Bug 89907 - Get speed & heading from NMEA RMC sentences
Summary: Get speed & heading from NMEA RMC sentences
Alias: None
Product: GeoClue
Classification: Unclassified
Component: General (show other bugs)
Version: unspecified
Hardware: Other All
: medium normal
Assignee: Geoclue Bugs
QA Contact: Geoclue Bugs
Depends on:
Reported: 2015-04-05 10:44 UTC by Fabrice Bellet
Modified: 2018-05-06 14:36 UTC (History)
0 users

See Also:
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Description Fabrice Bellet 2015-04-05 10:44:38 UTC
It may be more interesting to use data from $GPRMC NMEA sentences to obtain speed directly from GPS output, instead of processing it based on two consecutive location updates :  http://aprs.gids.nl/nmea/#rmc  (speed over ground, knots). 

The rationale is that NMEA updates from ModemManager over DBUS are scheduled every 30 seconds, even if the NMEA stream from hardware is updated more frequently. In such case, processing information obtained from previous location  will provide an average speed over the last 30 secs, while $GPRMC data may provide an instantaneous speed every 30 secs.
Comment 1 Zeeshan Ali 2015-06-18 13:58:38 UTC
Also heading. :)
Comment 2 Bastien Nocera 2015-06-18 14:13:45 UTC
The heading from the GPS is the heading of the course. If you were stopped and turned your device, you wouldn't see good enough information.

We can read magnetic variation in that NMEA sentence though.
Comment 3 GitLab Migration User 2018-05-06 14:36:53 UTC
-- GitLab Migration Automatic Message --

This bug has been migrated to freedesktop.org's GitLab instance and has been closed from further activity.

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