Radar Self-Interference Cancellation via Adaptive Feedback
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Solution Overview
Problem
Conventional radar systems face self-interference issues due to leakage of detecting signals from the transmitter to the receiver, leading to saturation in the analog front end and performance degradation, especially when antenna isolation is insufficient for precise detection.
Innovation Solution
A radar signal processing system with a self-interference cancelling function that includes a signal input end, an analog front end processor, an analog-to-digital converter, an adaptive interference canceller, and a digital-to-analog converter, where the digital interference signal is converted back to an analog signal and fed into the analog front end to cancel out self-interference, preventing saturation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If antenna isolation is used to reduce self-interference, then isolation effect of 20-30 dB is achieved, but the isolation is insufficient for precise detection requirements
Solution Approach 1:
The patent introduces an adaptive interference canceller (AIC) as an intermediary component between the receiver and signal processor. The AIC generates an estimated self-interference signal and subtracts it from the received signal, effectively removing the harmful leakage before it reaches the signal processing stage, thereby enabling precise detection without relying solely on physical antenna isolation
Solution Approach 2:
The system implements a feedback mechanism where the transmitted signal is fed forward through a model of the interference path to generate an estimate of the self-interference leakage. This estimated interference is then subtracted from the received signal in real-time, creating a closed-loop system that actively cancels the harmful effects of inadequate antenna isolation
2Reliability
If the leaking detecting signal intensity is high, then the receiver can detect the leakage, but saturation occurs in the analog front end causing severe performance degradation
Solution Approach 1:
The patent applies preliminary action by estimating and canceling the self-interference signal before it causes saturation in the analog front end. The adaptive interference canceller processes the transmitted signal through an interference model to predict the leakage, and subtracts this prediction from the received signal path, preventing the harmful high-intensity leakage from overwhelming the analog front end components
Solution Approach 2:
The system implements preliminary anti-action by generating an opposite signal that counteracts the self-interference leakage before it reaches the vulnerable analog front end stages. The AIC creates an anti-phase interference estimate and subtracts it from the received signal, neutralizing the harmful effects of strong leaking signals before they can cause saturation or damage
Data Source
AI summary
A radar signal processing system with a self-interference cancelling function includes an analog front end (AFE) processor, an analog to digital converter (ADC), an adaptive interference canceller (AIC), and a digital to analog converter (DAC). The AFE processor receives an original input signal and generates an analog input signal. The ADC converts the analog input signal to a digital input signal. The AIC generates a digital interference signal digital interference signal by performing an adaptive interference cancellation process according to the digital input signal. The DAC converts the digital interference signal to an analog interference signal. Finally, the analog interference signal is fed back to the AFE and cancelled from the original input signal in the AFE processor while performing the front end process, reducing the interference of the static interference from the leaking of a close-by transmitter during the front end process.