GPS corrections are highly accurate GPS locations used to adjust your data to match more precise measurements taken by experts.
What are GPS Corrections?
Drones navigate using GPS, and most store GPS data as information attached to each photograph taken by the drone. This GPS data is used to register, or align, images so they can be stitched together in 3D models and orthomosaic maps and provide location information in final, geo-referenced models and maps. GPS can be inaccurate, and it can vary by 5 to 15 meters, due to differences in satellites, data collection equipment, reflections near the sensor, atmospheric conditions, or other factors.
For projects that require a high degree of accuracy down to the centimeter, GPS corrections can adjust the data to more accurately reflect the position at which each photo was taken.
Where Do I Get GPS Corrections?
GPS Correction files can be obtained by installing your own base stations or referencing existing GPS base stations. You can also use services that maintain networks of ground-based stations or satellite-based systems that transmit GPS error correction signals. Some examples are: real-time kinematic (RTK) GPS, the Differential Global Positioning System (DGPS) maintained by the U.S. Coast Guard, the Wide Area Augmentation System (WAAS) maintained by the FAA, and the National Geodetic Survey's Continuously Operating Reference Station (CORS) network maintained by NOAA.
These services offer GPS Correction data files that can be downloaded, and some even offer personalized data sets, which are obtained by entering your data collection date, area, and other parameters.
How Do I Upload GPS Corrections?
GPS correction files can be uploaded directly into Mapware along with images and other files. When Mapware detects you have uploaded files that are not image files, you will be prompted to review the files, and you can label them as GPS correction files or other file types.
Upload GPS correction files when you first make a new project or add them to a project later.