The transportation video frequency supervisory system may take the understanding transportation condition and a public security condition window, is the public security traffic guidance system essential subsystem, also is an intelligence transportation system important constituent. The establishment video frequency picture supervisory system goal is promptly accurately grasps monitors around the street intersection, the road section vehicles, pedestrian's current capacity, the transportation public security situation and so on.

Contrast tradition transportation supervisory system application superiority

1st, traditional transportation video frequency supervisory system composition

The transportation video frequency monitoring region mainly is the city main road, the key point is the traffic flow big street intersection, the road section and the accident sends the spot, all monitorings video information
All escorts to the monitoring center, this characteristic had decided the transportation video frequency monitoring network for the spot to many 点分�?network architecture, each has from the monitoring center distance nearly has far long, the distant point amounts to several kilometers to several dozens kilometers.

The traditional transportation video frequency monitoring network mostly selects the fiber optic transmission method, namely the use numeral multi-purpose light end machine transmits the video signal. The digital light end embryonic period will need to transmit the signal separately will carry on the digitization according to its respective characteristic, again will use the digital synchronization multiple connection technology (time-sharing to turn round with) merges a group high speed signal it to carry on the transmission. The digital light end machine uses the phase lock technique gain clock and aims at the phase, uses the digital algorithm to guarantee receives the start synchronization, therefore it has the quite fine reliability and the stability. The transmitting range may reach several dozens to 100 kilometers, if uses relaying to enlarge, the transmitting range may be farther.

The fiber optic transmission although has the belt spaciously, the transmitting range far, the performance steadily grades the merit, but also has the resilience in a big way, the construction cycle long, the investment is huge and so on the shortcoming. If uses rents foundation operation business the optical fiber network, then not necessarily guaranteed each may turn on immediately, also the month rents the expense quite to be often expensive, this said regarding the center small city traffic department, often incapably undertakes.

2nd, upright correspondence wide band wireless transportation video frequency supervisory system solution

Because various transportation 监控�?position quite dispersible, although lays down the optical fiber transmission system ofts effect well, but lays down the optical fiber line resources not only to be time-consuming, to take the trouble, to cost a great deal of money, moreover some times are unable to realize (for example old city, protectorate and so on do not permit trenching, wire laying, or partial places are away from very far), this time, uses the wide band wireless transmission network to become only, the economy, the effective choice. The wireless transmission merit includes:

Not region limit: The wireless transmission because uses the wireless medium, therefore may easily surmount the special obstacle, cannot to the municipal administration construction, the cultural relic historical site and so on have the influence.

Erects nimbly: To not the wired line cable limit, may increase with wishes fulfilled or redeploy the user end equipment, also may fast open the equipment transfers to the need place to reuse.

Fast implementation: The line network does not need the wiring, installs and disassembles and assembles extremely simply is all convenient, greatly saved the equipment setup time and the cost. At the same time, may use in the temporary place and so on the monitoring.

Mobility: Line network permission in any time, any place visit network, but does not have the assigned location, even also can turn on the network in the migration, the user also may seamless roam in the network.

Low use cost: Uses the wireless network, may avoid the mounted wire cable the high cost expense and rents line the month to rent the expense as well as the equipment needs frequently to move, correlation the and so on increase and change expense.

High volume of goods handled: The general wireless system has reaches as high as the 54Mbps wireless data transmission speed, far is higher than T1, the E1 line speed and the 10BaseT wired network speed.

Below each wireless correspondence frequency band (VHF/UHF/2.4GHz/3.5GHz) center, the 5.8GHz frequency band also has the superiority:

Belongs to the non- permission frequency band, does not need the frequency license;

The frequency resources is relatively sufficient, altogether 125MHz;

Technology mature, the equipment price low, the volume is small;

The frequency band is far away, the man-made noise civilly, the frequency spectrum is clean;

The transport tape is spacious, may reach 108Mbps;

Integrated equipment, installment simple, the maintenance cost is low;

Above because has the merit, the 5.8GHz wide band wireless correspondence may take the fiber optic transmission the supplement method, or as fast clears, the special land sector mainly turns on the method. Area which regarding optical fiber network and so on center small city not yet comprehensively lays down, uses the 5.8GHz wide band wireless correspondence to be allowed mainly to turn on the method as the transportation video frequency monitoring.

Chart 1 "the prestige regards passes" the wide band wireless transportation video frequency supervisory system schematic drawing

Chart 1 is the upright correspondence "the prestige regards passes" the wide band wireless transportation video frequency supervisory system whole solution schematic drawing, it other used upright correspondence SkyWay5000 5.8GHz to transmit partially to the multi- spots equipment (also may be completely) the video frequency 监控�?video frequency data, it will be at the same time many 5.8GHz the SU equipment turns on identical 5.8GHz with the point-to-point difference the AP equipment, many SU will turn on the monitoring central bureau territory network through identical AP, thus saved the equipment investment, the frequency resources and the equipment setup location and so on. Will select to multi- spots 5.8GHz the SU equipment lays aside in the front end camera position, 5.8GHz the AP equipment lays aside in the optical fiber nearby 接入�?or directly lays aside in the monitoring center place. 5.8GHz point-to-point and may unify the use to the multi- spots way, also may distinguish the independent employment.

Like the chart shows, far-end installment 摄像�? escorts to the video frequency through 75 ohms coaxial cables the video frequency encoder, the video frequency encoder the video frequency picture digitization (the MPEG-4 compression), escorts to the 5.8GHz radio equipment rep through the 10BaseT connection, then delivers through the wireless network the video frequency data in the control section local area network the video frequency monitoring server, the video frequency monitoring server Web Server which sets through in issued the picture in the network, simultaneously may carry on the video recording on the video recording server.

All may obtain the monitoring picture as necessary after the authorized users through the IE browser, and may the long-distance control 摄像�?movement, including change, the focal distance, the aperture and so on, also may according to need to carry on the local video recording. At the same time, also may in the monitoring center through the decoding connection television wall, demonstrate each 监控�?monitoring picture through the television wall.

System design principle

In order to guarantee the system the stable reliable movement, satisfies the user the use demand below, in the entire plan design and the implementation process, we will follow the principle:

Standard

This design by the profession standard took the design basis, the union transportation profession special details, manifest the highest performance price with the best design proposal compared to, is this plan design guiding ideology, also is this plan design basic starting point and the pursue goal. According to the transportation profession 监控�?distribution map, and the full consideration scene actual situation, front end designs uses the high definition colored camera, by the antijamming high shield coaxial cable transmission for the network video frequency encoder, uses the MPEG-4 compression standard, the digitized video signal will transmit through the 5.8GHz wireless network rear end monitors the computer, the guarantee video signal and the control signal accurate transmission; Also may use television wall real time display each 监控�?information.

先进�?/p>

In in the investment expenses permission situation, the system uses now the advanced technology and the equipment, on the one hand can reflect the system has advanced level, on the other hand enable the system to have the formidable development potential, in order to this system develops in the as far as possible time with the society adapts.

Reliability

The system most will be important is the reliability, the consequence which the system once will be paralysed will be imagines with difficulty, therefore the system will have reliably the continuous running. When system design accepts in the cost under the condition, from the system structure, the equipment choice, the product supplier's technical service and the service response ability and so on various aspects should strictly request, to cause the possibility which the breakdown occurs to be as far as possible few. When is appears the breakdown, affects the surface also to have to be as far as possible small.

Security

Regarding the safe guard system, its itself security performance is noticeable, when system design, must adopt the many kinds of methods to prevent this system encounters each kind of form and the way illegal destruction.

May the expansion

When system design should fully consider the next development need, the system will be supposed to have the preparation capacity the expansion with the possibility which will turn to a new generation.

Standard

Because this system is a strict comprehensive system, will refer to various aspects in the system design and the construction process the standard and the standard, strictly will comply with each technology to stipulate, will complete the system the standardized design and the construction.