Building RTKLIB code in Linux

In my last post I described building the RTKLIB code in Windows. In this post I will describe building the code in Linux. Unlike for Windows, pre-built executables are not available for either the demo5 or the official 2.4.3 versions of RTKLIB, so building your own code is more of a necessity on this platform.

I have built Linux versions of RTKLIB on both a PC running Ubuntu and on a Raspberry Pi and will describe these experiences. My description may be somewhat specific to these platforms but I believe the process should be very similar on any other Linux system.

The original RTKLIB did not support Linux for the GUI apps but a few years ago Jens Reimann created a version using Qt that supports Linux as well. Those changes are now in both the demo5 and the 2.4.3 versions of RTKLIB and I will describe building these on the Ubuntu platform below.

Building the RTKLIB CUIs on a Raspberry Pi

Let’s focus on just the CUI (Character User Interface) RTKLIB apps for the Pi since the GUIs apps are probably not a good choice for this hardware. We’ll start with just compiling a single app. I will assume that you are connected to a headless Pi through an SSH window and that the Pi is already connected to the internet.

In this case, the following set of commands should be all you need to build RTKRCV, the real-time app for generating RTK or PPP solutions.

git clone https://github.com/rtklibexplorer/RTKLIB.git
cd RTKLIB/app/rtkrcv/gcc
make

The first line pulls the source code from the Github repository, the second line gets you into the Linux build folder for RTKRCV, and the third line builds the code. The default compiler warning threshold is pickier than for Windows, so you will see some warning messages but you can ignore these. You can build the STR2STR, CONVBIN, RNX2RTKP, and POS2KML in the same way by changing the app name in the second line.

Most likely, the only two apps you would be using on the Pi would be the real-time apps, either RTKRCV or STR2STR. However if you would like to build all five CUI apps with a single command you can run “make” from the /RTKLIB/app folder.

If you do get any build errors it is most likely going to be because you are missing one of the build tools. However I have found that if you are using one of the standard releases of Debian Linux for the Pi, this should not be a problem.

Building the RTKLIB CUIs and GUIs on an Ubuntu PC

In this case I am building the code with Ubuntu 20.04 on a Linux partition on a Windows PC, but I don’t think other platforms should be very different.

Before building either the CUIs or the GUIs you will most likely need to update your build tools. I used the following commands to resolve various build errors I ran into when I started with a fresh installation of Ubuntu 20.04

sudo apt-get update
sudo apt install build-essential
sudo apt-get install libpng-dev
sudo apt-get install qt5-default libqt5serialport5-dev

The first line may not be necessary, it just updates the package lists for the following commands. The second line installs the most common build tools, the third line installs the “png” library, and the last line installs the Qt tools.

Once the tools are installed, you can build the CUI apps using the same process I described above for the Pi.

The GUI apps require the core code be built first before the individual apps, so it is easiest to build all the apps at once rather than one at a time. You can do this with the following commands.

git clone https://github.com/rtklibexplorer/RTKLIB.git
cd RTKLIB/app
qmake
cd ..
qmake
make

The first line pulls the source code from Github and is not necessary if you have already done this to build the CUIs. The second line gets you to the app folder in the RTKLIB code where the third line creates a makefile for the Qt apps. The fourth line gets you back to the top level folder where the fifth line creates the makefile for the full build process. The last line builds all the CUI and GUI apps.

It will take a fairly long time to build everything the first time but if you make any changes to the code, these will usually compile much faster. You will also see many warning messages which you can ignore. To rebuild all the apps, you only need to run the last line. Alternatively, after you have run the full process once, you can run “make” from any of the app folders to rebuild just that app.

Note that this process will overwrite the makefile in the RTKLIB/app folder that we used to build just the CUIs in the earlier step, so if you use this process, you won’t be able to build just the CUI’s as a group anymore.

I have tested these Qt GUI apps only briefly but they seem to be functional. However, the GUI interface does not include some of the config parameters added to the demo5 code that are not in the official 2.4.3 code. I believe as a partial workaround, you can most likely update the config file and load it to the GUI to configure these parameters but I have not actually tested this. The core code is shared between all the apps, so as long as the interface is working, the code behavior should not be different regardless of which app or which version of it you are running.

Please add a comment below if you have any corrections or suggested improvements to the process I have described.

[Update 6/23/21: Jens Reimann has recently merged the b34 changes into his fork of RTKLIB which does support the Qt GUIs. I have pulled his set of Qt build files into the demo5 code. The demo5 Qt GUIs now build and are reasonably functional but will still require some updating to include the config parameters unique to the demo5 code. RTKCONV and RTKPOST appear to be working fine but I notice that RTKPLOT does not seem to be fully functional in either his version or the demo5 version. My bandwidth to support this platform is fairly limited so I would be happy to accept pull requests to the demo5 code for any Qt related fixes and improvements.

The build instructions have changed slightly to work with his code

cd app/qtapp
qmake
make
./install_qtapp ]

[Update 1/19/21: Version b34 of the official 2.4.3 RTKLIB code has just been released. It is a major rewrite of the user interface and the changes have not been incorporated into the Qt files. The Qt files are still in the repository but are planned to be dropped in the next release since they are no longer functional. I will be following the lead of the 2.4.3 code in the demo5 version, so unless this changes, the Qt code will not have any future in either codebase. Other readers have reported success using WINE to run the Windows executables, so for those who don’t need to build custom versions of the code, this might be a better choice.]

Building RTKLIB code in Windows

For most users running RTKLIB in Windows there is probably no need to build their own executables, it’s simpler to just download the pre-built demo5 executables from here or the 2.4.3 executables from here.

However, there are a few reasons why you might choose to download the source code and build your own executables instead. First of all, the pre-built executables are built with a large number of options enabled, but not all options. This means they will work for most user configurations but there are some less common configurations they won’t be able to handle. In addition, because they have so many options enabled, they will run slower and use more memory than executables built with only the minimum required number of options enabled.

Also, the latest available executables will not include the most recent updates to the code, you will need to build your own version to get these. And of course, anyone who wants to make any changes to the code will have to build their own executables.

OK, so let’s say you’ve decided to build your own versions. How do you go about doing it? It’s not a complicated process, most reasonably computer-savvy users would be able to figure it out on their own, but I’ll try to provide a few tips below to make it a little quicker and less painful.

The first step is to download the source code from the Github repository. I will assume you are using the demo5 code which is available here, but the same process will work with the official 2.4.2 or 2.4.3 code as well. Click on the “Code” box on the Github repository page to download the code. If you are familiar with Github you may choose to clone the repository or open with Github desktop but for most users it is probably simplest to just choose the “Download ZIP” option and then unzip the code to your desired location on your local drive.

The next step is to choose your compiler. You can use either Microsoft Visual Studio or Embarcadero C++ Builder. Both have community editions which can be downloaded and used for free for non-commercial use. However, Visual Studio will only build the RTKLIB command line apps, not the GUIs, so unless you already have Visual Studio on your computer and only need the command line apps, I would suggest using the Embarcadero compiler.

Now go back to the RTKLIB code folder you just downloaded and unzipped. Most of the common source code is in the “/src” folder but each RTKLIB app has its own sub-folder inside the “/app” folder. Let’s use RNX2RTKP, the RTKLIB command line post-processing solution app, as an initial example. In the “/app/rnx2rtkp” folder you will see a number of different sub-folders for different build methods.

Build a single app with the Embarcadero C++ Builder

Let’s assume for now you are using the Embarcadero compiler and want to build the 64-bit version of the code. You will want to open the “/bcc_win64” folder and within that folder you will see an Embarcadero project file called “_rnx2rtkp_win64.cbproj”. Double-click on this file to open the 64-bit version of the project in the Embarcadero compiler. If your hardware only supports 32-bit executables, you can select the “/bcc/_rnx2rtkp.cbproj” project file instead. When the compiler opens, it should look something like this:

From the “Project” menu, click on “Make _rnx2rtkp_win64” to compile the code. When done, the result should look like the image below. Make sure it says “Linking: Done” and “Errors: 0”

And that’s it. The result, “_rnx2rtkp_win64.exe”, will be in the “\app\rnx2rtkp\bcc_win64\Release_Build” folder.

The only differences for the GUI apps are that the project files are directly in the app folders rather than in sub-folders and in some cases there are separate app folders for the 32 bit and 64 bit versions. For example, for RTKNAVI, you will find a “app/rtknavi/rtknavi.cbproj” project file and a “app/rtknavi_win64/rtknavi_win64.cbproj” project file.

Build a single command line app with Microsoft Visual Studio.

The instructions for Microsoft Visual Studio are very similar, however you will only be able to build the CONVBIN and RNX2RTKP apps since Visual Studio does not support the GUI apps.

After installing Visual Studio, click on the “msc.sln” project file in the “\app\rnx2rtkp” folder to open the project.

Choose “Build Solution” from the “Build” menu to compile the code. The resulting executable will be in the “app\rnx2rtkp\msc\Release” folder.

The project will default to a 32-bit version but you can add a 64-bit version using the Configuration Manager, just be sure to to check the Build box in the new configuration as shown below.

Building and installing the entire RTKLIB library with the Embarcadero C++ Builder

If you are using the Embarcadero compiler and would like to build all the RTKLIB apps at once instead of one at a time, you can use the “rtklib_consapp.groupproj” and “rtklib_winapp.groupproj” project files in the “/app” folder to build the console apps and GUI apps respectively. From the “Project” menu, select “Make All Projects” for each of these group projects. You will see errors when the GUI project attempts to build the RTKVIDEO and RTKVPLAYER apps but you can ignore these, assuming you don’t plan to use these apps.

After completing the builds, run the batch files “app/install_consapp.bat” and “app/install_winapp.bat” to copy all the executables from the “Release” folders to the single “../RTKLIB_bin/bin” folder. You will need to create the destination folder first to avoid errors when it copies the files.

Modifying the build options with the Embarcadero C++ builder

So far, I’ve assumed you want to build with the default build options but sometimes you will want to change these. I will describe the procedure for the Embarcadero compiler, but the procedure is very similar for Visual Studio.

Open the project in Embarcadero for an individual app and then select “Options” from the Project Menu. Select “C++ Compiler->Directories and Conditionals” from the choices in the left column and then set the “Target” box near the top center to “All configurations – All platforms” as shown in the image below. Click on the three dots at the end of the “Conditional defines” list to open up a list of the current defines.

You can now add or remove any of the “Conditional defines” from the list. The definitions of the default defines are as follows:

WIN32: Use the WIN API – use for 32 bit or 64 bit apps
ENAGLO: Enable GLONASS
ENAGAL: Enable Galileo
ENAQZS: Enable QZSS
ENACMP: Enable Beidou
ENAIRN: Enable IRNSS
NFREQ=3: Max # of frequencies, 3=L1+L2+L5, must be >=2 for u-blox
NEXOBS=3: # of extra observations, used to store multiple codes per freq

Other optional defines are:

ENALEO: Enable LEO
ENALEX: Enable QZSS LEX extension
WIN_DLL: Generate Library as Windows DLL

I have not tested any of these optional defines, so no guarantee if any of them work.

Well, I think that’s about it. I’ve probably forgotten something, but this should be enough to get you started.

In my next post, I will cover building the code in Linux.