Phase Coded FMCW Radar Angular Resolution
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Solution Overview
Problem
Current millimeter-wave radar systems face limitations in angular resolution and noise floor management, particularly in directional beam steering and interference mitigation, due to the lack of advanced phase modulation techniques.
Innovation Solution
The implementation of phase-coded frequency-modulated continuous wave (FMCW) radar systems utilizing a finite state machine (FSM) to apply phase shifts based on a code, such as the Barker code, to chirps during transmission or reception, enhancing angular resolution and reducing side lobes while allowing autonomous operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional FMCW radar without phase coding is used, then the system is simple to operate, but angular resolution is poor and side lobes are high
Solution Approach 1:
The patent applies phase coding to the transmitted FMCW signal, changing the phase parameter of the radar waveform. By modulating the phase of each chirp according to a code sequence (e.g., Barker code), the system achieves improved angular resolution and reduced side lobes without adding complex hardware structures. The phase coder modifies the signal characteristics while maintaining the basic FMCW radar architecture.
2Reliability
If conventional FMCW radar without phase coding is used, then the device complexity is low, but interference mitigation capability is insufficient
Solution Approach 1:
The patent introduces phase coding to modify the temporal phase characteristics of the transmitted signal. By applying different phase shifts to different chirps in a frame according to a code sequence, the system creates unique phase signatures that enable better discrimination between desired signals and interference, improving reliability without significant hardware changes.
3Measurement precision
If phase coding is applied to improve angular resolution, then measurement precision improves, but processing complexity increases
Solution Approach 1:
The patent implements a coherent integration process that uses the known phase code sequence to correlate with the received signal. The digital signal processor applies complex conjugate multiplication with the phase code, effectively removing the phase modulation and enabling precise angle estimation through Fourier transform. This feedback-based correlation approach maintains measurement precision while managing processing complexity through efficient algorithms.
Data Source
AI summary
In an embodiment, a method of operating a radar includes: generating a set of chirps; transmitting the set of chirps; receiving chirps corresponding to the transmitted set of chirps; using a finite state machine (FSM) to apply a phase shift to each of the transmitted chirps or each of the received chirps based on a code; and demodulating the received chirps based on the code.