Establishing Benchmark On Remote Island

Hello,

How would I go about establishing a new benchmark where there’s no known points, no CORS network, no base stations, no mobile signal etc. etc.?
It’s as middle of nowhere as nowhere can get.
The only thing I’ll have access to is 2 Reach RS2+ units, tripods, tribrach, tape.

Additionally, while I’m performing the static occupation to establish the benchmark, can I connect to the unit via LoRa radio with my other RS2+ unit to do rapid static occupations elsewhere, or will I need to calculate my benchmark position first before I can take measurements relative to it?

My measurements need to end up in the UTM co-ordinate system, so I can’t just make up benchmark coordinates.

I’m used to surveying with RTK corrections using Leica systems with good access to the UK CORS network, so setting up benchmarks is new to me.

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I believe the NRCAN PPP service can be used globally? There may be better options for you specific location. I’m not very familiar with workflows outside the US.

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Yes, Precise Point Positioning can be used globally. Some of the latest PP software has this function as it uses satellite ephemerides. Our Javad Justin 3 PP software has this capability .

You can use several online services as Michael quoted (AUSPOS or NRCAN). Make sure you have adequate observation times (minimum of 4 hours per observation) and remeasure on a different day or two to compare with the first solution. You can then average both coords for your final solution if needed

You can use the preliminary coords that the base derives for local radio RTK, but if it was me, I’d rather use the final computed coords then start RTK. You can use the preliminary base coords and then translate all your rover and base to the final coords.

Have fun !

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But, why? (sincere question)

By all means, use the PPP tools to try and reference UTM as precisely as you can. Although, I have to question the necessity for such precision. Of course I don’t know if you are trying to land a returning space vehicle on a precise point, or what, lol.

If you were to establish a point the best you can and then reference all of your work to that point, you would probably be fine. If there is anyone else working on the project, they could simply use your point and tie right in with your work. And you could tie back in at a future date as well.

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Is this your location? :crazy_face:

-54.4220°, 3.4130°

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This would be my guess… I’d go a long way for a good pie but…

WVGX+WJQ, Adamstown PCRN 1ZZ, Pitcairn Islands

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But why, lol. Danger Will Robinson. They are not only new to Emlid but obviously in setting up control networks and setting up an arbitrary network can go sideways real quick. I definitely wouldn’t have others tieing into it.

Oh and inside joke I have the Evo 2 sitting next to me, lol. They are going to pay me to get them running.

Thank for the responses (particularly @EBE111057 and @michaelL )

I’d seen PPP as the only option left to me (here:placing-the-base ), but when presenting this to the guy running the show they were insistent that PPP wasn’t an option, and that there were other equally accurate methods available (and then seemed to basically describe PPP, and insist it was different?).

Being new to this myself, I figured I’d double check what the right move was here, and that if there was anything different to PPP that it would be suggested.
As far as I can see from your responses, it looks like PPP is what I want though to get the most accurate measurements.

As to why it can’t be an arbitrary network - I’m just following a brief, and the scientists want UTM for whatever they’re up to :woman_shrugging:. Probably tying it into bathy data or something

Pitcairn is a good guess :zipper_mouth_face:

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Can the guy “running the show” provide whatever data is in UTM to tie into?

Very unlikely, and if so it would probably be months down the line to get signed off.

Anyway, unless there are other suggestions for solutions, I’m just going to treat this thread as answered as I don’t have any other details I’m allowed to provide.

Thanks!

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Here’s a great article on the PPP process :

https://cgrsc.ca/resources/gnss-augmentation/precise-point-positioning-ppp/

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Hi @Onyx,

Just wanted to confirm comments about using the PPP service. It should work fine for you. To record the logs for the PPP service, you can follow the steps from this guide.

As Bryan said, you can wait till you get precise coordinates from the PPP service. However, final ephemerids become available 13–15 days after the end of the week in which the logs are recorded. So as not to wait all this time, you can also do the survey locally with the meter-accurate position of the base. And then, when you get the coordinates from the PPP, just shift the data. The workflow is described here.

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