This is more of a testimonial.
If you have questioned how repeatable the Reach surveying system is:
I perform elevation surveys for structures in FEMA floodplains. I surveyed a property last month using a BASE, ROVER setup utilizing a NGS benchmark at an airport. I allowed the solution to become fixed and waited for an A.R. ratio of no less than 100 to start collecting data. I collected data for only 1 minute for each of two points.
I was in the same area today performing another survey and thought it would be interesteing to shoot in the same 2 points as in the previous survey, using the same parameters as before.
The results were:
-
BM Bridge
1st survey 2nd survey
lat…xx.156573…xx.156573
long…-xx.063969…-xx.063969
El. Ht…91.867…91.868 -
BM Water Meter
1st survey 2nd survey
lat…xx.158371…xx.158371
long…-xx.0638563… -xx.0638563
El. Ht…91.108…91.104
As you can see, the lat and long coords of the surveyed points were precisely the same and the elevations for BM Bridge and BM Water Meter (ellipsoid ht) differed by 0.001 meter (1mm) and 0.004 meter (4mm) respectively.
I cannot attest to the actual accuracy of these recorded numbers, but I can safely tell you that the ability of the REACH module to provide repeat precision of the data over the same survey point is generally very good.