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Diffstat (limited to 'host/docs/gpsdo.rst')
| -rw-r--r-- | host/docs/gpsdo.rst | 41 |
1 files changed, 22 insertions, 19 deletions
diff --git a/host/docs/gpsdo.rst b/host/docs/gpsdo.rst index f732aae63..a41e23df6 100644 --- a/host/docs/gpsdo.rst +++ b/host/docs/gpsdo.rst @@ -11,11 +11,11 @@ to the Jackson Labs Firefly-1A device unless noted otherwise. ------------------------------------------------------------------------ Specifications ------------------------------------------------------------------------ -* Receiver type: 50 channel with WAAS, EGNOS, MSAS -* 10MHz ADEV: 1e-11 over >24h -* 1PPS RMS jitter: <50ns 1-sigma -* Holdover: <11us over 3h -* Phase noise: +* **Receiver type**: 50 channel with WAAS, EGNOS, MSAS +* **10MHz ADEV**: 1e-11 over >24h +* **1PPS RMS jitter**: <50ns 1-sigma +* **Holdover**: <11us over 3h +* **Phase noise**: * **1Hz:** -80dBc/Hz * **10Hz:** -110dBc/Hz @@ -25,25 +25,28 @@ Specifications **Antenna Types:** -The GPSDO is capable of supplying a 3V for active GPS antennas or supporting passive antennas +The GPSDO is capable of supplying a 3V for active GPS antennas or supporting passive antennas. ------------------------------------------------------------------------ -Installation instructions +Installation Instructions ------------------------------------------------------------------------ Installation instructions can be found here: -`www.ettus.com/downloads/gpsdo-kit.pdf <http://www.ettus.com/downloads/gpsdo-kit.pdf>`_ +`http://www.ettus.com/content/files/gpsdo-kit_datasheet.pdf <http://www.ettus.com/content/files/gpsdo-kit_datasheet.pdf>`_ ******************************************** -Post installation task (N-Series only) +Post-installation Task (N-Series only) ******************************************** -This is necessary if you require absolute GPS time in your application, + +**Note:** The following instructions are only necessary for UHD 3.4.* and below. + +This is necessary if you require absolute GPS time in your application or need to communicate with the GPSDO to obtain location, satellite info, etc. -If you only require 10MHz and PPS signals for reference or MIMO use, +If you only require 10MHz and PPS signals for reference or MIMO use (see the `Synchronization Application Notes <./sync.html>`_), it is not necessary to perform this step. To configure the USRP to communicate with the GPSDO, use the -usrp_burn_mb_eeprom utility: +**usrp_burn_mb_eeprom** utility: :: @@ -54,7 +57,7 @@ usrp_burn_mb_eeprom utility: ./usrp_burn_mb_eeprom --args=<optional device args> --key=gpsdo --val=none ------------------------------------------------------------------------ -Using the GPSDO in your application +Using the GPSDO in Your Application ------------------------------------------------------------------------ By default, if a GPSDO is detected at startup, the USRP will be configured to use it as a frequency and time reference. The internal VITA timestamp @@ -62,8 +65,8 @@ will be initialized to the GPS time, and the internal oscillator will be phase-locked to the 10MHz GPSDO reference. If the GPSDO is not locked to satellites, the VITA time will not be initialized. -GPS data is obtained through the mboard_sensors interface. To retrieve -the current GPS time, use the "gps_time" sensor: +GPS data is obtained through the **mboard_sensors** interface. To retrieve +the current GPS time, use the **gps_time** sensor: :: @@ -71,10 +74,10 @@ the current GPS time, use the "gps_time" sensor: The returned value will be the current epoch time, in seconds since January 1, 1970. This value is readily converted into human-readable -format using the time.h library in C, boost::posix_time in C++, etc. +format using the **time.h** library in C, **boost::posix_time** in C++, etc. Other information can be fetched as well. You can query the lock status -with the "gps_locked" sensor, as well as obtain raw NMEA sentences using -the "gps_gprmc", and "gps_gpgga" sensors. Location -information can be parsed out of the "gps_gpgga" sensor by using gpsd or +with the **gps_locked** sensor, as well as obtain raw NMEA sentences using +the **gps_gprmc**, and **gps_gpgga** sensors. Location +information can be parsed out of the **gps_gpgga** sensor by using **gpsd** or another NMEA parser. |