5km distance wifi module wharf/highway construction wireless monitoring transmission, the project is located in Taizhou ferry wharf, 1.6 kilometers away. It is required to transmit the surveillance on the two ferries and the front-end terminal to the terminal surveillance center. The first 13 channel images, 12 channel images for each ferry, ferry speed about 15km/h.
After a field investigation by technicians of wifi module at a distance of 5km, it was found that there were many wireless Bridges and walkie-talkies near the dock, and the microwave interference of the same frequency was serious. In order to deal with the problem of microwave interference in the environment, our company decided to use CV5200 module, which has strong anti-interference ability, while increasing the radio frequency signal transmission power, enough to resist the surrounding microwave interference at the same frequency.
Since the wireless network bridge could not align with the receiving end during the ferry's U-turn, technicians on site decided to use three 19dbi120° Angle antennas to form a 360° comprehensive signal transmission to fully cover the navigation route of the ferry, and a 5km distance wifi module to ensure that the signal of the surveillance camera on the ferry was stably transmitted back to the monitoring center during the voyage.
In addition, crews on ferry ships also use radio walkie-talkies, which can also interfere with the microwave signal of the wireless bridge. In order to solve this problem, the technicians of our company changed the position of the wireless bridge antenna and increased the height of the wireless antenna bracket to avoid interference from the microwave signal of the walkie-talkie.
When all the preparatory measures are completed, the 5km distance wifi module wireless video monitoring system will be put into use immediately. After several ferries sailing back and forth, the Jiaojiang Wharf monitoring Center can also watch a total of 25 high-definition surveillance videos of the two ferries and the front wharf in real time. The whole process is stable and without bad conditions.
A successful case of wireless video monitoring at the construction site of 104km wifi module highway at a distance of 5km, and difficulties in highway construction monitoring and construction. Highway construction in hilly and plateau areas is generally far away from existing roads, bridge height, tunnel length, steep slope, large amount of excavation and filling works, extremely inconvenient traffic, poor construction conditions, and far away from the network arranged by telecom operators. Some project managers want to set up a monitoring information system, but they have to give up due to difficulties such as high cost, long construction cycle and difficult follow-up maintenance.
The headquarters plans to build a monitoring system for green expressways and high-quality expressways from the perspectives of environmental protection, quality and construction period. To monitor the water quality of Lufeng Shaoqing Reservoir and Yimen Meizen Reservoir, and to timely and on-line monitor, analyze and evaluate the impact of construction on water quality; Construction of atmospheric environment monitoring system in Anfeng Interchange hub to monitor the impact of construction on atmospheric environment; Build video surveillance at interchange junction, Qinfeng Interchange junction, Yimen Interchange junction and other nodes to assist in effective management of construction safety, quality and progress.
Wuyi high-speed monitoring system includes three subsystems: video monitoring, atmospheric environment monitoring and water quality monitoring. The system includes 2 water quality monitoring points, 3 atmospheric environment monitoring points and 9 video monitoring points:
Point position
monitoring
1
Interchange junction monitoring point
video
2
Yingda Bridge monitoring point 1
video
3
Yingda Bridge monitoring point 2
video
4
Shaoqing reservoir
Water quality and video
5
Interchange hub monitoring point 1
Video surveillance
6
Anfeng Interchange hub monitoring point 2
Video surveillance
7
Interchange hub monitoring point 3
Video surveillance
8
Operating environmental monitoring site 1
Air quality monitoring
9
Operating environmental monitoring site 2
Air quality monitoring
10
Operating environmental monitoring site 3
Air quality monitoring
11
Bridge monitoring point
Video surveillance
12
Meizen reservoir
Water quality, video surveillance
Highway monitoring site
It can be seen that the monitoring points of this project are scattered, the network coverage is large, and it is located in hilly areas, making it difficult to construct. In fact, the core of the proposed Wuyi high-speed monitoring system is monitoring, and the difficulty lies in information transmission.
If the Internet network is used, the front end is scattered and far away from the public network. Therefore, not only the initial construction cost is high, but also the subsequent traffic cost is high. In the application of fixed IP, the cost is higher. If 4G transmission is adopted, although the amount of network construction is small, the subsequent traffic cost is not small.
In order to solve the problem of information transmission, after a lot of investigation and demonstration, the wireless LAN is constructed by using the wireless directional transmission scheme of wifi module at a distance of 5km, and the information data of water quality monitoring, air monitoring and video monitoring subsystems are integrated to realize the multi-purpose of one network.
In previous cases of wireless directional transmission, it is all line-of-sight transmission, so in this project, at least 15 relay points should be set as usual. This not only causes high cost, but also consumes a large amount of network bandwidth after multiple relay hops, resulting in poor transmission performance.
Various difficulties put forward high requirements for the wireless directional equipment to be used in this project. After many investigations, the layered construction and integrated network mode is adopted. The front end adopts 100MB 5km distance wifi module to ensure transmission and reduce construction costs; The main link adopts industrial gigabit wireless base station, which supports high-gain microwave antenna to ensure smooth transmission of data information after integration.
Various difficulties also put forward high requirements for the selection of relay points in this project. There should not be too many relay points to ensure that the cost is within the budget range. The wireless LAN bandwidth of the wifi module at a distance of 5km is sufficient to transmit monitoring information and data, and ensure that the link can be connected smoothly over long distances. This is a huge technical risk, the microwaves are likely to be covered by mountains on the front line, the front relay point will not be able to receive the data signal, causing link congestion.
Definite point position
After field investigation and point collection by technicians, the location of each monitoring area is determined by combining road direction map, zonal topographic map, field measurement coordinates and Google Digital Earth. The relay point of wifi module with a distance of 5km is selected as high altitude, large road or agricultural road as possible, so as to facilitate equipment transportation and installation. For wireless transmission, the points must be selected to ensure that the middle of the points is visible.
Description of relay points:
Relay station
description
Trunk 1#
Southwest of the hub area, general agricultural driveway
Trunk 2#
Close to the wind power tower of the horse washing farm, through the road, about 10KMM away from the trunk 1#
Trunk 3#
The mountain top on the west side of Yingda Bridge is connected with the agricultural driveway, about 11 kilometers away from Zu2 #
Trunk 4#
It is estimated that the northeast peak is more than 1 km away from the agricultural road, about 8 km away from Zuizui 3#, about 6 km away from Zuizui 5#, and about 10 km away from Zhongji 5#
Anfengying
Trunk 4# is about 10 km
headquarters
Trunk 5# is about 9 km
Trunk 5#
Fengying south to the west, through the big car road, 12 kilometers away from the headquarters
Trunk 9#
Fengying south to the west, through the big car road, about 7 kilometers away from Trunk 5, trunk 6 to Trunk 9, trunk 9 to trunk 5
Trunk 6#
At the top of the hill on the northwest side of Crab Qing, it is about 400 meters away from the agricultural driveway and about 10 kilometers away from the trunk 9#
Trunk 7#
At the top of Xiagongjiaying Hill, it is about 200 meters away from the agricultural driveway and about 7 kilometers away from Zou6 #
Trunk 8#
East side of Meizen Reservoir, about 8 km from Trunk 6#
Design transmission scheme
According to the site requirements and points, a wifi module with a distance of 5km is selected to establish a central backbone transmission link. Single-mode devices are used for integrated transmission at the front end, and dual-mode devices are used for relay transmission at the relay points. Data collected at the front end monitoring points and environmental detection devices are transmitted back to the monitoring center through the 100-megabit wireless module.
