【正文】 the project layout, the terrain mapping, each kind of control survey has brought the new dawn, enormously enhanced the field operation work efficiency. The high accuracy GPS survey must use the carrier phase observation value,the RTK localization technology, it can realtime provide in assigns in the coordinate system the three dimensional localization result, and achieves the centimeter level precision. Under the RTK work pattern, the datum stands through the data chain transmi ts together its observation value and the survey station coordinates information for the mobile station. Mobile stands not only receives the data through the data link which stands from the datum, but also must gather the GPS observation data, and poses the difference observation value in the system to carryon the realtime processing, simultaneously produces the centimeter level localization result, a lasted. The mobile station may be at the static condition, also may be at the state of motion。但由于多普勒衛(wèi)星軌道高度低、信號載波頻率低，軌道精度難以提高，使得定位精度較低，以滿足大量測量或工程測量的要求，更不能用于天文地球動力學研究。對于測繪界的用戶而言，GPS己在測繪領域引起了革命性的變化，目前，范圍上數(shù)公里至幾千公里的控制網(wǎng)或變形監(jiān)測網(wǎng)，精度上從幾百至毫米級的定位，一般都將GPS作為首選手段，隨著RTK 技術的日趨成熟，GPS一開始向分米乃至厘米級的放樣、高精度動態(tài)定位等領域滲透。GPS接收機對收到的衛(wèi)星信號，進行解碼或采用其它技術，將調(diào)制在載波上的信息去掉后，就可以恢復載波。在定位觀測時，若接收機相對于地球表面運動，則稱為動態(tài)定位，如用于車船等粗略導航定位的精度為30100 米的偽距單點定位，或用于城市車輛導航定位的米級精度的偽距差分定位，或用于測量放樣等的厘米級的相位差分定位(RTK)，實時差分定位需要數(shù)據(jù)連降兩個或多個站的觀測數(shù)據(jù)實時傳輸?shù)揭黄鹩嬎??？稍诠潭c上進行初始化后再進入動態(tài)作業(yè)，也可在動態(tài)條件下直接開機，并在動態(tài)環(huán)境下完成周模糊度的搜索求解。軍用GPS產(chǎn)品主要用來確定并跟蹤在野外行進中的士兵和裝備的坐標，給海中的軍艦導航，為軍用飛機提供位置和導航信息等。(2)多元化空間資源環(huán)境的出現(xiàn)目前，GPS，GLONASS，INMARSAT等系統(tǒng)都具備了導航定位功能，形成了多元化的空間資源環(huán)境。為發(fā)展我國的GPS產(chǎn)業(yè)，武漢已經(jīng)成立中國GPS工程中心?？傊?，由于多元化空間資源環(huán)境的確立，給GPS的發(fā)展應用創(chuàng)造了一個前所未有的良好的國際環(huán)境。用于監(jiān)測地球板塊運動狀態(tài)和地殼形變:用于工程測量，成為建立城市與工程控制網(wǎng)的主要手段。如果把RTK用于公路控制測量、電子線路控制測量、水利工程控制測量、大地測量、則不僅可以大大減少人力強度、節(jié)省費用，而且大大提高工作效率，測一個控制點在幾分鐘甚至于幾秒鐘內(nèi)就可完成。高精度的GPS測量必須采用載波相位觀測值，RTK 定位技術就是基于載波相位觀測值的實時動態(tài)定位技術，它能夠?qū)崟r地提供測站點在指定坐標系中的三維定位結果，并達到厘米級精度。按定位方式， GPS定位分為單點定位和相對定位(差分定位)。GPS定位原理GPS 接收機可接收到可用于授時的準確至納秒級的時間信息，用于預報未來幾個月內(nèi)衛(wèi)星所處概略位置的預報星歷:用于計算定位時所需衛(wèi)星坐標的廣播星歷，精度為幾米至幾十米(各個衛(wèi)星不同，隨時變化)。GPS 系統(tǒng)的控制部分有設在美國本上的5個監(jiān)控站組成，這些站間不斷地GPS衛(wèi)星進行觀測，并將計算和預報的信息由注入站對衛(wèi)星信息更新。Used in project measure,is it set up city and project control main means of network to bee For determine AeroSpace photograph camera position in the twinkling of an eye, realize for a small amount of ground control or there is no aerial survey controlled in region to bee and pursue fast, technical revolution causing the geographical information system,global environmental remote to follow their lot of merce and government organs use GPS equipment to follow their vehicle position。 s quantity also is not limited. Although GPS is the unification starts is, but very quantity also is not limited. Although GPS recei ver and processing software emerge in abundance. At present the receiver which appears in the Chinese market mainly has ROGUE,ASHTECH, TRIMBLE, LEICA, SOKKIA, TOPCON and so on.. Can carry on the observation to two frequencies the receiver to be called the double frequency receiver, only can carryon the observation to a frequency the receiver to bee the inference. Says regarding the mapping user, GPS has caused the revolutionary change in the mapping domain, at present, in the scope several thousand kilometers controls network, in the precision from hundred to the millimeter level localization, generally all GPS took the first choice method, is day by day mature along wi th the RTK technology, GPS started to decimeter and even a centimeter level layout, domain seepage and so on high accuracy dynamic localization. The international GPS geodetic survey served IGS with Earth dynamics from 1992, has established many data storage and the processing center in the whole world, year to year observed a station with hundred, our country has also set up Shanghai Yu Shan, Wuhan, Xian, Taiwan and so on many year to year measuring platforms station, these stations observation data passed on every day through the internet net to US39。 May first carryon the initialization after the fixed point to enter the dynamic work again, also may under the dynamic condition directly opening machine,and pletes the week fuzziness search solution under the dynamic environment. After end knows the number solution to be fixed, then carries on each calendar Yuan realtime processing, so long as can maintain four above satellites phases observation value the track and the essential geometric figure ,then the mobile station may produce the centimeter level localization result as necessary.The RTK technology key lies in the data processing technology and the data transmission technology, when the RTK localization requests the datum station receiver realtime the observation data (false distance observation value, phase observation value) and the know data transmission for the mobile station receive, the data quantity quite big, generally all requests 9,600 bauds rate, this in on radio is not difficult to realize.4. The application of RTK(1) Each kind of control surveyThe traditional geodetic survey, the project control survey uses the triangular net, the linenetwork method executes measured, not only requires a lot of work timeconsuming, request Indivisibility, moreover the precision distribution nonuniformity