The Project Designing And Realizing Of The Combining Navigation Of FOG Strap Down Initial Navigation System And GPS

With the fleetly development of the national economic construction and national defense construction, military automation is an inevitable trend. In the complicated war environment, if we rely on too much external information, it will bring the deadly threat to the existence of the weapon platform certainly. So, the great improvement of the accurate guidance weapon is the independent guidance weapon. Facing the more and more tense international situation at present, a large number of stock aerial bomb should be reconstructed in our country , which is not only army's modernized need but also a need of the international politics and military affairs situation too. Because the navigation system of this text is established in reconstructing the existing ordinary cannonball, and there are less funds, we will try our's best to reach the best cost performance when selecting every part of corresponding products, such as the inertia components and GPS receiver, etc. And because the precision of the association navigation system is required slightly low, the main characteristic of the strapdown inertial navigation system (SINS)of this text is low cost, high cost performance and relatively high precision . but the technological degree of difficulty is not big.This text emphatically introduces several key technics in the design process or the system:1. Selecting coordinate of SINSStarting with the applying demand for the system, we has set up some kinds of suitable coordinate of this SINS : And utilizing the relation between every coordinate, we derives out the conversion square ; Having defined the posture angle range that the system outputs, and defined its truth of the posture angle aiming to the many values .2. Study on initial alignment of SINSConsidering that the precision of the system depends on the precision of initial alignment in a great extent, we introduce the ways and methods of initial alignment in detail, derive the linear error model of immobile base initial alignment, and analyse the error characteristic.3. Installing and CalibratingBecause having no entity platform, there is very high request in installing of SINS. But even adopting very good installing technique, it will still exist the installing drift angle, which could influent the precision of the SINS. So this text has put forward a very simple and practical calibrating method. This method not only can effectively separate all static drift parameters from the strap down inertial navigation system, but also can improve the compensation of installing drift angle greatly.4. Combination navigation systemThe systematic precision of navigation system disperses with time; better way tosolve this problem at present is to combinate with GPS. This text provides the systematic state equation and observing the equation and systematic state noise and observing noise data. Through the mode of combination of Kalman, we calculate the department equation per 100ms, and the observe equation per 5ms, and feedback each estimator to compensate the parameter with corresponding system. With this method we resolve the problem on the dispersing of the SINS precision.Finally, we provide the experimental data and the error curve after the system is finished, and compare the precision of SINS/GPS and SINS through these data.