The Technological Research For Underground Metal Object Detection And Location Based On Wireless Sensor Network

During weapons are been tested process, it is necessary to recover their shells after they are fired to analyze the shells performance. The position of shells need to be acquired to process the recovered projectiles. Currently, there is no effective method to get the position of impact area, so it is very significant to study the impact point detecting and positioning technology.When the shells land on ground, they will have impact on the ground and seismic waves will generated. Multiple sensor nodes were set up around the explosion point to receive seismic signal. The landing position of the projectiles can be inferred by analyzing and processing the received seismic signal to achieve the position of the point of impact.Wireless sensor network has been widely used in the fields of military, environmental, health and others with its self-organizing, rapid deployment, high fault tolerance, concealment and other advantages. Wireless sensor technology was applied in the positioning system to implement wireless data transmission. The main research includes the following:The propagation characteristics of the received seismic waves were analyzed. Based on TDOA positioning principle, the author have completed the whole system design scheme of detection and location system by deeply studies of the detecting and positioning principle and method which based on the seismic signal.Based on the overall design scheme of the system, the author have determined the overall hardware architecture and completed circuit design of the system, such as STM32F103 processor as the core of the signal processing circuit and JN5148 wireless module as the core of wireless sensor nodes circuit. Then, the relevant software design of this system was completed by adopting the Keil uVision4 and CodeBlocks software development environment.The projectile impact point positioning simulation system was formed based on the studies above, and the synchronization performance tests of the vibration signal conditioning circuit and time synchronization circuit were conducted. Besides, the effective detection Range of the seismic detector was determined. Then combining with single base array mode and TDOA positioning algorithm, the placing position of the projectiles were acquired by adopting artificial simulation vibration signal.