This paper discusses the need,the significance and the feasibility of information reorganization,and the application of such reorganization to the development of subjectbased information navigation tools.

The paper expatiates the concepts and characteristics of invisible web,expatiates the reason of its forming in the information navigation system.

The content analysis based on information resources appentds knowledge to information navigation,and makes information navigation intelligent.

The category of the construction of literature resources of information navigation database for key disciplines in colleges and universities mainly includes information service in the worldwide web and the digitalization & virtualization of the number of books collected in the library.

This paper proposes an accurate orbit determination technique to accurately determine orbit elements of a spacecraft equipped with a GPS receiver according to navigation messages from the receiver.