I am using Surveypro 5.2. I have found when I set my base over a point of known elevation I must add 9 cm to the measured HI in order to get correct elevations at the rover.
Spectra says they can't help because "they don't have a GA to test with"
Anyone else have experience with this problem?
Jim
Sounds like a phase center modeling issue with the antenna.
Just because I'm paranoid, doesn't mean they aren't out to get me.
Jim, that is correct. The phase center is off. There are several Topcon models that do that, one is the GR-3 default.
Thanks
Can I correct it myself or do I have to send it in?
I have a gr-3 and I was unaware of this. I seem to check ok vertically on known benchmarks in the same datum and geoid, I would like to know some details on the gr3 default antenna problem.
Check the toggles on slant height versus vertical height as well...they measure from two different places on the receiver.
I am having a similar issue with Survey Pro and a pair of Topcon Hiper II. I was picking up an approx. 10cm error when measuring to "bottom of antenna mount" - when I checked the antenna parameters for that measurement point it has an "offset" of 0.112m.
So I began to reobserve points with antenna height measured to "slant measure mark" and the discrepancy all but disappeared.
I can't figure out where this "offset" would come from, why I can't modify it, or why they would have included it in the first place. But it sounds here like this isn't the only Topcon receiver with a similar problem.
It would be great if an updated antenna file or some other update would address this.
Having similar problem with hiper srs
i always have to adjust all rover shots
to sync with base
I can take a shot next to base and its almost always
off .1 feet or so
Every thing is set the same in controller
Started using 2 fixes height poles and ARP only
so as not to add other things into equation
BTW I am using a Tesla (would rather have a Ranger which I still use for my
instrumen, another story or 10) so I am thinking it might not be survey pro
At long last I found a "resolution" instead of having to use a work around to my issue.
After badgering Spectra Precision a few times 'one of the guys from engineering' suggested changing the RTK correction format to see if the one I was using was applying an antenna offset twice.
So I switched from using RTCM to using CMR+ in the survey setup in Survey Pro and the elevation issue seemed to just disappear. Switch back to RTCM, and it came right back.
Glad to have it resolved, but the seemed somewhat uncanny from engineering - struck me as being one of those things they knew about but just hadn't bothered to put out into the universe. However in the real world it translated into lots of extra observations, data manipulation and at times reobservations. That spells time and $ to me - but I wouldn't imagine they are too interested in that.
For others having similar issues something it may be worth exploring your correction format.
I found the CMR+ vs. the RTCM took care of our 0.32' V error we were getting. We are running Topcon Hiper V with Carlson Surveyor Data Collectors (survCE 3.02). I was told that the new version of survCE may eliminate this error while using RTCM. We will upgrade soon, but until then CMR+ works okay and without error.
SurveCE 4.0 Release notes state "SurveCE will now give correct elevations in base/rover in RTCM3."
This has proven to be true.
I had a similar issue on a job using my Hiper Lites and an older version of Survey Pro about a year ago. The elevation issue I ran into was about 0.27' or very close to that.
My problem turned out to be the settings for the antenna definition inside of Survey Pro. I had the correct antenna selected, but when I got further into the instrument settings, the wrong point of reference was selected. I corrected that there in the field, and the problem immediately disappeared.