Firefox OS/Geolocation

API

Firefox OS geolocation API is the W3C Standard API at http://dev.w3.org/geo/api/spec-source.html

Usage

The underlying implementation can be different for different hardware providers. As a developer, you should be transparent to the underlying implementation, and write apps using the APIs which specifies whether you want enableHighAccuracy or not. eg:

• if you are writing a navigation app, which needs accuracy upto a few meters, then enableHighAccuracy=TRUE.
• If you are writing a weather app which just needs w coarse location, then your app can consume less power by enableHighAccuracy=FALSE.

Commercial Implementations

Mozilla does not produce Firefox OS images for commercial devices-- we provide source code to chip manufacturers and OEMs. These parties customize various parts and create binary images for devices. The final Firefox OS image is mostly representative of what we have in the public source repositories. This is an important distinction because the configuration of some parts (like linux config, device setup, etc) is not in Mozilla's hands.

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.

Details

The geolocation provider use a few different method to compute location based on the environment:

1. Satellite - Uses GPS Receiver to locate the device.
2. Network methods - Uses nearby WiFi Access points and Cell towers

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.

1. 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:

1. SUPL: Standardized
2. 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.