CN103200707B - A kind of middleware of the meteorological data observation system based on wireless sensor network - Google Patents

Abstract

The invention discloses a middleware framework applied to a meteorological data observation system. As a bridge connecting a wireless sensor network and the Internet, data can be quickly transmitted between a sensor network end and a meteorological data observation center, and the operation is flexible and adaptable. wide range. The middleware of the meteorological data observation system based on the wireless sensor network provided by the present invention includes the CWSN subsystem connected with the meteorological wireless sensor network and the CPC subsystem connected with the meteorological data observation center,? Between CWSN subsystem and CPC subsystem through AD? The HOC network communicates; the CPC subsystem includes a CPC network connection module, a network adaptive module, a CPC automatic upgrade module and an instruction processing module, and the CWSN subsystem includes a serial port communication module, a CWSN network connection module, a WSN packet processing module, XML file processing module and CWSN automatic upgrade module.

Description

A Middleware of Meteorological Data Observation System Based on Wireless Sensor Network

technical field

The invention belongs to the technical field of wireless sensor network middleware, and in particular relates to a middleware of a meteorological data observation system based on a wireless sensor network.

Background technique

At present, the meteorological data observation system is divided into wired and wireless according to the data transmission mode. The wired transmission method can realize the collection of meteorological data well, but it has the disadvantages of high line cost, difficulty in laying in mountainous areas, and cumbersome maintenance. The wireless transmission method can provide high service quality and efficient bandwidth utilization while saving costs, so most of them currently use wireless transmission methods for data collection.

The meteorological data observation system usually includes a wireless sensor network, which is a wireless network composed of a large number of stationary or moving sensors, to cooperatively sense, collect, process and transmit the information of the perceived object in the geographical area covered by the network (such as temperature , sound, vibration, pressure, motion or pollutants, etc.), and ultimately send this information to the network owner. Wireless sensor network is the third wave of the world's information industry after computers and the Internet, and has become the strategic focus of a new round of global economic and technological development. With the deepening of research, wireless sensor networks will gradually integrate into people's daily life and various fields of social activities. If the Internet constitutes the logical information world and changes the way of communication between people, then the wireless sensor network integrates the logical information world with the objective physical world, changing the interaction between people and nature. Way. People can obtain a large amount of information of the objective world through wireless sensor networks at any time, any place, or even under any environmental conditions, which greatly expands the functions of the network and the ability of human beings to understand the world.

A wireless sensor network generally includes a sensor node (sensornode) and a sink node (sinknode). After the wireless sensor network is formed, various sensor nodes collect data, but due to the limited resources of each sensor node, it is impossible to have a large enough network communication capability, and the collected data is even less likely to be transmitted to a remote data monitoring center. However, there are still many problems such as high power consumption, inconvenient data acquisition, poor operability, low level of intelligence, and unstable data communication.

Contents of the invention

In order to solve the above problems, the present invention discloses a middleware architecture applied to the meteorological data observation system, which serves as a bridge connecting the wireless sensor network and the Internet, and can quickly transmit data between the sensor network end and the meteorological data observation center , Flexible operation and wide adaptability.

In order to achieve the above object, the present invention provides the following technical solutions:

A middleware of a meteorological data observation system based on a wireless sensor network, including a CWSN subsystem connected to a meteorological wireless sensor network and a CPC subsystem connected to a meteorological data observation center. The communication between the CWSN subsystem and the CPC subsystem is through ADHOC network for communication;

The CPC subsystem includes a CPC network connection module, a network self-adaptation module, a CPC automatic upgrade module and an instruction processing module,

in,

The CPC network connection module is connected with the CWSN subsystem through the ADHOC network, and connected with the meteorological data observation center through the Internet, receives the data sent by the CWSN subsystem and forwards it to the server, receives the data sent by the server and sends it to the CWSN subsystem;

The network adaptive module starts when the CPC subsystem is connected to the internet for the first time, and adjusts the way of accessing the network according to the current connection status between the CPC system and the network;

The instruction processing module is used to judge and process the instructions sent by the meteorological data observation center;

The CPC automatic upgrade module obtains executable files that can be directly run on the embedded platform from the meteorological data observation center, updates existing running programs, or adds running programs that do not exist on the embedded platform;

Described CWSN subsystem comprises serial port communication module, CWSN network connection module, WSN packet processing module, XML file processing module and CWSN automatic upgrading module:

in,

The serial port communication module is used to receive the data sent by the wireless sensor network and transmit the data to the WSN packet processing module for processing, receive instructions from the CPC subsystem and transmit them to the wireless sensor network;

The WSN packet processing module is used to analyze the WSN data packet received from the serial port communication module and transmit the parsed data to the XML file processing module, and encapsulate the data transmitted from the XML file processing module into a WSN data packet and send it to the serial port communication module ;

The XML file processing module is used to analyze the XML file sent from the CPC system and transmit it to the WSN packet processing module, generate an XML file from the data transmitted from the WSN packet processing module and send it to the CWSN network connection module;

The CWSN network connection module is used to connect the CPC subsystem and perform data communication with the CPC subsystem;

The CWSN automatic upgrade module obtains the executable file of the meteorological data observation center that can be directly run on the embedded platform through the CPC subsystem, updates the existing running program, or adds a running program that does not exist on the embedded platform.

As a preferred solution of the present invention, the network adaptive module automatically selects a smooth network for connection according to the sequence of Ethernet, wireless local area network, and 3G network.

Compared with the prior art, the present invention has the following advantages and technical effects:

1. Using middleware as the sensor network terminal and meteorological data observation center has the characteristics of high efficiency, real-time response, high reliability, low power consumption, strong anti-interference ability, etc., and has good versatility.

2. The CWSN subsystem and the CPC subsystem in the middleware form an AdHoc network. In this type of network, all nodes are equal, and there is no need to set up a central node. In this way, when two nodes cannot communicate directly, they can pass through multiple intermediate nodes. Node forwarding to achieve data exchange, so it has strong invulnerability.

3. Each system in the middleware can move quickly according to the needs, so as to realize the dynamic change of the network topology to meet the requirements of different occasions.

4. Whether it is the CPC system or the CWSN system, the program can be automatically updated, which provides a way for the automatic upgrade of middleware deployed in unmanned monitoring areas.

5. The middleware can select the physical link according to the existence of the physical link, and finally select the most practical channel, which has strong adaptability.

6. The middleware is developed and run on the embedded platform. Due to the inherent characteristics of the embedded device, the middleware is highly integrated.

Description of drawings

Fig. 1 is the schematic diagram of the middleware structure provided by the present invention;

Fig. 2 is the workflow diagram of CPC network connection module;

Fig. 3 is a schematic diagram of information interaction between the CPC automatic upgrade module and the data observation center;

Fig. 4 is the workflow schematic diagram of CPC automatic upgrade module;

Figure 5 is a schematic diagram of information interaction between the CWSN automatic upgrade module and the data observation center;

detailed description

The technical solutions provided by the present invention will be described in detail below in conjunction with specific examples. It should be understood that the following specific embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention.

The present invention is developed and operated on an embedded platform, and what the present invention uses is an ARM11 development board based on the S3C6410 kernel, but other embedded devices can also be developed and operated. The structural principle of the middleware of the meteorological data observation system based on the wireless sensor network is shown in Figure 1, including the CWSN subsystem connected with the meteorological wireless sensor network and the CPC subsystem connected with the meteorological data observation center server, the CWSN subsystem and CPC subsystems communicate through the ADHOC network. The middleware provided by the invention acts as a bridge between the meteorological wireless sensor network and the server of the meteorological data observation center to realize the information exchange between them. There is a many-to-one relationship between the CWSN subsystem and the CPC subsystem. A large number of CWSN systems send connection requests to the CPC subsystem. The CPC subsystem responds to these clients one by one through judgment, and can realize the client data forwarding to the data observation center. function. On the contrary, the observation center can also send messages to the CWSN system through the same principle.

The CPC subsystem includes a CPC network connection module, a network self-adaptation module, a CPC automatic upgrade module and an instruction processing module:

Among them, the CPC network connection module is connected with the CWSN subsystem through the ADHOC network, and connected with the meteorological data observation center platform through the Internet.

Specifically, the CPC network connection module includes three threads during execution, the main thread, the sending and receiving client thread, and the thread connecting to the PC server. It also creates buffer 1 for storing data uploaded by the client and for storing The buffer 2 of incoming data, its flow chart is shown in Fig. 2. The workflow of these three threads is described in detail below:

main thread. The main thread is mainly responsible for connecting with the CWSN subsystem and creating two sub-threads. When the program is running, it first obtains the server address for logging in to the remote service application layer. If the address is not obtained, the program prints an error message and exits the program; if it obtains the correct address, it creates a thread for connecting to the remote server, and then creates a thread for sending and receiving client data. Create a local server through socket, bind, listen, and accept functions and continuously monitor the connection request of the CWSN subsystem. Once there is a client request, the main thread will send a random code of one byte, and then verify the verification code sent by the client. , if the verification is successful, store the socket of the corresponding client in the socket array, and if it is unsuccessful, disconnect and return to the part that monitors the connection of the CWSN subsystem.

Send and receive client threads. When the CPC subsystem receives the data uploaded by the client (that is, the CWSN subsystem), the CPC will enter the sending and receiving client thread part to determine whether there is data in the data buffer area 1, and if so, wait for the data in the data buffer area to be processed , if not, store the data in data buffer 1. Then judge whether there is data in the data buffer area 2, if not, return to judge whether there is data in the buffer area 1, if there is, enter to judge whether the content in the data is for the CPC subsystem, if not for the CPC subsystem, send the data Go to each CWSN subsystem, and finally empty the data buffer area 2, and return to the beginning part of the sending and receiving client thread. If it is for the CPC subsystem, send the data in the buffer area 2 to the instruction processing module, and let the instruction processing module perform corresponding processing.

Connect PC server thread. On the contrary, when the CPC receives data from the service application layer (that is, the data observation center), it will judge whether there is data in the data buffer area 2, if there is data, it will wait, and if there is no data, it will store the data in the data buffer area 2. Then judge whether there is data in the data cache 1, and then call the send() function to send the data to the remote server, then clear the content in the data cache 1, and return to judging whether there is data in the data cache 2, and vice versa Return directly to the judgment data buffer area 2 part.

The network adaptive module is started when the CPC subsystem is connected to the internet for the first time, and the module adjusts the way of accessing the network according to the current connection status between the CPC system and the network. In the case of complete basic network facilities, we can choose one of Ethernet, wireless LAN, and 3G network. The stability of Ethernet is better than the latter two networks, but not all areas have Ethernet interfaces, such as mountainous areas, islands or sparsely populated areas. When the basic facilities are not perfect, we can choose wireless local area network. As long as there is a wireless router connected to the observation center, the wifi module of our CPC subsystem can be connected to the service application layer. If the above two situations cannot be satisfied, then we can only choose 3G network. Although the stability and cost performance of the network are not as good as the above two types, this kind of network has convenient connection and wide coverage, which can fully meet the needs of our system. Require. During the execution process, the network adaptive unit first starts the Ethernet card. Through the ping command of the ICMP protocol, if the physical link between the Ethernet card and the router exists, it will return a fixed value. By comparing the returned value with the fixed value, the CPC can be judged. The information between the system and the remote center shows whether the link of the control platform is smooth. If it is smooth, the unit exits. If it is not smooth, set the parameters of the wifi network card and start the wifi network card. Then use the ICMP protocol to test the network again. If it is successful, it will exit. If it is unsuccessful, it will run the 3G network card startup program. The 3G network card startup program is an executable dialer program written in shell script language. In order to better implement the USB3G dial-up function, a service program is running in the background. This program is set to run automatically when the machine is turned on, so when we execute the 3G network card startup program, it will automatically send instructions through this background service program to complete the process. 3G dialing.

The instruction processing module is used to judge and process the instructions sent by the meteorological data observation center, such as: upgrade instructions, time adjustment instructions, etc. If the instruction processing module parses out that it is an instruction to upgrade the cpc subsystem, the CPC system will It will immediately execute the CPC automatic upgrade module and wait to receive the configuration file sent by the meteorological data observation center platform.

CPC automatically upgrades modules. Since the CPC subsystem is the server side relative to the CWSN subsystem, and the CPC subsystem is the client side relative to the data observation center, the program update and upgrade of the CPC subsystem mainly involves two aspects. The first server The program of the terminal, the program of the second CPC client. The information interaction between the CPC automatic upgrade module and the data observation center when it is upgraded is shown in Figure 3. For the server, it is mainly the configuration of the ftp server. The data observation center platform sends the client program update command to the CPC subsystem, and the CPC subsystem Confirm after obtaining the client instructions, and after receiving the confirmation information, the data observation center platform sends ftp login and update program information to the CPC subsystem, and the CPC subsystem performs corresponding operations according to the received configuration information, and starts if it meets the requirements of the download program Download the program. After the program is downloaded, the downloaded program will be judged, and the workflow is shown in Figure 4. When the program is downloaded and received, parse the downloaded xml file again, extract the file size information, that is, the size of the file_size node, calculate the size of the downloaded update program and record it as curr_size, compare file_size and curr_size: if the size values are not equal, it means that the program is in the program If an error occurs during the downloading process, re-download the program; if the values are equal, the program download is successful. If the program is successfully downloaded, close the running program, modify the name of the old program, and then directly start the new program just downloaded: if the new program can run successfully, delete the old version of the program and the program configuration file in xml format just downloaded; If the new program does not run successfully, restart the old version of the program.

The CWSN subsystem includes a serial communication module and a CWSN network connection module, wherein the serial communication module communicates with the wireless sensor network, and the CWSN network connection module is connected to the CPC subsystem. Because the file in XML format has its unique advantages, we choose to transfer data through the file in XML format between the CWSN subsystem and the CPC subsystem, and the data sent by the wireless sensor network is WSN data packets, so the CWSN sub-system The system also includes a WSN packet processing module and an XML file processing module for data parsing and encapsulation.

The serial port communication module is mainly responsible for the communication between the wireless sensor network and the middleware. When the meteorological sensor in the wireless sensor network collects data, it will regularly send the data to the only sink node in the network, and then the sink node will send the data just received The received meteorological data is sent to the CWSN system. This module is used to receive the data sent by the aggregation node in the wireless sensor network and transmit the data to the WSN packet processing module for processing, and transmit the instructions received from the CPC subsystem to the wireless sensor network. Specifically, the serial program communication unit is responsible for obtaining information from the convergence nodes in the wireless sensor network, mainly including the working status of the sensor nodes, the collected environmental parameters, and the execution of remote server commands. Open the ttySAC1 serial port file through the open() function, and execute the next step according to whether it is opened correctly. If the opening is unsuccessful, the program will always execute the open() function. If the opening is successful, set the parameters of the serial port. , The parameter setting mainly includes baud rate, data bit, stop bit and parity bit.

The CWSN network connection module uses the Adhoc network to connect the CWSN system with the CPC system through the aodv routing protocol, and realizes the information exchange between the CWSN and the CPC system through network programming.

The WSN packet processing module is used to parse and encapsulate WSN data packets; this module parses the WSN data packets received from the serial port communication module and transmits the parsed data to the XML file processing module, and encapsulates the data transmitted from the XML file processing module into WSN data packet, add the corresponding information of ARMNode to the packet when encapsulating, where ARMNode is a unique identifier used to identify the hardware device where each CWSN subsystem is located (it can be called a CWSN address), and use an IP address to identify each computer same thinking. If the wireless sensor network wants to exchange data with the CWSN subsystem, it must formulate a reasonable data packet format, that is, WSN packet. The following table 1 is a description of the package format:

Table 1

All communication data between the CWSN subsystem and the wireless sensor network must start and end with the fixed character "0x1A". Length represents the size of this packet. The next byte is the unique identification number of the sensor node. Type is used to represent the type of sensor node. Data is the part of the data collected by the sensor. Our sensor node is a module with multiple sensors. For example, sensors with temperature, temperature, and air pressure are integrated into a sensor node, and these sensors share a radio frequency module. The two bytes of the data part represent a data value. Currently, our sensor node can support 3 sensors, so the size of the data is specified as 6 bytes. Workingstate represents the working state of the sensor node, and Remainingpower represents the remaining power, which is explained by whether it is in power warning. AcquistitionCycle is the data sending cycle of the RF module. The analysis process of the WSN packet processing module is as follows: first read the first and last bytes of the obtained WSN data packet, and judge whether it is 0x1A. If one of them is not, the data packet will be discarded. If the first and last bytes of the WSN data packet meet the requirements, read the second and third bytes to determine whether they are equal to the total number of bytes in the data packet. If not, it means that the data packet is damaged, and discard the packet ; If they are equal, identify the type of data according to the content of the next byte, and store the data of the remaining bytes in the corresponding database table. Contrary to the WSN data packet analysis process, when the CWSN subsystem sends a command to a sensor in the wireless sensor network, the format of the sent command packet must be recognized by the sensor node, otherwise the command packet will be treated as an invalid packet by the sensor node , so the encapsulation process is to add necessary format characters on the basis of the data to be sent to make it conform to the WSN data packet format.

The XML file processing module is used to parse and generate XML files; this module parses the XML files sent from the CPC system and transfers them to the WSN packet processing module, generates XML format files from the data transmitted from the WSN packet processing module, and parses them. The process of generating the XML file is similar to the process of processing the WSN package, and will not be repeated here. In this system, the xml files are classified by type, mainly including files that transmit sensor data regularly and response files that respond to commands from remote data centers. The idea of generating files in these two xml formats is the same, they first extract the corresponding data from the database or from the WSN file processing module, create xml format files through libxml2 library functions, and finally convert the files into data packets way to send out. The XML file processing module also includes the command processing function similar to the command processing module in the CPC subsystem, which is used to judge and process the commands sent by the meteorological data observation center through the CPC subsystem. If the command processing module parses out that it is a CWSN The subsystem performs program upgrade instructions, and the CWSN subsystem will immediately execute the CWSN automatic upgrade module and wait to receive the configuration file sent by the meteorological data observation center platform.

CWSN automatic upgrade module, when the data observation center has a new version of the CWSN program, it will send a program upgrade command to the CWSN subsystem, and the CWSN system will send a response message to the data observation center after receiving the program upgrade command, indicating that the program can now be received The data observation center receives the response message from the CWSN system. If the configuration file is confirmed to be received, the data observation center will send the configuration file in xml format to CWSN. The format of the file is the same as the xml format in the program upgrade of the CPC system. When the CPC automatic upgrade module is upgraded, the information interaction between the CPC subsystem and the data observation center is shown in Figure 5. After the CWSN main program receives the configuration file of the program update program, it determines whether the CWSN main program is to be upgraded. If it is upgraded, it will send a message confirming the download program to the data observation center, and finally complete the function of program download.

The technical means disclosed in the solutions of the present invention are not limited to the technical means disclosed in the above embodiments, but also include technical solutions composed of any combination of the above technical features.

Claims (2)

1. a kind of middleware based on the meteorological data observation system of wireless sensor network, it is characterized in that: comprise the CWSN subsystem that is connected with meteorological wireless sensor network and the CPC subsystem that is connected with meteorological data observation center, CWSN subsystem and CPC The subsystems communicate through the ADHOC network; The CPC subsystem includes a CPC network connection module, a network self-adaptation module, a CPC automatic upgrade module and an instruction processing module, in, The CPC network connection module is connected with the CWSN subsystem through the ADHOC network, and connected with the meteorological data observation center through the Internet, receives the data sent by the CWSN subsystem and forwards it to the server, receives the data sent by the server and sends it to the CWSN subsystem; The network adaptive module starts when the CPC subsystem is connected to the internet for the first time, and adjusts the way of accessing the network according to the current connection status between the CPC subsystem and the network; The instruction processing module is used to judge and process the instructions sent by the meteorological data observation center; The CPC automatic upgrade module obtains executable files that can be directly run on the embedded platform from the meteorological data observation center, updates existing running programs, or adds running programs that do not exist on the embedded platform; Described CWSN subsystem comprises serial port communication module, CWSN network connection module, WSN packet processing module, XML file processing module and CWSN automatic upgrading module: in, The serial port communication module is used to receive the data sent by the wireless sensor network and transmit the data to the WSN packet processing module for processing, receive instructions from the CPC subsystem and transmit them to the wireless sensor network; The WSN packet processing module is used to analyze the WSN data packet received from the serial port communication module and transmit the parsed data to the XML file processing module, and encapsulate the data transmitted from the XML file processing module into a WSN data packet and send it to the serial port communication module ; The XML file processing module is used to analyze the XML file sent from the CPC subsystem and transmit it to the WSN packet processing module, and generate an XML file from the data transmitted from the WSN packet processing module and send it to the CWSN network connection module; The CWSN network connection module is used to connect the CPC subsystem and perform data communication with the CPC subsystem; The CWSN automatic upgrade module obtains the executable file of the meteorological data observation center that can be directly run on the embedded platform through the CPC subsystem, updates the existing running program, or adds a running program that does not exist on the embedded platform. 2. the middleware of the meteorological data observation system based on wireless sensor network according to claim 1, is characterized in that: described network self-adaptive module is according to the order of ethernet, wireless local area network, 3G network, automatically selects unobstructed network to carry out connect.