UWB Following Service Interface

UWB Raw Data Subscription Interface

Description

This interface is used to subscribe to the /uwb_data topic in ROS2 in order to receive coordinate data feedback from the UWB wristband.

Topic Name	Topic Type (Custom Message)	Role
/uwb_data	uwb_sensor_msgs::msg::UwbDataWithTimestamp	Subscriber

Message Structure

The message type uwb_sensor_msgs::msg::UwbDataWithTimestamp contains the following fields:

• x_position: Represents the X-axis coordinate of the tag relative to the anchor, in centimeters (cm).
• y_position: Represents the Y-axis coordinate of the tag relative to the anchor, in centimeters (cm).
• distance: Represents the 2D Euclidean distance between the tag and the anchor, in centimeters (cm).
• phase: Represents the angle (phase) of the tag relative to the anchor, in degrees (°).

Callback Example Message

void uwb_callback( 
    const uwb_sensor_msgs::msg::UwbDataWithTimestamp::SharedPtr msg) {
    if(msg->distance ==0 && msg->phase ==0 )
    {
        uwb_updated_ = false;
    }else
    {
        msg->distance = (msg->distance)*0.01;

        RCLCPP_INFO(this->get_logger(),
        "Received UWB data: dis: '%f m', phase: '%f deg'",
        msg->distance, msg->phase);
    }
}

Testing Method

• To print UWB topic /uwb_data in real time, use the following command in the terminal:

ros2 topic echo /uwb_data

• To analyze the publishing frequency of the UWB data in real time, use:

ros2 topic hz /uwb_data

Precautions

If the output shows error messages or remains empty, it is most likely due to the custom message type not being part of the standard ROS 2 library.
Before running the above commands, make sure to source the workspace:

source install/setup.bash