Tuesday, August 31, 2010

iPad location sharing, bugfixes and Android support

I've installed a couple of fixes in the web locations updating code now. It failed to work for about 6 unlucky users due to a little bug which didn't take database replication delays into account. But that's sorted now.

I've also put the 'share location' button on the non-mobile site, so that it can be used on the iPad and other larger devices with GPS. We'll see what effect that has!

The good news is that it seems to work on several Android phones:
  • Google Nexus One
  • HTC Dream
  • HTC Espresso
  • Samsung Galaxy S
  • Motorola Droid
  • LG Ally
It'll probably work on the rest of the new ones with GPS, too.
The new tool buttons are now documented in the manual.

Web location uploads, better iPhone support, and favourite stations

I've just installed a rather large upgrade on the production aprs.fi servers. As usual, some things might break, in which case you'll get to keep both pieces, but it should be worth it.

The system now supports uploading positions directly to aprs.fi using a web browser which supports the W3C Geolocation API. In practice this means that you can update your location using a mobile phone which has a GPS and a modern web browser. No native application or purchase is required. I have only tested this with the iPhone (OS 3.0 and newer), but there is a good chance that Android phones will work, too. To try this out, create an user account on aprs.fi, log in from the phone, and click on the transmitting tower button to upload your position.

You can also click on the crosshair button to center the map on your current GPS coordinates. Naturally, your web browser will ask you whether your position can be revealed to aprs.fi before either of these functions are enabled.

The positions are not transmitted to or via the APRS-IS, so it is OK for users without amateur radio licenses to upload their positions, too. The stations are identified as web stations on aprs.fi, for example: oh7lzb föni (my iPhone). Web stations names are not restricted by AX.25 / APRS limitations, and can contain spaces and international characters.

The names of the web stations live in a separate namespace from APRS and AIS stations. There can be a 'N0CALL' phone as well as a 'N0CALL' APRS station, and a 'N0CALL' AIS ship. When names overlap, the web site will let you pick the right station from a list. Multiple web stations may also share the same name, which should help avoid collisions.

The mobile version of the map has been improved to better support the iPhone. With some luck, these improvements should also help on Android and other new powerful mobile devices, but I haven't tested it on one yet. I really haven't used anything iPhone-specific which would intentionally break on other devices (I have tested the mobile version of the site on Firefox to validate this), but only testing will tell. Feedback is welcome.

I've also added a favourite stations list. The 'star' button to show the bookmark list is visible, but the editing functionality has not been published yet. Stay tuned for more!

Monday, August 16, 2010

aprs.fi in Chinese

BA5AG has done a lot of work to translate aprs.fi in simplified Chinese (简体字). The simplified characters are currently used in Mainland China, Singapore and Malaysia, and this translation makes aprs.fi and APRS in general accessible to a huge new audience (besides adding one more way to confuse myself while using my own software). A big thank you to Weng Kai for his volunteer effort!

Tuesday, August 3, 2010

Device Identification, and a rate advisor fix

I've just installed support for APRS device identification. The info page now makes an attempt to show the type of tracker or software being used by the station. The identification data collection started just a few minutes ago, so most stations are still not identified, but they're getting identified as packets are transmitted. The identification happens when position packets are received, so you'll need to send some packets to update the identification. For example, here's an VX-8G:


As a nice side effect the comment fields of mic-e stations are getting cleaned up from the device identification characters.

I've also updated the packet rate advisor to use an arithmetic mean of the packet transmit interval instead of a median. Some stations which sent two packets in a row (with 2 seconds between the 2 packets) every 30 minutes (giving an average interval of 15 minutes) sometimes quite correctly got a 2-second median interval, and got a "very high rate" warning.

The APRS packet parser was upgraded to Ham::APRS::FAP version 1.16 (to support the device identification).