Pulsed Radar Channel Impulse Response Artefact Reduction
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Solution Overview
Problem
Ultrawideband (UWB) radar devices face challenges in detecting weak targets due to asymmetric distortions in the transceiver, which affect the generation of channel impulse responses (CIRs) and reduce sensitivity, especially in practical implementations.
Innovation Solution
The method involves transmitting channel sounding sequences with deflections and complementary deflections to the same extent, followed by coherent accumulation and generation of CIRs, which minimizes the impact of artefacts like DC-offsets, allowing for better identification of CIRs and improved detection of weak targets, and can be implemented in a pulsed radar device with a transmitting unit, receiving unit, and CIR generation unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If channel sounding sequences are transmitted using conventional methods with ideal autocorrelation properties, then the radar device can generate channel impulse responses, but asymmetric distortions in the transceiver cause artefacts like DC-offsets that reduce sensitivity and detection accuracy
Solution Approach 1:
The patent applies asymmetry by transmitting complementary channel sounding sequences (one with original polarity, one with inverted polarity) to counteract the asymmetric distortions in the transceiver. This allows the receiver to differentiate between symmetric target reflections and asymmetric hardware distortions, eliminating artefacts like DC-offsets and improving both CIR identification accuracy and detection sensitivity
Solution Approach 2:
The patent implements feedback by using the received channel sounding sequences to generate artefact-free CIRs that are then used to improve target detection. The system continuously refines its detection capability by processing the complementary sequences and using the results to enhance sensitivity for detecting weak targets
2Reliability
If multiple channel sounding sequences are transmitted to improve detection sensitivity, then weak targets can be detected better, but the device complexity and processing requirements increase
Solution Approach 1:
The patent uses copying by transmitting a complementary version of the channel sounding sequence (inverted polarity) alongside the original sequence. This creates a copy that can be processed in parallel to generate artefact-free CIRs, improving detection sensitivity without requiring complex additional hardware, as the complementary sequence is simply an inverted version of the original
Solution Approach 2:
The patent merges the processing of original and complementary channel sounding sequences to generate a combined artefact-free CIR. By combining the results from both sequences, the system achieves improved detection sensitivity while consolidating the processing into a unified approach that reduces overall system complexity
3Productivity
If channel sounding sequences are transmitted without pauses, then productivity is improved, but ambiguity in target distance measurement occurs
Solution Approach 1:
The patent applies periodic action by introducing pause periods between transmissions of complementary channel sounding sequences. These periodic pauses allow the system to maintain unambiguous target distance measurement while efficiently utilizing transmission time, balancing productivity with measurement precision through structured periodic operation
Data Source
AI summary
A radar system can improve performance by estimating a channel impulse response (CIR) in a way that accounts for noise arising from asymmetric interference. The system transmits a first channel-sounding sequence (CSS) that includes a first pulses and a second CSS that includes second pulses. The second pulses are complements of the first pulses. A first CIR corresponding to the first CSS and a second CIR corresponding to the second CSS are combined to produce an overall CIR that reduces or eliminates artefacts caused by asymmetric interference.