一般的GPS数据处理软件都是采用上述步骤进行计算的，其中只有第2步涉及转换参数。鉴于我国曾使用不同的坐标基准（BJ54、State80、 Correct54），各地的重力值又有很大差异，所以很难确定一套适合全国且精度较好的转换参数。通行的做法是：在工作区内找三个以上的已知点，利用已 知坐标和所测Wgs84坐标，求解七参数。若多选几个已知点，通过平差的方法可以获得较好的精度。

-General GPS data processing software are used in calculating the above steps, only Step 2 involves the conversion parameters. In view of our country have been benchmarks for the use of different coordinates (BJ54, State80, Correct54), around the gravity value, and very different, so it is difficult to determine the accuracy of a better suited to the country and the conversion parameters. Practice is: to find in the work area more than three known points, using the known coordinates and measured coordinates Wgs84, solving seven parameters. If more than a few known points selected by the method of adjustment can be a better accuracy.