Research On MEMS-MINS/GPS Intergrated System

With the development of science and technology,satellite navigation has been gradually popularized from the original military field to people's real life and work.As the most classical autonomous navigation,inertial navigation has the characteristics of high concealment,autonomy and strong anti-interference,but in view of the fact that its error accuracy diverges with time,the integrated navi gation system of inertial navigation and global positioning system is more widely used in practical engineering.At present,the most classical combination of integrated navigation products in China is loosely coupled and tightly coupled.With the development of inertial devices,micro inertial devices are small in size,light in weight and carrying in engineering.With the characteristics of convenience,the traditional optical inertial devices have been gradually replaced in some fields.In this paper,several integrated methods of micro-inertial navigation system and global positioning system in engineering are studied.This paper mainly analyzes and compares the principle,performance and observability of the two combination modes of loosely coupled and tightly coupled navigation,and obtains the characteristics,advantages and disadvantages of the two combination methods.Firstly,some basic theories and formulas of inertial navigation and GPS satellite navigation are briefly summarized.There are mainly the concepts of coordinate system in micro inertial navigation,the transformation between coordinate systems,the specific force equation and the solution equation of velocity position attitude angle.Secondly,the components of GPS and the contents of e ach part are briefly summarized,and the absolute positioning principle and differential positioning principle of GPS are briefly introduced.Then it briefly summarizes the related knowledge,basic principle and concept of Kalman filter,as well as several filtering methods of Kalman filter in engineering,and finds one of the most suitable filtering methods for this lesson.The filtering method of the problem is proposed,and then two combination methods are proposed,namely,loosely coupled and tightly coupled.Then the modeling of loosely coupled and tightly coupled filter is carried out by using the previous basic principle.Secondly,the performance and characteristics of the modeled integrated navigation are studied.Firstly,the concept of PWCS is proposed,and a method which can analyze the observability of this kind of system is found.The SOM instead of the TOM,and the rank of the SOM is obtained to reflect the TOM.Secondly,the observability of the two kinds of combined navigation systems is analyzed by using the above methods,and the observability characteristics of the two kinds of systems are obtained,and the corresponding comparison is made to draw the conclusion.In addition,the observability analysis of the compact integrated navigation system in the absence of stars is added,and the observability of the tightly coupled navigation system in the absence of stars is also added.Comparing two conclusions,the corresponding conclusions are drawn.Finally,the simulation analysis of the two combination methods is carried out.Firstly,the curves of velocity,position and attitude angle error with time are obtained under the condition of only micro-inertial navigation system.Secondly,under the condition of global positioning system(GPS),the loosely coupled mode is simulated and analyzed,and the corresponding errors of the corresponding three curves in the axis of three coordinates are obtained and compared with the curves of single inertial navigation.Then the navigation system with the condition of tightly coupled is simulated,and the simulation results are compared with the simulation results of the previous loosely coupled,and the conclusion is drawn.Finally,the case when the number of tightly combined observation satellites is less t han 4 is simulated and compared with before.Draw the conclusions.