ERM LLC recently acquired a set of 20 AeroPoints, which allow us to place our own ground control points for photogrammetry surveys. With this new equipment, ERM can provide survey-grade accuracy without any assistance from the customer. Just tell ERM where you need data, and we can have it for you within days.
We checked the X-Y-Z accuracy of the AeroPoint system against a GPS and Vertical Control point in the National Geodetic Survey, Cooperative Base Network Control Station AJ8025. An Aeropoint was placed directly on top of AJ8025 for one hour. The AeroPoint report showed that the marker came within one inch of AJ8025’s X, Y and Z. We will add data to the table below as we acquire it. Keep in mind that some human error exists in placing the AeroPoint directly over the mark.
| Mark | Maryland Easting (m) | Difference (m) | Maryland Northing (m) | Difference (m) | NAVD88 Height (m) | Difference (m) |
| AJ8025 | 372,840.628 | 180,567.353 | 178.221 | |||
| AeroPoint 4/23 | 372,840.630 | 0.002 | 180,567.329 | -0.024 | 178.237* | 0.016 |
| AeroPoint 4/26 | 372,840.622 | -0.006 | 180,567.348 | -0.005 | 178.255* | 0.034 |
| AeroPoint 5/6 | 372,840.610 | -0.018 | 180,567.319 | -0.034 | 178.219* | -0.002 |
| AeroPoint 5/11 | 372,840.621 | -0.007 | 180,567.342 | -0.011 | 178.235* | 0.014 |
| RMS Error (m) | 0.010 | 0.022 | 0.020 | |||
| RMS Error (in) | 0.400 | 0.853 | 0.776 |
* 1.2 inches were subtracted from the AeroPoint report Height to account for the thickness of the marker.
Updated 5/11/17.
