| In order to ensure the flexibility, concealment and sudden attack of the nuclear submarine,it is demanded that the navigation should be passive and autonomous. The inertial navigation system does not get any information from the outside, also does not launch signals.The advantages of the inertial navigation system make sure that it is the best for the long endurance of underwater vehicle. However, the error of inertial navigation system is accumulated, so how to correct the error is the key of inertial navigation system. High autonomy, high positioning accuracy and strong anti-interference ability are the the advantages of Gravity aided navigation, so Gravity aided navigation has become a hot research topic in underwater passive navigation.The integrated navigation technology of marine gravity meter /inertial navigation system is based on the existing Chekan-AM marine gravity meter in our laboratory. The effective data of compensation is obtained by studying the error characteristics of marine gravity and compensating the error. Then, the simulation analysis of high precision inertial navigation is carried out, and the effect of gravity compensation is obtained. Major work:First,the basic equation and error equation of inertial navigation system is derived on the basis of the characteristics of space stable inertial navigation system. Basic equations and error equations relative to the earth's surface is obtained by the relation of conversion from inertial coordinate system to geographic coordinate system. Then the error characteristics of Chekan-AM marine gravity meter is analyzed, which includes zero drift, Eotvos effect,horizontal acceleration impact and damping delay. Then the program of amendments is proposed based on the different characteristics of error. Taking into account the gravity change anomaly is very weak, it is easy to be overwhelmed by high frequency noise in the vertical direction, and because of the gravity anomaly signal is non-stationary random signal,a priori information can not be obtained prior to measurement and other reasons, the traditional method of de-noising is not very effective,so wavelet analysis method which based on Mallat algorithm is proposed in this paper. The optimal wavelet decomposition level is determined by simulation tests and the conclusion is verified by the data of static test. The effect of wavelet filtering is come out by comparative analysis with Butterworth filter.The effective data is obtained by compensating the error of marine gravity meter. Before compensation, the impact of disturbing gravity on the space perturbations stable inertial navigation systems is analysed through simulation analysis and the effection on the acceleration, velocity, position, and orientation information is confirmed. Then the static and dynamic simulation test is carried out,and the effection of compensation is analysed. Gravity matching is also studied on the paper. Two categories of matching method in classical gravity is included, which is optimal estimation method for filtering and correlation values match,although there are more research in the relevant values match direction, the disadvantages of large amount of computation, the real poor, long time in matching make it hard to unfavorable combined with INS and the matching precision is not much improved. Because of no obvious relation in gravity anomaly and location information in latitude and longitude, so the effective equation is not established by using optimal estimation filter.Ant colony algorithm is a simulated evolutionary algorithm based on population and belong to stochastic search algorithm which is inspired by real ant colony collective behavior research in the nature the people for the collective behavior. A series of combinatorial optimization problems have been solved with this method. Efficient points are matched with this algorithm through effective external information as a constraint in this paper. The conclusion is drawn compared with MSD algorithm through simulation. |
PDF Full Text Request