GNSS最优载波相位平滑伪距研究

平滑常数是影响载波相位平滑伪距精度的关键参数,实际数据处理时主要依据经验设定平滑常数。这种主观设定过程缺乏理论依据,无法达到最优平滑效果。针对此问题,以适用于实时GNSS载波相位平滑伪距的经典Hatch递推滤波算法为基础,在连续时间域上分析了载波相位平滑伪距误差的主要构成,给出了总误差估算公式,分析了平滑常数对平滑精度的影响传导机制。进一步,采用令平滑总误差最小为目标的极值法推导给出了最优载波相位平滑常数的计算公式,给出了最优载波相位平滑伪距的完整处理步骤。最优平滑常数算法在数学意义上最优,大幅压缩了伪距测量误差,又不会引入过大的电离层发散误差。通过两个实际算例,证明了算法有效性。

Optimal Smoothing of GNSS Pseudo-Range by Carrier Phase

The accuracy of carrier phase smoothed pseudo-range is seriously affected by the smoothing constant,which is an important parameter usually set by experience in practices of data processing.This arbitrary way has no theoretical basis,and the smoothing results are not optimal.To find a solution to this problem and starting from the classical Hatch recursive filtering algorithm,the main error components of the smoothed pseudo-range are analyzed in the continuous time domain.The total error estimate formula is given and the influence transmission mechanism of the smoothing constant on the smoothing accuracy is analyzed.Furthermore,the extreme value method aiming at minimizing the total error is adopted so that the formula for computing the optimal smoothing constant is derived,and the complete processing steps of the optimal smoothing are availed.The algorithm is mathematically optimal,and the use of the smoothing way significantly reduces pseudo-range errors while avoiding introduction of too much ionosphere divergence errors.The effectiveness of the algorithm is validated by two examples.