GlobalPositioningSystem

From GNU Radio
Revision as of 01:40, 21 March 2017 by Devnulling (talk | contribs) (Fix formatting - html entities)
(diff) ← Older revision | Latest revision (diff) | Newer revision → (diff)
Jump to navigation Jump to search

Global Positioning System (GPS)

GNU Radio can be used to create GNSS receivers. The DBSRX daughterboard for the USRP is capable of receiving signal from all contemporary GNSS systems.

Requirements

  • For civilian accuracy, the equivalent of $100 GPS receivers, the signal of interest (C/A) is at 1575.42MHz(L1) with a bandwidth of ~2.046MHz.
  • For surveying accuracy, the signals of interest (C/A & P (Y)) are at 1575.42MHz(L1) and 1227.6MHz(L2) with a bandwidth of ~20.46MHz at each frequency.
  • For military accuracy, you have to add the restricted decrypting hardware on top of the surveying requirements.

The Complete Specification

  • U.S. Coast Guard Website (This looks like where civilians should go)
  • GPS Support Center Website (Less flashy website for U.S. military GPS users?)

Links to papers with details about software GPS implementations

Overview of GPS Operation

General GPS Information

  • http://gpsinformation.net/
  • A decent introduction to GPS, and even better, SDR implementations thereof, is "Fundamentals of Global Positioning System Receivers: A software approach", by James Bao-Yen Tsui (ISBN 0-471-38154-3).
  • http://gpstrackit.com/blog/
  • A regularly updated blog on the applications of GPS and GIS technology

SBAS/WAAS/EGNOS/MSAS information here

OpenGNSS Community Information

Projects

The Russian GLONASS

  • http://www.glonass-ianc.rsa.ru/pls/htmldb/f?p=202:1:12061333542270124939 The Russians added needless complications when they selected a silly time-scale for their system and decided to share the spreading codes between satellites. GLONASS also consumes a lot more bandwidth. However, this would be an excellent demonstration of an SDR's adaptability, since a working software GPS receiver has all the necessary components that a GLONASS receiver requires. One just rearranges them differently. GALILEO falls into the same category.

Q&A

Q: What about DGPS for GPS positioning accuracy improvement?

A: For the continental US, WAAS is more reasonable. The marine DGPS beacons that operate at LF (~300kHz) would require another RF path and related antenna.

Q: What about WAAS, EGNOS (Europe), MSAS (Japan / Asia) for GPS positioning accuracy improvement?

A: WAAS is broadcast on the same L1 frequency as GPS itself. So WAAS support is a pure software feature.