Skip to main content

Geodesy is the science of the Earth’s shape, gravity, and rotation, including their evolution in time. Several techniques are used to observe the geodetic properties of the Earth, including Global Navigation Satellite Systems (GNSS), Satellite Laser Ranging (SLR), Very Long Baseline Interferometry (VLBI), and the Doppler Orbitography and Radio-Positioning by Integrated Satellite (DORIS) system. 

These space-geodetic observations also provide the basis for the reference frame that is needed in order to assign coordinates to points and objects and thereby determine how those points and objects move over time.

Learn more about these space geodetic techniques and their respective data holdings, which are archived by NASA’s Crustal Dynamics Data Information System (CDDIS).

Explore Techniques

SLR Thumbnail

SLR

Satellite Laser Ranging
SLR determines the geocentric position of an Earth satellite, allowing for the precise calibration of radar altimeters and separation of long-term instrumentation drift from secular changes in ocean topography.

Join Our Community of NASA Data Users

While NASA data are openly available without restriction, an Earthdata Login is required to download data and to use some tools with full functionality.

Learn About the Benefits of Earthdata Login

Frequently Asked Questions

Earthdata Forum

Our online forum provides a space for users to browse thousands of FAQs about research needs, data, and data applications. You can also submit new questions for our experts to answer.

Submit Questions to Earthdata Forumand View Expert Responses

Earthdata
Forum