Development of Wireless Magnetoresistive Sensor Network for Unexploded Ordnance and Landmine Detection
Type of Degreethesis
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This thesis summarizes the effort toward developing a passive/active magnetoresistive (MR) sensor array for unexploded ordnance (UXO) realized with wireless sensor network technology. In recent years, the rapid development and research on wireless sensor networks (WSN) has enabled application of WSN technology in a variety of areas．This thesis analyzed the characteristics and advantages of the WSN approach in detail and discussed the feasibility of WSN implementation in a UXO and detection system. An overall system design is given with the passive sensor array dedicated for large area magnetic field survey, and the active array for pin-point detection and target discrimination. The initial design utilizes off-the-shelf components and software to minimize engineering costs. The design scheme of a distributed WSN node is introduced, with design of a WSN sensor platform based on the Silicon Labs C8051F912 microcontroller (MCU) and Si4431 radio frequency (RF) integrated circuit (IC) combination realized to operate on the 915MHz license free Industrial Scientific Medical (ISM) band. The passive sensor node is realized with the HMC5843 digital magnetometer IC and the active node is realized with HMC1053 magnetic sensor (both HMC sensors from Honeywell) with customized analog circuits. The WSN is designed with master-slave state machine with star topology that supports up to 255 nodes per master node. The network protocol is comprised of a Si4431 physical layer, an EZMacPro media access control (MAC) layer, and a customized application layer. The fabricated passive and active sensor node prototypes are compact and light weight. Lab testing demonstrates that the overall system performance goal has been met. A pilot production of the WSN nodes is proposed for field testing to further verify the effectiveness of the passive/active wireless MR sensor UXO/mine detection array.