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Carlson BRX7 and Skyplots from Rinex Files

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(@jeffca)
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Is there a way to convert Carlson .BIN files to a Rinex, specifically a .24o file that will display all constellations in a sky plot? I use RinexDesktop to convert, however, when I put the .24o through several third party apps I am only able to get the sky plot for the GPS constellations. These apps clearly show that GLONASS, Galileo, Beidou were observed during the Static Observation. It shows each individual satellite and the duration it was observed, however, none of this shows up in the sky plot.

The reason I need this information is that we run a drone mounted LiDAR with its own GNSS that needs to compare it's data with the static GNSS data from the BRX7. However, it needs the sky plots in order to effectively do this. I've tried Carlson Support with no luck.

 
Posted : 09/10/2024 12:04 am
(@dmyhill)
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They are hemispheres painted blue...

this video might help

 
Posted : 09/10/2024 4:04 am
(@dmyhill)
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Carlson has this download:

https://web.carlsonsw.com/files/knowledgebase/kbase05.php?action=display_topic&topic_id=1200

 
Posted : 09/10/2024 4:08 am
(@bm-nolan)
Posts: 18
Active Member Customer
 

Hey that's me! This should work for any Hemisphere boarded receiver (including the BRx7). If you need the latest Rinex convertor feel free to send me a message.

 
Posted : 09/10/2024 7:16 am
(@jeffca)
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I'm using the latest Rinex Desktop Converter from Hemisphere (2.0.5.0), but like I said I don't get a sky plot of all constellations from this file. I only get GPS sky plots. If I run other brand GNSS observation files data through RTK Plot or Emlid Studio I get each observed satellite. There has to be a way to see each observed satellite on a sky plot in order to see its azimuth.

See attached photo.

 
Posted : 10/10/2024 2:09 am
(@dmyhill)
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Are you saying that the lidar processing uses those little pictures to do the processing?

 
Posted : 10/10/2024 3:48 am
(@jeffca)
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No. The purpose of the pictures were to show that the only constellation in the .24o was GPS. The purpose of a skyplot is to see the azimuth location of the satellites at the time they were observed, which is crucial in evaluating which satellites to use and which ones to toss out. I was only only getting GPS.

I was actually able to solve this problem thanks to a fellow at Carlson Support. Rinex Hemisphere does not automatically generate the extensions for the other constellations. If you generate a .24o in the same manner as in the video you will only end up with a GPS based Rinex. Perfectly fine for OPUS, which only uses GPS constellations anyway. However, in order to have all constellations in a .24o generated by Rinex Hemisphere you need to create the navigation Data file for each constellation with the following extensions (yy being the year).

GPS Nav = yyN (.24n)
GLONASS Nav = yyG (.24g)
Galileo Nav = yyL (.24L)
BeiDou Nav = yyF (.24F)

My question has been resolved, but I'm leaving this information for anyone who searches for it later on. This was such a HUGE source of frustration for me, and anyone trying to use a Carlson GNSS receiver with Rinex Hemisphere needs to be made aware of this. Not everyone uses GPS constellations, and not everyone uses Opus.

 
Posted : 10/10/2024 4:27 am
(@chris-bouffard)
Posts: 1440
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My thoughts exactly, neither LiDAR or drones should need a "sky plot" as they provide no positional value.

 
Posted : 10/10/2024 6:21 am
(@lurker)
Posts: 925
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He's getting positional value from the GNSS satellites. He wants to know their azimuth above the horizon so that he can exclude the ones that may not provide the best data. He is using the skyplots to obtain that azimuth information.

 
Posted : 10/10/2024 6:35 am
(@jeffca)
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The purpose of a skyplot was to show that my observation file only had GPS Satellites in it. I don't know what's so hard to understand about this. Also, a sky plot is extremely useful in finding out the azimuth of the satellite at the time of collection. When dealing with a kinematic GNSS source, like GPS on a drone, a sky plot is EXTREMELY useful. It's not for processing. It's for analyzing the data.

 
Posted : 10/10/2024 6:35 am
(@bm-nolan)
Posts: 18
Active Member Customer
 

Hi Jeff, What tool are you using in Emlid Studio? I am not super familiar with Emlid Studio but I wanted to take a look at what you were seeing. When I upload my observation 23o file (what I have on hand) I can see that all of the GPS, GLONASS, GALILEO and BeiDou data is there. The funny thing is that the sky plot does not generate for any of my data. I am wondering if there might be an easier fix for you.

I also typically recommend using 2.0.3 for the Rinex convertor, I have had better with that one. I may not get back to you till after Thanksgiving (it's in October in Canada).

 
Posted : 11/10/2024 6:29 am
(@jeffca)
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Topic starter
 

Hi Nolan. I was using Static Processing and Convert to RINEX to view the observation data. You can also use it to convert some other forms of raw data to Rinex. It's a pretty useful tool, but I was merely using it to be sure that all constellations were observed. I also use RTK Library, which is an open source program. Also, very useful.

So I get the same results that you do when converting with 2.0.5. All the GNSS constellation data is in the observation file, but none of the navigation data, hence no sky plot. But like I've said in my previous post I've been able to figure it out. By telling Rinex Hemisphere to create the Navigation Data file for Glonass, BeiDou, and Galileo, which by default is "optional" you'll get that information in your Observation file and you'll be able to view sky plots. The trick is that Rinex Hemisphere does NOT default to the correct file extension. If you don't know what they are, then it simply creates text files with nothing of value in it. So by adding the following extensions when saving the Navigation Data file you'll get all that juicy skyplot data right in your observation file.

GPS Nav = yyN (.24n)
GLONASS Nav = yyG (.24g)
Galileo Nav = yyL (.24L)
BeiDou Nav = yyF (.24F)

So when you click in the box next to a constellation, and select the save as location, be sure to add the appropriate extension. See attached screen shot.

 
Posted : 13/10/2024 9:57 pm
(@bm-nolan)
Posts: 18
Active Member Customer
 

I'll ask around and see if there are any better solutions out there.

 
Posted : 15/10/2024 7:33 am
(@bm-nolan)
Posts: 18
Active Member Customer
 

What other Rinex convertor were you using that gave you the sky plot in the .o file? I was talking to some of the folks at Hemisphere and they say the .o files normally don't contain any navigation data.

 
Posted : 17/10/2024 7:08 am
(@jeffca)
Posts: 6
Active Member Registered
Topic starter
 

I'm only using Hemisphere to convert the .BIN file from my BRX7 to a .24o. I haven't been able to find another way to do it. I find it very odd that they say that .0 files don't normally contain navigation data, because their converter puts GPS data in it by default. It just doesn't add the other constellations by default.

 
Posted : 17/10/2024 9:42 pm
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