it would be very nice, if you could add additional information in the GPX file output. Especially speed would be very nice eg for biketracking and also running, because GPS speed information is much more accurate than calculating it from position distances especially at low speeds. As there is no standard speed tag in GPX 1.1 you could use GPX extensions like they are common from garmin devices and also locus maps usese them, like this:
<?xml version="1.0" encoding="utf-8" standalone="yes"?>
<gpx version="1.1" creator="Locus Android"
xmlns="http://www.topografix.com/GPX/1/1">http://www.topografix.com/GPX/1/1 "
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">http://www.w3.org/2001/XMLSchema-instance "
xsi:schemaLocation="http://www.topografix.com/GPX/1/1">http://www.topografix.com/GPX/1/1 http://www.topografix.com/GPX/1/1/gpx.xsd">http://www.topografix.com/GPX/1/1/gpx.xsd "
xmlns:gpxx="http://www.garmin.com/xmlschemas/GpxExtensions/v3">http://www.garmin.com/xmlschemas/GpxExtensions/v3 "
xmlns:gpxtrkx="http://www.garmin.com/xmlschemas/TrackStatsExtension/v1">http://www.garmin.com/xmlschemas/TrackStatsExtension/v1 "
xmlns:gpxtpx="http://www.garmin.com/xmlschemas/TrackPointExtension/v1">http://www.garmin.com/xmlschemas/TrackPointExtension/v1 "
xmlns:locus="http://www.locusmap.eu">http://www.locusmap.eu ">
<trk>
<name><![CDATA[2014-01-30 16:20:21]]></name>
<desc><![CDATA[0h:01m:57s | 8.0 m]]></desc>
<trkseg>
<trkpt lat="48.xxx" lon="16.xxx">
<ele>226.70</ele>
<time>2014-01-30T15:20:17Z</time>
<pdop>14.00</pdop>
<extensions>
<gpxtpx:TrackPointExtension>
<gpxtpx:speed>0.0</gpxtpx:speed>
</gpxtpx:TrackPointExtension>
</extensions>
</trkpt>
....
Maybe the dilution of precision tag could also be helpful.
In the locus maps forum there is also a discussion concerning this topic:
best regards