一种改进的模糊度子集选取方法及其性能评估

模糊度固定(ambiguity resolution, AR)能在一定程度上加快精密单点定位收敛并提高定位精度。但是模糊度固定率和计算效率会随模糊度数量的增加而降低，因此部分模糊度固定(partial ambiguity resolution, PAR)备受关注。PAR技术的关键在于模糊度子集选取，提出了一种改进的模糊度子集选取法，将高度角、信噪比以及模糊度方差联合作为模糊度子集选取的指标。实验结果表明：静态模式下，相比于全模糊度固定(full ambiguity resolution, FAR)和基于高度角的PAR方法，该方法的固定率分别提升9.65%和2.56%,首次固定时间分别缩短6.86%和3.43%,收敛时间分别缩短15.57%和5.13%,当三种方法固定率大致相同时，定位精度分别提升4.74%和5.39%;动态模式下，该方法的固定率分别提升22.75%和0.92%,首次固定时间分别缩短12.44%和0.44%,当三种方法固定率大致相同时，定位精度分别提升3.50%和4.89%。总体而言，无论是在静态还是动态模式下，该方法相比于FAR和基于高度角的PAR方法，性能均有所提升。

An improved ambiguity subset selection method and its performance evaluation

The convergence of precise point positioning (PPP) can be sped up and the positioning accuracy can be improved by using ambiguity resolution (AR) to a certain extent. However, the fixed rate of AR and computational efficiency will decrease with the increase in the number of ambiguities. Therefore, partial ambiguity resolution (PAR) has attracted much attention. The key of the PAR is the selection of ambiguity subsets, an improved ambiguity subset selection method is proposed, in which the elevation, signal-to-noise ratio (SNR) and ambiguity variance are combined as the indicator for ambiguity subset selection. The experimental results show that compared to the FAR and the PAR based on the elevation, the improvement of fixed rate, time to first fix and convergence time of the proposed method are 9.65% and 2.56%, 6.86% and 3.43%, 15.57% and 5.13% respectively in the static mode. When the fixed rate of the three methods is almost the same, the improvement of positioning accuracy is 4.74% and 5.39% respectively. For the kinematic mode, compared to the FAR and the PAR based on the elevation, the improvement of fixed rate, time to first fix of the proposed are 22.75% and 0.92%, 12.44% and 0.44%, respectively. When the fixed rate of the three methods is similar, the positioning accuracy is improved by 3.50% and 4.89%, respectively. Overall, this method can improve the performance compared to FAR and PAR based on the elevation for both static and simulated kinematic mode.