Difference between revisions of "Module/GPS UBlox UCenter"

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(Be quick when you want to capture the debug message.)
 
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__TOC__
<categorytree style="float:right; clear:right; margin-left:1ex; border: 1px solid gray; padding: 0.7ex;" mode=pages>Modules</categorytree>
<categorytree style="float:right; clear:right; margin-left:1ex; border: 1px solid gray; padding: 0.7ex;" mode=pages>Modules</categorytree>
If you use a µ-blox GPS whithout flash memory, this module will take over the task of initializing the GPS for you when you power your autopilot.  
If you use a µ-blox GPS without flash memory, this module will take over the task of initializing the GPS for you when you power your autopilot.
The module also figures out the current speed of the GPS and setup the communication from the AP accordingly:
 
It has auto-baudrate to detect the current GPS baudrate, and configures all message rates and communication ports. The module will send a DEBUG message (ID 26) that indicates the firmware version in your GPS, the previous baudrate, and the reply for each configuration step. To enable and view the message, you will need to define DEBUG_GPS_UBX_UCENTER as TRUE in your [[Airframe_Configuration|airframe configuration]] file. See the example below for more details.
 
It will configure the following settings:
* set baudrate to GPS_BAUD (typically either 38400 or 57600)
* enable the NAV_POSLLH, NAV_VELNED, NAV_STATUS, NAV_SVINFO, NAV_SOL
* disable UTM on old Lea4P by not sending NAV_POSUTM
* enable SBAS
* configure it to 3D only fix
* set the internal dynamic model to Airborne 2G
 
 
== Basic ==


Add the gps_ubx_ucenter [[Modules|module]] to the "modules" section in your aircraft configuration file:
Add the gps_ubx_ucenter [[Modules|module]] to the "modules" section in your aircraft configuration file:
{{Box Code|conf/airframes/myplane.xml|
<source lang="xml">
<source lang="xml">
   <modules>
   <modules>
Line 10: Line 24:
   </modules>
   </modules>
</source>
</source>
}}
== Advanced ==
You can specify to a different dynamic model for the u-blox.
{{Box Code|conf/airframes/myplane.xml|
<source lang="xml">
  <modules>
    ...
    <load name="gps_ubx_ucenter.xml">
<define name="GPS_UBX_NAV5_DYNAMICS" value="NAV5_DYN_PORTABLE" />
    </load>
  </modules>
</source>
}}
'''Additional details on GPS_UBX_NAV5_DYNAMICS'''


In some cases, you will need to specify which UART of the GPS you are using. The tiny/ppzgps use ublox_internal_port1 (the default) but if for instance you use a LS-SAM or I2C device you need to configure:
The ublox GPS uses a dynamics model (motion model) to filter the noisy GPS readings and produce smoother results. The dynamics
model will affect what positions and speeds are accurately tracked by GPS. Generally, it is recommend to use NAV5_DYN_PORTABLE for quadcopters and NAV5_DYN_AIRBORNE_2G for fixed wings.


The follow is taken from the ublox protocol specification document:
u-blox positioning technology supports different dynamic platform models to adjust the navigation engine to
the expected application environment. These platform settings can be changed dynamically without performing
a power cycle or reset. The settings improve the receiver's interpretation of the measurements and thus provide
a more accurate position output. Setting the receiver to an unsuitable platform model for the given application
environment results in a loss of receiver performance and position accuracy.
{| border="1"
|+ '''Dynamic Platform Model'''
|-
! scope="row" | NAV5_DYN_PORTABLE
| Applications with low acceleration, e.g. portable devices. Suitable for most situations. MAX Altitude [m]: 12000, MAX Velocity [m/s]: 310, MAX Vertical Velocity [m/s]: 50, Sanity check type: Altitude and Velocity, Max Position Deviation: Medium
|-
! scope="row" | NAV5_DYN_STATIONARY
| Used in timing applications (antenna must be stationary) or other stationary applications. Velocity restricted to 0 m/s. Zero dynamics assumed. MAX Altitude [m]: 9000, MAX Velocity [m/s]: 10, MAX Vertical Velocity [m/s]: 6, Sanity check type: Altitude and Velocity, Max Position Deviation: Small
|-
! scope="row" | NAV5_DYN_PEDESTRIAN
| Applications with low acceleration and speed, e.g. how a pedestrian would move. Low acceleration assumed. MAX Altitude [m]: 9000, MAX Velocity [m/s]: 30, MAX Vertical Velocity [m/s]: 20, Sanity check type: Altitude and Velocity, Max Position Deviation: Small
|-
! scope="row" | NAV5_DYN_AUTOMOTIVE
| Used for applications with equivalent dynamics to those of a passenger car. Low vertical acceleration assumed. MAX Altitude [m]: 6000 (5000 for firmware versions 6.00 and below), MAX Velocity [m/s]: 84 (62 for firmware versions 4.00 to 5.00), MAX Vertical Velocity [m/s]: 15, Sanity check type: Altitude and Velocity, Max Position Deviation: Medium
|-
! scope="row" | NAV5_DYN_SEA
| Recommended for applications at sea, with zero vertical velocity. Zero vertical velocity assumed. Sea level assumed. MAX Altitude [m]: 500, MAX Velocity [m/s]: 25, MAX Vertical Velocity [m/s]: 5, Sanity check type: Altitude and Velocity, Max Position Deviation: Medium
|-
! scope="row" | NAV5_DYN_AIRBORNE_1G
| Used for applications with a higher dynamic range and vertical acceleration than a passenger car. No 2D position fixes supported. MAX Altitude [m]: 50000, MAX Velocity [m/s]: 100, MAX Vertical Velocity [m/s]: 100, Sanity check type: Altitude, Max Position Deviation: Large
|-
! scope="row" | NAV5_DYN_AIRBORNE_2G
| Recommended for typical airborne environment. No 2D position fixes supported. MAX Altitude [m]: 50000, MAX Velocity [m/s]: 250, MAX Vertical Velocity [m/s]: 100, Sanity check type: Altitude, Max Position Deviation: Large
|-
! scope="row" | NAV5_DYN_AIRBORNE_4G
| Only recommended for extremely dynamic environments. No 2D position fixes supported. MAX Altitude [m]: 50000, MAX Velocity [m/s]: 500, MAX Vertical Velocity [m/s]: 100, Sanity check type: Altitude, Max Position Deviation: Large
|}
== Debug ==
You can specify to receive a DEBUG message over telemetry by enabling it in your airframe file:
{{Box Code|conf/airframes/myplane.xml|
<source lang="xml">
<source lang="xml">
   <modules>
   <modules>
     ...
     ...
     <load name="gps_ubx_ucenter.xml">
     <load name="gps_ubx_ucenter.xml">
<define name="GPS_PORT_ID" value="GPS_PORT_UART2" />
<define name="GPS_UBX_NAV5_DYNAMICS" value="NAV5_DYN_PORTABLE" />
<define name="DEBUG_GPS_UBX_UCENTER" value="TRUE" />
     </load>
     </load>
   </modules>
   </modules>
</source>
</source>
}}
The DEBUG message has the following information:
* [0] Initial baudrate high
* [1] Initial baudrate low.  For example if the baud rate is 9600 you will see 9,6
* [2] ublox software verision high
* [3] ublox software version low
* [4] ublox hardware version high
* [5] ublox hardware version low
* [6] Always 0
* [7] Success of setting CFG-NAV5. For all of these a value of 0 indicates no response, 1 is success and 2 is command rejected by GPS.
* [8] Success of enable NAV-POSLLH
* [9] Success of enable NAV-VELNED
* [10] Success of enable NAV-STATUS
* [11] Success of enable NAV-SVINFO
* [12] Success of enable NAV-SOL
* [13] Success of disabling NAV-POSUTM (typically fails to 0 for non LEA-4P modules)
* [14] Success of enable SBAS
* [15] Success of setting CFG-RATE
* [16] Success of setting RXM-RAW (typically disabled - see USE_GPS_UBX_RXM_RAW flag to enable)
* [17] Success of setting RXM-SFRB (typically disabled - see USE_GPS_UBX_RXM_SFRB flag to enable)
* [18] Success of saving configuration to ublox memory
The debug message is '''sent only once''' a few seconds after powering on. Make sure to have messages displayed before powering on to make sure to capture it. If you get all zeroes then check cabling and try again. Make sure RX from the GPS is connected to TX on the autopilot.


[[Category:User_Documentation]] [[Category:Modules]]
[[Category:User_Documentation]] [[Category:Modules]]

Latest revision as of 09:40, 10 October 2015

Modules
ArduIMU
Module/ADC generic
Module/Aeroprobe OTF
Module/Airspeed ETS
Module/AOA adc
Module/Bosch BMP085
Module/collective tracking control
Module/FlightBenchmark
Module/Freescale MPL3115A2
Module/GPS UBlox UCenter
Module/guidance vector field
Module/Honeywell HIH-4030
Module/Hygrosens TEMOD-I2C-R1
Module/infrared
Module/IST DigiPicco
Module/LM75
Module/Mag HMC58xx
Module/Meas Spec MS5611 I2C
Module/Melexis MLX90614
Module/rl obstacle avoidance
Module/Rotorcraft cam
Module/Sensirion SHT25
Module/Sensirion SHT75
Module/Servo switch
Module/System monitor
Module/TI TMP102
Module/TronSens HTM B71
Module/VTI SCP1000 I2C
Module/VTI SCP1000 SPI
Modules
Modules list
MultiUAV
Openlog
Pan Tilt Camera
SDLogger SPI Direct
Sensors/AMSYS

If you use a µ-blox GPS without flash memory, this module will take over the task of initializing the GPS for you when you power your autopilot.

It has auto-baudrate to detect the current GPS baudrate, and configures all message rates and communication ports. The module will send a DEBUG message (ID 26) that indicates the firmware version in your GPS, the previous baudrate, and the reply for each configuration step. To enable and view the message, you will need to define DEBUG_GPS_UBX_UCENTER as TRUE in your airframe configuration file. See the example below for more details.

It will configure the following settings:

  • set baudrate to GPS_BAUD (typically either 38400 or 57600)
  • enable the NAV_POSLLH, NAV_VELNED, NAV_STATUS, NAV_SVINFO, NAV_SOL
  • disable UTM on old Lea4P by not sending NAV_POSUTM
  • enable SBAS
  • configure it to 3D only fix
  • set the internal dynamic model to Airborne 2G


Basic

Add the gps_ubx_ucenter module to the "modules" section in your aircraft configuration file:

File: conf/airframes/myplane.xml 
  <modules>
    ...
    <load name="gps_ubx_ucenter.xml"/>
  </modules>


Advanced

You can specify to a different dynamic model for the u-blox.

File: conf/airframes/myplane.xml 
  <modules>
    ...
    <load name="gps_ubx_ucenter.xml">
	<define name="GPS_UBX_NAV5_DYNAMICS" value="NAV5_DYN_PORTABLE" />
    </load>
  </modules>

Additional details on GPS_UBX_NAV5_DYNAMICS

The ublox GPS uses a dynamics model (motion model) to filter the noisy GPS readings and produce smoother results. The dynamics model will affect what positions and speeds are accurately tracked by GPS. Generally, it is recommend to use NAV5_DYN_PORTABLE for quadcopters and NAV5_DYN_AIRBORNE_2G for fixed wings.

The follow is taken from the ublox protocol specification document:

u-blox positioning technology supports different dynamic platform models to adjust the navigation engine to the expected application environment. These platform settings can be changed dynamically without performing a power cycle or reset. The settings improve the receiver's interpretation of the measurements and thus provide a more accurate position output. Setting the receiver to an unsuitable platform model for the given application environment results in a loss of receiver performance and position accuracy.

Dynamic Platform Model
NAV5_DYN_PORTABLE Applications with low acceleration, e.g. portable devices. Suitable for most situations. MAX Altitude [m]: 12000, MAX Velocity [m/s]: 310, MAX Vertical Velocity [m/s]: 50, Sanity check type: Altitude and Velocity, Max Position Deviation: Medium
NAV5_DYN_STATIONARY Used in timing applications (antenna must be stationary) or other stationary applications. Velocity restricted to 0 m/s. Zero dynamics assumed. MAX Altitude [m]: 9000, MAX Velocity [m/s]: 10, MAX Vertical Velocity [m/s]: 6, Sanity check type: Altitude and Velocity, Max Position Deviation: Small
NAV5_DYN_PEDESTRIAN Applications with low acceleration and speed, e.g. how a pedestrian would move. Low acceleration assumed. MAX Altitude [m]: 9000, MAX Velocity [m/s]: 30, MAX Vertical Velocity [m/s]: 20, Sanity check type: Altitude and Velocity, Max Position Deviation: Small
NAV5_DYN_AUTOMOTIVE Used for applications with equivalent dynamics to those of a passenger car. Low vertical acceleration assumed. MAX Altitude [m]: 6000 (5000 for firmware versions 6.00 and below), MAX Velocity [m/s]: 84 (62 for firmware versions 4.00 to 5.00), MAX Vertical Velocity [m/s]: 15, Sanity check type: Altitude and Velocity, Max Position Deviation: Medium
NAV5_DYN_SEA Recommended for applications at sea, with zero vertical velocity. Zero vertical velocity assumed. Sea level assumed. MAX Altitude [m]: 500, MAX Velocity [m/s]: 25, MAX Vertical Velocity [m/s]: 5, Sanity check type: Altitude and Velocity, Max Position Deviation: Medium
NAV5_DYN_AIRBORNE_1G Used for applications with a higher dynamic range and vertical acceleration than a passenger car. No 2D position fixes supported. MAX Altitude [m]: 50000, MAX Velocity [m/s]: 100, MAX Vertical Velocity [m/s]: 100, Sanity check type: Altitude, Max Position Deviation: Large
NAV5_DYN_AIRBORNE_2G Recommended for typical airborne environment. No 2D position fixes supported. MAX Altitude [m]: 50000, MAX Velocity [m/s]: 250, MAX Vertical Velocity [m/s]: 100, Sanity check type: Altitude, Max Position Deviation: Large
NAV5_DYN_AIRBORNE_4G Only recommended for extremely dynamic environments. No 2D position fixes supported. MAX Altitude [m]: 50000, MAX Velocity [m/s]: 500, MAX Vertical Velocity [m/s]: 100, Sanity check type: Altitude, Max Position Deviation: Large

Debug

You can specify to receive a DEBUG message over telemetry by enabling it in your airframe file:

File: conf/airframes/myplane.xml 
  <modules>
    ...
    <load name="gps_ubx_ucenter.xml">
	<define name="GPS_UBX_NAV5_DYNAMICS" value="NAV5_DYN_PORTABLE" />
	<define name="DEBUG_GPS_UBX_UCENTER" value="TRUE" />
    </load>
  </modules>

The DEBUG message has the following information:

  • [0] Initial baudrate high
  • [1] Initial baudrate low. For example if the baud rate is 9600 you will see 9,6
  • [2] ublox software verision high
  • [3] ublox software version low
  • [4] ublox hardware version high
  • [5] ublox hardware version low
  • [6] Always 0
  • [7] Success of setting CFG-NAV5. For all of these a value of 0 indicates no response, 1 is success and 2 is command rejected by GPS.
  • [8] Success of enable NAV-POSLLH
  • [9] Success of enable NAV-VELNED
  • [10] Success of enable NAV-STATUS
  • [11] Success of enable NAV-SVINFO
  • [12] Success of enable NAV-SOL
  • [13] Success of disabling NAV-POSUTM (typically fails to 0 for non LEA-4P modules)
  • [14] Success of enable SBAS
  • [15] Success of setting CFG-RATE
  • [16] Success of setting RXM-RAW (typically disabled - see USE_GPS_UBX_RXM_RAW flag to enable)
  • [17] Success of setting RXM-SFRB (typically disabled - see USE_GPS_UBX_RXM_SFRB flag to enable)
  • [18] Success of saving configuration to ublox memory

The debug message is sent only once a few seconds after powering on. Make sure to have messages displayed before powering on to make sure to capture it. If you get all zeroes then check cabling and try again. Make sure RX from the GPS is connected to TX on the autopilot.

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