The invention provided an inter-
satellite measurement and gyro attitude 
orbit integrated 
smoothing estimation method. According to the inter-
satellite measurement and gyro attitude 
orbit integrated 
smoothing estimation method, relative navigation and 
attitude determination of non-cooperative targets are realized via following steps: formation 
satellite attitude integration dynamical equation is used, and 
observability problems of the 
system are solved via using a large amount of inter-satellite measurement and gyro measurement data combined with Kalman 
smoothing algorithm, wherein the formation satellite attitude integration dynamical equation is composed of attitude dynamics constructed from 
quaternion error under inertial frame, and 
relative motion dynamics constructed under track 
satellite orbit frame, only based on gyro and inter-satellite measurement information. Compared with existing technology, advantages of the inter-satellite measurement and gyro attitude 
orbit integrated smoothing 
estimation method are that: 
system configuration requirements are simple, only inter-satellite measurement and gyro information is needed, dependence of the 
system on orientation systems such as 
star sensor is reduced, and system reliability is increased; the inter-satellite measurement and gyro attitude orbit integrated smoothing estimation method can be used for satellites of non-cooperated formation; an indirect measurement equation is adopted, 
coupling properties of an 
observation matrix are poor, 
algorithm calculation is simple, and 
engineering application is convenient.