FMCW Radar Object Detection Message Format

This document describes a standardized message format for transmitting object data detected by FMCW radar sensors. This format is designed to be used within a robotics or autonomous system context, particularly with the ARS 408 millimeter-wave radar.

Message Structure

The message comprises the following fields:

unique_identifier_msgs/UUID uuid            # Unique object ID generated by the radar

geometry_msgs/Point position                # x, y, z coordinates of the object's centroid (z is ignored for 2D tracking)
geometry_msgs/Vector3 velocity              # Object velocity in each spatial dimension
geometry_msgs/Vector3 acceleration          # Object acceleration in each spatial dimension
geometry_msgs/Vector3 size                  # Object dimensions (e.g., length, width, height, or ellipsoid diameter)

uint16 classification                       # Object classification (see below)

float32[6] position_covariance              # Upper-triangle covariance matrix for position (x, y, z)
float32[6] velocity_covariance              # Upper-triangle covariance matrix for velocity (x, y, z)
float32[6] acceleration_covariance          # Upper-triangle covariance matrix for acceleration (x, y, z)
float32[6] size_covariance                  # Upper-triangle covariance matrix for size (x, y, z)

Object Classifications

The 'classification' field uses the following codes:

uint16 NO_CLASSIFICATION=0
uint16 STATIC=1
uint16 DYNAMIC=2

Vendor-specific classifications are allowed starting from 32000.

Coordinate Frame

All variables are relative to the radar's frame of reference. Coordinate transformations may be required to obtain real-world positions and velocities.

Usage with ARS 408 Radar

Refer to the ARS 408 API documentation or user manual for specific implementation details. Typically, this message would be incorporated as part of a larger data structure or array for transmission and parsing.

Key points to remember when using this message with the ARS 408:

• Coordinate Transformation: Convert coordinates and velocities from the radar's frame to the desired reference frame.
• Covariance Matrices: Utilize the provided covariance matrices to assess the uncertainty and reliability of the radar measurements.

This standardized message format helps ensure interoperability and simplifies the integration of FMCW radar data into various systems and applications.