Fixposition Documentation
Fixposition Documentation
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FP_A-TF

Description:

This message contains the transformation (translation in Cartesian coordinates and rotation as a quaternion) from frame A to B.

Configuration:

  • FP_A-TF_POIIMUH transformation from the IMU horizontal frame to the sensor’s current attitude (roll, pitch, yaw). Mainly to provide an output of pitch and roll estimation before Fusion is available. Note: The estimation is degraded as only IMU is used to compute it.

  • FP_A-TF_VRTKCAM transformation from VRTK to camera

  • FP_A-TF_POIVRTK transformation from POI to VRTK

  • FP_A-TF_ECEFENU0 transformation from ECEF to ENU0 (available since 2.85.3)

  • FP_A-TF_POIPOISH transformation from POI to POISH (available since 2.85.3)

The frames are (see also https://docs.fixposition.com/fd/fixposition-ros-driver#FixpositionROSDriver-Explainationofframeids ):

  • VRTK: Coordinate Frame at the “X” logo of Vision-RTK2, with X pointing forward, Y pointing to the left and Z pointing up.

  • CAM: Camera coordinate frame, with X pointing to the left, Y pointing up and Z poiting to the direction of the optical axis

  • POI: “Point of Interest” The output coordinate frame with the user specified transformation from the VRTK frame to the frame of the output. By default it is the same as VRTK.

  • IMUH: IMU Horizontal, A local horizontal frame with the origin at the same location as FP_POI. This frame is a rough estimate determined by the IMU alone.

  • ENU0: Global-fixed East-North-Up coordinate frame. Its origin can be chosen as the first ODOMETRY position or configured manually.

Example messages: 

$FP,TF,2,2233,315835.000000,VRTK,CAM,-0.00000,-0.00000,-0.00000,1.000000,0.000000,0.000000,0.000000*6B\r\n
$FP,TF,2,2233,315835.000000,POI,VRTK,-0.99301,-2.01395,-2.99298,0.999995,-0.002616,-0.001748,-0.000868*52\r\n

Message fields:

#

Field

Format

Unit

Example

Description

1

msg_type

String

-

TF

Message type, always TF for this message

2

msg_version

Numeric

-

2

Message version, always 2 for this version of the TF message

3

gps_week

Numeric

-

2233

GPS week number, range 0–9999

4

gps_tow

Float (.6)

s

315835.000000

GPS time of week, range 0.000–604799.999999

5

frame_a

String

-

POI

Target frame (maximum 8 characters: A-Z and 0-9)

6

frame_b

String

-

VRTK

Initial frame (maximum 8 characters: A-Z and 0-9)

7

translation_x

Float (.5)

m

-0.99301

Translation, X component

8

translation_y

Float (.5)

m

-2.01395

Translation, Y component

9

translation_z

Float (.5)

m

-2.99298

Translation, Z component

10

orientation_w

Float (.6)

-

0.999995

Rotation in quaternion, W component

11

orientation_x

Float (.6)

-

-0.002616

Rotation in quaternion, X component

12

orientation_y

Float (.6)

-

-0.001748

Rotation in quaternion, Y component

13

orientation_z

Float (.6)

-

-0.000868

Rotation in quaternion, Z component