This is a GPS-based position tracker and logger. It uses the same GPS receiver and similar radio to our flight computers, but does not include pyro circuits. This allows the board to be small and light, so that it will fit well anywhere you need a good GPS tracker.

For the latest TeleGPS firmware and related ground station software, please visit the AltOS page on this site.

These are photos of production version 1.0:


The manual for TeleGPS is available in html and pdf formats.


The TeleGPS application runs on Linux, Mac OS X and Windows. It's written in Java and offers the same functionality and interface on all three platforms. It uses the FTDI USB Serial drivers to communicate with the hardware. If you're running Mac OS X or Windows, a compatible version of those drivers is included with the software. You can also install a different from from the FTDI Driver page.

TeleGPS is part of the larger AltOS suite of software, which also includes a dedicated MicroPeak application.

Available Versions

TeleGPS version 1.6.8

Release Notes for Version 1.6.8

Release Notes for Version 1.6.8

Version 1.6.8 fixes a TeleMega and TeleMetrum v2.0 bug where the device could stop logging data and transmitting telemetry in flight. All TeleMega v1.0, v2.0 and TeleMetrum v2.0 users should update their flight firmware.

1. AltOS

AltOS fixes:

  • Fix STM32L DMA driver to work around STM32L SoC DMA priority issue t lock-up in the logging or radio code, either of which could stop data logging and telemetry.
  • Avoid having TeleBT battery status values smash telemetry packet data by holding a lock during both operations.
  • Don’t start reporting flight 0 when the log fills in flight.

AltOS changes:

  • Flash LEDS on all products briefly during power up so that they can be tested during production.

2. AltosUI, TeleGPS and AltosDroid Applications

AltosUI fixes:

  • Re-enable go/no-go entries after they’ve been disabled due to lack of data. If telemetry information is delayed when the Ui starts up, sometimes important fields would get disabled to never re-appear.
  • Deal with ground station failure better during Configure Ground Station operation by cleaning up pending operations.

TeleGPS version 1.6.5

Release Notes for Version 1.6.5

Release Notes for Version 1.6.5

Version 1.6.5 fixes a TeleMega and TeleMetrum v2.0 bug where the device would often stop logging data and transmitting telemetry in flight. All TeleMega v1.0, v2.0 and TeleMetrum v2.0 users should update their flight firmware.

1. AltOS

AltOS fixes:

  • Fix STM32L SPI driver to prevent lock-up in the logging or radio code, either of which could stop data logging and telemetry. Found and characterized by Chuck Haskin, who also tested the new firmware before release.

2. AltosUI, TeleGPS and AltosDroid Applications

AltosUI fixes:

  • Deliver firmward for TeleMega v2.0 and TeleBT v3.0 with Windows package.

TeleGPS version 1.6.4

Release Notes for Version 1.6.4

Release Notes for Version 1.6.4

Version 1.6.4 fixes a bluetooth communication problem with TeleBT v1.0 devices, along with some altosui and altosdroid minor nits. It also now ships firmware for some newer devices.

1. AltOS

AltOS fixes:

  • Fix hardware flow control on TeleBT v1.0. Hardware RTS/CTS doesn’t seem to work, switch from using the hardware to driving these pins with software.
  • Fix ARM USB drivers to deal with OS restarts. Needed to reset all USB-related state when the USB bus is reset. These fixes affect all STM32L, STM32F0 and LPC11U14 based devices.

2. AltosUI, TeleGPS and AltosDroid Applications

AltosUI, TeleGPS and AltosDroid New Features:

  • Automatically switch from meters or feet to kilometers or miles for distance units.
  • Add Monitor Idle mode to TeleGPS application.

AltosUI, TeleGPS and AltosDroid Fixes:

  • Abort map preloading when the preload map dialog is closed.
  • In AltosDroid, Don’t reconnect to last device if the user had disconnected it the last time the application was active.

3. Documentation

  • Mention TeleMega v2.0 in hardware specs table.
  • Document TeleGPS RF output in telegps manual.

TeleGPS version 1.6.3

Release Notes for Version 1.6.3

Release Notes for Version 1.6.3

Version 1.6.3 adds idle mode to AltosDroid and has bug fixes for our host software on desktops, laptops an android devices along with BlueTooth support for Windows.

1. AltOS

AltOS fixes:

  • Fix hardware flow control on TeleBT v3.0. RTS/CTS is wired backwards on this board, switch from using the hardware to driving these pins with software.

2. AltosUI and TeleGPS Applications

AltosUI and TeleGPS New Features:

  • Add BlueTooth support for Windows operating system. This supports connections to TeleBT over BlueTooth rather than just USB.

AltosUI and TeleGPS Fixes:

  • Change Java detection and install on Windows. Detection is now done by looking for the javaw.exe program, and installation by opening a browser on the web site.
  • Delay polling while the Fire Igniters is visible to allow for TeleMega to report back complete status over the radio.
  • Disallow changing RF calibration numbers in the configuration UI. There’s no good reason to change this from the field, and recovering is really hard if you haven’t written down the right number.
  • Fix USB device discovery on Mac OS X El Capitan. This makes the connected Altus Metrum USB devices appear again.
  • Fix acceleration data presented in MonitorIdle mode for TeleMetrum v2.0 flight computers.

3. AltosDroid

AltosDroid new features:

  • Monitor Idle mode. Check state of flight computer while in idle mode over the radio link
  • Fire Igniters. Remotely fire ignires for recovery system ground tests.
  • Remote reboot. Cause the flight computer to reboot over the radio link. This provides a method for switching the flight computer from idle to flight mode without needing to reach the power switch.
  • Configurable frequency menu. Change the set of available frequencies and provide more descriptive names.

AltosDroid bug fixes:

  • Don’t set target location if GPS hasn’t locked yet.
  • Fix saving target states so they can be reloaded when the application restarts. When the application is shut down and restarted, all previous target state information will be restored (including GPS position if available).
  • Fix crash on some Android devices for offline maps when changing the map scale or location.
  • Don’t require USB OTG support. This kept the latest AltosDroid from being offered on devices without USB device support, although it can work without that just fine using BlueTooth.
  • Don’t require bluetooth to be enabled. This allows the application to operate with USB devices or just show old data without turning on the bluetooth radio.
  • Recover old tracker positions when restarting application. This finally allows you to safely stop and restart the application without losing the last known location of any tracker.

4. Documentation

  • Document TeleMega and EasyMega additional pyro channel continuity audio alert pattern.

TeleGPS version 1.6.2

Release Notes for Version 1.6.2

Release Notes for Version 1.6.2

Bdale Garbee

Keith Packard

This document is released under the terms of the Creative Commons ShareAlike 3.0 license.

Version 1.6.2 includes support for our updated TeleMega v2.0 product and bug fixes in in the flight software for all our boards and ground station interfaces.

1. AltOS

AltOS New Features:

  • Add support for TeleMega v2.0 boards.
  • Add PWM servo driver. There’s no higher level code using this yet, but the driver allows testing of the TeleMega v2.0 servo output connector.

AltOS Fixes:

  • Slow down telemetry packets to allow receiver to keep up.

2. AltosUI and TeleGPS Applications

AltosUI and TeleGPS Fixes:

  • Fix post-flight orientation computation when processing TeleMega and EasyMega eeprom data files.
  • Capture complete eeprom data even when there are invalid entries in the data. This keeps reading eeprom contents and writing the associated .eeprom file when an error is detected.

3. Documentation

We spent a bunch of time trying to improve our documentation

  • HTML versions now have a table of contents on the left side.
  • EasyMini now has its own shorter manual.
  • Provide links between sections in each document.
  • Lots of minor rewriting and restructuring to avoid duplication of information

TeleGPS version 1.6.1

TeleGPS version 1.6

Version 1.6 includes support for our updated TeleDongle v3.0 product and bug fixes in in the flight software for all our boards and ground station interfaces.

AltOS New Features

  • Add support for TeleDongle v3.0 boards.

AltOS Fixes

  • Don't beep out the continuity twice by accident in idle mode. If the battery voltage report takes longer than the initialiation sequence, the igniter continuity would get reported twice.

  • Record all 32 bits of gyro calibration data in TeleMega and EasyMega log files. This fixes computation of the gyro rates in AltosUI.

  • Change TeleDongle LED usage. Green LED flashes when valid packet is received. Red LED flashes when invalid packet is received.

  • Replace LPC11U14 SPI driver with non-interrupt version. The interrupt code would occasionally wedge on long transfers if interrupts were blocked for too long. This affects all released TeleGPS products; if you have a TeleGPS device, you'll want to reflash the firmware.

AltosUI and TeleGPS New Features

  • Compute tilt angle from TeleMega and EasyMega log files. This duplicates the quaternion-based angle tracking code from the flight firmware inside the ground station software so that post-flight analysis can include evaluation of the tilt angle.

  • Shows the tool button window when starting with a data file specified. This means that opening a data file from the file manager will now bring up the main window to let you operate the whole application.

AltosUI Fixes

  • Show the 'Connecting' dialog when using Monitor Idle. Lets you cancel the Monitor Idle startup when connecting over the radio link.

  • Make 'Monitor Idle' work for TeleGPS devices when connected over USB. It's nice for testing without needing to broadcast over the radio.

  • Use different Windows API to discover USB devices. This works better on my Windows 7 box, and will be used if the older API fails to provide the necessary information.

  • Look in more places in the registry to try and identify the installed Java version on Windows. If you install the default 32-bit version of Windows on a 64-bit OS, the Java registry information is hiding \SOFTWARE\Wow6432Node for some reason.

  • Fix file association on Windows by searching for the javaw.exe program instead of assuming it is in %SYSTEMROOT%. This makes double-clicking on Altus Metrum data files in the file manager work correctly.

  • When replaying a file, put 'done' in the Age field when we reach the end of the file, instead of continuing to count forever.

  • In the Scan Channels code, wait for five seconds if we see any packet. This is needed because AltOS now sends the callsign, serial number and flight number only once every five seconds these days.

  • In the Scan Channels code, reset pending flight state information each time we change channels. This avoids having flight computers appear on multiple frequencies by accident.

TeleGPS version 1.5

Version 1.5 is a major release. It includes support for our new EasyMega product, new features and bug fixes in in the flight software for all our boards and the AltosUI ground station

AltOS New Features

  • Add support for EasyMega boards.

  • Make the APRS SSID be configurable. This lets you track different rockets on the same receiver without getting things mixed up.

  • Report extra pyro channel continuity state on EasyMega and TeleMega via the beeper. This lets you easily verify flight readiness on these boards after powering up the electronics on the rail.

  • Add lower telemetry data rates (2400 and 9600 bps) to increase telemetry radio range. This reduces the amount of data received as well as increasing battery consumption in the transmitter.

  • Change TeleGPS to have only a single log, and append new data to it rather than using seperate per-flight logs. This avoids accidentally filling up log storage by turning TeleGPS on/off several times.

AltOS Fixes

  • Increase the maximum range for altitude values from +/-32767m to +/-2147483647m, allowing the flight computers to function correctly above the 32km level.

  • Continuously test pyro firing conditions during delay stage, inhibiting the pyro channel if the test fails. This prevents firing pyro charges where the conditions were good before the delay, but become bad before the delay expires.

  • Allow negative numbers in pyro configuration values. This lets you specify things like descending speed or deceleration.

AltosUI and TeleGPS New Features

  • Support telemetry baud rate selection. Adds menus to the flight monitoring and configuration for baud rate selection.

  • Support APRS SSID configuration.

  • Integrate with file managers. This provides icons for all of our file types and associates our application with the files so that using a file manager to open a AltOS data file results in launching our application.

AltosUI Fixes

  • Make the 'Graph' button on the landed tab work again.

  • Make tests for Java on Windows a bit smarter, and also provide the user with the option to skip installing Java for cases where we just can't figure out what version is installed.

TeleGPS version 1.4.1

Version 1.4.1 is a minor release. It fixes install issues on Windows and provides the missing TeleMetrum V2.0 firmware. There aren't any changes to the firmware or host applications at all. All Windows users will want to upgrade to get the signed driver, but Mac and Linux users who do not need the TeleMetrum V2.0 firmware image will not need to upgrade.

Windows Install Fixes

  • Provide signed Windows driver files. This should avoid any need to disable driver signature checking on Windows 7 or 8.

  • Fix Java version detection and download. Previously, the installer would only look for Java 6 or 7 and insist on downloading its own Java bits if there was something else installed. Furthermore, the 64-bit Java link provided didn't work for anyone other than Keith, making it impossible to install AltOS on any machine with Java SE 8 installed.

Other Fixes

  • Include 1.4 firmware for TeleMetrum V2.0. None of the installers shipped this file. Now it's included in the AltOS packages for Linux, Mac and Windows.

  • Include Google Application Key for map downloading. The 1.4 release didn't have this key in the released version of the software, making map downloading fail for most people.

TeleGPS version 1.4

Version 1.4 is a major release. It includes support for our new TeleGPS product, new features and bug fixes in in the flight software for all our boards and the AltosUI ground station

AltOS New Features

  • Add support for TeleGPS boards.

  • Replace the 'dit dit dit' tones at startup with the current battery voltage, measured in tenths of a volt. This lets you check the battery voltage without needing telemetry, which is especially useful on EasyMini.

  • Change state beeping to "Farnsworth spacing", which means they're quite a bit faster than before, and so they take less time to send.

  • Make the beeper tone configurable, making it possible to distinguish between two Altus Metrum products in the same ebay.

  • Make the firing time for extra pyro channels configurable, allowing longer (or shorter) than the default 50ms. Only relevant for TeleMega at this time.

AltOS Fixes

  • Fix bug preventing the selection of the 'Flight State After' mode in pyro configuration.

  • Fix bug where erasing flights would reset the flight number to 2 on TeleMega and TeleMetrum v2.

  • Fix u-Blox GPS driver to mark course and speed data as being present.

AltosUI New Features

  • Add zooming and new content types (terrain and road maps) to map view. Change map storage format from PNG to Jpeg, which saves a huge amount of disk space. You will need to re-download all of your pre-loaded map images.

  • Add a distance measuring device to the maps view. Select this by using any button other than the left one, or by pressing shift or control on the keyboard while using the left button.

  • Add new 'Ignitor' tab to the flight monitor display for TeleMega's extra ignitors.

  • Increase the width of data lines in the graphs to make them easier to read.

  • Add additional ignitor firing marks and voltages to the graph so you can see when the ignitors fired, along with the ignitor voltages.

  • Add GPS course, ground speed and climb rate as optional graph elements.

AltosUI Fixes

  • When flashing new firmware, re-try opening the device as sometimes it takes a while for the underlying operating system to recognize that the device has rebooted in preparation for the flashing operation.

  • Hide Tilt Angle in ascent tab for devices that don't have a gyro.

  • Filter out speed and acceleration spikes caused by ejection charge firing when computing the maximum values. This provides a more accurate reading of those maximums.

  • Fix EasyMini voltage displays. Early EasyMini prototypes used a 3.0V regulator, and AltosUI still used that value as the basis of the computation. Production EasyMini boards have always shipped with a 3.3V regulator. Also, purple EasyMini boards sensed the battery voltage past the blocking diode, resulting in a drop of about 150mV from the true battery voltage. Compensate for that when displaying the value.

  • Display error message when trying to configure maximum flight log size while the flight computer still has flight data stored.

  • Handle TeleMetrum and TeleMini eeprom files generated with pre-1.0 firmware. Those ancient versions didn't report the log format, so just use the product name instead.

TeleGPS Application

  • New application designed for use with TeleGPS boards.

  • Shares code with AltosUI, mostly just trimmed down to focus on TeleGPS-related functions.

Documentation changes

  • Re-create the drill template images; they should print correctly from Firefox at least. Ship these as individual PDF files so they're easy to print.

  • Add a description of the 'Apogee Lockout' setting, which prevents the apogee charge from firing for a configurable amount of time after boost.


User View

  • GPS tracker and logger
  • Offers custom digital telemetry, APRS and direction beacons
  • 16mW transmit power
  • High-dynamics GPS receiver for accurate tracking
  • Uses 3.7V Lithium Polymer battery.
  • 1.5 x 1.0 inch board designed to fit inside 29mm airframe coupler tube
  • 2MB on-board data logging flash
  • Built-in USB connection for configuration, data download and battery charging
  • 12.3g flight weight (including antenna, excluding any battery)

Developer View

  • Hardware Features
    • NXP LPC11U14 System-on-Chip
      • ARM Cortex-M0 MCU
      • 32k Flash
      • 6k RAM
      • USB 2.0
      • 8 12-bit analog inputs
      • I2C, SPI, async serial
      • digital I/O
    • uBlox Max 7Q GPS receiver
    • TI CC115L 70cm transmitter
    • Built-in USB data download and battery charger connection
    • 2MB SPI flash
  • Software Features
    • Written mostly in C with some ARM assembler
    • Runs from on-chip flash, uses on-chip RAM, stores tracking data to flash memory part
  • Tools Used
    • gEDA for schematic capture and PCB layout
    • GCC compiler and source debugger
  • Licenses


There is a single manual for TeleGPS and all other Altus Metrum products, which is available in html and pdf formats.

The hardware design files can be found on in the project hw/telegps.