附有约束条件的GPS模糊度快速解算
LI Bofeng1 SHEN Yunzhong1,2(1 Dept.of Surveying and Geo-informatics Engineering,1239 Siping Road,Shanghai 200092,China)(2 Key Lab.of Modern Engineering Surveying of SBSM,1239 Siping Road,Shanghai 200092,China)
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摘要: 采用GPS相位观测值进行快速定位时,由于坐标与模糊度参数间的强共线性,造成浮点模糊度最小二乘解的精度很差,整周模糊度难以正确固定。在GPS的实际应用中,可以利用坐标参数与模糊度参数的约束条件,改善浮点模糊度的解算精度,减小整数模糊度的搜索空间。首先给出了这两类约束的通用模型,然后给出了不同情况下约束条件的具体形式,并导出了相应的GPS模糊度快速解算公式。用实例验证了算法的有效性。结果表明,采用约束条件,可排除大量错误的模糊度备选组合,从而提高模糊度的解算效率和成功率。因此,在GPS定位时,应尽可能利用各种约束条件。Abstract: In the rapid GPS positioning with carrier phase observations,the coordinate parameters and ambiguity parameters are highly correlated so that the float ambiguities resolved by least squares method are seriously biased.Therefore,it is difficult to correctly fix ambiguities.However,in the real applications,the various constraints exist in the coordinates or(and) ambiguities parameters.The constraints for coordinates can always be used to resolve float ambiguities with higher accuracy and the constraints for integer ambiguities can be employed to efficiently search ambiguities.Firstly,the general forms of constraint equations for coordinates and integer ambiguities are given;and the general solution is also derived.Each constraint equation for specialized situation is ulteriorly discussed in detail.At last,the numerical examples are implemented;and the results indicate that most of combinations of ambiguities can be rejected based on these constraints;and consequently success rate and efficiency of ambiguity resolution can be significantly improved.Therefore,the constraints should be fully used in GPS positioning.
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