GPS速度测量在航空重力测量中具有重要的作用。根据飞机平稳飞行的状态,建立了严密的状态方程,利用常加速度模型的速度预测值,构建了观测值验前残差检验量Q,并给出其误差源:观测误差与速度预测误差,根据检验量Q的统计特性结合IGG Ⅲ抗差方案,对含粗差的观测值作降权处理。采用静态数据分析观测误差的统计特性,并给出其模型参数,同时分析了理想运动状态下的速度预测精度以及数据采样率与新方法粗差探测能力之间的关系。通过静态和动态算例表明,新方法能有效探测出小于1周的粗差。
Precision velocity plays an important role in airborne gravimetry. Since the aircraft in a state of stable flight, we could establish a strict state equation with constant acceleration model for it, then obtained predicted velocity which was used for constructing a priori residual Q to detect the gross errors. Theoretical research showed that Q was influenced by the accuracy of predicted velocity and the measurement errors. According to the statistical features of Q combined with IGG Ⅲ principle, we could lower the contribution of the observation that contained the gross errors. Static testing was used for analyzing the characteristic of measurement errors as well as the accuracy of predicted velocity under the simulated ideal flight environment where the acceleration was approximate to a constant, the results also showed the relationship between the sampling rate and the ability of detecting gross errors. Both the static and kinematic tests demonstrate that new method can well detect the gross error smaller than 1 cycle.
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