ModemManager Reference Manual: org.freedesktop.ModemManager1.Modem.Location

Properties

Capabilities     readable   u
Enabled          readable   u
SignalsLocation  readable   b
Location         readable   a{uv}

Description

The Location interface allows devices to provide location information to client applications. Not all devices can provide this information, or even if they do, they may not be able to provide it while a data session is active.

Method Details

The Setup() method

Setup (IN  u sources,
       IN  b signal_location);

Configure the location sources to use when gathering location information. Also enable or disable location information gathering. This method may require the client to authenticate itself.

When signals are emitted, any client application (including malicious ones!) can listen for location updates unless D-Bus permissions restrict these signals from certain users. If further security is desired, the signal_location argument can be set to FALSE to disable location updates via D-Bus signals and require applications to call authenticated APIs (like GetLocation() ) to get location information.

`IN u sources`:	Bitmask of MMModemLocationSource flags, specifying which sources should get enabled or disabled. MM_MODEM_LOCATION_SOURCE_NONE will disable all location gathering.
`IN b signal_location`:	Flag to control whether the device emits signals with the new location information. This argument is ignored when disabling location information gathering.

The GetLocation() method

GetLocation (OUT a{uv} Location);

Return current location information, if any. If the modem supports multiple location types it may return more than one. See the "Location" property for more information on the dictionary returned at location.

This method may require the client to authenticate itself.

OUT a{uv} Location:

Property Details

The "Capabilities" property

Capabilities  readable   u

Bitmask of MMModemLocationSource values, specifying the supported location sources.

The "Enabled" property

Enabled  readable   u

Bitmask specifying which of the supported MMModemLocationSource location sources is currently enabled in the device.

The "SignalsLocation" property

SignalsLocation  readable   b

TRUE if location updates will be emitted via D-Bus signals, FALSE if location updates will not be emitted.

See the Setup() method for more information.

The "Location" property

Location  readable   a{uv}

Dictionary of available location information when location information gathering is enabled. If the modem supports multiple location types it may return more than one here.

Note that if the device was told not to emit updated location information when location information gathering was initially enabled, this property may not return any location information for security reasons.

This dictionary is composed of a MMModemLocationSource key, with an associated data which contains type-specific location information:

MM_MODEM_LOCATION_SOURCE_3GPP_LAC_CI

Devices supporting this capability return a string in the format "MCC,MNC,LAC,CI" (without the quotes of course) where the following applies:

`MCC`	This is the three-digit ITU E.212 Mobile Country Code of the network provider to which the mobile is currently registered. e.g. `"310"`.
`MNC`	This is the two- or three-digit GSM Mobile Network Code of the network provider to which the mobile is currently registered. e.g. `"26"` or `"260"`.
`LAC`	This is the two-byte Location Area Code of the base station with which the mobile is registered, in upper-case hexadecimal format without leading zeros, as specified in 3GPP TS 27.007 section 10.1.19. e.g. `"84CD"`.
`CI`	This is the two- or four-byte Cell Identifier with which the mobile is registered, in upper-case hexadecimal format without leading zeros, as specified in 3GPP TS 27.007. e.g. `"2BAF"` or `"D30156"`.

The entire string may only be composed of the ASCII digits [0-9], the alphabetical characters [A-F], and the comma (,) character. No other characters are allowed. For example: "310,260,8BE3,2BAF" or "250,40,CE00,1CEAD8F0".

If any of these four items (MCC, MNC, LAC, CI) is unknown or the mobile is not registered with a network, then the MM_MODEM_LOCATION_SOURCE_3GPP_LAC_CI location information item should not be provided as a returned value from the GetLocation() method or in the "Location" property.

MM_MODEM_LOCATION_SOURCE_GPS_RAW

Devices supporting this capability return a D-Bus dictionary (signature "a{sv}") mapping well-known keys to values with defined formats.

The allowed key/value pairs and their formats are:

`"utc-time"`	(Required) UTC time in ISO 8601 format, given as a string value (signature `"s"`). e.g. `203015`.
`"latitude"`	(Required) Latitude in Decimal Degrees (positive numbers mean N quadrasphere, negative mean S quadrasphere), given as a double value (signature `"d"`). e.g. `38.889722`, meaning 38d 53' 22" N.
`"longitude"`	(Required) Longitude in Decimal Degrees (positive numbers mean E quadrasphere, negative mean W quadrasphere), given as a double value (signature `"d"`). e.g. `-77.008889`, meaning 77d 0' 32" W.
`"altitude"`	(Optional) Altitude above sea level in meters, given as a double value (signature `"d"`). e.g. `33.5`.

MM_MODEM_LOCATION_SOURCE_GPS_NMEA

Devices supporting this capability return a string containing one or more NMEA sentences (D-Bus signature 's'). The manager will cache the most recent NMEA sentence of each type for a period of time not less than 30 seconds. When reporting multiple NMEA sentences, sentences shall be separated by an ASCII Carriage Return and Line Feed (<CR><LF>) sequence.

For example, if the device sends a $GPRMC sentence immediately followed by a $GPGGA sentence, the reported location string would be (where of course the <CR><LF> is replaced with the actual ASCII CR (0x0D) and LF (0x0A) control characters):

$GPRMC,134523.92,V,,,,,,,030136,,,N*73<CR><LF>$GPGGA,,,,,,0,00,0.5,,M,0.0001999,M,0.0000099,0000*45

If the device sends a new $GPRMC three seconds later, the new $GPRMC replaces the previously received $GPRMC sentence, and the updated string would be:

$GPRMC,134526.92,V,,,,,,,030136,,,N*76<CR><LF>$GPGGA,,,,,,0,00,0.5,,M,0.0001999,M,0.0000099,0000*45

If the device then sends a $GPGSA sentence about 5 seconds later, the $GPGSA sentence is added to the string (since no $GPGSA sentence was obviously received in this session), the updated string would be:

$GPRMC,134526.92,V,,,,,,,030136,,,N*76<CR><LF>$GPGGA,,,,,,0,00,0.5,,M,0.0001999,M,0.0000099,0000*45<CR><LF>$GPGSA,A,1,,,,,,,,,,,,,1.1,0.5,1.0*34

The manager may discard any cached sentences older than 30 seconds.

This allows clients to read the latest positioning data as soon as possible after they start, even if the device is not providing frequent location data updates.

MM_MODEM_LOCATION_SOURCE_CDMA_BS