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Only released in EOL distros:   fuerte

ROS API

estimator

Node for producing state estimates from observed measurements. Position/attitude are essentially passed-through from the source data (i.e. Vicon measurements) and linear/angular velocity are simply derived by finite differencing with filtering.

Subscribed Topics

<transform_topic> (geometry_msgs/TransformStamped)

• Input data from Vicon (vicon_mocap/vicon_recv_direct). Actual topic name is specified by the ~transform_topic parameter.

Published Topics

~output (nav_msgs/Odometry)

• State (position, orientation, linear velocity and angular velocity) estimate of the vehicle (/<vehiclename>/flyer_imu frame, expressed in /ned frame).

Parameters

~transform_topic (str, default: "vicon_recv_direct/output")

• Topic to listen to for Vicon output.

~freq (int, default: 50)

• Rate in Hz at which to publish state estimates.

~xy_vel_filt_a (float, default: 0.9)

• Coefficient for linear velocity filter (x and y components).

~xy_vel_filt_b (float, default: 0.1)

• Coefficient for linear velocity filter (x and y components).

~z_vel_filt_a (float, default: 0.9)

• Coefficient for linear velocity filter (z component).

~z_vel_filt_b (float, default: 0.1)

• Coefficient for linear velocity filter (z component).

~ang_vel_filt_a (float, default: 0.9)

• Coefficient for angular velocity filter.

~ang_vel_filt_b (float, default: 0.1)

• Coefficient for angular velocity filter.

Required tf Transforms

/<vehiclename>/flyer_vicon → /<vehiclename>/flyer_imu

• Transform from vehicle's Vicon frame (segment) to flyer_imu frame. The flyer_imu frame should be at the center of the vehicle, in the plane of the IMU, with X pointing towards the forward (orange tape) prop, Y pointing starboard and Z pointing down. This transform is only looked up once at startup time and then subsequently used to transform incoming Vicon data on the vehicle's pose (which is expected to be /enu -> /<vehiclename>/flyer_vicon) to a preferable transform (/ned -> /<vehiclename>/flyer_imu).