GPS/INS超紧组合导航滤波器的优化设计

Optimized Design of the Navigation Filter in Ultra-Tight GPS/INS Integration

在极高动态条件下,GPS(global positioning system)接收机即使采用基带信号预处理技术,也无法精确地估计载波频率.而各通道的跟踪误差会通过传统导航滤波器相互耦合,并最终导致GPS/INS(inertial navigation system)超紧组合系统的崩溃.为解决这一问题,对伪距率跟踪误差建模,并将其扩充为导航滤波器状态量.但此时扩维导航滤波器维数过高,因此又通过星间单差和两阶段Kalman滤波对该滤波器进行了降维处理,从而在不损失导航精度的前提下,大幅降低了系统的计算复杂度.最后,以某次火箭弹试射时所遥测的惯性器件输出值为基础,通过半实物仿真验证了新型导航滤波器的有效性.

Under extremely high dynamic conditions,GPS receiver cannot exactly track carrier frequency,even if it is equipped with baseband signal pre-filter.Since the tracking errors of different channels are not independent any longer after passing through the traditional navigation filter,the ultra-tight GPS/INS integration may crash.To solve this problem,the pseudorange rate tracking errors were modeled and treated as the state variables of the navigation filter.However,the computational complexity of the filter with expanded dimension is too high.So on the premise of keeping navigation accuracy,dimension reduction was carried out through the use of inter-satellite single-difference and two-stage Kalman filtering algorithm.Finally,a semiphysical simulation,based on the gyro and accelerometer measurements telemetered in a rocket missile test,validates the effectiveness of the proposed methods.