FMCW Radar Phase Noise Removal via Hilbert Transform
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Solution Overview
Problem
Phase noise in FMCW radar transceivers degrades the dynamic range of radar systems, particularly in multiple transceiver systems where phase noise from different sources adds up, leading to masking of weaker targets by stronger ones.
Innovation Solution
A method for removing phase noise from baseband signals in FMCW radar transceivers, involving derotating, separating into real and imaginary parts, performing a Hilbert transform, and subtracting the transformed signal from the imaginary part to estimate and correct phase noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple transceivers are used to improve radar system performance, then detection capability is enhanced, but phase noise from different sources adds up and degrades dynamic range
Solution Approach 1:
The patent extracts phase noise from the composite signal by separating it into real and imaginary components. The Hilbert transform is applied to the real part to generate an estimate of the phase noise, which is then subtracted from the imaginary part to obtain a corrected signal. This extraction process isolates the harmful phase noise component for removal.
Solution Approach 2:
The Hilbert transform serves as an intermediary mathematical operation that converts the real part of the derotated baseband signal into a phase noise estimate. This intermediate transformed signal acts as a mediator that enables the separation and removal of phase noise from the imaginary part without directly measuring it.
2Power
If strong echo targets are present, then signal strength is high, but weaker targets in adjacent range or Doppler cells are masked
Solution Approach 1:
The patent converts the harmful effect of strong echoes that mask weaker targets into a benefit by using the Hilbert transform to extract phase noise characteristics. The phase noise estimate derived from the strong signal components is then used to correct the entire signal, including weaker targets, thereby converting the masking problem into a correction opportunity.
3Measurement precision
If phase noise correction processing is applied, then dynamic range is improved, but processing complexity increases
Solution Approach 1:
The patent segments the baseband signal into real and imaginary parts after derotation. This segmentation allows independent processing of each component - the Hilbert transform is applied only to the real part to generate phase noise estimates, which are then used to correct the imaginary part. This segmentation reduces overall processing complexity compared to processing the entire complex signal.
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
The method significantly suppresses phase noise, improving the dynamic range of radar systems by effectively removing phase noise from baseband signals, thereby enhancing the detection of weaker targets in the presence of stronger ones.
Implementation Method 1
performing a Hilbert transform on the real part to provide a transformed signal
Data Source
AI summary
The disclosure relates to removal of phase noise from baseband signals in an FMCW radar transceiver. Example embodiments include a method of removing phase noise from a baseband signal in an FMCW radar transceiver, the method comprising: i) receiving the baseband signal; ii) derotating the baseband signal to provide a derotated baseband signal (x1(t)); iii) separating the derotated baseband signal (x1(t)) into a real part (x1,Re(t)) and an imaginary part (x1,lm(t)); iv) performing a Hilbert transform on the real part (x1,Re(t)) to provide a transformed signal (x″1,Re); v) subtracting the transformed signal (x″1,Re) from the imaginary part (x1,lm(t)) to obtain a phase noise signal estimate ({circumflex over (ϕ)}(t)); and vi) subtracting the phase noise signal estimate ({circumflex over (ϕ)}(t)) from the baseband signal to provide a phase noise corrected signal.