GPS Speedreader

GPS Speedreader Downloads


GPS Speedreader is a program to analyze GPS tracks from modern GPS units. The program was specifically developed for the GPS Team Challenge, in close collaboration with GPSTC advisors.

GPS Speedreader is free to use, and supplied without any warranties.

The current GPS Speedreader version is 2.2.2 released October 8, 2023.


The links below are ZIP files that contain the applications for MacOS and Windows, and an executable jar file for Linux. To run GPS Speedreader, Java must be installed on your computer (version 8 or newer). If Java is not installed on your computer, you can download it for free at


Download the ZIP archive from and unpack the ZIP archive. Requires MacOS 10.9 or newer.

After downloading and unzipping, move the application to your application folder (or a folder of your choice). When you start GPS Speedreader the first time, you will probably see a warning dialog “GPS Speedreader can’t be opened because it is from an unidentified developer”. To open the application anyway, you can right-click on the GPS Speedreader icon, which will show a slightly different dialog that gives you an option to open the application.


Download the ZIP archive from and unpack the ZIP archive.

After downloading and unzipping, move the application to a folder of your choice. When downloading or running GPS Speedreader the first time, you may see one or more warning dialogs from Windows and/or your antivirus software that you have to click through.


Download the ZIP archive from and unpack the ZIP archive.

After downloading and unzipping, move the GPSSpeedreader.jar file to a folder of your choice. If Java is correctly installed on your system, you should be able to start GPS Speedreader by double-clicking on the GPSSpeedreader.jar file.

Recent Changes

Version 2.2.2

  • Accuracy improvements in turn analysis
  • Several improvements for 1 Hz data
  • Fixed a bug reading GPX files with time stamps containing second fractions

Version 2.2.1

  • New turn analysis window with option to analyze jibes, tacks, or both
  • New “Sorted Speeds” window
  • Fixed a problem with viewing results in browser for file names with unusual (non-ascii) characters

Version 2.1.4

  • Fixed a bug that sometimes caused the date to be off by one day when posting to GPSTC
  • Remove filtered trackpoints when erasing filtered speeds
  • Require identical data rates and similar file sizes to build “intelligent average” tracks

Version 2.1.2

  • Fixed bugs that caused time for data from .gpy files to be shown incorrectly, and wrong times saved when exporting to .gpy files
  • Added a workaround for .gpy files which contain records with invalid time stamps

Version 2.1.1

  • Support for reading files in .gpx format and speed calculations when “doppler” speeds are missing
  • Support for reading and exporting files in the new “compact GNSS” (.gpy) format
  • The default format when exporting tracks is now .gpy. To export in .sbp format, change the file extension to .sbp when exporting.
  • When comparing two files using the “Compare Files” function and the two files have the same number of points, and either different extensions or nearly identical file names, a point-by-point comparison of all data items is done (intended for testing reading and writing in new file formats like .gpy)

Version 2.0.1

  • Support for “intelligent averaging” (intented for DIY loggers mounted to both sides of the boom)
  • Open dialogs now allow.the selection of multiple files
  • Separate and lower accuracy filter thresholds for files from u-blox GPS units (Motion, DIY loggers)
  • Read FIT files from Garmin, Coros, and other watches
  • Alphas can now partially (for up to half of the points) overlap with faster alphas
  • When comparing files, very small differences are not highlighted in the results table any more (up to 0.04 knots for speeds, and 0.2% differences in distance)

Version 1.4.3

  • Fixed an issue where exported SBP files sometimes contained wrong dates
  • Better handling of very large files on Windows with some older (32-bit) Java versions

Version 1.4.2

  • Fixed a problem reading .sbp files with non-Locosys headers
  • Additional speed improvements for alpha calculation if files have large stationary periods

Version 1.4.1

  • New “Angle to wind” column
  • Polar plot improvements
  • Added ability to compare files from different dates

Version 1.4.0

  • Added “Export” to save tracks to files in SBP format; bug fixes

Version 1.3.8

  • Support zooming in the tracks and speed panels using keyboard shortcuts; bug fixes

Version 1.3.7

  • Added “Forget map..” to “View” menu to remove outdated background maps

Version 1.3.6

  • Support for background maps
  • Distance measurements in the tracks panel by alt-dragging (Linux users may need to press alt+shift while dragging)
  • Alphas with 60 and 70 m gate widths are now also shown in the results table
  • Sliders for zooming in the tracks and speed panels
  • New options to highlight the selected regions by color, and to set the line width for the selection
  • Faster calculation of alphas for files with long stationary periods
  • New latitude and longitude column options for the trackpoint table

Version 1.3.4

  • Better handling of Motion .oao files with corrupt records
  • Support .sbp files that contain older sessions after newer sessions

Version 1.3.3

  • Changed posting to GPSTC to use the same window and https to get around problems that some browsers showed recently

Version 1.3.3

  • Changed posting to GPSTC to use the same window and https to get around problems that some browsers showed recently

Version 1.3.2

  • Fixed a bug reading UBX files from 2020

Version 1.3.1

  • Fixed a problem where export to Google Earth produced incorrect files on computers using languages other than English
  • New “Combine files” function

Version 1.3.0

  • If files contain multiple sessions, users can choose which session to analyze
  • New “Remove filtered points” and “Remove selection” menu items
  • Turn analysis (experimental) shows turns with the highest minimum speed in the speed results table. The second column shows the “score” - the percent of the maximum entry speed (looking back 50 meters from the turn center) kept.

Version 1.2.9

  • Handle time rollbacks (leap second adjustments) in files correctly
  • Fixed a minor bug in results table (number of results not changed correctly when filters change)

Version 1.2.8

  • Support .sbn files (from GT-31)
  • Option to define highlight colors when exporting to Google Earth
  • Bug fixes

Version 1.2.7

  • Export for Google Earth
  • Show speed as tooltips in speed panels

Version 1.2.5

  • Better highlighting of selection regions in tracks (thicker lines, crosshair is at first selected point)
  • Popup menu in tracks panel to allow easy switching between drawing full and partial tracks

Version 1.2.4

First public release.