Performance Trials of an Integrated Loran/GPS/IMU Navigation System, Part 1

Abstract

The Federal Aviation Administration (FAA) is currently leading a team consisting of members from Industry Government, and Academia to provide guidance to the policy makers in their evaluation of the future of Loran-C in the United States. In a recently completed Navigation Transition Study, the FAA concluded that Loran-C, as an independent radio-navigation (RNAV) system, is theoretically the best backup for the Global Positioning System (GPS). However, in order for Loran-C to be considered a viable back-up system to GPS, it must be able to meet the requirements for non-precision approaches (NPA's) for the aviation community, and the Harbor Entrance and Approach (HEA) requirements for the maritime community. Through FAA sponsoring, the U.S. Coast Guard Academy (USCGA) is responsible for conducting some of the tests and evaluations to help determine whether Loran can provide the accuracy availability, integrity, and continuity to meet these requirements. A major part of assessing the suitability of Loran is in understanding the nature of Loran ground wave propagation over paths of varying conductivities and terrain. Propagation time adjustments, called "additional secondary factors (ASFs)," are used to adjust receiver times of arrival (TOAs) to account for propagation over non-seawater path(s). These ASFs vary both spatially and temporally, and unless understood and/or modeled, we lose accuracy and may not be able to guarantee a hazardously misleading information (HMI) probability of less than 1x10-7. The Coast Guard Academy has been conducting a series of tests on a new integrated Loran/GPS/IMU receiver in the Thames River. This receiver integrates IMU information (velocity and acceleration) and ASF data from a stored grid into the Loran position solution to improve the accuracy and consistency of the resulting position. The density of the ASF grid used is base

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Document Details

Document Type
Technical Report
Publication Date
Jan 27, 2005
Accession Number
ADA575159

Entities

People

  • Gregory Johnson
  • Peter Swaszek
  • Richard Hartnett
  • Ruslan Shalaev

Organizations

  • United States Coast Guard Academy

Tags

Communities of Interest

  • Biomedical
  • Materials and Manufacturing Processes

DTIC Thesaurus Topics

  • Accuracy
  • Angular Acceleration
  • Coast Guard
  • Electrical Engineering
  • Failure Mode And Effect Analysis
  • Filters
  • Inertial Measurement Units
  • Interpolation
  • Kalman Filters
  • Loran
  • Measurement
  • Navigation
  • Radio Navigation
  • Radio Navigation Systems
  • Rhode Island
  • United States Coast Guard Academy
  • Urban Areas

Readers

  • Aviation Safety and Air Traffic Management
  • Inertial Navigation Systems.
  • Systems Analysis and Design

Technology Areas

  • Space