七月紫梦
GPS technology in the application of modern measurement Source: China Geo-Network Authors: Gao Published: 2009.01.22 GPS performance, high precision, is by far the best navigation and positioning system. GPS measurement technology in measuring point no pass as required, to facilitate the choice of site can be a significant reduction in the construction of a high standard to save the cost of building standard, can be full-time observation, observation time is short, data-processing speed and high precision results, the full completed and development of surveying and mapping industry will lead to a profound technological revolution. GPS can be used to establish a high-precision geodetic control points and project control points. GPS using L-band, with the two carrier frequencies: L1 center frequency of 1 575.42 MHz, L2 of the center frequency of 1 227.6 MHz. There are many types of receivers, according to the required accuracy can be divided into single-frequency code rough precision dual-frequency code receiver and the receiver, the use of coarse code receiver in real-time positioning accuracy of about 25 m, precise real-time code receiver positioning accuracy better than 10 m, the use of phase receivers, data processing by the relative position (three-dimensional determination of the baseline) or parts per million accuracy, the baseline length of several kilometers from the 1 000 km, a typical baseline of 15 km of three coordinates with centimeter-level difference, the measurement time by up to several hours. 1 in urban Measurement With the acceleration of urbanization process, urban development has been greatly measurement, measurement of the outcome of the city, into a map is urban planning, construction and management of an important foundation for the necessary information, and other geodetic survey and mapping work is the basis for geodetic measurement system for a variety of topographic maps and to provide high-grade construction control points, but also for the geophysical basis to provide accurate information. Control of the city combined with measurements (or geodetic) the actual use of GPS control network technology for the establishment of cities, the expansion of great significance. At present, many cities such as Guangzhou, Shenzhen, Beijing, Shanghai and other places to explore in this area, better results are achieved. 2005, 4 to 8 months, I led in Jiangmen City, Jiangmen area control network GPS-C / D-class networks work. (1) Instrument and Equipment Company 5700 United States Trimble dual-frequency receivers 4 with a small disc antenna, equipment for a nominal accuracy of slant range (10 +2 × 10-6 mm) D, as long on the receiver, short baseline test, and compared with the standard baseline testing and other items to be seized, are up to a nominal accuracy indicator. (2) application of the operation from the beginning of April, in Jiangmen City, Xinhui, Heshan, Taishan, Kaiping, Enping six county-level cities, such as to carry out GPS measurements CITYNET more than a total of 280 points. Urban fabric of the network principle is based on the old network to expand coverage and improve the accuracy of control. Field measurement programs and data processing, according to the specific circumstances and requirements of the city by making arrangements for GPS operation group. Station, such as the number of connections to expand and, if necessary, the choice of coincidence points. Technical basis for operations, "Global Positioning System measurements norms" (GB/T18314-2001) and technical design document. Through the region based on satellite time, the development of operational plans, choose the best satellite group, in order to secure work as far as possible during the day, two hours a day observation, observation of at least six satellites can be tracked, PDOP ≤ 6 (Position Dilution of Precision Position Accuracy strong and weak degrees), each station at least two points, when the long-control in 30 to 60 minutes, while even-type expansion of the use of redundant measurements increase. (3) outside the industry and the results of the baseline pre-treatment field to choose to carry a portable computer 1, data on daily pre-treatment baseline in time, where the baseline test-retest, closed-loop overrun or ambiguity is no solution of the re - measured. The reasons are the following aspects: 1) Instrument instability, may be related to weather conditions, and have a receiver has been repaired after the 1st day where the use of the equipment can not be used on the baseline all-round and continue to improve operations; 2) the temperature is too high affect the accuracy of the results, such as a place up to a temperature of 36 ~ 38 ℃ when the outcome could not be accessed, adjusted after the observation time to resolve; 3) Lightning storm over, the phenomenon occurred many times down; 4) inaccurate measurement of antenna impact of high baseline length. Several cities through the application of results and comparison with the old coordinates, GPS positioning technology for urban control network and engineering network, with a precision, high speed, high efficiency, low cost, the results of the accuracy of the advantages of uniform and reliable. 2 in the topography, cadastral and real estate Measurement The photo shows the city terrain measurement, the mining area, as well as a variety of projects on different scales of topographic maps in order to meet a variety of urban planning and economic development needs. Cadastral surveying and real estate ownership of land is the precise determination of the location of boundary points, while surveying and mapping for land and property management departments of large-scale cadastral plan and property map, and count the amount of land and housing area. GPS there can be high-precision and rapid determination of the coordinates of control points at all levels. In particular the application of RTK (Real Time Kinematic real-time dynamic measurement) of new technologies, or even not at all control points laid only a certain number of benchmarks based on control points, will be able to measure high-precision and fast boundary points, topographic point, feature the coordinates of points, the use of mapping software can be a mapping in the field into an electronic map, and then through the computer and plotter, printer output maps of various scales. Application of RTK positioning technology for base station receiver when the request to real-time observation data (such as the pseudo-range or phase observations) and the known data (such as coordinates of the base site) real-time transmission to the mobile GPS receivers, mobile rapid solution of the whole week ambiguity in the observation that the six satellites (at least 4) after solving a real-time centimeter-level position of the mobile dynamic. This GPS static, rapid static positioning need to be processed later, the efficiency would be greatly enhanced positioning. It is a RTK emerging technology, and its application in the measurement of immediate attention. (1) RTK technology for measuring a variety of control Measurement of conventional control, such as triangulation, traversing, to claim, as the inter-pass, time-consuming and labor, and the accuracy of non-uniform, outside the industry do not know the accuracy of measurement results. GPS static, rapid static measurements do not point relative positioning between the pass, as can a variety of high-precision control and measurement, data processing and time-consuming but not real-time positioning accuracy of positioning and that they know, and found within the industry to deal with non-precision measurements require rework. Using RTK technology for control of measurement results of both real-time position to know as well as real-time positioning accuracy to know, so that operational efficiency can be greatly enhanced. RTK technology for real-time applications can achieve centimeter-level positioning accuracy, therefore, in addition to the control of high-precision measurement is static relative positioning using GPS technology, mapping the terrain of the control survey, cadastral and real estate measurement measurement and boundary control little bit of measurement can be used RTK technology. Mapping using RTK technology, only one person carrying instruments to measure in the Department of the broken point of observation on the importation of 1,2 seconds and at the same time the characteristics of coding, electronic hand-book or a portable computer records, in points in line with the requirements of accuracy Under a regional point of the terrain and surface features measured returned indoors or in the wild, by a professional surveying and mapping software can be requested by the output of the topographic map. RTK technology used does not require the determination of points between points Visibility, only one person operation, can be completed mapping work has greatly enhanced the efficiency of mapping. (2) RTK technology in the real estate cadastre and Measurement Cadastral surveying and real estate measured in RTK applications each boundary point of land ownership and cadastral mapping and real estate maps, topographic maps with the above mapping, as in real-time determination of the boundary points and a number of feature points and required to achieve centimeter-level accuracy. GPS data will be treated to obtain direct entry GPS, can be accurate and timely access to land and real estate plans. However, the impact of GPS satellite signal reception area of the shelter, you should use Total Station, range finder, theodolite and other surveying tools, the use of analytical method or graphical method for measurement details. Determined by the geological survey in the construction industry measurement, RTK technology in real-time determination of the location of boundary markers to determine the scope of land-use boundaries, the calculation area. RTK surveying the use of technology is bound coordinates directly lofting lofting and building a community determined by the geological survey in the area of measuring and calculation, in fact, by the GPS software features direct calculation of area and check. To avoid the conventional analytical method of the complexity of setting out to simplify the determination of the construction sector with the geological survey work procedures. 3 in engineering applications in deformation monitoring GPS since the mid-20th century into the 80's post-Civil, has been widely available in navigation, positioning and other applications in various fields, particularly in the measurement control surveying profession played a landmark role. It is precisely because of its relative positioning in a static high precision and high efficiency, all-weather, do not pass, as people generally used to gradually replace the conventional triangle, triangular, corner and so on, and in theory, the practice has been gratifying results. However, in precision engineering deformation monitoring applications are also rare, is still in the theoretical study and practice are explored. I will be following in GPS (works) of the base deformation monitoring design, graphic design of structural strength, the design of observing time, monitoring of the design cycle for an analysis to explore the use of GPS technology to carry out the works of new ideas for observing the deformation. 3.1 reference design Deformation monitoring in the project, the reference design (including location-scale internal and external benchmarks and reference design) is a related to monitoring the reliability of the results accurately reflect the deformation of the deformation of body work, with conventional means, of a building ( conformation) for deformation monitoring Buildings, as the apparatus and many other factors, makes the reference point network can not leave too much monitoring of regional deformation, but also by their proximity to the effects of deformation, deformation can not accurately reflect the value, Therefore, the more difficult. GPS technology as a result of the continuous improvement of the available high-precision instruments (1 +0.5 × 10-6 mm), to solve this problem easier, the benchmark can click in the deformation zone, in order to ensure the data can be reliability. 3.2 Graphic design of structural strength Graphic design refers to the strength between the deformation and deformation between the reference point with the geometry configuration, the baseline number of independent network connections and design. First of all, the selection process in the graphics, it is essential to take into account the reference point for the effective control of the deformation point, at the same time between the baseline calibration but also to each other. Secondly, in the model identification and parameter identification of the design will be able to guarantee the deformation model of the real and the real factors that caused the deformation in order to analyze the deformation caused by real factors and take appropriate countermeasures. (1) model to identify the design of model reference network in the design, it should be able to effectively network to detect any instability point; in the design of the relative network should be able to correct the deformation from several possible models of detection and separation deformation model of the real. Deformation in order to ensure the results of the analysis is correct, GPS monitoring network also need to have good gross error detection and positioning capabilities. Studies have shown that when the GPS baseline vector of each point in the network issued a number of baseline for at least three, the network has good reliability. (2) the design of model parameter identification, we can see from the above, as long as the index can be divided to meet the requirements, must meet the requirements of sensitivity, but the best deformation model parameters are often also need more precise estimate. 3.3 Observation of the design cycle time and For the observation period and the cycle can be engineering and project the nature of deformation (such as dramatic changes, for rapid changes in the slow long-term changes, etc.) combined with analysis, to make a favorable outcome for the analysis and monitoring to achieve the intention of the best observation cycle, and can be combined with the current distribution of the sky satellite, satellite state of health, for the length of time during the day, night, weather and external factors such as the various analysis, the observation period to draw the best. 3.4 for a long time observation, data processing sub-epoch - to describe the deformation displacement (horizontal) A new method of data processing Usually carried out by the relative static positioning method is the use of observation in a particular period of time (synchronous) data, such as the use of differential means, obtained with the vector between the coordinates; and for even
wuli小拧
要3000字长的文章,这里哪放得下呀?我提供的有3100字左右,下面的只是开头的部分,如果感觉合适,请提供邮箱地址。GPS global satellite positioning system and its application in the modern transportations全球卫星定位系统GPS及其在现代交通运输中的应用[Abstract: This paper describes the GPS system principles and its three sub-systems, highlighting the GPS system in the transport network applications, including road works, car navigation and traffic management and other applications] [摘要:本文系统介绍了GPS的原理和其三大子系统,着重介绍了GPS系统在交通运输中的应用,包括在道路工程、汽车导航和交通管理中的应用以及其他应用] 1, Global Positioning System GPS Overview Global Positioning System GPS is the U.S. military early 70s, "TRANSIT satellite navigation and positioning" technically replaced with the Development of global, all-round nature (land, marine, aviation and aerospace), all-weather advantage of the navigation and positioning, timing, velocimetry. GPS constituted by three major sub-systems: space satellite systems, ground control system, the user receiving system. Space Satellite System Space satellite system is composed of uniformly distributed in six orbital planes of 24 high-orbit satellites work, the orbital plane relative to the equatorial plane with an inclination of 55Ο, orbital plane spacing 60Ο. In each orbital plane, the inclination of satellite l length difference 90Ο, any track on the west side of the adjacent satellites in orbit than the corresponding satellite ahead 30Ο. In fact, the number of satellites in space satellite systems to more than 24, so that timely replacement of aging or damaged satellites, security systems work properly. The satellite system can guarantee that any one place on Earth available to users in more than four visible satellites. Space systems, each satellite at 12 hours (sidereal time) along nearly circular orbits around the globe, from space-borne high-precision atomic clocks (the base frequency F = 10.23MHZ) control the radio transmitter in the "low-noise window" (Radio window , the frequency range of 2 to 8 the minimum noise section of the antenna area of space remote sensing and radio interferometry preferred band) near the launch of L1, L2 two kinds of carrier receiving system to global users of GPS navigation signals continuously broadcast. The working Group on GPS satellite network to protect the world at any one time, any place can be of four or more satellites for observation (up to 11), to achieve continuous, real-time navigation and positioning. 一、全球定位系统GPS简介 全球卫星定位系统GPS是美军70年代初在“子午仪卫星导航定位”技术上发展而起的具有全球性、全能性(陆地、海洋、航空与航天)、全天候性优势的导航定位、定时、测速系统。GPS由三大子系统构成:空间卫星系统、地面监控系统、用户接收系统。空间卫星系统 空间卫星系统由均匀分布在6个轨道平面上的24颗高轨道工作卫星构成,各轨道平面相对于赤道平面的倾角为55Ο,轨道平面间距60Ο。在每一轨道平面内,各卫星升交角距差90Ο,任一轨道上的卫星比西边相邻轨道上的相应卫星超前30Ο。事实上,空间卫星系统的卫星数量要超过24颗,以便及时更换老化或损坏的卫星,保障系统正常工作。该卫星系统能够保证在地球的任一地点向使用者提供4颗以上可视卫星。空间系统的每颗卫星每12小时(恒星时)沿近圆形轨道绕地球一周,由星载高精度原子钟(基频F=10.23MHZ)控制无线电发射机在“低噪音窗口”(无线电窗口中,2至8区间的频区天线噪声最低的一段是空间遥测及射电干涉测量优先选用频段)附近发射L1、L2两种载波,向全球的用户接收系统连续地播发GPS导航信号。GPS工作卫星组网保障全球任一时刻、任一地点都可对4颗以上的卫星进行观测(最多可达11颗),实现连续、实时地导航和定位。问题补充:已发到您的QQ信箱,请查收。【英语牛人团】
很多时候会想起
GPS接收机是位于地球上的用户测定所在位置经度、纬度和高程的设备,一台接收机是通过测量四颗或四颗以上卫星的无线电信号传输到用户位置所用时间来计算每个卫星到用户所在位置的距离,从从而进一步确定经度、纬度和高程的。美国国防部最初是出于军事目的开始对导航星系统的研发,但是全球的普通用户已经可以免费使用较低精度的接收设备了。一般用户设备的定位精度可以达到10米(33英尺),通过不财的技术手段可以将定位精度提高到1厘米(0.4英寸)以内。由于这种设备的精度和全天候特性,GPS的应用已经远远超出军事用途,在个人与商务导航领域引发了一场新的革命。战术导弹和巡航炮使用GPS信号测量它们的位置和速度,在美国的航天飞机、太空站也和商用喷气机、私人飞机一样使用该系统测量位置和速度。救援船、私家车、铁路运输等也象农场的拖拉机、跨越大洋的航班、徒步旅行都甚至是打高尔夫球的人也都受益于GPS定位。GPS的主机芯片只有婴儿的指甲那样的大小,所以可以装在手表、移动电话和个人数码助理里,所以许多GPS接收机比袖珍计算器还小,并且可以由一次性电池提供能量。
仗剑拂衣去
GPS1. SpaceThe space is part of GPS satellite by 24 work [1], it is located above the surface of the 20 200km, evenly distributed in six track surface (4) each track surface, orbit for 55 ° Angle. In addition, there are four star orbiting satellites active backup. The distribution of satellite in global anywhere at any time can be observed in 4 above, and can keep good satellite positioning accuracy of geometrical image solution. This provides a continuous on time in the global navigation skills. GPS satellite produces two groups, one group called Morse code (C/A Coarse/Acquisition Code11023MHz), A group called the P (Procise Code 10123MHz), P Code for higher frequency, not suffer interference, high precision, so by the U.S. military control, and the password, generally, mainly for folk cannot U.S. military service. C/A code for measures to lower accuracy, and deliberately used mainly open to folk.2. The ground controlThe ground control station by a master, five global stations and 3 ground control station. There are equipped with precision of the station clock and continuous measuring cesium visible satellites to accept machine. The satellite observation stations will obtain data, including the ionosphere and meteorological data, after initial treatment, to master station. Master station from various stations, satellite tracking data calculated the orbit and clock parameters, then will result to 3 ground control station. The ground control station in each satellite run over to the navigation, master station instructions and data into a satellite. The injection of each star GPS satellite, and in every time inject stood range from satellite before finally injection. If a ground fault, so in the satellite navigation of stored information can also be used for a period of time, but the navigation precision will gradually decrease.3. User equipment partsUser equipment parts namely GPS signal receiver. Its main function is to capture by certain Angle of satellite deadline to choose to follow these satellites and satellite, the operation. When the receiver to capture the satellite tracking, after receiving antenna can be measured and satellite pseudo distance and the distance change, satellite orbits parameters, such as the demodulation data. Based on these data, the receiver can handle the computer by positioning solution method and computing the user's position in the longitude and altitude geographical position, speed, time, etc. The hardware and software receivers in GPS data post-processing software package and form a complete GPS user equipment. GPS receiver unit and receiving antenna structure is divided into two parts of the unit. Receiver generally USES machine and together two kinds of dc power supply. Setting machine aims to replace the power supply without interruption continuous observation. In use within the time machine power battery charging automatically. After shutdown, machine battery power for the RAM, memory, in order to prevent the loss of data. At present various types of accept machine, weight and small volume and light, facilitate the field observation.The Ground control system (by now), the Station so the control Station (Master), so now the Antenna (Ground), the Antenna control Station, colo springfield, Colorado (are). The ground control station is responsible for collecting information by satellite, and alex, relative to star satellite data from the atmosphere correction. Secondly, the existing users receiver for two and two, double-frequency due to price factor, general user buys more for single-rate receiver.Aiming at the application of GPS road engineeringThe application of GPS in road construction, is mainly used to establish various road engineering control network and determination of the control points electricity, etc. Along with the rapid development of the highway to survey technology, puts forward a higher request, due to long, known points less, therefore, with the conventional measure method not only, and the net difficulties are hard to meet the requirement of high precision. At present, China has gradually establish lines using GPS technology, then head high precision control network layont wires with conventional methods. Practice has proved, in a few tens of kilometers within the scope of the point error only 2 centimeters, reached the conventional method to realize the accuracy, but also greatly ahead of time. GPS technology also applied to the control measure of large bridge. Since it is unnecessary to tong, can form strong nets, improve accuracy of inspection, via conventional measure fulcrum is effective. GPS technology in the measurement of the tunnel has broad prospect of application, GPS, reduced need through conventional method, the intermediate links, therefore, high speed, high accuracy, significant economic and social benefits.A GPS navigation and traffic management in automotive applicationsThree-dimensional navigation is the primary function, GPS, ships, aircraft and ground vehicles pacers can use GPS navigation device for navigation. Car navigation system is in the global positioning system (GPS developed on the basis of a new technology. Car navigation system by GPS navigation, self-discipline, navigation and microprocessor, speed sensor, gyro sensor and cd-rom drives, LCD display. GPS navigation systems and electronic map, radio communication network, computer vehicle management information system, combining can achieve vehicle tracking and traffic management and many other functions.A GPS in long-distance passenger vehicle management application (for example),In the first set of professional long-haul GPS vehicle management system, and long-distance communication GPS intelligent management system, for example, it is combined with the satellite positioning technology, GPRS/CDMA communications business, GIS, image collection technology, computer network technology, and database in the company to build a passenger control (C/S structure and B/S structure combining), and the other for points, the public security bureau and control YunGuan departments and departments of the control system, established by the control center system, wireless communication system platform (GPRS/CDMA), global positioning system (GPS), four parts and trackside equipment all-weather, a full range of driver and vehicle tracking management platform, System can be registered vehicle dynamic tracking and monitoring implementation, pictures, driving record, management, data analysis and so on the function, monitoring vehicles in electronic map, and display of vehicles running track data, Operating terminal optional internal network or the Internet server to visit and through the center to provide online IE browser integrated passenger management data analysis of the control system (B/S structure), And the capacity of the system software available according to the center of the hardware configuration and operating terminal server, the most greatly expanded, net vehicles 500,000 can not only is long, can the passenger vehicles such social vehicles. And the system still can use group management, different types of vehicles into different groups, facilitate the operation management.GPS technology application examples in the navigatorGPS navigators international leading brand: Ahada YiHang (of) -- from silicon valley, now login China!The core products function:1) map queryA penny saved is a penny gained in operation on a terminal search your destination location.A penny saved is a penny gained can record you always want to place, and retain information, also can be Shared with others and the location information.A penny saved is a penny gained fuzzy query your attachment or a location near the station, hotel, such as ATM.2) route planningA penny saved is a penny gained GPS navigation system will be set according to the starting point and destination, automatic programming line.A penny saved is a penny gained planning routes whether can be set to pass some ways.A penny saved is a penny gained planning routes whether can avoid high-speed etc. Function.3) automatic navigationA penny saved is a penny gained speech navigation:To provide drivers advance in speech, navigation condition intersection traffic information, such as a way to understand the wizard tells you how to drive to the destination. Navigation in one of the most important function, make you need, through watching operation terminal voice prompt can safe destination.A penny saved is a penny gained picture navigation:In the end, will display operate maps and position of the car now, driving speed, the destination of the route, planning, crossing the road to tip.A penny saved is a penny gained redesign line:When you have the line planning, or go wrong when crossing, GPS navigation system according to your present position, for you to plan a new route to the destination.GPS principleGPS navigation system is the basic principle of measuring the satellite to known position of the distance between the user receiver, and then integrated satellite data can know the location of the receiver. To achieve this objective, the position of the satellite can according to record the clock time on satellite star found in a calendar. Visible GPS navigation system is part of the satellite launch navigation ceaselessly. However, due to the use of the user to accept machine with satellite space-borne clock clock synchronization, may not always except user 3d coordinate x, y, z, will also introduce a Δ t is the difference between the satellite and the receiver as unknown, then use four equations will these four unknown. So if you want to know, the receiver's place at least four satellites can receive the signal.GPS receiver can receive the GPS clock can be used to accurately on the two levels of second time information, Used to forecast the next few months in the general position of satellite prediction star alex, Can be used to calculate the location for the satellite radio star alex, the coordinates for a few meters to dozens of accuracy of each different, rice (change) satellite, And the GPS system information, such as satellite.GPS receiver to code measurement can get satellite receiver, because of the distance to the clock contains receiver satellite transmission error, error and the atmosphere is called pseudorange. 0A yards of measured pseudorange called UA yards pseudorange and accuracy for about 20 meters of P yards, measured pseudorange called P yards pseudorange and accuracy for about 2 meters.GPS receiver of received signal, decoding technology, or other information on the carrier modulation in removed, can restore carrier. Strictly speaking, the carrier phase should be called the carrier frequency phase, it is patted the received by doppler frequency influence of satellite signal receiver carrier phase and machine generated signal phase difference oscillations. General bell in the epoch receiver determined to keep time measurement, satellite signal, it can track record of phase change, but start when the value of the receiver and satellite observations of the oscillator is not know the initial phase of the epoch, also don't know phase integers, namely the fuzzy degrees, only in data processing as parameters. Phase observations of high precision and mm, but the premise is a whole week, so only in fuzzy relative positioning, and a continuous observation can use phase observations, and to achieve superior level meters positioning accuracy of also only using phase observations.According to the localization way, GPS positioning and relative into single point positioning (difference). According to a single point positioning receiver is the observation data to determine the position of the receiver, it only USES pseudorange observation, can be used as a compendium of navigation and positioning vehicles. Relative location (difference) is based on the observation data of two above receiver to determine the relative position between the observation methods, it can be adopted pseudorange observation may adopt phase observation and geodesy or engineering measurement shall be made phase observation value relative positioning.In the GPS observation satellite and the receiver is contained in the clock, atmospheric propagation delay, the multipath effect etc, in the positioning error when calculating by satellite radio star alex, the influence of error in relative positioning error when most public offset or weakened by positioning accuracy, so will greatly improve, double-frequency receiver can according to the observation of two frequency offset the atmosphere, the main part of the error of the ionosphere, high accuracy in the distance between the receiver when significant difference (air), should choose double-frequency receiver.
是的,一般都是要翻译的了。
因为刚翻译完心有所感。。。必须得翻译过来,并且要严格按照原文的图表对译。前两周我们就是为了这个纠结的要命,毕竟PS也不是很熟练,于是就先用QQ截图,把大小先控制
外文文献,就是你毕业论文中所参考到的外国相关文献。不一定要原文引用,比如你采纳了其中一个论点,或者论据都行,总的来说就是参考文献,你引用也好借鉴也好,都行。
GPS technology in the application of modern measurement Source: China Geo-Networ
毕业论文用英语的翻译:毕业 论文 迅捷在线翻译:Graduation (毕业) thesis(论文)参考一下