Design And Experimental Study On MIMU And Its Integrated System With GPS

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.