I am having an issue with our rover and Cat D5 dozer being off from one another. Basically the design layer for both the rover and the dozer are the exact same but when we zero out the dozer it is inconsistently off. Sometimes a tenth or two and sometimes a foot. For example, we shot an inlet top at a design elevation of a 20 and the rover showed we were within a tenth. However, when we began running the dozer next to the box, the blade was 11 inches higher than the box. We set up a total station to check the elevations of the blade and the rover. The rover was within a tenth of what it called out but the blade was way off. The design on the dozer showed an elevation of 20 but when we zeroed out the machine and shot the bottom of the bald it was at a 29. We re calibrated the sited but it stayed the same. We are having these issue on multiple jobsites with different equipment, networks, gps equipment. Any idea what is going on?
interesting.... Is it possible the relationship data between the blade and the on board GPS is simply incorrect? (I know nothing about this stuff, but if it's endemic, it's not just a survey issue.)
Can you set the rover on the dozer height to zero and check it with the total station? Sort of eliminate the dozer for a check??
You need to check your vertical guidance method if you are using a Trimble machine system. I'm assuming here your machine measure up is good. The guidance method does several different things in different modes. It could be a very long explanation that I would be glad to discuss, but if you're not using Trimble it would be all for naught....
Sorry, just re-read the title and see you are using Trimble. I believe you need to call your dealer and have them check the measure up. if its good, then have them show you the different vertical guidance methods and explain them to you. To get a good check on what the tractor is doing try and check it on a flat surface like a building pad. If this image shows up, it will show you how a tip of a blade can be off grade and the majority of the blade is cutting the correct plane.
Image didn't work. Go to the 5:00 mark in the video, he briefly goes through the vertical guidance.
https://www.google.com/url?sa=i&rct=j&q=&esrc ="s&source=images&cd=&cad=rja&uact=8&ved=0ahUKEwjBhtP_ttHTAhWEwiYKHcZFDokQjRwIBw&url=
2"
First thing to check is the coordinates. Measure the coordinates at the corners of the blade with your rover and then note them down from the machine panel. It may be that your level is good but E and N not.
If it is a single mast then drive straight ahead for 5-10 metres immediately before the test.
If the coordinates are all good then note the design enz at a problem position and check the models.
The position of the blade reference points will affect the reporting of cut/fill as said above but the coordinates should be independent.