I’m using Trimble gnss on a 140m. Dual mast cb460 all the normal 2d sensors and a pitch sensor. Machine grades perfect going one direction but when I turn around and go over the previous pass in opposite direction blade is .10sh high consistently. GPS vertical error was .03 and pdop 1.3 the other day when this was going on. What would cause this. Any help is greatly appreciated.
Is this a new problem? I use Outback RTK for surface drainage on a scraper, and varying grade like this is pretty much normal. My total system only cost about $20k, and being off a tenth really doesn't matter much to a dirt ditch with a foot of drop in a half mile.
From what you describe seems like a problem with the compass. I've seen it with Topcon on a single mast. But I'm only guessing.
No it’s not a new problem, been happening probably ever since system was new. Sitech has always thought it was something to do with 2d sensor calibration but recalibration seems to have no affect. Grade is very consistent when it’s missing. Will stay the same height off the first pass for the entire second pass. Seems there has to be something you could do to bring them together.
Are you selecting one side of the blade ? How many satellites do you receive ? Sitech is pretty good about fixing bugs like this
I know nothing, but is the sensor position offset from the blade edge in the longitudinal dimension? Logical me would think, if the sensor is not really close to over the top of the blade edge this could happen.
You could play with your vertical offset on the second pass to get it closer but shouldn’t have to strange I’ll ask my operators tomorrow if they have had this happen before
I'm having the same problem going to direction with the grader making a pass and turn around going and the grade dont match. This the first grader I have ran with trimble I was always used topcon so I'm very familiar calibrating topcon but not trimble. I have tried to find on youtube calibration for trimble not no luck.
I was told about a similar situation. When your turning the machine, the system doesn't immediately recognize what your doing. So it will typically drag the blade in the direction your turning. Topcon has an extra processor that recognizes the turn faster than Trimble or Leica. I was told this by a Topcon guy so......I will say that my Topcon system does not dig in the corners. I have over simplified this but that is the general idea.