区域GPS空间基准网的建立

随着GPS的广泛应用，如何提高GPS的定位效率，实现实时定位，已经成为有待解决迫切的问题，目前RTK技术(实时动态全球定位系统)不需要数据的后处理即可快速定位，但在定位之前，需要在足够的已知点上进行观测，计算获得所需区域的坐标系统的转换参数，这在很大程度上影响了RTK的定位效率和点位的相关与一致性，此外，目前许多城市的地方坐标系统与国家坐标系统之间缺乏精确严格的换算关系，结合区域GPS空间基准网的建立项目，阐述了GPS空间基准网的布设与施测、投影与坐标系统转换等相关的数学模型和解算方法，探讨了多套参数的差异与应用，观测分量的误差对于拟合参数精度的影响等问题，并给出了相应的分析数据．基于上述方法可以获得区域统一的、精确的多套坐标系统之间的转换参数，将WGS84的大地坐标与现行实用的坐标系统如1954年北京坐标系统、80西安坐标系统以及地方坐标系统紧密联系起来，从而实现坐标系统之间实时精确的转换，为RTK实时定位奠定基础。

Establishment of Regional GPS Space Datum Network

With the wide application of GPS technology, how to improve GPS productivity related to real_time location has become the urgent affair. At present RTK GPS (Real Time Kinetic Global Positioning System) can finish surveying projects quickly without post processing. However, it is needed to observe at the known control points to calculate the regional conversion coefficients of the coordinate system before surveying, which tends to affect RTK's productivity and data's coherence to a great extent. Moreover, the local coordinate systems in the cities of our country lack in direct and precise connection to the geocentric coordinate system and the national coordinate system. We can get several sets of uniform, reliable and precise conversion coefficients and ascertain the close relations among different coordinate systems, such as Beijing geodetic coordinate system 1954, Xi'an geodetic coordinate system 1980, World Geodetic system 84 and local coordinate system, etc. by establishing the regional GPS space datum network, from which we can get different system coordinates. In this paper, related technologies such as designing and surveying GPS space datum network, involving mathematical model flow and arithmetic are presented with examples. The comparision of the coefficients between two-dimension and three-dimension as well as the effects of geodetic height on fit coefficients and attitude are also presented.