Here are the steps for installing GPSD and verifying its performance. They assume you have GPSD available as an installable binary package.
Most of these installation instructions are generic to POSIX.
Instructions for building GPSD from source (including cross-building), and some special notes on installation on *BSD, WSL, OS X, macOS, and the Raspberry Pi are in the file "build.adoc" in the source distribution.
Start by making sure you can get data from your GPS, otherwise the later steps will be very frustrating. In this command:
stty -F /dev/ttyXXX ispeed 4800 && cat </dev/ttyXXX
replace ttyXXX with the filename of the port. This will probably be either /dev/ttyUSB0 or /dev/ttyS0. If you are on a *BSD Unix or MacOS X, replace -F with -f.
When you run this command, you should see text lines beginning with $ come to stdout (possibly after a short initial burst of binary garbage). If you don’t see this, you may have OS-level problems with your serial support, but more likely have the wrong device. Look again.
If you have trouble with the preceding step, check your cabling first. Verify that the device is connected and that its power LED (if it has one) is lit.
If you seem to have some sort of serial-device problem, check that your kernel properly supports the device you are using. For GPSes using an RS-232 port (which is no longer common) you will need serial-port support compiled into your kernel. Various USB-to-serial adapter chips found in GPSes require specific drivers.
Under a stock Linux kernel these will all be loaded on demand when the USB system sees the appropriate vendor/product ID combinations. See build.adoc for instructions relating to custom kernels.
Ensure that device permissions will enable gpsd to read from and write to GPS devices even after it drops root privileges. If you are running Fedora Core, Ubuntu, or stock Debian you can skip this step, as the stock configuration has the right properties.
gpsd requires two things: (1) that GPS devices have group read and write enabled, and (2) all of them have the same group ID as a prototypical device, typically /dev/ttyS0 under Linux or /dev/tty00 under *BSD. It does not actually matter what the owning group is, as gpsd will look this up on startup. Alternatively, (3), you can set a fallback group with the gpsd-group option in case the prototype is not found: this should be the group that has write access to serial devices. On Debian and derivatives including Ubuntu this is "dialout"; on Gentoo/Fedora/openSuse it is "uucp".
Before dropping privileges, gpsd will ensure that it has access to devices given to it on the command line by forcing their group read and write permissions on.
On a Linux with udev, check the files in /etc/udev/permissions.d to ensure that /dev/tty* devices are all created with the same group and with 0660 permissions.
When gpsd drops privileges, its default is to set uid to 'nobody' and group to the owning group of the prototype device (the configure option gpsd-user=foo will cause gpsd to change to 'foo' instead).
If your system has the Linux hotplug facility installed you can skip the permission-setting part; the hotplug scripts will force the permissions for you. You still have to make sure all the tty devices are in the same group.
A minimum build of GPSD can run pretty close to the metal; all it absolutely needs is the C runtime support. The test clients and various additional features have additional prerequisites:
asciidoctor |
to build the documentation and www |
dbus |
gpsd will issue DBUS notifications |
gnuplot |
to plot gpsprof output. |
GTK |
for python-GI |
libtinfo5 |
low-level terminfo library (see below) |
libusb-1.0.x or later |
for older Garmin USB devices |
ncurses |
for cgps and gpsmon clients |
pps-tools |
for PPS time keeping |
PyGObject |
for xps and xgpsspeed clients (see below) |
pyserial |
for ubxtool and zerk in direct-serial mode |
python2.x(x>=6) or 3.y(y>=2) |
required for various clients and utilities |
python-cairo |
for python-GI |
Qt |
libQgpsmm depends on this |
Some ncurses packages contain the terminfo library; some break it out separately as libtinfo5 or libtinfo.
The PyGObject package goes by several names, and is split up into sub packages different ways, depending on the distribution. Sometimes python-gi, python-gobject, python-cairo, etc. The packages also need the underlying system libraries (GTK, GLib, etc.)
The asynchronous python module (gps/aiogps.py) and its example client (example_aiogps.py) require Python 3.6+.
See below for more specific module requirements in the individual distribution instructions.
Before installing gpsd on your system, make sure that all parts of any previous installation have been removed. Do not mix gpsd parts from different sources. The gpsd clients and the server must be of the same version.
Up-to-date gpsd packages are generally available for Linux distributions including Debian and derivatives (including Ubuntu and Mint), Fedora and derivatives (including CentOS), openSUSE, PCLinuxOS, Mageia, Gentoo, and Slackware. In the embedded space, CeroWRT and Yocto carry GPSD. The GPSD package in the FreeBSD ports tree is also reliably up to date. Even if your distribution is not on this list, it is quite likely GPSD has already been packaged for it.
Whatever distribution you are running, the name of the core GPSD package containing the service daemon is almost certainly "gpsd". However, many distributions break up GPSD into separate installable packages for the core daemon and clients; you should search your repository index for anything with gpsd as a prefix.
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You should start gpsd while running as root. Starting as a normal user will cause some loss of functionality. Starting with sudo will cause a different loss of functionality.
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Start gpsd. You’ll need to give it as an argument a path to a serial or USB port with a GPS attached to it. Your test command should look something like this:
gpsd -D 5 -N -n /dev/ttyUSB0
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Once gpsd is running, telnet to port 2947. You should see a greeting line that’s a JSON object describing GPSD’s version. Now plug in your GPS (or AIS receiver, or RTCM2 receiver).
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Type '?WATCH={"enable":true,"json":true};' to start raw and watcher modes. You should see lines beginning with '{' that are JSON objects representing reports from your GPS; these are reports in GPSD protocol.
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Start the xgps or cgps client. Calling it with no arguments should do the right thing. You should see a display panel with position/velocity-time information, and a satellite display. The displays won’t look very interesting until the GPS acquires satellite lock.
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Have patience. If you are cold-starting a new GPS, it may take 15-20 minutes after it gets a good skyview for it to download an ephemeris for each satellites in view, and the current almanac. Only then can it deliver the best quality fixes.
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A FAQ and troubleshooting instructions can be found at the GPSD project site.
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If you installed from a '.deb' package under Debian or a Debian-derived system, you may need to `dpkg-reconfigure -plow gpsd' to enable the hotplug magic ("Start gpsd automatically").
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Check out the list of supported hardware at the Hardware page on the GPSD project’s website. If your GPS isn’t on the list, please send us information to add a new line to the table. Directions are included on that page. We can also use updates of the latest version number known to work with hardware already supported.
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GPSD includes gpsd.php, a PHP script, that you can use to generate a PHP status page for your GPS if you wish. (It may not be in the core package.) It should be manually copied to your HTTP document directory. The first time it’s invoked, it will generate a file called 'gpsd_config.inc' in that directory containing configuration information; edit to taste.
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There are other non-essential scripts that may be useful; these are in the contrib/ directory of the source. They may not be available in the packages available from distributions.
For special instructions related to using GPSD for time service, see the GPSD Time Service HOWTO in the distribution or on the web.
Any USB connected GPS that is known to work with gpsd will work fine on the RasPi. No special instructions apply.
A very popular option is to install the AdaFruit Ultimate GPS HAT. With this GPS you also get a good 1PPS signal. This works as any other GPS with gpsd, but there are two things to note. The GPS takes over the serial console: /dev/ttyAMA0. The PPS signal will be on GPIO Pin #4.
Only three specific changes need to be made to make the HAT work. First in the file /boot/cmdline.txt, remove this part "console=ttyAMA0,115200 kgdboc=ttyAMA0,115200". That frees the serial port from console use so the GPS can use it.
Second you need to tell the boot process to load the pps_gpio module and attach /dev/pps0 to GPIO pin 4. Do that by adding this line to the bottom of /boot/config.txt: dtoverlay=pps-gpio,gpiopin=4
Reboot so those changes take effect.
Run gpsd like this:
~ # gpsd -D 5 -N -n /dev/ttyAMA0 /dev/pps0
If you are on the RasPi with gpsd version 3.17, or above, /dev/pps0 can be autodetected, and used for PPS if available.
gpsd 3.17 and up only:
~ # gpsd -D 5 -N -n /dev/ttyAMA0
You can verify gpsd is using the PPS by running ntpshmmon:
~ # ntpshmmon # Name Seen@ Clock Real L Prec sample NTP0 1461619703.641899335 1461619703.445224418 1461619703.000000000 0 -1 sample NTP2 1461619703.642203397 1461619702.999262204 1461619703.000000000 0 -20 sample NTP0 1461619704.142097363 1461619703.445224418 1461619703.000000000 0 -1 sample NTP2 1461619704.142204134 1461619703.999258157 1461619704.000000000 0 -20
If you do not see NTP2 then you misconfigured the pps_gpio driver.
The serial time is provided to ntpd on NTP0, the PPS time is on NTP2, not on NTP1 like described earlier. So your ntp.conf will need to be adjusted from:
# GPS PPS reference (NTP1) server 127.127.28.1 prefer fudge 127.127.28.1 refid PPS
To:
# GPS PPS reference (NTP2) server 127.127.28.2 prefer fudge 127.127.28.2 refid PPS
Now proceed as for any other operating system to use gpsd.
Be sure to validate that your PPS signal is not offset by the pulse width. That would mean gpsd is using the wrong edge.
Detailed instructions are available from their website: https://learn.adafruit.com/adafruit-ultimate-gps-hat-for-raspberry-pi/
You will need to dig deeper to make the PPS work, here is a good reference: http://www.satsignal.eu/ntp/Raspberry-Pi-NTP.html
Only Windows Subsystem for Linux 1 provides a reasonable means of running gpsd at this time. WSL2 lacks a GUI, USB and serial support making it unsuitable at this time.
WSL 1 is a component of Microsoft Windows that implements an alternate kernel. Linux distributions, notably Alpine, Debian, Kali, OpenSUSE, and Ubuntu may run on top of it.
There are some issues known which affect gpsd.
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/dev/ttyS* nodes have a 1 indexed number, like in MS Windows.
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Windows 10 may attempt to use your GPS itself.
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Older pl2303 (knockoff) serial chipsets are no longer supported \ in Windows 10
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Install a Linux distribution by clicking on the
Microsoft Store\ Icon in the taskbar. -
Click on the search icon (it is a magnifying glass).
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Type in 'Linux' or the name of a supported distribution. (see list)
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Click on the icon of your chosen Linux Distribution
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Click 'Get' then click 'Install' and busy-wait.
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Click on the start menu and scroll to your Linux distribution and \ click it.
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Follow the distribution-specific on-screen instructions to finish \ installing your Linux distribution.
Due to current WSL limitations, it is recommended at this time that you only install the equivalent of the following packages on your distribution.
Python SCons (preferably 3.0+) ncurses-dev (to build/run cgps and gpsmon) asciidoctor (to build the documentation)
Optionally, the following packages might also be installed
pyserial (for direct control of UBlox GPS and GREIS devices) gnuplot (to generate graphs of gpsprof data) libusb-dev (to possibly use crusty old Garmin GPS receivers) git (if building from the development sources)
Follow instructions in the distro-specific section in the file build.adoc.