Title: NOAA geodesy Earth ellipsoid GPS evidence at DuckDuckGo URL Source: https://duckduckgo.com/html/?q=NOAA%20geodesy%20Earth%20ellipsoid%20GPS%20evidence Markdown Content: [](https://duckduckgo.com/html/?q=NOAA%20geodesy%20Earth%20ellipsoid%20GPS%20evidence) [](https://duckduckgo.com/html/ "DuckDuckGo") ## [Global Positioning System Survey - Long Session](https://duckduckgo.com/l/?uddg=https%3A%2F%2Fgeodesy.noaa.gov%2FGEOID%2FGSVS%2Fglobal%2Dpositioning.shtml&rut=98a343a2fb6f4dd1626bd4cf679108616e05184a9a4febc835626d4f244fa9c2) [![Image 1](https://external-content.duckduckgo.com/ip3/geodesy.noaa.gov.ico)](https://duckduckgo.com/l/?uddg=https%3A%2F%2Fgeodesy.noaa.gov%2FGEOID%2FGSVS%2Fglobal%2Dpositioning.shtml&rut=98a343a2fb6f4dd1626bd4cf679108616e05184a9a4febc835626d4f244fa9c2)[geodesy.noaa.gov/GEOID/GSVS/global-positioning.shtml](https://duckduckgo.com/l/?uddg=https%3A%2F%2Fgeodesy.noaa.gov%2FGEOID%2FGSVS%2Fglobal%2Dpositioning.shtml&rut=98a343a2fb6f4dd1626bd4cf679108616e05184a9a4febc835626d4f244fa9c2) [The Global Positioning System (GPS)is one example of many Global Satellite Navigation Systems (GNSS) that provide extremely precise (~1cm) positioning relative to the **Earth****Ellipsoid**. The **Earth****Ellipsoid** is a mathematically well defined surface that, on average, best fits the form of the **Earth** (approximated by an **ellipsoid** of rotation).](https://duckduckgo.com/l/?uddg=https%3A%2F%2Fgeodesy.noaa.gov%2FGEOID%2FGSVS%2Fglobal%2Dpositioning.shtml&rut=98a343a2fb6f4dd1626bd4cf679108616e05184a9a4febc835626d4f244fa9c2) ## [Geodesy - NGS INFO - About Us - National Geodetic Survey](https://duckduckgo.com/l/?uddg=https%3A%2F%2Fgeodesy.noaa.gov%2FINFO%2Fgeodesy.shtml&rut=01dc5a3a9bc244460423ec9a32f98327aed70306f7c4cccba2e25fe71621f4e8) [![Image 2](https://external-content.duckduckgo.com/ip3/geodesy.noaa.gov.ico)](https://duckduckgo.com/l/?uddg=https%3A%2F%2Fgeodesy.noaa.gov%2FINFO%2Fgeodesy.shtml&rut=01dc5a3a9bc244460423ec9a32f98327aed70306f7c4cccba2e25fe71621f4e8)[geodesy.noaa.gov/INFO/geodesy.shtml](https://duckduckgo.com/l/?uddg=https%3A%2F%2Fgeodesy.noaa.gov%2FINFO%2Fgeodesy.shtml&rut=01dc5a3a9bc244460423ec9a32f98327aed70306f7c4cccba2e25fe71621f4e8) [**Geodesy****Geodesy** is the science of accurately measuring and understanding three fundamental properties of the **Earth**: its geometric shape, its gravity field, and its orientation in space, as well as the changes of these properties with time.](https://duckduckgo.com/l/?uddg=https%3A%2F%2Fgeodesy.noaa.gov%2FINFO%2Fgeodesy.shtml&rut=01dc5a3a9bc244460423ec9a32f98327aed70306f7c4cccba2e25fe71621f4e8) ## [How do satellite images and GPS systems confirm Earth'...](https://duckduckgo.com/l/?uddg=https%3A%2F%2Ffactually.co%2Ffact%2Dchecks%2Fscience%2Fsatellite%2Dimages%2Dgps%2Dconfirm%2Dearth%2Dshape%2D1069de&rut=56ffe25a7c63e2ceabae8669e33273fbe5c820f24a54aafbb25b4cde21301852) [![Image 3](https://external-content.duckduckgo.com/ip3/factually.co.ico)](https://duckduckgo.com/l/?uddg=https%3A%2F%2Ffactually.co%2Ffact%2Dchecks%2Fscience%2Fsatellite%2Dimages%2Dgps%2Dconfirm%2Dearth%2Dshape%2D1069de&rut=56ffe25a7c63e2ceabae8669e33273fbe5c820f24a54aafbb25b4cde21301852)[factually.co/fact-checks/science/satellite-images-gps-confirm-earth-shape-1069de](https://duckduckgo.com/l/?uddg=https%3A%2F%2Ffactually.co%2Ffact%2Dchecks%2Fscience%2Fsatellite%2Dimages%2Dgps%2Dconfirm%2Dearth%2Dshape%2D1069de&rut=56ffe25a7c63e2ceabae8669e33273fbe5c820f24a54aafbb25b4cde21301852) 2026-02-06T00:00:00.0000000 [Executive summary Satellite photographs and live **Earth** views provide direct visual **evidence** of a round planet, with full-disk images and continuous video from spacecraft and weather satellites showing a curved, bounded disk [1] [2] [3]. Independently, **GPS** and satellite **geodesy** rely on orbital mechanics and a nearly spherical reference surface — the **ellipsoid**/geoid — and the accuracy of ...](https://duckduckgo.com/l/?uddg=https%3A%2F%2Ffactually.co%2Ffact%2Dchecks%2Fscience%2Fsatellite%2Dimages%2Dgps%2Dconfirm%2Dearth%2Dshape%2D1069de&rut=56ffe25a7c63e2ceabae8669e33273fbe5c820f24a54aafbb25b4cde21301852) ## [Home [www.ngs.noaa.gov]](https://duckduckgo.com/l/?uddg=https%3A%2F%2Fwww.ngs.noaa.gov%2F&rut=59f24b2f8e4c00dab7e14fe4f44d60509c6b17a561a245503f8b446bbe02693d) [![Image 4](https://external-content.duckduckgo.com/ip3/www.ngs.noaa.gov.ico)](https://duckduckgo.com/l/?uddg=https%3A%2F%2Fwww.ngs.noaa.gov%2F&rut=59f24b2f8e4c00dab7e14fe4f44d60509c6b17a561a245503f8b446bbe02693d)[www.ngs.noaa.gov](https://duckduckgo.com/l/?uddg=https%3A%2F%2Fwww.ngs.noaa.gov%2F&rut=59f24b2f8e4c00dab7e14fe4f44d60509c6b17a561a245503f8b446bbe02693d) [**NOAA's** National Geodetic Survey (NGS) provides the framework for all positioning activities in the Nation. The foundational elements of latitude, longitude, elevation, and shoreline information impact a wide range of important activities.](https://duckduckgo.com/l/?uddg=https%3A%2F%2Fwww.ngs.noaa.gov%2F&rut=59f24b2f8e4c00dab7e14fe4f44d60509c6b17a561a245503f8b446bbe02693d) ## [The Geopotential Surface | Geopotential Datums | Research | National ...](https://duckduckgo.com/l/?uddg=https%3A%2F%2Fwww.ngs.noaa.gov%2Fresearch%2Fgeopotential%2Ddatums%2Fgeopotential%2Dsurface.shtml&rut=6e05955d8836c342076c353670fdf365cd6a2fa5cb37a0ec25992551c1cfb917) [![Image 5](https://external-content.duckduckgo.com/ip3/www.ngs.noaa.gov.ico)](https://duckduckgo.com/l/?uddg=https%3A%2F%2Fwww.ngs.noaa.gov%2Fresearch%2Fgeopotential%2Ddatums%2Fgeopotential%2Dsurface.shtml&rut=6e05955d8836c342076c353670fdf365cd6a2fa5cb37a0ec25992551c1cfb917)[www.ngs.noaa.gov/research/geopotential-datums/geopotential-surface.shtml](https://duckduckgo.com/l/?uddg=https%3A%2F%2Fwww.ngs.noaa.gov%2Fresearch%2Fgeopotential%2Ddatums%2Fgeopotential%2Dsurface.shtml&rut=6e05955d8836c342076c353670fdf365cd6a2fa5cb37a0ec25992551c1cfb917) [The **ellipsoid** is thus a convenient shape for resolving coordinates, and as a reference to the geopotential surface. In order to achieve a better fit to the **Earth's** surface, we use a physical property to describe the **Earth's** surface with more spatial details.](https://duckduckgo.com/l/?uddg=https%3A%2F%2Fwww.ngs.noaa.gov%2Fresearch%2Fgeopotential%2Ddatums%2Fgeopotential%2Dsurface.shtml&rut=6e05955d8836c342076c353670fdf365cd6a2fa5cb37a0ec25992551c1cfb917) ## [Guidelines for establishing GPS-derived ellipsoid heights (Standards: 2 ...](https://duckduckgo.com/l/?uddg=https%3A%2F%2Frepository.library.noaa.gov%2Fview%2Fnoaa%2F23416&rut=3673b59f7b51e1dc2d0d3542f595bbb58d5777d99e299a70eeee61ae769a4d3a) [![Image 6](https://external-content.duckduckgo.com/ip3/repository.library.noaa.gov.ico)](https://duckduckgo.com/l/?uddg=https%3A%2F%2Frepository.library.noaa.gov%2Fview%2Fnoaa%2F23416&rut=3673b59f7b51e1dc2d0d3542f595bbb58d5777d99e299a70eeee61ae769a4d3a)[repository.library.noaa.gov/view/noaa/23416](https://duckduckgo.com/l/?uddg=https%3A%2F%2Frepository.library.noaa.gov%2Fview%2Fnoaa%2F23416&rut=3673b59f7b51e1dc2d0d3542f595bbb58d5777d99e299a70eeee61ae769a4d3a) [The following guidelines were developed by the National Geodetic Survey (NGS) for performing Global Positioning System (**GPS**) surveys that are intended to achieve **ellipsoid** height network accuracies of 5 cm at the 95 percent confidence level, as well as **ellipsoid** height local accuracies of 2 cm and 5 cm, also at the 95 percent confidence level. See Appendix A for information about local and ...](https://duckduckgo.com/l/?uddg=https%3A%2F%2Frepository.library.noaa.gov%2Fview%2Fnoaa%2F23416&rut=3673b59f7b51e1dc2d0d3542f595bbb58d5777d99e299a70eeee61ae769a4d3a) ## [Earth ellipsoid - Wikipedia](https://duckduckgo.com/l/?uddg=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FEarth_ellipsoid&rut=885badc6fdc503f234ac1eac46f4fbbeb7c8fa9536fd93e1a766ff4106ea85f5) [![Image 7](https://external-content.duckduckgo.com/ip3/en.wikipedia.org.ico)](https://duckduckgo.com/l/?uddg=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FEarth_ellipsoid&rut=885badc6fdc503f234ac1eac46f4fbbeb7c8fa9536fd93e1a766ff4106ea85f5)[en.wikipedia.org/wiki/Earth_ellipsoid](https://duckduckgo.com/l/?uddg=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FEarth_ellipsoid&rut=885badc6fdc503f234ac1eac46f4fbbeb7c8fa9536fd93e1a766ff4106ea85f5) [An **Earth****ellipsoid** or **Earth** spheroid is a mathematical figure approximating the **Earth's** shape and size, used as part of a reference frame for coordinates and computations in **geodesy**, astronomy, and the geosciences.](https://duckduckgo.com/l/?uddg=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FEarth_ellipsoid&rut=885badc6fdc503f234ac1eac46f4fbbeb7c8fa9536fd93e1a766ff4106ea85f5) ## [Global Positioning - NOAA's National Ocean Service](https://duckduckgo.com/l/?uddg=https%3A%2F%2Foceanservice.noaa.gov%2Feducation%2Ftutorial_geodesy%2F&rut=3f3cd662159866bf9ba8f4494f999e673777ecab218d5e448fb41de7d1148705) [![Image 8](https://external-content.duckduckgo.com/ip3/oceanservice.noaa.gov.ico)](https://duckduckgo.com/l/?uddg=https%3A%2F%2Foceanservice.noaa.gov%2Feducation%2Ftutorial_geodesy%2F&rut=3f3cd662159866bf9ba8f4494f999e673777ecab218d5e448fb41de7d1148705)[oceanservice.noaa.gov/education/tutorial_geodesy/](https://duckduckgo.com/l/?uddg=https%3A%2F%2Foceanservice.noaa.gov%2Feducation%2Ftutorial_geodesy%2F&rut=3f3cd662159866bf9ba8f4494f999e673777ecab218d5e448fb41de7d1148705) [**Geodesy** is the science which makes global positioning possible. **Geodesy** is literally the science of measuring and monitoring the size and shape of the **Earth** and the location of points on its surface. **NOAA's** National Geodetic Survey (NGS) is responsible for the development and maintenance of a national geodetic data system that is used for navigation, communication systems, and mapping and ...](https://duckduckgo.com/l/?uddg=https%3A%2F%2Foceanservice.noaa.gov%2Feducation%2Ftutorial_geodesy%2F&rut=3f3cd662159866bf9ba8f4494f999e673777ecab218d5e448fb41de7d1148705) ## [NAPGD2022 Home | Beta | National Geodetic Survey](https://duckduckgo.com/l/?uddg=https%3A%2F%2Fbeta.ngs.noaa.gov%2FNAPGD2022%2Findex.html&rut=47e7e6936195dbe165615b6aba8f8fe528864c80473c50301482cba8373b3c98) [![Image 9](https://external-content.duckduckgo.com/ip3/beta.ngs.noaa.gov.ico)](https://duckduckgo.com/l/?uddg=https%3A%2F%2Fbeta.ngs.noaa.gov%2FNAPGD2022%2Findex.html&rut=47e7e6936195dbe165615b6aba8f8fe528864c80473c50301482cba8373b3c98)[beta.ngs.noaa.gov/NAPGD2022/index.html](https://duckduckgo.com/l/?uddg=https%3A%2F%2Fbeta.ngs.noaa.gov%2FNAPGD2022%2Findex.html&rut=47e7e6936195dbe165615b6aba8f8fe528864c80473c50301482cba8373b3c98) [GEOID2022 provides the connection between **ellipsoid** heights determined with **GPS** and orthometric heights used for most applications. The spatial resolution of the geoid model is 1 arcminute. The geoid heights, which are in the tide-free system, are with respect to the reference **ellipsoid** of the Geodetic Reference System 1980 (GRS80) in the ITRF2020 geometric reference frame. GEOID2022 includes ...](https://duckduckgo.com/l/?uddg=https%3A%2F%2Fbeta.ngs.noaa.gov%2FNAPGD2022%2Findex.html&rut=47e7e6936195dbe165615b6aba8f8fe528864c80473c50301482cba8373b3c98) ## [Geodesy: The Invisible Backbone of Navigation - NOAA's National Ocean ...](https://duckduckgo.com/l/?uddg=https%3A%2F%2Foceanservice.noaa.gov%2Fpodcast%2Fjan18%2Fnop12%2Dgeodesy.html&rut=acebd29dfedd0716a567f530a689e939f83a95d2f48e8ea15e56cfb306020b10) [![Image 10](https://external-content.duckduckgo.com/ip3/oceanservice.noaa.gov.ico)](https://duckduckgo.com/l/?uddg=https%3A%2F%2Foceanservice.noaa.gov%2Fpodcast%2Fjan18%2Fnop12%2Dgeodesy.html&rut=acebd29dfedd0716a567f530a689e939f83a95d2f48e8ea15e56cfb306020b10)[oceanservice.noaa.gov/podcast/jan18/nop12-geodesy.html](https://duckduckgo.com/l/?uddg=https%3A%2F%2Foceanservice.noaa.gov%2Fpodcast%2Fjan18%2Fnop12%2Dgeodesy.html&rut=acebd29dfedd0716a567f530a689e939f83a95d2f48e8ea15e56cfb306020b10) [**Geodesy**: The Invisible Backbone of Navigation **NOAA** Ocean Podcast: Episode 12 **Geodesy** is a science that covers the **Earth** itself. It's the reason we know where we are, and how we can make maps of where we are and where we want to go. In this episode, learn how this science with an unfamiliar name shapes much of what we do every day.](https://duckduckgo.com/l/?uddg=https%3A%2F%2Foceanservice.noaa.gov%2Fpodcast%2Fjan18%2Fnop12%2Dgeodesy.html&rut=acebd29dfedd0716a567f530a689e939f83a95d2f48e8ea15e56cfb306020b10) [Feedback](https://duckduckgo.com/feedback.html) ![Image 11](https://duckduckgo.com/t/sl_h)