Research On Technique Of Network-based Transducer In Earthquake-related Geo-electric Filed Observations

Geo-electric field observation has very important practical meanings in detecting earth interior electric structures and forecasting earthquake. This paper presents development situation in the world about geo-electric field observation and sensor technology at first. According to requirements of omnidirectional and multichannel spontaneous potential observation method, considering the situations of fieldwork, integrated stations and remotely unmanned observation, designs a multichannel, high resolution, pint-sized, network sensor system to realize data acquisition, transmission and form sensor network in omnidirectional, multichannel spontaneous potential observation. Finally, make tests of this network sensor system's characters in lab.Using embedded system technology and TCP/IP based network technology bring forward network sensor system based on layered model of IEEE1451 standard, by two CPUs, while one is for data acquisition module and the other for network service module. The SOC of C8051F02X acts as a core role in data acquisition module, and controls multi-chips of AD771X to accomplish the actions of data acquisition, storage and to give out digitalized data for network service module. While designing hardware of network service module, using low power chip EP93XX based on ARM architecture as a main CPU, to implement RS232 interface,memory access circuit,network access circuit etc. Using GPRS to implement wireless network considering these characteristics based on the GPRS data transmission technology, for example, broad covering area, quick data transmission speed, big capacity, low cost of system construction and automatic connecting to Internet,convenient maintenance,simple and quick promotion and so on. Also it can be accessed by wired network compatible to the current wired network used in earthquake forecasting filed. For the software design of network service module, under the support of wince OS, with the help of programming technique on EVC, COM technique, ASP technique, it makes flexible for data acquisition, data access, processing, network service, and also provides friendly UI.The experiment results of laboratory indicates that the network sensor system of this paper is reliable and stable and has realized high resolution data gathering, and real time data access and transmission, the results also include the well controlment of this network sensor system through network.