Radar Device Velocity Aliasing Correction via Up-Down Chirp Analysis
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Solution Overview
Problem
Current FCM radar devices face limitations in accurately detecting relative velocity due to aliasing issues and require high sampling frequency hardware, which is restrictive in terms of size, weight, and cost, making it difficult to achieve detection velocity ranges and resolutions comparable to FM-CW systems.
Innovation Solution
The radar device employs a transmission signal with alternating up and down periods, allowing for the computation of distances and relative velocities using both up-side and down-side distances, and includes an aliasing determining unit to correct for velocity aliasing, enabling accurate relative velocity measurement even beyond the detection range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high sampling frequency hardware is used to achieve accurate velocity detection, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The transmission signal is segmented into multiple chirps within each period, with each chirp contributing to distance and velocity information. By processing multiple segmented signals through FFT operations, the system achieves high measurement precision without requiring high sampling frequency hardware, thus resolving the contradiction between accuracy and hardware complexity
Solution Approach 2:
The patent transitions from time-domain sampling to frequency-domain analysis by performing FFT on the received signals. This dimensional transformation allows velocity detection through frequency analysis of beat signals rather than requiring high-time-resolution sampling, thereby achieving accurate velocity measurement with simpler hardware
2Speed
If FCM system uses short chirp period to increase detection velocity range, then speed is improved, but measurement precision deteriorates due to aliasing
Solution Approach 1:
The system performs FFT analysis on beat signals to extract frequency information, then uses this frequency data to calculate velocity. The feedback loop processes multiple chirps and applies aliasing correction algorithms to resolve velocity ambiguity, enabling accurate velocity measurement across extended ranges without requiring longer chirp periods
Solution Approach 2:
The patent changes the approach from direct time-domain velocity measurement to frequency-domain analysis through FFT. By transforming the measurement parameter from time-based sampling to frequency-based spectral analysis, the system extends detection velocity range while maintaining precision through mathematical processing rather than hardware improvements
3Adaptability or versatility
If FM-CW system is used to achieve wide detection range, then adaptability is improved, but device complexity increases compared to FCM
Solution Approach 1:
The FCM system is designed to perform both distance measurement and velocity detection using the same hardware configuration and signal processing pipeline. By making the system universal in its capabilities, it achieves detection range comparable to FM-CW without increasing device complexity, as both functions are integrated into a single coherent system architecture
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
This approach allows for accurate relative velocity detection across a wider range without the need for high sampling frequency hardware, effectively overcoming aliasing limitations and achieving performance comparable to FM-CW systems.
Implementation Method 1
a radar device according to an embodiment includes a transmitting unit that transmits a transmission signal, a receiving unit that receives reflected waves of the transmission signal from a target, as reception signals
Implementation Method 2
a velocity measuring unit that computes the relative velocity between the target and the radar device on the basis of the result of determination on velocity aliasing, and at least one of the reception signal corresponding to the up period and the reception signal corresponding to the down period
Data Source
AI summary
There is provided a radar device. A transmitting unit transmits a transmission signal in which an up period and a down period are repeated. A receiving unit receives reception signals from a target. A distance measuring unit computes the distance between the target and the radar device based on a reception signal corresponding to the up period, as an up-side distance, and computes the distance between the target and the radar device based on a reception signal corresponding to the down period, as a down-side distance. An aliasing determining unit determines whether velocity aliasing has occurred, based on the up-side distance and the down-side distance. A velocity measuring unit computes the relative velocity between the target and the radar device, based on the result of determination on velocity aliasing, and one of the reception signal of the up period and the reception signal of the down period.