惯性辅助的单频GPS整周模糊度快速求解*

利用单频GPS载波相位差分技术进行快速精密相对定位时,由于观测历元少,卫星空间分布变化缓慢,双差观测方程设计矩阵呈复共线性而导致法矩阵病态,使得整周模糊度无法固定。针对这一问题提出了惯性导航系统(INS)辅助GPS整周模糊度求解算法,将惯性伪距单差、GPS伪距双差、载波相位双差联立得到模糊度浮点解及其协方差阵,并用LAMBDA算法求解出整周模糊度固定解。分析了引入惯性信息改善复共线性和病态性的原因。最后利用GPS实测数据与仿真INS数据进行实验验证,结果表明INS辅助信息使得法矩阵条件数减小两个数量级,模糊度衰减因子(ADOP)下降55.81%,整周模糊度固定解求解的时间缩短75.44%,方法可行。

Fast Resolution of Single Frequency GPS Integer Ambiguity with INS Aiding

When single-frequency GPS carrier phase differential technology is used in rapid precision relative positioning,due to less observable epochs and slow change of satellite geometric distribution, the design matrix of double-difference observation equation is collinear, which lead to the normal matrix becomes ill-condition, furthermore, ambiguity is hard to resolved. In view the problem, an INS aided GPS integer ambiguity algorithm is proposed. INS single-difference pseudo range, GPS double-difference pseudo range and GPS double-difference carrier phase is used to get the float ambiguities and their variance-covariance matrix. Then LAMBDA algorithm is used to get the integer ambiguity. The reason why INS aided information can improve collinear and ill-condition is analyzed. Finally, an experiment is conducted with the GPS test data and the inertial navigation data from simulation. The results show that, with INS aided information, the condition number of normal matrix is dropping two orders of magnitude, 55.81% reduction of ADOP and 75.44% less time to resolve integer ambiguity. The method is feasible.