Welcome Guest. Sign in or Signup

1 Answers

DGPS vs. LAAS

Asked by: 5398 views , ,
Aircraft Systems

What is the difference between DGPS or Differential GPS and LAAS or Local Area Augmentation System? Both appear to be a GBSS or ground based as opposed to satellite based. I know that all Garmin products are capable of receiving DGPS data but I think that is transmitted via UHF while the LAAS information is transmitted via VHF. But could I fly an LAAS approach to CAT I minimums with the 430W unit? I see there are some LAAS approaches at KEWR now and they only go to CAT I minimums.

Ace Any FAA Written Test!
Actual FAA Questions / Free Lifetime Updates
The best explanations in the business
Fast, efficient study.
Pass Your Checkride With Confidence!
FAA Practical Test prep that reflects actual checkrides.
Any checkride: Airplane, Helicopter, Glider, etc.
Written and maintained by actual pilot examiners and master CFIs.
The World's Most Trusted eLogbook
Be Organized, Current, Professional, and Safe.
Highly customizable - for student pilots through pros.
Free Transition Service for users of other eLogs.
Our sincere thanks to pilots such as yourself who support AskACFI while helping themselves by using the awesome PC, Mac, iPhone/iPad, and Android aviation apps of our sponsors.

1 Answers



  1. John D. Collins on Nov 06, 2012

    If you want to learn more about DGPS and GBAS or LAAS, read http://en.wikipedia.org/wiki/Differential_GPS and http://www.faa.gov/about/office_org/headquarters_offices/ato/service_units/techops/navservices/gnss/laas/ .

    DGPS is a generic term for Differential GPS of which WAAS could be considered a member, although mostly DGPS refers to the Coast Guard system and is used by surveyors whereas the WAAS system is totally a satellite based system,

    None of the Garmin GPS aviation navigators receive the Coast Guard DGPS. The GNS430W receives the WAAS system on the same frequency as the standard GPS (L1 – 1575.42 MHz). The WAAS correction information is operated by the FAA whereas the base GPS system is operated by the Defense Department. The WAAS system leases transponders on three geostationary satellites over the equator and they relay the correction information to the WAAS GPS receivers such as the GNS430W.

    The GNS430W has no support for ground based augmentation, so no, the GNS430W can’t fly a GLS approach.

    0 Votes Thumb up 0 Votes Thumb down 0 Votes


The following terms have been auto-detected the question above and any answers or discussion provided. Click on a term to see its definition from the Dauntless Aviation JargonBuster Glossary.

Answer Question

Our sincere thanks to all who contribute constructively to this forum in answering flight training questions. If you are a flight instructor or represent a flight school / FBO offering flight instruction, you are welcome to include links to your site and related contact information as it pertains to offering local flight instruction in a specific geographic area. Additionally, direct links to FAA and related official government sources of information are welcome. However we thank you for your understanding that links to other sites or text that may be construed as explicit or implicit advertising of other business, sites, or goods/services are not permitted even if such links nominally are relevant to the question asked.