Firefox OS/Geolocation: Difference between revisions

Firefox OS/Geolocation (view source)

Revision as of 19:10, 24 April 2015

130 bytes added , 24 April 2015

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AGPS cleanup

Rdandu

canmove, Confirmed users

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 So, to recap -- some pieces are NOT under Mozilla's control and one of them is the geolocation configuration.  It is completely up to the chip manufacturers and OEM to correctly configure a-gps.
-==AGPS==
+==Details==
-The configuration of a-gps is in two parts.  The first part is in Gecko.  B2G/gaia currently uses supl 1.0 with cell fallback.  We have code in our geolocation provider that informs the modem that an agps server is located at a QC supl1 server.  We do this by calling an API and pass only a FQDN and a port.  The other part that needs to be configured is the “modem”.  The modem needs to be configured with TLS enabled and the certificate of the QC supl1 server.  Mozilla does NOT have any way to configure the modem and OEMs are encouraged to discuss this with their chip manufacturer.  (I am using QC here because as of this writing, that is who we are using.  If you are using another chip manufacturer you'll have to work with them on an a-gps service).
+The geolocation provider use a few different method to compute location based on the environment:
+)Satellite - Uses GPS Receiver  to locate the device.
+)Network methods - Uses nearby WiFi Access points and Cell towers
-So, to recap – Mozilla does not ship binaries.  Mozilla does not configure Modems.  If you are shipping devices, you must ensure that a-gps is configured properly.  Configuration of a-gps is completely outside of the scope of Firefox OS.
+These two methods complement each other to improve geolocation
+Availability: GPS works well in open sky, where Network methods are not as accurate. Network methods work well in deep indoor, where GPS does not work well. Having both increases availability.
+Time To First Fix: GPS is accurate, and take some time, while Network is coarse and is faster. Network location can be used by GPS to opti
+===AGPS===
+For the Satellite fixes, GPS is used. To shorten the searching for satellites, methods for assistance are used. Some of them are:
+) SUPL: Standardized
+) Proprietary Extended Ephemeris solutions: GPS HW providers implement optimizations.
+So, to recap – Mozilla does not ship binaries.  Mozilla does not configure Modems.  If you are shipping devices, you must ensure that a-gps is configured properly with the HW provider.  Configuration of a-gps is completely outside of the scope of Firefox OS.