零速修正在GNSS/INS紧组合导航中的应用研究

The Application of Zero Velocity Update in GNSS/INS Tightly Coupled Integration

为研究零速修正在GNSS/INS紧组合导航中的应用,提出综合利用GNSS/INS紧组合解算速度、IMU原始数据和多普勒观测数据的零速判断准则以及零速状态下的紧组合数学模型,并通过车载测试进行验证。结果表明,该零速判断准则对载体静止状态的判断与实际情况吻合良好,零速修正能够有效抑制载体静止状态下的IMU传感器误差积累,尤其是在卫星观测质量不好时。相对于不使用零速修正,在较短静止时间内,采用零速修正算法可以使卫星信号正常时的载体位置、速度精度分别改善27%、35%;卫星信号中断30-120s时,载体位置和速度精度分别改善16%-75%和87%-97%;但卫星信号正常与中断时,姿态改善效果都不明显。

In this paper, the performance of zero velocity update （ZUPT） in the GNSS/INS tightly coupled integration is researched. First, we propose a zero velocity judgment method by the utilization of GNSS/INS tightly coupled solver velocity solutions, IMU raw data and doppler data. Then, the mathematical model for the ZUPT added GNSS/INS tightly coupled integration is introduced in detail, and it is verified by vehicle testing. The statistics show that the new zero velocity judgment method is very effective in detecting the static state of the platform in comparison with real situations. By using this ZUPT mode, the IMU sensor error accumulation while stationary can be constrained visibly, especially in poor observation environmental conditions. Compared to the result without ZUPT, in a short time in the stationary state, the carrier position and velocity accuracy can be improved by 27% and 35% respectively in the quality of satellite observations, and 16%-75% and 87%-97% respectively in the case of 30-120 s satellite signal interruption. However, the improvements of altitude accuracy are not obvious whether the satellite signal is normal or interrupted when the stationary time is not so long.