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MIMU及其与GPS组合系统设计与实验研究
Design and Experimental Study on MIMU and Its Integrated System with GPS
【作者】 尚捷;
【导师】 顾启泰;
【作者基本信息】 清华大学 , 仪器科学与技术, 2005, 博士
【摘要】 随着 MEMS 技术和微光电技术的迅速发展,出现了微型惯性测量组合(MIMU),由于它们在体积重量、成本、可靠性等方面的优势,给惯性测量技术带来一次全新的变革和发展机遇。其不足之处是目前 MIMU 的测量精度还比较低,使其应用受到一定限制。因此,如何利用 MIMU 的优势来扩展其应用领域;克服不足之处来探索其应用的方式,成为该技术领域的研究重点。本文正是围绕这两个问题开展研究工作。首先,从典型 MIMU 器件入手,进行了实验研究。对其中主要器件VG941-3AM 微型光纤陀螺作了 ARMA 模型辨识,并设计了卡尔曼滤波器,减小其输出噪声,为提高系统精度提供了有效手段。MIMU 的设计采用内装式结构,外部具有六个正交基面;并建立了数学模型,采用正交最小二乘法处理实现在一个水平基准平面上翻滚进行快速标定。同时提出一种基于虚拟噪声的静基座捷联系统现场最优标定方法,同两位置或多位置方法相比,其结构简单、省时、易于实现,既能保持一定的姿态精度,又能大大降低导航和定位误差。然后,在上述研究工作基础上,完成了国内首枚弹射实验用模拟弹。采用参数化三维实体设计,精确模拟实际产品导弹的机械特性;模拟弹内部的微型惯性运动参数测量系统(MIMS)可自主的测量导弹弹射时的三维运动参数。经多次实验证明其工作可靠,测量精度高,动态性能好。最后,完成 MINS/GPS 组合系统实验样机。针对其组合方式的特点,分别采用状态与偏差去耦估计算法和 U-D 协方差分解与序贯处理算法,前者计算量小,后者不受可见星数目的限制。提出了一种姿态修正的方法,推导了利用姿态误差角估计修正姿态阵的公式,仿真和实验数据验证了该方法的有效性和可行性,特别适用于陀螺零偏较大和稳定性较差的场合。此外,对组合系统进行了多次车载实验。实验结果表明,系统工作正常,定位精度同 GPS 相当。通过实验,还仔细研究了两种组合方式以及修正间隔时间、GPS 失锁等对定位精度的影响。对于廉价性的 MINS/GPS 组合系统更适于采用位置、速度组合方式和状态偏差去耦估计算法,不仅具有较高的精度而且计算量小,易于工程实现。
【Abstract】 With the rapid development of MEMS and micro optics and electronicstechnology, the Micro Inertial Measurement Unit (MIMU) came into being.Due to the advantages in size, weight, cost and reliability, they bringinnovation and opportunity in the field of inertial measurement. But the lowmeasurement precision is their major shortcoming and also is an obstacle toapplications. Therefore, how to expand their application field with theiradvantages and how to improve their work by overcoming disadvantages havebecome a research hotspot of this technical field. They are also the focuses ofthis dissertation. First, the experimental research on typical MIMU sensors was made.The ARMA model identification and Kalman filter design of VG941-3AM, aminiature fiber optic gyroscope, are presented to reduce the FOG’s outputnoise and provide an effective way for improving system accuracy. A specialinside-placed structure is adopted in MIMU design to obtain six orthogonalstandard planes outside. After modeling the calibration procedure, theorthogonal least square algorithm is introduced to achieve a quick calibrationmethod which needs only a horizontal standard plane to roll on. An on-fieldstationary SINS optimal calibration method is also presented, which is basedon fictitious noise. Compared with two-position and multi-position calibrationmethod, this simple, fast and convenient method can not only maintain theattitude accuracy but also reduce the navigation and positioning errordramatically.Secondly, relying on the above fundamental research work, a simulatedmissile for ejection experiment was implemented firstly in China. Toprecisely simulate the actual missile’s mechanical property, the parameterized3-D solid engineering method is used. The Micro-miniature InertialMeasurement System (MIMS) inside simulation missile can independentlymeasure the 3-D ejection movement parameters, and the reliability, accuracyand high dynamic measurement of the simulation missile has been proved byseveral ejection experiments.Finally, an experimental prototype of the MINS/GPS integratednavigation system was implemented. Aimed at different integration modes,the state bias decoupled estimation and U-D covariance factorization withsequence processing algorithm are designed respectively, the first one ischaracterized by less computations and the second one is not influenced by thequantity of available satellites. An attitude updating method is also presented,and the equation to update attitude matrix with the attitude error anglesestimation is deduced. The computer simulation and experimental data testinghave proved the effectiveness and feasibility of this updating method. Theattitude updating method is especially suitable for integrated systems whichare composed by the gyroscopes with greater zero drift and worse stability.Furthermore, several on-vehicle experiments were made. The resultsshow that the integrated system works properly and the positioning accuracyis equivalent with GPS. By analyzing these experiments, the influences to thepositioning accuracy caused by the two different integrated modes, updatinginterval time and GPS unlock situation are also studied in details. The systemapplied with position/velocity integrated mode and state bias decoupledestimation algorithm is more becoming to low cost MINS/GPS integratedsystem, for its advantages in relatively high accuracy, less calculations andsimple structure.
【Key words】 MIMS; Movement Parameter Measurement; GPS; Integrated Navigation;