精密单点定位（PPP）技术可利用单台接收机在全球范围内直接得到高精度的坐标信息。目前，北斗卫星导航系统（BDS）已经具备了亚太大部分地区的区域服务能力，其精密定位技术已成为国内外GNSS领域的研究热点。将北斗应用于CORS系统，可解决现有区域基准单一GPSCORS模式带来的安全问题。以甘肃省CORS站为例，利用PPP技术对北斗CORS定位精度进行了测试，与GPS相比，其差值在0.07 m以内。

In order to study on the positioning accuracy of BDS when used in CORS positioning service and on the security issues caused by GPS,the paper tested the positioning accuracy of BDS PPP,calculated the observed data in Gansu province CORS with Ambizap algorithm, and comparatively analyzed the precise point positioning results of GPS CORS and BDS CORS. Result showed that the deviation of coordinate components would be between mm~cm level.

由于GPS卫星采用高精度的星载原子钟，使得利用GPS接收机城肘可以达到比较理想的精度。利用AR模型对6PS接收机的钟差数据进行建模分析，通过拟合比对，建立合适的预报模型，预报的精度达到了较好的效果。

针对青海地区地理环境的特点和大地控制网的现状,从GPS控制网设计与布测、数据处理、控制网质量检测和成果管理等方面对青海地区三级GPS大地控制网的建立进行了分析研究。在此基础上,总结了在高原困难地区建立GPS网的一些经验。

For solving the information shortage of single remote sensing image and the synthetic application of multi-sources RS images to improve space resolution and spectral resolution effectively to apply for yielding army topographic maps in cisborder of difficulty area and oversea target,this paper discusses the idea to design of Photorgrmatry Image Fusion System and introduces the application of fused RS image produced by this system in photogrammetry.

The role of data quality assessment on the third order GPS geodetic network is introduced at first.The methods and index of data quality assessment are present then.Using TEQC,48 stations GPS observation data in qinghai area of the third order GPS geodetic network are assessed,and the index are analyzed statistically combined with baseline resolution.

With the angle and distance measurement's precision improvement of total station instrument,EDM trigonometric leveling has become major method in leveling.At first,error effects are analyzed in the paper.Then the methods of precision improvement of EDM trigonometric leveling are discussed.In order to assess the efficiency of different methods,a concept of efficiency equation is presented.At last,an example is given to compare the precision and efficiency in different methods.