Google has recently fixed a couple of bugs in the Google Maps API code, and both map controls and events have suddenly started working using the iPhone web browser. I've put them back in now, and the real-time APRS map is suddenly much more functional. Thanks for the little Christmas present, Google!
Look for me on HF digital modes during the Christmas holidays, I'm trying to be active from a few countryside locations.
The news of https://aprs.fi/ - new features and interesting attractions found in the APRS and AIS worlds.
Sunday, December 21, 2008
gnuais 0.1.0 released
gnuais 0.1.0 can now be downloaded from SourceForge. It's an AIS decoding program for Linux, licensed under the GPL. Attach it to the 9600-bit/s data capable discriminator output of a VHF FM receiver, tune the rx on the marine VHF channel 87B (161.975 MHz) or 88B (162.025 MHz), and you'll be able to receive position data from nearby vessels.
Version 0.1.0 has an improved DSP decoder (thanks to Tomi Manninen, OH2BNS) and it can also upload AIS data to aprs.fi using the new JSON AIS protocol. If you wish to share your AIS data with aprs.fi, please drop me an email - the address is on the Profile page of this blog.
This is still an alpha quality release, so there are some caveats - the local GUI isn't working, and SoundChannels should be set to both (other settings will probably not work). The installation instructions are not very good either. If you've compiled software on Linux before, set up an igate, and played with soundmodem or gmfsk, installing should be pretty easy. It's an open-source project, so contributions are welcome!
Version 0.1.0 has an improved DSP decoder (thanks to Tomi Manninen, OH2BNS) and it can also upload AIS data to aprs.fi using the new JSON AIS protocol. If you wish to share your AIS data with aprs.fi, please drop me an email - the address is on the Profile page of this blog.
This is still an alpha quality release, so there are some caveats - the local GUI isn't working, and SoundChannels should be set to both (other settings will probably not work). The installation instructions are not very good either. If you've compiled software on Linux before, set up an igate, and played with soundmodem or gmfsk, installing should be pretty easy. It's an open-source project, so contributions are welcome!
Saturday, December 20, 2008
AIS data exchange with MarineTraffic
We've recently started mutually exchanging AIS data with MarineTraffic.com. aprs.fi gets AIS data from MarineTraffic, and MarineTraffic gets what we have. This improves the coverage of both services significantly, as there wasn't much overlap before.
The peering is still being tested and the protocol improved, so it might be a bit flaky for a while, but generally it seems to work.
We're not converting AIS data to APRS format, and it is not my intention to do so - too much valuable information would be lost in the conversion process, and the APRS-IS network simply is not there for this purpose.
We've specified a new JSON based protocol which is also useful for feeding AIS data from receiving stations to these services. There is already a working Perl implementation for converting an NMEA AIS stream to the JSON AIS protocol for uplinking to aprs.fi, it's currently being tested on a couple of receiving sites. I'm hoping the author of the client will release it in the near future.
The peering is still being tested and the protocol improved, so it might be a bit flaky for a while, but generally it seems to work.
We're not converting AIS data to APRS format, and it is not my intention to do so - too much valuable information would be lost in the conversion process, and the APRS-IS network simply is not there for this purpose.
We've specified a new JSON based protocol which is also useful for feeding AIS data from receiving stations to these services. There is already a working Perl implementation for converting an NMEA AIS stream to the JSON AIS protocol for uplinking to aprs.fi, it's currently being tested on a couple of receiving sites. I'm hoping the author of the client will release it in the near future.
Friday, October 31, 2008
gnuais - AIS decoding on Linux
Lately I've been working on the gnuais source code, improving it so that it could be used to decode AIS and feed aprs.fi using Linux. My changes are in the SVN trunk (not in any released version yet). It's generally working, I just haven't done the actual "feed aprs.fi" part yet. But it's getting closer. The decoder isn't as good as in aismon/shipplotter - if you have DSP coding experience, your help is welcome on this project!
I've also modified some Televa 703-LYVV VHF FM receivers from the cold war era to be used as AIS receivers. "Brand new" (but a bit over 30 years old - like myself) commercial NBFM receivers in their original factory boxes, built to be installed at bomb shelters and such, but (luckily) never needed. Going to install a couple of them here in Helsinki, with directional antennas pointing southeast and southwest on the Gulf of Finland. We installed the antennas and cables during the last couple weeks, they're just waiting for the gnuais feeding code.
I've also modified some Televa 703-LYVV VHF FM receivers from the cold war era to be used as AIS receivers. "Brand new" (but a bit over 30 years old - like myself) commercial NBFM receivers in their original factory boxes, built to be installed at bomb shelters and such, but (luckily) never needed. Going to install a couple of them here in Helsinki, with directional antennas pointing southeast and southwest on the Gulf of Finland. We installed the antennas and cables during the last couple weeks, they're just waiting for the gnuais feeding code.
aprs.fi presentation video
In June I gave a presentation on aprs.fi at the 30th Nordic VHF/UHF/SHF-meeting in Sappee, Finland. You can now view the presentation video on the Internet. The slides are also available in PDF format. I'm not very proud of it, with a little practice and slightly less stuttering the same amount of information could be condensed to maybe 30% of the time. Well, something to improve for the next presentation...
If you'd like me to give a presentation somewhere next summer, let me know (at least 3 months in advance, please). I'll be happy to come, if you can cover the travel expenses, and find me a bunk bed to sleep in.
If you'd like me to give a presentation somewhere next summer, let me know (at least 3 months in advance, please). I'll be happy to come, if you can cover the travel expenses, and find me a bunk bed to sleep in.
Thursday, October 9, 2008
iPhone & iPod Touch support greatly enhanced
I went ahead and bought an iPod Touch (Apple's opinion) for debugging my little aprs web project. The Touch is basically an iPhone (Apple propaganda) - without the phone and the camera. It's much cheaper, but it has the same operating system, web browser, and can run the same applications, so it's fine for the purpose. I got the new second generation 16GB model (with external volume controls, speaker, etc), around 300 EUR ($400 USD). It's very pretty, and the user interface is very cool indeed.I did a little debugging yesterday evening and tonight, and fixed a few rough corners which broke things for iPhone users. The fixes should help other mobile browsers, too. All of the pages should now render properly on the iPhone & Touch. The real-time map now loads new items nicely, and handles panning of the map. The map controls (zoom, satellite/terrain/map buttons) do not work, but that's a bug in Google's code, and they know about it already.
The changes I did in the real-time map code had an interesting side effect which benefits all users. When you pan the map on a normal web browser, targets coming in the view load a bit quicker, and the overall experience is slightly smoother than before. What a nice surprise.
The bad news is that it seems quite hard to make the real-time map work on the S60 browser, at least on my E61i (the static map works fine, of course). It simply blows up, probably runs out of memory. Maybe it could work on Nokia's new Linux-based products. Too bad I don't have one to debug with.
I'll get back to this some another day. A lot of stuff needs to be done (a nicer front page with address search, etc).
Sunday, October 5, 2008
Preferences localisation
I just moved all the strings in the options window in the string database, making it possible to translate that part of the user interface. I also changed the name of that window from Options to Preferences, to match common user interface terminology.This weekend I've been playing with a lift we rented. Yesterday I installed snow guards on the roof - 2*6m of tube secured near the edge, designed to keep snow and ice from falling down. Makes spring-time access to our front door a bit safer.
The feed of my 40m/20m butterfly dipole is also visible in this photo.
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