gpsd is a userland daemon acting as a translator between GPS, GNSS, and AIS receivers and their clients. gpsd listens on port 2947 for clients requesting position/time/velocity information. The receivers are expected to generate position information in a well-known format — as NMEA-0183 sentences, SiRF binary, Rockwell binary, Garmin binary format, or other vendor binary protocols. gpsd takes this information from the GPS and translates it into something uniform and easier to understand for clients. The distribution includes sample clients, application interface libraries, and test/profiling tools.

The website for GPSD where you can find updates, news, and project mailing lists is:

See that website for a list of GPS units known to be compatible.

See the file INSTALL.adoc for installation instructions and some tips on how to troubleshoot your installation. The file build.adoc has instructions for building from source. The packaging/ directory contains resources and suggestions for packagers and distribution integrators.


This software (gpsd) is released under the terms and conditions of the BSD License, a copy of which is included in the file COPYING.


Remco Treffkorn designed and originated the code.

Russ Nelson maintained gpsd for a couple of years.

Carsten Tschach’s gpstrans-0.31b code was the original model for nmea_parse.c.

Bob Lorenzini <> provided testing and feedback.

Brook Milligan <brook@trillium.NMSU.Edu> combined gpsd and gpsclient into one package and autoconfiscated it.

Derrick J. Brashear <> (KB3EGH) added code for the EarthMate DeLorme. He also added "incredibly gross code to output NMEA sentences" (his own words :-) He also did the first cut at DGPS support (see, for the Earthmate.

Curt Mills <> (WE7U) furthered the dgps support, writing the portion for other GPS receivers.

None of these people have been active in 2.X and later versions; gpsd has evolved out of recognition from the 1.X codebase.


Eric S. Raymond drastically rewrote this code in late 2004/early 2005 to clean it up and extend it. The 2.X architecture has become significantly different and far more modularized. His new features included:

  • Documentation (what a concept!)

  • Cleaned up, simplified command-line options.

  • Now understands the GLL (Geographic position - Latitude, Longitude) sentence from NMEA 3.0.

  • Now parses both the NMEA 3.01 and pre-3.01 variants of the VTG sentence correctly.

  • New commands including 'y', 'w', and 'x', since obsolesced by a JSON-based protocol.

  • Massive refactoring — one main loop now calls a self-contained driver object for each type.

  • The GPS-bashing code the daemon uses can now be directly linked as a library, libgpsd(3).

  • C and Python libraries are available to encapsulate the client side of querying gpsd, see libgps(3).

  • Cleaned-up error reporting, we don’t use syslog when running in the foreground but send all error and status messages to the tty instead.

  • Added -n option to do batch monitoring of GPSes.

  • xgpsspeed is working again; xgps has been seriously reworked and improved.

  • RPMs which include installation of gpsd to start up at boot time are available.

  • New gpsprobe program probes the capabilities of GPSes and generates error scattergrams from fixes. (Later this moved to gpsprof.)

  • Autobauding, self-configuration, and hotplugging. gpsd can now get its device from a hotplug script, and figures out itself which baud rate to use and what the GPS’s device type is.

  • Support for SiRF binary mode.

  • Support for RTCM104 and AIVDM.

  • Support for multiple devices.

  • Other test tools — gpsfake, gpscat, gpsmon.

Chris Kuethe <> maintains the OpenBSD port, shipped the 2.34 release, is our SiRF and low-level protocols expert, and does a lot of general hacking and support. He has release authority.

Gary E. Miller <> wrote the driver for Garmin binary protocol and most of the support for PPS handling on serial devices. He has release authority.

Amaury Jacquot <> added DBUS support.

Ville Nuorvala <> wrote the NTRIP support.

We are delighted to acknowledge the assistance of Carl Carter, a field application engineer at SiRF. He assisted us with the correction and tuning of the SiRF binary-protocol driver, shedding a good deal of light on murky aspects of the chip’s behavior.

We are also delighted to acknowledge the assistance of Timo Ylhainen, VP of Software Operations at Fastrax. He clarified some points about the iTalk protocol, helping to further development of iTalk support.


The main feature of the 3.x versions is a stabilized and finalized version of the JSON command/response protocol. This was designed and mainly implemented by ESR. Gary E. Miller <> wrote the subframe support, gpsplot, gpscsv, and gpssubframe.


Project web site:


This file is Copyright 2013 by the GPSD project
SPDX-License-Identifier: BSD-2-clause