Professional Land Surveyor. President at D. Woolley & Associates and Lux Subterra
Actually, as much as we want to believe, this is simply not true. The R12i GNSS instrument specifications state the RTK vertical is 15mm (presumably) at one sigma - this is 30mm (3CM=0.09') at two sigma with 10% of the measurements falling outside of the 30mm. Trimble has a vested interest in making and advertising these instruments as accurate as possible. If their tens of millions of epochs of testing could report better accuracy, they certainly would do so. A couple of parking lot shots is meaningless as to restating Trimble's testing to determine their specifications. Take Trimble's word for it before you get sued for negligence and have to write a check for damages. Check out OC CLSA videos, video 4, for more information: https://lnkd.in/g9wu8GQK
3D Specialist - because the world (probably) isn't flat | Reality Capture | Georadar (GPR)
Is sub-centimetre accuracy realistic for a GNSS topo Survey? Here we tested the Trimble Geospatial R12i GNSS positioning against the Trimble S7 total station, using Integrated Surveying and a tripod to stabilise the pole while measuring the same points with both systems. The accuracy of less than a centimetre horizontal and vertical error from a quick GNSS measurement offers a viable option to total station measurement for many project requirements. - GNSS points are 5-second observations. - Total station points are single face measurements. - Total station fixed points measured with mini-prism (100 mm prism height). - Fixed points were established with the average of two GNSS observed control points, with the pole rotated 180° between the 30-second observations to reduce the effects of any equipment imbalances. As ever, the project and environmental conditions should be suitable for GNSS measurements, and the accuracy feedback in Trimble Access should be observed. #surveying #vermessung #rtk #gnss #trimbleS7 #TrimbleR12i #TrimbleAccess #workflow #productivity #geospatial
Rob LeMoine
10mo
Surveying is all about good field procedures. Checks and balances. When performing RTK Rover Surveys; are you doing Network RTK Rover Topo/StakeOut. What NTRIP Mount Point are you using? NET_MSM3/NET_MSM4? (Full Constellation GNSS: GPS, GLONASS, GALILEO +BEIDOU) True Network RTK? Or SBL, Single Baseline RTK with only GPS/GLONASS? Not all Network RTK Providers may not provide optimal RTK Data. Most Network RTK Rover Surveyors don't understand NTRIP Source Tables, nor NTRIP Mount Points selection. Are you performing RTK Base + RTK Rover with Internal UHF Radios? How many RTK Positions, (3-15-25-30), are your Crews taking? Are they taking repeat shots: how many? 2, or 3? Can your SW, dump the RTK Fix, Re-Solve the Integer Ambiguity, then re Fix? Does your SW Average the Multiple RTK Shots; display the HRMS/VRMS Deltas? Does your SW compute Measured, Averaged Point Data? Survey Project Managers have responsibility to mentor thier proteges, thier Survey Crew Team members to collect good Topo Data, or StakeOut. Does your company establish Control Points with GNSS, then switch to Robotic TS, or Manual TS. Accuracy + Precision...
Respectfully, manufacturer's specifications aren't what is important. The right question to be asking is what is the maximum multipath one could encounter, how much does it propagate into the vertical component, and what does it take procedurally to contain multipath error within a desired tolerance. Otherwise, you just have to live with what you get. Those are the questions that one should be asking. Or, as Jesse Kozlowski, PLS(NJ) aptly states, to move 'beyond pushing buttons.'