Vehicle Radar Ghost Detection Using Alternating Chirp Cycles
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Solution Overview
Problem
Radar systems face issues with velocity ambiguity and generate folding ghosts when tracking multiple objects, leading to erroneous recognition of stationary objects as moving, causing unnecessary warnings and vehicle control.
Innovation Solution
A radar apparatus with a transmitting unit and receiving unit that alternates chirp cycles to detect target objects, calculates velocity residuals, and determines folding ghosts based on evaluation values derived from velocity residual variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If velocity measurement is performed using phase rotation of frequency components, then velocity detection capability is improved, but velocity ambiguity and folding ghosts occur causing measurement precision to deteriorate
Solution Approach 1:
The radar apparatus performs velocity measurements at multiple different repetition cycles (first repetition cycle and second repetition cycle). By alternating between different periodic measurement intervals, the system can distinguish true velocity values from folded velocity values, as folding artifacts manifest differently at different repetition cycles while true velocities remain consistent.
Solution Approach 2:
The system calculates velocity residuals by comparing measured velocities across different repetition cycles and uses this feedback information to evaluate and identify folding ghosts. The velocity residual analysis provides feedback that enables the system to correct velocity measurements and eliminate false detections caused by velocity folding.
2Quantity of substance
If multiple objects are tracked simultaneously, then target detection coverage is improved, but folding ghosts increase causing reliability to deteriorate
Solution Approach 1:
By performing tracking measurements at alternating repetition cycles, the system creates temporal variations in how folding artifacts appear for different targets. This periodic measurement approach allows the system to distinguish between real targets and folding ghosts through velocity residual analysis, maintaining reliability even when tracking multiple objects simultaneously.
Solution Approach 2:
The velocity residual calculation acts as an intermediary evaluation mechanism that mediates between multiple target measurements and the final target identification. This intermediary process filters out folding ghosts by comparing velocity measurements across different repetition cycles, ensuring reliable target identification regardless of the number of tracked objects.
3Difficulty of detecting and measuring
If stationary objects are detected using the same velocity measurement method, then detection sensitivity is improved, but false detection of stationary objects as moving increases causing harmful factors to worsen
Solution Approach 1:
The system uses alternating repetition cycles to detect stationary objects, where true stationary objects consistently show zero velocity across all cycles while false detections (folding ghosts) exhibit varying velocity values. This periodic measurement approach enables the system to maintain high detection sensitivity while eliminating false warnings through velocity residual evaluation.
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
Effectively distinguishes between actual and folding ghosts, reducing unnecessary warnings and vehicle control by accurately identifying stationary objects as such.
Implementation Method 1
The transmitting unit transmits a transmission signal that is a pulse signal or a chirp signal
Implementation Method 2
The receiving unit receives a reflection signal that is generated by the transmission signal transmitted by the transmitting unit being reflected by at least one object
Implementation Method 3
when the relative velocity is calculated from a phase rotation of a frequency component that is continuously detected for the same object
Data Source
AI summary
A radar apparatus, mounted to a vehicle, includes: a transmitting unit that transmits a transmission signal at a set repetition cycle; and a receiving unit that receives a reflection signal reflected by at least one object. The radar apparatus calculates a velocity residual of each of at least one target object, which is a difference between a velocity prediction value and a velocity measurement value. Based on a magnitude of variation in the velocity residual in time series of each of at least one target object, the radar apparatus calculates an evaluation value of each of at least one target object, which corresponds to a probability of each of at least one target object being a folding ghost. Based on the evaluation value of each of at least one target object, the radar apparatus determines whether each of at least one target object is a folding ghost.