Trends in Space Navigation

The theme of this paper is based on the growing use of self-contained navigational systems in space navigation. A figure of merit, called the self-containment index (SCI), is defined in order to define quantitatively the degree of autonomy for which a system design is directed. The navigational problem of spacecraft is divided into problems of point-dynamics and rigid-body dynamics and the major factors are defined which deserve consideration in the understanding of the space navigational problem. Consistent with the requirements for low size, weight and power allocations and for very high accuracy and reliability tolerances, optical techniques are found ideally suited for space navigation. Open-loop and closed-loop methods of earth satellite navigation are presented and extended to the lunar navigation problem. Some advanced navigational concepts are given using nonrotating and track-while-scan instruments. The importance is emphasized of the increase in data-processing requirements and their part in accuracy enhancement through statistical techniques. A review of optical Doppler and lasers for measurement of distance and velocity is given. The concept of guidance management is proposed for consolidation of all the launch, orbital, midcourse, return and other guidance phases of a future multistage spacecraft into a single, integrated, selfcontained navigation system within the final upper stage.