基于几何模型的惯性辅助PPP周跳修复与快速重新收敛

在复杂观测环境下,GNSS信号容易发生周跳和失锁现象,导致精密单点定位技术（PPP）模糊度重新初始化,影响定位精度及可靠性。本文基于PPP／SINS紧组合,提出了利用短时间内惯导递推的高精度位置信息辅助PPP周跳修复的几何模型。该模型采用原始观测值建立历元间差分方程,将周跳作为参数进行估计,而惯导提供的高精度位置作为带权的虚拟观测值参与平差解算,在固定周跳整数值后修复相位观测值,从而保持高精度的连续定位。以车载和机载两组数据分析了该方法的有效性,结果表明,引入惯性辅助能够显著加快PPP定位的重新收敛,实现周跳的准确修复。 

Cycle Slip Correction and Rapid Re-convergences with Inertial Aiding for Precise Point Positioning Based on Geometry-specified Model

The loss of lock and cycle slip on GNSS signals occurs frequently in the GPS denied environment where re-initialization forprecise point positioning (PPP)is usually required.It results in degrading theaccuracyand reliability of PPP. In this paper, an inertial aiding and geometry-specified cycle repair model is applied in PPP／SINS tightly coupled integration. The proposed model using uncombined observations builds the time-differenced carrier phase equations, which cycle slips are estimated and the displacement from inertial is treated as virtual observation for adjustment. When the cycle slips are fixed to correct integers, the original carrier phases are repaired accordingly to keep continues positioning with high precision. Two tests including vehicle and airborne data are analyzed to validate the proposed method. The results show that inertial aiding could accelerate PPP re-convergences significantly and success to repair cycle slips.