Ultra-long-distance 2.4G radio frequency positioning stereo parking project case
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This case uses the patented technology of Xigu ultra-long-distance 2.4G multi-channel collaborative i3RFID, innovatively realizes precise point positioning of bus vehicles (accurate detection of lanes and driving directions) through microwave systems, matching and identification of refueling stations and massive three-dimensional parking lots. The bus ID reading realizes timely and accurate detection, recording and communication of information such as vehicle identity, when and where, and combines the information management system to instantly update the data and provide user feedback. The three-dimensional bus parking lot can park 1,200 vehicles and maintain 1,000 vehicles. The construction projects include multi-storey parking garage, 15-storey bus office building, repair and maintenance workshop and other supporting buildings.
1. Project Background
With the approaching of the Shanghai World Expo, Shanghai has increased investment and implementation of a number of urban infrastructures including public transportation. Among the new three-dimensional bus parking lots, the Chengshan Road Parking Lot adjacent to the Expo site will be the largest three-dimensional bus parking lot in Asia, which can park 1,200 vehicles and maintain 1,000 vehicles. The construction project includes multi-storey parking garage, 15-story public transportation office building, repair and maintenance workshop and other supporting buildings. It is a comprehensive parking lot integrating parking, maintenance, office and other functions. Because it is adjacent to the main venue of the World Expo, Chengshan Road The parking lot will play an important role in the orderly distribution and distribution of the large and dense passenger flow during the Expo.
The reconstruction and expansion of the whole project includes multi-storey garage, repair garage, gas station, washing station, substation, operation business building, property management room and bus office building, etc. 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, and the greening rate will reach about 20%. In addition, more than 600 bicycles can be parked in the parking lot, providing convenience for citizens to connect to public transportation.
2. Project requirements
The requirements for the identification and positioning of public transport vary among buildings and facilities in the Shanghai three-dimensional bus parking lot area:
Parking building (requires regional positioning): Perform regional positioning of bus vehicles, and the positioning accuracy at the entrance of a parking area planned by the parking space marking is within the scope of the parking area. After the vehicle enters the parking lot, the system is required to be able to detect in time which floor, which up/down ramp, which parking area or which repair area each vehicle is on, while avoiding the detection of vehicles entering adjacent areas.
Gas station (requires matching identification): When the vehicle enters the gas station to refuel, determine which station (a fuel gun of a fuel dispenser) it is refueling, and automatically record the current vehicle’s refueling information.
Entrance and exit of ancillary buildings and field areas (lane identification capability is required): Point positioning of bus vehicles, positioning accuracy to avoid the detection of vehicles driving on adjacent passages, and distinguish the entry/exit at the passageway that allows two-way driving. allow.
Field roads (lane identification capability is required): within the range of the driving roads in the field, the state positioning of the bus vehicles can accurately distinguish the road they are traveling on, which can meet the requirements of the roadside electronic display screen to dynamically display personalized information for the incoming vehicles , and stop the message display when the vehicle leaves.
3. Project Difficulties
In order 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 at the same time to realize the summary and transmission of real-time bus guidance information, it is necessary to clarify whether the bus at the entrance or exit is driving out or in. , the guidance system also needs to know which road the oncoming car is driving on, in order to provide accurate information prompts. Precise positioning capability is the basis of lane identification, while most common active RFID technologies do not have lane identification capability.
Existing RFID technology for vehicle management, for existing highway multi-channel non-stop tolls or other occasions that require lane identification, regardless of whether passive RFID or active RFID identification methods are used, there is a way to identify each read and write. The radio frequency ID of the vehicle received by the device is the vehicle identification number it should actually process, not the signal sent by the vehicle in the adjacent lane or other trailing vehicles far away from the access control gate, thus causing the problem of misreading. To this end, in addition to using directional antennas to limit the direction of signal transmission, lane readers also need to limit signal coverage to prevent signal misreading.
Compared with ordinary active tags, the identification and positioning system based on the i3RFID patent technology system of Xigu completely independent intellectual property, using 2.4GHz military direct sequence spread spectrum (DSSS) multi-channel collaborative technology system, can achieve ultra-long distance. While automatically and massively identifying distances, it can meet different levels of positioning needs and avoid the impact of interference from adjacent roads.
At this time, we do not need to know the exact position of the electronic tag leaving 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, which is all possible Among the various channel readers that receive the electronic tag signal, the closest one is enough. According to the principle that the minimum bit error rate corresponds to the shortest distance, the identification interference of vehicles in adjacent lanes can be eliminated.
The specific working process is as follows: Xigu i3RFID electronic tags are usually in the default power-saving monitoring work mode. In the identification position that needs to enter and exit the parking lot, the coordinator seizes the moment when the tag wakes up and sends a command, and the tag sends its own ID to the reader. The identification of the bus is realized, and then the tag enters a deep sleep state; in the area where lane identification is required, the coordinator sends a working mode switching instruction, and the tag enters the positioning mode. 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.
4. System implementation
The system mainly adopts Xigu i3RFID technology, and installs active electronic tags on the on-site bus vehicles, which correspond to the vehicle identities one-to-one. As a positioning benchmark for the current location (area) of the vehicle; install a long-distance reader on the roof of the bus office building and operation business building to provide a switch signal for the wake-up or sleep of the tag when the vehicle enters and leaves the field.
The West Valley i3RFID remote tag reader/writer is fixedly installed at the entrance and exit of each parking area, repair area and up/down ramp, and each vehicle entering and leaving the area is detected through the West Valley i3RFID active electronic tag;
Each refueling machine is equipped with a handheld wireless reader to collect the electronic tag information and refueling station information of the refueling vehicle. refueling information system;
Fixed installation of tag reader/writer in each building to detect vehicles entering and leaving the area through electronic tags.
Install tag readers at appropriate positions on both sides of each driving road in the factory (building walls or lighting poles), and detect vehicles on different paths of the road through electronic tags.
5. Project achievements
Through the West Valley special hardware and software equipped in this project, timely and accurate detection, recording and communication are realized for all the bus vehicles in the parking lot regarding their vehicle identities, when and where they are, etc. Condition monitoring of equipment and components.
Xi’an Xigu Micropower Data Technology Co., Ltd. is a professional Internet of Things solution and product supplier. It has a multi-channel collaborative architecture radio frequency identification i3RFID technology system with completely independent property rights, which is a 2.4GHz active RFID national standard and 2.4G RTLS real-time positioning. The drafting unit of the national standard of the system.
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