International Civil Aviation Organization Spectrum Seminar Cairo, Egypt June 4-6, 2006 Global Navigation Satellite System (GNSS) Overview and Spectrum.

Presentación del tema: "International Civil Aviation Organization Spectrum Seminar Cairo, Egypt June 4-6, 2006 Global Navigation Satellite System (GNSS) Overview and Spectrum."— Transcripción de la presentación:

1 International Civil Aviation Organization Spectrum Seminar Cairo, Egypt June 4-6, 2006 Global Navigation Satellite System (GNSS) Overview and Spectrum Implementation

2 Basic GNSS System Core Constellations –GPS –GLONASS –Galileo (under development) Augmentation Systems –Aircraft-Based Augmentation System (ABAS) –Space-Based Augmentation System (SBAS) Uses geostationary satellites India, Japan, Europe, US –Ground-Based Augmentation System (GBAS) –Ground-Based Regional System (GRAS)

3 a b c Satellite Navigation … Basically Multilateration Multilateration: By knowing your distance from at least 3 points of known-position, you can determine your own position. For Satellite Navigation: a, b & c are satellites, and a fourth is needed to solve for clock variations.

4 Earth’s Ionosphere Actual Path Assumed Path Approach: t arrival – t transmitted ~ distance from satellite Assumes straight path of radio frequency signals Earth’s ionosphere actually disrupts/bends that path Augmentations correct for that bend using dual-frequency measurements Currently not possible directly in aircraft; some signals not protected. GNSS Ranging and Timing

5 Satellite Navigation’s Mission SBAS/GBAS Implementation GBAS SBAS/ GRAS

6 FAA288-021 Satellite Based Augmentation System (WAAS used as example) L1, L2

7 Ground Based Augmentation System (GBAS) Architecture GBAS Reference Station (Integrity Accuracy Availability) Processor GNSS Receiver VHF Transmitter Monitor Status Pseudolite

8 Planned GNSS Modernization Addition of satellite constellations –Galileo, additional GLONASS satellites –Improves user availability Addition of civil signals –1164-1215 MHz band –Facilitates user ionospheric corrections –Possible broadcast of integrity signal May limit need for external augmentations Increased power, improved coding –Better resistance to interference

9 GNSS Frequency Bands Frequency (MHz)Function 108-117.975GBAS/GRAS broadcast link 1164-1215GPS L5, Galileo E5, future SBAS, GLONASS L3 1215-1240GPS L2 (site-by-site ground use only) 1559-1610SBAS, GPS L1, GLONASS, Galileo E1

10 Spectrum Issues GNSS signals are very weak –~ 50,000 times weaker than the minimum specified edge-of-coverage DME signal Aviation spectrum managers must be constantly watching to ensure spectrum incursion from in- band/adjacent band systems does not cause interference. One example: ITU Footnotes 5.355 and 5.359 –Allow fixed service in GNSS bands in some countries –Countries encouraged to remove their names from the footnotes.