Hello all,
I’m really new in this subject, I was wondering how I can download the data recorded in the RTK Surveyor and RTK Express + and process it, for example, have the coordinates measured on the field in an excel sheet. Do I need a software?
Any hint is really appreciated.
You can export the data from U-center https://www.u-blox.com/en/product/u-center in a variety of formats, CSV files can be directly imported into excel/google sheets/etc
Hi IngridBerru,
Did you have success with downloading and postprocessing?
I’m looking into setting up a base+rover set, and would like to confirm this is possible first.
Thank you!
What you want to do – collect coordinates in the field and use them for your project – is one of the most common use cases for these RTK devices (Surveyor, Facet, Express, etc.) So the short answer is yes, definitely.
If you want to collect the coordinates you measure in the field, I recommend to start with SWMaps. It’s a free Android app you can collect coordinate with and export for later use.
Here a discussion in the Sparkfun RTK manual: https://docs.sparkfun.com/SparkFun_RTK_ … _software/
Basically any s/w that can read the NMEA strings that the RTK devices (e.g. the RTK Surveyor, Facet, Express, etc.) transmit over Bluetooth can gather coordinates for you. This is very common industry standard and is supported by many softwares that range in cost from US$0 free to US$2000 or more. The above link describes using other softwares too.
You might want to stop reading now and work on the above first. It might be all you ever need to do.
Now, as a digression to hopefully reduce future confusion, when surveyors and geodesists use the word “post-process”, they generally mean something very different: collecting the raw GNSS observations (not coordinates but other complex information) to perform complex calculations back in the office. Surveyors and geodsists sometimes do this when they need to determine very accurate coordinates, and/or perhaps when they have no reference station to work from.
One “post processing” technique (PPP) is discussed in the SparkFun RTK manual here: https://docs.sparkfun.com/SparkFun_RTK_ … fixed-base
Thanks Toeknee, the PPP post-processing technique is specifically what I wanted to confirm.
Read through the tutorial, and this looks all doable… my experience from working for a legal survey firm in Canada is that 4hrs of data collection is the preferred minimum and would typically give consistent coordinate data.
Aheerema,
Collecting raw GPS observations and post processing them is one of my primary use cases. I’ve had reliably good success getting post-processed solutions from data I collect with my SparkFun Facet using the NR-Canada CSRS-PPP service and Australia’s AUSPOS’s differential static service. Solutions I get from the two services agree to within 1/1000th of a second of lat and lon (NAD83) and 0.2m in height. I’ve also collected data from multiple days over the same mark and submitted to CRCS-PPP and received solutions that agree to similar numbers. So it’s likely that my tripod setup error and antenna height measurement error are some of the largest sources of errors.
That’s the good news.
Two points that are less-good news, but they are both being worked on:
I use a Sparkfun Facet, and there’s not an official US NGS antenna calibration model for it yet. The Facet is in the queue to get one, but there’s apparently a backlog at the NGS. So that’s a significant error source too. And by significant, I mean when compared to 0.001 seconds of difference in the lat and lon solutions from CRCS and AUSPOS I mentioned above. So I do not believe we are talking large errors here. But apparently heights are sensitive to the antenna model; perhaps this is why I’m seeing almost 0.2m difference in the height from AUSPOS and CRCS.
I have not had much success using the US OPUS differential static service. OPUS seems to be very picky about the data it processes; about 90% of the time it aborts when I attempt to process data from my Facet. I work in the US and there are significant advantages for me to use OPUS solutions. @sparky has given me a suggestion that I haven’t had the time to try yet.
For more information:
Here’s my post about using the SFETOP106 antenna model while we are waiting for the Facet to get an official antenna model. This is clearly a work-around, and I might have the north reference point for the Facet all wrong when I use the TOP106 antenna model.
Here’s my post about OPUS not working reliably for me:
Hi Toeknee, I appreciate your experience with this gear. I have another follow-up question:
If you already have established coordinates for a point where you can set up your base (either you’ve setup previously, or published control coordinates are available), are you able to setup your base with those coordinates? And how?
Thanks!
Yes, I use the WiFi configuration web page to enter the known coordinates when I am setting up my base over a point I know the coordinates for.
I’m trying to get the SW Maps data into a usable format for my wife who uses Revit for 3d Modeling. We are going to build our house this year and would like to add the elevation information to our site plan and have a full model for future use.