Based on the facility the lab owned , we analyze single error and region error and compare different gps precision . the results showed that the precision of gps agl32 is the highest , than are gps25 oem plate and map330 , and maps 15 with the lowest precision 针对实验室现有的设备，分别对单点定位误差和区域定位误差进行试验、分析，对不同gps使用精度进行比较。得出如下结论：农用差分gpsag132定位精度最高，其次为gps25oem板和map330 ，而map315最差。
Taking the characteristics of road and bridge engineering into account , this paper makes systematic analysis and study on applications of static gps in data processing of surveying in road and bridge engineering : the feasibility of using single point positioning result as starting point is studied and the influence of it on baseline solution is discussed ; on account that the software provided along with instrument by vendors usually does not support coordinates in the independent engineering coordinates system from gps observations , a simple and effective method is represented for the gps data processing in the independent engineering coordinates system and is programmed . through real examples the method and programs are testified ; from gps surveying the wgs - 84 coordinates are acquired , while in reality coordinates in local coordinate system are needed , so conversion from wgs - 84 coordinates to local coordinates is necessary 结合路桥工程的特点，对静态gps在路桥工程控制测量中的数据处理作了系统的分析和研究： ?对单点定位结果作为起算点的可行性进行了研究，并探讨其对基线解算的影响； ?鉴于商家提供的随机软件往往不支持利用gps观测得到工程独立坐标系中坐标，为工程独立坐标系gps数据处理提供了一种简便有效的方法，并编制了相关的处理程序，通过实例验证，程序是正确的、方法是可行的； ? gps测量得到的是wgs - 84坐标，而实用上需要的是地方坐标系坐标，因而得把wgs - 84坐标转换地方坐标系坐标。
We write the program which used for fighting errors in absolute positioning . we also write the program which used for linear combinating in absolute positioning . from analyzing for the measurement of outer , we can conclude that we can use m estimation to estimate parameter in gps absolute positioning . lt has application value . using it , we can obstain the stable positioning result and remove the outer . in this paper , we calculate the data which from the baseline space of the gps calibration space . we also draw some conclusion using broadcast ephemeredes and smoothing pseudoranges . the positionging precision is in 1 - 2 meter 编制了gps绝对定位中抗差估计程序和应用线性组合进行单点定位的程序。通过对粗差量级的分析，得出在gps观测量存在粗差时， m估计是有其应用价值的，它使定位结果较为稳定，减弱和剔除了粗差的影响。应用线性组合程序对gps综合检定场数据基线网点进行计算，得出用广播星历和平滑后的伪距可以给出较好的结果，点位精度在1 ? 2米。
