外杆臂效应对于船用捷联惯导罗经对准影响分析

摘要

捷联惯导系统在动基座罗经对准中需要计程仪提供速度,然而计程仪(位于船底部)和捷联惯导系统(位于罗经室)之间存在的外杆臂效应使得计程仪提供的速度存在误差.为分析外杆臂效应对动基座罗经对准性能的影响,推导了船舶纵摇、横摇、转弯情况下,外杆臂效应导致的速度误差表达式,同时,建立了速度误差与罗经对准误差角之间的关系,进一步推得外杆臂效应速度误差对于罗经对准的影响.理论分析与仿真表明:外杆臂效应会引起罗经对准水平和方位对准误差,该误差与摇摆和转弯的幅度,外杆臂的长度构成递增关系.%A strapdown inertial navigation system ( INS) requires the reference velocity form a log during in-motion gyrocompass alignment. However, the outside lever arm exists since locations of the log ( located on the bottom of a ship) and the strapdown INS ( located in the compass cabin) are different from each other, which would lead to errors of reference velocities that are brought into gyrocompass alignment. In order to study the effect of outer lever-arm on gyrocompass performances, we deduced the expressions of velocity errors aroused by the outside lever arm in the cases of pitch, roll and heading changes. Meanwhile, we constructed the relationship between velocity errors and gyrocompass alignment errors. Furthermore, we obtained effects of the outside lever-arm on gyrocompass alignment. Theoretical analysis and simulation showed that the outside lever arm could lead to level and heading misalignment errors for gyrocompass alignment which increase with amplitudes of sway and turn as well as length of the outside lever arm.