users build GPS application systems are limited to user equipment. The basic components of this part are GPS receivers (with antennas with built-in preamplifiers, transmission cables and receiving hosts). For other application purposes and occasions, additional facilities, such as the system shown in Figure 2 of this article, should at least include:
3.1.1 Accusation Center
The basic structure of the Conference Traffic Command and Control Center (referred to as the Accusation Center) for tracking and dispatching all vehicles and personnel is: large-screen electronic display, computer network system, database system, geographic information system, etc. among them:
(a) The computer network system is the operation platform for dispatching and commanding. In addition to the related resources of the center, it is also involved in the traffic management sub-terminals of the sub-meetings and related functional departments connected by wired media. These sub-terminals can be independent dedicated devices or a functional option of the relevant department's integrated information management system platform.
(b) Large-screen electronic display for final output of digital and image information, is an important human-machine interface for dispatching command, and has a variety of options. This program takes a high-lumen rear-projection or front-projection projector that is relatively inexpensive and suitable for indoor use.
(c) The database system stores various information related to traffic command and dispatch, including: source information of the conference vehicle (model, car number, color, vehicle condition, age, source, conference use and number, etc.), driver source information (name, Gender, age, driving age, source, violation and accident record, etc., current and past data for each vehicle or each driver's service (including time, task, corresponding driver or vehicle, route, number of passengers / nature / index identification code) And more detailed information, emergency content / time / location and solutions, as well as scheduling and processes, blacklist changes and investigation records ... and so on.
(d) GIS-Geo-graphical Information System is used to graphically and intuitively describe the current position, direction of travel, movement trajectory, etc. of the object being tracked to the central controller on the electronic map of the large-screen display. To provide a sufficiently accurate basis for its scientific and efficient command and dispatch decision-making. Its digital map, the map database, is the source of information for large-screen electronic maps. The accurate integrity and information volume of the library will directly affect the GIS performance and positioning accuracy. The library can be used to scan paper city block maps or geographical aerial images by scanning scanners, and store and retrieve them in raster coding structure (the advantage is that it is in good agreement with the actual map, and it is convenient and quick to set up. However, the memory is large and used. Limitations, only part of the application of the accusation center with sufficient resources; can also use the digitizer to generate node coordinates from the above source data point by point, and finally form a virtual road data network - vector coded map (the advantage is memory occupancy Less, faster access, flexible and convenient application, truly reflecting the geometric parameters and topological structure of each road element; but the establishment process is tedious and lengthy. When conditions permit, the results of the survey department can be used, but it must pay attention to the high-speed changes of urban construction. The effect of timeliness), the latter is used in this scheme.
The map matching (MM-Map Matching) technology used in the system can compare the vehicle motion route feature information sent by each in-vehicle device with the road feature of the digitized map to correct the movement of the vehicle on the electronic map when the satellite visibility is extremely poor. The trajectory further reduces the influence of the vehicle driving environment on the positioning accuracy.
3.1.2 Data Link
The information is used to transmit the position, speed, time information and alarm information obtained by the on-board GPS receiver to the satellite GPS signal, and to the center for the voice dispatching command of each vehicle. The wireless communication system covers the related communication facilities of the in-vehicle wireless communication device and the accusation center.
Cellular phones, communication satellites, cluster systems, and other short-wave or ultra-short-wave communications can be used for this data link, but the performance characteristics are different. For example, satellite communications have large coverage beyond any other way, but the antenna size is large and the equipment is heavy. The cost is high; the coverage of the GSM cellular phone is relatively large, and the short message service (SMS-Short Message Service) data transmission can be conveniently used when infrequently located, but the cost is high when the frequency is tracked and the queue is blocked when the channel is crowded. Shared cluster system can reduce user costs, avoid communication waiting, but the coverage is small... and so on. User selection should be based on: data throughput, transmission rate, coverage, implementation and operating costs.
In view of the operating costs and the large number of cities hosting large-scale events, there are already dedicated cluster mobile communication facilities for other fields. This program proposes to rent such off-the-shelf equipment (for example, the relevant ministries and commissions in Beijing and relevant departments in Beijing have so far had more than 10 simulations. The cluster communication network has more than 10,000 users. It is planned to build an advanced digital trunking communication shared command and dispatch network in 2005, which will have a capacity of 100,000 users and cover all districts and counties in Beijing. In the full use of the original functions of these devices, while carrying out a variety of voice scheduling command and communication, through the corresponding configuration, the rapid transmission of relevant information. That is: active immediate transmission of alarm and card information, active timing transmission of positioning information or passive response transmission (the latter is used for long-term parking of vehicles, etc. In this communication mode, the vehicle-mounted device only acquires the central command via the wireless channel. Send location information to further reduce channel occupancy).
3.1.3 Differential Station
In order to reduce the system error caused by satellite clock error, ephemeris error, atmospheric transmission delay error, and the influence of man-made interference imposed by SA-Selective Availability (US) for positioning accuracy Differential GPS (DGPS-Differential GPS) technology should be used to establish a differential station in the accusation center. The differential station uses the known precise position coordinates and the GPS reference receiver to measure the difference between the solved coordinates to obtain the pseudorange correction number.
In view of the fact that the implementation goal of the program is to track and track only by the accusation center, and the mobile vehicle does not display any positioning information (ie, establish a pure centrally controlled AVL system), the correction data is not broadcasted, but the center uses the data for each The vehicle sends the information separately for correction processing, then displays the storage, and separately transmits the corresponding sub-site or functional department traffic management sub-terminal. The concentrated difference-backward pseudorange difference is beneficial to improve system efficiency and reliability and reduce channel occupation; however, it requires high capital, technology and workload for the center.
In some non-navigation applications where positioning accuracy is not high, in order to save money, there is also no successful use of DGPS, but more relying on dynamic filtering theory and methods to improve positioning accuracy.
3.1.4 DR device
High-rise buildings, tunnels, shades, interchanges, etc. may affect the normal reception of satellite signals, resulting in GPS positioning accuracy degradation or even failure, forming a tracking blind zone. To this end, a DR-Dead Reckoning device consisting of a moderately accurate and inexpensive piezoelectric crystal rate gyro and an odometer is added to each positioning vehicle to form a GPS/DR combined positioning system together with GPS. When the GPS satellite signal is occluded, the DR positioning function is enabled, using its good short-term accuracy, eliminating the tracking blind zone and ensuring the positioning continuity; when there is no occlusion, it is positioned by GPS, and assists in correcting the DR device to avoid gyro drift. The cumulative error of DR.
It should be pointed out that in the case of satellite visibility is very poor (satellite signals are blocked for a long time, such as commercial buildings, boulevards, etc.), the gradual increase of gyroscope azimuth accumulation error will significantly increase the DR estimation error. The GPS/DR combination positioning output error of the in-vehicle device is also significantly increased. This error can be corrected by the map matching (MM) method, which is corrected by the accusation center based on the road attributes of the digital map and the vehicle trajectory.
The range of possible accuracy when different positioning schemes are indicated. Obviously, the improvement in positioning accuracy is usually at the expense of technical and system complexity and increased investment.
3.1.5 Alarm button
The vehicle-mounted machine is equipped with a plurality of buttons (keys), which respectively correspond to fault breakdown, traffic accidents, road congestion, violent grievances, etc. (there are multiple violent lyric buttons, respectively, and different parts of the vehicle are placed/hidden). Pressing the same button twice in a short time, the on-board machine sends the corresponding alarm message, and the accusation center monitors the large screen to immediately display the alarm object position, car number, alarm type, and supplemented with the corresponding sound and light reminder.
3.1.6 Card Reader
GPS can only locate and track the vehicle, while the access of the ICC reader can identify and record the identity of the driver and passenger. Then, through the same data link, the card number and credit card time of the card held by the driver and the passenger will be sent to the accusation center for further inspection and tracking.
The card reader is similar to the contactless card reader of the bus IC card system. In order to enable the accusation center to keep abreast of the changes in the car, all drivers and passengers need to swipe the card to get on and off. The on-board machine is specially equipped with a button (key) type switch and an acousto-optic indicating device, and the state of the switch and the light indicator respectively correspond to the boarding and getting off of the card holder. When the card is swiped, the card reader automatically generates a "please get on the car" and "please get off" voice prompts. The up or down status information will be saved with the card number, card time, etc. (card reader) and sent. The card reader will reject and sound a warning for any card that is stuck in the same state of the same vehicle.
If necessary, the IC card can also be transferred via the aforementioned wireless data link or dedicated data to download the "Allow Bus Number" to the card reader. The card reader will refuse to allow the non-permitted person to swipe the card accordingly, and the voice prompts.
3.2 Main functions
The main functions of the system can be summarized as:
3.2.1 Vehicle tracking
The in-vehicle device periodically sends its own current position, speed, time and other information, accusing the center of receiving and recording the archive, while displaying the operation status in real time on the electronic map of the surveillance large screen in the form of point coordinates or continuous movement track.
On the big screen, vehicles of different mission types (ambulance, police, material transportation, delegation pick-up, etc.) can be marked in different colors. It can display all conference vehicles or only one type of vehicle. It can display related conference vehicles in the whole city or a certain area or even a certain street, and can also track the display part or even a certain vehicle. You can choose to display the vehicle number, model, function, location and street. You can zoom in, zoom out, and select to switch. Multiple windows can be displayed in multiple windows or multiple windows to track multiple vehicles.
Of course, the above screen display work can also be completed by multiple display terminals of the network system. The traffic management sub-terminals that are respectively attached to each sub-site or functional department can share the graphic and text information associated with the center.
3.2.2 Personnel tracking
Both the driver and the passengers are swiped in and out of the vehicle. The card number of the driver and the card holder are immediately sent to the accusation center archive together with the card swiping time and the status of the boarding and disembarking. When necessary, the center can use the card number as an index to retrieve personal information such as the name, age, gender, country (province), identity, and project of the relevant personnel from the ICC system database. According to this, the center can not only know how many people have or have been on a certain car, who is or who they used to be, and when they get on/off, they can also inquire about a delegation or an identity, a project person or even someone. Which / car is currently or ever. The current position, movement track and related text information can be tracked and displayed in real time on the electronic large screen or other display terminals of the network.
3.2.3 Alarm Processing
The in-vehicle device sends all alarm messages immediately. The center urgently responded to such alarms, especially traffic accidents and violent grievances. At the same time as the sound and light prompts, the current position was flashed on the electronic large screen or other display terminals, and the text showed the location of the incident and even the vehicles and personnel. information. The location of the hospital, security patrol vehicle or department near the incident location can be automatically displayed on the electronic map for the commander to make reference. At the same time, the voice call of the center, the alarm vehicle and the emergency response department will be connected as soon as possible to carry out command and rescue.
3.2.4 Late inquiry
In addition to real-time tracking, the accusation center can also search for traffic conditions of a certain time period, a certain road section, a certain vehicle, a certain group, or a certain person. In addition to images (trajectory playback, etc.) or text display on the screen, printouts can be printed for further statistical analysis.
3.2.5 Command and dispatch
The voice communication function of the in-vehicle device greatly facilitates the command and dispatch of the conference traffic, and the real-time and accurate acquisition of the information of the conference vehicles and personnel positions, time and alarms by means of GPS and ICC technology further lays the scientific orderly and efficient and reasonable arrangement of the command and command. basis. It not only facilitates the timely and accurate arrival and evacuation of personnel and materials, but also facilitates the management of complex vehicles and personnel from sources, and the handling of various emergencies, such as route guidance when roads are blocked, and repairs and replacements during breakdown of faults. It is especially valuable for remedies, emergency ambulances during traffic accidents, and defense and rescue during violent grievances.
4 Conclusion
The GPS positioning and tracking system using the satellite as the information source and using the wireless channel as the data link between the in-vehicle device and the accusation center can be regarded as a "Skynet" system; basically, the wired medium is used to realize the inter-card terminal and the system. The ICC application system for information transmission is a "ground network" system. The organic integration of the two systems will cover all areas of the conference and become an indispensable eye, touch and arm of the integrated large-scale sports information management system. In this way, the organizers of the conference can not only fully grasp the running status of the entire conference personnel and vehicles, but also quickly find out the location and movement trajectory of the personnel or the current or any time period of the vehicle at the venue. It not only helps efficient and orderly scientific management, decision-making, but also has more value and meaning that cannot be ignored in security defense.
The ICC timing in the Atlanta Summer Olympics and other international marathons, and the GPS positioning in the security of the Salt Lake City Winter Olympics are all successful attempts and applications. It is believed that with the further development of technology, with the dramatic changes in the complicated international situation and the deepening of people's understanding, GPS and ICC technologies will definitely play a role in large-scale comprehensive sports games, especially the world-renowned Olympic Games. Great effect!

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