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- | ==Hardware==
| + | This is a page outlining the capabilities and what is known of the GPS. |
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- | The [[:wikipedia:GPS|GPS]] in the [[Nokia N900|N900]] is a TI GPS5030 - navilink 5. [http://www.tessco.com/products/displayProductInfo.do?sku=365173&eventPage=3]
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| + | It may be a Navilink GPS, from TI. |
| The Navilink series is detailed [http://focus.ti.com/general/docs/wtbu/wtbugencontent.tsp?templateId=6123&navigationId=12028&contentId=4636 here]. | | The Navilink series is detailed [http://focus.ti.com/general/docs/wtbu/wtbugencontent.tsp?templateId=6123&navigationId=12028&contentId=4636 here]. |
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- | The GPS is not connected to the main CPU, but to the processor in the phone module, hence cannot be communicated with directly. [https://bugs.maemo.org/show_bug.cgi?id=7026#c35]
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- | It is connected through [[N900 Hardware Bus I2C|I2C]], and a 4 bit data connection, see [[N900_Hardware_Schematic#Page_10|Page 10 of the schematic]].
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- | The GPS uses approximately 50 mA when enabled, and logging once per second using [http://repository.maemo.org/pool/maemo5.0/non-free/l/location-test-gui/ location test GUI]. See also [[N900 Hardware Power Consumption]]
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- | ==Software==
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- | The GPS is driven through the [http://maemo.org/api_refs/5.0/5.0-final/liblocation/ liblocation] library, which supports several modes of location, some of which use the GPS, some use external data to improve lock times, and some that do not use the GPS at all.
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- | There are many user applications that use the GPS, from simple loggers, like [http://maemo.org/packages/view/gps-data-logger/ GPS data logger] to [http://osm.org openstreetmap] [http://maemo.org/packages/view/osm2go editors] and even [http://www.sygic.com/index.php/en/press-releases/press-news/300-sygic-mobile-maps-for-nokia-n900-maemo-available-for-purchase.html commercial replacements for the free Ovi maps software].
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- | == Phonet Protocol ==
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- | See [[N900_GPS_Reverse_Engineering]]
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- | ==Accuracy==
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- | Over a long period in one position with a clear view of the sky, the horizontal accuracy is outlined in this graph.
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- | * 50% of points within 2.4m
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- | * 90% within 4.2m
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- | * 99% within 18m
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- | * 99.9% within 80m.
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- | [[Image:N900gps-0-95%25.gif|Percentage points falling within the given radius in decimeters (1/10th of a meter)]]
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- | The outliers are explored in detail here.
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- | [[Image:N900gps-95-100%25.gif]]
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- | [[Image:N900gps-99-100%.gif]]
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- | ==Bugs== | + | ===User reports of lock times=== |
| + | With software GPSjinni (from extras-devel) |
| + | * Lock time after 12h or more of no GPS, with no cell, and no wifi active. |
| + | ** Indoors >10 min - 2 signals strong, but no lock - no time fix reported. |
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- | A number of users have reported poor or no lock in circumstances where the phone should obtain a GPS lock. See [https://bugs.maemo.org/show_bug.cgi?id=7026 this (now closed) bug] for more information and if you are still affected by this. (read all of the bug carefully)
| + | * Lock time after 12h or more of no GPS, with no cell, and wifi active. |
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- | [[Category:N900]]
| + | * Lock time after 12h or more of no GPS with cell active, but no data connection. |
- | [[Category:N900 Hardware]]
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