Application scheme of GPRS environmental protection data collection system

As the technical department of the national environmental protection system, the environmental monitoring department is an important foundation for environmental management. With the enhancement of citizens' environmental awareness, more and more people have begun to care about the quality of the environment they live in, and require transparency in environmental protection work; higher-level competent departments also need information with a large quantity, variety and fast update. All of this raises a question that should be paid attention to for the environmental monitoring department: how to establish an environmental protection data collection system with strong practicability, wide coverage and good flexibility to meet the needs of all parties for environmental monitoring information.

In the environmental protection system, it is often necessary to monitor many pollution discharge points in real time, and most of the monitoring data needs to be sent to the back-end server of the management center in real time for processing. Due to the dispersion of monitoring points, wide distribution, and most of them are set in areas with harsh environments, transmitting data through telephone lines is often twice the result with half the effort. Data transmission through the GPRS wireless network has become one of the communication methods chosen by the environmental protection department. Pollution source monitoring equipment can send the collected pollution data and alarm information to the environmental protection monitoring department in time through the GPRS network, so as to realize the timely management of pollutant discharge units or individuals, which can greatly improve the work efficiency of the environmental protection department.

1. Project requirements

A province now has 16 urban environmental monitoring stations and monitoring stations in counties and districts included in the provincial monitoring network. There are 102 environmental monitoring stations above the third level. The main objects of monitoring are the discharge and treatment of industrial "three wastes" and the atmospheric environment., water environment, noise environment, etc. Including: monitoring the current status of air environment quality in 14 cities, the water quality status of 12 major water systems, 7 major lakes and reservoirs, 7 near-shore harbors and drinking water sources in 16 cities, the current status of noise pollution in 9 cities, and through comprehensive indices and other methods. Trend analysis, and finally draw environmental quality conclusions.

The provincial environmental protection data collection system is a pollution source monitoring system composed of pollution source discharge monitoring points and monitoring centers. The system can automatically sample pollution sources and conduct online monitoring of major pollution factors; grasp the urban pollution source discharge situation and total pollution source discharge, and automatically transmit the monitoring data to the provincial environmental protection monitoring center; the computer of the monitoring center will summarize, organize and comprehensively analyze the data; The monitoring information is transmitted to the Provincial Environmental Protection Bureau, and the Provincial Environmental Protection Bureau supervises and manages the pollution sources.

At present, pollution source monitors are installed at each pollution source discharge monitoring point to monitor pollution sources. The monitoring center receives the monitoring information transmitted by the monitoring points; and is responsible for classifying, screening and comprehensively analyzing the monitoring information. As the decision-making center of the system, the Provincial Environmental Protection Bureau analyzes and investigates the monitoring information obtained from the monitoring center station, makes management decisions in a timely manner, and increases management efforts.

At present, the data communication between the provincial environmental protection monitoring station and each collection point is mainly transmitted by manual transcription or PSTN telephone line. When using telephone lines to transmit data, due to the need to wait for each dial, the speed is slow and the cost is high. At the same time, due to the wide distribution, large number and long distance of each monitoring point, and individual points are still located in remote areas, many telephone lines need to be applied for, and some monitoring points are difficult to reach by wired lines.

GPRS has the characteristics of fast speed and low cost of use, and its transmission speed can reach 171.2kb/s. Compared with the wired communication method, the GPRS wireless communication method is very flexible. It has the advantages of flexible networking, easy expansion, low operating cost, simple maintenance and high cost performance. Therefore, the GPRS wireless transmission method is currently being considered to solve the problem of pollution source monitoring data. Real-time transmission problem.

2. Program advantages

China Mobile GPRS system can provide wide-area wireless IP connection. Building an environmental protection information collection and transmission system on the GPRS service platform of the mobile communication company to realize the wireless data transmission of environmental protection information collection points has the advantages of making full use of the existing network, shortening the construction period, and reducing the construction cost, and the equipment is easy to install and maintain. Simple. After comparative analysis, we choose China Mobile's GPRS system as the data communication platform of the environmental protection information collection and transmission system.

GPRS wireless environmental pollution source online monitoring system has the following characteristics:

1. Strong real-time performance: Compared with short message service, because GPRS has real-time online characteristics, the system has no delay, and can receive and process various data of multiple/all monitoring points synchronously without wheel patrol. It can well meet the real-time requirements of the system for data collection and transmission.

2. Remote control of instruments and equipment at each monitoring point: reverse control of instruments and equipment can also be realized through the GPRS two-way system, such as time correction, status report, switch and other control functions, and remote online upgrade of the system can be carried out.

3. Low construction cost: Due to the use of the GPRS public network platform, there is no need to build a network, just install the equipment, and the construction cost is low;

4. Wide monitoring range: The construction of an environmental protection information collection and transmission system requires a wide coverage of data communication, unlimited expansion, and unlimited access locations, which can meet the access needs of mountainous areas, townships and cross-regions. Due to the large number of environmental protection information collection points, which are distributed throughout the province, some environmental protection information collection points are located in remote areas and are geographically dispersed.

5. Good scalability: Since the current GSM/GPRS network has covered most areas in the province, there is basically no blind spot, which can realize a wide range of online monitoring and meet the coverage requirements of the environmental protection information collection and transmission system.

6. The transmission capacity of the system is large: the environmental protection center station should be connected in real time with each environmental protection information collection point. Due to the large number of environmental protection information collection points, the system requirements can meet the needs of sudden data transmission, and GPRS technology can well meet the needs of sudden data transmission.

7. High data transmission rate: The data transmission volume of each environmental protection information collection point is within 10Kbps. The GPRS network transmission rate can theoretically reach 171.2kbit/s. At present, the actual data transmission rate of GPRS is about 40Kbps, which can fully meet the requirements of the system's data transmission rate (≥ 10Kbps).

8. Low communication cost: Monthly Flat method is adopted, and the operating cost is low.

3. Solution introduction

Since the GPRS communication is a data packet communication network based on the Internet Protocol Address, the host computer of the monitoring center has a fixed Internet Protocol Address configuration, and each data collection point uses the GPRS module to communicate with the host.

1. Environmental protection information collection points:

The on-site monitoring point automatically collects pollution source information through the data collection module, and is connected to the GPRS transparent data transmission end point through the RS232 interface. The built-in embedded processor of the GPRS transparent data transmission end point processes the data and sends it to the GSM network after protocol encapsulation.

2. Monitoring Center:

The server applies for the configuration of a fixed Internet Protocol Address, adopts the DDN dedicated line provided by the provincial mobile communication company, and is connected to the GPRS network. Since the DDN dedicated line can provide higher bandwidth, when the number of environmental protection information collection points increases, the center can meet the demand without expansion. After receiving the data from the GPRS network, the RADIUS server of the monitoring center first performs AAA authentication, and then transmits it to the computer host of the monitoring center. The data is restored and displayed through the system software, and the data is processed.

3. GPRS/GSM mobile data transmission network:

The data collected by the on-site monitoring point is simultaneously decoded by the GSM network air interface function module, converted into the format of data transmission on the public network, transmitted through China Mobile's GPRS wireless data network, and finally transmitted to the Internet Protocol Address of the monitoring center.

(2) SYSTEM PLAN

Each monitoring point uses the GPRS transparent data transmission end point and is connected to the monitoring center through the mobile GPRS network. Each pollution source data collection point uses the unified STK card of the mobile communication company. At the same time, the monitoring center registers each point and saves relevant data for identification and maintenance. Each information collection point runs the monitoring system software, supports 24-hour real-time online, and realizes the 24-hour transmission of collected environmental protection information and data by the information collection point.

All information collection points authorized by the Provincial Environmental Protection Bureau can use this system:

1. The environmental protection information collection point must use a mobile unified STK card, and the user can only use this card for data communication with the environmental protection station.

2. The end point equipment uses the GPRS mobile data communication end point (JY-RTU4100 or JY-RTU6640) provided by Beijing Juying Soaring Electronics Co., Ltd.

3. User registration: in line with the regulations of the provincial environmental protection bureau.

(3) Product characteristics

1. Provide equipment status indicators to facilitate equipment maintenance;

2. Wide voltage supply range: 5V-30V;

3. With RS232, RS485;

4. Built-in large-capacity SPI-flash (capacity optional 1Mbit-64Mbit), to achieve long-term local storage of data (need to be customized);

5.4 analog input, acquisition accuracy: 12bit

6. Transmission supports a variety of protocols, our company's custom protocols and Modbus protocols (ASCII, RTU, Modbus TCP) are perfectly supported;

7. The data transmission adopts the GSM module to realize the functions:

1) GPRS disconnection automatic reconnection;

2) Up to 6 central servers can be connected at the same time as needed;

3) Support fixed IP, domain name resolution and APN private network addressing;

4) Support TCP, UDP, PPP, ICMP, DNS, FTP and other protocols;

5) The number of nodes supported is theoretically unlimited as long as the server resources allow;

6) Reduce the cost of wiring and the trouble of construction;

7) Support SMS data transmission, SMS parameter configuration function;

8) Support phone and SMS wake-up function;

8. Support special software for local and remote parameter configuration and maintenance;

9. Support local and remote firmware upgrades;

(4) Safety measures

Due to the particularity of the environmental protection data collection system, this system requires extremely high system security and stability. Security is mainly to prevent intentional and unintentional damage from inside and outside the system. Cyber security protection measures include channel encryption, source encryption, login protection, access protection, access protection, firewall, etc. Stability means that the system can run 7 × 24 hours without interruption, even if hardware and software glitch occurs, the system cannot be interrupted. DataPlatform can use VPN to access the mobile GPRS network through the public network. The cost of using VPN is relatively low. Enterprises do not need to rent a dedicated line, and can also use the original VPN equipment. Mobile end points need to install the function of VPN secondary virtual dialing. software. Through VPN, the client side must be authenticated by the Radius server before connecting to the application server. The entire data transmission process has been encrypted and protected, and the security is relatively high, which can fully guarantee the speed and network service quality. In addition, DataPlatform can also use the APN access method to rent a dedicated line to access the GGSN equipment of the mobile company, which is high in cost, high in security, stable and reliable. For systems with very high security requirements, a hybrid access method of VPN access can be considered on the basis of dedicated APN access to further improve the security of the system.

1. VPN virtual private network mode: configure the VPN server in the internal network of the enterprise, and load the client side software with the function of VPN secondary virtual dialing at the mobile end point. Using VPN security technology, users are isolated from the Internet by accessing the internal virtual private network of the enterprise, and the entire data transmission process can be encrypted and protected to effectively avoid illegal intrusion.

2. Use the uniqueness of the SIM card to authenticate and authorize the user's SIM card mobile phone number, bind the SIM card number and APN on the network side, and delineate the scope of the user's access to a system. Only the SIM card mobile phone number belonging to the designated industry can access the dedicated APN. The mobile end point and DataPlatform use the dedicated APN allocated by China Mobile for wireless network access. The SIM card number of the ordinary mobile phone cannot call the dedicated APN.

3. For specific users, specific user IDs and passwords can be assigned through DataPlatform. Other users who do not have the user IDs and passwords assigned by DataPlatform will not be able to log in to the system, and the security of the system will be further enhanced.

4. Data encryption: The entire data transmission process is encrypted and protected through VPN.

5. Network access security identification mechanism: firewall software is used to set up network authentication and security prevention functions to ensure system security.

4. Conclusion

Using the wired method, the current cost of renting static IP is about 800~ 1500 yuan/month. Using the GPRS wireless method, the system traffic fee currently has two charging methods: monthly subscription system and data volume, which is 0.03 yuan K calculated according to the traffic, while the monthly subscription system is 20 yuan/month and has 1024 kBytes of traffic, which can meet the current environmental protection data collection system of the Provincial Environmental Protection Bureau. The actual data volume of the system is estimated to be gradually reduced in the future. For users such as the Environmental Protection Bureau, they enjoy benefits due to the low communication costs. In addition, since the access device can be moved, when the environmental protection observation station and the environmental protection information collection point are relocated, the device can be relocated and can continue to be used, which can protect the original investment of the user and is suitable for the characteristics of environmental protection collection work.

Using GPRS to build an environmental protection data collection system can not only well meet the needs of environmental protection information collection, but also, as a network operator, a mobile communication company will also obtain group users with stable business. With the increase in the number of users, mobile communication The company's earnings have also increased, mobilizing the enthusiasm of operators and meeting the requirements of simultaneous development of network construction and network applications.