GPS資訊儲存模型

Abstract

在科學研究的領域中，全球衛星定位系統(GPS)在定位及測量方面的研究已經十分的廣泛。為了使GPS 能更準確提供各項資訊，如精密星曆、衛星時差等，科學界也持續修正各項誤差以提升其精確度。此外訊號之頻段亦提供雙頻接收，其雙載波分別為L1 載波與L2 載波，頻率分別為1575.42MHz 與1227.60MHz，經由L1 與L2 載波相位的計算，可大幅提升GPS 之精度。由於此項定位功能的高精確性與方便性，使得全球衛星定位在科學用途上應用十分的廣泛，在地球科學方面如：地殼變動、海洋、火山活動等地表運動的研究，以及電離層、對流層的大氣監測等探測技術。 在GPS系統執行的過程中，天空中的衛星狀態與當時地貌可能都沒有機會重新複製，因此若能精準地記錄下當時的所有相關資訊，則在未來修正定位的演算法或改良系統將得到極大的幫助。基於此前題下，本研究將架構在全球衛星定位系統(Global Positioning System)與微算機系統上常用的非揮發性的記憶體(non-volatile memory)架構上，也就是目前市面上很普遍的商用GPS全球定位系統。但是根據不同GPS的需求，軟體資訊系統則需要實作不同的GPS資訊的儲存及使用的規則。本研究提出一個基於嵌入式系統上的一個可動態改變之GPS資訊儲存系統，上層的軟體系統僅需透過NMEA (National Marine Electronics Association)指令就能動態改變想要記錄的地理資訊或是衛星的資料。除了可攜性之外，本研究也基於儲存空間，耗電方面，提出一個更有效率的GPS資訊儲存系統模型。

In the field of scientific research, global positioning system (GPS) positioning and measurement has been studied in many aspects. To make GPS more accurate, the provided information such as precise ephemeris and satellite time difference, the research community has continued to amend the error to improve its accuracy. In addition, it also provides dual-band signal receiver, the dual-carrier were L1 and L2 carrier frequency, 1575.42MHz and 1227.60MHz, respectively. Through the phase calculation of L1 and L2 carriers, we can significantly improve the accuracy of GPS. Since the positioning function features high accuracy and convenience, it makes global positioning satellite applications for scientific purpose widely deployed for Earth science such as tectonic movement, sea, volcanic activity and other ground motion studies, ionosphere, troposphere air monitoring, and detection technology. During the execution of a GPS system, the status of a satellite in the sky and the landscape was unlikely to be reproduced, therefore, if we precisely record all relevant information at the time, then the amendment would be a great help for the future positioning algorithm or the modification of the system. Based on such premise, this study will be based on the global positioning system (Global Positioning System) and the micro-computer systems commonly used in non-volatile memory (non-volatile memory) architecture, which is very popular now on the commercial Business GPS Global Positioning System. However, according to the requirements of different GPS, software and information systems need to implement different storage and usage of GPS information rules. In this research we propose a architecture based on an embedded dynamic change of the GPS information storage systems, so that the application software could dynamically change the geographic information or satellite data to be recorded through the upper NMEA (National Marine Electronics Association) command. In addition to portability, we also proposed a more efficient information storage model of GPS based on storage space and power consumption.