三频差分GNSS/INS紧组合模型

Triple-frequency differential GNSS/INS tightly coupled integration model

北斗卫星导航系统已经提供三频信号的位置服务。针对目前尚无关于北斗三频信号的GNSS/INS紧组合研究的现状,将三频模糊度解算算法与紧组合结合,构建了三频差分GNSS/INS紧组合模型。给出了新模型的观测方程和模糊度解算方法,分析了新模型的优点。进行了车载组合导航实验对比新模型与经典模型,结果表明:新模型的解算时间消耗远少于经典模型,在9颗可视卫星时,新模型的总解算时间仅为经典模型的55.53%;卫星数的增加对新模型解算时间的影响不显著;新模型能够获得和经典模型相当的精度,位置差别均方根在毫米级,速度差别均方根在厘米级,姿态差别均方根在0.01°级别。新模型利用了三频模糊度解算速度快的优点,又有效地削弱了其不稳定性对定位结果的影响,为基于三频信号的GNSS/INS紧组合做了前沿性研究。

While Beidou navigation system has already provided the location service with triple-frequency signals, the research on GNSS/INS tightly coupled integrated system with triple-frequency signals has not yet started. Thus, a triple-frequency differential GNSS/INS tightly coupled integration model is presented by combining the three-carrier ambiguity resolution（TCAR） with tightly coupled integration. The benefit of the new model is analyzed based on the given observation equation and ambiguity resolution algorithm. A land vehicle test is performed to validate the new model by comparing it with the traditional model. Experiment results show that the time consumption of the new model decreases significantly compared to traditional model. The time consumption of the new model is only 55.53% of the traditional model when 9 satellites are visible. Meanwhile, increasing the number of satellites only has a slight effect on the time consumption of the new model. The root mean square errors of position, velocity and attitude are millimeter level, centimeter level and 0.01° level, respectively, indicating that the new model can achieve the same accuracy level as the traditional model. In general, the triple-frequency differential GNSS/INS tightly coupled integration model utilizes the fast speed of TCAR while alleviates the drawback of its instability. This study lays a foundation for the further research of triple-frequency differential GNSS/INS tightly coupled integrated system.