H-MODULATION FOR LONG ENDURANCE MARINE INERTIAL NAVIGATION

Current versions of SINS (Ships Inertial Navigation System) are capable of providing accurate navigational data over periods of several days without the need for intervening position fixes. It is desirable to provide a similar accuracy performance level for periods of several weeks. A primary factor limiting such an extension of present capability is gyro drift, especially nonstationary (ramp-like) random components in the Z (vertical input axis) gyro. Tests have demonstrated that a gyro drift monitoring technique known as H-modulation (or wheel speed modulation) can be used to bound such components of system gyro drift to levels compatible with system accuracy goals. The key to successful H-Modulation is to minimize gyro torque disturbance variations that may be induced by the required changes in wheel speed. This paper describes the H-modulation technique, the design of the associated equipment, and some test results and system accuracy simulations. Systems implementation and data processing configurations are also discussed. Applications of H-modulation other than in SINS are indicated. It is concluded that H-modulation is a cost effective approach for providing significant extensions of SINS performance.

  • Supplemental Notes:
    • Proceedings of The Institute of Navigation, National Marine Meeting, State University of New York Maritime College, Fort Schuyler, New York, 1-2 October 1974. Price $10 members; $15 non-members.
  • Corporate Authors:

    Institute of Navigation

    815 14th Street, NW
    Washington, DC  USA  20005
  • Authors:
    • San Giovanni Jr, C
    • Levinson, E
  • Publication Date: 1974-10

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Filing Info

  • Accession Number: 00126499
  • Record Type: Publication
  • Source Agency: Institute of Navigation
  • Report/Paper Numbers: Proceeding
  • Files: TRIS
  • Created Date: Nov 5 1975 12:00AM