My NTRIP service (I use the free California Real Time Network for my very occasional amateur surveying) recently changed its datum from Epoch 2017.50 NAD83(2011) to Epoch 2025 NAD83(2011). They also upgraded to RTCM3.3. Will this affect the accuracy of my Lat/Long positions? I don’t see anywhere to program the datum, either in my RTK Express or in SW Maps. I tried using it home and I received location coordinates but looking at the aerial photograph in SW Maps, the non-RTK position appeared about 1.5’ closer than the RTK corrected position. However this doesn’t mean much since the aerial photograph can not be registered (i.e. located) properly.
I just updated the firmware in the RTK Express from 3.1 to 4.4 with no problems. I am going to update the firmware in the ZED-F9P next (It has been a couple of years since I used the RTK Express) as soon as I download the utilities from ublox.
The problem with infrequent use is that I have to relearn everything that I researched previously.
[Edit] One last thing, I was able to update my ZED-F9P firmware to 1.32. I noticed that there is a 1.51 Firmware that has L1/L2 in the name of the of the firmware where my previous firmware did not. Is 1.51 compatible? My ZED-F9P is a 2021 model or thereabouts.
But seriously, NAD83 is more or less fixed to the North American plate, and parts of California are on the Pacific plate, and parts have significant deformation.
Aerial imagery and non-RTK positions are almost certainly unreliable and you should not pay attention to either in precise work. My only advice is to dig in to the details published by California to understand what they really mean, and in particular to understand velocities (in NAD83(2011)) of crust-fixed monuments.
In Massachusetts, coordinates are all in NAD83(2011) epoch 2010.0.
If you are trying to be serious, presumably you have measured a number of points that you expect to be stable, and you can remeasure them with the new RTN data, and see how they differ.
In the open source world (which SW Maps is not part of), the standard approach for dealing with datums is proj, and the EPSG database. There is a datum code for NAD83(2011) epoch 2010.0, EPSG:6319, and then you’d need to process the data with a different datum tag. That would probably lead you to realize that proj doesn’t really support epoch dates for NAD83, and that dealing with coordinates in an area with deformation due to plate motion is very difficult.
Thank you for the advice. As I said I use this equipment only a few times and it takes me a few days or weeks to get everything clear in my head. It finally came to me that the CRTN is broadcasting its reference stations with a new lat/long reference so my points using the same reference station will move the same amount. They did link a tool to change the new measurements to different datums/epochs.
I had been thinking that I needed to update either SW Maps or the ZED-F9P to know what datum/epoch that I am using but they really don’t care. I just need to note the datum/epoch of my measurements so I can convert if I want to find an existing benchmark that has been located with a different datum/measurement.
Just a note to say that I did update my ublox firmware to 1.51 with no problems. I have been very impressed with the RTK Express being so accurate and able to take updates (e.g. firmware update from 3.1 to 4.4 and ublox ZED-F9P update from 1.1 to 1.51) with absolutely no problems. The value proposition of this device is quite good!
Yes, state-provided RTK networks will be required or strongly encouraged to update to the new NGS reference frames (like NATRF2022) because the National Geodetic Survey (NGS) is modernizing the National Spatial Reference System (NSRS) and phasing out older datums like NAD83, meaning all federal, state, and private users need to align for accuracy, with mandatory adoption expected for government mapping and strong pressure for others to follow to prevent significant shifts in coordinates and data.
Why the Change is Happening
Modernization: The NGS is replacing NAD83 and NAVD88 with dynamic, plate-tectonic-based frames (like NATRF2022 for North America) that account for Earth’s movement, providing a more accurate, long-term system.
Federal Mandate: All federal agencies must adopt the new datums, setting a precedent for states and local entities.
State & Local Adoption: States with RTK networks (like Iowa’s RTN) are expected to follow, requiring updates to their systems to broadcast in the new frames.
User Impact: Precision agriculture, surveying, and engineering will see GPS-defined boundaries and lines shift by several feet if not updated, potentially causing auto-steer to drift or features to appear in the wrong place.
What to Expect
Transition Period: There will be a period where both old and new datums are supported, but the move to the new system is inevitable.
Data Conversion: Users will need to update software and reprocess data to align with NATRF2022 and NAPGD2022 (for heights) to maintain accuracy.
In essence, while not always a “hard” mandate, the functional necessity of staying aligned with the federal standard and avoiding significant positional errors means that state RTK networks and their users must update to the new NGS reference frames.
Absolutely true for all positions. Your previous work will still be “good”, as long as the reference frame is noted with the positions.