当观测信息冗余度小或出现异常时,仅依靠GPS单历元数据难以获得可靠的定位结果,需借助历史信息改善定位精度和可靠性。导出了Bayesian递推算法的一般形式,建立了基于移动窗口的牛顿向前插值模型与常速度、二次曲线最小二乘拟合模型的先验信息获取方式,引入了当前历元相关观测方程的抗差估计,并采用实测GPS动态数据计算分析,结果表明:抗差估计能有效抑制粗差对GPS定位结果的影响;拟合模型对误差具有平滑作用,其中二次曲线模型明显优于常速度模型,但两者均需实时计算拟合系数;而牛顿向前插值模型系数恒定,计算简单,显著提高了定位精度及可靠性。
It is difficult to obtain the reliable positioning restflts when observations are influenced by abnormity or low redun- dancy. Historical information should be applied to improve the positioning precision and reliability. Basing on Bayesian theorem, a general recursive algorithm was developed. According to various prior information accessing, the Newton forward interpolation model, the constant velocity and quadratic curve fitting model were constructed in a chosen time window. Robust estimation for correlated observations was also introduced in the present epoch. In the end, a real-life example is tested, and the results show that robust estimation is effective to reduce the influence of outliers ; Fitting model can smooth errors, and quadratic curve is superior to constant velocity ; Nevertheless both of them need to compute the fitting coefficients ; however, the Newton forward interpolation model holds a constant coefficient and significantly enhances the precision and reliability.