skip to content
MODIS Image
Cofrin Center for Biodiversity

•  GPS & GNSS  •

The term "GPS" is commonly used to refer to equipment and methods associated with satellite navigation, but recent developments have rendered that term obsolete. Satellite navigation today utilizes information from multiple satellite networks including our old GPS system, the Russian GLONASS system and the European Union's Galileo program. The combined systems are referred to collectively as the Global Navigation Satellite System (GNSS). That being said, we plan to stick with the old terminology. Hopefully our audience will know what we're talking about.

GPS For Mapping (vs Navigation)
Most encounters with GPS involve navigation. We frequently see hand-held or dash-mounted receivers being used to get from one place to another. However in our work we are primarily interested in the mapping capability of our GPS equipment. We use the technology to capture locations associated with field observations. The equipment and methods used for a particular GPS mapping project depend on a variety of technical and practical considerations. Since the results of GPS mapping work wind up in the scientific record, the error control and data integrity requirements are more rigorous than those for navigation.

Handheld Receivers
Using a handheld receiver to record the spatial aspects of field observations is a common approach. The accuracy required by the study determines the technology to be used.

  • Recreation-grade equipment will get the job done the great majority of the time.
  • Submeter technology is the next step up in accuracy. The equipment is very expensive and the specified accuracy is only achieved when prescribed methods are followed. The decision to use submeter technology on a project should be carefully considered.

Tracking GPS
Sometimes the GPS receiver travels with the research subject rather than the observer.