Land Surveyor

WHY GPS IS NOT PERFECT

Selective Availability: the intentional degradation of the timing and position information transmitted by a GPS satellite

PDOP: (the position dilution of precision); describes the amount of error due to the geographic position of the GPS satellites.

Multipath: an error caused by a delay in the signal due to reflections from the surfaces before reaching the receiver.

DGPS: (differential GPS); a method of using a ground based correction in addition to ย the satellite signals to determine position.

  • In normal everyday use accuracy of GPS is around 10-15 meters.
  • This is because of different factors causing delays in the transmission.
  • The biggest source of error was intentional.
  • The united states introduced selective availability to make the signal less accurate so that no one could use the GPS against the united states.
  • Selective availability introduced two errors. ย 

TYPES OF ERRASย 

  • In normal everyday use accuracy of GPS is around 10-15 meters.
  • This is because of different factors causing delays in the transmission.
  • The biggest source of error was intentional.
  • The united states introduced selective availability to make the signal less accurate so that no one could use the GPS against the united states.
  • Selective availability introduced two errors. ย 

SELECTIVE AVAILABILITY

  • In 2000, the United States decided to turn the selective availability off.
  • They also announced that they do not plan to make future satellites with the feature.
  • However the public GPS will still be less accurate than the military's.
  • The arrangement of satellites can have an effect on determining position.
  • The further satellites are spread out the more accurate the measurements will be
  • On the other hand the less spread out satellites are the less accurate the measurements will be.
  • MORE INFORMATION

โ˜…
โ˜…
โ˜…
โ˜…
โ˜…
Votes: 0
E-mail me when people leave their comments –

You need to be a member of Land Surveyors United - Surveying Education Community to add thoughts!

Join Land Surveyors United - Surveying Education Community

Thoughts

  • Land Surveyor

    Yep but Total Station has also lot of imperfection : mechanical axis errors, EDM calibration, verticality, instability of the tripod, refraction, etc, ... the question is not the error budget but well how surveyors can mitigate and compensate by appropriated methods these imperfection. GNSS is actually very much precise and accurate when you are mastering all the errors and use differential setup's.

This reply was deleted.

Log into community to no longer see ads

Land Surveying Guides

Our Blog Sitemap

 
 

Explore Surveying Locally

USA Surveying Forums
Asia Surveying Forums
Africa Surveying Forums
Middle East Surveying Forums
European Surveying Forums
South American Surveying Forums
Oceania Surveying Forums
Surveying Equipment Support Forums
Search Survey Photos
Add Posts, Surveying Photos, Videos and Articles to the Surveyor Community
Add Stuff to Community

 


 
 
 

 

 

Latest in Surveyor Community

Justin Farrowโ€™s photo was featured in Surveyors Online Toolbox
GlobeZilla User Guide
Welcome to GlobeZilla, an interactive tool that lets you project custom equirectangular maps onto a 3D globe, adjust settings like rotation speed, background, and size, and even create GIFs of your globe in action. This guideโ€ฆ
Wednesday
Justin Farrowโ€™s photo was featured in Surveyors Online Toolbox
ย 
Overview of the Historic Land Surveyor Locations from a Land Surveyor's Perspective
The Historic Land Surveyor Locations page provides an interactive map of significant landmarks related to surveying history across the world. By integratingโ€ฆ
Wednesday
Jennifer Reeder is now a member of Land Surveyors United - Surveying Education Community
Wednesday
Chris Wall and Sabinus Chinenye Ugwuanyi joined Land Surveyors United - Surveying Education Community
Land Surveyor Land Surveyor
Tuesday
Joshua Parker and Frederic Cann joined Land Surveyors United - Surveying Education Community
Land Surveyor Not a Surveyor
Sunday
Episode 235 - Dr. Tony Nettleman, Attorney, Educator, Author, Speaker & Mentor via GeoRadio- All Land Surveyor Podcasts in One

Such an interesting conversation! The guys were joined this week by the one and only Dr. Tony Nettleman. Tony is a Land Surveyor, Real Property Attorney, Author, Speaker, and Educator, who has been practicing for over 25 years. Dr. Nettlemanโ€ฆ

Sunday
Justin Farrowโ€™s discussion was featured in Continuing Education
Ethics courses, while commonly required as part of the Continuing Education (CE) for Professional Land Surveyors, differ in terms of the specific requirements, the number of hours, and how these courses are integrated into the overall CEโ€ฆ
Nov 12
Justin Farrow favorited Justin Farrow's discussion Exploring How US States Differences for Ethics in Continuing Education in Continuing Education
Nov 12
Moreโ€ฆ