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1. Project background
With the approach of the Shanghai World Expo, Shanghai has been intensively increasing the construction investment and implementation of a number of urban infrastructure including public transportation. Among the newly built three-dimensional bus parking lots, the Chengshan Road parking lot adjacent to the Expo Park will be the largest three-dimensional bus parking lot in Asia, with a capacity of 1,200 vehicles and 1,000 maintenance vehicles. The construction project includes a multi-storey parking garage, a 15-story bus office building, repair and maintenance workshops and other supporting buildings. It is a comprehensive parking lot that integrates parking, maintenance, and office functions. It is adjacent to the main Expo site and Chengshan Road. The parking lot will play an important role in the orderly distribution of a large and dense passenger flow during the Expo.
The entire project renovation and expansion includes multi-storey garages, repair garages, gas stations, washing stations, substations, operating business buildings, property management rooms, and bus office buildings. The total construction area of the 4-storey garage is about 180,000 square meters, which can accommodate The bus stops on the 5th floor and is equipped with more than 20,000 square meters of green space. The greening rate will reach about 20%. In addition, the parking lot can park more than 600 bicycles to provide convenience for citizens to connect to public transportation.
2. Project requirements
The requirements for the identification and positioning of buses in various building facilities in Shanghai’s three-dimensional bus parking area are different:
Parking building (area positioning required)
The regional positioning of the bus is carried out, and the positioning accuracy at the entrance of a parking area planned by the parking marking line is within the range of the parking area. After vehicles enter the parking building, the system is required to be able to detect in time which floor each vehicle is on, which up/down ramp, which parking area or which car repair area, and avoid detecting vehicles entering adjacent areas.
Gas station (requires matching identification)
When a vehicle enters a gas station to refuel, determine which station (a certain fuel gun of a certain fueling machine) it is refueling at, and automatically record information about the current vehicle refueling this time.
Access to auxiliary buildings and venues (requires lane recognition ability)
Point positioning of public transport vehicles, positioning accuracy to avoid detection of vehicles driving on adjacent passages, and distinguishable entry/exit at passage entrances that allow two-way driving in and out.
Field road (requires lane recognition ability)
Positioning the status of public transportation vehicles within the range of the road in the field can accurately distinguish the road they are traveling on, which can meet the needs of the roadside electronic display screen to dynamically display personalized information for oncoming vehicles and stop the information display when the vehicle leaves.
3. Project Difficulties
To count the number of existing vehicles in the parking lot, the number of vacant parking spaces (refueling stations, car wash spaces) and other information, and to realize real-time bus guidance information aggregation and transmission, it is necessary to clarify whether the bus at the entrance and exit is leaving or entering , The guidance system also needs to know which road the incoming vehicle is driving on in order to provide accurate information prompts. Accurate positioning capability is the basis of lane identification, and most common active RFID technologies do not have lane identification capabilities.
Existing RFID technology for vehicle management, for existing highway multi-channel non-stop toll collection or other occasions that require lane identification, no matter how passive RFID or active RFID identification methods are used, there is how to identify each read and write The vehicle radio frequency ID received by the device is the vehicle identification number that it should actually handle, rather than the signal sent by the adjacent lane vehicle or other trailing vehicles far away from the access control gate, which causes the problem of misreading. For this reason, in addition to using a directional antenna to limit the signal transmission direction, the lane reader also needs to limit the signal coverage to prevent signal misreading.
Compared with ordinary active tags, the identification and positioning system based on the i3RFID patented technology system of West Valley’s completely independent intellectual property rights, using 2.4GHz military direct sequence spread spectrum (DSSS) multi-channel coordination technology system, can achieve ultra-long distance While automatically identifying a large amount of distance, it meets the positioning needs of different levels and avoids the impact of interference from adjacent roads.
At this time, we don’t need to know the exact position where the electronic tag leaves each reader, nor do we care about the impact of environmental interference on the positioning accuracy, but only need to determine the channel reader that the electronic tag actually passes through. It is all possible Among the readers of each channel that receives the electronic label signal, the closest one is sufficient. According to the principle that the minimum bit error rate corresponds to the shortest distance, the recognition interference of vehicles in adjacent lanes can be eliminated.
The specific working process is as follows: The West Valley i3RFID electronic tag is usually in the default power-saving monitoring mode. At the identification position that needs to enter and exit the parking lot, the coordinator catches the moment the tag wakes up and sends a command, and the tag sends its own ID to the reader. Realize the identity recognition of the bus, and then the tag enters a deep sleep state; in the area where lane recognition is required, the coordinator sends a work mode conversion instruction, and the tag enters the positioning mode. Through the above-mentioned brand-new, economical, practical, simple and effective positioning method, The interaction between the RFID reader and the tag achieves the purpose of lane identification and ensures the accuracy and efficiency of the information management system.
Four, system implementation
The system mainly adopts West Valley i3RFID technology. Active electronic tags are installed on the parked buses, which correspond to the identity of the vehicles one-to-one. Tag readers are installed in the parking building, field passages, auxiliary buildings and main roads of the field. As a positioning benchmark for the current location (area) of the vehicle; long-distance readers are installed on the roof of the bus office building and the operating business building to provide a switch signal for the wake-up or sleep of the tag when the vehicle enters and exits the field.
West Valley i3RFID long-distance tag readers are fixedly installed at the entrances and exits of each parking area, car repair area and up/down ramps, and each vehicle entering and leaving the area is detected through the West Valley i3RFID active electronic tags;
Each refueling machine is equipped with a handheld wireless reader to collect the electronic tag information and refueling station information of the refueling vehicle, and the information is transmitted to the gas station management software to determine the current refueling vehicle and the refueling material, and provide the data to Refueling information system;
Fixedly install tag readers in each building, and detect vehicles entering and leaving the area through electronic tags.
Install tag readers at appropriate positions on both sides of the roads in the factory (building walls or lighting poles), and detect vehicles on different paths of the road through electronic tags.
5. Project results
Through the dedicated hardware and software of West Valley equipped in this project, all the public transportation vehicles in the parking lot have realized timely and accurate detection, recording and communication with regard to their vehicle identity, when and where and other information; at the same time, it is related to this project. Condition monitoring of equipment and components.
Note: The content and implementation of the project are subject to the contract. The final interpretation right of this case belongs to West Valley Company.
Appendix: Company Profile
Xi’an West Valley Micropower Data Technology Co., Ltd. is a professional IoT solution and product supplier. It has a multi-channel collaborative architecture radio frequency identification i3RFID technology system with completely independent property rights. It is a 2.4GHz active RFID national standard and 2.4G RTLS real-time positioning The drafting unit of the system’s national standards.
Xi’an Xigu Micropower Data Technology Co., Ltd.
Address: 5F, National Optoelectronics Base, No. 77, Keji 2nd Road, Xi’an High-tech Zone, China Post Code: 710075
Telephone (86-29) 8845-2611 Fax: (86-29) 8845-2610
Website: www.saycool.cn Email: [email protected]
Technical service: 400-6688-186
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