What is “survey grade accuracy”?

There are numerous tasks and projects in which accurate measurement of 3D points is critical. A few examples might be mapping, construction, communications, and ownership boundaries and other civil law applications.

v\:* o\:* w\:* .shape Normal0falsefalsefalsefalseEN-USJAX-NONE/* Style Definitions */table.MsoNormalTable{mso-style-name:"Table Normal";mso-tstyle-rowband-size:0;mso-tstyle-colband-size:0;mso-style-noshow:yes;mso-style-priority:99;mso-style-parent:"";mso-padding-alt:0in 5.4pt 0in 5.4pt;mso-para-margin:0in;mso-para-margin-bottom:.0001pt;mso-pagination:widow-orphan;font-size:12.0pt;font-family:Cambria;mso-ascii-font-family:Cambria;mso-ascii-theme-font:minor-latin;mso-hansi-font-family:Cambria;mso-hansi-theme-font:minor-latin;}The degree of accuracy that would be expected in such projects depends on the final application and intended use of the survey or mapping data. The acceptable could be a foot or more away from its actual surveyed location, and in some projects, the maximum acceptable error is only two to three inches or less. According to the USGS Global Navigation Satellite System Committee it is the surveyor's responsibility to know the accuracy requirements of the survey and match this with the accuracy of his or her receiver in combination with the accuracy of the correction information being received based on correction quality and location. Most survey grade equipment has horizontal and vertical accuracy based on distance. Therefore when roving in RTK mode the vertical accuracy of the surveyed points in relation to the base station 8 km away is 2 cm + 1.6 cm or 3.6 cm. The further a survey is from the correction information, the less accurate the survey.

Traditionally, a professional land surveyor must be both accurate and precise, and as you might expect, reaching survey grade accuracy by manual field-survey measurements can be extremely time consuming -- not to mention, on inaccessible and uneven terrain, dangerous!

At DroneView Technologies, we pride ourselves on refining our aerial mapping data to the point that it meets the standard of American Society of Photogrammetry & Remote Sensing (ASPRS) Positional Accuracy Standards for Digital Geospatial Data (2014). With properly placed reference points (another blog to come on this topic later!), we can generate point clouds with a Root Mean Square Error (RMSE) of 3 to 5 cm (xyz) when compared to field surveyed ground control and check points. With drones, we can rival the accuracy of traditional mapping methods while bringing an innovative level of speed and safety to the table.

For more information, contact DroneView Technologies. Aerial Data Acquisition and Processing: Full Service. Trusted Solutions.