1、手持 GPS 在膜下滴灌工程测量中的应用Application of portable GPS in drip irrigation under film in engineering measurement膜下滴灌受形地貌要素影响，在施行时有必要做好地块鸿沟测绘和施工放样作业。如地块规模丈量、土地平整度丈量、提水井方位丈量、干支管布设等。为满意丈量精度需求需选用手持 GPS 技能进行丈量。使用膜下滴灌技能的开端作业就是对地块进行有用的丈量。既要进步作业效率又要确保丈量精度，因而选用手持 GPS 进行测绘是最佳挑选。Drip irrigation under film affected by
2、topography factors, in the implementation of necessary to block gap surveying and construction lofting operation. As the scale of the land survey, land flatness measurement, lift wells range measurement, pipe laying. Satisfactory measurement accuracy requirements needed to use handheld GPS skills fo
3、r measurement. Beginning of drip irrigation under film operation skill use is useful measure to block. Not only to improve work efficiency and ensure the measurement precision, so the selection of handheld GPS mapping is the best choice.手持 GPS 定位办法为单点定位，选用的是 WGS84 坐标体系。在http:/ http:/ http:/ http:/ h
4、ttp:/ 1980 西安坐标系，因而需要在不一样坐标系之间进行变换，使手持 GPS 丈量的当地数据变换为1980 西安坐标系的效果。当前，2 坐标体系之间的变换办法有 3 参数法、5 参数法和 7 参数法。在进行膜下滴灌丈量中，咱们选用的是 5 参数法。先用 WGS84 坐标系下的长半轴和扁率减去 1980 西安坐标系下的长半轴和扁率得出 DA，DF；然后使用 GPS 点的 84 空间直角坐标系下的坐标减去 1980 西安空间直角坐标，这样就得出相应的DX，DY，DZ 这 3 个参数。首要收集 3 个已知点的 1980 年西安坐标系的坐标和 1985 国家高程基准下的正常高。 GPS pos
5、itioning method for single point positioning hand-held, uses the WGS84 coordinate system. Drip irrigation under film in surveying and mapping, because the 1980 Xian coordinates, thus the need for transformation between different coordinate system, the transformation of handheld GPS measurement of lo
6、cal data for 1980 Xian coordinate effect. At present, the transform method between 2 coordinate system with 3 parameters, 5 parameters method and the 7 parameter method. In drip irrigation under plastic film in the measurement, we used is the 5 parameter method. 1.1 detailed transform calculation me
7、thod using WGS84 coordinates of the semi-major axis and ellipticity of minus 1980 Xian coordinates of the semi-major axis and http:/ http:/ http:/ http:/ http:/ of the obtained DA, DF; and then use the GPS point of the 84 rectangular space coordinates of minus 1980 Xian rectangular space coordinates
8、, so that the corresponding DX, DY, DZ these 3 parameters. Coordinate the first collection of 3 known points 1980 Xian coordinates and 1985 National Height Datum of normal high. 依据以上各项数据，核算出五个变换参数为：然后把这 5 个参数输入手持 GPS 中，在已知控制点上进行丈量，与已知坐标相比拟。若精度到达丈量的需求，则开端进行丈量；若精度达不到丈量的需求，则大概从头核算变换参数。 On the basis of
9、the above data, accounting for five of transform parameters : then put these 5 parameters input handheld GPS, measured in known control points, compared with the known coordinate fitting. If the precision reaches the measurement requirements, start measuring accuracy; if not up to the measurement re
10、quirements, probably from the accounting transformation parameters.为了验证所求变换参数的准确性，又在其他几个已知点上施测了新的坐标，实测坐标与已知点坐标进行了比拟，由此咱们能够断定在地势条件和卫星条件杰出的情况下，观测必定的时刻，点位的中差错可到达 3 m 以内。 In order to verify the accuracy of the transform http:/ http:/ http:/ http:/ http:/ and measured the new coordinate applied in severa
11、l other known point, coordinates and the known coordinates measured were compared, thus we can conclude that on the conditions and satellite condition outstanding cases, observation must be time, point position error can reach 3 m.手持 GPS 的精度能满意膜下滴灌工程的精度需求，所以在进行膜下滴灌工程丈量时，用手持 GPS 施测土地的鸿沟和机井的方位，然后依据所测的
12、面积和方位，对输水干管-支管-毛管进行布设。在实践丈量中，如果有少数的林地，则在丈量林地周围时，观测时刻要恰当的延伸，才干到达很好的精度。手持 GPS 定位快，精度较高，约束条件少，作业效率大大进步。Handheld GPS precision accuracy requirements engineering under drip irrigation with film, so the drip irrigation engineering measure, with a handheld GPS surveying land gap and well location, and then
13、 based on the area and range measurements, to layout on water trunk - Branch - capillary. In practical measurement, if a handful of woodland, in the measurement of woodland around, observing time to the appropriate extension, can achieve good accuracy. Handheld GPS positioning fast, high precision, less restrictive conditions, work efficiency is http:/ http:/ http:/ http:/ http:/ improved.
