Error Damping Technique Of Strapdown Inertial Navigation System

Strapdown Inertial Navigation System(SINS)is currently used in naval navigation field.It provides speed,position,attitude and other relevant information for ship navigation through system solution,because the carrier needs long time to navigate at sea.It is necessary to study SINS in-depth,to suppress its error,to meet the high-precision requirements of the system.In this paper,the damping technology of inertial navigation system is analyzed in detail,and the traditional damping technique is applied to the high channel of the inertial navigation system to restrain the divergence of the high-pass channel.Using the damping technology of modern control theory and is applied to the estimation of ocean currents.Usually in many ship navigation system is to ignore the day to the information,that is,the height and the sky to the speed of zero,but the carrier in the course of motion is also the existence of speed,which will affect the horizontal channel solution,For higher accuracy requirements of the system need to be considered.Because the pure inertial height channel is not stable,exponentially divergence,drift error drift solution,generally not as a result of the final solution to the system output,so we need to solve its divergence.To eliminate the three periodic oscillations in the horizontal channel of the inertial navigation system,a damping network is added to the loop.The divergence of the inertial navigation channel can also be solved by using classical control theory.In this paper,by adding the proportional and integral links in the height loop and using the auxiliary information of the external altimeter to design the second and third order high damping circuits,the damping parameters are selected by using the stability condition of the Rouse stability criterion and the dynamic requirements of the system itself.The simulation of the damping loop shows that the high channel third-order damping loop has better performance,the height channel can be stabilized quickly and is not affected by the zero offset of the accelerometer,and can compensate the hysteresis error of the altimeter.For an inertial navigation system with an electromagnetic telescope,or Doppler-based instrumentation with a depth less than the depth,the influence of the ocean current problem on high-precision navigation is not negligible due to the small velocity of motion.When the speed of the ocean current is constantly changing,the observation of the system will be inaccurate when the external speed equipment such as the electromagnetic speedometer and the inertial navigation system are combined.If the speed of the ocean current is added to the model of the system as the state quantity the key problem is to determine the ocean current model,because the different ocean currents model will be different,so the conventional Kalman filter will cause the model is not accurate,this paper aims at this problem,based on unknown parameters of the filtering method,the multi-model algorithm is applied to calculate the ocean current velocity as an unknown parameter,and the probability density estimation formula is constructed.The error of the inertial navigation system is estimated by the filter,and the velocity of the ocean current is estimated and compensated.The filtering damping method,which considers the external velocity error of the ocean current,can avoid the influence of the ocean current on the performance of the integrated navigation system.