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#1 2021-01-17 00:37:11

Alexey Vazhnov
Member
From: Wrocław, Poland
Registered: 2009-09-01
Posts: 134
Website

Wrocław: high precision GNSS tracks

I'm creating GPX tracks near Wrocław, because some of villages have no any track available to check satellite imagery offset.

I found that Wrocław has a station LEICA GR50 from ASG by EUPOS: http://www.asgeupos.pl/index.php?wpg_ty … sub=ref_st

How can I use the signal of this station to create high quality GPX tracks?

Should I use any of RTKLIB-compatible GPS devices?

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#2 2021-01-17 14:44:37

Mateusz Konieczny
Member
Registered: 2013-09-22
Posts: 2,130

Re: Wrocław: high precision GNSS tracks

Note that in Poland geoportal.gov.pl aerial imagery is so good that it can be used to align other aerial imagery.

Alexey Vazhnov wrote:

How can I use the signal of this station to create high quality GPX tracks?

Should I use any of RTKLIB-compatible GPS devices?

Sadly I have no idea at all here sad

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#3 2021-01-17 15:09:27

RicoElectrico
Moderator
From: Trójmiasto
Registered: 2012-07-01
Posts: 1,700

Re: Wrocław: high precision GNSS tracks

ASG-EUPOS is now a paid service. It was free only in the beginning.

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#4 2021-01-18 23:53:14

Alexey Vazhnov
Member
From: Wrocław, Poland
Registered: 2009-09-01
Posts: 134
Website

Re: Wrocław: high precision GNSS tracks

Sad. I need accurate GNSS tracks not for checking satellite imagery offset only, but also for example to create good quality image sequences for Mapillary.

So, as an alternatives:

  1. Buy device with multiband GNSS (L1 + L5 GPS)

  2. Buy some RTK kit (SparkFun / u-blox ?), create own station and share diff into internet.

  3. Buy temporary access from, for example, https://www.tpinet.pl/kup-dostep

First step looks good. Anyway I need more accurate GNSS to work with RTK.

Any other idea?

Last edited by Alexey Vazhnov (2021-01-19 00:05:52)

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#5 2021-03-07 15:06:37

Alexey Vazhnov
Member
From: Wrocław, Poland
Registered: 2009-09-01
Posts: 134
Website

Re: Wrocław: high precision GNSS tracks

I've ordered from digikey.pl:

  • SparkFun GPS-RTK-SMA ZED-F9P BREAKOUT — board with u-blox ZED-F9P

  • U-Blox ANN-MB-00-00 — active antenna, IP67

But there was no metal ground plane which is highly recommended by u-blox. I hope, any piece of metal will be fine for this.

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#6 2021-03-26 10:52:19

Alexey Vazhnov
Member
From: Wrocław, Poland
Registered: 2009-09-01
Posts: 134
Website

Re: Wrocław: high precision GNSS tracks

My precious arrived!

I had to pay import tax 290 PLN in addition to shop price 1170 PLN…

4990d9d7e8938e32.jpeg

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#7 2021-03-26 11:54:45

RicoElectrico
Moderator
From: Trójmiasto
Registered: 2012-07-01
Posts: 1,700

Re: Wrocław: high precision GNSS tracks

That's quite a lot of money.
Do you know of any cheap standalone L1+L2 receivers? In open sky conditions they are pretty good, as tested by some Xiaomi phone users on our FB group.
But I don't want to buy a phone just to record tracks. big_smile

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#8 2021-03-26 12:10:15

Alexey Vazhnov
Member
From: Wrocław, Poland
Registered: 2009-09-01
Posts: 134
Website

Re: Wrocław: high precision GNSS tracks

RicoElectrico wrote:

Do you know of any cheap standalone L1+L2 receivers?

I don't know.

I saw some cheap "multiband" modules on aliexpress, but I don't believe they are really multiband. I think it is better to take some old used u-blox NEO-M8* / NEO-M9* modules than to buy fake "multiband" module with unknown precision. As I understand, it is better to use L1 receiver with correction than multiband receiver without correction data.

You can take a look at https://rtklibexplorer.wordpress.com , he is "exploring precision GPS/GNSS with RTKLIB open source software and low-cost u-blox GNSS receivers".

Also you can take my module when you need it. I'm in Wrocław smile

Last edited by Alexey Vazhnov (2021-03-26 12:12:33)

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#9 2021-03-26 12:22:58

SK53
Member
Registered: 2009-01-11
Posts: 598

Re: Wrocław: high precision GNSS tracks

People I know on OSM using RTK include Jean-Guilhem Caiton (jgc) with ublox modules in France & in the UK both Russss and Firefishy have recently acquired them. There's also a thread in this forum in Russian on RTK. It's possible that sharing experience & advice would be useful. I felt that perhaps this was something a national association could invest in: however, in the UK we now have accurate open data on cadastral parcels which fulfills the purpose of high-quality image alignment.

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#10 2021-03-31 13:17:40

MikeN
Member
Registered: 2009-09-03
Posts: 326

Re: Wrocław: high precision GNSS tracks

I used a US 1 gallon paint can lid as the ground plane.  It is very close to the recommended size.

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#11 2021-04-04 09:17:10

Alexey Vazhnov
Member
From: Wrocław, Poland
Registered: 2009-09-01
Posts: 134
Website

Re: Wrocław: high precision GNSS tracks

MikeN wrote:

I used a US 1 gallon paint can lid as the ground plane.  It is very close to the recommended size.

I'm using something similar, thank you!

I solved problem with GPSBabel: https://help.openstreetmap.org/question … -by-radius
So now I have a script to convert all NMEA files into one GPX and filter them to remove some noise.

I'm satisfied with a quality of tracks even without correction. Maybe I will not use a correction, because wrong correction can create a align for all tracks (am I right in this?).

My current setup:

  • Receiver SparkFun GPS-RTK-SMA ZED-F9P

  • IP67 active antenna: U-Blox ANN-MB-00-00, with 5 meters cable…

  • Single board computer: i.MX53 Quick Start board (1 GB RAM), it uses 5V x 0.3-0.5A when running

  • Noname powerbank with 3x18650 and controller TPOWER TP4366

  • Rainproof bag https://www.sportarsenal.cz/brasny/art--310/

Ta-da! Here are the tracks: https://www.openstreetmap.org/user/Alex … %20zed-f9p

Started a wiki-page: https://wiki.openstreetmap.org/wiki/Use … NSS_traces

TODO:

  • Better metal ground plane

  • Current setup spends whole bag, I need to make it more compact

  • Better power supply: my SBC can eat more than 1A when initializing, and my powerbank switches off sometimes on start

  • Replace SBC with a simple logger

  • Add Bluetooth to have connection with Android smartphone

Last edited by Alexey Vazhnov (2021-04-04 16:35:38)

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