Radar Yaw-Rate Estimation from Single-Scan Target Detections
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Solution Overview
Problem
Existing radar systems lack an efficient method for instantaneous estimation of full planar motion parameters, particularly yaw-rate, of rigid body targets using raw detections from a single radar measurement instance, which is crucial for autonomous driving applications.
Innovation Solution
A method that calculates yaw-rate by determining the center of rotation and position of a target vehicle using a combination of Least Square solutions and geometric interpretations from range, azimuth, and range rate measurements, allowing for the estimation of longitudinal and lateral velocities and yaw-rate from a single radar measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If instantaneous estimation of full planar motion parameters is achieved using a single radar measurement instance, then measurement precision and speed are improved, but device complexity and computational complexity increase
Solution Approach 1:
The patent segments the complex motion estimation problem into distinct computational stages: (1) extracting motion parameters from raw radar detections, (2) determining the center of rotation through geometric intersection of lines, and (3) calculating yaw-rate from the segmented motion components. This segmentation allows the system to process information in manageable steps rather than attempting simultaneous full-motion estimation.
Solution Approach 2:
The patent introduces the center of rotation as an intermediary concept that mediates between raw radar measurements and final yaw-rate estimation. By first determining the center of rotation through line intersections (using orientation angle and range rate data), the system creates an intermediate reference point that simplifies the subsequent yaw-rate calculation, reducing overall computational complexity.
2Loss of information
If full planar motion parameters are estimated from raw radar detections, then information completeness is improved, but difficulty of detecting and measuring increases
Solution Approach 1:
The patent makes the radar system multi-functional by enabling it to extract multiple motion parameters (longitudinal velocity, lateral velocity, orientation angle, center of rotation, and yaw-rate) from the same set of raw detections. The range, azimuth, and range rate measurements serve multiple purposes in the calculation chain, allowing one radar system to perform comprehensive motion analysis without requiring additional sensors.
Solution Approach 2:
The patent replaces complex mechanical measurement systems with radar-based electromagnetic detection. Instead of using multiple physical sensors or mechanical gauges to measure motion parameters, the system uses radar signals to obtain range, azimuth, and range rate data, which are then processed to derive all motion parameters. This substitution simplifies the physical measurement setup while maintaining information completeness.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables accurate and instantaneous estimation of target vehicle yaw-rate and motion parameters, reducing computational complexity and improving robustness for real-time applications in autonomous driving systems.
Implementation Method 1
a) emitting a radar signal at a single time-point instance and determining, from a plurality (m) of point radar detections measurements captured from said target vehicle by said radar sensor unit in a single radar measurement instance, the values for each point detection of range, azimuth and range rate
Data Source
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AI summary
A method of determining the yaw rate (ω̂t) of a target vehicle in a horizontal plane by a host vehicle equipped with a radar system, said radar system including a radar sensor unit adapted to receive signals emitted from said host vehicle by said target, comprising: emitting a radar signal at a single time-point instance and determining from a plurality (m) of point radar detections measurements captured from said target vehicle by said radar sensor unit in said single radar measurement instance, the values for each point detection of range, azimuth and range rate; [ri, θi, ṙi]; determining the values of the longitudinal and lateral components of the range rate equation of the target (ct, st) from the results (ṙi, θi,) and the sensor unit or host vehicle longitudinal velocity and vs is the sensor unit or host vehicle lateral velocity; determining the orientation angle of the target (γt,scs); determining the target centre (xt and yt) from the results (ri, θi) ;determining a line lPH perpendicular to the orientation of the target and passing through the center of the target (xt,c,scs, yt,c,scs) ;determining a line lCA passing through the center of rotation of said target and the position of radar sensor unit of said vehicle; determining the intersection point of the lines lCA and lPH being the position of the center of rotation [x̂t,COR, ŷt,COR] of the target; h) estimating and yaw rate ω̂t from the position of the centre of rotation found in step f) and components of range rate equation of the target (ct or st) of step b).