GPS under transmission lines

In general I've not had any problems, even around the high voltage transmission lines, 6 abreast, but they tend to be strung high off the ground. I did recently have issues of not being able to get initialized with my base underneath some 2 phase lines with maybe 16' of separation, but it didn't cause positional inaccuracies, just radio interference. I'd used the point a dozen times before with no issues. Only this time humidity was high following a lot of rain. Curious of others experience.

I haven't had problems with GPS under powerlines using a static observation to submit to OPUS, haven't tried RTK however. Just to show how old I am, I remember High Voltage transmission lines sure raised Hell when using Tellurometers. Does anybody even remember these?
ScottB

I've worked under them and can't say I've had problems,
I was bought up to believe in them as a not good area, but can't conclude from my work that to be the case.

Haven't used a Tellurometer under one but remember setting up the TS on a reference bar inside the tower legs on a very damp day.
The tower and lines were crackling and fizzing and I was quite happy to leave the site.

Worked around and under xmission lines a bunch with both static and rtk, literally hundreds (if not a few thousand) miles, mostly 135 and 270 kV. In general I've never had any problems with gps reception. From time to time I believe there can be some harmonic rf interference that affects the link between the dc and the receivers. Static can cause a little havoc with the screens on the dc. It was never anything that couldn't be overcome by jockeying around for position.

I would rather work around xmission lines than airports.

Zero Problems next to 500KV substation and towers for 6 months

Multi path for GPS electronics from the books i have read is most difficult for the hardware/soft to
resolve when the object causing the multi path is 100 ft +- from the rover = a large transmission tower

I have seen this next to LARGE industrial cranes in large pile driving jobs set the pile points
and go from one to another start to finish to weed out multi path points= seldom a bad point
well due diligence 1:1000

its a easy walk thru the site to detect multi path by hitting the layout once more time

can set 90 pile points in four hour and check them in one hour

Contrary to others, I've found it takes about twice as long to initialize, and re-initialize under high power transmission lines.
i just figured it was based on poor satellite geometry, but maybe newer more resilient receivers work better?

The only issue I recall was 10 years ago, we had crew chief set up the rtk base under some lines on a dry winter day, the external pac-crest radio had a 12' pole with a whip antenna. After 8 hours of he went to break down the set-up and got quite a wallop of static shock when grabbing the antenna pole.

Mark O, post: 446853, member: 11591 wrote: Contrary to others, I've found it takes about twice as long to initialize, and re-initialize under high power transmission lines.
i just figured it was based on poor satellite geometry, but maybe newer more resilient receivers work better?

I did have more trouble with our older Hiper units than the present GR series we use (3s and 5s). Not much, but the Hipers were a little more picky.

I have not had any problems with RTK under BPA transmission lines with the exception of radio coms. Not quite in the day of the Tellurometer, but I did have a Wild 2002 give up the ghost while working under a line on a typical November day in Oregon. There was enough static e in the area that even the heavy rollers were vibrating from it. On the plus side, Wild repaired the TS for free because they said it should have stood up to the conditions. Those were the days.

Javad works fine under a transmission line, as long as it's a 4 wheel drive, and has a lift kit. However, it's better to move the truck if possible. 😉 just remember to take it off the pole!
N

I'm surprised to see so many saying they've never had problems around transmission lines, I've seen all kinds of problems from them. Generally high noise on the satellite signals which translates to less precise positions and difficulty initializing RTK, and OPUS solutions with far lower percentages of observations used and ambiguities fixed than I would normally expect, resulting in higher peak to peak error estimates. With older equipment I can remember seeing a base that was set up under them and the rover couldn't initialize.

Nothing personal, but setting a high radio antenna under transmission lines for eight hours then walking up and touching it without grounding it first isn't a terribly wise thing to do.

From what I can recall, we've had no issues working under high-tension lines although initialization did seem to take longer but not by much. We are a Leica shop FWIW.

As for Tellurometers: that's long before my time but I have read about them in ancient history. From what I remember, it was important to know the wet-bulb temperature at both ends and the operator had to watch out for transpiration from grass fields under the line being shot, I think the condition was called "ground swing" or something like that...

I worked right next to the largest 500 KV switch yard in BC for 4 months with the base about 200 meters away from HV lines / massive transformers
the rover was under 500 KV power lines all day long up and next to bush line as well
Not a single issue with RTK at all
Leica gs 14 and satel UHF
fiberglass rods.

No problems at all Zero just as if we where in the middle of a empty desert
same experiences with sokkia GSR1700CSX which have a novatel gps board inside just like the Leica GS14
no problems at all.

I've not had too much trouble around overhead lines other than induced current in the scope of a K&E Paragon transit when it was parallel with the lines. This caused a spark to jump to my hand or eyebrow every time I touched the scope or looked through it.

We had an incident several years ago working inside a substation site where a Total Station was fried. We billed the client for the cost of the motherboard replacement and they never questioned it - but we won't work in a substation again. The vibration of the prism rod when it was within a few feet of the perimeter fence was a bit unnerving.

I was on a 8 section topo about 5 years ago (correction April 2011). We ran everything we could on the customer's brand new Razors. This was 'my' outfit (with an Altus rover):

There were some MAJOR giant power lines and erector set poles going through the middle of the job.

I had three brands of receivers deployed and they would all loose fix if you drove faster than 10 MPH under the lines, but if you stopped, they would refix after about 20 seconds. They would not fix if you were moving, but there was a sweet spot under 10 MPH where you could retain a fix.

I looked for abnormalities in the data, but did not see any.

So this job probably deserves a little backstory:

Customer calls and says they need an 8 section topo completed (in Western Colorado) by Monday at 10:00 am. (This was for a big wetland bank project.) It is Thursday at 3:00 pm. Can it be done? Well, if you cowboy up, absolutely! We had 6 ATV's gathered on the site on Friday, with a PF500 base and 8 rovers with 7 operators. The four-wheelers ran the edges of every ditches stopping to take five shots cross the ditch every 100 yards, holding a pole off the side of the ATV. We ran two razors back and forth through the plowed fields (see video below).

This is a video of me: https://photos.app.goo.gl/mOO4NUfedc01coKg2 (that is a PM500 and I was collecting a shot every 10 feet.)