National Academies Press: OpenBook
« Previous: Combined Use of GPS and GLONASS
Suggested Citation:"GPS and Loran-C." National Research Council. 1995. The Global Positioning System: A Shared National Asset. Washington, DC: The National Academies Press. doi: 10.17226/4920.
Page 168

Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

APPENDIX C 168 GPS/Inertial Navigation System (INS) Integration The present GPS can provide a suitably equipped user with a position, velocity, and time solution whose errors are generally smaller than those of most inertial navigation systems (INS).41 This performance is achieved in all weather, at any time of day, and under a wide range of signal availability and vehicle dynamics. Nevertheless, the integration of GPS with INS can provide a more robust and possibly more accurate navigation service than is possible with stand-alone sensors. In particular, integration may be the only way to achieve the following: • Maintain a specified level of navigation performance during outages of GPS satellite reception. • Reduce the random noise component of errors in the GPS navigation solution. • Maintain the availability of a GPS solution in the presence of higher vehicle dynamics and radio interference than can be tolerated by GPS alone. The technical basis for considering GPS/INS integration is the complementary nature of the navigation errors for each system operating in a stand-alone mode. The GPS solution is relatively noisy, but stays within its statistical accuracy boundaries (either CEP or 2 drms boundaries) over time. In contrast, inertial navigation errors are not noisy, but grow in proportion to the duration of a mission and the acceleration experienced by the system. One expects that an integrated navigation solution would perform like an inertial navigator whose errors were bounded by the GPS errors. Additional benefits as noted above are also achievable with more complex integration approaches.42 GPS and Loran-C Loran-C, originally developed by the DOD, is a low frequency (90-110 KHz) radionavigation system that is used by the civil maritime and civil aviation communities. Chains of Loran-C transmitting stations cover the continental U.S. and the coastline of Alaska, as well as the coastlines of many other nations. A Loran-C receiver normally 41 Richard L. Greenspan, GPS/Inertial Integration Overview, CSDL-P-3256 (Cambridge, Massachusetts: NATO/ Agardograph on Aerospace Navigation Systems, The Charles Stark Draper Laboratory, Inc., March 1993). 42 For an overview of the benefits of both loosely coupled and tightly coupled GPS/INS integration architectures, see: Richard L. Greenspan, GPS/Inertial Integration Overview, pp. 7-10.

The Global Positioning System: A Shared National Asset Get This Book
Buy Paperback | $61.00 Buy Ebook | $48.99
MyNAP members save 10% online.
Login or Register to save!
Download Free PDF

The Global Positioning System (GPS) is a satellite-based navigation system that was originally designed for the U.S. military. However, the number of civilian GPS users now exceeds the military users, and many commercial markets have emerged. This book identifies technical improvements that would enhance military, civilian, and commercial use of the GPS. Several technical improvements are recommended that could be made to enhance the overall system performance.

  1. ×

    Welcome to OpenBook!

    You're looking at OpenBook,'s online reading room since 1999. Based on feedback from you, our users, we've made some improvements that make it easier than ever to read thousands of publications on our website.

    Do you want to take a quick tour of the OpenBook's features?

    No Thanks Take a Tour »
  2. ×

    Show this book's table of contents, where you can jump to any chapter by name.

    « Back Next »
  3. ×

    ...or use these buttons to go back to the previous chapter or skip to the next one.

    « Back Next »
  4. ×

    Jump up to the previous page or down to the next one. Also, you can type in a page number and press Enter to go directly to that page in the book.

    « Back Next »
  5. ×

    To search the entire text of this book, type in your search term here and press Enter.

    « Back Next »
  6. ×

    Share a link to this book page on your preferred social network or via email.

    « Back Next »
  7. ×

    View our suggested citation for this chapter.

    « Back Next »
  8. ×

    Ready to take your reading offline? Click here to buy this book in print or download it as a free PDF, if available.

    « Back Next »
Stay Connected!