Introduction
Roadnav is an open source street navigation solution capable of running on a variety of operating systems. It can obtain your position from a GPS unit, plot a map of your area, and provide directions to locations in the USA. It can also verbalize directions using Microsoft SAPI 5.1, Festival, flite, and OS X's built in text to speech engine.
Homepage: http://roadnav.sourceforge.net/
Download: http://roadnav.sourceforge.net/downloads.php
Possible Usefulness
RoadNav is limited to tracking one object via either a serial port (NMEA data), or a network (GPSD server). The Ground Station team is using RoadNav to test our vehicle tracking capabilities. The reason for doing this is that RoadNav provides real time driving directions and maps. It also include a handy search features which can give us detailed step by step directions while we're driving. (which we've never had before)
Testing Results
Through the use of RoadNav the Ground Station team has been able to successfully test parts of our GPS data network involving the GPSd application. We have been able to establish a high confidence in the reported position data with our internally mounted GPS receiver, and see many aspects of our positional accuracy within the RoadNav interface. We were also able to find shortcomings in the design of RoadNav and have plans to contact the software development team to address some of those issues.
Future Plans
We plan on using RoadNav for its search and directions capabilities, in conjunction with our new prototype tracking system, GERTTS. In addition we will continue to develop our tracking system with backwards compatibility and Operating System agnosticism in mind.
Current Progress
Known Issue - RoadNav doesn't automatically reconnect to GPSd if it losses connection temporarily.
According to their ChangeLog this functionality was added in Version 0.12 (1/2/06), but it was likely removed in Version 0.15 (8/18/06) on accident when they "[s]witched from libgps to a custom gpsd interface" because we are not experiencing this functionality in the Version 0.18 of the software. There was recently a Version 0.19 of RoadNav released, but from the ChangeLog it does not appear to address this issue. We will do more testing, and submit a bug report if this new version of the RoadNav software does not reconnect to our GPSd server upon losing its connection. Because we usually get disconnected from the GPSd server with RoadNav with an unknown error in 20-30 minute intervals, reconnecting automatically is important in order to continue logging GPS data or plot our course in real time.
Another person having the same issue
Searching the roadnav mailing list archives, I saw that another user noticed the same behavior and requested a similar solution. In May 2007 Dustin Spicuzza asks for an auto-reconnect for gpsd.
… For example, say your GPS unit goes screwy or something.. like most hardware devices, resetting it would do the trick, right? So, you unplug and plug the thing back in.. but by that time, Roadnav has disabled GPS. Then you have to go back into Roadnav and set the GPS information up again.. Makes little sense…
Is there a good rationale for this behavior? Otherwise, I'd say lets change it so it keeps retrying like.. every second or 5 seconds or something — at least for the GPSD module, I don't really care about the other ones ;) …
Searching the roadnav TODO for version 0.20, we notice that our described issue is not on the list. It is likely that the roadnav development team is unaware of this problem.
Conclusion
Based on this information, we will try to open a ticket on the source forge project site to see if this issue can be corrected or changed. It will likely happen in the 0.21 release, which may be many months away. We may have to modify the source code for RoadNav ourselves to get the behavior that we want (an auto-reconnect instead of disabling of the GPS source) before the next mission. Hopefully our GERTTS application will be ready by this time in case we cannot solve this RoadNav behavior issue.
- Update: A feature request ticket has been filed. (10-17-09)
Known Issue - RoadNav can't save tracking data.
RoadNav cannot save tracking data to a file to be accessed later. It does not appear to be a feature on their TODO list, so it won't be showing up anytime soon. It is likely that as an application designed to help people driving cars to find directions, RoadNav won't be interested in saving previous routes taken. We currently use another application to record data from our GPSd server to get around this issue.
