The Design Of Earthquake Intensity Rapid Alarm Terminal Based On ARM

The earthquake disaster presents a serious threat to people's life and property.Earthquake prevention system in China is currently in the primary stage and an effective earthquake prevention system has not yet been established in our country.In view of the current background,an earthquake early warning terminal,as part of earthquake early warning system,is designed in this paper.The major function of the terminal is to complete real time acquisition of acceleration,and determine whether the earthquake occurred through analysis and processing of data.Seismic information should be calculated by the terminal when earthqu eke happened.Meanwhile,seismic data should be stored and transmitted to the network center.The hardware design of the system,detailed requirement analysis has been done in this paper in the first.Corresponding chip type is selected according to the a ctual situation.And the hardware system of earthquake early warning terminal is composed by ARM Cortex?-A8 microprocessor and ADXL355 accelerometer.The core board should control the real-time acquisition of the accelerometer and corresponding processing of the acquisition data.GPS timing module is added to the system in order to ensure the punctuality accuracy of the terminal.For the software part,the whole framework of the system is designed according to producer consumer model in multithreaded programming in use of semaphore and mutex in the first.The whole framework of the system can ensure that the system can run reliably for a long time and switch between catching mode and triggerring mode at any time.A reasonable data structure is designed to st orage the acceleration data according to the actual situation.And data replacement algorithm is proposed in order to prevent the overflow of the memory space so that the system can run reliably for a long time.Further more,some data processing algorithms is designed to completing the earthquake warning function,include IIR digital filter,long and short window algorithm for earthquake events determination,the algorithm of calculating the seismic data and seismic data compression algorithm.This paper a lso completed the extraction and analysis of the acceleration raw data as well as GPS data frame.The network communication between the terminal and the network center is completed based on TCP/IP model.Further more,the function of real-time responding to the command of the network center is realized through I/O port multiplexing technology.At last,the overall function and performance index of the terminal is tested using the data which is catched by the terminal.