AltOS — The Altus Metrum Operating System

Altos is the core of the software for all of the Altus Metrum products. It runs on the 8051-based micro-controllers within both the flight computer and the ground station devices. AltOS a small cooperatively multi-tasking operating system.

AltOS Version 0.7.1 Released

Bdale and I have just released AltOS version 0.7.1. Version 0.7.1 is the first release to include the new Java-based ground station software which runs on Linux, Mac OS X and various Windows flavors.

AltOS Changes in 0.7.1

  1. Deal with Windows and Mac OSX USB stacks. These two operating systems do “interesting” things with USB and found some boundary conditions within the AltOS USB stack which couldn't be tested on Linux. With test cases discovered, the ‘panic’ calls were turned into code that dealt with these cases correctly.

  2. Increase packet mode payload size and add callsigns. The callsigns are set by the ‘master’ end of the packet link (normally the TeleDongle) so that the entire radio conversation conforms to regulatory requirements. Increasing the payload size makes data transfers go faster.

  3. Place configuration data in fixed flash addresses. This change makes it possible to read the serial number and radio calibration data back out of the flash data when reprogramming a device.

TeleMetrum Changes in 0.7.1

  1. Ensure GPS date information is written to on-board data logger. The GPS date information is used when constructing eeprom log file names; without this, the eeprom downloading tool would generate a filename based on the current date.

  2. Allow TeleMetrum to be used as a programming dongle. This means the user can reprogram a TeleDongle or another TeleMetrum using the TeleMetrum as a programming dongle. Before this, only the TeleDongle could be used to program other devices.

AltosUI - Ground Station Software for Altus Metrum devices

Version 0.7.1 is the first release containing our new cross-platform Java-based user interface. AltosUI can:

  • Receive and log telemetry from a connected TeleDongle device. All data received is saved to log files named with the current date and the connected rocket serial and flight numbers. There is no mode in which telemetry data will not be saved.

  • Download logged data from TeleMetrum devices, either through a direct USB connection or over the air through a TeleDongle device.

  • Configure a TeleMetrum device, setting the radio channel, callsign, apogee delay and main deploy height. This can be done through either a USB connection or over a radio link via a TeleDongle device.

  • Replay a flight in real-time. This takes a saved telemetry log or eeprom download and replays it through the user interface so you can relive your favorite rocket flights.

  • Reprogram Altus Metrum devices. Using an Altus Metrum device connected via USB, another Altus Metrum device can be reprogrammed using the supplied programming cable between the two devices.

  • Export Flight data to a comma-separated-values file. This takes either telemetry or on-board flight data and generates data suitable for use in external applications. All data is exported using standard units so that no device-specific knowledge is needed to handle the data.

  • Speak to you during the flight. Instead of spending the flight hunched over your laptop looking at the screen, enjoy the view while the computer tells you what's going on up there. During ascent, you hear the current flight state and altitude information. During descent, you get azimuth, elevation and range information to try and help you find your rocket in the air. Once on the ground, the direction and distance are reported.

Three Operating Systems, One AltosUI

AltosUI provides all of these features on the three target operating systems, Linux, Mac OS X (version 10.5 or newer) and Windows (XP, Vista or 7). The bulk of the software is written in Java and is built once and tested and delivered on all three target platforms. A tiny ‘shim’ library is built on each system to provide access to the Altus Metrum devices connected over the USB link.

Thanks to our contributors!

We've gotten lots of help getting this software built and tested:

  • Tim Van Milligan at Apogee Components helped shake out portability and installation issues on Mac OS X and Windows Vista

  • Adrian Adamson from Featherweight Altimeters helped with Windows install adventures as well as fixing data export from telemetry files after unfortunately losing eeprom data in a field in Kansas.

  • Bob Finch has written a bunch of our documentation, provided packaging files for Arch Linux along with helping debug general Linux compatibility issues.

Future Plans

With the basic AltOS and AltosUI functionality running, we've got lots of ideas about where to take the system in the future. And, we'd love to hear ideas from you as well. Some of the ideas we've like to get done include:

  1. Google Earth file export. We had a Linux-based C program to export a ‘KML’ (Keyhole Markup Language) file that Google Earth can read and present to the user overlayed on satellite photo data.

  2. Data Plotting. Being able to plot flight data right in the UI would be nice, and there are several Java plotting packages available to try out.

  3. State-dependent display. When the rocket is on the pad, you only want to know if it's ready to fly. When the rocket is descending on a chute, you want to know where it is in the sky and how fast its falling. Presenting a limited amount of information that is most likely interesting to the user should make the display more useful.

  4. Ejection charge testing. The TeleMetrum firmware has the ability to fire ejection charges over the USB or radio links. Safely hooking this up to the user interface will allow for wireless ejection system testing. The key here is “safely”, of course, which means figuring out a ‘fool proof’ user interface.

I'm sure there are any number of additions that could be made to this list; feel free to send along ideas that you've got. Of course, all of this software is licensed under the GNU General Public License, so you can get the source and hack on it in the comfort of your own home.