Are pilots that fly the RTK for surveying connecting to Ntrip servers (custom network) for corrections or not?
If so what are the favorite ones based in the US?
If I were to use the D-RTK2 do I need to connect to a Ntrip server (custom network) or not?

I use WVCORS - West Virginia Continuously Operating Reference Stations, which is managed by the Department of Highways. You can go to the NGS website to see what is in your area.  I haven't and probably won't use the D-RTK2 base until mode 3 ( I think that is the right term) is fully functionally. Until then, you need to set the D-RTK2 on a known point. When mode 3 is working, you'll need to access a nearby CORS station to get RTCM message for a good fix.

i use both of them... but i prefer drtk2. First i usually fix the coordinates of drtk2 with ntrip servers here in argentina, but you can use P4RTk with drtk2 without connecting to any other server, just between them (p4rtk + drtk2)

Skyveyor112 Posted at 2019-12-29 17:07
I use WVCORS - West Virginia Continuously Operating Reference Stations, which is managed by the Department of Highways. You can go to the NGS website to see what is in your area.  I haven't and probably won't use the D-RTK2 base until mode 3 ( I think that is the right term) is fully functionally. Until then, you need to set the D-RTK2 on a known point. When mode 3 is working, you'll need to access a nearby CORS station to get RTCM message for a good fix.

Hi,

before it will be possible to use the 4G dongle inside the D-RTK2 Mobile Station (*) to get NRTK/NTRIP corrections, another possible solution could be:
1) setup and use the 4G dongle and NTRIP corrections in the P4RTK Remote Control using the DJI GS RTK app (Custom NTRIP mode)
2) put the P4RTK on the ground on top of the reference point to get its corrected x,y,z coordinates (AIRCRAFT);  z  must be corrected for the P4RTK antenna fase center height above the point (**)
3) put the D-RTK2 on top of the reference point
4) set the DJI GS RTK app in D-RTK2 mode; link the Remote Control with both the D-RTK2 and the P4RTK
5) input in the DJI GS RTK app the correct coordinates of the reference point (z must be corrected for the D-RTK2 antenna height above the point - 1.802m)
6) start the flight

Absolutely not "elegant" but in theory it should work.

Maurizio

P.S.
*  After D-RTK2 firmware update v02.02.0014 (2019.09.16)  Mode 3 became functional. Althoug the use of a 4G dongle inside the D-RTK2 receiver is not implemented yet, the D-RTK2 can receive RTK corrections through the P4RTK Remote Controller. See this link for more details.
**  I am not sure if the the DJI GS RTK app shows the "GNSS antenna" coordinates or the "camera sensor center" coordinates, but the former is the most probable.

First, I've found the D-RTK 2 to be a very expensive lawn dart.  When it comes to precise location, it's just OK, and as the Verizon commercials say, "just OK is not OK".  I connect to my local CORS network for RTK, and I've found that - other than the elevation errors due to ellipsoid-vs-geoid, but that's for another thread - it gets me to within one inch accuracy.  That's because the CORS stations "know" where they actually are, irrespective of the GNSS errors that are always present and always variable.  So they can correct for true position vs. whatever the GNSS thinks it is.  The D-RTK 2 can only average a bunch of the current GNSS coordinates, all of which have the variable error.  In other words, it doesn't know where it is; it only knows where the GNSS signals think it is, and those signals have an error.  So educated and reasonable people can disagree, but my position is, ditch the DRTK-2, and stick with an NTRIP like CORS - whether via RTK or PPK.

jdzac Posted at 1-28 13:23
First, I've found the D-RTK 2 to be a very expensive lawn dart.  When it comes to precise location, it's just OK, and as the Verizon commercials say, "just OK is not OK".  I connect to my local CORS network for RTK, and I've found that - other than the elevation errors due to ellipsoid-vs-geoid, but that's for another thread - it gets me to within one inch accuracy.  That's because the CORS stations "know" where they actually are, irrespective of the GNSS errors that are always present and always variable.  So they can correct for true position vs. whatever the GNSS thinks it is.  The D-RTK 2 can only average a bunch of the current GNSS coordinates, all of which have the variable error.  In other words, it doesn't know where it is; it only knows where the GNSS signals think it is, and those signals have an error.  So educated and reasonable people can disagree, but my position is, ditch the DRTK-2, and stick with an NTRIP like CORS - whether via RTK or PPK.

Agree with you Jdzac. That's why we need the possibility to survey points in the ground with the DRTK2 and Cors network, so we can define precise base station near the field where to mount the DRTK2,  without carrying another GPS (wich i do usually)

I second what jdzac said- we use our DRTK-2 with NTRIP rather than standalone whenever possible. We either use our own NTRIP caster (we have an unofficial CORS station) or the California Realtime Network (CRTN). No dongle needed, we use a hotspot for network connection (although a dongle would make things simpler).