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Field maps and Trimble DA2 catalyst

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05-25-2023 06:01 AM
EddieWBanks
New Contributor
I am using Field Maps with a Trimble DA2 Catalyst (30 cm subscription) and manage to connect all ok, which is great. However, on its first use I had overlooked the Geoid and Ellipsoid settings in Trimble Mobile Manager (TMM) and now when I import the data into ArcGIS pro there are notable differences in x,y and z between locations recorded with a Trimble R10 RTK device. There is a difference of several meters between the R10 and catalyst in both the vertical and horizontal accuracy and I believe it is with the settings that I have used in choosing the Geoid and ellipsoid for the Catalyst. Does anyone know where the geographic coordinate information is kept in the Catalyst file? I have gone to the log file in TMM but cannot find any metadata or info. There is also no information when I download the data file in ArcGIS Online from what was captured using the Field Maps app. I also note that many of the data capture settings have to be done in Field Maps and not TMM (e.g., data acquisition interval). The data file from Field Maps also does not appear to report H and V accuracies of the Catalyst. I was using the subscription of 30 cm and H and V were around 5 and 9 metres in the data file. Does Field Maps record the accuracy of the Catalyst? Any help is greatly appreciated or guidance on where to find this information. Cheers Eddie
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6 Replies
Y_Chau
by
Occasional Contributor

Best practice with devices like Catalyst is to crosscheck with few control points before starting work. Catalyst probably works on ITRF Current Epoch which will not match with your local reference. Trimble offers several output CRS options but you should make sure that the correct positions are passed to Esri from here. I am assuming that you see close to 30cm accuracy while working but this is not stored in GNSS metadata fields in the layer. Is this the case?

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EddieWBanks
New Contributor

Thanks Chau, yes cross checking with a few control points is a great idea. Hindsight is a beautiful thing! Will definitely do this next week for the next survey. Yes there are several different CRS options and I think I overlooked this when setting up the new Catalyst as it had already been done on the previous one I was using.

I have taken a snip from the output from the Catalyst which has been generated when I upload the data collected in Field Maps to ArcGIS online. Whilst I see the reported GPS accuracy in the top bar of Field Maps in the data file the values don't seem to be correct. ie they are metres instead of cm. I would be expecting less than 50 cm with the 30 cm subscription service that I was using and where I was conducting the survey. So I am not entirely sure what these accuracy columns refer to (image below and attached)? 

EddieWBanks_0-1686047055711.png

thanks for your assistance.

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MatthewLeMaitre
New Contributor

Have you had any luck with this? I have a similar bust. Could it be the ITRF2014 to Auxiliary Sphere?

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Y_Chau
by
Occasional Contributor

@EddieWBanks From the names of the fields, these do not look like standard Esri GNSS metadata fields. How did you get these fields? Standard Esri fields should look like below.

GNSS.jpg

What is the value in "Fix Type" field for you? I want to know if the smartphone was receiving corrections via Catalyst or just using the internal autonomous GNSS. The accuracy values look more like the phone GNSS. That could also explain the shift from local control points.

Sincerely

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EddieWBanks
New Contributor

Hi Y Chau, 

Yes I just used the default settings that were provided. I see that if I go to the desktop version of Field Maps I can adjust some of these settings in the table. To me it is not clear though how Field Maps on the device is pulling the data from the Catalyst?

 

I have used both IOS and Android devices and the fix type seems to mostly 'fused'. However, sometimes you see that the vertical accuracy is better than the horizontal which shouldnt be the case. Also this was using the 10cm subscription service. I understand it takes some time to lock in but this is an area with plenty of 4G/5G phone coverage. 

Whether this is because I have been setting the collection settings to 1 sec. Although the table shows that data is not collected at this frequency generally several seconds.

If you have any suggestions that would be great

Thanks

Eddie

 

 

EddieWBanks_0-1687999720457.png

 

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EddieWBanks
New Contributor

Hi Matthew,

No not much success on this yet. I have now set the dataframe in Trimble mobile manager to ITRF2014, Geoid to EGM96 (Global) and making sure field maps is also using WGS84.

I just collected some new data last week and the downloaded data file from Field Maps shows vertical accuracies are greater than horizontal? WTF? So still not sure what and how Field Maps is capturing the data from the Catalyst.
In the top window of Field Maps while collecting data it reports the GPS accuracy, which seems to be that of the Catalyst subscription but looking at the data file it is very different.

I also require that my gps positions are collected every second, which it allows me to do so in the setup menu but it only reports the data every 2-3 seconds in the data table????. I realise that the accuracy might not be as good whilst walking along but my other gps has no issue in sending high frequency data.

If you have any suggestions that would be great on how to resolve the issue that would be awesome.

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