In marine navigation and positioning applications, the Navy Navigation Satellite System (NNSS) has been in use for almost ten years. In all of the commercial navigation system applications, the NNSS has been used as a position fixing adjunct to other continuous-tracking systems such as a doppler sonar navigator. Thus, the periodic NNSS position fixes have been used to update (correct) positions determined by the other systems which actually provide the continuous tracking information for navigation purposes. One serious restriction to this technique is the requirement that an accurate external measurement of user velocity during each satellite pass be available in order to maintain high fix accuracy. In many critical offshore applications this requirement has been contradictive, leading to the necessity for using an extremely accurate continuous tracking system such that the value of the NNSS itself has become questionable. The author describes methods which have been developed for removing this restriction and thereby allowing the accuracy of external systems to be considerably relaxed without compromising NNSS positioning accuracy. These techniques have been used with high success in some specific post-project mapping applications as reported previously. Recently,these techniques have been improved upon for use with a minicomputer for at-sea applications. In order to gain insight into the expected performance of the system in various applications, a simulator was developed which provides estimates of per-pass calibration accuracies using different types of navigation system measurements. This simulator is described in more detail in the Appendix while typical examples of calibration accuracies for some standard configurations are described.

Media Info

  • Features: References;
  • Pagination: p. 421-430

Subject/Index Terms

Filing Info

  • Accession Number: 00138182
  • Record Type: Publication
  • Source Agency: Offshore Technology Conference
  • Report/Paper Numbers: V1, OTC 2463 Proceeding
  • Files: TRIS
  • Created Date: Aug 23 1976 12:00AM