载波相位平滑伪距在GPS/SINS紧组合导航系统中的应用

针对GPS/SINS紧组合导航系统中伪距噪声大从而引起组合导航系统精度低的问题,提出了将载波相位平滑伪距方法引入到组合导航系统中,利用具有较高精度的载波相位对低精度伪距进行平滑滤波,在建立观测方程的同时,为了减小Kalman滤波器计算量,选用最佳4颗卫星的伪距与伪距率作为观测值,并提出了一种四面体选星法,该方法不需要进行矩阵求逆运算,减小了运算量。利用光纤陀螺捷联惯导系统与GPS接收机搭建了实验验证系统,通过车载实验对所提出的方法进行了验证,实验结果表明,经过载波相位平滑后的伪距噪声得到了降低,从而能够进一步提高GPS/SINS组合导航系统的定位精度,其位置误差均方根值相比无载波相位平滑减小近40%。

Application of Carrier Phase Smoothing Pseudorange in GPS/SINS Tightly Integrated Navigation System

As the large pseudorange noise in the GPS/SINS tightly integrated navigation system leads to the low precision of the system, the method of carrier phase smoothing pseudorange is introduced into the integrated navigation system, and the low precision pseudorange is smoothed by the carrier phase with higher accuracy. At the same time, in order to reduce the computational complexity of the Kalman filtering, the pseudorange and pseudorange rate of the best four satellites are selected as the observation measurements, and a tetrahedral star selection algorithm is proposed here, which does not require matrix inversion. A verification experiment system is built by using fiber optic gyro SINS and GPS receiver. The proposed method is verified by on-board experiments and the results show that the pseudorange noise is reduced after the carrier phase smoothing with the positioning accuracy of the GPS/SINS integrated navigation system being further improved, and its root mean square(RMS) value of the position error is reduced by nearly 40% compared with that without carrier phase smoothing.