NTRIP only needed / used for RTK, not PPK?

I’m a new to mapping and surveying. I just bought a Reach RS2+ for recording GCP locations. My research indicates NTRIP is only used / needed for RTK operations, not PPK. Is this the case? Or do I need to access / use NTRIP for PPK operations as well? I think most or all of my work will be PPK, so it’s possible / probable I don’t need NTRIP, but I want to understand what it is. Thank You…

Hi Eric, welcome !

NTRIP is required for real-time applications only, not for PPK.
NTRIP is a protocol that allows to stream GPS corrections through the Internet. The rover has the role of a NTRIP client, retrieves corrections by NTRIP, and is able to compute its precise location in real-time this way. Very convenient to record GCPs :slight_smile:

Recording GCP locations in PPK with a single Reach RS2+ is a bit tedious in my opinion. In PPK you always use 2 receivers : 1 as the rover, 1 as the base. You have the rover only, so you have to find a public base, aka CORS, if some are available in your area. Then, you will get the GCP coordinates after a post-processing operation, for example with Emlid Studio. If your data was not good enough, you will see that the accuracy is not good only at this moment, and not in the field, which can be a problem.

Having a second receiver in your own hands may be very useful, and the workflow is pretty nit → How to correct collected points with a new base position? - Support tips - Emlid Community Forum

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Thank you for confirming NTRIP is only used in RTK operations. Luckily there is a CORS station near me. So I will access a VRS network and use my RS2+ as a rover to record my GCP locations prior to flying my drone, then use my RS2+ as a base to get corrections during my flight. I think this workflow is possible and will work? I hope to be able to buy a second receiver, probably an RX in the near future. Then I will have both a base and a rover for PPK.

Yes this workflow looks good !

Remember that only the RS2-series (and RS series) supports raw logging. The RX is a network rover only, made to small and super simple, so it does not have logging capabilities.

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If I understand correctly, after I buy a second receiver (an RX) I can use it as rover to record my GCP locations with my RS2+ as a base. Therefore I don’t need the RX to log corrections, right? The RS2+ will log corrections during my drone flight. Or perhaps I don’t fully understand yet what is meant by the term logging?

Hi Eric,

Logging capability is the feature that allows recording raw data log for post-processing. Reach RX doesn’t have it, so it works only in RTK.

As you correctly mentioned, Reach RS2+ can act as a base, while Reach RX receives NTRIP corrections in real-time and acts as a rover. It allows you to avoid additional costs on VRS network subscription. That would be a main benefit of purchasing Reach RX.

UPD: fixed some typos

I think it’s important to mention that in areas without cellular network coverage, RX cannot work as a RTK rover and will not work in PPK either.

Totally agree with it. Reach RX won’t work in remote areas without cell coverage because it uses the mobile device’s Internet for receiving corrections. For such survey sites, Reach RS2+ is still the best option: it has a LoRa radio for RTK and raw data logging feature for PPK and Static.

So it sounds like everyone is saying I should buy another RS2+ rather than an RX…

Next question is: it looks like I can get a sim card and service from a cellular provider like AT&T, Verizon, or TMobile and my RS2+ can connect directly to the internet or alternatively I can use a cellular connected tablet (ipad) or iphone to connect my RS2+ to the internet? If this is the case, I think I will end up buying a cellular enabled ipad, unless there is an advantage to just getting a sim card and putting it in my RS2+?

Yes.

Yes.

It is up to you which way is the most efficient use of resources.

Hi Eric,

In my opinion, connecting Reach to the Internet via LTE modem may be a bit easier and quicker than using an iPad hotspot. You can compare by looking these two videos: