【正文】 ，花費(fèi)的代價(jià)大，隨著時(shí)間的推移，大量點(diǎn)位遭到破壞，使傳統(tǒng)的工程控制測(cè)量難以實(shí)施，且施測(cè)過(guò)程中還必須考慮通視條件和圖形結(jié)構(gòu)，使工程測(cè)量的精度和效率受到很大影響。 研究背景與意義 傳統(tǒng)的工程控制測(cè)量是在大地測(cè)量基礎(chǔ)上進(jìn)行的，即必須有一定數(shù)量的已知點(diǎn)作為工程控制測(cè)量的起算依據(jù)。該系統(tǒng)可提供全天 24小時(shí)的全球定位服務(wù)，利用導(dǎo)航衛(wèi)星發(fā)射信號(hào)進(jìn)行測(cè)時(shí)測(cè)距，具有海、陸、空全方位實(shí)時(shí)三維導(dǎo)航定位能力，可為用戶提供高精度的三維位置、三維速度、一維時(shí)間信息 [3]。到 1994年，所有 GPS星座裝配完成， 20年，耗資近300億美元，最終建成由 24顆衛(wèi)星構(gòu)成的 GPS 系統(tǒng) [2]。鑒于上述原因， 美國(guó)國(guó)防部于 1973年批準(zhǔn)陸、海、空三軍共同研制第二代衛(wèi)星導(dǎo)航定位系統(tǒng)，英文為 Navigation Sstellite Timing And Ranging/Global Positioning System[1]，簡(jiǎn)稱 GPS。但由于該系統(tǒng)衛(wèi)星少，觀測(cè)間隔時(shí)間大（每隔 1~2小時(shí)才能觀測(cè)一次），無(wú)法實(shí)時(shí)連續(xù)定位，并且只能得到二維坐標(biāo)經(jīng)度和緯度，沒有高程。 關(guān)鍵詞 ： GPS 測(cè)量 精度 ； 影響因素 ； 誤差 ； 起算點(diǎn) ABSTRACT 如何提高 GPS 在工程測(cè)量應(yīng)用中的精度 1 High tech GPS as a kind of positioning technology of twentieth Century , has been widely used in ships, aircraft and vehicles’ navigation and positioning. Because of the advantages of the traditional measurement can’t be replaced by the GPS measurement, the measurement of GPS in the project measurement is being more and more important, the technical knowledge relevant also develops very quickly. With the improvement of GPS receivers,GPS positioning technology, the development of differential DGPS positioning technology and RTK realtime differential positioning technology, and meeting the dynamic, fast, high precision positioning,GPS is highly popularized and applied in land navigation, all kinds of control work establishment, precise engineering surveying, construction layout etc. With the continuous development of GPS technology and its application in the measurement being widely used, the measuring accuracy is increasingly demanded. This paper first analyzes the status quo and development research, introduces the GPS system position and measurement principle. In the analysis of the various methods of measuring, the thesis points out their advantages and disadvantages as well as the applicable conditions, the scope of use. Then analyzes the effects of various sources of error, the starting point, work design, observation time on GPS observation precision , puts forward the corresponding reduction or elimination method for a variety of errors, discusses the influence of the starting point of elevation accuracy bined with engineering example, and at last summarizes some conclusions for practical engineering. The final analysis of the factors affecting the accuracy of RTK measurement is discussed, and points out some methods to improve the accuracy of useful, and suggestions for further research are put forward to improve the accuracy of GPS measurements in engineering applications. Keywords： GPS measurement accuracy； influence factors； error； starting point 目錄 1 1 緒論 ............................................................................................................................................... 5 概述 ................................................................................................................................ 5 研究背景與意義 ............................................................................................................... 5 國(guó)內(nèi)外研究現(xiàn)狀 ............................................................................................................... 6 本文內(nèi)容安排 ................................................................................................................... 7 2 GPS測(cè)量原理及其技術(shù)概述 ........................................................................................................ 8 GPS在工程測(cè)量中的應(yīng)用現(xiàn)狀及發(fā) 展前景 .................................................................... 8 ........................................................................................................................... 8 GPS測(cè)量原理 .................................................................................................................. 10 絕對(duì)定位原理 ..................................................................................................... 10 相對(duì)定位原理 ..................................................................................................... 11 差分 GPS定位原理 ............................................................................................. 12 3 影響 GPS測(cè)量精度的因素 .......................................................................................................... 13 GPS測(cè)量誤差 .................................................................................................................. 13 與衛(wèi)星有關(guān)的誤差 ............................................................................................. 14 與傳播路徑有關(guān)的誤差 ..................................................................................... 15 與接收設(shè)備有關(guān)的誤差 ..................................................................................... 16 GPS布網(wǎng)方案 .................................................................................................................. 17 起算點(diǎn)影響因素 ................................................................................................. 17 GPS布網(wǎng)方案 ...................................................................................................... 23 觀測(cè)時(shí)長(zhǎng) ............................................................................................................. 25 4 RTK測(cè)量 ..................................................................................................................................... 26 ........................................................................................................................... 26 RTK系統(tǒng)組成 .................................................................................................................. 26 RTK網(wǎng) ............................................................................................................................. 27 RTK精度影響因素 .......................................................................................................... 27 RTK 定位誤差 ...........................................................