Radar Channel Estimation for Non-Linear Distortion
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Solution Overview
Problem
Conventional radar systems suffer from non-linear transmitter distortion, which introduces errors into radar channel estimates, degrading the performance of the radar system.
Innovation Solution
A method is introduced to mitigate non-linear transmitter distortion by using received radar signals to adaptively estimate the distortion, employing a parametric polynomial series expansion to approximate the power amplifier response, and iteratively updating the radar channel estimate to improve the accuracy of the distorted transmit waveform.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If non-linear power amplifier is used to amplify radar transmit signal, then signal power is increased, but non-linear distortion is introduced degrading channel estimation accuracy
Solution Approach 1:
The patent implements an iterative feedback mechanism where the estimated distorted transmit waveform is fed back to update the channel estimation, which in turn refines the distortion estimate. This closed-loop approach allows the system to progressively improve channel estimation accuracy by accounting for non-linear distortion effects without requiring linear amplification.
Solution Approach 2:
The patent introduces an intermediate model of the non-linear power amplifier distortion as a mediator between the transmitted signal and the received signal. By modeling and compensating for the distortion effects through this intermediary representation, the system can accurately estimate the channel response despite the non-linear amplification process.
2Device complexity
If conventional channel estimation methods are used, then processing is simple, but estimation errors occur due to unaccounted non-linear distortion
Solution Approach 1:
The patent employs iterative feedback where channel estimates are continuously refined using the estimated distorted transmit waveform. This feedback mechanism allows the system to achieve high estimation accuracy through progressive improvement rather than requiring complex pre-compensation schemes.
Solution Approach 2:
The patent changes the parameter representation by modeling the non-linear distortion using a polynomial expansion with adjustable coefficients. By optimizing these parameters iteratively based on the received signals, the system adapts to the actual distortion characteristics and achieves accurate channel estimation.
Data Source
AI summary
A radar return channel is estimated at a radar receiver by processing an existing channel estimate along with a radar return signal for an ideal transmission, to produce an updated estimate. Updating can be carried out based on a determination that the existing estimate has become degraded. Embodiments include using a least squares deconvolution to update polynomials describing a transfer function of the channel estimate.