Study Of Transfer Alignment Techniques In Strap-down Navigation System

Transfer alignment is a kind of initial alignment technique which uses the main INS with higher accuracy to calibrate the slave INS. It is a key technique for the new generation of rapid reaction and motor launch weapons.Regardless of the platform inertial navigation or the Strap-down inertial navigation system, the research on initial alignment all is take its system error equation as foundation, the error model establishment accurate or not direct influences the transfer alignment performance. The paper has analyzed the error source of inertial navigation, established the system error model, mainly has, velocity error model, position error model, attitude error model, accelerometer and gyro error model.The ship board deformation was brought by factors such as impact, perturbation of fitful wind, the noise of engine, change of temperature field of the wave and so on when ship's in water. So, it is necessary to consider the influence that ship board deformation brings for high accuracy weapon inertial navigation system. The paper analyzed the origin of ship's deformation, introduced the deformation sort, established the second-order Markov model of ship's deformation, and estimated the static misalignment angle and dynamic misalignment angle in transfer alignment of angle rate matching method.Different method of transfer alignment has its own characteristics, which can be applied in different areas. Calculating parameter matching methods have high accuracy but slow speed, while measuring parameter matching methods have high speed but low accuracy, and it is difficulty to make the both level misalignment angle and azimuth misalignment angle aligned to a higher precision at the same time. Combined parameter matching methods occurred for making up the disadvantages of the above methods. The paper finished the simulation and studies on the single parameters and combined parameters methods considering the ship board deformation, including velocity matching, attitude matching, angular rate matching, "velocity+ angular rate" and "velocity+ attitude" matching approaches. On the basis of above research and analysis, we can drawn the conclusion that "velocity+ attitude" matching method is more adapt to the modem war and high accuracy weapon inertial navigation system.