The Transmission Application Research Of Subdivision Cell Based On BD Short Message

With the improvement of 3S (Remote sensing, Geography information systems , Global positioning systems) ,especially the continuous development of wireless communication technology ,the need of spatial information technology is increasing and the constant demand for a convenient life is growing. Thus, a new technology—the comprehensive 3S and the spatial information mobile technique of modern communication come into shape. Spatial information service is the comprehensive 3S and the modern communication technique to provide the information and service on Geography position. The technologies above can be sorted into three kinds : the mobile positioning system, the integrated technique of mobile general basic platform of spatial information, and the mobile terminal technology. This paper explores the three aspects above respectively.The mobile positioning system adopts GPS and BD satellite system to realize the positioning of dual mode. The passive positioning of the GPS combines with the initiative positioning of the BD satellite system, which reduces the demand of the operating environment, increases the accuracy of the positioning, and avoids the policy interruption of the foreign positioning system at the key moment. The seamless positioning function can be achieved under the ordinary operation.The integrated technique of spatial information mobile mainly comprises two parts: The GIS and embedded GIS. The function module of the GIS is transplanted into the embedded GIS through the software reuse technology, which can make the code structure same and the function corresponded to reduce the re-work of the software development. The GIS adopts the remote sensing image of high definition based on hierarchical global grid technique. After the subdivision cell data of remote sensing high definition image ,the memory space can be reduced greatly and the burden of the communication can be relieved, which lies the foundation of the subsidiary system of the BD short message in the condition of narrow-band.The hardware constitution of the mobile terminal technique is: the high performance ARM CPU which is popular internationally, large-size LCD of high resolution, GPS and the positioning mode of BD dual mode, reliable lithium-ion battery of high capacity.The data source of the remote sensing becomes larger and more sophisticated in high time resolution, high spatial resolution and high spectral resolution. The two contradictions: (the performance of embedded equipment and the limitation of the memory space, high speed remote sensing and mass demand) provide a new challenge for the spatial mobile information service. This paper combines 3S technique with BD system to put forward the 3S+BD that is the spatial mobile information mode with the unique Chinese technique. With the subdivision cell as the transmission unit, the embedded GIS as platform, through the advanced image compression technique, the transmission application technique of subdivision cell based on BD short message was realized by the short message communication of BD satellite system.This paper focuses on: global subdivision, subdivision cell image compression technique, GPS and BD dual mode positioning technique, short message communication of BD satellite system and the exploitation technique of embedded GIS.The global subdivision has greater advantages on global, multi-resolution, supporting dimension variety, well-distributed spatial position and so on. The global subdivision stores remote sensing image data through STQIE model to avoid distorting and ripping to achieve global coverage. The global subdivision has the following advantages: the data abstractness, the integrity of topology, rapid data acquisition, multi-resolution, and good alternating browser. The STQIE establishes systematically subdivision catalogue model code of global remote sensing data, which provides the theory basis of subdivision coding system of the short message communication system based on the BD satellite system.The compression image technique of subdivision cell mainly adopts JPEG2000. The application field of JPEG2000 includes internet, color fax, printing, scanning, data production, remote sensing, mobile communication, medical image, electronic business and so on. The standard provides a set of new feature, which comprises high compression rate, lossless compression and lossy compression, general transmission, ROI compression, the random access and processing of bit stream, fault tolerance, open frame construction, and based on contents description.The dual mode positioning operated by GPS and BD satellite system is realized through the passive positioning of GPS and the initiative positioning of BD satellite system. This paper analyzing in detail the positioning principle, algorithm method, satellite orbit, coverage scope, system capacity, positioning accuracy, communication power and so on, through comparison to analyzing global positioning, BD satellite systemⅠa ndⅠ.The three main functions of BD satellite are: rapid positioning, brief communication, accurate time service. The five advantages of the BD system are time service with communication function, wide coverage in China including the region without communication, especially suitable for supervision and management of large scope for group and application of data transmission for data collector, combining BD guiding positioning system with the satellite strengthening system, the autonomous system is safe, reliable, stable, and strict confidentiality. Thus it is suitable for key department. Therefore, the exploitation for the function of the BD short message system is the key point in this paper.The embedded GIS is a new application field and the product combing the GIS with the embedded hardware. The embedded GIS provides a platform for all kinds of embedded equipments, and the embedded GIS is the branch and extension of GIS field. Integrating the production of the GIS function on the embedded system is the application on design and exploitation of system, the combining system of software and hardware, the ideal scheme that integrates the guiding, positioning, map inquiring and the management of spatial data. As the development of the embedded equipment, the embedded operation system, guiding positioning and the mobile interconnection, the embedded GIS has been applied in the economic construction and modernized national defense.The followings are what the writer have achieved in this dissertation:Based on STQIE model,it advances the partition process of remote sensing data, and processes the analysis and design of the subdivision cell coding.The subdivision cell image based on remote sensing image can be compressed through the JPEG2000 image compression technique, which lies the function for general transmission, general displaying and so on.The embedded GIS adopts GPS/BD positioning module to realize the dual module positioning. The transmission of subdivision cell image was realized through the function of the short message of the BD satellite system.. The gradual transmission and the gradually displaying were realized.The reusability is increased through developing the GIS and embedded GIS and adopting module design for main code.