《毕业论文（设计）-堤防除险加固测量工程中水下测量方法初探30601.doc》由会员分享，可在线阅读，更多相关《毕业论文（设计）-堤防除险加固测量工程中水下测量方法初探30601.doc（9页珍藏版）》请在三一文库上搜索。
1、专业好文档堤防除险加固测量工程中水下测量方法初探吴定邦 （江西省水利规划设计院 江西 南昌330029）摘 要 本文结合工程实践，简要论述了单频GPS RTD和双频GPS RTK技术在堤防除险加固工中水下地形测量的应用方法，比较了两种动态定位技术在水下测量的不同，提出了如何加强精度、提高工效的应对措施。关键词 水下测量 RTD RTK 应用 措施1概述测绘信息网http:/ 随着国家对水利建设项目的不断投入，水利建设项目将越来越多，而堤防除险加固工程项目水下测量又是不可缺少的一部分基础性工作。如何提高水下测量的精度和速度，降低工程成本则是水下测量须解决的问题。常规测量水深的方法是将测深杆、测深
2、绳或测深仪安置于船头，一工作人员在船头司尺，并且将测得的水深数据通过对讲机传给岸上施测的工作人员。同时，岸上施测的工作人员采用小平板测图的方法，分工合作，标定出测量船的方向和距离，然后求出测得的水位数据与测深数据之差，即为该地形点的高程，再绘出等深线。这样工作量大，内业处理复杂，作业人员多，精度低，作业时间长。这种方法只适应于水深浅且流速不大、底质较硬条件的浅水区。对于水深较深、流速较大的作业区则采用GPS动态定位技术配合数字化测深仪可以大大提高测量精度、提高工作效率。GPS实时动态定位技术包括实时相位差分测量RTK(Real-Time Kinematic)测量技术和实时伪距差分测量RTD(
3、Real-Time Dist) 技术。2GPS实时动态定位技术2.1 RTD GPS技术测绘信息网http:/ Real-Time Dist)测量技术是以测码伪距观测量为根据的实时差分GPS测量技术。它是使用两台接收机分别置于两个测站上，其中一个测站是已知的基准点，称为基准接收机，另一台安设于运动载体上，称为动态接收机。两台接收机同时测量来自相同GPS卫星的导航定位信号。基准接收机所测得的三维位置与该点已知值进行比较，可以获得GPS定位数据的改正值，据此来改正动态接收机所测得的实时位置。它是测量技术与数据传输相结合而构成的测量系统。差分技术的关键是数据链，传输的数据量很大，对数据链质量要求特别
4、高，比实时相位差分RTK传输距离长，不容易被干扰和失锁，用户和基准站之间的距离对精度有决定性影响。RTD的重要技术是测码伪距和快速模糊度的解算。2.2 RTK GPS技术载波相位差分技术又称为RTK（RealTimeKinematic）技术，是建立在实时处理两个测站的载波相位基础上的。它能实时提供观测点的三维坐标，并达到厘米级的高精度。 与伪距差分原理相同，由基准站通过数据链实时将其载波观测量及站坐标信息一同传送给用户站。用户站接收GPS卫星的载波相位与来自基准站的载波相位，并组成相位差分观 测值进行实时处理，能实时给出厘米级的定位结果。测绘信息网http:/ 实现载波相位差分GPS的方法分为
5、两类：修正法和差分法。前者与伪距差分相同，基准站将载波相位修正量发送给用户站，以改正其载波相位，然后求解坐标。后者将基准站采集的载波相位发送给用户进行求差解算坐标。前者为准RTK技术，后者为真正的RTK技术。3RTD、RTK GPS技术在永和堤除险加固工程中的应用3.1工程概况永和堤除险加固工程位于吉安市上游赣江西岸与和水交汇处，堤线全长约21km。其中赣江西堤约19km，和水右堤约2km。属吉安县永和、凤凰两镇所辖，堤顶可通行汽车，交通较为方便。圩堤边上有部分村庄，测区树木不多通视良好。本项目水下测量至赣江深泓线，平均水深7-8米。3.2外业测量 测绘信息网http:/ 数字化测深仪方法，同
6、步记录观测值。求出水下点的高程，这种方法精度高，作业强度低，效率高，工作人员少，作业时间短。本工程项目分别以单频leica 500 GPS作RTD水下测量和用南方测绘公司的双频灵锐RTK S82作水下测量进行比较。数据采集之前，先将基准站和流动站设置好，包括计划线的生成，坐标转换和椭球参数的输入，初始设置等。1,单频leica 500型GPS设置如下：基站设置 Model: 选择RTD-REF(reference 参考站)，选择已输入经纬度的已知点号。流动站设置 Model: 选择 RTD-ROV（流动站），运行时不要选“OCUPY”。注意：测量时要观察GPS接受机电量是否够用，发射箭头是否在
7、动，水深、实时坐标数据是否正常。2,数字化测深仪设置如下图。测绘信息网http:/ 图（一）3,中海达导航软件设置如下图。 图（二）转换参数的设置是利用已知GPS控制点北京54坐标和WGS84坐标三维相匹配，通过计算所得。4,计划线布设测绘信息网http:/ 测区范围较大时，应布设计划线，目的是进行外业采集数据导航，这样有利于流动站运动时尽量减少重复运行线路，有利于采集的水下地形点分布均匀。水域测量要求每条测线垂直于主航道线，测线的行距和间距根据测图比例确定。测线按河道的走向分段布设，根据实际情况，船在航行的过程中，有方向易变的特点，即测线的行距不易控制，故在沿着河道方向完成之后，可以再沿着航
8、道布设“S”形方向，以弥补测点不够的地方。5,数据采集进行水下地形数据的采集时，我们采用了广洲南方测绘仪器公司的NGD-80测量导航处理系统。首先设置一台GPS接收机为参考站，另一台GPS接收机，数字化测深仪，计算机相连设置在测量船上作为流动站，实时解算出测量船上流动站位置的坐标，并且导航，同步测量水深数据，自动记录在计算机内，采集数据示意图如下。校正接收器导航处理器 动态用户中海达数字化测深仪差分解 动态接收机NGD80导航处理软件 计算机GPS卫星棱镜全站仪 实时水位监测基准接收机校正发射器校正处理器基准站数据基准站 图 （三）3.3内业处理 外业采集到的数据要经过水位改正，声速改正，和动
9、态吃水改正等系列处理。在内业处理时，使用了两套软件，（广州南方公司S-CASS3.0海洋成图软件，南方测绘CASS6.0测图系统）结合处理。测绘信息网http:/ RTK与RTD影响测量精度因素分析比较项目作业方法RTKRTDGps型号与标称精度南方灵锐S82 RTK 标称精度:10mm+1ppmLeiCa 500型 单频 多通道标称精度:5-10mm+1ppmGps数据1，基线解算误差2，流动站与基准站无差分引起的假数（内业成图软件删除）3，导航软件的时间延迟4，流动站标杆晃动误差5，野外观测数据粗差剔除1，基线解算误差2，导航软件的时间延迟3，流动站标杆晃动误差4，野外观测数据粗差剔除测深
10、仪1， 深仪的测深精度2，声速值的设定影响测深精度（测量前根据水温，查声速表再设定声速值）3，气泡、波浪引起的假数（设定量化盲区测深无效区、内业成图软件删除）4，测深仪吃水改正数5，野外测深数据是否平滑1，测深仪的测深精度2，声速值的设定影响测深精度（测量前根据水温，查声速表再设定声速值）3，气泡、波浪引起的假数（设定量化盲区测深无效区、内业成图软件删除）4，测深仪吃水改正数5，野外测深数据是否平滑测量船1， 测量船工作中两侧摇摆2，测量船航行时未能安要求航行2， 测量船工作中两侧摇摆2，测量船航行时未能安要求航行成果精度定位精度高定位精度低表（一）4RTD、RTK GPS技术水下测量的特点4
11、.1水下测量中的优点(1)定位精度高，数据可靠，没有误差积累。只要满足RTK的基本工作条件，在一定的作业半径范围内（一般为6km），RTK的平面精度能达到厘米级，完全可以满足一般工程测量的精度。(2)生产效率高，降低了工程费用成本，节约了工作时间。在一般的地形条件下，高质量的RTK设站一次即可测完10km半径内测区的点位测量，大大减少了传统测量所需的控制点数量和测量仪器的“搬站”次数。在一般的电磁波环境下几秒钟即可获得一组移动站的坐标，作业速度快，劳动强度低，节省了外业费用，提高了劳动效率。 (3)RTK作业自动化、集成化程度高，操作简便，容易使用，数据处理能力强，测绘功能强大。移动站利用其控
12、制器内装备的软件控制系统，无须人工干预便可自动实现多种测绘功能，使辅助测量工作极大减少，减少人为误差，保证了作业精度。(4) 作业条件要求低，和传统测量相比，RTK技术受通视条件、能见度、气候、季节等因素的影响和限制较小，在传统测量看来由于地形复杂、地物障碍而造成的困难通视地区，只要满足RTK的基本工作条件，便能轻松地进行快速的高精度定位作业，使测量工作变得更轻松、更容易。4.2水下测量的不足及其应对措施(1)数据链传输受干扰和限制、作业半径比标称距离小。RTK数据链传输易受到障碍物如高大山体、高大建筑物和各种高频信号源的干扰，在传输过程中衰减严重，严重影响作业精度和作业半径。在地形起伏，高差
13、较大的山区和城镇密楼区数据链传输信号受到限制，另外，当RTK作业半径超过一定距离（一般为几公里，每种机型在不同的环境又各不相同）时，测量结果误差就会超限，所以RTK的实际作业有效半径比其标称半径要小很多，解决有效办法是把基准站布设在测区中央的最高点上，另外作业半径最好不要超过标称距离的三分之二。测绘信息网http:/ (6)每日测深仪工作前必须进行检查，尽量避免因测深仪的各项改正而引起的误差。为进行实时水位测定，还应测量测深仪吃水深值，可以认为换能器底面至水面距离为一常数。5结束语测绘信息网http:/ 张凤举， “GPS”定位技术，煤炭工业出版社，1997.2 杨帆等，GPS-RTK在航道测
14、量中的应用初探，测绘通报，2001，（2）.Editors note: Judson Jones is a meteorologist, journalist and photographer. He has freelanced with CNN for four years, covering severe weather from tornadoes to typhoons. Follow him on Twitter: jnjonesjr (CNN) - I will always wonder what it was like to huddle around a shortwave
15、 radio and through the crackling static from space hear the faint beeps of the worlds first satellite - Sputnik. I also missed watching Neil Armstrong step foot on the moon and the first space shuttle take off for the stars. Those events were way before my time.As a kid, I was fascinated with what g
16、oes on in the sky, and when NASA pulled the plug on the shuttle program I was heartbroken. Yet the privatized space race has renewed my childhood dreams to reach for the stars.As a meteorologist, Ive still seen many important weather and space events, but right now, if you were sitting next to me, y
17、oud hear my foot tapping rapidly under my desk. Im anxious for the next one: a space capsule hanging from a crane in the New Mexico desert.Its like the set for a George Lucas movie floating to the edge of space.You and I will have the chance to watch a man take a leap into an unimaginable free fall
18、from the edge of space - live.The (lack of) air up there Watch man jump from 96,000 feet Tuesday, I sat at work glued to the live stream of the Red Bull Stratos Mission. I watched the balloons positioned at different altitudes in the sky to test the winds, knowing that if they would just line up in
19、a vertical straight line we would be go for launch.I feel this mission was created for me because I am also a journalist and a photographer, but above all I live for taking a leap of faith - the feeling of pushing the envelope into uncharted territory.The guy who is going to do this, Felix Baumgartn
20、er, must have that same feeling, at a level I will never reach. However, it did not stop me from feeling his pain when a gust of swirling wind kicked up and twisted the partially filled balloon that would take him to the upper end of our atmosphere. As soon as the 40-acre balloon, with skin no thick
21、er than a dry cleaning bag, scraped the ground I knew it was over.How claustrophobia almost grounded supersonic skydiverWith each twist, you could see the wrinkles of disappointment on the face of the current record holder and capcom (capsule communications), Col. Joe Kittinger. He hung his head low
22、 in mission control as he told Baumgartner the disappointing news: Mission aborted.The supersonic descent could happen as early as Sunday.The weather plays an important role in this mission. Starting at the ground, conditions have to be very calm - winds less than 2 mph, with no precipitation or hum
23、idity and limited cloud cover. The balloon, with capsule attached, will move through the lower level of the atmosphere (the troposphere) where our day-to-day weather lives. It will climb higher than the tip of Mount Everest (5.5 miles/8.85 kilometers), drifting even higher than the cruising altitude
24、 of commercial airliners (5.6 miles/9.17 kilometers) and into the stratosphere. As he crosses the boundary layer (called the tropopause), he can expect a lot of turbulence.The balloon will slowly drift to the edge of space at 120,000 feet (22.7 miles/36.53 kilometers). Here, Fearless Felix will uncl
25、ip. He will roll back the door.Then, I would assume, he will slowly step out onto something resembling an Olympic diving platform.Below, the Earth becomes the concrete bottom of a swimming pool that he wants to land on, but not too hard. Still, hell be traveling fast, so despite the distance, it wil
26、l not be like diving into the deep end of a pool. It will be like he is diving into the shallow end.Skydiver preps for the big jumpWhen he jumps, he is expected to reach the speed of sound - 690 mph (1,110 kph) - in less than 40 seconds. Like hitting the top of the water, he will begin to slow as he
27、 approaches the more dense air closer to Earth. But this will not be enough to stop him completely.If he goes too fast or spins out of control, he has a stabilization parachute that can be deployed to slow him down. His team hopes its not needed. Instead, he plans to deploy his 270-square-foot (25-s
28、quare-meter) main chute at an altitude of around 5,000 feet (1,524 meters).In order to deploy this chute successfully, he will have to slow to 172 mph (277 kph). He will have a reserve parachute that will open automatically if he loses consciousness at mach speeds.Even if everything goes as planned,
29、 it wont. Baumgartner still will free fall at a speed that would cause you and me to pass out, and no parachute is guaranteed to work higher than 25,000 feet (7,620 meters).It might not be the moon, but Kittinger free fell from 102,800 feet in 1960 - at the dawn of an infamous space race that captured the hearts of many. Baumgartner will attempt to break that record, a feat that boggles the mind. This is one of those monumental moments I will always remember, because there is no way Id miss this.