2D Velocity Vector Estimation Using Multiple Radar Doppler Measurements
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Solution Overview
Problem
A single radar system cannot detect the tangential component of an object's velocity vector, providing incomplete information about the object's velocity, as it only measures radial velocity.
Innovation Solution
A method and system using multiple radars to obtain Doppler frequency measurements and angular locations, generating a coarse velocity estimate, and forming a likelihood map to select the most likely velocity hypothesis from a search grid based on entropy and energy differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single radar is used to measure velocity, then the device complexity is reduced, but the measurement precision is insufficient because only radial velocity can be detected
Solution Approach 1:
The patent combines multiple radar systems to work together as an integrated velocity measurement system. Each radar provides Doppler frequency measurements and angular location data, and these measurements are merged through processing to compute both radial and tangential velocity components, achieving complete 2D velocity vector measurement.
Solution Approach 2:
The patent transitions from measuring only radial velocity (one dimension) to measuring the complete 2D velocity vector by utilizing angular location information from multiple radars. This adds the tangential velocity component, transforming the measurement capability from 1D to 2D velocity space.
2Measurement precision
If multiple radars are deployed to measure both radial and tangential velocity components, then the measurement precision improves, but the device complexity increases
Solution Approach 1:
The patent makes the multiple radar system perform multiple functions: each radar not only measures radial velocity through Doppler frequency but also provides angular location information. By combining these functions across multiple radars, the system achieves 2D velocity vector measurement without requiring separate dedicated sensors for each measurement type.
3Measurement precision
If velocity hypotheses are evaluated using likelihood maps with entropy and energy terms, then the measurement precision of velocity estimation is improved, but the loss of time increases due to complex processing
Solution Approach 1:
The patent performs preliminary actions by generating a search grid based on coarse velocity estimates before conducting the detailed likelihood evaluation. This preliminary structuring of the velocity hypothesis space allows the system to focus computational resources on the most probable velocity ranges, reducing the overall processing time while maintaining precision.
Solution Approach 2:
The patent replaces traditional mechanical or direct optimization methods with an information-theoretic approach using entropy and energy terms from likelihood maps. This substitution allows for parallel evaluation of multiple velocity hypotheses and identifies the most likely velocity vector through information theoretic metrics rather than iterative mechanical optimization.
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 the determination of a two-dimensional velocity vector of an object, improving navigation by providing complete velocity information for autonomous vehicles.
Implementation Method 1
obtaining a measurement of Doppler frequency for the object at each of a plurality of spaced apart radars
Data Source
AI summary
A vehicle, system and method of estimating a velocity of an object with respect to the vehicle is disclosed. The system includes a plurality of radars associated with the vehicle and a processor. The plurality of radars provide a coarse estimate of the velocity. The processor obtains a plurality of velocity hypotheses based on the coarse estimate of the velocity of the object, determines a likelihood for each of the plurality of velocity hypotheses, and chooses a velocity hypothesis having as the estimate of velocity based on the determined likelihood.