| Petroleum is an important strategic material of the country. And it is closely linked with economic development, political security and military security of the country. To protect petroleum security of the country, dependence on foreign petroleum resources should be reduced, and our own petroleum exploration industry chain should be established. And petroleum exploration instrument is one important link of the chain.Nowadays, in order to meet the requirements of high-resolution exploration, small trace intervals, more channels, one unit one channel are characteristics of modern petroleum exploration equipments. And the exploration system is essentially a specified sensor network.The architecture, OS, protocol and distributed data processing method of a sensor network are closely related with a specified application. And the sensor network is connected to the physical world. This adds uncertainty to execution. So, for a sensor network, the application should be studied thoroughly, including its operating system and network stack. Usually, it is not possible to reveal actual performance of algorithms and protocols by simulation only, without considering characteristics of real platforms. So it is very difficult to simulate behaviors that relate to operating systems or hardwares, especially low level operations, such as interrupt handling, task scheduling and memory management. But these low level operations effect system performance a lot. And some algorithms and protocols run well in a simulation environment, but perform poorly when running in a real node. So such simulations can not meet the requirement for completeness and fidelity. And because of differences between a simulation platform and a real node, algorithms and protocols have to be reimplemented for different ploatforms. And the reusability of the code is limited, the development cycle is lengthened, and the code maintenance workload is increased. Once algorithms or protocols are changed, researchers have to implement the same changes for different platforms. And for different platforms, the same functionality has to be implemented with different approaches, especially for a cross-layer protocol design whose applications can access low level hardware directly for efficiency. So for codes that tied to hardware, only algorithm ideas are the same, implementations are different for different platforms. And the code reusability is not possible.Based on the above considerations, a FreeRTOS simulator is implemented with its tasks and interrupts simulated by threads and signals respectively. And the simulation platform is implemented by integrating the FreeRTOS simulator with a network simulator. And the completeness, fidelity, and reusability of the sensor network simulation platform are enhanced without losing the scalability of the platfrom.In chapter 1, oil and gas exploration methods, seismic exploration instruments development history, and several topologies used by current seismic exploration instruments are introduced. And the concept of a seismic sensor network is given based on topologies of instruments. Methods for researching networks and requirements of a network simulator are analysed. To overcome the shortage of current network simulators, research of the dissertation is proposed.In chapter 2, the concept of seismic resolution and resolution criterions are introduced. And quantitative calculation of seismic resolution, and factors that impact seismic resolution and scale of a seismic sensor network are analysed. Some high resolution exploration methods and their impacts on trace intervals are presented. And the trend of seismic exploration instruments are analysed.In chapter 3, characteristics and design guide of a seismic sensor network are introduced. And some routing protocols and cross-layer protocol design methodologies for sensor networks are presented. Transmission technologies adopted by the 5th and the 6th seismic exploration instruments and typical instruments that use these technologies are demonstrated. On the basis of existing wireless technologies, a wireless seismic sensor network is analysed. In order to construct suitable topology, and find out suitable algorithms and protocols for a seismic sensor network, network simulation should be adopted.In chapter 4, design and implementation of a multi task embedded operating system simulator are presented. On the basis of characteristics and requirements of a embedded operating system simulator for our seismic sensor network simulation platform, FreeRTOS is chosen as the candidate. After introducing FreeRTOS, and its level in the system, methods for simulating embedded operating systems are compared, and the simulator should be implemented by a process. Tasks and hardware interrupts are simulated by threads and signals respectly, and they compose the core of FreeRTOS simulator. Hardware peripherals are simulated by asynchronous I/O with layered design. And the method for implementing FreeRTOS simulator is also suitable for other light weight multi task embedded operating systems. The memeory consumption is 120KB for FreeRTOS simulator core, and about 10KB for each task under test. So, if a FreeRTOS simulator that runs on a seismic sensor network node contains 4 tasks, it only consumes less than 200KB memory.In chapter 5, the method for integrating FreeRTOS simulator with a network simulator is presented. After comparing some network simulators, ns-3 is chosen for its high performance and low resource consumption. At synchronization points, ns-3 and FreeRTOS simulator are synchronized, and data are transmitted. And the simulation is considered to be real when 3 conditions are satisfied. The platform is tested with grid topology by flooding the entire network. The test shows that, for a simulation network with FreeRTOS simulator running on each node, memeory consumption of 1000 nodes is about 170MB.In chapter 6, ideas, methods and results of the entire work are summarized. Innovation points of the dissertation are described. And the goal of future work is pointed out.
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