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api: revise and simplify Location spec

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Simplify the NMEA type and add GPS raw for generic GPS data.
This commit is contained in:
Dan Williams
2010-05-19 23:33:33 -07:00
parent ef747c6385
commit 481b6539b4
1 changed files with 65 additions and 24 deletions
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89
introspection/mm-modem-location.xml
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@@ -117,43 +117,37 @@
providing GPS NMEA-format location information.</p> providing GPS NMEA-format location information.</p>
<p>For location reporting, devices supporting this capability return <p>For location reporting, devices supporting this capability return
an array mapping timestamps to specific NMEA sentences (D-Bus a string containing one or more NMEA sentences (D-Bus signature 's').
signature 'a(ss)'). The manager will cache the most recent NMEA The manager will cache the most recent NMEA sentence of each type for
sentence of each type for a period of time not less than 30 seconds a period of time not less than 30 seconds. When reporting multiple
and must indicate the time that sentence was receieved from the device NMEA sentences, sentences shall be separated by an ASCII Carriage
using the timestamp. Timestamps are provided as strings in the "Unix Return and Line Feed (&lt;CR&gt;&lt;LF&gt;) sequence.
epoch" format (i.e. number of seconds since 1970-01-01 00:00:00 UTC
with microsecond resolution if available).
</p> </p>
<p> <p>
For example, if at time 1268336242.282202 the device sends a $GPRMC For example, if the device sends a $GPRMC sentence immediately
sentence immediately followed by a $GPGGA sentence, the reported followed by a $GPGGA sentence, the reported location string would be
location array would be: (where of course the &lt;CR&gt;&lt;LF&gt; is replaced with the actual
ASCII CR (0x0D) and LF (0x0A) control characters):
<pre> <pre>
[ '1268336242.282202': '$GPRMC,134523.92,V,,,,,,,030136,,,N*73', $GPRMC,134523.92,V,,,,,,,030136,,,N*73&lt;CR&gt;&lt;LF&gt;$GPGGA,,,,,,0,00,0.5,,M,0.0001999,M,0.0000099,0000*45
'1268336242.282202': '$GPGGA,,,,,,0,00,0.5,,M,0.0001999,M,0.0000099,0000*45' ]
</pre> </pre>
If the device sends a new $GPRMC three seconds later, the new $GPRMC If the device sends a new $GPRMC three seconds later, the new $GPRMC
replaces the previously received $GPRMC sentence, and the updated array replaces the previously received $GPRMC sentence, and the updated
would be: string would be:
<pre> <pre>
[ '1268336245.282202': '$GPRMC,134526.92,V,,,,,,,030136,,,N*76', $GPRMC,134526.92,V,,,,,,,030136,,,N*76&lt;CR&gt;&lt;LF&gt;$GPGGA,,,,,,0,00,0.5,,M,0.0001999,M,0.0000099,0000*45
'1268336242.282202': '$GPGGA,,,,,,0,00,0.5,,M,0.0001999,M,0.0000099,0000*45' ]
</pre> </pre>
If the device then sends a $GPGSA sentence about 5 seconds later, the If the device then sends a $GPGSA sentence about 5 seconds later, the
$GPGSA sentence is added to the array (since no $GPGSA sentence was $GPGSA sentence is added to the string (since no $GPGSA sentence was
previously received in this session), the updated array would be: previously received in this session), the updated string would be:
<pre> <pre>
[ '1268336245.282202': '$GPRMC,134526.92,V,,,,,,,030136,,,N*76', $GPRMC,134526.92,V,,,,,,,030136,,,N*76&lt;CR&gt;&lt;LF&gt;$GPGGA,,,,,,0,00,0.5,,M,0.0001999,M,0.0000099,0000*45&lt;CR&gt;&lt;LF&gt;$GPGSA,A,1,,,,,,,,,,,,,1.1,0.5,1.0*34
'1268336242.282202': '$GPGGA,,,,,,0,00,0.5,,M,0.0001999,M,0.0000099,0000*45'
'1268336250.395423': '$GPGSA,A,1,,,,,,,,,,,,,1.1,0.5,1.0*34' ]
</pre> </pre>
The manager may discard any entries older than 30 seconds. The manager may discard any cached sentences older than 30 seconds.
</p> </p>
<p>This allows clients to read the latest positioning data as soon as <p>This allows clients to read the latest positioning data as soon as
possible after they start, even if the device is not providing possible after they start, even if the device is not providing
frequent location data updates. Using the timestamp the client can frequent location data updates.
determine which data is most relevant to its particular uses.
</p> </p>
</tp:docstring> </tp:docstring>
</tp:flag> </tp:flag>
@@ -205,6 +199,53 @@
GetLocation() method or in the Location property.</p> GetLocation() method or in the Location property.</p>
</tp:docstring> </tp:docstring>
</tp:flag> </tp:flag>
<tp:flag suffix="GSM_GPS_RAW" value="0x4">
<tp:docstring>
<p>For capability reporting, indicates the device is capable of
providing raw GPS information using a series of defined key/value
pairs.</p>
<p>For location reporting, devices supporting this
capability return a D-Bus dict (signature a{sv}) mapping well-known
keys to values with defined formats. The allowed key/value pairs
and their formats are:</p>
<table>
<tr><th>Key</th><th>Value Type</th><th>Value contents</th><th>Example</th></tr>
<tr>
<td>latitude</td>
<td>d</td>
<td>Latitude in Decimal Degrees (positive numbers mean N quadrasphere, negative mean S quadrasphere)</td>
<td>38.889722 (ie, 38d 53' 22" N)</td>
</tr>
<tr>
<td>longitude</td>
<td>d</td>
<td>Longitude in Decimal Degrees (positive numbers mean E quadrasphere, negative mean W quadrasphere)</td>
<td>-77.008889 (ie, 77d 0' 32" W)</td>
</tr>
<tr>
<td>altitude</td>
<td>d</td>
<td>Altitude above sea level in meters</td>
<td>33.5</td>
</tr>
<tr>
<td>horiz-velocity</td>
<td>d</td>
<td>Horizontal velocity in meters-per-second</td>
<td>.5</td>
</tr>
<tr>
<td>vert-velocity</td>
<td>d</td>
<td>Vertical velocity in meters-per-second</td>
<td>.01</td>
</tr>
</table>
<p>The 'latitude' and 'longitude' keys are required; other keys are
optional.</p>
</tp:docstring>
</tp:flag>
</tp:flags> </tp:flags>
</interface> </interface>