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MSAS Signal Structure

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Title MSAS Signal Structure
Edited by GMV
Level Basic
Year of Publication 2011
Logo GMV.png

The MTSAT Satellite Augmentation System (MSAS) is the Japanese Satellite Based Augmentation System (SBAS) System:[1] a GPS Augmentation system with the goal of improving its accuracy, integrity, and availability, and that uses the Multifunctional Transport Satellites (MTSAT) owned and operated by the Japanese Ministry of Land, Infrastructure and Transport and the Japan Meteorological Agency (JMA).[2]

First tests were accomplished successfully, and MSAS system for aviation use was declared operational in September 27, 2007,[3][4][5] providing a service of horizontal guidance for En-route through Non-Precision Approach.[1][3][6]

MSAS Signal Structure

Signal characteristics are compliant with ICAO SARPs:[6][7]

  • Frequency ; L1 = 1575.42MHz.
  • Bandwidth ; L1 ±2.2 MHz band.
  • Data Rate; 500 symbols per Second, 1/2 convolutional encoded with a Forward Error Correction (FEC) code (250 effective bits per second).
  • Signal strength on the earth surface >-161dBw at 5 degrees elevation.

The future lines of improvement of MSAS signals are:[6]

  • Band width expansion for L1.
  • L5 signal (preparation for Dual-Frequency operations).
  • Compatibility & Interoperability achivement between the different SBAS and GNSS constellations.

For an introduction on the signal structure, please refer to the article The EGNOS SBAS Message Format Explained.



  1. ^ a b MSAS Current Status, Japan Civil Aviation Bureau, Second Meeting of the International Committee on Global Navigation Satellite Systems (ICG) organized by the International Space Research Organization, Bangalore, India , 5 - 7 September 2007
  2. ^ Multi-Functional Transport Satellite in Wikipedia
  3. ^ a b QZSS / MSAS Status, CGSIC –47th Meeting ,Fort Worth, Texas September25, 2007, Satoshi KOGURE, Japan Aerospace Exploration Agency, QZSS Project Team
  4. ^ Eric Gakstatter, Perspectives - Late April 2008, GPSworld, April 15, 2008
  5. ^ Multi-functional Satellite Augmentation System in Wikipedia
  6. ^ a b c Overview of MSAS, Presentation for ICG-3, 2008
  7. ^ ICAO Standards and Recommended Practices, Annex 10, Volume 1 Radio Navigation Aids, July 2006