Hiper V vs Hiper V+10 antenna model with OPUS

i have had the same problem I just use the antenna option without the 10 cm adapter and itƒ??s correct but there is for sure a problem with the antenna option with the adapter?ÿ

Does the adapter give the shape of the antenna signal a different shape perhaps? I remember seeing sketches of different antennas and why it's important to note your receiver so the vertical offset is to the center of this shape. I always assumed that maybe the adapter changed that by a different amount than just 10cm but never checked it.

With the ground plane that is probably inside the antenna assembly, another piece of metal underneath should have minimal impact on the signals.

Can you use the antenna on a fiberglass or metal pole/tripod with no warning in the manual about degraded accuracy?

I do not know for certain but it is odd that they've listed both on OPUS. I had to brush up to talk about this somewhat intelligently. When looking at NGS antenna calibration pages on their website ( https://www.ngs.noaa.gov/ANTCAL/# ), I have no clue what all of the info means...The Hiper V and Hiper V +10cm have different values for the antenna electric phase centers. I'm not saying there isn't any error in the +10cm, I am just saying it probably has a different phase center. Which means the diffirence between the 2 probably isn't exactly 10cm.

Bill93, On your point about the antenna structure, I am sure you would be correct in assuming that about the 10cm adapter but mine is only a theory as to why they may have 2 different antennas listed. What you said can't be true in all situations though because NGS has cautioned of multipathing error during bluebooking or it's "GPS on Benchmarks" campaign. Large metal objects like RR tracts, guardrails, vehicles, OHE, etc are very bad for best GPS observation results. I think it is safe to assume a 10cm metal adapter right under the receiver might have some electromagnetic effects on the signal and do some further digging in that general direction. The NGS has a video that explains multipath and antenna phase centers that was helpful for me too. https://www.ngs.noaa.gov/corbin/class_description/Reducing_Error_Sources/

?ÿ

?ÿ

I also wanted to comment on the 0.052 difference in that the original poster shows as a difference between the two test runs he observed. I've printed this page a while back from the Topcon Hiper V manual and actually have handwritten the 0.0552m on the paper before this post came up and just realized that the slant mark versus bottom mount HI may be the problem?

I have a Hiper II, which is very similar to the Hiper V, ?ÿI think.?ÿ Mine came with a little short stubby 10 cm extension.?ÿ I thought the measurement for OPUS was the bottom of the mount.?ÿ

I looked at the antenna calibrations, it looks to me like the only difference should be 10 cm.

got a reply from NGS:

?ÿ

So in theory, TPSHIPER_V+10 used with a 2.000m input height should produce the same result as TPSHIPER_V used with a 2.100m height, correct?

That would be a logical conclusion, however the two calibrations are fundamentally different. The two calibration files (attached) show unique values for the antenna phase center offsets and phase center variations. We would attribute this difference to the "nearfield?ÿeffect" of the adapter; precisely why NGS offers two separate calibrations.

A more direct comparison would be between two sessions using the appropriate code as the data was actually collected. For example, occupying a point with TPSHIPER_V @ 2.000 meters, then occupying the same point with TPSHIPER_V+10 @ 2.000 meters. In this instance, the solutions should be resolved to the same point and we would hope the heights compared favorably (within the uncertainty of the solutions).

--

I will be running some additional tests.

using a 2m fixed height tripod and the .1m adapter:

ANT NAME: TPSHIPER_V     NONE             # FIXED AMB:   70 /   73   : 96%

ARP HEIGHT: 2.100                           OVERALL RMS: 0.016(m)

EL HGT:         137.239(m)   0.009(m)               135.968(m)   0.009(m)

ORTHO HGT:         169.298(m)   0.028(m) [NAVD88 (Computed using GEOID12B)]

(datasheet elev. is 169.404, this solution is -0.106)

-0.106   I have 3 other opus shares on the point that hit at -0.013, -0.052 and -0.033. I have a hard time believing that "antenna option without the 10 cm adapter and it’s correct"

I think the other model (+10) is closer to truth.

it would appear so, see NGS reply below.

How does Topcon handle it?

When you run the two receivers together, do you get the correct answer?

When I mix match an R10 and R8 receiver together using Trimble they work and give me the correct heights, in other words if I locate a point with the R10 base and an R10 rover it gives me the same results for that point as the R10/R8 combo. No difference in height except for expected tiny errors.?ÿ

When I send a file to OPUS using Trimble I'm allowed to measure three different HI points for the R10 and I don't have to do anymore, I only have to be sure I imputed into the DC the correct measure point. Trimble corrects for OPUS from there.?ÿ

I don't know if your Topcon software does that but I would look into how they treat heights with different receivers.?ÿ

There should be a HI imbedded in the data file that will be different from the measure up. The corrected HI for that receiver.?ÿ

?ÿ

I inherited a variety of issues.  I believe the Static and RTK issues are separate and will have different resolutions.

When bringing RTK vectors into Star*Net, the heights are close to being relative to the differences in the field, but off by a small amount.

With the Carlson receiver, it all checks in the field.

Are you able to compute static files with your Topcon software?

I would see how it treats the HI issue, it does sound like OPUS has a glitch in it's antenna files.

Topcon may be correct while OPUS isn't.?ÿ

If you run that same file using Topcon software does it also show the .05m difference?

I have access to OPUS, CarlsonGNSS and Star*Net. That's it.

Here are the calibrations showing the differences:

I have successfully sent hundreds of static files from the Hiper-V to OPUS. Never tried the 100mm adapter with OPUS. If you are using the adapter, just apply the correction in your antenna height.

negative. this is incorrect and will produce an error of 5 cm.

I'm really glad I was barking up the right tree.

So NGS confirmed the Hiper V 100mm adapter causes the antenna phase center to be different. Which like you said, cannot be made up with just the HI measurement alone...if you are using the adapter you have to select that antenna configuration in OPUS.

Did you say you were going to run a static at 2m Hiper V and a static with the Hiper V +10cm adapter on the same point as a proof of concept?

Causes the phase center to be different??ÿ I'm sorry, this doesn't make any sense to me, it seems that it would make it exactly 10cm higher.?ÿ You are still suppose to measure to the bottom of the mount.?ÿ The entire thing doesn't make sense to me but maybe I'm missing something obvious.?ÿ I've never used the little 10cm pole so its a moot point to me I guess.

I was at a loss as well.

Fact-

2.100 m input height using 2.000 m tripod, the .100 m adapter and the hyper_v model will produce a solution 0.052 m different than-

2.000 m input height using 2.000 m tripod, the .100 m adapter and the hyper_v+10 model.

I thought a ground plane type antenna would negate anything happening under the antenna but that is NOT the case.

NGS has checked their models and believe them to be correct. "I tested the calibrations in OPUS using two sets of the original test data, which had been collected both with and without the standoff [.100 m adapter].  When processing data collected with the standoff in place, I used TPSHIPER_V+10 with a zero (in my case) antenna height [concrete pier].  Conversely, when using data without the standoff, TPSHIPER_V was chosen, again with a zero antenna height."

They attribute this difference to near-field multipath. see attached file.

How do you mount the antenna on a tripod with the rtk radio attached, and NOT use the .100 adapter??