chrispeng [ad_1]
Wireless Sensor Networks (Wireless Sensor Networks, WSN) is a self-organizing wireless network composed of a group of randomly distributed miniature sensors that integrate sensors, data processing units and communication modules. Its purpose is to cooperatively perceive, collect and process the information of monitored objects in the network coverage area, and transmit it to the information acquirer. WSN technology integrates sensor technology, embedded computing technology, network technology, distributed information processing technology and communication technology. It has great application value in military, industrial, medical, transportation, environmental protection and many other aspects. It is being affected by various technologies and military powers. More and more attention.
Because WSN detection nodes can be deployed in large numbers in the vicinity of sensing objects through aircraft broadcast or manual arrangement, etc., they can continuously obtain various information of the sensing objects and provide first-hand information for military commanders’ decision-making. Therefore, in contemporary information warfare It has broad prospects for military applications.
my country’s current WSN technology research has taken on a preliminary scale, but the military application research of WSN technology is still in its infancy.
1 Composition and characteristics of WSN
1.1 The composition of WSN
A typical WSN system is mainly composed of information management nodes, sink nodes (Sink Nocle), sensor nodes (Sensor Node) and related networks.
The sensor node is composed of a large number of cheap miniature sensor modules deployed near the sensing object, and its purpose is to cooperatively sense, collect and process the information of the sensing object in the network coverage area, and send it to the sink node. Each module forms a multi-hop self-organizing network system through wireless communication, and the data collected by sensor nodes is transmitted to the sink node hop by hop along other sensor nodes. A WSN system usually has a large number of small, low-cost sensor nodes.
Convergence nodes and sensor nodes constitute the underlying data collection and transmission network system. Although a single node has limited functions and the collected data is not accurate enough, a large number of nodes with certain computing, storage and communication capabilities cooperate with each other to form a highly advanced network system. With the invulnerable network system, the accuracy and breadth of the collected data can be greatly improved, and the returned data can be used as a reference for user decision-making.
The sink node transmits the monitoring data to the management node through a communication satellite or other communication network. Through the configuration and management of the entire system, the management node realizes the release of monitoring tasks for each node in the system and the collection and processing of monitoring data. The typical structure of WSN is shown in Figure 1.
figure 1
1.2 Features of WSN
WSN has many unique advantages that other information detection systems and network systems do not have, but also has certain limitations.
1.2.1 Advantages
(1) Strong survivability
A large number of sensor nodes densely distributed in the monitoring area of WSN have equal status, and there is no strict control center. Each sensor node can join or leave the network at any time without affecting the normal operation of the entire network. When some sensor nodes cannot work normally due to environmental interference or man-made damage, a large number of randomly distributed sensor nodes can coordinate and complement each other and dynamically connect to form a new network system to ensure that the damage of some sensor nodes will not affect the global task. Therefore, WSN has strong survivability in the harsh battlefield environment.
(2) High accuracy and reliability. Because the WSN system can deploy a large number of low-cost sensor nodes in the monitoring area, the sensor nodes can be in close contact with the detection target, which greatly eliminates the impact of environmental noise on system performance. Through the mixed application of multiple sensors, the monitored objects can be monitored from different spatial perspectives while improving the detection performance indicators. The multi-node joint and multi-directional information integration can effectively improve the signal-to-noise ratio and form a larger coverage area. Real-time detection of the area, thereby improving the accuracy of monitoring and overcoming the technical difficulties of independent systems such as satellites and radars.
The large-scale deployment of sensor nodes in the WSN system makes the WSN usually have higher node redundancy, network link redundancy and data collection redundancy, providing strong fault tolerance for the entire system. In addition, by adjusting the network topology with the help of individual mobile nodes in the sensor nodes, the shadows and spots in the detection area can be effectively eliminated, which further reduces environmental noise and improves the accuracy of detection.
(3) Strong self-organization ability
WSN is a peer-to-peer network of nodes. Each node has a routing function. There is no strict central control node in the network. The deployment of its work does not depend on any preset network infrastructure. After the nodes are turned on, they can quickly and automatically form an independent network through self-coordination and automatic deployment.
(4) Strong scalability
WSN is a dynamic network, and nodes in the network may exit or join the network for various reasons at any time. At this time, the original WSN can effectively accommodate or eliminate changed nodes, quickly form a new network and continue the original work without outside help.
1.2.2 Limitations
The WSN system, which is composed of low-cost and low-power miniature sensor nodes and works in self-organizing mode, also has certain limitations:
(1) The finiteness of energy
The sensor nodes in WSN are small in size and generally rely on batteries with limited energy for power supply. Its special application field and large-scale number of applications determine that it cannot be updated during use. Once the battery is exhausted, the node will “die”. Therefore, how to improve energy efficiency and node life cycle in the WSN design process is the first important factor that needs to be considered.
(2) The limitation of hardware resources
The WSN system has very high requirements for sensor nodes, such as micro-embedded systems that need to be deployed on a large scale, including small size, low price, and low power consumption. Restricted by these requirements, the computing power, program space, and memory space of sensor nodes are very limited. At the same time, WSN-oriented algorithm calculation design should be as simple as possible and easy to implement on sensor nodes.
(3) The limitation of communication capacity
Since the energy required for wireless communication is proportional to the nth power of the communication distance, as the communication distance increases, the energy consumption of sensor nodes in WSN will increase sharply. Constrained by energy factors, nodes must consider increasing the communication distance under the conditions of smooth communication and normal life cycle. At the same time, due to the influence of external geographical conditions and natural environment, the wireless communication performance may change frequently, and there will be frequent communication interruptions, which also greatly restricts the communication capability of the WSN system.
2 Application of sensor networks in the military
In information warfare, the timely acquisition and response of battlefield information is crucial to the impact of the entire battle. Because WSN has the characteristics of strong survivability, high detection accuracy, and low cost, it is very suitable for use in the harsh battlefield environment to perform battlefield reconnaissance and monitoring, target positioning, war effectiveness* estimation, nuclear, biological and chemical monitoring, homeland security protection, and border surveillance. Wait for the task.
2.1 Battlefield reconnaissance and monitoring
The basic idea of battlefield reconnaissance and monitoring is to deploy a large number of WSNs on the battlefield to collect and relay information, and filter a large amount of raw data; then transmit important information to the data fusion center to integrate a large amount of information into one A panoramic view of the battlefield to meet the requirements of combat forces to “know oneself and the enemy” and greatly enhance the commander’s level of perception of the battlefield situation.
A typical WSN application method is to use aircraft to spread a large number of micro-sensor nodes in the battlefield domain, and form a network by itself to collect, transmit, and fuse battlefield information. The system software interprets the data content transmitted by the sensor nodes and integrates them with related information such as roads, buildings, weather, unit locations, and other WSN information to provide a dynamic, real-time or near-real-time update to the battlefield commander. The battlefield information database provides intelligence basis and services for each combat platform to formulate combat action plans more accurately, and enables a qualitative leap in intelligence reconnaissance and acquisition capabilities.
The monitoring of the battlefield can be divided into monitoring of one’s own side and monitoring of the enemy, including military operation reconnaissance and non-military operation monitoring. By attaching various sensors to own personnel and equipment, and sending the information collected by the sensors to the command post through the convergence node, and at the same time fusing other information from the battlefield, a complete battlefield situation map can be formed to help the commander understand in time and accurately. *, the deployment and supply of weapons, equipment and military materials.
A large number of sensors are deployed on the enemy’s position by aircraft or other means to detect and identify potential ground targets. This enables one to observe the enemy’s deployment at close range in a long-range, accurate, low-cost, and concealed manner, quickly and fully. Collect information that is conducive to combat in a directional manner, and quickly adjust and deploy new WSNs according to the battle situation to detect the enemy’s attempts and the degree of threat to us in time. By deploying and controlling WSN in key areas and possible routes, strict monitoring of the enemy can be achieved all-weather.
2.2 Target positioning
The node that perceives the target information in the WSN broadcasts (wirelessly transmits) the perception information to the management node, and then the management node fuses the perception information, and the process of judging the target location is called target positioning. Target positioning is one of the important applications of WSN, providing accurate target positioning information for fire control and guidance systems, so as to achieve precise strikes on predetermined targets.
Because WSN has the characteristics of strong scalability, real-time and good concealment, it is very suitable for tracking and positioning moving targets and providing the command center with real-time position information of the tracked object. The target location application method of WSN can be divided into three stages: detection, location, and report. In the detection phase, each sensor node randomly “starts” to detect possible targets, calculates its distance to the target after the target appears, and broadcasts information to the network including the location of the node and the distance to the target. In the positioning stage, each node obtains the target’s position information through methods such as maximum likelihood, trilateral measurement or triangulation according to the received target position and its own position information, and then enters the reporting stage. In the reporting phase, WSN will broadcast messages to sensor nodes close to the target to start and join the tracking process. At the same time, WSN transmits target information to the management node or command post through the sink node to achieve precise target positioning.
In 2003, the Network Embed and System Technology project led by the US Defense Advanced Research Projects Agency successfully verified the accurate positioning capability of WSN technology. The project uses multiple cheap audio sensor nodes to coordinately locate enemy snipers and mark them in the personal computers of all combatants. The positioning accuracy in the three-dimensional space can reach 1.5 m, the positioning delay can reach 2 s, and it can even show the enemy. The difference between the kneeling posture and the standing sniper shooting has brought a qualitative leap in the combat situation awareness of commanders and combatants.
[ad_2]
